NAS-NS-3060
RA OF NEPTWWM’I
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HADIOCHEMISTRY
OF NEIPTUNIIUM
by G. A. krney and R. M. Harbour Savannah River Laborat cIry E. 1. du Pent de Nemours, G Co. Aiken, South Carolina U3801
Prepared for Subcommittee on Radiochwnktry National Academy of Sciences - Nationa I Research Council
IssuancffDate: Dacewnber191~1
Technical lu~lTE~
Information STATES
Published by Center, office of Information ATOMIC
ENERGY
(:OMMl:~l(JN
Sewices
UC.4
This
paper was prepared in connection with work under Contract AT(07-2)-l with the U. S. Atomic Energy Cmaission. By ●cceptance of this paper, the publisher and/or recipient ri[~ht to retain a nonacknowledges the U. S. Government’s exclusive, royalty-free license in and to any copyright covering this paper, along with the right to reproduce and to authorize others to reproduce all or part of the copyrighted paper. No.
~-*~mdM--- ,,———. -.,.-.... .... . . .—...—
.- —---
Foreword The S&committee on Hadmchemiswy is one of a number o’f iubcommitmes working under tl~e Committee on Nuclear ‘Sciencewithin the Natmnal Academ} of Sciences-National Research Counci 1. i!s members representgovernment, industrial and (UniversityIaboratories in Ihe areas of rrucfmr chemistrvand analytical chemistry. The Subcommittee has concerned itwlf with th~ are,~ of nuclear science which revolve the chemist. such as the collectmn and distribu$eon ID” radiochemlcal procedures, the rtitochemicai purity of reqpnts. the piace o! radiochmnistry in college and university PfOiFams.and radiochemistrv in environmental soence. Th!mseries of rnmwxyaphs has qown out of the need for cornpilat!ons of radiochemical information, procedures. and techmques. The S@committew has endwvored to present a serws that will b d maximum use to the working scientist. Each monogrwh presents pertinent information rmqwred for radiochcrnical work with an indivm!ualelement or with a specialized technrque. Exprts in the Particulu radmcfwrnical technique have vvrittm the monographs. The Atomic Eneruv Commission has sponsod the printing of tht sems. TM Sukomrrtittee is confident these publications will te useful not only to radiochemmts but ahio to rtrwarch workers in other fiefds such as phvsic$. b ochemistrv. or nwdlcine who wish tow radiochemicat tswhniques to solve specific problems. Gregory R, Chopp in, Chatrman %bcomm!twe on Radlochemis!rV
“l-
CONTENTS Paqe I.
General Review of the Inorganic and Analytical Chemistry of Neptunium . . . . . . . . . . . . . .
s
11.
General Review of the Radiochem.istry of Neptunium . . . . . . . . . . . . . . . . . . . .
7
Discovery
8
III. Iv. v.
VI.
VI1.
VIII.
Isotopes
and Occurrence and Nuclear
of Neptunium
Properties
. . . . . .
of Neptunium
Chemistry of Neptunium . . . . . . . . . A. Uetallic Neptunitm . . . . . . . , . A.l Preparation . . . . . . . . . . A.2 Physical Properties . . . . . . A.3 Chemical Properties . . . . . . Cmpmds . B. Alloys and Intexwtallic c. Coqmunds of Neptunim . . . . . . . D. Neptmium Ions in Solution . . . . . D.1 Oxidation States . . . . . . D.2 Oxidation-Reduction Reactions , D.3 Dispmportionatim of Neptunitm D.4 Radiolysis of Neptunium Sslutions D.5 Hydrolysis of Neptunim . . . . D.6 Ccqlex Ion Fomation . . . . .
. . . . . . . . . . .
12 12 12 12 14 14 16 20 20 24 24 29 31 33
Preparation of Neptunim Sa@es for Analysis . . A. Neptunium Metal and Alloys . . . . . . . . . . Co~ds . . . . . . . . . . . . . B. Neptunim c. Biological and Environmental S.qles . . . . .
39 39 39 40
Separation Methods . . A. Coprecipitation and B. Solvent Extraction c. Ion Exchange . . . D. Chrowtography . . E. Other Methods . .
. . . . . . Precipitation. . . . . . . . . . . . . . . . . . . . . . . . .
Analytical Methods . . A. Source Preparation B. Spectmphotometry c. Controlled Potential D. Polarogmphy . . . E. Titration . . . .
. . . . . . . and Radiow:ric . . . . . . . Coulomet~/ . . . . . . . . . . . . . .
-2-
. . . . . . . . . . . . . . . .
. . . . . .
. . . . . .
. . . . . . . .
. . . . . . . .
. . . .
. . . .
9
. . . . . . . . . . . . . .
. .
. . . . . . . . ,.. . . . . ,..
. . .
. . . . . .
. . . . . .
. 4) . 41 . 54 . 88 . 104 . 107
. . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . ...123
109 109 114 119 121
PaiJg
IX.
x.
Emission Spectrometry . . . Gravimetric Methods . . . . Spot Tests . . . . . . . . Mass Spectrometry . . . . . . X-Ray Fluorescence Spectrometry Neutron Activation . . . . . Other Methods . . . . . . . .
, . . ,
.
.
. . “.,.. . . . . . . . . . .
.. . . . . . . . . . . . . . . . . . . . .
. . . . . .
124 12s 127 129 129 130 131
.
.
.
132
Collection of Procedures . . . . . ,... . . . A. Introduction . . . . . ., . . . . . . ..”. B. Listiniz of Contents . . . . . . . . . . . ,. Procefiiire 1. Separation of NF1by lTA Extraction . . . . . . . . . . Procedure 2. Separation of P@ by TTA Extracti(nl . . . . . . , . . . Procedure 3. Determination of 23’Np j.n Samples (kritaining LIBPu, and Fission Products . . . . . , . Procedure 4. Determination of Np . . . . . . Procedure 5. Determination of Small Amounts ofNpinPuMetal . . . . . . . Procedure 6. Determination of Np in Samples Containing Fission Products, U, and Other Actinides . . . . . . Procedure 7. Detensination of Np in Samples of U and Fission Products . . . Procedure 8. Extraction Chromatographic Separation of 23%p from Fission ami Activation PTOducts in the Determination of Micro and !’@-microgram Quantitie:3 ofU . . . . ,, . . . Procedure 9. Separation of U, Np, Pu, and Am by Reversed Phase Partition Chromatography . . . . Method for .2;7NP. Procedure 10. An Analytical Using Anicm Exchange . . . . . of U, Np, and Pu Procedure 11. Separation Using Anion Exchange . . . . . Procedure 12. Separation of Zr, Np, and Nb Using Anion Exchange . . . . .
134 134 134
F. G. H. 1. J. K. L.
Radioactive
Safety
Considerations
-3-
.
.
.
. .
.
.
.
.
138 141 14s 1so 1s5 1S8 161
163 16S 167 169 171
. .
.
*
Procedure Procedure Procedure
Procedure Procedure
Procedure Procedure Procedure Procedure Procedure Procedure Procedure Procedure References.
. . . .
13. Separation 0. Np and Pu by Anion F.change . . . . . . . 14. Separation of Np andl Pu by Cation Exchange . .’. . . 15. Separation and RadiQchemicaI Determination of U and Transuranium Elements Using Barium Sulfate . . . . . . . . 16. The Low-Level Radio:hemica~l Determination of 23’Np in Environmental !hmplos . . . . . 17. Radiochemical Procedure for the Separation of T::ace Amounts of 237Np fn)m Reactor Effluent Mater . ,, . . . . . . 18. Determination of ~ in Urine . 19. Determination of 2’1:’Npby Ganma Ray Spectrometry ., . . . . . . 20. Spectrophotometric [leterminationofNp . . . . . . . . . 21. Microvoltnetric Coqlexometric Method for Np with EDTA . . . . 22. Photo~tric Determination of ,h@as the Peroxide Complex . . 23. Separation of Np for Spectrographic Analysis of Impurities . . . . . . . , . . 24. Photometric Determination c)f Np as the Xylenol Orange Complex. . . . . . . . . . . . 25. Analysis for Np by ICmtrolled Potential Coulometry . . . . . . . . . . . . . . . . . . . . . . . .
-4-
.
.
173
.
.
175
.
.
176
.
.
179
. .
. .
184 I 86
.
.
189
.
.
193
.
.
I 97
.
.
199
.
.
201
,. ,“
.
204 206 209
RADIOCHEMWTRY OF ~dEPTUNllUM* by G. A. Bumq’ and R. M. Harbcmlr Savannah River Laboratory E. 1. du Pent de Ncanurs & Co. Aikan, South Carolina 29801
I.
GENERALREVIEWOF THE INORGANIC#J’4DANALYTICALCHEMISTRYOF NEPTUNIIB! 1.
J. J. Katz and G. T. Seaborg, The Chemh?tw of the Actinide Eh???IQnt8, Chap. VI, p 204-236, Johm Wiley and Sons, Inc. , New York (1957).
7 e.
C. F. Hetz and G. R. Waterbu~y, “The Transuranium and F. J. Elving Actinide Elements,” in 1. M. Kolthoff (Ed.), Treati8e on AnaZyticc~l Chemistry of the Eze?TW?Zt8, Volume 9, Uranium and the Ac!iinide8,, p 194-397, John Wiley and Sons, Inc., New Ycl~k (1962).
3.
“Neptunium, “ in P. Pascal (Et.), Noxveau Trvri:e C& Chimie Minerale, Vol. XV, Trcnaurankns, p 237-324, Masson et Cie, Paris (1962].
4.
“!leptunium,” in P. Pascal (Et.), No:xtwzu Traite de Chinrie Minerakz, Vcl. XV, Trcnauraniee8 f’Supplement), p 1-91, Masson et Cle, Paris (1962).
.5.
Il. B. Cunningham and J. C. tlindman, “The Chemistry of Neptunium,” in G. T. Seaborg and J. J. Katz [Ed.), The Actinide Elements, p 456-483, Vol. 14A, Chap. 12, McGrawHill Book Co., New York (19$4:).
%e information=ontained in this the course of work under Contract Atomic Energy Commission.
-5-
axticle was developed during A’1(07-2)-1 with the U. S.
6.
J. C. Hindman, L. B. Magnusson, end T. J. LaChapelle, ‘Chemistry of Neptunium. The Oxidation States of Nuptunium in Aqueous Solution,” in C. T. Seeborg, J. J. Katz, and W. M. Manning (Ed.), The !l”mmeurunin Ekmenta, p 1032-1038, Vol. 14B, McGraw-Hill Eook Co. , New York [1949) .
7.
J. C. Hintian, L. B. Magnusson, and T. J. LaChapelle, ‘themistry of Neptunium. Absorption Spectrm Sttiies of Aqueous Ions of Nept~ium, ” in G, T. Senborg, J. J. Katz, and W. H. Manning (Ed.), The f’mneumniaun EZenm~, p 1039-1049, NcGraw-Hill Book Co., New York (1949).
8.
L. B. Magnussat, J. C. Hindman, and T. J. LaChapelle, “Chemistry of Neptunium. First Prqamtion and Solubi li ties of Some Neptunium C~mds in Aqueous Solutions, ” in G. T. Seaborg, J. J. Katz, and W. ht. Manning (Ed.), The !l’raetiun EZmente, p 1097-1110, McCrau-Hill Book Co. n New York (1949).
9.
of S. Fried end N. R. Davidson, ‘me Basic Dry Chaistry Neptuni~, “ in G. T. Seeborg, J. J. Katz, and W. M. Manning (Ed. ), The ~wn EZ&nants, p 1072-1096, McGraw-Hill Book Co., New York (1949).
10. C. Keller, p 253-332,
The Chauiatq of the TM MIUWZ{WI?EZanenti, Verlag Chem.ie, Germany [1971).
L1.
G. A. Burney, E. K. Dukes, and H. J, Groh, “Analytical ~%amistry of Ncptuni~, ” in D. C. Stewart and H. A. Eliom (Ed. ), l%vgresin in Rucle~ l?ne~, Seriee IX, Anal@?al C’kmhtry, Vol. 6, p 181-211, Pergmon Press, New York (19M) .
12.
J. Korkisch, Mdexm Methode for t?w Separation of Ram?r MetaZ Ione, p 28-196, Pergamn Pre:,s, New York (1969) .
13.
J. Ulstmp, At.
he~~
‘Wthods Rev.
4(4),
of Separating
the Actinide
Elements ,*!
3S (1966).
14.
A. J. Ibses, The Ana2@imZ c~8ii~ of the Actinide l%mmte, Uacltillan Co., Nw York :1963).
1s.
A. D. Gel’man, A. G. Moskvin, L. M, Zaitssv, and M. P. Mefod’eva, “Coqlex Compounds of Transuranides ,“ Israel Pro~am for Scientific Translation j (1967), translated by J. Schmorak.
-6-
16.
“Analytical Chwmistry of the Actinides,” translated by S. Botcharsky, AERE-LIB/TRANS-787. [See alsoJ. AnaZ. Chin. USSR 12, 663 (1957)].
17.
u%lina Nwuibuch &?P Ano~ar.iachen Tranawzne, Part C (1972].
18.
&nelina T~suMe,
P. N. Palei,
Hwuibuch
Parts
Ckmie,
Vol-me 88
der Anoqpri8chen Chemie, Volume 8, A, B, and D (1973).
19.
V. A. Mikhailov and Uy. P. Novikovp “Advances in the Analytical Chemistry of Nepluniurn [A Review] ,“ J. AnuZ. Chem. USSR 25, 1538 (1970).
20.
V. A. Mikhai 10V, Am Z@ica Z Chemiat~ John Wiley 6 Sons, New York (1973).
21.
B. B. Cunningham, “Cheaist~- of the Act~:[ide Elements, ” in AnnuuZ Rev. Nucl. S&. 1+’, 323 (1964).
22.
K. K. Bagnell, The co., lmdon (1972).
II.
GENERAL REVIEWOF THE RAOIOCHEMISTRY OF NEPTUNIU4
Actinide
EZement8,
of Neptunium,
Elsevier
Publishing
1.
of the Actinide Separations El~ts,” in G. T. Seaborg and J. J. Katz (Ed.), The AetJnide EZewenta, Chapter 1S, National Nuclear Energy Series, Div. IV, Vol. 14A, McGraw-Hill Book Co., hew York (1954).
2.
E. K. Hyde, “Rdiochemical Separations Methods for the Actinide Elements,” lnternationaZ Confemwe on the PeacefuZ Uaea of Atomic lhte~, 2nd Ceneuu, 7, 281 (195S].
3.
H. Page “Separation and Purification of Neptunium,” in 2kmeumnienn, p 249-272, Masson et Cie, Paris [1962).
E. K. Hyde, “Radiochemical
-7-
111.
DISCOVERY ANDOCCURRENCE OF NEPTUNIUM
Neptunium was discovered
in 1940 by NcMillan and Abelson. l
They bombarded a thin uranium foil and showed that isotope
of
the 2.3-day
activity
tha:
in the nuclear half-life
reactor it
quantities
production
The first
weighable
quantity
natural
U.
nuclear
reactors,
in 1944.4
to measure the specific of these quantities
When fuels
a:tivity
in nuclear
the following
important.
-8-
in
237Np
Npo2)
wa5
These workers of 237Np.
Np is produced in
reactions,
enriched
isotope
reactions:
of 237Np (U5 ~g of
by Magnusson and LaChapelle
large
but because of its
the long-lived
It was produced by the nuclear
As a result
of 23gNp was 239Pu.2
is used only as a tracer.
in 1942.
were the first
reactions:
as the intermediate
of 239.*,
Wahl and Seabarg3 discovered
relatively
was formed was an
the decay product
23gNp is produced in large
isolated
low-energy neutrons
element 93 produced by the nuclear
It was shown in 1941 that
short
with
r:actors
235U
reactions
~d
23qJ
fueled are
with used in
are increasingly
..- .... .. .. . ...... ... .
Since about 1957, the U. S. Atomic Energy Cwmission =covered
and purified
byprmduct Np in its
‘a’Np is used as target in demand for fueling
The half-life of
the earth.
reactions of
for the production ~adioisotopic
where it
described
it
2s’Np in a s~le
of
quantities
by neutron
It vas found that
Katanga pitchklende of zss~
the abundance
was 2.16 x 10-12 atoms
was 3.10
x
atoms per
]0-’2
230u.7
atcm of
IV.
ISOTOPESANDNUCLEAR PROP[:RTIESOFNEPTUNIUM
The known isotopes Np are listed
in Table
mostly with long-lived
and selected 1.
presented
in Figure
wst
short-lived important
prope-ies chemist
of works
2’gNp and ‘seNp. isotopes
of
Np are
1.
Thermal neutrmn cross Np isotopes
r.uclear
The rad.ioar.alytical
2s7Npand
The decay schemes of these
for
compared to the age
is fotmed continuously
per atom of 23%, while that
S
is found only in trace
previously.G
facilities.
of 23EPu, an isotope
p>wer sources.
of ‘J7Np is very shofi
Therefore?,
in U minerals
production
has
sections
and resonance
are shown in Table 2.
-9-
integrals
Maa@
Half-lifa 22s= 60sac 224
4.0 tin
“%r#,4a)
2s
231
Somm da
252
13
2ss
Ssda
3.s14 1 10”
E a
1.s44 I 10”
af@.01) a
z 10” s.117
E
■
‘S%(d.tia)
6.2S
‘D%(d.h) l’%J[d, Sm) as%(d, h) “%l[d. h)
a(?x
10-’)
1s4
K
2ss
a(clO-’) m
3.1141
10’
Ea
‘e
=
S.ss
‘Shl[d, h)
■
0.0
1s%J[d,5m)
a%[d,ln) I?a S.0SS(48) ■
S.ols(sst]
m(%lo-‘ )
4.92s(lm 4.s64(18] 24s
S.m
22 h
x lo’~
R(O.4S]
‘a-
●-
227
2.14 x 106 yr
Z“u[m, za)
o.56(4a)
0-(0.s2) 2s6=
“’U[d, n)
= O.SII(WI)
l“U(d.4n)
o-
fr 1.s64 s 10’
Ea
%
= 4. 7M(42t)
Sf(s E 10-”)
4.74s(m)
*s’U(O--dmy)
4.764(s8) 4.*1(5.
it)
4.62d(6t) 2s4
2.12 day
5.744
1
10”
B-
‘B~
= 1.2S(4S11
■
J%lm, h) “’urm.7)’ “lh[a-dacay) “’wpm,v)
0.26(s48)
“%(d.h)
1.027(2SW
‘i%(a,p)
0.965(261) 2ss
2.ss dmy
S.la
1 10”
o-q Sf(a
‘n-
= O.?ls(?t) o.4s7(46u
1 10-”)
“’U(B. T) ?’%J(B*Y)
o.263(lm O.n?(zrb) ~
●
O.m(ln) o.220(12b) O.llx(mb]
24e
7.s da
2.s19 m lo”
e-
’13-
= 2.lc[sa)
“’u(B-d-y)
I.so[nt) 24a
6? mlm
2.s95 s 10”
B-
241
16 mla
1.a2
0-
z 10”
-1o-
‘B ‘a-
= O.m(lwl) ■
1..M
~“u(m. pal “’u(m.p)
%p
W?*
~ VW **) m+) Spm
Y
and panty 3.
Vn+l (s/2+) sR7/2Ilr# .
2. :,
<.. h l).
-En9rgY thv 1
5119
Spm and pvlty ml.,
50s3 Lgl’1 LU9.3
!m-1 m. ml-i
3916
ml. }
3301
?12.
265s
Sn.
$6375
Wlb
?5 ?! 5727 ? 85
v.?‘ %2. Y1., w?!..
F~glure 1. Decay Schemesof the Most hn ~rtant Neptuniun Isotopes,237NP, 238Np,and ‘39Np.8$10
-11-
TAOl.E 2 CROSSSECTIONSAND RESONANCEtt4TUWtLSa FOR NEPTUNIIW ISOTOPES’ Nat Nsss
mm
Cspture
Fis!
——-
ion
—
3“
NudMm ..
)
!.(SLQ
“f
.k%z!!l
9cm
2.34
148~
?3s
i?,8(M)
236
.!37
1.85
0.02
600
0
o.ol)13~
;.4$
2,070
600
1.600
23a
2Se
[to
ml
**’NP)
.—
—.— a.
Cross-sections
expressed in
tJ.
J.
R.
,i. t?.
with the fission For 3 MN ntmtrms. For ..reactor matrons’..
l-.
For
H.
Lsndru.
A.
10- Z*C81.
Nasle, N. Lindner.W3tL-slZ63(l!l~2).
J.
neutrons
V.
barns,
spectnu.
CNEMISTRY OF NEPTUNXLU
METALLICNEPTUNIUM
A.1 Preparation Npw?al
was first
by the reduction A sitilar
prepartxi
by Fried and Duvidsoa in 1948
of SO ug of NpFj with M vapor as 1200*C. ti
method was used by Uestmn
snd Eyriq,, L2 Reduction
of NpF+ by excess Ca metal with iodine as a bocmter’)- ‘* was used to produce mltigrsa A.i! Physical
of * metul.
Properties
Pure Np is a silvery 6.3’79C. ?%e =tal the 9eltin8
quantities
point.
ductile
undergoes
three
The physical
Table 3.
-#z”
matal with s melting allotropic properties
point of
modifications me ~rizsd
below in
TABLE 3 PHYSICALPROPERTIESOF NEpTIJNI~~T~&~’J7*L$
A.
Appearance:
Silvery
B.
Melting Point:
c.
Boiling
6376C 417S*c (extrapolated measuremmts
D! .
)ieat of Vaporization:
E.
Properties Aliotmpic
Point:
white
of Various a
Mifi-tio-:
Wtphens a’ detmmined
Ptiit
in
The ~~ific
hst
280 20.48 Orthorhoabic
B
Y
577
637
19<40
18,04
Tw:ragonali
Cubic
tke pressure-taqmmturw (Cp)
ofNp
fis
h!il:h.
relationship Thm Duhng and
walue off W is reached at 140’K and 7,093 cd/(aiol-e8t)
27”C.*1’ tho wv
frtm vapor pf;ssun of liquid Np )
AH 1800”K H 94.3 kcall(g-mm)
Transition teaporature to next higher phase, ●C !Mtmity, glcm’ (at T*C) Crystal Structure
for Np.
[slowly ccatod with oxidel in dry air ●t rcom toaperature)
Tbehigh bi~
specific
Mm can k
●lectronic contributions.
a-!tp occurs *
to i.7”K.a2
entiwtly
acmuntod
No imgvutie
at
for by
orderIn8
A.3
Chewlcal
Properties
HP is a reactive NP”~3+ with
●
‘ ~thin
i$ 1.83 vo~ts.
oxide
and rapid
oxidation
especially
in mist
sulfur
react
resets
layer
to Np@ occurs air.
Hydrogen,
to form the hydride
solutions
to dry air
elevated
readily
t~rature. is given
at @out
at higher
temperatures
haIogens,
phosphorus,
at elevated
solid
Pd. and Rh.
in&-Kl at room tmperature
in Table
and
low temperatures.
compounds of intermediate
The behavior
20”C,
Hydrogen
temperatures,
with U, Pu, Se, Al, B, Cd, Ir,
Np dissolves
solutions
is S~OUIYCOV@*
at relatively
intexnetallic
Fl>r the couple
~ta~li~~
when exposed
with Np metal
F@ ferns
●t
The potential
~tal.
andHzS04
of l{]) toward various
4.
E!.,AL1OYSAND INTERMETALLICCOWOUNDS Co@ete
phase diagrams
Complete miscibility
has been reported Np is a unique
between y-Np and Z-PU. emt-ly
high volubility The intermetallic
~13,
are reported
co~unds
●re
of metallic
obtained
elment
because
of lts
of Np with Al and Be (NpAlz,
Al
or
Be.
Npltc, and NPUIZ) and the intennetallic NpCdlz
betb’een y-l$p and y-U and
in both a-Fu and &.Pu.
NPA1*, and Np8e13) are prepared
with an excess
for Np-Pu and N\p-U.23-2c
directly
directlyby
reducing
The boride:; cmrpounds
(NpBz, NpB~, NpCdG and
from the e’lments.27-2q
-14-
NpFq
Several
.
.
TABLE 4 BEHAVIOR OF NCJMETALIN VARIOU:i SOLUTIONS’1 Solution— H20
Concentration W)
HCla
1.s 6 12
2
Observnt Ions After4 &ys Initiai— -— —. Very slowly atta:ked Irndiate vigorols Coql,ctely dissolved react ion ,, ,, ,, ,, NOvisibla rmction
Someturbidity, hydrated oxide
8 15.7
2.25 9 18
(nlcoot#
2
8 16
HC104
Cone.
Iinim
CQnc.
14s0Jrw lConc.HNOStrace HF
,’
., ,*
Slowreaction ,, NOnoticeable
reaction
No reactionclearsolvent So reactioncl?arsolvent $, ,,
Slight. initial r*actioncessed ,,
someturbidity hydrated oxide ,,
NOvisible
NO rmctionclearsolution ,!,
r.action
Rapid diasoluticn uha hoatai Rapiddissoluti(m whenhosted Rapid dissolutkn uhon hooted Dissolution uhal refluxod
‘z. At ambient taqwratum.
-ls-
!, ,, **
compoundswith noble metals, such as NpPt3 and NpPt5, have been p’repareti by hydrogen presence
of platinurn.’”
10 prq?are several (;.
reduction
of NpOZ at 1300°C in the
Also, Erdinann31 used the same method
other
compounds,
NpIr2, NpPd.3,and NpRh3.
CWPOUNDS OF NEPTUNIUM Cmpounds of Np for the
states
have been prepared.
III,
IV, V, VI, and VII oxidation
The solubilities
anc compositions
of some of t’he compounds have not been verified
because
they
were initiallydeterminedwith smaIl amounts offNp shortly after
discovery
studies
and therefore
have “been made with
oxalates
and peroxides,
larger
amounts of neptunium,
more quantitive
data
Numerous Np compounds, such a$ nitrates, possibly
thiocyanates,
soiverms
such as diethyl
contai.ning
are readily
solvents
l[nvestigation
ether,
saturated
with water.
of co~nds
containing
because
aqueous
in the presence
is produced
mder
of the instability
hydrogen
chemical
reduction
at al.’2
haw prepard
protection
soluble
hexone,
has been limited solution
(on
●
platinum
several
Np(IIl)
All the reagent
-m-
i.e.,
is available. chlorides,
and
in s~lvating
organic
TBP, and other
acid-
trivalent
rqt.unium
of Np(lII]Iin
of atmospheric
and with rongalite,
from oxygen.
Uhere
may be semi-quant:.tative.
oxygw.
catalyst),
Np(III)
by electro-
IW+SO2.(H2O”2H;1O.Wfod$eva COWWCIS from Soiution solutions
and water
with were
purged with pure argon. operations layer
The precipitation
(centrifugation
and washing)
of benzene over the solution.
acetone
or ether
was prepared, The solid
and dried
in a stream
oxidized
is rose-lilac
at room te~rature.
lilac
fluoride
Np(III)
conditions.
h
c~lex
double
were stable
increased
to oxidation
in a few hours. prisms.
with the composition
salicylate
precipitated sulfates
and grayish-
KsNp(S06)5
In the dry form,
during
for
under controlled
of Np(iII],
and NaNp(SO~)z-nHaO,were precipitated. salts
oxalate
the compound is stable Np(III)
were also
Np(III)
of tetragonal
t:olored
NpZ(CGHS~09)S”nHZ0 when well dried;
with a
were washed with
of argon.
was brown and was in the fo:a
a long period
were conducted
rhe solids
but it was appreciably
Np(III) phenylarsonate
and subsequent
prolonged
storage
these even at
teqerature.
Only one solid
coqnmnd
of Np(VIl),
Co(NH~)GN@S”3Ha0, has
been reported.]’ Coqounds and 6. solution,
Table
of Np(IV), S includes
(V), and (VIl are shown in Tables cmpounds
and Table 6 includes
coqounis
●ethods.
-17-
,.
prodtied
in aqueous
produced
by other
5
TABLE 5 ~ A-!; wPTuN1iM cmoums PRECIPITATED Coqoeition Color
of
_
B1uk ,-
gm
ScJ.ubiliw(mNp/1)
3olution
in Di!solw.s
- NaNO, to 9
*%;
5MiiTI@l
uid
3t04
lM N#Xl ~ NaNKiI
m Nmat-
Greea
or
either
base
34 2s
dilute ~ia
O.w (Mt.]@h 2.W m~ 6.3NH20Z O.m W1 O.m HF (mm ●tm) lH HNogM HF lNHF0.02N WlmF 4MHF -lMIF
Purple G?~yi sh 111= Green Green GM Tm
3s
lM Mt,ai -
Brwn
1;
36 32 37 34 m 3D
lM Ml -
%mm
O.lMKIO* Brwn
t.
Gre,n
41
Green Grey
32 40
42
groeo
Tan Greenish blu Greenish
HJO H*O. 0.E4K203,
.0 13
44
blm
Green
lhwll
0.7M14230. O.omw!!, m SmCzll]ol lMIKl- O.m II #0.
3S
36
Bluish lilac 81W Green
43 44
0.3Nml - mm KzS4. - O.a H@b 0.lM
C,ll,AsO,H,
O.sn
Imi
-
0.04M CdlIA@lll; 0.3Mml
45
0
32
tl
32
s
a
I 40
46 34
-18-
TABLE6 OTHERNEPTUNIWCOMPOUNDS Compound Np112 NpH,
Color
W2
Green
Np20~
Dark broun
Np~00 Np09=H20
Darkbrown Redbrown
LatticeSymnetz> Reference 47 Cubic 47 Hexagonal Cubic 48,49 49a Monoclinic Orthorhombic
50,s1
Orthorhombic
47
o=~~eof Np(vII), A ~a ~ap d t@-Lf ~PoLb-Y @(VI), @(V), & Jâ&#x20AC;&#x2122;@(IV) ztith ali.ali metzZa and alkaline earth mataik am know. Abo, tt$tikzr ooqounda me zwported &th the mzw earth, other aotin~.ba, and a?kmzts in Grape 4 to 7.=2 NpN NpF, NpF~ NpFc
Black Cubic 53 LaFs Purple 54 Green 55 Orthorhombic Orange 52,56 A ZaWe tier of fhoro ompozde of alkali or alkalina emth wtile Uith hfp(IV) and fluoride .haoe bum raported~2a fcm .rzioh ~ozmde & th i@(V)ad @(VI) a i%O m zqwrtd. r4@2F Green Tetra~,onal S7 Green M Rhodmhudral N@F I Pink 57 NP02F2 NpCIS 11 Groan NpC1. Orangebrown 11.s8 N#)CIZ Ozmnge 59 NpBrS Green 60 Dark red NpBrb fll Brown 62 w s NpS cubic 63.64 Np# ~ (4 dj fferent 63,64 Strlx tulm) slp~ss Orthorh-ic 63,64 Np2Ss Tetrugonml 63.64 NpS~ Mnoclinic 63,64
0. NEPTUNIUM IONS IN SOLUTION D.1. Oxidation
States
Neptunium exists oxidation
states
the entropy
oxidation
in aqueous
of the
of preparation
reduction
exist
agents.
as hydrated
charged,
hydrated
oxidation
in the absence
only ir, alkaline
neptunyl
itm,
potentials
electrode
and formal
of neptunium ions The formal M solutions
are given
in the stated
potentials
potentials
Because Np02â&#x20AC;&#x2122;
complexes,
8. for Np couples
-20-
in various electrode
The change in the
complex formation
ions.
is stable
in lM HC104 of pairs
in l.OM H2S04 as compared to lM solutions strong
it
The standard
in Table 9 ~ with the hydrogen
medium as the reference.
HCl, and HN03 indicates
solutions;
>nly at high acid
actinides.
are shown in Table
oxidation
of
[Np02(H20)EJ+,
in solnx~ion.
and forms no polynuclear pentavalent
four of these
solutions.
state
compared to the other
wlfate
ions
in acid
and simple methods
The first
only at pH ~7, disproportionates
concentrations,
potentials
7.
Np(VII) is stable
is the most probable hydrolyzes
species,
in Table
to Np(.VI)occurs
The singly
ionic
and (VII)
The heat of formation,
solutions.
individual
are listed
states
coqplexing
in the (III), (IV), (V), (VI),
of HCI04,
c,f Np4+ with
mi&tim
WA
●
lmicFam
.s
WIH,OI
1“
Blua
.4
W(M)
:“
Yalla
.5
WI
.6
(MM;
N@l(HIO]~’
!;,,,~~
~,,,°K CalOr
(kal/ml)
violet
~
Cram
Pink
or red
~;-,tm-”K)l
-117
-, 3.9
-112.5
-.
-231
- *.2L’
NP(>III: . Electrolytic
B
Np(<i I]
a.
ii
J. J.
e.c.
C. Hi diw. J. H. ~]-. R. Rraodt; ”J. M. MIa. * In IKlo..
Ilk?m.
. IK1O, J < A[(II)O
I“
(evaporme] (or
tfi;
,
of die-l lY pwpuvd nissolutlm Ll,N@L In dllure ●lkmlis NP(VI) . maw (or MZj, KjS#h. p9rldnta) in 0,S to 3.SM W
Gr40n*
NP2:-
HCl]
. mm, (hat! w“” Np(Vr] * stoichiutric YIP(V1] . W120H
NP(<vl CO’*: +7
reductlm
*’“ (), Np~Vi . W* ?/Po’) ● I-(5M
-.d
-204
H,/P!
-.
Il.
9s2
(1970).
J-: b. 9.-912 (i970). J.C.Sulltwsm d A.J.Zimlcn. IllLq. hot.
,
-21-
m,.
Latt#m
1.
927
(Iwo).
TABLE8 STANOARD ANDFOR?4ALREOOXPOTENTIALSOF PAIRS OF NEPTUNIUMIONS” Standaxd Potentit.ls -L -1.astl
Fonual Potentials in lM !iclob (Voits)
2Np + 3Hz0 = Np20J + 6H+ + 5e-
-1.42(}
.
Np201 + H20 = 2Np02 + 2H+ + 2e-
-0.96;!
.
Np203 + 5H20 = 2Np(OH)b + 2H+ 2e-
-0.92[1
Sp3” = Np*+ + e-
-0.152
Electrode
Process
Np = Np’+ + 3e-
Np]+ + 2H20= N@12 + 4H+ + e-
0.337
Np’+ + 4H2G = Np(OH~) + 4H+ + e-
0.391
Np3” + 2H@ = Npol
0.4s1
+ 4H+ + 2e-
-1.83
0.1s5
0.447
0.S3D
NP(OH)* = N@~ + 2H20 + e!U@lZ= N@~ + e-
0.S64
Npb+ + 2H20 = NpO~ + 4H+ + e-
0.749
0.739
N@z M NpO~+ + eZNp{OH)~ = Npz05 + 2H20 + 2H+ + 2e-
1.149
1.137
1.219
2NpOZ + }{zO= Np@5 + Z{+ + 2eNp205 + H20 = 2N@)3 + 2H+ 2e-
1.310
Np(lr + H20 = NpOl + 2H+ + c-
1.9s10
Np3” + 2H20 = N@~+ + 4H+ + 3e-
0.677
Npb+ + 2}{20 = NpO~+ + 4H+ + 2e-
0.938
-22-
TABLE9 REOOX POTENTIALSOF NEPTUNIUM(IN VO1.TSAT 25”C) “66-6* :1.
1.(H4 HC1O, -0.477 -1.137 (-l.236)a
,2.
Np
J
-0.677
1 ..—
+1.83
Np3+
--Np”~
-0.938
L
7
-0. 1ss
rl-”—–—
Npo;+—
J
1.(IM Hcl -0.437 -1.13!5 NpO$+——
-0.737
I N@~ -0.936
L-
-0.670
-1.084
-0.99 NpO~
I
1 +0. Ii Np3+ NP*+---
-1.04
1.02k! HN03 -1.138 NpO;‘——
s.
N . p
l.IOMHzS% NpO$+
4.
1.87 1 Np3~-
I
[ 3.
.— -et.137 Npb‘—-—
NpO;
1.W NaOH -0.48 Np02[OH);Z
-0,39 Npo20H
L 0.S82
(-0.’43)
+1.76 Np(04) Q——
+2. 2s Np(oH] ~
J
Np(VII] -—-.---- Np(VI)b ——. a. Standard potential b. According to the half-reaction NpO?- + e- + H20 -Npoidependence of EO on the OH- concentration is expressed Eft = 0.600 + 0.059
●
Np
log [OH”]-”
-2.3-
+ 20H-~g by70:
the
The current-voltage reactions [).2.
curves
of Np in aqueous
Olxjdation-Reduct~on Table
10 lists
c~xidati.on states jlSt-~sferred,
solutions
11.
0.3.
Disproportionation
stable
solutions
equilibrium
state
reaction periods
under~oes
rate. of the in
appreciable
2Np02+ + 4H+ - Np4+ + NpOZ2+
disproportionation
of Np(V) is favored
by
Because Np4+ and NpO;:2* form more
than the Np02+ ion, by the addition
constants,
involve
bond, e.g.,
at ;!:)*C are given
The reaction
Np(V) is promted
that
of Neptunim
concentrations.
complexes
Redox reactions
have a slower
Only the Np(V) oxidation disproportionation.
to change
w~ere only one electron
of the neptunium-oxygen
in lM acid
+ 2HzC)shows that
necessary
(k) and half-conversic,n
Table
high acid
For cases
is rapid.
Np*+/NpQ2â&#x20AC;&#x2122; and Npkâ&#x20AC;&#x2122;/Np022+, Rate constants
2.
NpJ+/Np@+ and NpOZ+/Np022+, the establish-
ment of redox equilibria
redox reactions
and condition\
for Np ions.
fomaing or rupturing
are sliown in Figure
Reactions
reagents
e.g.,
for oxidat~on.reduction
of completing
K, for various
in Table 12 where ~ . JNP(IV)][NP(
[Np(V)]2
-24-
the disproportionation
VI)]
acid
agents.
solutions
of The
are listed
140
h
ml
P4W)-NP(V)
90 ‘V+ 80 -d Iwxn--*[lv) 4 Np( )-NP(IV) Em -
*(V)-
NP(W)
Np(vo NPI,IV)+NP(V) Jt
-%0 ii 3 ~o v w -
I x
30 ~J(-
Hz Oi9Chq8
20 -
Figure
;
4
10 0
1
02 D49chOfgs -
0
2.
-a2
-OA
-04
Current-Voltage
-1.0
-Oa
hd!!L#f -1.2
1A
Curve for Red(tx Reactions
-25-
-!.6 -1.8 -2.0
of Neptunium. 7*
‘1/:
.1*
9+*
l,;:
.1%
●
e
..4
●
,.
‘l~;
20 .,. ~!).!
81)J
~[wfl)
- OpIvll
?0,0,
-26-
to
●
@8
t’
0.* I
●
I *
;:
w’ W“’ ●,e*k.
&,+*+
$j%$
6S+*’96,.,;*
*t * W’”
t.;
●
*“”
.,.
, .,.:.!+.,
,,, .,,,,.
TA6LE 12 EQlJ1L1~[lS4 COUSTAMTS F(R D1SPROPUUIOMTION ~ m(V) IN VNtIOUS M1O SOLUTIWS AT 25°C $*
t2. a*
1*(
solution
—- Ica
Ml Hclo,
4 x 10-7
S.S4M HC1O*
0.127
8.67M HC1O*
200
lM HISO*
2.4 x 10”2
1.$6H H2S0.
0.16
IV)] [NP( VI~ PJPm2
-2a-
The reverse
reaction
in weakly ●cid
takes place rapidly constant 0.4.
in lhl K1O+ is 2.69
causes
reduction
(3.1
tO.2)
reduction other
hexavalent
radiolytic
tively
(0.5
see-]
a rate
constmt
of
to 1.7N HCIO~) and a radiolytic
(G) of 6.4
ions/100
actinides,
Np(Vl)
‘*CO irradiation
The radiolytic
(saturated electron
to Np(V) with
of 2J7Np
ek’.’’-’~’
fh~ared
has a much lower
to rate
of
reduction.
For the ~ m 3.4.
Soluttcms
of Np(VI) by self’-radimtion
X 10-s yield
The rate
(M*ain]l”’*. J*
Rdiolysis o~Neptunlm The radiolysis
.w)lutions.
with
high
yields
●tmospheric
bean?”’s: stability
of O.lhl Np(VI)
in 1.lIM HCI04,
for mdiolysis
oxygen]
exposed
are shown in Tablo to radiolysis.
13.
of ~p solutions to a%
1 MeV
Np(V) has a compara-
Np(IV)
is oxidized
to
Np(V). When 23gNp is prepared uranyl
salts,
by neutron
80 to 90% of Np is in the
-29-
irradiation tetravalent
clf state,*2
Acid ConCent SW ion
ion
—. N@l* + Np02+
Acid Klob
-so-
RadJolytAc Yield G (Iuabm’ of !hll
0.018
4.4s
0.80
S.76
0.126
6.7
0.?
6.7
il. s
4,7’
3.4
1.9
0.05
8.2
o.ab
3.0
0,8
2.1
0.5.
Mydmlysfs of MSptunlm li’b hydrolysis
fON%i On with ~of
proton
●
fron
in tha outer
ion.
Hydr’dysis
8 coordinated
sphorw,
coaplox
ion is m SpOCial caso of
of a matd
Of the
consists
water
molecule
transfer
to a wstor
mlcculu
s.g. ,
with
TheJ most recant
snd extensive
hydrt}lytic
were msde by A. 1. Moskvin. ”
!+ydmlys:,s
listed
(V),
for
in Table
Np ions
14 for
in dilute
increases
with
Z is the
ionic
tendency
to undergo
Pip(IV), acid
increasing charge,
solutions ionic
snd r is
hydrolysis
studies
constants,
and (W] .*
of Np l%, are
The ttmdency
to undergo
hydrolysis
potent ill
[d) where d = Z/r,
the
radius,
ionic
increases
in the
Thus, the order:
]W2+ <N@22+ <Npoaa+ <N#+<N#+, Successive
hydrolysis
in the
formation
sumably
forms
*The stability calculated
of colloidal
irreversibly
constant from KI
in Pu(IV)
aggregates. with
oxygen
%
~
●
‘here
10-1”.
-31”
solutions
Tho polymer cm hyd:roxyl
KI of the Np hydroxo
T water,,
reactions
iY the
result pre-
bridges.sc
complexes icmicproduct
may be of
TABLE 14 FIRST HYDROLYSISCONSTANTS4N0 SCMJBILITYPROOUCTS FOR NEPTUNIUM IONS Ion .— NP’+
!!YQQwS * (~)*
‘8P
Hydrolysis
Produc~
Np02(OH]
9.s x 10-1°
NpO@H
8 X 10-10 NpO;+
N@2(m2
2 x 10-2’
Reference 83
6 X 10-S’ (NpOH)‘+
W2+
——-%
[Np02 (OH)]+
-32-
84
!5 x 10-3 j) x ~()-~
34
8.3 X 10-l S
86
1.3 x 10-9 1o-1o
8S 34
4.3 x IO-*
83
tiskvin’g
repo~s
Np(IV) in queous 0.6.
Tho fo~tion
solution
mt [H+] “:0. 3M.
of w~lex
different
oxidation
jmtential
for
fmm other
states
separating
●s
can be repromnted from
with the
the
●
of polymer
fom
of ligands
of
fmm each other
formation
and hydrolysis
of complex rmctions
sphere
and are
ion formation
between
of Ihe hydrated
in offors
sctinidos
successive
inner
by the sctinides
vuriety
The ~chanism
reactions.
mleculos
formLtion
spocios
Coqlex
cations.
coqmting
water
cation
and
A, e.g., Np(H*O)/+
The ability =gnitude Np ions
for
Ion Fomstlon
~l~x
anions,
evidence
=NpA(HzO)7:+
of an ion to form complexes of the
to fom Np’+
ionic co@exes
(111)
Np(III)
exists
The chloride
+ H20 is dependent
The relative
potential.
on the
tendency
of
is usual]):
>Np’+>Np023+ NpOZ2+>Np02+
Neptunium
in aqueous
and bromide
spectroscopically (see Table
+A-
solutions
coqlexes
in concentrated
1S).
-33-
as Np(HaO)es+.
cf Np(III)
have been studied
LiCl and LiBr solutions
rmt.f 15
Bs&A’ t] -
-m -
ua
2.42
h
-
U*
I.m mob 2.a ncm, 4.* =10. i.a ml%
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6.s4
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n 93
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[NP(C,O.)]J””
l.m mom l.m 2cI0. 0.1 to o. m
-34-
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s,7-olchlomI-hmwI@mllutm m-)
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1O-’M 1oo,
et
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‘so,l;’-
[NpY,’czo.
)1 -
ttw
comtmts twsctlm
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m
# cnt L.m
❑
Ioprltk
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llInMII
L, !hc
c
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1,1,1,.
4,0
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1.3!
[N@,’AC;,l-
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6!
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41
w
117
!10
Neptunium
(I1r.J
Np(IV), strong
which exists
complexes
fores
negatively
trated
most anions.
charged
chloro
H(3 and HN03; these
dangers.
Np(C20s)2
dicating
that
studied
the
is soluble
of the
in solution
peroxide
following creasing
strength Iigand
nature
constants
of Iigands of the
cm anion
ex-
(NH~)zCOS solution
than
the
oxalote
au~d composition
complexes.e
of peroxide
A purple-gray of Hz[hto
Np(IV)
a solution
listed
in TabI@ 15, the according
to in-
formedi by addition
of the
to Np*+:
C104- <Cl- CNOS- <S0~2- ‘U:H@30-
<F- <c20Q2M7ptainiwu
~~), neptunyl of its which
large ● re
<E~A*-
C~As-’
<Qx-
(VJ present
ion,
~-
in
aqMOUs solution
NpOZ(HaO)6+, is u Pom size
and
comparable
low charge. in stability
-37-
in-
which have not been
were a::ranged,
complexes
forms
in concen-
acid.
stability
series
coraplexes
in dilute
coqle~,es,
solution,
to Ll and Pu, Np(IV)
sorbed
is formed by !Iddition
in nitric
From the
are
have not beml made.
precipitate
of Np(lV)
and nitrate
are more stable
studies
coqlexes
Analogous
complexes
carbonate
in detail,
Definitive
first
with
as Np(H@)c@+ in aqueous
os singly completing
charged agent
because
The n~aptunyl complexes, 2+ to Mg2*$ Ca , snd Zn2+
87are
complexes,
much more stable
than
pentavalent
uranium,
P~lJtG~iU.!7!F and alIR3riciuIB COlUpi8X8S.
Studies
of cationic
Cr:~+, Fes”,
complexes
1%”+, and other
of 14p(V; with
cations
IJOt2+,
in HCl(lt solutions
have
been mde.& From the following
serit?s
creasing the
stability
of ligands
strength
first
of the
ligand
?kptunim
the
:bt Table
were arranged
complexes
1S, th{e
;lccording
formed ‘>Ythe
to in-
addition
of
(111)
stability
of ligands
listed
to Np02+:
Np(VI) exists the
constants
in aqueous
constants
solution
listed
in Table
were ~rr =:iged according
complexes
as NpOZ(H:lO]~z+.
formed by the addition
1S, the
following
to increasing of the
From
strength
first
series of
ligand
to
Npf322+:
C1O*” <NO?- <Cl- <9A= <CHJCOO” <F-’ KC204” Neptuniwn(VI
‘J
Very few >tudies Sulfate
compiexes
Np02 ‘+ has a higher
of N&(VII) complexes
have been uade.
of the Np023+ ion in acid tendency
towards -38-
complex
solution formation
show that with
sulfate
ions
than
because
the char~
to heptavaIont
!/1. A,,
the neptunyl of the
is reasonable
:.ncreases
from hexav~lent
PREPARATIONOF NEPTUNIUMSAMP1)ESFORANALYSIIS
NEPTUNIIMMETALANDALLOYS
sulfamic
metal
acid
dissolves
but not
Np slowly.
trated
acid
nitric
Np-Al alloys
Np is dissolved
containing
solution are
method
boiling
by filtration
acids,
slowly
and
Hot dilute
Hl,SO~.
in hot concen-
in 6 to 1(IMHN03 containing are also
sclluble
is to selectively
of NaOH-NaNOs; the
separated
halogen
fluoride.
are soluble
iilg(NO~lz and ‘W.02M KF; they Am alternative
in HC1, otlier
in HN03 or concentr~ted
H2SO~ attacks
in HCl and HClO~.
c[issolve
Np and other
@.05M
actinide
or centrifug~ltion
the Ail in a elements
and are :501uble in
HN03-HF or HC1.
NEPTIJNIIMCOWOUNDS Np02 prepared
soluble tures, the
NpQzn’ group
This
neptunium.
Neptunim
IB.
Np022+ icm.
ignition
in hot
10M HNOs.
refluxing
in strong
addition
NpOZ fired
of the
nitric
of the melt
at very high
in nitric
acid
oxmlate
When ignition
of HF, is required.
and dissolution
soluble
by
acid
teqeratures. solutions
“39-
400 to 600°C is
is done at higher for
Fusion
in dilute
at
a long period, with
acid Blp
containing
is
potassium useful
temperaeven with bisulfate
for dissolving
fluorides are
readily
aluminum or borate
ions.
targets are soluble in hot strong nitric
NpOZ.-Al
tions c
!.
containing
mercuric
and fluoride
acid
solu-
ions.
BIOLOGICALANDENVIRONMENTAL SAWLES Np in these
samples
neptunium
in excreted
sqles.
Most procedures
mental which
samples renders
investigation
soil,
dissolution
saqles
involve
for dissolving, treatment
Np soluble
sa~ies
wet ashing
wet ashingâ&#x20AC;? nitric
acid
strong
agents
peroxide.
sodiun
or dilute
ox potassium acid.
or othler
or a basic
There has been of samples; bcme,
feces,
is l;enerally of \let sucli as
-. 40 -
vegeta-
same methods
of
and
Dissolution accomplished
and dry ashing. perchloric
In some cases
120
numerous
urine,
or iii combination),
carbonate:
step
little
however,,
and the
environ-
fusion
methods.
[individually
with
fallout
many of these
are used
fused
refractory
for Np; Nielsen
oxidizing
and hydrogen
metabolized
be applicable
or a combination
acid
in water
HE:
in tissue.
and vegetation
furic
soluble
fallout
have been reported
Beas ley 11â&#x20AC;&#x2122; have smrized
multiple
types
would probably
of biological
with
in acids.
of plutonium and water
from readily to extrewly
of Np in these
cleterminations tion,
ranges
the
and the stelt
by In
acid
and
or sulsample
i.s
is dissolved
Wr. A.
COW?ECIPITATION
AND PRECIPITATIUY
C!=cipitation tracer
is the “classic”
quantities
aqueous states
is easily
exhibit
separation
{exchange , extraction are
used alaost
separation
is attained
Precipitation
neptunium
ion
and solvemt
extraction
Ix:cause
more co~lete
oxalate
of neptunitm
Precipitation
oxide.
However,
rapidly.
of neptuni~
processing
oxidation
can be aft~ained.
exclusively
mre
,Np in
lbl~havior in coprecipitation,
chromatography,
:separaticm
llecause
to (iiffemmt
different
elements
fc~r s~arating
analyses.
converted
markedly
from other
large-scale
-thod
in radiochemical
solution that
SEPARATICW METHODS
:.s regularly
used
8s u) intermediate
of other
in
to
Np coapowlds
ils
very
limited. The coprecipitation states
of Np is sh~n
behavior in Table
Lantha?u4m Fkwid%.
compound described
lquantitativcly
by lanthanum
The first
separation
‘by
adding
Np is reduced fluoride
oxidation
Pu(III),
and RJ(IV)
fluoride
to the
and lanthanum
of a pure
and LaChrnpelle4’ used
tamination i!;best from H2SO~ because complexes.
different
16.
by Magnusson Np[IV),
,coprecipitation.
of the
of the strong
tetravalent ions.
- 41 -
LRF9
are carried
from mineral
state
[nsoluble
Np
acids. uranyl
almost U
deconsulfate
and precipitated fluorides
TA8LE
16
COPUECIPITATIOM&EMit~litI&TRACE
carrier
Compwnd
AMOUNTS
!!QQM.
igQgQ
NEfY1’lP
Lanthanu
Fluoride
(Y
c
NC
Zircotiw
Phosphate
c c Id’ c c c
Nc
NC
ThOrim Oxalate Lanthaaa9 oxalate ThOrim
Mate
Zirconim
Phenylarsonate
ZimOniw
Benzenesulfinat,e
%dim
Umnyl
Nc
Acetate
Thmhm
Puroxide
Bismth
Plmsphate
Barium Sulfate Potassium
Lanthamm
Potassium
Uranyl
Sulfate
Carbonate
Hydroxides
a. C
indicates co-precipitation ulwier proper condition.
c c c c Nc c
Poor
Nc
K
K
Poor
c
M
Nc
Nc
Nc
K
NC
c c
c c
near.llj’ complete
b. NC indicates co-precipitation less percant under proper conditions.
-42-
w
than
a few
includin~
the
carriers
me
rare
earths
and Th also
added to decrease
line earths.
The fluoride
acid-soluble
sulfates
oIrto hydroxides
precipitate
with bromate
but other
and lanthanides
removal again
Np is reduced
coprecipitated
dioxide
preceding
precipitation
with the
alkallj.
yields
hydroxide.
K.uoride-solubl(e
Np(VI), and,
hence,
LaFs pre[:ipitation
stelp.
After
to the
state
Ix)travalent
Pa is co~trecipitated
LaFS.
to
Oxidation
are m}t oxidized
in a subsequent
of solids,
either
untjl~. fumes of HzSOU appear,
with
at room temperature
of Zr md alka-
is converted
by evaporating
acti.nides
Hold-back
the precipitation
by metathesis
are precipitated
prec:ipitatc.
LaFs precipitation
and
WILthmanganese
zis required.12i
has been used to separate
LaFt
NI~(IV) and Np[Vl from
Np(VI). 122 Zimoni.wn and other
elements
A variation it; based
Phosphate.
of this
the hexavalent
I%~(IIIj;
X!No 3 -
is heated
phosphate. and !3eaborg121
zirconium
::0 oxidize
ion and
Np and Pu to
H3P04 is added to ~:arry tetravalent is
treated
and then with
Np is carried
U(VIâ&#x20AC;&#x2122;j are not
â&#x20AC;&#x153;fiompson, f~fter
cycles.
the solution
solution
bismuthate
witl~ zirconium
method by Magnusson,
state.
The supernatant
io]~s of Np, Put Ce, Th,
coprecipitated
on oxidation-reduction
NaBi03 are added,
destroy
are
Tetravalent
carried.
with
with ferrous
zirconium
The zirconium
HF, and Np is separated
Isxcess hydrazine :Lonto yield
pho:~phate, pho$phate
but
to
Nlp(IV) and Pu(III)
and
is dissolved
from Zr by coprec:ipitation
-43-
ions.
in with
LaF$.
Barium
Sulfatu.
carrier-fne barium
trace
sulfate
potassim
to 1 mg are coprecipitated sulfuric
and hydrogen
frcm most other
acid
levels
from strong
salts
the bariw
Ce, Ba, La, and ?dp(iti) in quantities
ele~nts,
sulfate
containing
acid
peroxide.
This
Np was separated
and reprecipitation chromic
acid;
After
peroxi&
and again
the precipitate
co{mting
of the
ami also
applied
Hyiraeich
of Np except
and tetravalent
states
solution.
Strong
organic thiat
coaplexing
foxm amine
was reduced with
with
the Ce,
to Np(IV) with
bariu
sulfate.
The method has been further of envi::onaental
hydroxides
are carried
for precipitation bases
are’ amphoteric
carried
sulfuric
23’Np \/as determined
Np(VII).4SS127-129
of reagent
that
of
by gamma modified~z”
and biological
1s, p176).
Insoluble
.
a separation
by dissolutiawt
coprecipitated
to a wide variety
{Procedure
sal@es125
states
]z’
containing
causes
N (IV) was net ,p
was filtered,
filter.
>99.7% by
from concentrated
Bat and La. The Np in the supematant hyclrogen
solution:~
from
Generally,
ligands. complexes
depends
on the
When the
solution
solution
insoluble
oxidation trivalent
The choice of the
contains
solution contains in strong
is used as preci.~itant.
-44.
the
composition
Pb, Zn) cm when the
or are
all
most effectively,
are used when the
(Al,
Cc), Ni, Ca, Mg), mnia
copreclpilate
cations
contains cations base
(Cu,
Other In.qmnio with bismuth
phosphate
gives
sulfate
results
sulfate
lanthanum
to those
coprecipitated
of lanthanum pot~:ji~
described
and
double
for
sele -
the double
but does not have any advantages.lso
cop~cipitated
cations
and Aten132
actinides
with
is completely
were pmr
with
less oxalates
and uranium
from other
of tetrava-
peroxide.
peroxide,
but
results
to the
cations
iodates.
phenylafionate
and
foâ&#x20AC;?? coprecipitation The twtnsuranium
to those
of
elements
and from each other
similar
and
by a series
outlined
for
133
concentrating
elemmts
thorim
and eerie
and Akimova13* have proposed
Kuznetsov
form he~nitrato
include
Zirconium
are specific
steps
phosphate.
for
thorium,
from solution.
of oxidation-reduction
uranium
coprecipitation
for Np(IV)
t@%?&p~t~t8.
benzenesulfinate
are separated
reagents
are
â&#x20AC;&#x2122;31
l%is was attributed
peroxide.
and zirconium,
tetravalent ions
zirconium
the
by thorium
coauon carriers
Othfm ~cznic zirconium
tricarbonate.
peroxide
carried
elements
of Np[V).
Other Lanthanm
uranium
transuranium
uranyl
described
thorim
Neptunium
presence
of the
with potassium
Dupetit
the
with
similar
The pentavalent
lent
Np(IV) is
and the double
Coprecipitation
potassium. nate
Copmtipitants.
the
from very species
tetravalent
dilute
in nitric
-45-
a number of organic cations
solution!;. acid-nitrate
of the
txzms-
Np(IV) and Pu(IV] salt
solutions,
and these
cations
are coprecipitated
of heavy organic was the -st
effective
solutions,
U(IV),
dimethyl
Excellent
organic
elements
with
nitrates
and the shove,
selective.
coprecipitate!
nitrate
with
Np[IV)
quaternary
ammonitan
and benz?lquinc~lium
colqounds.
iron, chmmim,
containing
soluble fomed
cyclic
cyclic
by the
organic
3ulfonic salts
catiom
reagent.
the precipitation
is
carried
with
manganese,
groups,
that
are {coprecipi-
of a ba:.:c Compami
dye
to the organic
is more (c(mpletel but
less
sodium uranyla~~tate.
Precipitation
used as an analytical
cat:lons
that
be $teparated
fom
of macro quantities
or radiochernicul
insoluble
solution
a method such as alpha less
10U solubilities stoichiometry usefulness
health
in aqueous or necessity of direct
solution; for
cotatting
-46-
these
must
free
from
is usually
mo:re rapid
of Np compounds have
howevlm,
calcination
gravimetric
If other
is :r(:latively
A nusber
hazard.
of Np is
method.
compounds are ljresent,
When the
first.
ions,
and offers
the
In mncentrated
earths,
reagents fom
Prvaipitatwn.
other
butylrhodamine
â&#x20AC;&#x2DC;Sâ&#x20AC;&#x2122;
Np(Vt)
seldom
mnium,
precipitates
(arsenazo]
~tudied,
was with
from rare
With many organic
tstad
precipitates
attained.iâ&#x20AC;&#x2122;s
was
tetravalent
cation.
and Ce(IV)
dibenzyl
the nitrate
rwagents
coprecipitation
separation
and copper
Of the
fi(IV),
Other
and Pu[lV). bases,
cations.
with
indefinite
i:o the oxide
deternunation.
limits
No information
@ihti&8.
probably
because
it
is
rapidly
Np(IV] is precipitated potassium,
oxide.
filter;
it
from mineral
The brown-green
is easily
volubility
studies
lM NaOH is
<1 mg/1.
are
solution
is 0.18 g/1.35
g/l;
There
as dark brown acid
solution;
was speculation
with
exces:;
is given
of the uranates
tion
neptunates
Grayish-lilac
in dilute
hydrochloric
compound was quite
leave
given
to a solution
Iiterature38
Np(VI)
stable
nature
is precipitated
ammonia from mineral
Studies
some question
When reported
on the variable
as to the composi-
above. 137 colored
Np(III)
HCl solution
while
sparging
to oxidation.3~ -47-
fluoride
of Np(III)
of ammonium fluo::ide acid
the exact
a brown compound with
composition
a dilute
ammonium
and in 2.2M NaOH,
a:; 25 mg Np/1. ‘5
Na2Np207”xH20 is precipitate(i.
Rongalite
in lM NaNOJ -
in dilute
in tile early
is the precipitant,
by adding
to
No formal
as NpOz(OH]9HZO; however,
volubility
cipitated
is difficult
The volubility
co~sition
Fzuotid88.
or
as NHqNp03-:ti20 or an analogous
(NH4)2NP207”H20
the
hydroxide
volubility
~!/l;
atmosphere.
by sodium,
acids.
has not been confirmed.
sodium hydroxide
of the
solutions
as tho hydrated
in lM NaOH, 0.017
sodium compound as well of the precipitate
acid
but the
is green.
“hydroxide, ”
even in an inert
in mineral
reported,
Np{V) might precipitate
on Np(III)
gelatinous solid
redissolved
Np (V) “hydroxide”
that
oxidized
and ammonium hydroxides
hydrous
0.014
is available
is precontaining
or hydrofluoric with
argon.
Np(IV) fluoride
acid
The dry hydrate
is precipitated
when hydrofluoric
acid
is
added to an acid
solution
of Np(Iv), Ammonium Np(IV) pentafluoride precipitates as a bright-green granular solid when hydrofluoric acid is added I:oa solution of Np(IV) containing NH~+ ions. A similar precipitation in the presence of potassium ions yields a bright-green precipitate that X-ray diffraction indicates is KNpzF9. ‘Tiesupcrnatant lM HF O.OIM NH,,’> from precipitation of the ammo:liumsalt contained 1.1 mg Np/1 two hours after precipitation; t!h:solut~ili.ty of the potassium
salt
was 1.7 mg Np/1 after
16 hours
in O.SM HISOb -
0.5M K2SOJ4- ;!MHF.3* A double fluoride precipitate of La :md Np with an approximate composition LaIZNpFIOOXHZOis obtained by ilddinghyd.rofluoricacid to an ac~d solution o
equivalent amounts of La
3+
and Np&+. The
volubility of the salt in water was 4 mg/...39 Rubidium neptunyl(V) fluoride was prf:paredby injecting a chilled W.IM
HN03 solution of Np02+ into a chilled solution of
%12M Rbl:at O°C. The gray-green precipittltewas washed with small amounts of water,
methanol,
and acetone
followed
by air
drying.
13*
0XUikt88. Brown NpZ(CZOq)3*nH20 (n ~111)is precipitated by adding oxalic acid containing Rongalite i.rtoa dilute acid solution of Np(IIl) also containing Rangalite.,The compound is appreciably oxidized within a few hours.32
-48-
After
valence
bright-green
containing
HN03 by the
a function (Figure
addition
of the
concentration
At oxalic
bility
varies
between
tion
is varied
acid
all
The soluble
near
in the
Ethyl
ammonium oxdate. liquid
that
yielded
alcohol
varies
acid
tetravalent
as
acid
concentra-
state, is
attained.
XH20 has be~., isolated. to O’C to remove cxccss
addition
dark-green
in 1 to
is very tlependcnt
from a number of cations
complex was cooled
(VI)
O.lM, the volu-
The solukility
(~U)Q[~(C20~)~]-(~~)2C20~= aqueous
or
i~cid arid oxalic
concentrations
the neptunium
acid, ko
T.le volubility
of nitric
1 and 4M.
separation
The salt
acid.
[V),
6 and 10 mg/1 as the nitric
between
on maintaining Significant
of oxalic
ascorbic
from solutions
5 to 50 g of Np(lV),
3).
green
to Np(IV) with
Np[C20~)2D6H20 is precipitated
originally 4M
adjustment
produced
crysta..s
an oily,
when treated
darkwith
96% ethanol. Green neptunyl(v] when a solution of oxalic
acid
containing
(Np02C20~H”2}120) is precipitated
of Np(V] in lM HC1 is treat~d in tert-butanol.
Neptunyl(VI) crystalline
oxalate
solid , is precipitated 20 to 40 g Np/1 by adding
oxalic
The volubility
increased
to ‘v1.5 g Np/1 over
In lM INOJ at
zcid until
the
solution
in 0.5MHN03 - CI.023MHZCZ04
14”C, the volubility
-49-
a grayish-~reen
from 2M HV03 - O.OSN KBr03
is ‘IJO.3MH2C20Q.42
20”C.
a 10% solution
bl
oxalate (Np02C20~”3H20),
from W.5
with
the
temperature
varied
range
from %3.8
to
O to
~3g
- ——
100r
:1’:”’”:230’’’’ 0.7[3
/“
to-–
~1
•~
1.64 _
-2.813 : B- 3.7fi 1
3 0.’01
Figure
o. I Omlic Acid, M
3.
Volubility
-so-
of
Np(lV)
~~
oxalate
I.0
%0.75 g Np/1 as the oxalic
acid
concentration
varied
from WI.002M ,
to w. lSBL Np(IV) peroxide
Pervti&.
reduced
peroxide.
soluble
The higher
valence
complexes
fio
crystalline
that
through
precipitates.
the highly
colored,
of plutonium depending
on the
The volubility
solution.
of
are rapidly
are characteristic
o: nitric
of the concentrations
addition
peroxide
forms were prepared
of the precipitation
as a function
states
neptunium
does not progress
peroxy
peroxide. acidity
~â&#x20AC;?o
to Np(lV), and gray-purple
The precipitation
from solutions
(V), or (VI) in >3M HNOJ by the
containing Np(IV), hydrogen
is precipit:lted
acid
is
reported
and hydrogen -%
peroxide.
A minimum volubility
solutions not
of ~lO-uM neptunium
reproducible
Iodate8. reported.
at nitric
Precipitation
a tan-brown
Np(IV) iodate,
in lM HC1 - O.lMHIOS
volubility g/1.35
These solubilities
some Np was in higher Amtate.
Rose-colored
sulfuric
acid
solution
ence of potassium M.1
b-te
iodate
were
of <2.5M.
is precipitated acid
solution.
when The
is 0.8 g/l; in lM HC1 - O.lM K103, to be high,
possibly
because
states.
N~@Z(C2H@z)s nitrate
that
in
has not been
solid,
mintral
appear
oxidation
a sodim acetate - sodim
ac;.d concentrations
of Np(IIl)
HIOJ or KIOg is added to a dilute
0.08
The solubilities
1.5 to 2.5M HNOJ and 4.5M H::02.
readily
occurred
solution
has been heated
to give
NpOZ2+.
is precipitated
is added to a dilute to 90°C in the presThe
volubility
g/1 in 0.5M H2SO* - 0.07M NaNOs - 2MNaCzH~02.38 -sl-
when
is
No sinple
Ccmbo?latea. rqor~al
carbonates
A light-colored
precipitated
of NF(III)
precipitate
by addition
of solid
of NF(V), KYpOaCOs, is
alkali
carbonate
of Np(V) ❑ade by reduction
to a solution
and Np(l V) are
(to about
of Np(VI) with
pH 7)
iodide
ion,~3 Phosphate.
A green
gelatinous
is formed when phosphoric or nitric
❑g/1,
acid.
and the volubility
Np(lII)
as the
Np(III)
is produced
complex
at %SO°C using sulfates
are stable
Np[IV)
is crystallized
is %16 g Np/1.
Pu(IV) sulfate
co~ounds salts, Other
hydrochloric
alkali
In the dry form,
solutions
are given that
ions,
Several
of
with the
argon
complex
teqenture.32
sulfuric
Np(SOk)2*:cH20.
acid
as a
The volubility
of Np(V) and Np(VI) have on volubility.3S
Np(IV) colpounds
be precipitated metal
and sparged
concentrated
presumably acid
precipitation
even at increased
from hot
is expected could
report
KsNp(SO+)b und NaNp(SO~)2*nH20.
to oxidation
but no data
Conpounda.
been prepared.
and Gel’man32
mductant.
Sulfuric
it
in lM HC1 - O.SMHsPO~ is W56
in dilute
compound,
reported,
in hydrochloric
sulfates
Rongalite
been reported,
is added to Np(IV)
in lM HNOJ - lM H#O~ is %134 mg/1.+5
Mefod’eva
bright-gnen
Np(HPOb)a”xHaO,
The volubility
sulfates.
not
acid
precipitate,
Although analogous
fmm a solution
to
containing
and Np(IVj.
Np(IV) chlor’Lde
Yellow CszNpCls was precipitated
coaplex
salts
by ❑ixing
have solutions
of Np(IV) and CSC1 in 2 to llM HC1 and saturating the rwsulting
-52-
solution
with hydrogen
<0.DIM ~d
increases
chloride.
19N3volubility
to w1.4M in %lM lIC1. ‘“~
[( C2HS)~N]zNpC16, was precipitated chloride
in 12M HC1 to Np(IV)
complex salts
by adding
in 8 tc) 12M HC1.1”2
[(C2~5]4N]2Np02C14was precipitated
(bright
yellow),
The phenylarsonate reported.32
by the
They are quite
stable
dry.
-s3”
yellow),
other
Yellow
same procedure
used (Ph4As)2NpOC15
and CszNpOzClk (dark
of the same pr>cedure. and salicylate
compound,
Several
reportecl.
and Cs2NpOC15 (bright
CsSNpOC14 (turquoise),
were made by variations
A similar
tetraethylammoniwn
of Np(V) and Np(VI) have been
for the Np(IV) salt,1”3
in ~lOM HC1 is
‘q
of Np(III) at :unbient
yellow)
have been
temperature
when
B.
SOLVENT EXTRACTION Solvent
organic of its
extraction
solvents rapidity,
with
used most often
simplicity,
and reliability).
and specificity
systems,such
as fluoride,
chelate
are examples
extraction
In chelate
sulfate,
extraction of bath
and 8-hydroxyquinoline
replace
ions
almost
soluble tion
in such organic
systems,
extractable between
several
oppositely
to Np(IV), to give conmonly isoamyl
used for alcohol,
such as hexone with
complex
an uncharged
actinide
Generally
the effi-
systems;
other
and phosphate,form complex ions
extraction
extrac”:ion
systems
such as lTAp cupferron, coordinated covalent,
ions.
water cheiate
are possible
cation
extractable
pentaether,
and dibutyl
and diethylether, the order
-s4-
of
that
are
In ion associa-
attraction association
with
system, is coordinated
nitrate
Ion association TBP, hexoneo carbinol.
which fom
Np.1bbD1”5
from neptunium compounds
is associated
include
for
acetylacetone,
such as ether
species.
and
by which uncharged,
In one ion
compound
Np extraction
nitrates,
extraction
formed by electrostatic
organic
and the
because
Solvent
ion association
❑echanisms
charged
an oxygen-containing
wparation
compounds as hydroc~rbons.
compounds are
immiscible
is inhibited.
compounds
and form neutral,
into
from ch’loride
among the solvent
systems,
for
systems.
are decreased
neptunium,and There
solution
is probably
❑ade from nitrate
of Np is usually ciency
of Np from aqueous
solvents
diethylether, For solvents
coordination
extractability
ions
complexes
of the various
oxidation last
states
is usually
two states
generally
(IV) oxidation
state
extracted
hexone
into
agents, the
which fom
stable
extracted
considered
is poorly and dibutyl
state
most efficiently.
and other
complexes
usually
An exception
(Table
may be the result
The but
is
strongest
the ❑etal
nitrates,
complex
is usually
of the
and (V).
actinides
Thus,
the
instability
TBP, TTA,
(IV) state
17) is lJp(IV]-TBP;
to
most
however,
of the
these
oxidation
in the aquebus solution.
production-scale
and Schulz
neptunium
that
form strong
solvents-such
phase.
Of these
as benzene
compounds,
thenoyltrifluoroacetone
separation
schek
oxidation
solvent
the
tiith
metal
or CCl~rthan fluorinated
include before states.
and analytical
TI’A extraction the analysis i27~]92#*”9D1’0
-55-
extraction. reagents
ions
are mme soluble
have
in nonpolar
in the aqueous B-diketone,
(TI’A) has been most widely
of ?+@in radiochemical
Many variations
complexes
These complexes
organic
including
have reviewed
number of ~i-functional
coordination
been investigated.
and Benedictg
processes,
C71ezute s~atema. A large
of its
with
extract
of the
the
For TBP and chelating
The tendencies
agents
Groh and Schlealh6
tion
the
(IV) > (VI) > (111)
conrplexing
effectively. exceptions
is
(V)~ with
by diethylether
carbinol..
giving
nd
to bm nonextractable.
extracted
coordination
oxidation
form complexes
state
(VI) > (IV) >> (111)
used
appl:lcations.
as a part
of the
2for
extrac-
1’7~*’a total
of Np or the determination
.
TAUE 17 VAAIATIOUW ESTRACTIOII COEFPICIU(TSMITMOXIlhTIOR STATE
QElmkk ll##t— 1*
TW-korosem
O.sm nA-xylOm Di*thyl
●Clwr
Aewau m
Pmula
!QQw_&MM_
Imi)*
1J4 HloB edk tNoB
YFXQ__!Mw_ 3.0
,.-6
10’
0.1
0.13 ~o-.
0.3
.!Mw_&Qv_wQ 11.0 10” ‘
0.014 ,.-8
-(III) :!l. s ~@
4.6
z.~, 0.(104
m
O.m 10-0
..31 1.:!
lM MEb-sat m,mo, Ibx$nw
Ossm tmm-11.lm
0.14
l.”
9.e
m8N08 C*
H40,
0.3
-56-
1.’
,a.5
~lw
Some data 0.5M
TTA
given
in xylene
in Table Shepard
tion
for
the extraction for
a range
of nitric
cations
into
a,cid concentrations
are 1
18.
and Meinke have compilti
cunres
showing extraction The data
of elements.lso extraction
of Np and other
is useful
a useful
as a function
show that
to separate
set
of pi-l for
by judicious
neptunium
of TTA extraca number
pH control,
?TA
from many other
elements. Basically, of Np to the fering
the lTA method depends highly
ions
are
(Procedures
extractable
stabilized
tetravalent
and co~letely
hydro~lamine
state
in inextractable
1 and 2, p 138 and 141],
IKl is rapidly
on quantitative
with
hydrochloride-potassium
hydrochloride-ferrous
chloride.
and Pu(III]
remain in the aqueous
fering
cations
directly alpha
and U(W)
for
are present,
emitters
Fe(III),
Zr(IVl,
but separation ‘lTA-xylene do not if
1s verified
into
interfere.
present
extraction
is attained 8M Ii?#3s. Sulfate,
prevent
interference. -57-
. . ..
.
phase,
height
the ‘ITA,
If no inter-
aro camplexed
other
lM HN03,
f-
the Np(IV)
oxmlate,
from
analysis.
extracted
actinides
phosphsI:e, phase,
or hydroxylamine
can be evaporated
pulse
by stripping Trivalent
sulfamate,
of separation
and Pa(V) are strongly
in the aqueous to
by alpha
states.
is eXtrdCted into
the extract
The efficiency
Cotmting.
inter-
in lM HNOs or lM
femous
iodide, NplIV)
while
oxidation
Neptunium
reduced
reduction
from
the
and lanthanides and chloride, with
Al’+ before
TABLE 18 EXTRACTION
COEFFICIENTS
.—. Ion NP(III) @(IV)
FOR VARIOUS
!!!Qd?Q 1.0 1,0
IONS IN1-O 0,5M
Extraction at —. <3 )(
Coeft:lcient 25*C —— Jo-s
1 x 10’
8.0 Np(V)
0.8
<5 x 10-’”
f@@I) Pu(III)
0.8
<1 x ]()-’
1.0 1.0
1 x 1.0-6
8.0
Pu(IV)
1 x 10’
F%(V)
1.0
<l x 1.0-2 <1 x 10-’”
Pu(VI)
1.0
4 x 10-3
U(VI)
1.0
3 x
Fe(II)
1.0
<l x 10-3
Fe(III)
1.0
375!
Co(III)
1.0
1 x 10-5
Ce(IV)
1.0
1 x Los
H(W)
1.0
1 x 107
8.0
25D
Aa(III)
1.0
1 x 10-9
Al(III)
1.0
1 x 10-20
Na
1,0
1 x 10-20
m (V)
1.0
4 x
Th (IV)
1.0
3.1
-S8-
TTA-XY1.ENE1’9
10-5
10-~
The relative The nominal 10 M. 151
standard
deviation
decontamination
attained
#152
Some data
perchlorate
systems
for a:he analysis
is 22%.
from plutonium
on the extraction
is
10g to
Np from sulfate
of
with TTA have been giren
by Sullivan
and and
Hindman.93 ITA extraction also
preceded
been described.153-L56
special
materials
where a combination
was used.
separating
17 gamua-emitting
The individual
radionuclides,
by ‘ITAsolvent
nuclides
m method including
extraction
were determined
has
from numerous
method:J including
of
Holcomb157 has described
mderator
cycle
Np has been separated
extraction
heavy water
by a LaFs coprecipitation
lTA
for
23gNp, from
and anion
ty gamma counting
exchange. and
gamma spectrometry. 8-Hydroxyquinoline Np(CSHGNO)~with tion
of
hydrolysis extracted
extract
is back extracted Separation Pu and probably
as a function
ofpH
in CHCIZ is shown in Figure only
of the metal almst
chelates
Np(IV) and H[N@*(C9HGN(~)~] with
a number of elements
8-hydroxyquinoline actinides
forms the following
at pH 4-6, cation
and at this
occurs.’
quantitatively
into
with Np: Np(V].
into 4.
O.lM
The trivalent
@i appreciable
~’] Np(IV) cupferron chlomfom
Extrac-
is
from lM HCl and
in 8H HC1. i50a with
acetylacetonate
has application
has been reported
for Np.
-s9-
for U and
~-
I
-1 PO(v)
p(w)
cffdUI
‘7
1
Acum
PO(v)
RO(m
Am(m)
L
;
;/\
et(m)
4
6
8
-
10
+-
pl’t FIGURE
4.
Ftercentage
CM(III),
/’CHC13 [Na, NH*,
Ada.
Extraction
Tracer Quantities of Ac(I!II), Am(III’), and Pa(V) with 0.lM8-Hydroxyquinoline 1.OM 8-Hydroxyquinoline/CHCls [p = O.lM 25”C]. [C. Keller and PI. Mosdzelenski, Radiodfim. Supplemented]. of
Cf(III), N (IV), and of Ra(II ! with H)CIO~,
?, 185(1967)
-60-
Extraction of plutonium dibenzoylmethaneor salicylate has been reported.
1‘g~ 1‘o
sc}lutiont
Neptunium
dibenzoylmethane
so Pu and U, which form extractable
separated.l
solution and fission
products
(except
Np(IV] is strongly 6M HCl with
isopentanol
for
large-scale
from 1 tcl 4M HNDa and 1 to
nitrate
under
salts
that
affect
free
TBP concentration,
but
have been summarized
the
ex-
and
Increasing
nitrate,
the nti,trate
of Al or Ca favors
generally of concentration
ext::action.
complexirlg
temperature,
used
TB~ forms an organic-
the metal
include
is a useful
ions,
Other reagent
and mi],ing time.
work with TBP has been given by Geary,lsG
and chemical
is
in n-butanol
is not, widely
separation.
complex with
the extraction
Np
The TBP-HNOS system
processing
M(N03)149ZTBP.lb>
(V),
from U and Pu.’6b
@8t4w18.
analyti~al
coordination
of the early
a chloroform
IJOZ2+, Am(IIX],,
l-nitroso-2-napthol
and is separated
for quantitative
physical
from 3M HNCSwith
Np(V) and (VI) are not extracted.1s3
Ion A880CiatiOrI
the type
can be
Zr and I%) do not extract.~62
extracted
at pH 9’ to 10 with
soluble
complexes,
4-benzoyl-3-methyl-l-phenyl-ppazolin-5-one;
same conditions,
adding
PuIIV)
of N-benzoylphenylhydroxylamine;
sYStm
in aqueous
59’!S1
Chmutova et CZZ.extracted
tracted
is unstable
properties
of TBP as an extracting
factors puritY,
A S_rY The a,gent
by McKay and Healy. *G7 Other discussions
the use of TBP are in References -61-
168-170”
‘xtract~’on
by
Coefficimts
‘f
for many elements concentrations data
for
a variety
have been reported
are shown in Table Np(VI) is almost
Cr[III),
Fe[II),
in one stage involves
various
sequence
> Np(IV) > U(IV) > Th(IV], extractability
HCl solutions from nitric ficients because
acid
similar
but
are observed
quite
actinides stable
deleterious
effect
with
on actinide
these
is
are extracted
from
coefficients
Lower d:.stribution
from perchloric ion.
acid Strong
as coefsolutions couplexing
the extractability
cations anions
atomic
5 ar,d 6).
distribution
extraction.
-62-
sequence
incratsing
actinides
P@k3-, and F-, reduce
with
tht
(Figures
by the perchlorate
however,
been found for
among thw hexavalent
no maxima.
for extraction
appreciably; complexes
relative
exhibit
of weak coqlexing
agent% such asOSOb2-, all
while
decreases
and hexavalent
with
of inextract-
PI(IV) > M(VI) ~~
actinides
U(VI) > Np(VI) > PU(VI)â&#x20AC;&#x2122;GS The tetravalent
cations
for extraction
ha:
actinides:
tetravalent
Pu(IV)
n-or:
(VI) stat{!
of extractability
states of the
For the
Am(III),
of Pu and U.
> M(V).
the
149
of Np from Pu and U
of Np(V), or stabilizat:.on
M(III)
actinides
and Harmon;
and many other
Separation
by extraction
oxidation
anJ TBP
from Al(III),
Zn(II),
of Np to the
stripping
Np(V) followed
by Schneider
separated
Na(I),
oxidation
The following the
completely
Fe(III),
either
solutions
19.
of TBP extraction.
and subsequent able
of aqueous
of
such as Al that
partially
negate
Distributicm
form the
TABLE 19 EXTRACTION
1on
Coefficient
DATA FOR TBP1bg
TEP (%)
Solution
Extraction Coefficient At 25째c
Am{III)
4.OM HN03
30
0.013
Al
4.7M
15
0.0003
Ca
4.7M
15
0.0003
Co{ II)
2.14M Co(NO,)l
60
0.002
Cr(III)
3.OM HN03
100
0.0001
CU{II)
3.OM
100
0.0004
Fe[II)
4.7M
Fe(III)
0.005
2.Cm4
15 12.5
Mg
4.7M
15
0.0003
Na
2.OM
12.5
0.003
Ni(II)
3.OM
100
Np(IV)
4.OM
30
3.0
Np{vI)
4.OM
30
12.0
Th
4.OM
30
2.8
Pa
4.(M4
50
2.8
Zn
2.OM Zn@03)2
12.5
0.0001
Ru
2.OM HN03
30
0.1s
Zr
2.OM
30
0.09
Nb
2.OM
30
0.03
Rare earths
2.OM
30
0.02
Pu(III)
5.(X4
20
0.012
Pu(.IV)
5.OM
2G
16.6
Pu(VI)
5.(IM
20
2.7
U( IV)
4.OM
25
10
U(VI)
4.M
25
23
HM13
2.OM
30
-63-
0.003
0.00006
0.26
.,
HMO,* mola/4
Figure
5).
Dlstrlbutlnn of â&#x20AC;&#x2DC;Tetravalent TBP.-Kerosene
Coefficients Actinfdes from Nftric
-64-
for tte Extractlm by 19 ~ol % Acid S~lutforl. l&5
~lgure!6.
Dlstrfbution of Hexavalent lBP-Uerosene
Coefficients Actinlde% from Nitric
-6S
-
for the Extraction by 19 vol Z Acid Solutlon.â&#x20AC;&#x2122;G:
coefficients
for Np(V] and trivalent
lower171
than
for
tetravalent
actinides are appreciably
and hexavalent
actinides,
For Np02+: ‘2+[aq) For analytical atta~ned
+ ‘3
[aq)
applications
in less
than
The extraction
with
five
properties
Np have been defined. the order
are given
SUb!3t~ltUUIItS in
strongly the
the alkyl
depressed
length
chain
for up to eight
hexavalent
actinides.
extraction generally
the
the butyl
for series
(R(RO)2PO)
ox:~de (RsPO).i72 of some
trialkyl
et a2~76 f’ound that
Sidda1173
in the phosphate
carbon
electronegative and phenyl,
found that series
made little
atoms for tetravalent of branching
increasing
and
the alkyl
chain
of U, Np, and Pu, but to strongly
The extraction
same as that
methods
20.
The effect
the extraction of Th.
F:w separation
chain, such as, chloride
difference
to increase
cmganophosphorus
wilh various
the extraction.
of the alkyl
is
good mixing.
for I.he extraction
actinides
Burger t7b*175and Petrov
equilibrium
((RO)SFY1) < phosphonate
coefficients
in Table
volume:;,
et aZ. wm:king with
(Rz(RO)PO) < phosphine
and hexavalent
phosphates
however,
Higgins
‘The distribution tetravalent
with
“ ‘W’02 ‘W3) ‘Tap] (erg)
of many >ther
to be phosphate
< phosphinate
small
minutes
compounds have been studied;
found
+ ‘Bp(org)
mechan~sm of these
for TBP,
“66-
but
the Solvstion
is
depress
cimapounds is number
is
not
TABLE20 DISTRIBUTION COEFFICIENTS FOR THE EXTRAC1’]ON OF TETRAVALENT ANO HEXAVALENT ACTINIDESUITH 1.9MTRIAI.IYL PHOSPHATE/ n-DODECANE FROU ZM HNO! AT 30°C7’
Extractsnt
Th —— 2.9 2.4 2.9 4.2 3.0 2.4
Tri-n-butyl phosphate Triisobutyl phosphate Tri-n-amylphosphste Tri,imamylphosphste Tri-n-hexyl phosphate Tri-n-octyl phosphste Tri-[2-ethylhexyl) 2.s phosphste Tri-[2-butyl] phosphate O*4S Tri-(3-amyl) phosphate 0.22 Tri-(3-methyl-2-butyl) 0.18 phosphate Tri-\(4-oethyl-2-amyl) phosphste
0.047
Distribution Coefficientsa .—— Np(IV)b h(IV)O J(VI] Np(vI)~’ PUNI) —— —. —— 3.5 26 15.6 16.1 3.2 3.4 2.? 15.9 22 11.8 4,1 19.3 32 15.6 4.2 4.4 18.9 17.8 34 4.7 4.s 20.0 38 1S.6 3.6 3.9 1s.7 33 15.3 3.4 23
5.7
4.3
25
58
4.9 3.5
28 18.1
42 49
3.(?
24
47
25
S.4
3.5
22
38
24
4.9
a. For traceramountsof the givenelements. b. The aqueousphasecontainsO.OIMFe(?WzSO~)t. u. The aqueousphssecontsinsO.OIMN8NOt. d. The aqueousphasecontsinsO.OIM (~)2Ce(10,1{.
- 67 -
4.6 5“0
necessarily the same for all
elements.1”
A method with mono[2-ethylhexyl]orthophosphoric acid in
contact with 12M N(21+ O.lM hydroquinone separating
Np(I’!/) from U(VI),
trivalent
rare
the other
cations,mlO-l;
contact
earths.
followed
The K value
by multiple
coefficients
Am(I[I),
Cnl(lII),
for and
for Np([V) is ‘V103,and for
thus, separation scrubbing
K. Kimura178 has determined tion
Pu(III),
has been effective
the acid
i:5 attained
by a single
of tl~e organic
pha:$e.~’~
depend{mcy of the distribu-
for many elements
extract~ti
by SO vol%
bis(2-ethylhexyl)orthophosphoric acid(HDEWP: from HCl solutions (Figure
7),
These data
offer
the basis
for
separating
Np from
many cations. The distribution coefficients of Am(Ill:], U(VI[) in HDEHPfrom HNOo are given continuity probably
in the Np(V)
curve
in Figure
at high acid
due to disproportionation
Pu(IV), that
acid
than
extraction.
180
is
Np[IV] and Np(V[),
Np(V).
however,
of the Np(V) was reduced
by a single
NP(V), and
The dis-
concentrations
has been separated
and Th(I’V) by HDEHPextraction;
a few percent
separated
nitric
8.179
cJf Np(V) into
both of which are more extractable Np(V)Iin dilute
Pu(IV),
from U(VI), there
was evidence
to Np(l’V) and not
Kosyakw et C[ZjT9 used
HWH!P to purify Am(III) from other actinides in higher valence states and,to accomplish their mutual separ~a:ion.Am(III), Pu, and U were extracted from O.OIM HN03 after -68-
stabfl:[~ation
of Np in the
Fr
Elrl$l c
N
Figure
7.
Extraction in Toluene
+ DFP
wlks.stusiqmM4allW~da&
*T1 *EN s
DatJ#TMi=ui. Ma of EMhmurJ,
--CABLMtAIXCAMabmwl#. Scrlibitq
of Elements frcm as a Function cf
-69-
Xd
HC1 Solution by 50% HOEHP Acid Concentration.17*
-.
?
Log [HN03] Figure
8.
Extraction (Isooctane
of Various Actinicl~!s into o.5MH(lEHP diluent) from HNO:I Solutions. lTg
-70-
pentavalent
state
with
sodium nitrite.
to Np(VI) and extracted and recovered
to Pu(III)
f-
Chudinov
and
phase
by washing
the HDEHPwith
and recovered
U(VI) was recovered
Yako*~lati’-o step
with
to HP(V)
O.lM HNOs.
W HNOs and Pu was
by back extraction
by back extraction
HDEHPas a preliminary
oxidized
HDEHP. Np(VI) was reduced
from the organic
Am was back-extracted reduced
with
I@(V) was then
with
3M H?U)9*
w:.th lU (NH~)z COs.
extracted
IJ and Pu from Np(V) with
in the colorflbetric
determination
of
of several
actinides
Np(IV) with Arsenazo(IJI). Peppard
et a2!7”’D’al
studied
by mono-2-ethylhexylphosphoric (Figure
9).
was ~103, Gindler
larger
et UZ.’B2 used this
coefficient than
the non- “:etravalent
conditions
10).
~ey than
White and extractive
Pu(IV),
ROSS183
properties
fission
phase
by
in a great
the d:Lstribution
coefficients
and U(VI) in I{zMEHPfrom nitric
are generally
those
re:;ulting
studied.
coefficien-:.
Kosyakov et U2. *79 dete~ned Np(V),
species
2’GPu for
to the aqueous
phase,
in the distribution
of Am(III),
for Np(IV) in 12M HCl
method to puvify
of TBP to the organic
reduction
(Figure
(HzMEHP) from HC1 solutions
The Np(IV) can be returned
counting. addition
acid
The distribution 104 times
the extraction
higher
:For the
acid
same aqueous
for HOEHP. have written
a general
of tri-n-octylphosphine
-71-
review
of the
c~xide ~m).
‘R17
-1
Figure
9.
ExtractIon H2MEHP in
of some Actinide Cations Toluene as a Funct’on of
-. 72 -
into 0,48M HCl Concentration.177
6.a
5.0 4.0 3â&#x20AC;&#x153;0 $3 ~ 2,,0 d I !,0
o -1.0 -2.c)~.L--J_. -1.0 -0.5
0
0.5
I.()
LAW[HN03] Figure
10.
Extraction of Various Actilnldes into 0.2!4 H2MEHP (Isooctane diluent) From HN03 Solutions.~79
-73-
Extraction data for Np and other actinidos into TOPO have been sunmnarizedby Weaver and Homer. leb Extraction with methyl isobutyl ketone (hcxone} is based on the solvent power of hexone for the covalent nitrates of the (VI] oxidation states. Hexone was used for large-scaleprocessing of irradiated nuclear fuels (“redox”process) but has been supplanted by other sol,ventsboth in plant and labflratoryapplications. A twocycle extraction system for the separationof neptunium from uranium-fissionproduct mixtures has boon given by Maeck.195 Hexone extraction of Np(VI] from acid-{il:ficient Al(NOJ)S was followed by TTA extraction. Excellent separationfrom U, l%, W, and Zr was attained. Also, Np has been separa~tedfrolm Pu and La. Np(VI) and IPu(VI)were produced by oxid~tion with KBr03; both were extracted into hexone from an A1(N33)3 solution. Back extraction with an aqueous sodium nitrite solution yielded Np(V) and Pu(III), neither of which is soluble in hexone. The hydroxides were precipitated and dissolved in nitric acids and ferrous sulfamate was added to give Np(IV’Jand Pu(III). Np was extracted into a solution of tributylaminein he>,one,leaving the Pu in the aqueous phase.*2g Extraction coefficients for ions :.ntohexone different
aqueous
from several
compositionsare shown in Table 21,
Dieth:ylether quantitativelyextra,:tshexavalent Np, ?%, and Am from salted solutions containing a strong oxidant (Table 22).la6 .“74-
TABLE1!1 EXTRACTIONCOEFFICIENTS OF VARIOUSSOLUTESINTOHE)(ONE AT 25°C1° Salting Agent (M) Al(N3s) s 1.3 1.3 2“0 2,0 1.3 1.95 1.3 1.s
HH,HO,
Al(HO$)S A1(HOY)S
tai,tq
0.7 1.0 1.5 1.0 1.0 1.0 1.3 1.4 8 8 11.1 ill 11.1 2.0 0.s 1.0 2.0 4.3 8.7 11.0
Nc~-
(M) 4.0 3.9 6.1 6.1 4.4 6.3s $.4 S.O
2.6 5.4 JI.5 :;. s :;.2s :i. 1 4.1 4,,6 E.2 8.2 11.6 11.6 11.6 6.3 1.8 3.3 6,3 4,6 9!0 1~ 3
!wd!!!l 0“1 0.0 1.7pH 0.1 0.5 0.5 0.5 0.s
Extraction Coefficient 0.02 <0.0001 0.011 0.0003 2.1 0.0018 1.5 <().001
0.5 0.4 0.0 0.5 0.2s 0.10 0.20 0.4
1.7 0.82 1.1 0.009 0.01 0.10 0.12 0.10
0.2
0.004
0.2 0.5 0.5 0.5 0.3 0.3 0.3 0.3 0.3 0.3 0.3
0.0005 1.7 9.8 0.14 .50.0 0.1 2.0 30.0 0.18 2.0 14.0
—— of all solutesis 2 g,f: a. Concentration b. h-emitting 144-daycoolingperiod. fissionproductsaftel’
7s ..
TABLE22 E.KTRACTION OFNEPTUNIIH, PLUTONIM,AND MERICIW
INTO VARIOUS SOLVEWS \
—-.——— Aqueous
—— Solvent Ethyl
ether
1!4 tiW3; bN
Dibutyl carb
DBBP,= .Jot
!ko2.
!P.u!l
Extrm:ted
!!LQIQ
9
17
12
70
HNo,
17
6S
!2
89
tfl’o,
1-7
23
)1
8:
23
48
1’9
95
co
w
Iiuws
91
Hm,
15
ca(K)$)*;
2.4M
0.6)4 w, o.oSN
11
0.3
~~
.— High
efficiency;
b.
Np(IV)
c.
Dibutyl-butyl
unstable
d.
Dibutyl
ether.
WQ!!l
W
?i.4M ca(ND1)2; a.
w a
dlM HND,
85$
(xv)b
IWbW,
HNos
%
D~,d
~
ml
7
i no 1
sat
Phase
no in
value
given.
W40J.
phosphonate,
@BE, * i’th
DBBP. 15%
CCIQ.
-76-
41
100
Other
elements
SC{III);
that
extract
P, Cr(V1],
As(V),
are partially ferrous
extracted.
ion and urea
strongly
are Ce(IV),
Hg(ll), After
T1[III.1,
diethylether
further
Distribution neptunium,as carbitol
separates data
for
a function
with
dilute
are added to reduce A second
Np[Vl; IWNOS is added for salting.
Np(IV) fron
several
of nitric
of the acid
and
and Bi[III)
III(W),
back-extraction
orhydrazine
Au(III),
acid,
Np(VI) to
extraction
with
U(VI).127~i@’ actinides,
including
concentration
into
dibutyl
are reported.l”’oloo including
Amine extractants, secondary,and with acids
tertiary
mines,
long-chmin and quaternary
to form an ion-association
the organic
The mechanism
phase.
alkyl
or aryl
amine salts
primary, react
complex which is soluble is illu:itrated
with
in
a tertiary
amine: +
‘3N(org) A-
be either
may
acid. anion
“ ‘+ (aq)
+ A (aq]
a simple
anion
+ R3NH ---- A-
(org)
or the an:.on of a complex metal
The complex may undergo a further reaction with another in a
❑ anner
R3NH+ .-. The higher and U.
analogous
A (erg)
to anion
+ B (aq)
araines are excellent
The advantage
the greater
stability
solutions.
The amines
exchnnge.
+ ‘9NH+ ‘“.- B (erg) extractanl:s
of amines
over
to radiation are usually
-77-
for Np(IV),
orgamphosphoms and hydrolysis dissolved
+ A {aq) PuIIV], ccqounds in radioactive
in an organic
is
solvent
(xylene,
extraction,a
s-1
amount
selectivity
solution
depends
of the aqueous
phase.
The l’elative
aliphatic
extractztiility
~nium
> tertiary
> secondary
is reversed.
the
of the umine and the composi-
The extrsctive
solutions
the squence
phase.
on the structure
and chloride
varies
pfwer of the asdncs
in the
> primaryJ’$i
order
in
Quarternary
from H2SOS solutions,
The distribution
l:oefficient
of tetra-
and hexavalent actinides from IiCland HW~ acid solutions
decreases in the
sequence
Pu ~ Np > U > P- > Th.
Keder et al. 190 have rqorted several
actinide
elements
solutions
acid
with
xylene
(Figures li, 12, and 13).
The tetravalent ions amine concentration,
show a second that
Extraction
for
state)
from
(TOA) cliluted
with
power depende,tce
the extracted
on the
complex
involves
of Np(IV)mIci Np{V’[) with
(TLA) from nitric
of :Iiquid-liquid
coefficients
tri-n-octylamine
indicating
two amine molecules. trilaurylamine
distributim
(more than one oxitiation
nitric
review
●chieve rapidlphase
is Np(IV) > Np(VI) > Np(V), although
nitrate
valent
TCI
[3 to S vol%) of a long chain
is added to the organic
of Np in nitrate
tion
or chloroform).
and to prevent formation of a thixd ph8sB during
separation
alcohol
benzene,
acid
extraction
with
is reported.
1’]*1$2
high molecular
A
weight
amines has been publi:nrci. lg’ Np(IV) has been separateo fission products
by extraction
frm
U(VI),
1’u(III),
of Np(IV) info
-78-
Am(III),
tri-iso-octyhmine
and
o
b
P---d
1.0
Figww
11.
I
The Extractfofi of tlm QwIrawhnt Acti nt& llftrat8s by 10 vol %TOA In Xylem. ;â&#x20AC;&#x2122;s
-79-
“r-vl t
b
lo4
no+
m
02468
Ffgurt
12.
12
14
of tktlcxavalent Actfnfdk The Extraction Nitrates by 10 vol Z TOA in Xylene. ~g’
-80-
Ioo#
w-
——
-1 AQtJoan Hrws, M
-81-
(TIOA) in xylene ferrous
from aqueous
wlfamste.
SM nitric
For further
organic solution was scrubbed Sul.famate.
Final
extraction.
19’’~”s
extraction
with
Ihe ~was ntaber
with
~ni~
this
tetra
system
(Figures
are umc
the
than
the order W8S primary
primary
>> secmdsry
methods
ext?actsd
separ~~ting
from
tradcnamc
The torn extraction
as c~ared Rohm ●nd
-a2-
than
TOA Np(IV]
actinides
:\ystem.
In guneral,
from mlfate *n)’
~re
solution Proce”
for U and Pu,
sndi
for Np separmtic}n.es”i’]~ze’
(ditwntaj.
of
into
JH-T in XYlonc.
~Jne*20Q
potential
(or depressed)
(diluents)
various
from sulfuric
have been reported
offer
Mixed &xtruotunt8
~’gfstered
tetravalent in this
~ tertiary
these
enhanced
for
coefficients
of Np(IV) and Pu(lV)
for aciinuextraction
extract~nts
the
amine “Primene”*
durcs
to denote
fron
and the hemnmlent
were strongly
of extraction
also
for a large
is much more extractable
same conditions,
extractable
by the
data
and a proc~lure
the distribution
Pu(lV)
Np(IV) ●nd Pu(lV) ●cid
in xyltme.
Np, Pu, and U from HICl solutions
14 ●nd 1S).
and U(IV) under
:litrata
has been SWpOrtaX1.isC
has reported
- and hexavalcnt
2*~AJSby
anmonium c~~ds
solutions have been determined,
a TTA
[i# > 20] froa 0.1
O~stributilm
in quaternary
ferrous
with
frm
Np(IV) was extracted
O.lM tetraheptyl
of elements
Kedertiss
SM HMO$containing
239Np has been separated
TIOA.*g’
containing
the neptunium-bearing
of Np was ●chieved
~2000 in lMNNO1. l$’
Np and Puuith
solution
separation,
purification
to IOM HPKlgwith
acid
synergism
is iusod
of metaks
by mixed
to extraction Mas
Co.
by each extractant
Jd-L-Ld_d.-s 024
Figure
14.
SOK) Hcl. l!
ExtractlonoVU(IV) and NpI(IV) and Pu(IV) b{$!,m Tu frm MCI Solutl on%
by 10X TM
●
“8s
-
too
10
w’
E.. ./ 2
Figure
15.
4
6
10
ExtractIon of Hexavalent U, NP, ml with 1.0% TOA Pu fmm HCl 5olutlon in Xylene.1’9
-64-
(diluent)
taken
under
term synergism
the
understood. Although
separately.
A reviw the
reported
sre
reported
and fission
products.
for Np.
lM HIP04.
More than
other
elements.
gm
activity
component
O.lM l-phenyl-
several preted
other
on the
phosphate in terms
structure,,
of diluent
Np wa~ extracted
interaction Figures
mixtures
TBP and tetrabutyl~nium
were used
with
the
inflwunce
of polarity benzene
to
zO.1% of of the
in two-
and carbon
of Np(IV) ●nd Np(VI) cooplexes
of the
The results
complex
between
npucies,
complex
are
inter-
the diluent
and diluent,
16 and 17 show t~~e effects
on the
of curium
by measurement
of chlorofl}rm,
size
quantities
239Np,
extraction
of the
daughter
and Cm in O.SMHNO, and
and amine extracta’nts.
dipole
factors.
99% of the
●ixtues
its
have
3-methyl-.4-benzoyl-pyrazolon-S
Mb, Cs, Ce, h
has d~scussed
attention, only
(TEP) in benzene
of the extracted
diluent
tetrachloride
large
The ““AR was determined
Taubezog
by Marcus.*”
Lebedev et a2.202
containing
Np(IV~ from Zr,
described
not completely
2“3Am through
(PMBP) and 0.2SM tributylphosphate separate
is given
con~iderable
to determine
2Y9Mp in solutions
l:omplex,and
subject
has received
a procedure
product
is diverse,
of this
subject
a few examples
The rangl~ of phenomena
and
of variation
dis+ributicm
of Hp(IV) and (VI) into
nitrate
nitric
-8s-
frm
●cid.
with
.,. ..
.
“--E L
: “c.
/
4
d
2 0.1 --- v
k
0
Figure
16.
002 OA 0.6 0.8 Mds Fmctiom of Dilusnts Heptunlm ExtractIon W HNOS Into Dlluent
-a6-
——
I .0
with TBP from Mxtures.2ss
Mol. Fructions Figure
17.
d Dihmts
Of stri button Coefflc<lunts fclr WO( IV ) Extraction with 10-2N Tetrat@ylkmontum Nitrate from 3M NtKIs Using Mixtures of Different Dfluer~ts.203
-87-
c.
ION EXCHANGE hhny variations
of ion exchange
are used for separating
14pfrom other ions. Np ions in dilute nineral acids with no strong completing ions are sorbed by strongly acidic cation exchange resins,
such as sulfonated
of cations
to be sorbed
increasing
charge
of sorbability >
on cation
and decreasing
on cation
~22+
polystyrene.
In general, the ability
exchangers hydrattd
exchangers
for
increases
radius. .Np is
Thus,
with the
order
Np(IV) ~>Np(III) >
All Np species are sorted at low acid concentra-
W}*
tions and eluted with high uoncentraticms of mineral acids; elutio,~of NpO~ proceeds first and Np(I\) Ss last. Some anions form neutral or anionic complexes with different oxidation states of Np, so that Np may be eluted by this mechanism. Both Np(V) and Np(VI) are slowly reduced to Np(IV) by common organic base resins. For this reason and because cation exchange of Np(IV) offers limited selectivity in the separation from other multivalent cations$
this
method has not been used ~idely for analytical
applications. Anion exchange
is
one
of
the
techniques
mc)stuseclfor
separation of Np in analytical and process applications. The method is simple to perfom and yields excellent separation from many other elements, including most of the fission products. Ion exchange ha~ been the subject cf many reviews. The books of Helfferich,20° Samuelson,zos Anrphlett,20&and Rieman ant
-88-â&#x20AC;&#x2122;
are good references
Waltonzo’
ion exchangers.
Other
Korkisch,20s’2il
and Faris
Anion Erohunge. complexes species
that
are
provide
anionic
adjusted
ions, all
to 55*C for
this resin Zr,
Greater
anion
treatment bed.
exchange
Ru, Pa,
is washed with earths,
most other
cationic
contaminants.
separmted;
howevez,
washing
6UW3-O.05M
with
to prevent
rare
femous
:~ sample
with
-09-
over
a
have been
containing
Np
of Np(W~)G2-
The solution
sufficient e.rcess
Fe(II)
e.~cessive strong
to
gassing
nitric
acid
is heated
Fe(III); in the to remove
elements,
‘l’h(IV) and Pu(IV) 5 to 15 bed volmes hydrazine
that
sodium nitrite
U, transplutonium
sulfamate-0.05M
in the chloride
is added to ensure
to Np(IV1.
is necessary
Fe, Al,
of Np is attained
optimum :\orption
and oxidize
sorbed
111.
cycle,
or treated
elements.
fozm strongly
concentrations
sulfamatc
is reduced
anionic
of many other
of many elements
sultlmate
The resin
Massart,20e
the
:;ystem than
in Figure
to 0.05M ferrous
the
of
and chloride
resins;
sep:ltation
and nitrate
given
30 minutes
all
al:;o
in the nitrate
acid
Np[V) and Np(VI]
to react
actinides
to 7 to 8M HNOs for
and 0.01
by anion
coefficients
Data are
include
nitrate
from the cations
elements
In a typical
forms anionic sorbed
of the
of nitric
reported.212
is
strongly
The distribution
wide range
end applications
and 8uchanan. :10
complexes.
from most other
theory
of ion exchange
Np(IV)
state
chloride
system.
reviews
separation
The hexavalent
to the
and
are not of 5 to
reduces
Pu(IV)
to
I
Figure
18.
Sorption of by Strongly
the Basic
Elements Anion
from Nitric Acid Exchange Resins.212
Solutions
Pu(III),
which
HCl removes
is removed from the
Th.
and particle
The Np is eluted
size
from other
cations
Macroporous
anion
of the
resin
as well resin
column. with
influences ofthc
superior
W
0.3M HNOg. Cross-linking
greatly
as elution
is
Washing with
the
separation
Np. i52’zi3-215
to gel-type
anion
resin
for
separation
of Pu from Np. 21sa A number of similar
procedures
variations
in acid
of semicarbazide
concentration
or aminoguanidine
for
The separation and Pu!IV)
and substitution
hydrazine
of tracer
in nitric
acid
with
have been reported. amounts
by anion
of Np(VI],
exchznge
Th(IV),
Am(III),
has been reported.21G
The feed was adjusted to 7.2M HN03-0.054 NaN02 at 50”C to yield Np(VI) and Pu(IV).
After
column was washed with then
with
to elute cations
sorption
7.2M HNOg to elute
4M HN03 to elute Pu(IV).
Other
Th(IV),
completely
Also,
in 7.SMHNOY using
ascorbic
acid
the 2+ and Np02 ,
with
0.35M NN03 of these
of Np probably
Th([V]
The separation
separated.
Am(III)
macro quantities
separation
to Np(IV].
l-X4 resin,
and Finally
work with
has shown incomplete
of some reduction
on “Jowex”
because
and I%(IV) were not
o:: Np from fission
reductmnt
is reported
products by
Ichikawa.217 Radiochemically high purity chloride
metal
anion
pure with
exchange
The distribution range
of hydrochloric
Np has been p::epared
one nitr~te cycles
exchange
production cycle
of
and two
successillely.zie
coefficients acid
anion
for
of mnny elements
concentrations -91-
over
a wide
have been reported.
These data
are used
exchange
(Figure
chloride
anion
to design
systems
:forchloride
Np, Th, and PU are
19).*2*’zi9
exchange
separation
by sorbing
the
of Np(IV) and Pu(IV) in 8 to J2M HC1.
anionic
:}eparated
anion
by
chl~oro-complexes
Pu(III) is eluted with
NHI+Iin 8M HC1, NH20H-NH41 in 12M HC1 or Fe’;12in 8MHC1; Th is not retained; and Np is eluted with 0.3M HC1.iss’220 Distribution data for 65 elements on “Dowex’’*l-X8from 2 to 17.4M acetic in water
acid
have been reported221 (Figure 20), E)(~Fllesof several
separations including U and Np are
given.
Distribution data
for
60 elements on cation exchange resin from 1 to 17.4M acetic acid in water have also been reported.222 With !lp(VI)
in 7.9M HC?HSOZ,
equilibrium was not reached even after 40 hours of mixing.
A method to separate and determine Np, Pu, U, Zr, Nb, and MO in ❑ixed fission products by anion exchange with HC1-HF solutions has been developed.223 Trace quantities of Np have been separated from macro amounts of Zr and trace amounts clfNb by elution with HC1-HF solutions.22° Also, HCI and HF solutions have been used to separate
U, PUB and Np from each other ard from alkali metals,
alkaline earths, rare earths, trivalent actinides, Al, Sc, Ac, 7%, Y, and Ni (Figure 21).225 Controlled elution with a series of solvent mixtures was used
to separate Np, Pu, Zr, Nb, Mo, Tc,
Te, and U from fission products.22G The chloro complexes were sorbed on anion resin and sequential washes with 12M HC1-NHZOH-NH41(PU)B 10M HC1-Aq H20z(Np), 9M HCi-Aq Hz02(Np and 2r), 9M HC1-ethanol (l:i, Zr), 6MHC1-ethanol (1:1, Nb), ethanol-lM HC1(4:1, Te], ●
Registered Trademark of Dow Chemical Co. -92-
I u)
M
-F4
w. p
I!iil D1 ‘-J
1
I 4
4a.1
l:+ .;, ,[.
WI
L$lRI“w km).
w’..
4-4
1!1
Ei34 HJ# ,,
‘w’ L pd#i
ULlIiLi.1
d
Ewu Sorption
cl
*I
.,
:
ml ::5.. m
Em-1 lEm
20.
m.
,
id Q
~E Cdq .,
Figure
5
tl
m n i
%
u
ZI+I.1
w
0
EIMlll ~.ElEll E3fll fill Eilll *. km -.Bil Kit!! Eil Eliil kill NM
@1“
I
r
w
IalIEwF#l H EfElEEEw
81
EiEili of
the
Elenwnts
from
Acetic
Acid
Solutions
by an Anion-Exchange
Resin ?2J
T—-----71 4
k-
I
1
!50”
Elu@nt W&moo column
Figure
211.
Uraniun-Neptuni uwPlutonlwn Exchange (“bwex” 1-X1O, x 3 cm Column). **s
-9s
-
VdUCWB9
400
Sel~aration b y Anion Nesh, 0.25 cm2
ethanol-W
IK1(4:I,
Other
literature
af xp,
teristics
with
‘Skuex”-2
acid
fm
“lbuu#-2 hut data
Sp ukth
were
of
were
a study
data
Separation
ofSp
separations
Np in 0.1
~y~t~s each
given for
wru
Equilibrium
frtmCs
charac-
●n’d ~b~h
Imos,
pss~ble
and
lnclwl~ng
the elution
of
EquiIibri~
summarized.*”
elements
resin.
data
bmsed on wre
8iven
to WN NtPO. with attained,
andleuas
erratic.~a’
has hem
u~th
resin.
CO concentrated,
separated
Pa elut{ng
clution
included
and 4M tMls(Tc).
PU, II. Pa, WJ Zr in 1~1,
da:a
ndmr
a
O.IM Kl(ll)o
has
anion
O.lV
eqvilfbrifor
*),
fmm
first.’”
S!UIUl
Pa by elution
Separation
uith
has also
hem
an~on resin, in which
frm
1231 K1-O.5N
W
by
achieved
case Sp elutes
f~rst.zz* !JJ(IV) Sa2CD1
●nd elutod
Np(Vll]
a: (x:.z”
soluble
complex
was attributed
uith
fores
.Sovikov
elmts.
quant~tat~vely
haz been sorbad
lhe
W*CI
stahlc studid
as a
to
the
dilute
mlkal~nc the anion
poss~ble
sorption
or
has~s
of
-%-
fsxm O.IN
MC1.Y’O
s01ution9 exchange for
was irreversible redxtion
on ‘*R’”-l
as sk behavlw
separation for
the ~(~11]
all
Ion.
:+OS’of
this
from other experimts;
by the
resin.
this
An anion exchange method using the nitrate system has been reported
for
removal
of Np before spectrochemicaldetermination
of catioinicistpuritiesz]z(Procedure23, p 200), In several or ignited
reported
after
instances,
use in nitric
Tlw!se ●ccidents
are thought
of the exchange
resin,
presence should
heat.
of
col,un
acid
should
to the
should
reduced
reported
for
frou
a
cation
the
by elution
di:tedto the hexavalent state on reduction
exchange
has
lh(lV),
been
and Zr(lV).
in stronji
type
in the
form should be
nitric
wlmn high
state
resins
acid.
levels
Y. A. Zolotov
and
of Np(V) ●head of U(~’1)with IN MNOj
with
for partial
Np was
hove been
of Np from U, PI),and
form. bmsate.
to Np(V) by the resin.
used
and Np(V) are
separations
of $ip.
separation
have had limited
both Np(uI)
Several
in the hydrogen
dqpended
skeleton
reaction
and temperature
because
resin.:Sh
reported
resin
of the
be <8.SM, a~~d flow to the
acid
Np separations
for the pentavalent
products
fissioc
~olutions.233
in the col~.
S1OU1Y by the
D. Nishanov235
exploded
in the nitrate
particularly
cation &Ywhf.znge. Sulfonic
applications
resin
not be interrupted, are
ni’:rate
spontaneous!
<60*C when used
concentration
of radioactivity
or strong
in the dry state, ●t
exchatn:le resin
to be due to nitration
Anion exchange
controlled
The nitric
acid
leading
not be stored
carefully
anion
separation
ox~d~zed
-97.
Np was initially oxiSeparation Also,
of Np
cation
of Np from Pu(IV),
to Np(V) in dilute
nitric
acid
before
sorption
on the resin,
but a fe~rpercent of the Np(V)
was reduced to hlp(IV) by the “Dowex’’-5OWrosin separated
from the other
The distribution detmmined for
coefficients
for many of the “Dowe~’-5G resin.
elements
were
Conditions
of U(VI) and Np(IV) and separation of Np(IJ’)and
Pu(III) were given methods
cations.23G
in 0.1 to 12M HBr with
separation
and was not
(Figures
fcm Np could
22 and 23),
be devised
Mary other
separation
from the distribution data
(Figure 24).237 Np and Pu have been separated
by elution
from cation resin
with HF after reduction to Np(IV) and Pu(III) with S02.238 Np(IV) was eluted
first
with
with
0.5M HF.
with
HBr follGwecl
Also,
Pressurized at
0.02M HFZ3’, and then Np was separated
tory
separation
elution
development
separations for
of trivalent
and with
highly
over
of this
range
type
radioactive
a range
for
chromat~graphy
exchange
on cation
resin
has been very useful
elements
quantities,z~~
both
Although
Np are reported,
in the
labora-
no specific
the m~ethod is useful
solutions.
data
for many of the eleme~ts
of hydrochloric
of perchloric
from Pu by cution
acid
actinide
macroscopic
Distribution
was eluted
by TTA extraction.2’0
70 to 90*C with a-hydroxyisobutyric
for
Pu(III)
acid
acid
concentrations
concentrations
2S and 26).1$’ -98-
on “Dowe3@’,-50resin and also
over a
have been reported (Figures
a-
Smp18
9M WI 9M HBr ,,, .,,.
o
.44J-.-JQ 6 8
~
C)-2
m
Column Volumos
Figure
22.
Separation (“Oowex”
of U(VI) and NP(IV;) bY Cation Excllan9@ 0.2 cmz x 2 cm Column@ 25 °}?37
!iO-X4
3 -m
Sarrrpk
+
6M HBr
9M
HBr-CL2M
HF
2 ~MfJ(lv)
I
t,
o
,{ 0
4
8
12
-EkJ#..
Column Volumes Figure
23.
Separation
of Pu(III) and Np(I\) by Cation Ex$~~nge (“Oouex’’5O-X4, 0.28m2 x 3 m COl~~, 600).
-99-
t
Figure
24.
Sorption
of
the
Elements
from
tiBr
Solutfons
by a Catfon
Exchange
Resln,2$7
Figure 25. Sorption of the Elemen:;8from HC1 Solutions by a Cation Exchange Resin.
I
I
Figure 26,
Sorption of the Elements from HC104 Solutions by a Cation Exchange Resin.23@
i!no~anio largely higher
Ion ticdzangera.
superseded
Inorganic
by synthetic
capacities
resins
exchangers
principally
have been because
of
and more useful physical characteristicsof
the synthetic resins. However, inorganic exchangers have the advantage of greater resistance to radiation dumage. The distribution
coefficients
zirconium
oxide,
of 60 cations, zirconium
including
phosphate,
zirconium tungstate, and
zirconium molybdate have been ❑easured.zbz have studied
the
separation
Np, on hydrous
Shafiev et al.2k3
of Np, Pu, and Pm on zirconium
phosphate. Np(V) is not retained while trivalent elements are readily eluted with lM HNOq. Pu(IV) containing
reducing
quinone.
agents
Zirconium
of Np{V). HF solutions
separation Tsuboya
on amonium
separating
molybdophosphale
The sequence > Np(V).
of so~ltion
These
demonstrated
0.5M HN03 or hydro-
the oxidation
columns
conditions
retained
than
-
(AMP) colunns
state
has been
is Np(IV] > Th[IV) >>
same woy.kers demonstrated
Np(IV) and U(VI] with a tung:;tic
is much nmre strongly
sulfamate
does not change
of Th, U, and Np using et aZ.247
with
of Np, Th, and U from HN03, HzSOb, and
The sorption
U(VI) ~> Np(VI)
such as ferrcus
phosphate
dete~ined.2b~”2”s
is eluted
103
loaded
with AMP.24G
in a HNOJ system acid
the
exchanger;
for Np(IV)
U{VI) from 0.S to 2N HNOS.
-
CHRWATMRAPHY
D.
C?w0watog3up@.
Emhwction
been applied TBP sorbed
to the
exposed
and used as the reducing
separation
on diatomaceous
initially
for
a similar
were required
Nitric
to prevent
Eschrich250
same system
used
the
of Np by eluting
with
has
with
:~hase.zho of
with TBP, and without
Other
workers2b9
of Np(VI] to
from some fission
products.
the
The order
It is probable
was
and found that
NF
to determine
100%
silica
treated
reduction
0.5 to 2M HN03.
and Np[VI).
then acid,
separation
separation
Np[IV),
vapor,
phase.
Np(V) and to improve
Np(V),
The diatomaceous
was used as the mobile
system
modifications
silica.
stationary
chromatography
of Np, PUB Am, and U with
to dimethylsilane
agents,
used this
Extrac::ion
oxidation
states
of elution
that
was
some reduction
of
Np(VI) occurred. 23gNp was separated of TM sorbed
on glass
much more effective adequate two
so that
isotopic
fission
than
batch
dilution
reported
products
and U on a column
extraction;
to separate separ;ltion
method gave recovery
Np frm
Zr.
cf ~3gNp from
on Poropak..Q impregnated
wi~h
lTA-o-xylene. Some workers wkth an organic
have used “Kel-F”* extractant
as the
Registered
tradename
ofM.
●*Registered
tradename
of Ou Pent.
●
or ‘~eflon”**
stationary
K. Kellogg
- 104 -
Co.
phase
powders coated for extraction
-
was
However,
was not necessary.
were necessary
252 have also
and activation
proclucts
The chzomn.~a~raphic
powder.251
separation
column separations
Wehner et aZ.
from fission
‘
chromatography nitrate
separations.
“Kel-F”
has !]een used to separate
passed through the bed. containing
Fe(S03NH2)2,
The method is very
:oated
the column wa:i washed with
thu Kp was eluted with
pure 23gNp when the weight
trilaurylamine
to 2M HN03 - O.lM Fe(SO~N}12)2 and
After
selective
with
Np from U, Pu, and fission
The feed was adjusted
products.
powder
.lMHN03
HzS04 - HN03.
for Np(IV) and has yielded chemically ratio
of U to Np was >1010 in the
feed?s3
The separation requires one to two days. A :imilar method was developed for the coseparation of Np and Pu from U.zs” PapeY C?uwmatograp)qf. elements with
Ac through
methanol,
Keller.zss before
in the column resulting
from U(VI) with
measured
Rf values treated
the
[IV)
reduced
of the bi~nds. with
12M HC1-butanol
good separation
and
of Np(IV) from
Np(V) was separated
Rf values
for
ele:~ents
of mineral
with
.~cids with
atomic alcohols
applications.
for Np(IV), with
by
as developer.
96 in mixtures
analytical
tCV03 or HC1
Np(VI) is slowly
>lM HC1-butanol;
2M HC1-ethanol
90 through
and discussed
paper
with
Also,
for
Np(VI) to Np(V) or
separation
from III(IV)
mixtures.
U(VI) was attained
because
in poor
was separated
>8M HN03-butanol
Clanet2sb
to reduce
the separation
of either
Rf values
have been determined
and butanol
It was necessary
Neptunium(IV)
chromatography
Am in many mixtures
ethanol,
starting
numbers
Paper
TOA using
(V), and (VI) have been reported 0.5M HN03 developer
-
105
-
solutions
for
- . .... ... ,,. . ............ .
containing
LiNOS, NN~NOS, or Al(~s)3.
separated
for
different
actinides.zs’
treated water
the different
with (20:1)
oxidation Rf values
solutions
states
are well
of .Npand for the
were also
obtained
of tetrabutylhypophosphate
developer
using
The valuss
solutions
for paper
in acetone-
of nitric
and petrchloric
acid.2se Twelve fission
and neutron
have been separated fkuoric
capture
from irradiated
and methylethyl
isotope:;
uranium
ketone-hydrofluoric
including
with
aqueous
acid
mixtures
23gNp, hydroas
developers.259 Thin Layer (%rcxnatography. valence
states
Rapid separation
of Np from each other
elements
by thin
saturated
with
demonstrated.2
layer
powder
solution
has been
separation of the
transuranium
by gas chromatography
of their
chloriies
has been
The volatile
chloride
comploxes
were synthesized
60
were
at %2500C with
snme position
A12C16 vapors
carried
less
and Pu were eluted
experiment.
on ‘7eflcm’’-4O
O.lM tetrabutylhypophosphate
at %SOO°Cby adding
the
actinide
‘e
demonstrated.z
experiments
and from ether
chromatography
Gza Chrcwfatogq?ly. Effective elements
of different
than
into
out in glass
the carrier capillaxy
one microgram
in order
of decreasing
as lighter
Ianthanide
The retention
times
of W,
- 106 -
gas. colums
The maintained
of each actinide. ator~ic elements
Cm, Am,
number in about in a similar
U, and Pa are much
shorter; it is postulated that the tetra{:hlorides of these elements i~re
produced. The chromctogram is measu]’edby collecting fractions
of A12C16 condensate at the exit of the c:olumn. The actinide hydroxides are carried with La from strcxlglybasic solution and separated from Al. Then the actinide is deposited, anclthe alpha spectrum is measured with a surface barrjer detector and
multi-
channel pulse height analyzer.
F. .
OTHER METHODS
Volatilization.
Separation of more-volatile Np(IV} chloride
from PuIIII) chloride and other less volatile chlorides has been reported.261’262 The actinide chlorides were prepared by passing carbon tetrachloride vapor at 650”C over mixtures of pl.utoniumneptunium oxides or oxalates. The nepturium chloride sublimate was collected with a separation factor of’%3 x 103 for Np initially containing 4% Pu; the yield was w96%. Tie method is useful for obtaining quite pure Np where a quantitative separation is not ~equired.
NpFG is quite volatile, intermediatebetween UFG SLndPuFG. Separation was attained from UFG by co-scrption of the hexafluorides on NaF. Then the F@FGONaF complex was reduced, and the UF6 desorbect. After refluorination,the NpF:cwas desorbed.263 EZectrophore8i8.
Clanet256
has developed m electrophoretic
method on cellulose acetate membranes tclseparate the charged species formed by elements with atomic rmrnbers90 to 96 in 1 to
-
107
-
12M HC1 and HN03. Mobility curves have beer obtai:nedfor the acid concentrationrange for both acids. A large number of potential separations of these elements and the solution conditions are tabulated, Some of the separations of Np irclude !Jp(IV)ctr(V) from U(VI:);Np(IV) from Pu(IV) or (VI); Np(lV), (V), or (Vi) from Aml’”IiI) and Cm(III); and separationof the clxidationstates of Np. Electrodepoeition. to prepare
mOUMS
Although electrodqlositionhas been used
for radiometric measuremc!r~t, electrolys~lshas
not been used as a separation method. Ther(!has been one report that U, PtJ. and Np were separated
by electrtllysis
from HIWls by
var:yingthe pH. Optimum conditions were slultedas current density 7S0 to 1000 mA/cm2 with
a plating
volume of 20 to 30 ml.
Np is completely delmsited at pH :* 9, and
Pu and U are
completely
time of 2 to 3 hours
deposited
and solution
at pkl C6 ~md pH <3, respectively.2’*
Other workers using different media for ele~:trolysishave been unsuccessful in separating partial
separation
after
neutron
products
An analytical separation
exposure
were separated
abundance
by -ss
exchange,
extraction
l:ations
has been attained,
method has been reportlxi.
Mi808zkneim8.
sequential
Although
ac-:inicles.
from a number of comon
no useful separation
yields
Np from other
scheme Ih,is beer) described uhich
of the
of 1 mg of
●
elements fissile
and isolated
spectrometry
using
chromatography,
-
108 -
including dlememt.z’$
for determination solvent and
extra~ction,
prccipitution
Np renaining ‘The of isotopic ion methods.
VIII. ANALYTICAL METHODS A.
SOURCE PREPARATION AND RADIOMETRIC METHODS
Counting.
Because
counting methods are more :}e:lsitive than
chemical or spectrochemicalmethods, they ara the
primary methods
for identifying and quantitativelydetenaining Np. The two most common Np isotopes by alpha MeV. it
counting
are its
237Np ~d two major
If 237Np has decayed
can be dete~ined
daughter. gam
23*Np. 237Vp is uwally
for
alpha a period
by gama
2~7Np 86.6-keV
239Np is determined
6 months of its
from 233Pa lthich g-
by g-
$~t 4.781
of shout
ray spectroscopy
[f 2’:’Np is separated
:?ay, the
transitions
its
gains
and 4.762 or longer,
2y]Pa
h~as an 86.6-keV
ray can I>e counted
counting
determined
dimectly.
transitions
at
228 md 273 keV.*O The gross proportional
with
Liquid
●
of 23’Np
or plastic
nuclidcs
the percentage
are present,
surface
of the
with
barrier
●n
be used to determine l%- energy
b41
resolution
cout~ter.
with
a
If other
height
8111cws a detemimtion
of
counts attl’ibutableto 2:17Np. can be uwd
100$ ●fficiency
237Np in the
determined
●iphm pulse
detector
total alpha
●lmost
can
scintillation)
scintillationcounting
●lpha activity
nuclides.
activity
counter
●lpha-eaitting ●nalysis
alpha
presence
in giquid
-1o9-
to determina
gross
ard in many cases d
other
can
alpha-omitting
%C!intillmtion
if~ MOO KeV
as
coward
--ray detector
1S KeV for
to
spectrmetry or a Ge(Li)
coaxial
(228,
Ge(Li)
relative
Ge(Li)
have an energy
resolution
An o-y coincidence
the
which
coincidence
sensitivity
for
is
3 to
1S% for the
detectors
lower
determinating
(LEP)
efficiency. 237Np was
The resolving time of
as 8 x lCâ&#x20AC;?-6 sec.
method was developfd 237Np.2G5
determining
such Ge(Li)
photon
selectivity.2sâ&#x20AC;? was taken
A radioactivation
1.0 KeV) is much better
of 0.S KeV with for
2s9Np.
tw]ergyresolution of a
NaI dete~tor
low-energy
increased
1:0 determine
efficien:yof
The
method
system
a !la I scintillation
the
(about
to a 3 x 3 in.
ray.
developed
either
278 KeV),
detector
1.33-MeV g-
(Ietectors.
may be used
than for NaI (about 20 KeV). detectors
barrier
with
detector
For 23$Np gamma rays typical
surface
to increase
the
Thf!activation product is
short-lived 23@NP, which is determined by t:ountingits 1.0 MeV gama
ray.
before
To obtain
and after A sunssary
neutron of tho
and radioactivation Table for
23.
maximum sensitivity,
Np should
be purified
irradiation.
sensitivity
methods
In summary,
the
alpha
and sel,?ctivil:y
of radiometric
for determini~g Np is presented in counting
is the ~!;t convenient method
237Np, and gamma spectrometric methods are preferred for 238Np
and 239Np. Because of the contirr~ingadvancements in nuclear radiation accuracy
detection of the
systems,
radiometric
the
sensitivity, precision, and
methods
- 110 -
discussed
above could be
O.ostoo.lmg
s m 10-b
O.u
1O-B .. m -. so o.z m1 10-~ .. 50 -. M 10 .. 5m Jo-” .. Icm .. ,@l M sm Ir’ ... so .. .. co 1] (0.1
O.oa , ,1 O.OJ
I a
0.1 to 0.s ~
0.01 to 0.1 q
0.1
M
0.s
Iq
10-m-i
[0.1
10”’ tm
10 to so
,.,s 111
Yoto
1,1”
0.0s
It’ lo tow
G.1 I 1
.. 1 1
101
u
0.
uJtozQ
In
10
0.
CO 1]
...
10”” W1
Stoa
.. Iw . . Iw
10-’ 10
10-1 KI
(>1)
Ic’
(>1]
●o* ●18’
(>IM) . .
0.1
. .
0.1
. .
I
[10s) 1 1
T-w-” -
~sa
tm #
●Iw
‘‘*I
F?
-
111 -
. .
100
Ill
5t000
●
improved with available advanced instrumentatim. Preparation.
Scurce
❑ethod
for preparing
disadvantage
for
sample
alpha
pulse
(S0 pg/cm2) evaporated
and bums
in self
evaporated
to dryness
to dull
collodion
rather
than
solution,
thickness
of the alpha
the NIP solution
a drop resu,~ting
sample
cooled,
on heating
is transferred
steel
disk,
and coated
with
to
and slowly
The direct
spattering.
is
in a more
polymerizes
stainless
e.g.
to prevent
a thin
munt
is
layer
of
and the Np is counted.
ElectrodePosition
has been widely
sample
mounts for precise
useful
when samples
alpha
contain
used to prepare The procedure
counting.
a mixture
of
high-quality
alpha
emitters
is extremely that
need
Electrodepositionresults in excellent sample
to be resolved.
mounts fmm organic
solutions
amounts
of residue
large
a-nts
of dissolved
Np and other
that
very
slowly
solutions
that
or leave contain
solids.
actinides
●nd under
evaporate
and fmm ●queous
large
electrolytes
absorption
The diluted
plate,
red heat,
solution,
is the
The surfactant
up when ignited. counting
The
such as tetraettlyleneglycol
deposit.zc’’z~’
a suitable
counting.
analysis
is added to the aqueous from a film
homogeneous
for
height
If a surfactant
particles.
evaporation ig the simplest
aliquots
which results
of the deposit,
flamed
Direct
can be deposited
sewral
conditions.
-
112 -
from
a vmriety
Gravessgg
of
described
a semiquantitativemethod
for
depositing
237Np from Li onto Pt.
Ko27~)reported a method for quantitativedeposition of Np from O.ZM HC1OQ - 0.15M NH4COOH, and Mitche11271 used NH+C1 - HCl to obtain a yield ofâ&#x20AC;&#x2122;94%. Some systems used by other workers272-274 are formic acid-ammoniumformate, ammonium coalate, ammonium acetate, ethanol,,isopropanol,and Nli4Clwitt uranium carrier. Donnan and Dukes275 developed one of the!fastest procedures for quantitativedepositions by combining Mj,l/chellâ&#x20AC;&#x2122;s methoclwith uranium carrier addition. 23aU is added as
ii
carrier in three
increments to the NH%Cl electrolyte to ensurf!quantitative yield; only 20 minutes deposition time is required. An average recovery of 99.8% with a relative standard deviation {IftO.2% (n = 10) was obtaind with Pu. Similar results were obtained with Np. Resolution of 20 keV is achieved consistentlywith electrodepcsited mounts and a silicon surface-barrierdetector. Parker and Colonomos276reviewed electrodepos;Ltion procedures and described two new methods. One is a co-depositionmethod for alpha-spectrometry,and the other for preparation of carrier-free method with layers as fission detectors. In the co-depc,sition uranium carrier,,237NP was deposited quantil.ativelyin 10 min at 170(0V with stainless steel as the cathode. In other recent work, Np was deposited quantitativelyfrom ammonium oxalate
or ambonium acetate solutifm or mixed ammonium
- 113 -
oxalate-ammoniumchloride electrolyte.z’’-zgo Alcohol is an excellent plating medium for aqueous and orgalic samples. Methods have been reported with
for
and oxalic
The effect
of variables
other
actinide Other
with
methods
excellent
several
acid
designed
include
electrolytic
special cell
and special
electrostatic
by other
but yield
take
a longer including
and electro-
time than
high
a needle
have
a specially
for electrodeposition, with
sources
and (!lectrospraying
equipment
capillary
on Np and
authors.:1e5’2aG
vacuum sublimation
These ❑ethods
hydrochloric,
by Palei.20+ deposition
Both electrodeposition
and require
equipment,
has been reported
which have a lower efficiency
resolution
saturated
from sulfuric,
Deposition
has been reported
disadvantages.
evaporation
md alcohol
on the quantitative
elements
spraying.28b-2g1
voltage
electrode
for
spraying.zGG
SPECTROPHOTWHRY Although
bands,
different
oxidation
analysis
spectrophotometric
rmdiometric
procedures
a glove actinides single
from
box is tedious. can be applied oxidation
the nlar
state,
extinction
states
of
NF have
has had liuited
are mme sensitive.
ment is required for the
●
isopropanol,
ammonium chloride.201-2B3
perchloric,
B.
ethanol,
spectmphotometer, Generally,
alpha
anu opermtion
procedures
and the concentration and the
absorption
use because
Further,
to the determination.
coefficient
sharp
containwithin
used for other Np i:~ adjusted
to
is calculated absorption
of the
- 114 -
..-.
solution at the proper wavelength. When more than one oxidation state is present, appropriateequations ma:~be formulated for the concentrationof each component.=g= Abaoz@ion
Important
Bade.
absorption bands and molar
extinction coefficientsof the different oxidation states are listed in Table 24. Most of the
sharp
bands
can be used for
qualitative or quantitativework even though they only obey Beer’s
Law over
a limited concentrationrange. The best band to
use for analysis of Np(III) is at 786 mp kecause this band Beer’s
Law.
The strongest bands for Np(I\’)(960 mp,
do not obey Beer’s calibration
Law, but they
and constant
slit
can be used with
width.
obeys
723 mp)
appropriate
The strongest
band for
Np(V) (at 980 mu in lM HNOS) does obey Be{:r~s Law;2qo a highresolution should
mmochromator
be used.
(e.g.,
Cauchatier’
method for determining
hydrazine
evaporation
Np in irradiated
acid
is necessary. The most useful Colvin nitrate
developed
hexavmlent
●djusted
state
with
to 1 to 2U.
❑ixture
solution.
fuels
state
this
after
Correction
for
Np is oxidized
sodiID
bichromate,
and thm
is measured
1.23 urn; in
to the
the acidity at
by
Pu(VI)
band for measurements
method,
- 115 -
by measuring
obtained
In this
The ●bsorbance
a
is produced
band for Np(VI) :1s at
a method using
solution.*9’
have developed
nuclear
The pentavalent
to a Np(V]-Np(VI)
of the nitric
monochromator)
and coworker:;2go
the Np(V) band in lM HN03. adding
a double-grating
1.23 urn
is
TABLE24 IMPORTANTABSORPTIONPEAKSOF NEPlUNIltN2g’-2s’
Np(II1)
Absorption 8and [w) 55P 60~#d
~la,d ,86b,d
Np(IV)
84E+ 991b 1363b 50CF ~wa,d 590.5=~d WOCF cd‘ ~71s 7z3b
74f’d
m(v)
800C 825ad‘ 961# 975= 428a ~l,b,d ~17cJa’
N’Pwl)
Np(VII)
Coefficient 44.5 25.8 30.5 44 (50to 60°C) %25 W27 -39 %15 22.9 16.1 % 7.5 ~ 3.7 127 43.0 %2] 24.5 162 %32 11,1 22 --18 395 %]80 6.4 6,8 45 %43 1370?40 382 *1O
MolaI” Extinction .—
98& W39CF 476a 55P 1223bJd 1230c’d 412* 618e
a. lM lCIOq. ~1.~ ~lo,. c. IM HNOJ. d. Obeys8eer*sLaw. e. KOH Solution.
- 116 -
against a reference HN03 solution that i:;the same HN33 concentration as the sample. The method has a relativu ?0.5% at
3 g/k.
when present water
A number of ions,
in amounts
solutions
ten times
of neptunium
bands were found in the
including that
salts
region
standard
deviation
of
Pu, do not interfere
o:: the Np.
A study
in wh:.ch numerous
on heavy
well-defined
1.2 to 1,11 Um is reported
by
Waggener.sOO color
Spectrophotometric
cmph?xe8.
Furthermore,
sensitivity. coefficients
the position
are affected
These disadvantages
complexes
that
A â?&#x2018;ethod
6-disulfonic
with
arsenazo
acid-2,
III
7-bis(azo-1)
The intensity
reported.301-303
III
forms instantaneously,
and its
concentration
range
extinction [1,
coefficients
-2-arsenic
are
acid]
is
complex The color
al: 665 mu.
intensity
4 to 6M HN03.
when color
8-dihydrcxynapthalene-3,
benzenn
is measured
Np concen-
overcome
of the s~:able green
of Np(IV] snd arsenazo
the
and by the
are pafi.ially
have very high mlar
for Np lack
of the band extinction
by some anions
tration.
used.
methods
is constant
over
The molar extinction
coefficient at 665 mp is %105. Chudinov and Yakovlev separated and Th(IV),
U{IV), Pu(IV),
NpC)2+by extraction carbon
tetrachloride.
and arsenazo 0.04 vg/ml,
III
with
which fozm colored
complexes,
di-2-ethylhexylphosphoric
After is added.
and the relative
extraction, The lower accuracy
- 117 -
acid
Np is reduced lirlit
from (HDEHP) in to Np[IV],
of detection
is between
1 and 7t,
is
Bryan and Waterbury302 separated Np from U cnd Pu by extraction with tri(iso-octyl)amine(TIOA) before d~!terminingthe arsenazo 111 complex. They found that of 4S ~!lementsteste:i, only Pd, Th, U, Pu, and Zr interfered, The :r{!lative standard deviation was between 7.2 and 1.1$ in 200-mg :;amplesof 8.S to 330 ppm of Np.
(Procedure 20, p192.)
Novikolr et aZ. have
studjed the color complex of Np(IV) with Arse]lazoM.30” At 664 mu the molar extinction coefficient is 1.18 x 10s in 7M HCl and 9.5 x 10” in O.SM HC1. Thorln was used by several.workers to analyze ?Jp.30S’30G The absorbance is measured at 540 mu against a reference solution not containing Np. The molar extinction coefficientmeasured with a Beckman DIJspectrophotometeri.s~~14,500. The precision of the method at the 95% confidence limits is t2.1% fo:r0.63 Ug of ?Jp/ml . Chudinov and Yakovlev used extraction to separate Np from U
and
Fu interferences. The thorin method has also been automated307
with the Technican AutoAnalyzer, and the pr~’cisionhas been, improved. Np reacts in weakly acidic solution (pHv2) with xylencl orange to form a colored complex with an absorbance maximum at S50 mv and molar extinction coefficient of 5,S x 10*.3*8 X,ylenol orange is three times more sens~tive than thcrin but only clne-half as sensitive as arsenazo 111 as a reagent fcj~Np(IV), The greatest
- 118 -
advantage
of xylenol
orange
is that uranyl ions do not interfere.
Fe(III), Zr, Th, and Bi interfere. Np(IV) forms a color complex with quercetin that is stable in the pH range 3 to 7 and obeys Beeris Law ove:ra concentration range 0.4 to 4.0 ug/ml. z2,3
x 10b at 425 mu.
The molar
extinction
coefficient
is
This method requires an extensive purification
to remove cations and traces of organic i:npuritie~,30g The color complex of Np(V) and arsen~zo narrow
pH range
and was studied
by Chudinov
111 exists
over a
md Yakovlev.
310
A
method with the green-coloredcomplex of llp(V)and chlorophosphonazo 111 was also developed by these workers.~:] Chemical separation or masking agents are required for a nurbcrrof elements. Chudinov has studied spectrophotometricallythe interactionof 12 organic dyes of different types with Np02+.312 He concluded promising rt?sorcinol
reagents
for pentavalent
(PAR), arsenazo
neptunium
CONTROLLED POTENTIAL
Determination
the most
l-(2-pyridylazo)
111, and chlorophosphonazo
the molar extinction coefficient is M.3
c.
are
that
111.
With PAR,
x 10â&#x20AC;? at 510 mu.
COULOMETRY
of Neptunium
ConcentratLo~.
Alpha counting is
generally superior to coulometry for determining less than a few micrograms of Np; however, controlled potential coulometry is an accurate and precise method for determining;Np above the 10-Dg level.313 The electrolysiscell contains n platinum electrode at which the Np(V/VI) couple is titrated in OSM HzSOd. First,
- 119 -
the Np is oxidized to Np(VI) with Ce(IV), the Np(k’1] and Ce{IV) are electrolyticallyreduced to Np(V) and Ce(IIl”],
and then Np(V)
is coulometri(cally oxidized to Np(VI). T’leintegrated current, in the last step is ~lsedtc calculate the concentrationof Np. The standard deviation ranged from 6’%for 7 Bg to 0.05% for about 1 mg of Np.
AS little as 2 ug was detectl>d. Elements which
significantlyinterfere are Au, Pt$ Hg, “rl,and Cl ; Pu and Pd cause only slight interference. Stromatt’s method was used successfullywith a gold electrode insteallof a platinum electrode to eliminate the Pt/Pt(OH)2 reaction repw:ted by Fulda.9i~ Fulda obtained a precision of tO.6% for [5mg of Np.
In another
applicationof Stromatt’s method, the prot:isionwas O.1% (n = 8) for 9 mg of Np.
Also, 3uckingham31s demo]lstrateda coefficient
of variation for the coulometricmethod o~:*0.8% for neptunium o~ide and ?1.11$(n = 11) for neptunium nil:ratesolutions. Delvin and Duncan316 used the same method in the presence of nitrate with H2S04 electrolyte. Plock an(lPolkinghorne]17used coulometry to analyze solutions of dissoltredalloys for both U and 318 has reported a i’Jp without prior chemical separation. Plropst coulomtericmethod for Np using a conducltlngglass electrode in a thin-layer electrochemicalcell. Organic contaminants interfered and were removed
by bisulfate
fusion
- 120 -
befo:.e
coulometry.
Determination the
(IV),
(V),
The analysis
of Ozidat ion States.
This method
applies
to
and (VI) states and was reportej by strOmatt.’l’
depends
on the
fact
that
Np(IV) i;
not clxidized,
nor
is Np(V) reduced at a significantrate at a pl~tinum electrode in lM H2SO~ electrolyte. at the
controlled
The procedure potential
electrode
is:
(1)
~ potential
to reduc:
is applied
Np(V1) to Np(V);
(2) Np(V) is electrolyticallyoxidized to Np(V[); (3) Ce(IV) is added to oxidize Np(IV) to Np(VI); (4) excess :e(IV) an?
and Np(VI)
electrolyticallyreduced to Ce(III) and Np(V); ard [S) Np(V)
is electrolyticallyoxidized to Np(VI). Np[VI) is determined in the first step. The difference between the integrated currents for the first and second titrations corresponds to Np(V], and the
difference
between
the
integrated
currents
for
Step
S and
Step 2 corresponds to Np(IV). L&termination
for the Np(V)/(VI)
of &idation-l?e&ction
Pot.e~tia2.
The potential
couple was ❑easured in sulf~ric, perchloric, and
nitric acids with a platinum electrode.g2 The ~tential in HC1 was not obtained because of reduction of Np(VI) by chloride. The inability of the method to measure irreversiblecouples, such as Nap/, the Np(III)/(IV) D.
is a serious
limitation.
couple
was obtained
current
polarography
with
The potential a mercury
for
electrode.
POLAROGRAPHY Alternating
with
polarographshas been applied to detemine
- 121 -
square-wave
small
or pulse
concentrations
of Np+) Slec with
and othurs J*’ have reported
square-wave
liminary
polamgraphy
separation
extracted
froa
tions with
nitric
acid acid
residue
hydrochloride
and uet
(to
reduce
the wlw
is to
~
0.S
@i S.S
transferred
to a polarographic
The
is
Nppeak
electrodo
recorded
at
asterixl],
to
cell
on the square-wave
is evapwated
2 IUI and
several
of the dilution
\pargedl
-0.8V
a~ainst
the
nitrogen. IS4WCUX’Y
the cell, and the !Wpconcentration in the ori,ginal
Interference by adding
from the EUrA
The patential
oxidation
prepared
increase
in EDTA is
in peak height.
of chloride
ions
is decreased
to shift the half-wave potential.of the Np peak. for
the reduction
700 mV more negative therefore,
from the
pl
Then an accurately
added
is calculated
Np soiutin
with
of
are
aliqwt
solution
to
drops
measured to
per-
;! mg of W hydmxyi-
6.$ with
polarograph.
of a standard
final
0.S id of IM EDTAis added;
Exactly
about
the
the solution
Then,
to S ●l.
and diluted
with mixrd nitric
organic
and
IS1. to
sewer41 evapora-
in i ml of (IKI.
●dded,
pre-
!tp is Ihack-
After
ashing
oxidize
solution is adjusted
amsonia
IOM HMI1.
method
%@in Pu after
Pu by 77X extraction.
is taken
amine
the
to determine
the ITA into
and perchloric chlorate
from
an analytical
than
for
the peak is shifted
of chloride ions
of the the
reduction
well
and is well
EDTAcomplex
defined.
of
is about
neptunium
away from the anodic T~e authors
ions; oxidation
report
precision of f2$ and $10% for concentrationrarlgesof 500 and 25 ppm, respectively.
-
122 -
Caucheeler
ut al,**O
the Xp(lV)-Xp(lll)
couplo
irradiated
fuels
nuclear
reported for
a method whi~ch makes use of Np :iIt solutions
determining
●nd 2“Xp
!ip is reduced
targets.
wlactmiyticaliy to Np(lV), and the polarograa standard
‘repeated
.
The method
content
>20 mg/t
was used
coatainigq
chemistry
of
U,
with
$tudied
studid
E.
methods
to study
Np(II1)
the
!di,
Cr,
were used at
nature
with
is
a NIp
and fission
to coq~re
the
Jenkins
umd
aZ.)2* and
and Np(IV).’a’
and perchlorate
stability
Np(IIl)
a
of EMA,
and ([V)
wem
media by Hiwken
and
eiectroch,aistry
of the
*
Np was included ●ctinides
Fa,
?/p, and Pu by Kraus,
in chloride
Kritchevsky,8*
U,
utd the procethm
solutions
analyze
An
of~2%.
and other
manual, po ●mgraph complexes
to
Pu,
[products,with 8 precision FWmography
is taksm.
Sp is added to the cell,
of
iali~wt
of
in a review
by Milner.’2*
of
The sulfate
polarographically
Np(XV) were
of
complexai
by hsikm.a’
TITRATIW Potenthmetfia.
by redox
titration.
and iron(II)
10- to 100-mg quantities $2S
CC(IV) iS used to titrste
perchlorate
was used to titrate
methods
can be used successively
if WI
is present
and chloride
cf
(to give
ion is absent
the (it
on the required
detomined
?/p(v) to N@(VI),
llp(VI)
same ~lliquot
to W(V)* fie of sasple
ceri~:oxidation
would be oxidi:~ed
123 -
Np were
potential]
to chlorine).
.
..--!...
.,
.!’-...
.. . .
Stoppered
.. . .
. . . . .
.
weight
burets
fezmus
for
deviations
a single
titers and 0.S9S
Colnpbttiu
Tftzu’tion.
of Np(IV) with
changas
from bright
The error
Zrh+,
rose
in 0.01
Pu’+,
of alkali,
Cdz”,
CO*+, Cr’+,
to light
Mn2+, Ni2+,
have been obtained
quantitatively
SOO”C with
an ●ccuracy
at equal i:~
The color
molar
1 to 2%.
concentrations. Np(IV)
earth
is
reductant.
Fe3+,
Reasonably
interfere.
and U022+
elements,
large
Zn2+,
not interfere.32G
do
hJ~ been little
analytical
, and so c~r the only useful
in molten
methods.
results
31p(IV] was
LiC1-KCl eutectic
at 400 to
SPECTROMETRY
at 4~54.5,
emission
4098.8,
3999.5,
for quantitative
spectrochemical
method,
carrier
acid
a solution
and the
ofNp
rare
salts
are more useful
spectral
with
of t4S.327
Np has a line-rich
of imprity
for
orsngw as in.iicator.
from electmanalytical
dete-ined
lineS
4 q
There
done in molten
EMISS1(M
is titrated
yell-
alkaline-earth,
(%Wopotentirntric.
F.
xylenol
and ●scorbic
-Unts
chemistry
were 0.15#
to 0.05MHC1 with hydroxyl,smine
Th’+,
Relative
titers.
Np(IV)
1 to
and a
the end points.
EDTA is stoichl~tric
fordetemining
produced
reagents,
determination
for eerie
of EDTAat pH 1.3 to 2.0 with
reactim
adding
~ystem was used to detect
plmtinu-cal~l standmd
were used for
elements. lines
with the more-sensitive
and 3829 ;1.32S’329 determination
which is generally To prevent
of Np, a chemical
distillation
spectra
method with
Other
of Np than
used only
interferenceby the
for
methods the
analyses
numerous
sepamtion is usually made, galliw
- 124 -
sesquioxide
is used.
or
the
A quantitative
is reported
method
for determinaticw
of impurities
by Wheat 232 (Procedure23, page 200).
a modification
of one reported
by Ko for
Pui.s30
in Np
The method is The neptunium
oxide is dissolved in HNOy, reduced to the tetravalent state with hydrazine and sulfamic acid, and then sorbed on anion exchange resin. Two cycles of anion exchange are
IJWd
Np.
to
The second
hydrazine,,
effluent
is evaporated
The residue
is made water
to dr~ess,
evaporated
and dissolved
to dryness soluble
with
to separate decompose
aqua
regia,
in 6M HC1 containing Co as
the internal standard for the spectrographicanaiy:$is. The coefficient of variation for a single determinationof a numbe:rof common metal ion impurities ranges from 9 to 24%. For a 50-mg sample, the minimum concentrationof impuritiesthat cam be analyzed is 0.5 to ;LOppm, G.
GRAVIMETRIC METHODS
Precipitationof Np for gravimetric determination is not a useful method. If other ions which form insoluble salts are present,
these
must be separated first. When the solution is
relatively free from other ions, alpha counting or some other method
is
usually
more rapid and offers less health hazard. A
number of Np compounds have low solubilities in aqueous sc~lution; however, indefinite stoichiometryor necessity for calcination to
the oxide limits the usefulness of direct gravimetric
determination. Often the small quantity orâ&#x20AC;&#x2122;low concentrationof neptunium precludes the use of gravimeery. - 125 -
ffycbwidr. acid
Np(IV)
solution
hydrous
The broun-green
to filter
volubility it
hydroxide
solution.
hydroxida
solid
that
hydrated
precipitated
excess
NH*OHfrom minaral
is precipitated
3%.
!Up(V] ‘%ydruxid.”
dark
brown
scid
solution.)’
f;rom mineral
excess
in rewgents which complex acid.
●s
is
NpFh by adding
is
in a sodiuw nitrate-sodiuu
Np(VI)
Np(IV)
or
fores
in ●cids.
redissalvd
is somewha~ mora soluble
Flwrid%a.
boric
gelatinous
is ●asily
but
(NH~)2NpaOt~HaOwith
readily
from minaral
in lM NaNOl - lM NaOH is ~0.1 rig/L.
i:~ green;
as green
precipitated
by Na, K, or MibOH as the hydrated
oxide.
difficult
is cqletoly
iii:.
fluoridl~
ac:~d solution
The compound dissolves ion,
such as AIJ+ or
Wlwn K or NH~F in usad as tlh(l precipitant, tha green
double salt KBIp2F3or NHklUpFs is produced. Pertmide,~. large
excess
Purple
Np(lV) peroxide
of H202 is added to a strongly
Nip(IV),, NP(V), or Np(V1), Np to the tetravalent mineral i~ion
iS precipitated
because
Reduction
state.
Np(lV) peroxide
acid.
peroxide
always
when a
acidic solution of rapidly
reduces
is much slower irtcorporates
in dilute
SOW! of the
into the crystal and may have diffc’rentcrystalline forms
depending on the acid concentrationof the supematant, separated peroxide.
from many cations
precipitation
of neptunium
~t Green Np(lV) oxalate
Llxalatefl. from dilute
by precipitnl;ion
Np iS
acid
solution
with
is not attained
oxalic
he:ukhydrate a~cid.
is prl~cipitated
Because
for Np(V) Jr Np(\’I]P
- 126 -
quantitative
a reducing
●gent,
such as ascorbic
to Np(Iv]. under
acid,
granular,
A
easily-filtered
have ●lso been precipitated
acid
by adding
Cdwnata produced
and N@12HC20~
excess
icxiate
is precipitated
potassium
by adding
potassium
bicarbonate
light
is heated
tan double Aaotute.
solution
in bicarbonate.
3 to 4 hours
Sodium neptunium lS pink
light.
to produce
the
dioxytriacetate,
by transmitted
Np is oxidized
90*C to Npo22+. an equal
acid
salt.-’
NaNp02(C2H~02)~, reflected
at 90’C for
KNp02C03, is
to a d:llute
of Np(V], until the resulting solution is O.IM The solution
dilute
from
iodate.’s
The double carbonate of Np(V),
.
is produced
from P@(IV) and Np(V) solution.
Light tan Np(IV)
Ioti.
precipitate
(Nli~)4Np(C20~)k
conditions.”o
controlled
mineral
is usul to ensure complete reduction
in dilute
Sodium neptunylacetate
light acid
and pale
green
with
KBrOs at
is precipitated
by
by adding
of 4M NaNOS - 4M NaCzHS02 solution.38
voltme
Np(IV) di(monohydrogenphosphate)hydrate
%08DhUte .
[Np(Hpo~)z‘~zo] , a pale-green gel, is precipitated by adding phosphoric acid to a dilute acid solution of Np(IV).35 ii.
SPOT TESTS Spot tests
were obtained
for determining for
36 organic
oxidation and inorganic
states
of Np and Pu
reagents
coimnonly used
in paper chromatography.331 The tests we::emade on Whatman No. 1
- 127 -
paper for
which was treated 12 hours
treated
to
with
remove
sensitive
2M HC1 in descending
traces
of Fe, Mg, and C=,
two successive
twice-distilled and the high
with
uater.
Because
sensitivity
spot
tests
1 ug of actinide
24-hour
of hazamis
of radioactive with
light
alpha
measurement,
very
limit
acidic
was added and evaporated.
A standafi
and basic
scale
emitters
of less
than
were made in white
First the acidic media was allowed
reagent.
WBS
with
of these
Observations
for both
The paper
â&#x20AC;&#x153;sy migration
an identification
were selected.
and ultraviolet
washings
chromatography
mclia
to
dry;
with then
of colors
each ~nia
was used
for comparison. In most cases, a color reaction was obtained with less than 1 ug of actinide, but the color was the s-
for
all oxidation states of both Np and Pu. Diphenylcarbazide Np(V);
a color
gives
the
Pu(VI]
however,
solution,
gives
sodium alizarinsulfonate
reaction with Np(VI] but not
same color
~e~tian.
or arsenazo
In acid
give
a color
with
Pu(IV) and Pu(VI), but no color with Np(V) and Np(VI). Four of the reagents,
chromazural-S,
and pyrocatechol, with
all
only with
oxidation
give
arsenazo,
fluorescent
states
spots
4,2-ppidyl under
of Pu and Np; kojic
-azo-resorcinol, ultraviolet
acid
light
fluoresces
Pu(III).
The oxidation states of Np and Pu were characterized color reactions
on chromatograms
and electrclpherograms.
- 128 -
from 2s&
The tetravalent arsenazo-1,
states and thorin-I;
the hexavalent I.
give
characteristic
however,
colors
with
diphenylcarbaxide
alizarin,
was used for
state.
MASS SPECTRCB4ETRY Subnanogram
quantities
of 237Np were determined with a mass
spectrometerby Landrum, et al.sgz The instrumentwas a doublefocusing, 60-degree source
sector
chamber contained
sample was volatilized)
type,
with
a tantalum
a 12-inch
filament
and a rhenium
species were ionized]. After
radius.
The
(from which the
filament
mass analysjs,
(on which gaseous the
ionized Np atoms
were collected in a Faraday cup. The method uses isotopic dilution with ‘35Np or preferably 236~p. rapid
than
This method is much more
neutron activation, and the sensitivity is at least ten
times grecrer. The standard deviation fo”:0.1 to 0.S nanogram of Np was 1 to 2%. applied
to determine
Spark
source
measurements
Isotope dilution with *’gNp has also
been
237Np.333
mass spectrometry
of many elements
is ussful
including
fc~r less
Np; however,
quantitative it
is
most
often used for determining cationic impurities ~LnNp and other actinides.334 J.
X-RAY FLUORESCENCE SPECTROMETRY The ease
of production and simplicityof the X-ray spectra
produced for elements
of high
atomic
- 129 -
number allow mixtures
of
actinides
to be analyzed
considerable s~les
by X-ray fluorescenc,~
precision
and accuracy.
can be analyzed
Mixtures 1:1:1;
were comparable
Pu in any combination
ratios
present
X-ray emission 96 are
given
fluorescence solutions
low results at lower lines
by Kofocxi.s35
1 Dg Np was 5%, ~d required
at ratios However,
atomic
at
the
L series
nwnbers â&#x20AC;&#x2122;32 through X-ray
amounts of Np in pme
containing
the analysis,
for
The principal
with
microgram
30 to 40 minutes.
Pu.
The sensitivity
was
standard
error
in determining
including
s~ple
preparation,
The Kal and Kaz X-ray energies by Nelson,
for
et al.337
NEUTRONACTIVATION Neutron
of
U, Np, and
accuracy.
Novikov et CZZ.3â&#x20AC;&#x2122;6 used
Np, PUB and Am were measured
K.
affecting
The relative
0.2 to 0.3 pg ofNp.
counting.
of 5 to 7% were ojtained
of elements
or in solutions
as high as
were ani~lyzed
concentration.
to determine
technique.
at ra:ios
to standard
seriously
with
.~olid er liquid
stsnd,mi
of two elements
1:8 without
as
of 1:10,
element
intenal
of U, Np, and I% were analyzed results
as high
by the
Either
spectrometry
237NP.332
sample avemge
activation The
was used to determin~!
subnanogram
unknown sample was i~adiated
of known Np content time-integrated
and comparable
neutron
flux.
- 130 -
with
weight
After
another
in the
irradiation,
quantities
same
Np
the 23BNp was determined
by gamma spec:rometry.
radiochemical
methods
with
separation
mass quantities
of
were ?Ised.
Conventional Isotopic
dilution
237Np ser~ed t,)determine chemical
recovery.
L.
OTHER METHODS
Gamma counting 239Np, the decay product of 2k3Am, has been used to determine 2â&#x20AC;&#x153;3Am in solutions containing large amounts of Cm. The ratio of the equilibrium amount of â&#x20AC;&#x2DC;3gNp to the amount of 2b3Am was determined by separating (by TTA extraction) and analyzing (gamma counting) 239Np from jample~ in whi,:h~hq.kmand 239Np were known to be in secular equilibrium. The method was compared to determining 243AM by the isotope dilution-mass spectrometric method. The precision of the msthod was 7% at.the 95% confi~ence limits (n = 16) for sample ali~uots that contained 0.1 to 5 Llgof 243AM.33B A similar approach #as reported hy Lebedev et aZ.202 2]3Pa, the daughter of 2;7Np decay, has more-abundant gamma rays, which are easier to measure than 237Np. Cofield33g used this as a basis for determining 237Np-233Pa in human lungs by in uivo gamma spectrometrywith a large NaI SC:ntillation detector in a low-backgroundcounting chamber. The neutron capture cross section of 23BU
was
measured by
analysis of 239Np produced [23@U(n,y)23gll~-23gNp]. The procedure uses isotope dilution with 237Np to dttermine chemical yield, ITA extraction for separationof Np ard U, electrodepositionfor
- 131 -
Np source
preparation, and gamma counting3bofa? analyses.
Characteristic isomer st,iftranges have bem fcr
measured
several valence states of Np using l&sbaue? resonance
of the
59.54-keV
gamma ray
of
237t-ip.
They
exteld from about
-6.9 cm/sec to +5 cm/sec for the individualoxijation states of +7 to +3 and are clearly defined.3*1’3”2 The isomer shift characteristicof each oxidation state is useful for !,tudyof bondi~g
in Np compounds. Dunlop and Kalvius have also made
significant contributions.3kla
Ix.
RADIOACTIVE
SAFETY CONSIDERATIONS
TfieSipisotopes emit high-energy alpha pa]hticles,mediumencrgy beta particles, and low-energy gamma rays.
The tendency
of Np tu concentrate in the bones with a biolo~;icalhalf-life of 7.3 x 104 years makes ingestion the primary hazard to personnel. Studies of the distributionof 239Np in animal tissue showed 60 to SO% of the ?Jpwas Csposited in the bone-.131 Studies have ii[so
been ~de
of
the
inhalation,
pulmonary
absorption, gastro-
intestinalabsorption, and short-term retention of
in rats.3”3
2:17Np
Because 237Np (T$ = 2.14 x 106Y) is the only isotope of Np which is available in weighable amounts, it presents the hazard.
The riidiatim
hazard
activity of 237!Jp and the 25 lists body burdens ‘“SF
is small
low energy
due to the of its
only
serious
low specific
gamma radiation.
Table
and maximum permissible concentrationsof
and 23’Sp for continuotisoccupational exposure.’”b In
- 132 -
handling Iarge quantities of 237Np, standa~.dgloved-boxe:j maintained at a negative ~ir pressure with respect to the laboratory airq~s should be considered for containment. Criticality is no problem for 237Np belcausethe bare critical mass for a sphere of density 20.4S g/m3 is 68.6 kg.’kG
TABLE 25 HEALTH HAZARD OATA FOR NEPTUNIUM
Isotope 2s’Np
(s01.:)
[SOTOPE:S3””
Bone
0.06
Maximum Permissible Concentration for 40-hr Week (pCi/cc) ~~ —— .— Air 9 x 10-5 4 x 10-12
Kidney
0.1
2 x 10-”
0.5
4 x 10-4
:’ x 10-*2 ;? x 10-11
0.s
6 X 10-*
2 X 10-]1
9 x 10-4
;!
Organ
Total
Body
Liver
Max Permissible Body Burden (uC:~L,
GI(LLI]
1o-1o
tinsel.:t Lung z ~~~
(sol .:)
G](LLI) GI (LLI)
9 x 10-b
;! x 10-’
4 x 10-3
8 x 10-7
Bane
30
100
41x 10-6
Kidney
40
200
70
300
7 x 10-6 ]*-S
100
Soo
2! x 10-5
4 x 10”3
7 x 10-7
Total Liver (insol,j
x 10-7
Body
GI(LLI) Lung
2 x 10-6
- 133 -
x. A.
COLLECTION OF PROCWLJRE!i
INTRODUCTION
The procedures Procedures
o
exchange, these ❑ethods
gaxna
are divided
for extraction, and carrier
n.athods
with
utilize
three
highly
chromatography,
or possibly
ion
or :wme combination
radioactive
counting
method of determination
cal;egories:
extraction
precipitation
alpha
spectroscopy,
into
(alpha
swnples. pulse
isotopic
is not detailed
of
Most of these
height
analysis),
dilution.
The
for all. procedures.
e
Procedures
o
Miscellaneous procedures for quantitativedetermination,
used for environmentaland biological samples.
including absorption spectrometryof color complexes, coulometry, and gamma spectrometry. B.
1.ISTING OF CONTENTS
Procedure
1
Author Moore*”e
Title cr —. —.Method Separation
c~ i4p b:yTTA
Extraction ‘> ,.
DorsettlS*
Smilh3”7
138
Separation (IfNp by TTA Extraction
.3
*
141.
Determinati(mof 239NP in Samples Containing U, Pu and Fission Products
4
Landrum34B
Detenninatilmof Np
s
Slee et C7t.’zo
Determinati4mof Small Amounts of :* in F’uMetal
-134-
14s 150
1s5
Procedure ——. 6
or Method .Title . ——
Author Schneider)qb
Determination0!?Np in Samples Contain:~ng Fission Product!;,u and Other Actjnides
7
Maeck et aL.185
1s8
Determinationof Np in Samples of U and Fission Products
8
Wehner et UZ.252
161
Extraction Chromatographic Separation of 2’]9?4p from Fission and Act:Lvation Products in the
[determi-
nation of Micro and Submicrogram @I;Nitit!Lt3S of U 9
163
Separation of U, Np, Pu,,
Eschrich2”9
and Am by Reversed Phase Partiticm Chromatography
.10
R,oberts2*”
An Analytical Method far 237Np Usjng Anion ExchaLnge
11
Nelson et 220223
Jackson et al,’kg
Zagrai et aZ.23g
Sill123,
173
Separatism of Np and Pu by
1s
171
Separatism of Np and Pu by Anion Exchange
14
~69
Holloway et aZ.*2° !3eparaticnof Zr, Np, amd Nb Using Ar,ionExchange
13
167
Separati.cnof U, Np, and Pu (JsingAnion Exchange!
12
16S
124,12S
CaticnlExchange
17s
Separatism and Radiochernical Determin$ltion of U and ‘Transurallium Elements Using Bti~bium Sulfate 13s
“
176
Procedure
Title or Method — —.
Author
Page
T@? II 16
Taylor’so
17
Perkins]ss
Radiochemical
Determination
of 237Np in
Envinmmertal
Samples
Radiochemjcal
Procedure
the Separation
of Trace
179 for
21-Np from
ADounts
of
Reactor
Effluent
Detemina:ion
8utler35~
18
The Low-Level
Uater of’ Np in
Urine ~pe 19
186
III Dete2minacion
Granadelsz
by G~
20
of 2B7Np
Ray Spectrometry
OF 193
* Microvolmetric
SmimovAverin
et
a2.32G
metric
Coeplexo-
Mdwd
for
Np with
EDTA 22
189
Spectrophotometric
Bryan et aL.302
Deteminution
21
184
Novikov et al. B53
197
Photometric
Determination
of Np as the Peroxide Complex 23
Separatim
Uheat 2‘ 2
199 of Np for
Spectrographic
Analysis
of Impurities 24
Ermoloev
et aZ.30s
Photometric
201 Determination
of Np as the X~lenol Orange Co~lex
- 136 -
204
Procedure 2s
.Title —— or Method
Author Stromatt31’
Analysis for Np by Controlled Potential] Coulcmetry
- 137 -
206
Procedure
1.
Separation of Np by HA F. L. Fbore*”o
of Mt?tlwd
i?utl~~
Np is separated elements,
from fission
and nonradioactive
thenoyltrifluoroacetone suitably
prepared
counting
of 23qNp.
Reagent8
for either
(C.F.
After
alpha
U, Pu, transplutonium
by extraction
into
separal:ion,
counting
an aliquot
of 237Np or gamma
lM
●
HN03, 10M
●
Hydroxylamine Dissolve
hydrochloride
(NH20H”HC1) solution,
69.5 g of reagent in 200 ml of distilled
and warm if necessary
for dissolution.
FeCl , w2M.
Dissolve
40 g of reagent-grade
tetrahydrate
in 100 ml of 0.2M H(H.
glass
Store
111 g of compound in one liter
xylene.
E@@n3ent ●
Extraction
vessel
●
Hot place
●
Micropipets
●
Stainless
●
Counting
●
Meeker burner
steel
with
counting
mixing
plates
plate heater
- 138 -
device
water
in a dark
stoppered bottle.
Dissolve
‘v5M.
FeC12*4Hz0
2-Thenoyltrifluoroacetone-xylene :;olution,W.SM. grade
is
Chemica28)
HC1,
●
products,
elements
(TTA).
●
●
Extraction
of reagent-
●
Asbestos board
●
Sample carrier
●
Alpha proportional counter (or gamma counter)
l%etreatment If interferencesmay be present in salution
the Np
to Np(IV) and carried on ‘~1❑g of La pre-
Np is adjusted
tracer,
with
cipitated as the hydroxide. The hydroxide precipitates are dissolved in lMHNO~, and LaFs The
fluoride
and dilute
precipitates
is
are dissolved
there
to
is a greater
carry
in a few drops :Frm
While the extraction of Np(IV)
HC1.
usually very effective, HC1 should because
precipitated
be used whenever
tendency
Np(IV).
of 2M A1(NOS)S HNOI
iB
possible
to form extractable
Fe(III)
ion in the HNOSsystem. It is desirable chemistty
to
is employed.
❑ easure
the chemicrnl yield
A 237Np spike
is useful
wch
for determining
239Np ❑ay be used for dete:nuining
23gNp recovery;
if
237Np yield.
Procedure 1. Pipet a suitable aliquot of the swnple into a separator funnel or other extraction vessel, 2.
Adjust
the solution to lM HCl - llf NH20H”HC1- 0.25M
KI may be used as a reductant in place of FeC12, 3.
Mix the
solution
for
5 ❑in at ambient
temperature.
4. Add an equal volume of 0.5M ITA and mix for 5. Allow the phases phase
and discard
to separate; it. 139 -
then
10 ❑in.
remove the aqueous
FeCla.
6.
Mash the organic
phase
IM HCl for 3 nin. discard T t.
the Np from the organic
equal
volume of 1CB4HIWs foL 2 min.,
strip
is too high last
traces
in g~
Ordinarily, negligible extract Fe is
activity
stripping A suitable
to s,~pa”tteand
by mixing
with an
(If the aqueous for alpha measurement,
Zr and Pa may be removed
of the
10M HNOs strip
solution
volume of ITA. the
self
small
amount of Fe in the ITA causes
absorption
is mounted directly a
phase
of radioactive
by a S ●in re-extraction with an equal
volume of
wash.
Strip
the
8.
k)ith an equal
AI1ow the phases
aqueous
the
by mixing
problem , excellent the Np into aliquot
strip
is prepared
alpha
counting
for
in counting,
and the
on the counting separation
TTA
plate.
is attained
If by
10M HNOs.
of the ITA extr;lct by conventional
or the
lrnethods for
237Np or gaiuna ,:ountinlg
- 140 -
10M HNOS
for
either ‘39Np.
Procedure
2.
OutZine
Separation of R. S. Dorsett15
N
by llA
Y
ofllethod
Np is determined in the presence and other acetone
Extraction
alpha-emitting
nuclides
(TTA) followed
of Pu, U, fission
by extraction
by alpha
counting
into
of- the TTA.
products, thenoyltrifluorol-he analysis
(1) the pre-extractionstep in which
consists of three parts:
acid and oxidation state are adjusted, (2) the extraction in which Np is quantitatively and alpha
counting
extracted
into
of the TTA extract.
cation is required, the
ITA, and (3) the mounting When additional purifi-
Np is stripped
fron
oxidation state are adjusted, and a second
the TTA, acid extraction
and
is done.
The precision of the method is dependent on the type and quantities of interferences. The interferencescaused by sulfate, phosphate, fluoride, and oxalate ions which complexes obtained
with
these
are eliminated
ions.
relatively
pure
A
hy addition
of A1(N03)?
coefficient of variation of 2% is solutions.
Reagenta â&#x2014;?
Hydroxylamine
hydrochloride
by dissolving
69.5
(NH20HoHC1), lM, is prepared
g of C.P.
grade
compound and diluting
to one liter. c
(NaN02),
lM, is prepared
compaund and diluting s
by dissolving
grade
to one litl~r.
2-Thenoyltrifluoroacetone-xylene, dissolving
69 g of C.P.
0.5M, is prepared
111 g of the compound in one liter
C. P. xylene.
- 141 -
with
by
e
Ferrous
sulfamate
solving
iron
[Fe(NH2SO~)2],
powder in an excess
minimum heating.
The solution
2M, is prepared of sulfamic is filtered
acid after
by diswith dis-
solution. c
Aluminum nitrate [Al(NOg)s), solving
2M, is prepared
grade
750 g of C.P.
by dis-
coml)ound and diluting
to
one liter. ●
o
(tlNOs) nitric
acid
from C.P.
grade
Collodion
solution,
solutions
arl? prepared
as required
stock. 0.5 mg/ml,
LS preFlared
by dissolving
S00 ❑g of collodion in one llter of l-to-l ethyl alcohol. ethyl ether. E@ipmen:! ●
Centrifuge
cones
(with
caps)
●
Vortex
●
Micropipets
●
Stainless
●
Counting
●
Meeker burner
s
Asbestos
●
Sample carrier
o
Alpha proportional counter
o
Alpha pulse height analyser
mixer
steel
counting
plate
plate:;
heater
board
Pretreatment FZuotide present La(OH)J.
in the
method. solution,
The hydroxide
When it is not knc}tin what impurities Np(Pu)
can be caxrier precipitated
is dissolved - 142 -
in HNos, and La is
are with
reprecipitated
as the fluoride.
The fluoride precipitate con-
taining the actinides and lanthanidesis dissolved in A1(NOS)3 and dilute
HN03,
and this
is extra:ted with 77A.
solution
@ in Mbut~Zpho@uzte
(TBP).
If Np :.s present
in TBP or
other organic extractants, it is stripped w:.thdilute HN03(%0.1M) and
then
analyzed
Sepamtion
by the
ofNp
procedure.
and U.
Acid control is very important for
this separation. In the analysis of low-level Np solutions that contain large quantities of U, the prcblem is complicated because 237Np and 230U have the same alpha energies. Also, the specific activity of 2ghU is 10 times greater than 237Np. Pm accurate analysis is assured by (1) close control of .:heextraction acidity, (1 tO.lM), (2) a double a fluorophotometric
extraction
cycle,
and (3)
in extreme
cases,
of U content of the final â&#x20AC;&#x2DC;lTA
determination
extract.
.%oaedme 1. Pipet 103 to 104 dis/min alpha of 29;Np into
a lS-ml
centrifuge cone. .. Add sufficient water or HN03 so that
at the end of Step 3
7
the acid is lM. Mix. 3. Add 1 ml of 2M Fe(NHzSOq)z solution. Mix and let solution
stand
for
5 min.
4. Add 3 ml of O.SM ~â&#x20AC;&#x2122;A in xylene, and mix for vortex
s.
phase,
5 min in a
mixer.
Allow the phases phase
the
to separate;
and discard and mix for
it.
then
remove the aqueous
Add 4 ml of lM HIXls to the organic
2 min in the vortex - 143 -
mixer.
6.
7.
If the alpha proceed
to Step 9.
proceed
to Step 7.
Remove the
due to F% and U is <103 dis/min,
activity
If the alpha
aqueous
5 min in the vortex
❑ixer.
Discard
phase.
the organic
9. WITI on the counting Id place
a clean
is >lOs,
from Step S and discard
phase
Add 1 ml of 8M HW3 to the
8.
activity
organic
phase,
and mix for
Repe~t~Steps
plate
heater,
stainless
steel
heat
it.
2 through
5.
to 175° to 190”C,
counting
plate
on the
heater. 10.
Pipet
an aliquot
%103 dis/min the pipet plate. 11.
Heat
12.
Np, and add it
twice
the
plate
xylene,
over
until
phase
droptiise
Place
that
contains
to the plate.
and add both
rinses
Rinse to the
dry.
a Meeker hurler
red color.
the :~late
flame until
the plate
on an asbestos
to cool.
Uhen the plate the surface. before
with
Heat the plate
is a dull board
from the organi.:
is cool,
add 1 dr.)p of coilodion
Allow the plate
counting.
- 144 -
to dry several
to cover minutes
Procedure
Detenninatlon of 23gNp fn Sanples U, Pu, and Fission Products
3.
H.
Contalnfng
Smlth3k7
L.
Introduction The procedure for determining 23gNp affords excellent decontamination from milligram quantities of
U,
the
fissim products
obtained from 1013 fissions, and Pu. The decontaminationfactor for Pu is about 104. An initial fuming with H2SO~ is required to ensure exchange between
the
U(WI] .
If the sample is a dissolved U foil, HN03 must be added
237Np tracer
employed
and 23gN11,and also to complex
before the fuming step to convert U to the VI oxidation state, NPIIV) and (V] are carried by LaFg precipitations
in the presence
of Zr and Sr holdback carriers. ‘l%epreci~itationsprovide decontaminationfrom the activities of Zr and Sr as well as from IJ. LaFs scavenging
with
Np in the VI oxidation state decontaminates
from the lanthanides md partially from Pu. The chemical yield is about 50%, and eight samples can be analyzed in one day. Reagen ta ●
La cnrrier: 5 mg La/ml, added as La0J0J)3. 6H20
●
in
H20
Sr carrier: 10 mg Sr/ml, added as Sr(N03]z. 4H@
in H20 10 mg Zr/ml,
added as ZrOC12 in H2C)
●
Zr carrier:
●
237Np standard solution: S,000 ta 10,000 in 2 to 4M HC1 or HN03 - 145 -
counts/(min-ml)
O.lM;
2M; concentrated
●
HC1:
●
H2SO~:
concentrated
●
HN03:
concentrated
●
H3B03:
saturated
●
HF:
●
HI-HC1: 1 ml 47% HI + 9 ml concentratedHC1
●
HF-HN03:
●
NH20H*HC1: SM (or saturated)
●
KMnOk: 10% solution
●
NHbOH:
concentrated
●
“Dowex”
1-X1O anion exchange resin:
solution
1:1 H20 and concentrated
equal
parts
HF
by volume of 2M solutions
100 to 200 or 200 to 4n0 mesh, slurry in H20* %ocedure Step
1.
Pipet 1 ml of 237Np standard into a clean 12S-ml
erlenmeyer flask, and then
pipet
in the samrle. Wash down the
sides of the flask with a little H20, add IC drops of concentrated H2W4,** and evaporate nearly to dryness on a hot IPlate. (No harm is done if the solution is permitted to evarorate to hard dryness.) Step of 2M I+Cl.
●
Dissolve the residue by boilirg briefly in a minimum Transfer the solution to a clear 40-ml Pyrex centrifuge
The resin is supplied by the Calif.,
●
2.
who purify
and grade
Bio-Rad Laboratories, Richmond, the resins manufactured by the
Oow Chemical Co. * [f the s~le has been obtained from more than the equivalent of 50 ❑g of soil, do not add any H2SOk sj.nce CaSOh will precipitate and carry NP to some extent.
- 146 -
tube;
wash
the tube.
once
wit
the washings
the
fla>..
The
volume of solution shou:.dbe 5 to 10 ml.
H20,
and transfer
to
(Ignore
any small residue.) Step
3.
Add 5 drops of La carrier and 3 drops of Zr hold-
back carrier. Add 2 drops of NH20Hâ&#x20AC;?HCI for each ml of soIution, stir, and Iet stand for a few minutes. Add HF dropwise until the yellow color of the solution disappears and the solutio.1becomes cloudy (LaFJ). Centrifuge. Remove ant discard the supetmate. Wash the precipitate Step
4.
with
1 to 5 ml of HF-HN03,
Dissolve the precipitate by slu:rryingwith 3 drops (Ignore
of saturated H3B03 and adding 3 drops of concentrated HC1.
any small residue.) Add 3 ml of 2M HC1 and precipitate La(OH)g by adding about discard with
1 ml of concentratedNH40H.
the
supemate.
several
milliliters
Wash the precipitate of H20.
Centrifuge
Centrifuge, t)y boiling
and it
briefly
and discard the
supernate. step
5.
Dissolve the precipitate in about 5 ml of 2M HC1.
Reprecipitate LaF3 by adding 10 drops of HF; centrifuge, and discard the supemate. If the precipitate
Wash the precipitate
volume is greater
with
1 ml of HF-HN03.
thwn 0.2 ml, repeat the
hydroxide and fluoride precipitationsuntil the volume of LaF9 precipitate
does not
exceed
0.2 ml.
- 147 -
Step
6.
Dissolve
the
fluoride
saturated
H3803 and concentrated
and allow
to stand
for
S min.
precipitate
in 1 drclp each c:f
HNOg. Add 10 drops Add 2 drops
of KMn(lq,
of HF, and allow the
solution to stand for a few minutes. Centrifuge, and transfer the supernate to a clean centrifuge tube. Wash the precipitate with
1 ml of
previous
Step
HF-HN03, Discard
one.
7.
centrifuge, the
and add the
supernate
to the
precipitate.
Add 2 drops of La carrier to the sclution, stir.
centrifuge, and transfer the supernate to :1clean centrifuge tube. Wash the
precipitate
with
1 ml of 1{1:-HN03, add the
washings to the previous supernate, and di!;cardthe prec:Lpitate. Step
u.
Add 5 drops of NHzOH*HC1 and 2 drops of Zr carrier,
and let stand for a few minutes. Add 2 drc~psof La carrier, stir well, cent.rifugepand discard the supernatc. Wash the prec~icate with 1 ml of HF-HN03, centrifuge, and discmd the supermtc. Step
Step
9.
Repeat Steps 6 and 7,
10.
Add 5 drops of NH20H-HC1 ard 2 drops of Sr hold-
back carrier, and let stand for a few minwtes. Add 2 drops of La carrier, stir well, centrifuge~ and discard the supermate. Wash the precipitate with 1 ml of HF-HN03, centr:Lfuge,and discard the supernate.
- 148 -
Step
11.
Dissolve the precipitatewith 1 drop of saturated
H@C)3 and 10 drops of concentratedHCI. Pass the solution through a “Dowex’” 1-XIC) anion exchange column, 3 crIx 3 mm, and wash the column with 1 ml of concentratedttC1. The Np, now in the
It’
oxidation state, is sorbed on the column. rf necessary, remove Pu from the column with H1-HC1.+ Add applm~ximately1 ml of O.lM HCI to the reservoir of the column. I)iscardthe fi:rst2 drops that come off the column, and then collect approximately0.2S ml in a clean, dry centrifuge tube. Use no aLr pressure when eluting the Np.
Pick
up the solution in a transfer pipet and evaporate
by stippling on a 2.5 cm Pt plate. If possible keep the deposit within a 1.3 cm circle. Flame the sample to duI; red in a burner, mount with double-sided Scotch tap~ in the center of an Al plate, and a- and $-count on 3 successive da:?:;.** ..——.
* The procedure should remove 9S% of the F’uinitially present in the sample. If, at this point, there remains enough Pu to interfere with the determinationof the Np yield, that is, more than 1% of the Np tracer, Pu may be removed more efficiently in the following way: Allow 1 ml of HI-HC1 solution to drip through the column with no added pressure. Wash the column with several ml of concentratedHCl, and discard the effluent, which contains Pu in the III oxidation,state, and proceed with the rest of Step 11. One elution step such as the one just described removes 99,5% of the Pu. *“ Alpha-counting: The sample is counted in a 7.5 cm id. methaneflow proportional counter with a loop :.node,~perateclin the a-pllateauregion. Beta counting: The sample is placed on the third shelf of a methane-flowproportional counter with a window thickness of 4.8 mg/cm2. An absorber (about 5 mg A1/cm2), placed on the first shelf, stops soft lletasand alphas. The individual counts are corrected to to,,using a half-life of 56.6 hr, and are then averaged.
- 149 -
Procedure
4.
Determination Landrum34e
of Np
J.
Outline After
of Method the sample
evaporation.
is dissolved,
the vo~,ume is reduced
by
Np and other hydroxides are precipitatedwith SO%
NaOH to separate Al. The precipitate is d:.ssolvedin concentrated H71, and Np is separated from many impurities by chloride anion exchange. Further separation is attained by performing in order: ITA extraction, cupferron extraction, and {:hlorideanion exchange. The plate for counting is prepared by electrolysis. Reagent8 ●
50$ NaOH
●
in La carrier, 5 mg La/ml (as La(NO:l)g06Hz0
s
Concentrated HC1
●
55% HI solution
●
HC1 gas
●
Bio-Rad AG 1 x 8, 50 to 100 mesh resin
●
10M HC1 - O.SM HI
●
5M HCl
●
lM HCl
●
0.4M lhenoyltrifluoroacetone(TM) in xylene
●
6% Cupferron
●
CHC13
●
Saturated NHkCl solution
●
ConcentratedNH@H
-
150 -
H20)
l+ocedure 1.
237NP stan-
To the sample add about 3 x 10: alpha counts/rein dardized
(no inhibitor), reduced cient
Add W2 mg of La3+ carrier
tracer.
and boil
to about
the
sclution
Transfer
10 ml.
until
bath,
centrifuge,
the volume has been
to a 40-ml cone.
SO%NaOH to dissolve any Al that
in a water
and 2 ml S5% HI Add suffiHeat
may be present.
and discard
the
supematant
1iquid. 2.
Wash the
precipitate
centrifuge, with
Dissolve
thoroughly
and decant. the precipitate
salts
the
precipitate, solution
column,
in 10 ml of concentrated
HC1.
of 55% HI (no inhibitor).
Cool and saturate the
Again heat,
30 ml of H20 (to remove most of the Na+ salts),
Add 2 drops 4.
Wash the precipitate
and decant.
centrifuge, 3.
10 ml of 10M NaOH.
with
centrifuge
through
6 ma I.D.
HC1 - O.SM HI. be measured,
solution
with
HC1
(If
gas.
Pass
them and decant.)
a “Dowex” l-X8,
white
50 to 100 mesh
by 11 cm, pretreated with concentrated Discard
save the
If 23tPu is to
the effluent. effluent
and note
the time of Np-Pu
separation. 5.
Wash the column with
15 ml of IOM HCl - 0.5M HI, and
collect the wash with the effluent. 6.
Elute the Np with allow eluate
7.
a minute
three
S-ml portions
or so between
in a 125-ml Erlenmeyer
Add 2 drops
HI , and boil
a 40-ml cone with
elutions.
15 ml.
151 -
Collect
the
flask.
to ne~.r drfless.
lM HC1.
-
of 5M HC1, and
Transfer
to
Add lM HCl to ❑ake approximately
8.
Add 10 ml of 0.4M ITA in benzene, and equilibrate centrifuging, clean
30 ❑in.
for
,Soparate
and transfer
40-ml cone.
0.4M ITA for
or xylene,
the
the organic
Repeat
10 min.
toluene,
layers
layer
the extraction
by
into
with
a
5 ml of
Combine I:heorganic fractions.
Discard the aqueous fraction. 9.
Wash the organic fuge,
10.
and discard
Back-extract and transfer
10 min.
with
aqueous
phases.
To the
combined
Discard repeat step
the
to a clean
phases,
aqueous
the CHC13 (lower
the
Centri-
the TTA with
1 ml of 9M HC1 for
layers
as before,
cone.
Repeat
S min.
Equilibrate
the
Combine the
add 2 drops
layer).
2 ml
of 6% for
30 sec.
Add S ml of CHC13 and
Again discard the CHCIZ.
the extraction.
12. Transfer
Separate
and 5 ml of CHC13.
is designed
2 min.
the aqueous.
the aqueous
extraction
cupferron
5 ml of IM HC1 for
the Np by equilibrating
of 9M HC1 for
11.
with
to remove trou~lesome
solution
This
Nb activity.
to a 125-:nl Erlwuneyer
flask,
add 1 ml
concentratedHNOS, and boil to near dryness. Add 5 ml of 9M HC1 and 1 ❑l of concentrated reaction
between
HNOSand formic
acid.
acid
This
step
oxid:.zes
(CA~ION:
may be violent
Warm th(g solution
much HN03 is present.) been destroyed.
fo:nnic
until
The if
the HN03 has
U(VI) and reduces
Np(IV) . 13. Add 5 ml of fresh should
be >1OM, use HCl gas if
solution I.D.
concentrated
through
pretreated
5 ❑l of 10M HC1.
wash.
- 152 -
HC1 concentration
necessary).
a “Dowex” l-X8,
x 5 cm column,
column with
HC1 (final
Pass the
50 to 100 mesh,
with Discard
10Y HC1.
too
6-mm
Wash the
the effluent
and
14. Elute the Np as in Step 6, but with 10 ml of SM HC1. Collect
in a 125-ml Erlenmeyer
1s.
Repeat
Steps
16.
Examine on a NaI detector the sample
flask. (ITA extraction)
7, 8, 9, and 10.
for ganm
is radiochemically
pure,
contamination. If plate
the
sample.
Electroplating 8oil
the solution
NH40H and
with
solution
red.
diameter cell
lM HC1 so that
(Volume should
to an electroplating
the
Pt disc for
cell
fitted
with
Add 1 ml of and adjust
one drop of lM HCl turns Transfer
a Pt hire
the
the
solution
anode and a l-in.1.5 amps through
15 min.
solution
Continue
counter.
If appreciable
procedure
without
Dismantle
the
NHkOHto the cell
plating
from the cell,
count
red indicator,
Pass approximately
cathode.
is in progress.
alpha
dryness.
be 3 to 4 ml,]
Add I ml of concentrated
the
10 to near
NHtiCl and one drop of ❑ethyl
saturated acidity
from Step
for chemical
another
electrolysis
15 to 30 sec.
Remove
and check it for activity in a well
activity
the addition cell,
for
while
is present,
repeat
the plating
of NH4C1.
flame the yield.
Pt disc
to a dull
Gamma and beta
count
red, for
and
23gNp
and 290Np. Notea 1.
Using this procedure, Np is separated from solutions whose contents
underwent
10 15 fissions
up to one gram of dissolved
soil.
[one week previous)
(:amma-ray spectroscopy
showed no activities Other than 23eh’pand 23gNp, - 1s3 –
and
2.
10 to 12 hours
3.
The yield
for
is required this
procedure
for
six
samples.
is 30 to 60%.
- 154 -
.-. .
‘ocedure
5.
Determination
L. J. titZine
of
Slee,
Small
Amounts
G. PhIlllps
of
Np in
Pu Metal
gnd E. N. Jenklns320
of Method
Pu metal
is dissolved
in HC1.
The Np (lCI to 2000 ppm) is
parated from Pu by 7TA extraction
and determined
with
a square-
ve polarograph, Retzgenta ●
Distilled
water
●
HN09, analytical-reagent
●
Hydroxyamine
●
‘lTA solution,
gradt
hydrochloride 0.5M in xylene:
thenoyltrifluoroacetone filter,
and dilute
●
Ferrous
chloride
●
EDTA solution: tetraacetate with
(NFzOHOHC1)solution, Dissolve
28 g of 2-
(lTA) in 200 ml of pure with
xylene
5M
xylene,
to 250 ml.
(FeCIZ) Dissolve
37 g of discldiu.m ethylenediamine-
(EDTA) in distilllsd
ananonia solution,
water,
and dilllte
adjust
to pH 7
to 100 ml.
Piwoduw
1.
Weigh %300 mg of Pu ❑etal
2.
Add S ml of distilled 1(M Hcl.
Dilute allow
and then
slowly
subsides,
5M NH20H*HCIand warm the
to 10 ml with
distilled
5 min for oxidation
Transfer
4.
water
When the reaction
and 2 ❑l of
3.
accur~.tely.
quantitatively
5 ❑l of O.SMTl’A.
writer,
state
add 1 ml of ICR14 HCl solution.
mdd 2S0 mg of FeC12,
djustmnt.
to an extracticm vessel, and add Stir
for
10 minutes,
allow
to separate, and remove the organic phase.
-
.
.
add 0.5 ml of
1s5 -
the phases
5.
Repeat
the
extraction
15. Combine the organic
with phases
S ml of (),SMTTA. in the extraction vessel, add
1 m.1of I.MHCI, and stir for 1 min (to remove entrained Pu. Remove the aqueous phase. ‘7.
Add 5 ml of 10M HN03, and stir for I.(1 nin t~ strip the Np.
13. Remove the aqueous phase into a clear,vessel, and repeat Steps 7 and 8. !3 . Evaporate the 10M HN03 to m3 ml and then add 5 ml c~f analytical-gradeconcentratedHN03. 10. Evaporate!to W1 ml, and repeat evaporation with twc}more 5-ml.portions of concentratedHN03. 1:1 . Add 3 ml of analytical-gradeperchlcn’icacid (6C%) and more concentrated HNOS and evaporate to complete wet oxidation of organic matter.
1.2.
Heat until solid perchlorates remain “but do not
bake.
13. Dissolve the residue in 1 ml of warm 6M HC1 and 1 rnl of water. 15.
Add 2 ml of 5M NH20H=HCl and evaporal:eslowly to ‘W.5 ml.
15. Add 0.5 ml of lM EDTA and 4 to 7 dro~~sof armnoniato adjust p}{to 5.5 to 6.5. 16. Dilute to 5.00 ml, and mix thoroughljr.Transfer 2.,00ml to a polarograph cell, and de-aerate with N2 (pre-saturated with water) for N3 min. 17. Record
the Np peak at about -0.8 V al~ainstthe mercury-
pool anode on the square wave polaro~:raph. 18.
Add ‘vO.2 ml of a standard Np solution prepared in EDTA so that the original peak height is ~~pproximately fioubled. Deduce the Np concentrationof the o:?iginal
- 156 -
solution
from
the increase in peak height, Interferencefrom the oxidation of chloride ions is decreased by adding EDTA to shift the half-wave potential of tho Np peak. The precision is t2 and tlO% for concentrationsof S00 and 25 ppm, respectively.
- 157 -
Procedure
6.
Determination of Np in Sample Containing Products, U, and Other Actinfdes A.
Ffssfon
Schneiderlgk
Intro&Wion This procedure method for
separating
products using
describes ~
an analytical.
solvent
extraction
from Pu, Am, Cm, lJ, TII, and fission
tri-iso-octylamine
(TIOA) and thenoyltrifluoroacetone
(TTA). Np is separated from Pu, Am, Cm, and fission products by extraction of Np(IV) into reducing
Further
agent.
the
amine from iiN03 containing
purification
is obtained
a
by stripping
Np from the amine with dilute HCl ani then extracting the Np into TTA. Reagenta ●
5M HN03
.
3M [Ferrous Sulfamate], Fe[NH2SO:)2
●
5.5M [hydrazine],
.
10 Vol% tri-isooctylamine
●
lM HCl
●
5M [hydroxylaminehydrochloride] (NHzOH=HC1)
●
0.5M TTA in xylene
N2H4 [TIOA) in xylene
Procedure 1.
To a 5-ml extraction glass-covered
2.
Pipet
vial
magnetic
the sample
add 1.5 ml of 5M HN03 and a
stirring
(not to exceed
and stir.
-
158 -
bar. 200 DE) into
the HN03
3.
2M Fe(NH2S03]2
Add 3 drops
Stir
and allow
to stand
1 drop of 5.5M N2H4.
and
for
.5 min at room temperature.
Add 1.0 ❑l of 10% TIOA in xy.lene and stir
4.
s.
Allow the phases
produce
an emulsion.
Separate
the phases,
and discard
Transfer
the organic
phase
clean
vial
containing
Fe@H2S03)2, allow
from the
to separete.
original
1.5 ml of SM ~03,
to separate,
3 min to
the aq~eous.
and 1 drop of N:H4.
the phases
for
Stir
vial
3 drops
a
to
of
for two minutes,
and discard
the
aqueous
phase.
6.
Transfer vial
exactly
containing
Rinse
the
ml of the organic
0.7S 2.5
0.75-ml
pipet
7.
the organic
Transfer clean
2M Fe(NH2SOs]z. from the bath, 8.
the phases
Stir
and heat
and let
stand
emulsion.
HC1
phase
to a
of 5M NH20H”HC1and 3 drops at
for
Add 1.0 ml of 0.5M ITA in xylene. a complete
to separate.
phase.
Add 3 drops
vial.
a clean
in t}e xylene phase of the new
2.0 ml of the aqueous
exactly
to
ml of IM HCl and 1.5 ml of xylene.
vial. Stir for 3 min and allow Discard
phase
65°C
for
3 min.
of Remove
3 min. Stir
Allow the phases
for
4 min to give
to reparate.
The
organic
phase contains the purified Np. This phase is
❑ounted
for
alpha
counting
for measurement
of 2q7Np.
Notes 1.
The presence lower the
of fluoride,
coefficimt
extraction
Chloride
ion does not
of these
anions
size
or by adding
sul~ate,
interfere.
is circumventl:d Al ion.
- 159 -
tixalate,
of Np(IV)
and phosphate
into
The deleterious by reducing
TIOA; effect
the sample
2
!,
For U-tree samples,
the combined system yields 96 t2%
recovery. For U-bearing samples, the!recoveries are dependent on the amount of U taken, ~â&#x20AC;&#x2122;heextraction conditions are reproducible,and for control analyseis the 3.
recovery
factors
are
included
in l,he calculations,
In routine use, the combined e~tracti{m a separation
from common fission
Zr, C% and Sr) of about
prodticts
system
achieves
(Cc, Ru, Nb,
1 x 106 and :aPu separation
factor of 5 to SO x 10s. 4. Control of the method for samples of lmknowr composition is maintained by spiking a portion of the sample solution with 237Np or 219Np and evaluating th~ recovery of the spike. An alpha pulse height analysis may be necessary if large amounts of Pu are initially present in the sample.
- 160 -
Procedure
7.
Determination Products
of
Np fn
Samples
W. J. Maeck G. l.. Booman, E. Rein’J’
H.
of [.
U ond Fission Elliott,
and
J.
Introduction This procedure determination methyl
a method for
of Np in solutions
isobutyl
Np is oxidized
describes
ketone
separation
of U and fission
products
and thenoyltrifluorom:etone
to the hexavalent
state
and using
(TTA) e,xtractants.
and qllantitmtively extracted
as a nitrate complex into methyl isobutyl ke:one from an aciddeficient
A1[N03:)3 solution
Np is stripped and
then
containing
from the ketone
quantitatively
with
extracted
tetral]ropylammonium lM HCl c{mtaining 7TA-:qrlene
into
nitrate.
reductants
to complete
separation. Reagente Al(N03]lJ
salting
A1(N03)3”9Hz0, mixing,
solution:
1050 g of
add 13S ml of conccrltrated
and cool
to SO°C.
itetrapropylanmnonium until
ail
solid
solution
to one liter
reagent,
is dissolked.
and stir Dilute
the the
with water.
solution:
().25M FeCIZ solution. 0,>2SMKMn04 Methyl isobutyl ketone (),5M‘lTAin xylene Ethylenediamine
-
NH401{with
Md SO nii of 10%
hydroxide
solution
Reducing-strip
Dissol\’e
161 -
IM HI - C,,5M NH@H”HCl and
the
Pmuedure 1,,
Add 6 ad of A1(N03)s
salting
:}f~lution
0.1 ml of 0.2SM KMnOK. Then p:,pet
to a tube
containing
1 ml or loss of the
sample into the tube and mix. 2.
Add 3 ml of methyl isobutyl kel:one,
3“
Centrifuge
4.
Remove 2 ml of the organic
to separate
and mix for
3 minutes.
the pha:~os. ph~a:se, and transf(m to another
tube containing 4 ml of the rmlucing strip solution. MiX for 10 ❑in and allow 5,,
Transfer
the phase~
3 ml of the aqueous
funnel;
to separate.
lp!lase tcl a 30-ml separator
add 3 ml of 0.5M TTA, md stir
vigorously
for
10 min. 6.
Let the phases separate, and discard the aqueous
phase.
Add 3 ml of reducing-stripsol~tion, and scrub far 5 minutes, 7.
Remove an aliquot counting
plate
of the organic
under
phase,
and dry it
on a
a heat lamp. Cover the residue with
2 to 3 drops of ethylenediamine,evaporate to dryness, ignite, and count.
1,
Extraction isobutyl
from acid-deficient ketone
extraction Ru and Zr,
2.
used
for pulse
80-day
separated
scintillation
and a Frisch-grid
good separation
of U and Pu is
the only
Np, are
An alpha
very good separation
with ‘lTA gives
The extraction follow
yields
A1(IW3:1)3with methyl from Pu and U.
cO.1 and 0.01%,
cooled
fission
respectively,
products
that
by >10”. counter
chamber, height
from Zr, and
2S6-channel
analysis.
- 162 -
is used
for gross analyzer
counting, system
is
8.
procedure
ExtractIon ChromatoqraDhic Semlratiorl of 23*ND From Fission and Activation P~]ducts in the “ Determination of Micro and S@nntc~gram Quantities of u
H. Wehnar,
●nd H. Stoeppler2s2
S. A1-Nurab,
Int2vduotion
procedure
This
tion
describes
Of ‘s’Np from fisAion
irradiation.
easily
It
analyzed
chr~tographic
and activation is Poropak-Q
The system
lTA-xylene.
extraction
is suggested
that
with extraction
prtiucts
resin
separa-
after
impregnated
radioactive chromatography
neutron with
samplles are more than with lTA
extraction. ReagentB ●
Poropak-Q
resin,
100 to 120 mesh
●
0.4PI ITA in xylene
●
2M W1
●
lM FeC12
●
3M NHzOH”HC1
●
10M HIW3s
(~mall
amount of n-pentane
added)
P2wmchlw? 1.
Dissolve
sample
in 2M WI or convext
to c~hloride
with
HCl . 2.
Md 3 ml of freshly NH20HoHC1■ix,
and
3. Transfer the adjusted
prepared let
stand
lM FeC:lZ and 4 ❑l of 3M for
1!, min.
solution to a column
0.6 cm I.D.) of Poropak nt W1 ■l/(-2.min)C
Q impregnated
- 163 -
with
(S cm long and ‘lTA-xylene
4.
When the feed has passed 2 â?&#x2018;l of lM HCl and then Discard
througlh
Pass
a few dr~~ps of distilled
S ml of 10M HNOSthrough
6.
Count the HN03 solution nected
wlzsh with water.
the effluents.
5.
after
the column,
separation
tlw! column to strip
containiltg
with
the
a 3 x 3 in
to a S12-channel
23gNp immediately
NaI(TL)
pulse-he:!ght
the Np.
detector
analyzer
con-
md evaluate
the 0.106-MeV photopeak. Not%e 1. The method was suggested for det[mnining low concentrations content mining
of U by irradiating at the the
a stan{lard
same time as the Imknown and then
23gNp content
of both
of 1 pg of U was determined at a thermal
sample of known U
neutron
flux
samples.
for IL%1 hour
A
WilUh
with a
a longer imadiation,
a detection limit of 0.S ug is sllggested.
- 164 -
sensitivity
irradiation,
of 2 IC 10]3 n/cm2-sec
cooling period of â&#x20AC;&#x2DC;K!Ohours.
deter-
Procedure
9.
Separation of Phase Partition
U,
Np, Pu, and Am by Reversed Chranatogruphy
H. Eschrlch240 Introduction This procedure tion
describes
extraction
chromatographic
of U, Np, Pu, and Am. The system
(diatomaceous and aqueous
silica)
impregnated
H?#lg solutions
Reagente
with
of the
is Hyflo
Super-Cel
tributyl
phosphate
separa-
(TBP)
actinidos.
and MateriaL3
●
Hyflo
Super-Cel
●
Purified
●
HN03
●
Sodium bichromate
●
Dichloro-dimethylsilane
●
Glass
tributyl
phosphate
solution
(TBF)
[NazCrzOT]
column
Rwceduw 1.
Add Na2CrzOT to
and heat
1 to 2M HNOs containing
at 75°C for
five
hours
the
t~ yield
actinides,
hexavalent
U,
Np, and Pu. 2.
3.
Wash the packed
column with ‘v1O column volumes
at relatively
high
and nonsorbed
TBP.
Md the
sample
flow and pressure
volume
(not greater
column volume and containing extractable
species
per
to remove any air
than
1/10 of the total
a ma(imum c,f 1 mg TBP-
100 mg of silaned
at a flow of 0.4 to 0.8 ❑l/(min-cn2).
- 16S -
of NIM HNO~
Hyflo
Super-Ccl)
4.
Wash the columm with Am(III), After
s.
wash.
Cr(VI),
Pu(VI)
1.7M H?U)3to remove (in order)
and Pu(VI).
elution,
switch
(Np 1s reduced
to 1.7M HNOSI- O.lM NzH4
to Np[V) and elutes
immediately,
and U(VI) is remved.) Nota
If U, Np, and Pu are present The feed NP(IV), The order
is adjusted
0.7M HNO, -
and UCVI), and the of elution
, no oxidation 0.02M
Fe(S03NH2):1
same composition
is Pu(III),
Np(IV),
- 166 -
step
is required. to
yield
wash !Jolution and U(VI).
Pu(III), is used.
Procedure
10.
An Analytical F.
Method
for
*s’lip
Usln9
AnIon
Exchange
Robertszlh
P.
OutLine of Method This products
method separates by anion
estimation tracer
Np from Pu, U, Am, Cm, and fission
exch~e
in HNOSsolutions
by gaama spectrometry.
to permit
yield
of “Oowex” l-X4
corrections
is :;piked with
and loaded
onto a small
After
volumes
Fe(NH2SOy)Z
eluted
recovery
with
dilute
is @5# with
Decontamination are all
interfere.
to samples Reagenta
(C.P.
semicarbazide,
factor
from U, Am, Cm, and gross
high
salt
Concentrated
●
w2M Fe(SOsNHz)z
s
Semicarbazide
●
2agNp tracer
fission
factcm
?~~wextf
●
Glass
1.x4,
column,
feed
12M HC1. - O.lM NH*1. The ❑ethod
COnCentratjLOnS.
HNOs
1oo-2OO mesh
0.3 cm x 7 cm wit!l 10-ml reservoir - 167 -
products
can be increased
MtZte2%Uz8 ●
Np
of 5 x 10”.
C’hmn%a28)
●
the
up to 180 g/1 in the
the HNOgwash with
containing
colum
30 to 40 column
0, 00SM Ce(SO~)z,
is then eluted with 6.5M HCI - 0.004M HF.
cable
with and
The Pu decontamination
10 to 100 by following Np
HNOs containing
Uranium at concentrations
>104.
does not
washing
a Pu decontamination
factors
2ssNp
from 8M HIW13containing
Fe(NH2SO~)2 and sem.icarbazide.
Np is
2Y7Np
The sample
(100 to 200 mesh) resin
of 4.5M HN03 containing
to permit
is appli-
●
Counting equip-n t
PJwf?ed3uw 1. Adjust
an aliquot
of sample
to ‘@N HNOs Mith concentrated
HFM33. 2.
Add an equal semicarbazide
volli .e of 8M HNOS - 0.02 Fe[NHzSOq)z - 0.2M and mix.
3.
Add 23$Np tracer (’vIOSdis/min).
4.
Pass the adjusted sample through the column at 3 to 6 drops/rein.
s.
Rinse the reservoir several times tiitha few drcps of. 8!4NNOs, pass through the column, md discard.
6.
Pass
1S to 20 ml of 4.SM HNOS - O.IM semicarbazide - O.OIM
Fe@H2.S03)2 through the column at .5to 6 drops per minute (’Pufrnction). 7.
Pass 2 ml of 8M HNOs rinse through the column.
8.
Elute the Np with 2 ml of 0.005M Catch
9.
the
~f!(S04)2
in
0.25M
WW3.
eluate in a 2-ml volumet~’icflask.
Mount an aliquct of the Np product on a Pt disc for alpha counting and alpha energy analysis. (The yield is determined by comparative counting of the 0.23 MeV 239Np gansnafrom the disc with that of a standard 239Np disc.)
- 168 -
Procedure
11.
of U, Np, and Pu Us-lngAnIon Exchan e D, C, Michelson, ●nd J. H. Holloway ?2,
Separation F. Nelson,
GutZine of Method This U, Np,
❑ethod
utilizes
exchange
anion
and Pu from “~m-adsorbable”
.n ml
elements
for
separating
which include
alkali
metals, alkaline earths, trf.val-,~t actinides, rare earths, and a number of other Sorption solutions not
elements
such as Al, Sc, Y, Ac, ‘I’h, and Ni.
of the uranides
can occur
in either
Np and Pu are
selectively remain
reduced
sorbed.
sorbed
to PuIIII)
The latter
exchangers
from HCl
the +4 or +6 oxidation In this
in the +3 or +5 states.
+6, while
by anion
pr,>cedurm,
in the +4 oxidation and elut:d,
are then
eluted
while
states
but
U is sorbed
as
state.
Pu is
UG+ and Np”+
in separate
portions
with HCl - HF ❑ixtures. Reagenta
(C.P.
ChmicaZe)
●
9M HCl
●
9M HCl
-
0.05M
●
4M HCl
-
O.lMHF
●
0.5MHC1 - lMHF
NH~I
Matefia2a ●
“Dowex”
1-X1O, -400 ❑esh anion
●
Column,
0.6 cm I.D.
and 12 cm in length,
device. ●
Resin
●
Plastic
bed, test
0.28 cmz x 3 cm long. tubes
- 169 -
.’.
.
resin with heating
e
“Teflon” evaporating dishes
e
Pl!astictransfer pipettes
i%ooedure :1,,
Evaporate sample to near dryne!ss.
‘) . ..
Add 1 ml of 9M HCi - O.OSM HNCl~and heat for S min. Do not boil.
3. -
Heat
4.
Pretreat
column
to
resin
50°
and maintain
throughout
elution.
bed with 3 colum~ volumes of 9M HCI.
Use air pressure to obtain flolwof (J.8cm3/min. 5. Pass sample through resin bed ac 0.8 c.mi’min. 6.
Wash bed with 4 coiumn volumes of 9M E!Cl.
7“
Wash bed with 8 column volumes {~f9M HC1 -
0.05M
NH41
(PLIfraction). 8.
Washi bed with 4 column volumes clf4M HC1 - 0.1,?4 HF (Np fraction].
9,
Wash bcd with 3 column volumes cf 0.5M HCl - IM HF (U fraction].
10. Regenerate the column with 3 column volumes of 9M IiCl. The total time for the column operation is about 80 min.
-
170
-
Procedure
12.
Outline This
Separation of Zr, Np, and Nb Us”lngAnion Exchange J. H. Holloway and F. Nelson224
of Method
procedure is used to separate trace mounts of Np and
Nb from micro-amountsof Zr.
It makes use of the fact that Zr(IV)
in HCl - HF media at high HC1 concentrationsi:jessentially nonsorbabl.eby anion exchange resin under conditions where Np(VI) and Nb(V) are strongly sorbed.
lkgenta
.
6MiHC1-lMHF-C12
@
6~~HC~ - 1~1HF
o
0.5MHC1 - 1.OM tiF
o
4M HN03 - lM HC1 - 0.2M HF
Matetiah e
“Jlowex” 1-XIO,
o
Column, 0.9 cm I.D. x 12 cm ir length containing 2 ml of
-400
mesh anicw resin
resin e
“Teflon” evaporating dishes
o
Plastic transfer pipettes
o
Plastic test tubes
a
Chlorine gas
Prccedwe 1,
Dissolve the sample, and evapcnate it to near dryness.
2, Add 1 ml of 6M HCI - lM HF - C12, and warm. 3, Transfer the sample to a plastic tube and bubble C12 gas through it for 53 min. - 171 -
4.
Chlorinate
the resin,
5.
Wash the bed with lMHF - Clz.
Then
pass
the
the flow with
When the
sample has passed,
Wash with
to the column.
2 column volumes
(Control
3.5 column volumes 6.
and add it
air
(â&#x20AC;&#x2122;U ml) of 6M HCI -
sample through pressure wash ~ith
at W.8
the
bed.
cm/min.
an additional
of 6M HCl - lM HF - Clz (Zr fraction).
3 column volumes
of O.SM HC1 - lM HF to elute
3 column volumes
of 4M FNOS - lM HCl - 0.2M HF
Np. 7. Wash with to elute 8.
Regenerate
Mb. with
3 column volumes
of 6M HCl - IM HF - Clz.
The total time for the column operation is â&#x20AC;&#x2DC;k30min.
-. 172
-
.
Procedure 13.
Separation of Np and Pu by AnIon Exchange Jackson and J, F. Short34g
N.
OAtZine of Method This and Np.
procedure
describes
separation
of macro umoâ&#x20AC;?unts of W
It is based on the fact that Pu(III) is not sorbed on
anion exchange resin, while Np(IV) is strongly sorbed at high HC1 concentrations. The valence adjustment is done before sorption on the column by dissolving the hydroxides in a concentrated HC1 solution that has been saturated with NHQI. The Np is removed from the column with 2 M HC1. The separation is quantitative and complete.
Bocedure The
purification of 2.3 g of Np237 from approximately 50 mg
of PU239 was then undertaken. The Np and Pu were precipitated as hydroxides, centrifuged, and dissolved in 210 ml of concentrated HC1 saturated with NH41. The solution 30 min and poured onto a Deacidite
was allowed
FF*anion
to stand
for
column 20 cm long and
2.5 cm diameter, while a flow rate of 1 ml/nin was maintained. The first 200 ml of effluent were pale blue [PU(III)]. The column was then washed with collected
100 ml of concentrated
separately.
No activity
HCl, and wash was
was found in a drop collected
at the end of the washing, The Np was eluted dark eluate
green
2M HC1.
It was possible to follow the
band of the Np down the column, and the first 4C pl of
was included
â&#x2014;?Deacidite
with
with
is supplied
the concentrated
by Permutit
HCl wash. All
Co. Ltd.,
- 173 -
England.
the Np
was, collected in the next SO ml of eluate. No activity w{asfound in any eluate
after
this stage. Some 6-Y :m:tivitywas detected
on the glass
wool at the top of the resin cf}lumnand was assumed
to be 2â&#x20AC;&#x2122;3Pa,
the daughter of Np237.
- 174 -
,,.,
Procedure
14.
!Separatfon
●nd L.
V. t). Zagrai Outline Np(IV9
i.
Exchange
Se14c1wMcov2’9
of Method ● re
and Pu(III)
adsorbed ●f~er
KU2 from 0.2SM }Kl solution water
Np and Pu by (hltfon
of
:eqeratures.
!#p is eluted
on tho
reduction with
cation
resin
with
KUl or
SOz at boiling
0.0i91HF,
and Pu stripped
with 0.5M HF.
P2%w31iu2w
C 9.2SN HCl containl,rg
1. To 6 tc)8 al &nd Pu,
2.
to fill
high]
Pass
the pleyfg!ass
and
1 to
Allou
the
ltransfer the
top
solutions
solution the
to cool
resin
to
of the CO1-
solution
4.
2 ml of
cc)]-
(1 IUSdiameter
water.
throug%
Wash the resin
the
with
the
heatinl
on a boiling
to room t~rature, CO]W
with cotton,
with
a pipette.
s.nd pass
water
IEIute the 40 to 60B1
6.
Np into
Plug
the remaining
CO1-.
10 ●l of 0.2S PI WI,
s Pt dish
or a *’7eflon”
of 0.02M HF.
iElutethe Pu with
bath.
mnd
follouedl
by 10
Is!i of H20. 5*
x
S(3Z gas through the solution tigorouBly for 1S to
,20rein,uhile the 3.
c~f Np
add a’~t half of the resir in the hydrogen fom
required !90 -
Dg mounts
4 to S ●i of ().5#1 HF.
- )75 -
beaker
with
Procedure
15.
Separation U and the Sulfate
and Radfochemfcal Iletermfnatfon of Transuranfu Elesmts Usfmg 8arfm
c. w. slll~23012*,125 Intrv&uth ions
Large trivalent and tetravalent Ea!50t
This
uhile mnomlent procedure
oxygenated cations into
the
the
iJa!Xl~
alpha
of
c~~ted
Cm
Ibe
the
radionuclidus Rmgmti
the
lattice
hexavslent
and
are
directly
with
ConC8ntrwed
perchloric
92% counting
●cid
hydrogen
dichremate p@roxido
(HClO~)
Erletmeycr
flask
Centrifuge
and special
Counting
s~lies
(K2CrzO~l]
(H203)
tubes
and qui~t
- 176 -
large
!kWt
to
fit
precipitate
efficiency, or
for ●lpb spectmametry.
KRO$
C.P. potassium
too
The
carried.
Kasm I’m)
30t
● re
HIS06
C0ncontr8ted
C.P.
not
state
E@gment
Concentrated
precipitated.
of U and tronsuranium
can be electrodqxmited d
C.!P.
separation
with
elements ●nd froa emch other. The
both from other
el-ts
cations are not
and diwlent
outlines
precipitated
~re
Prood4r6t 1.
Add 3 g of anhydrous 6 drops
each of concentrated
of 0.45~
solution
solution
containing
the
a 2S0-B1
Erlenmeyer
flask
HzSO*
(If
any
until
quc!;tion
in
fumes
H2SOb and lKIOti are melt
COIOI the
aelt,
tlCiO~ and re-svaporate.
volatilized
add
2 al
or until
the
and
of
concentrated H~SO*,
pyrosulfate’
melt
‘v40*C
t).
Cool,
centrifuge,
U are
in the
is dissolved.
the
Do not
Np.
of
excess
heat
becBuse
dichronate
will
%10 q
●nd Mash the
boil
precipitate;
and evaporate
H~SOb to
the
until
may have boiling, to
KtCr20T
Add ?0 ml of water and c~bine
I minute.
the
%p and
cool
for
!laClz to the
of H2!~Q appear the ?
to
Np.
minutes,
and ●dd
reoxidi:e the l~lJ.
●nd boil
supemate
and evaporate
ftmes
folloued
for with
Add 0.S ml of SO%tilOZ to reduce state,
for
supemate.
any Pu that
of
1% Mill
he the]~nlly
Md 0.S ml of SO% H~02 and 2.00 ad] of 0.4S’i
the
heat
KICrzOT,, and mix to ensure
●nd add ~20 IR1 of water;
Cool
Heat
and
.
%.
reduce
a clear
tsuch HzSO~.
cxidation
supernate,
until
is obtained.
Cool and add ~10 IDg of solid
to
of
removal
about
and
excess
decomposed
la.
be precipitated
evapo]’ate
ml
the
the
be oxidixed
9.
is
to
em) to
swirling
cmplete
8.
(S /rng of
●dd IWO] and/or
00 not volatilize
7.
mlkd HCICI~, and 2.00
elements
md
HzSO*,
Heat the solution over s blast burncIr with
to boiling
‘4.
My
8aC1202H2C)
there
Mtter$
pyrosulfate
.3.
of
appear.
of organic 2.
KzSO~ 2 ml of concentrated
to
2S ml.
- 177 -,
1 that
wilwte; ~rom
cool. Step
centrifuge, 6.
Np ~:o the quadrivalent
11. Cool and add BaCIZ; then boil, the
BaSO~ which contains
tively
in the
centrifuj~e,
TIN) U remains
2â&#x20AC;&#x2122;7Np.
the
wash, and mount quantita-
supernate.
Not88 1. Seweral
other
shorter
Np is to be separated 2.
Details
are
given
the precipitate a specially specially cedure alphs
reference
on a stainless
designed
fo]: Np are
from one or tl~o other
in the
designed
uses
procedures
steel
centrifuge counting
electrodeposition
spectrometry.
- 178-
~wticle disc
holhler
holder,,
given
when
cations. for
depositing
that
fits
andl also
An alternative
of th~! radiaâ&#x20AC;&#x2122;nuclides
into
into a profor
The Low-Level Radiochemica”l Determfnatiom of 237~p In Environmental Samples
Procedure 16.
R. W. Taylor3S0
Intro&40t~on Np, along exchange
with
Pu and U,is
to triisooctylamine
removed
(TIOA).
last
with
Uost environmental that the
will
extract
Fe will
easily
the
bu stripped
removed
will
contain
actinide
with
8M
4M HCI - O.OSM HF,
large
quantities
elesmts
into
the TIOA al.cng with
froa
from 8 N HCl by isopropyl
i!~ known to contain
first
O.SM HNO~.
saaples
with
element can be indi-
is sl:ripped
Np is removed next
HCl - O.OSM NH*I. and U is removed
Eac:h
Pu
viduall}-removed from the TIOA.
frcm 8M HC1 by anion
no Fe, the
TIOA,
Much of
Np, but
ether.
it
is
If tho sample
extraction
ether
of Fe
step
may be
otsitted.
decontamination
Final
emhange. pulse
?@ is
height
foliou
a 9TMp .Mve
final 1y electrodepositet
by solid
for rsdioassmy
ion by alpha
analysis.
When ths may
of Np is accomplished
saaple
the
contains
large
quantities
Np ●nd be elactrodepositccl
the same alpha
guished
from
neutron
irradiation
activity
is wry
one
time.
Tw-how
result
in 8 2“pU
another.
The
ba converted
Np can
of ~ “~.
activity
●t a flux
level
about
- 179 “
it
2S’U
and
be distiny~c~
to
Also,
to 2S’PtI will
some of
plate.
(4. 7S MeIV) and cannot
conversion
irradiations
on the
U,
energy
for verification low,
of
by
whwn the Np
decreas~s
the
counting
cd’ 1 x 10*S n/(cm2-see) 7 to
10 times
greater
thsn
the original
activity due to Np.
R6!agt?nt’% o
HN03, 16M, lM
o
HCl,
e
H202,
c
12M, 8M 30%
NMkOH, 1.SM f
●
KOH,
12M
●
8M HC1 -
NHuI: This rm~gent must be prepared fresh
O.OSM
Discard a:lyunusef reagent at the
just prior to use. end of the day. o
10% TIOA (triisooctylaminc): 10% vcilume/volumeTIOA in Clean
xylene. funnel
with
HNOs wash, the
half
reagent
its
b:y shaking
in a separator
volume OF 0.5M HN03.
and wash finally
cleaned -
the
TIOA in
with
a glass
distilled
Repeat
the
water.
Store
flask.
O.OSMHF
g
4M HCl
o
Isopropyl
*
“Dowex” 2-X8 anion
ether exchange
~!Od to 400 ❑esh
:rlasin,
PmudLir8 1“ Adjust
the
saaples
sample
to be analy:z(sd
may be dissolved
may be leached evaporated
to
with near
hot
to 8M HC1.
Soluble
irlsoluble
materials
directly; MM HCl;
dryness
and
aqueous brought
samples
may be
up in 8M W1.
The sample should be adjusted 1:0a ccmvenient volume of from 200 to 400 ml. 2!. Add S m: 80°C until
of 303 }1202 to the effervescence
!umple
ceaso:~.
room temperature.
- 180 -
wnd heat
COCJIthe
nt
about
sample
to about
3.
Transfer the sample to a 500-md separator an amount
of
funnel,
Add
TIOA equal to one-fourth the amount of
10*
Shake the funnel for one minute. the original sa~le. Allow the phases to separate, and drain the bottom (aqueous) phase. 4.
Add
Retain for other analyses.
10 to
20 ml 8M HCI (according to volume c~foriginal
sample) and shake one minute.
Allow phases to separate,
drain, and discard the aqueous. 5,
To strip Pu from the TIOA, add to the
separator
an amount of 8M HC1 - O.O”X NHu1 equal voluune of TIOA.
funnel
to one-half the
Shake one minute and then allow phases
to separate. Drain the aqueous and retain fcm Pu analysis. Repeat the Pu strip ~ith a fresh Flortionof 8M w]
- O.OSMNd~I.
Combine t$e two strips, and save
for Pu analysis. 6,
To remove Np from the
TIOA, ad(d to tho
an amount of 4M HCl - O.OSM HF equal volume of TIOA and shake phases
to separate, Repeat
W*
O.OSM HF,
stripped 7.
the
for
with
the
and combine
to one-half
the
tl~eaqloous which contains
a f:rl!sh
pmtion
two :s’:rips.
from the TIOA with
funnel
Allow the
o]ms minute.
and drain
strip
separatcry
of
41.! HCl
-
U can now be
0.!51d HNOs.)
Add an equal amount of 12M HCl 1:0the combined strips, and transfer to a clean separatt~ryfumnel. Add 2S ml isopropyl ether and shake
8.
the
separator
funnel
the
aqueous,
and retain.
with
safety
with
a fresh
Evaporate in
the the
Repeal: the
shaking.) ether ether
Drain
in accordance extraction
of ether.
aqueous
furnace
while
Disca]*d the
regulations.
a muffle
oxidize
frequentl:r
portion
(CAUTION: Vent
one m:lnute.
phase at
frornl Step
400*C fo]’ at
sample two or threo
-
181 -
times
7 to dryness.
least with
4 hours. 3 or 4 ml
Place Wet
16M HWS
and
evaporate 9.
to dryness.
a “Dowex” 2-X8, The resin
200 to 400 mesh, anion
bed should
the sa@e
passes
10 ■l
cell.
Rinse
water,
and
beaker
transfer
the cell
is
an additional
md waporate
to
Add 2 ❑l IM HKls dissolution.
to an dectrodeposition with
the rinse
2 ml of distilled
to the cell.
and add distilled
Add 2 ml of water until
full. the sample ●t 10 V and about
Electrodeposit three
After
dryms.
tD
to ensure
twice
cell,
pass
waporation.
the sa~le
the
exchange colm.
the Np from the COIUWI
Evaporate
and heat gently
1.SM NH@H to the
Maintain
hours.
1 and 3 during
the
200 mamp for
of the solution
pH
electrodeposition.
between
A: the end of the
electrodeposithn
period,
●dd 1 ml o:? 12M B21Hand plate
for
1 min.
the
, rinse
and
remove
Count
the
there
is
~ty
plate
of
U
or when there
version
of Z“Iq) to
●bsence
of
●
flux
is
“% the
~
verified
aaqsle
for
by the
- 182 -
little
In 2% by con-
irradiation. initial
approximately
of 1 x 1013 n/(cm2-see).
2g7Mp
directly.
is wry
by neutron
“%
If
i!; sufficient
can be) ●chieved
sensitivity
it.
analysis.
height
there
water
and flame
carI be ●ccoqlishd
increased
Irradlato
●ml if
U present
the presence
with distilled
Dry the plate
●lpha plse
by
radimssay
present,
cell
the plate.
no
present,
13.
Elute
Repeat the W3
●nd transfer
Cool,
12.
it.
of O.lM HC1.
to the sa@e,
11.
the column,
Md 2 ml of 1(MIHNOSto the sample, dryness.
through
with 5 ■l of &MlHC1.
through
5 ❑l of 8M ICl through
10.
evaporation.
be 50 m long and 6 m in diameter;
must be pro-conditioned
with
12M lKl
the
Repeat
the sample in 10 ■l of 8M HC1 and pass
Dissolve
it
Md 2 or 3 ml 12M HCl and
30~ HzOZ.
The
count. tm
hours ●t
A1lCIUtha plmte
to
cool
long enough
and to allow by alpha
pulse
necessary.
irradiation
decay
23 ‘Np to decay height
‘gepu now present if
to pemit
to 2s ‘Pu.
analysis.
Correct
by any originally
Calculate from the
the
activation
- 183 -
of induced
Pt activities
Recount the
present
the
amount of on the
amount of Np present formula.
plate plate, before
Prowdure
Radiochemical Procedure for tle Separation of Trace Amounts of 2g9Np from Reactor Effluent Water
17.
R. W. Perklns1s5
Intmduotion This procedure accommodates a relative:{ large volume of reactor effluent water, and emphasis is pla{csdon speed of separation and high radiochemical purity ratler than high yield.
%ocedure 1. Acid 20 mg of La carrier and S ml of concentrated
HC1 to
one gallon of reactor effluent water, and evaporate to %Sclml. 2.
Cool the solution, dissolve 0.25 g >f Fe@H2.SOJ]2, and let stand for S min.
3. Transfer to a 100-ml plastic tube, ~dd 5 ml of concentrated HF,
stir, and let stand S min.
4.
Centrifuge, and discard the liquid phase.
5.
Dissolve the precipitate in 20 to S0 ml of 1?4HCl, and dilute to 75 ml with IM HC1.
6.
Add 5
ml of concentrated HF, stir, and let stand for
S min. discard the liquid phase.
7.
Centrifuge and
8.
Repeat Steps 5 through 7.
9.
Transfer the precipitate to a 50-ml beaker containing 3 ml of concentrated HC104, and evaporate to dryness.
1.0. Dissolve!the residue in 20 ml of lM HC1 by boiling. Cool the solution and dissolve 0.2S g of Fe[NHzSOg]z. Il. Transfer the solution to a 12S-Ialseparator funnel and mix,
Add 20 ml of â&#x20AC;&#x2DC;ITAin benzene, and extract fcm 10 min.
Discard the aqueous phase. - 184 ..
12. Wash the organic phase with three 20-ml portions lM HCI for
5 min each.
Discard
the aqueous
of
solutions.
13.
8ack-extract the 2S9NP with 10 ml of 8M HN03 for 10 min.
14.
Place
the
aqueous
concentrated ,leat 15.
in
a SO-ml beaker
and evaporate
HC104,
containing to dr:yness
3 ml of under
a
lamp.
Cool the
beaker,
add %5 ml of 8M HN03, and heat
to
boiling. 16.
Dilute
the
solution
to a measured
volume
and analyze
gaama counting.
Note
The analysis
requires
ti
hours,
-
18S -
and tle
yield
is
~90%.
by
Procedure 18.
Detennlnation of Np In Urine E. Butler3s J
F.
Outline
o~lfetbd
Urine is wet ashed with HN03 and H202 to destroy organic matter. The salts are dissolved in BM HCI and extracted with TIOA (tri-isooctylamine). The Np is the
alpha
counting
activity on low
A variation mination
is
determined
background
solid-state
N HC1 containing
Th,
i2M HNOS to DDCP [dibutyl
plqnchetting
provides
for
and
sequential
and en~â&#x20AC;&#x2122;ironmental
from EN HC1 to TIOA.
Am, Cm, Bk,
and
counters.
in biological
Pu, Np, and U are extracted
back extracted,
by direct
of the procedure
of actinides
then
Cf,
and
Es are
N, N-diethylcarbamyl
deter-
samples.
The residual extracted
from
phosphonate). The
actinidcs of interest are back-extracted sequentially for quantative
detezminations. P2qmwztion Urine
ofthmpk
collected
in polyethylene
bottles
is
transferred
Erlenmeyer flask with concentrated HNOI (201 n!l of acid Acid is the
added to the
urine
in the
Np, which may be adsorbed
acidified ashed
sample
is evaporated
with HN03 and HzOZ.
polyethylene
on the walls to dryness,
bottle
of the ilnd the
to an per
liter).
to renwe
container. residue
The is wet
Nitrates are metilthesizedto chlorides
by evaporation to prevent interference with Pu (liIj removal.
- J86 -
Reqen ib and Equipment The liquid anion exchanger, TIOA (BrainChemical Co. )
is
diluted to 10 VOI % with xylene and washed with half its volume of O.lN HC1 before use. The alpha-detection equ~pment are 211solid-state counters. The counters arc equipped with detectors ::hathave an active area of 350 mmz and .me capable of accepting l-in. stainless steel planchets. All other reagents used in the procecurc are prepa:redfrom analytical grade chemicals.
Firoccdure 1. Wet ash urine with HN03 and H202; then add 113ml of 8M HC1 to the white salts twice and evaporate the solution to dryness each time. 2.
Dissolve the salts in freshly prepared 8M HC!,- 0.05M NH41 (50ml ofacid/250 ml of urine in sample), andheat to complete solution.
3.
Transfer a 50-ml aliquot of the solution with 25 ml TIOA-xylene into
a separator funnel and shake for 1 min.
of 250 ml or lCSS, rinse
the
flask
twice
with
(For urine samples 10 ml of 8F!HC1,
and add the rinses to the funnel.) 4.
Drain and store the aqueous [lower)
ls)er
for
Pu, Th, #m, Cm,
and Cf analysis. 5.
Rinse the organic phase with 25 ml of EM HC1 - O.OSM NHkI at 80째C and shake for 1 min.
Discard the rinse solution or com-
bine with solution stored for other actinide analysis.
- 187 -
6.
Add 25 ml of 4M HC1
-
0.02M
HF tn
the funnel and shake
vigorously for 10 sec. Drain the Np strip
to
n
iOL1-mI breaker.
Repeat a second time and combine the two 25-ml solutions. Discard
the organic
phase
or strip
with
O.lM IIC1 for uranium
analysis. 7,
Evaporate
the Np strip
to dryness. Wet ash with tLYO1and 1[202.
Rinse sides of breaker with 4M IL%03ond evaporate solution to dryness. 8.
Add
1 ml 4M lINOIand transfer solution to stainless steel
planchcts and evaporate to dryness under an infrared lamp.
Complete transfer with 3 rinses of 4M I{NOJ. 9.
Flame the dried planchet tc dull red, cool, nnd count on lowlCVC1 solid state alpha counters.
10. Calculation: Np activity on planchct is determined as follows:
total count - Bk d dis/(min-planchet)= ~t)(cout=r ~ff ~ . where:
Bkgd. = counter background (3 to 10 counts/24 hr) t
counter cff
= counting time in minutes = counter efficiency (normally0.30)
as a fraction
The sensitivityof this analysis is 0.02 ~ 0.01 dis/[min-samplel. The recovery efficiency is determined by adding a known amount of Np standard to an aliquot of urine sample and followingthe same procedure for analysis.
-
188 -
Procedur? 19.
Detetmlnatlon of “’~:pby W. O. Granade 352
Ganma Ray Spectrometry
Intrcdactiun A gama spectromctric
incthod was develoFed that allows for
the rapid determinationof Np in process solLtions containing fission products. The method is unaffectedky highly salted, corrosive,or organic mcdii3. 237Np is
dctcrninedby ,iymma
spectrometryusing a thin lithium-driftedgermanium [Ge(Li)]semiconductor
detector
to
resolve
the
86.6-keV
237Np gamma ray.
The detector system consists of an Ortcc model 3113-10200, low-energyphoton detector with cooled FIiTprzamp and a resolution of 900-keV full width at half maximum [Fh’HM) ~t 86.&heV. 4096-channelpulse height imaly~er
,!
is used for the accumulation
and storage of the gamma s;)ectra. The data are read onto magnetic tape or printed out directly from a high-spee’jdigital printer. Data reduction is performed using an IBM 360.:iystcm and FORTRAN programs developed to calculate nuclide abundmccs from multichannel gamma ray spectra.: %wcedwe Calibration.
233Pa,
the daughter
of 237Np,
has a 0,017
abundant gamma ray at 86.6-keV that interfereswith the measurement of the 237Np gamma my
of the same encrg}”. 233Pa also has
u 0.34 abundant gamma ray at 311.9-keV that i: not associatedwith a 237Np gamma ray. In order to determine the 233Pa contribution - 189 -
to the 86.6-)ieV237Xp photopeak.
233Pa is purified
233Pa is required. solution
a pure
stancard
by passing
solution
of
an equilibrium
of ‘33Pa-237Npthrot’gha diatomaceoLsearth column which
sorbs 233pan
IIIC
is determined
by alpha
emission). counting
233pa
Aliquots
the ratio
at the 311.9-keV contribution me
cluted,
counting
( 233Pa does not decay by alpha
of counts
of gamma counts
peak.
to the total
level
the ‘:7Np contaminant
and
of 213Pa are pipetted A series
geometry.
determine
is
The ratio counts
into
of the
a standard
233Pa are made to
at the 8tl.6-keV is used to calculate
detected
gamma
peak to counts the
at the 86.6-keV
213Pa peak.
efficiencyof the Gc(Li) detector for 86.G-heV gamma
rays is determinedby calibrationwith known gamma standards between 43.5 and 511.6-kcV. tkaly~i
3
Tnc standards
and sample
arc counted in a holder which ensures
a reproduciblegcomet~ at 2 cm. The deadtime correction (always <20%)
was
found to be accurate to <1%. The gain setting of the
amplifier is adjusted to provide a peak width of 7 to 10 channels (FWUM)to allow reliable integrationof the photopeak area. For a Gaussian distribution,99% of a peak area is contained in 2,1 x Fwllhl.
Therefore a peak area
of 24 channels is used with a gain
setting giving 10 channels FWtB1. The net
counts
per minute of 237Np is calculated by subtracting
from the 86.6-keV the Conqztonbackground and the 23spa contril,ution
- 190 -
total photopeak bmckgromd
is
average
the
of
amm.
The contributia
a~sumed to
be
linear
of
over
from 4 channels
comts
wdcrlying
Co~con
lhc peak area.
An
on each side
of the peak
is used to determine the backgromd correction. For an analysis above less
the
determination
than
101 of
backgrotmd
limit
the
should
(the
measured
relative
value),
be greater
standard
the
peak
area
deviation
■inus
is
the
thanz:
4
50 me
absolute
g-
ray
efficiency
alpha
dis/(min-ml)
ITA.
A standard
phase
andone
shoued
W.
.
1}
Sum 12.5
per minute value of 7’7Np
net
counts
❑inute
per
hy rhc
(photon/disintegration)
of *“N,p results agreed
is
product
and the
that
~ithin
geometry
97% of agreement
in organic
the
by ga-a
An aliquot
5%.
solution
sa~le
the aqueous
of the gs
of detection
obtainsd
237Np standard
from
Close
reliability counted
1
of
detector
at B6.6-keV.
and TTA extraction’
phase.
the
ahmhince
A coqarison
ing
+
disintegration
obtaind by dividing the
{[
I
was =de phase.
of I.Ob x 10s
was cxtractcd from
the
TIM: resulting
237Np had been
extracted
between
the
two mnthods
pulse
height
analysis.
media with no adverse
spcctromctfi
uffects.
lTA
using [organic]
gama
into
comt-
the
demonstrated
Samples
lTA the
can be
A lower
limit
of 1 x 10” d/m/ml at a confidence level of 9S1 was
detemined fmm a series
of counts
using
solution.
-
191 -
a diluted
standard
237Sp
F?u,%?rw?lm
-.*
!4. A. Itakat
and E. K. mkcs,
Cwm. +, 109
c’. .%d~J@H@t.
[1970).
.;.
*.
F.
L.”mcr r:.
Ilidcr.
Scieeai
IEAEC Rqort
P?tiodr
tii~:icul KAPL-890
-
192
( 19S3).
-
for
Fwws I%vmea
Procedure 20C
Spectrophotometric
of Np
Determqillation
R. G. Bryan and G. R. Watw’bury302 Outline
of Method
Np is measured complex
after
as the
spectrophotometricall!r
separation
from Pu and impul-ity
arsenazo
elements
Ill
by liquid-
liquid extraction. U is removed first by extraction from 4M HC1 into triisooctyl amine (lIOA)-carbon tetr:~chloride,while Np(IV) and Pu(III) are stabilized in their
nonexl:ractable
oxidation
states tJyFe(II] and ascorbic acid. Then Sp(IV) from 8MHC1 into
TIOA
and
back-extracted
?ip.arsenazo
111 complex is formed
is measured
at a wavelength
of
O.lM I{Cl.
into
in 6.lM I!Cl,
665
is extracted
and the
The absorbance
nm.
.7eag%~t8 o
Arsenazo
111, 0.2$
acid-2, 7-his of arsenazo o
(azo-2) -phenylarsonLc 111 in S00 ml of wate::
acid,
Ascorbic
[~,8-dihydrox:plapthal,ene
Dissolve
5$.
120ml
of 8t4W1.
c
Carbon
tatrachloride,
o
I!Cl,
o
Np stock
●
Phosphoric
●
KOH, pellets,
12M, reagent
(CClk)
acid].
6-disulfonic
Dissolve
containing
two KOHpellets.
6 gr:~ms of ascorbic
reaglmt
1 g
acid in
grade.
grade.
Dissolve
solution.
acid,
-3,
higlh purity
(HJPO*) 1S.9}1, rzagent
reagent
grade.
- 193 -
Np metal
grade.
in
12M HC1.
Reducing
●
5% ascorbic
solution,
Dissolve
ion in 4M HC1.
and 0.5% Fe(II]
2.5 It of ascorbic
acid
and
in 50 ml of 4hl I{Cl.
1.75 g of Fe(NH2S03)z Tri(iso-octyl)amine-xylenc
●
acid
(TIOA in xylene), 5%.
Dissolve 31 ml of TIOA in 500 ml of re~gent-grade
xylene.
Tri(iso-octyl)amine-carbontetrachloride (TIOA-CClb),
●
5%.
Dissolve
31 ml of TIOA ir 500 ml of CC14.
Equipment ●
Extractors
(see
●
Laboratory
glassware
volumetric
flasks).
●
figure
(beakers,
302).
pipet.s,
syringes,
and
Beckman model DU or equivalent,
Spectrophotometer, ❑atched
in Reference
fused-silica
cells
having
l-cm
light
with
paths.
Pretreatment The sample material
is
chlorofom.
of metal
or alloy
Cutting
remved. For each
oil
Pu ❑etal
Np.
solution
containing
blank
Make
duplicate a known
inspected,
and extraneous
is remwed by washing with methyl
sample,
portions, each not greater than 60 ~g of
is
200
take
mg and
determinations quantity
solution.
- 194 -
of
Np,
two accurately containing
less
on each
sample,
and on the
weighed than
reagent
on a
Procedure 1.
Place
each accurately
weighed
2,
reducing
Prepare
blank
reagent
Prepare
Np solution
approximately
solutions
expected
to 5 ml with
the
Repeat
7.
Add 5 â?&#x2018;l of
Steps
taining
Pu.
phases
the
phases
HC1,
phases
of
mix
the
the
to separate inside
for
Remove the
layer
1 min.
inside
Wash the
Dilute
prepared
2 rein,
and then
1 min.
and discard.
12M HC1 and 10 ml of TIOA-xylene
for
acid-al
and
4 and 5.
to separate
Wash the
for
solutions
for
phases
to separate
â?&#x2018;ix the
extractor,
sample
4M WI.
mix the
TIOA-CCl~
Np
to each of two extractors.
solution
the phases
of of
in the
steps,
6.
10.
to that
an amunt
in previous
Separate
9.
contains
TIOA-CCl~ to each of the
5.
1 ml of reduc-
an aliquot
Add 5 ml of
allow
8.
by adding
by adding
that
equal
1 ml of reducing
4.
has dissolved,
and 2.5 ml of water.
solutions
known Np solutions
standard
the
solution
sample
extractor
and 4 ml of 4M HC1 to each of two extractors.
ing solution 3.
in a glass
Mhen the
and add 1.5 ml of 12M I{Cl. add 1 ml of the
sample
Remove
extractor
phases
for of the
2 rein,
for
1 min. extractor
and allow
aqueous
for
to each
3 min and allo~ the
aqueous
phases
the
phase
con-
wit~h 53 ascorbic
2 min. and allow
the
Rcmnm
with
aqueous
RV IIC1.
to separlatc
the
for
phase.
Mix the
1 min.
phase.
Add
4 ml of O.lM HC1 to each extractor. Mix the phases
for
3 tin,
and
allow
to
separate
- 195 -
for
1 min.
11.
Remove
aqueous
the
Repeat
13.
Add ~.5 ml of 0.23
Steps
flask, the
flask
10 and 11. Ar~ena~~
contents
of the
the
l-cm light
at
(As-Ah)
‘p’
~o]ution
of the
Stopper
solution
a wavelength
vol~tric and mix
in cells
of
66S
having
nm.
LIE ofN@
(Wk,
‘pm = (Ak-Ab)
water.
to the
f’dsk.
absorbance paths
III
to 25 ❑l with
and dilute
Measure
15,
a 25-ml volumetric
I{Cl,and 12.7 ml of 12N HC1.
1~,
14.
into
0.6 ml of H3POb, 1 ml of 5% ascorbic acid-
containing ~
phase
(sqle
wt in grama
Ab = absorbance
of blank
Ak = absorbance
of known Np solution
As = ahsorbancc
of unknan
saqIlc
Wk = ug of Np in known NF solution Uclative measuring tested
only
deviations
range
between
Pd,
Th,
present
U,
and Zr
cause
in concentrations
serious
greater
significantly
conplcxcs
extracted
than
0.8%.
and IINOI cause low results method *’aPu
from HC; solution.
up to 1 mg of Zr without
tolerates as Iargc
the
intense
unless
affecting remved
radioactiqrity
as 100 mg.
- 196 -
Of
45 elements
interference,
initial extraction from 4N }ICIinto TIOA remves is not
and 1.1S in
7.2
8.S to 330 ppm of Np in 200 mg samples.
only
if
standard
the
but
However,
some U, and Th Also,
lilPOh
analysis.
HF The
by volatilization. fxom
quantities
of
Procedure 21.
Outline Np(IV]
Microvolumetrfc with EDTA
Complexonetrlc Method for Np
A. P,
Smirnov-Averin,
N.
Ermoloev,
P.
G. and
N.
S.
N,
Kovalenko,
Krot:â&#x20AC;&#x2122;26
of Method is
titrated with a solution of EDTA at pH 1.3 to 2.0
with xylenol orange as indicator. The ;?eacticmc)fNp(IV) with EDTA is stoichiometric, and the color changes from bright rose to light yellow at equal molar concent:riltions.The determination takes approximately two hours; the erro:-is tC1.03mg.
Reagenti
and Equipmnr
o
Hcl, reagent grade
o
Test solution, 10 mg Mn2+ and ,50mg NH20H*MC1 per ml
e
30(%KOH
a
10% NaCl in
s
0.:1%xylenol orange
@
Centrifuge tubes
@
Micro or semimicroburet
4M
HC1
Pswcedwe 1.
Add
1 to
4 ml of
Np solution
and
2 ml of test solution
containing 10 mg Mn2+ and !50mg of Ni120H*HClper ml into a centrifuge tube. 2.
Dilute to 6 to 8 ml, and heat to 60°C; add 30% KOH with mixing until the pti>10.
3,
Centrifuge the precipitate, and discard the solution.
4,
Add 10% NaCl in 4M HC1 dropwise until the precipitate is dissolved. - 197 -
5.
1.S ml of 4M HC1 COnta:Lning 50 ❑g of NIIZOH”HC1
Add 1 to
per ml, water 6.
7.
and heat
the
solution
for
20 min on a boiling
bath.
Cool the
solution,
dilute
towldO
ml with
water,
and add
1 to 2 drops
of 0.1% xylenol or.mge.
Titrate
2 x lLI-lM EI.)TAfrom a microburet until the
with
color
changes
from rose
brig~t
to
yellw..
lio tes 1,
[ICI solutions are preferred in xder Np to the acid
tetravalent
state
with
is not suitable,
since
its
interfere 2.
do not
decomposition
products
interfere
with
the
(Mn2+, Ni2”, titration,
are
as carriers.
Np can bc determined presence rare
the
NI[2011”IIC1. Ascorbic
Doubly charged readily hydrolyzable ions used
all
with the titration.
U3Z2+), which
3.
to reduce
of
earths
large
(3{@0-, to Pu(III)
of alkali,
Mn2*, Zn2+, base
C@42-,
and does not
and Fe3+ interfere
of tO.03
Anions
precipitation Cr2072-, interfere
because
- 198 -
they
mg in the
alkaline Cd2+,
C02+ and lM322+.
by strong SOk2-,
an error
amounts
elements,
to 20 mg), Ni2+, separated
with
Pb2+, which include
and EMA’-. up to 2 mg. arc
cotitrated
earth,
and
Cr3+ (up are
NO]-, Pu is
reduced
2rh+,
fib+,
with
Np(lV).
Procedure 22.
Photanetrlc Determination of Canplex
lip
Yu. P. Novikov, S. A. Ivanova, and A. A. Nemodruk3s3 Outline
molar
E.
V.
Peroxide
Bezrogova,
of Method
Np(V) forms (pH >8) .
as the
an intensely
The ratio
ofNp(V)
absorptivities
and 7950 t350,
colored
complex
to Hz02 in the
of the
complex
at
complex
is
solutions 1:1; the
430 and 370 nm are
The method
respectively.
in alkaline
is highly
5010 t210
selective
for Np.
t?eagentaand Eq? - :ent grade
.
NaOtl,
â&#x2014;?
11202, CP grade
â&#x2014;?
Spectrophotometer
Cl)
and cells.
Pzwcedurw 1.
Add the
dilute
acid
%2.5 ml containing 7 A.
Adjust
(HN03, HCl, or IIC1(14) solution, 5 to 50 Ug of Np into
to Np(V) by adding
in a boiling 3.
Cool the
4.
Neutralize
~atcr
bath
solution,
0.1 for
a test
tube.
ml of 30% 11Z02, and keep
10 min.
and add 0.1
to pl{ 1 to 3 with
ml of 0..5}1 IIzOZ.
NaOi,
add an extra
nd
1 ml
of 4N NaOH. 5.
Dilute
6.
Measure
to exactly
realtive 7,
Detenninc
the
4 ml with
absorbance
water,
and mix thoroughly.
in a 1 cm cell
iit
430 or 370 nm
to a blank. the
Np content
using
- 199 -
a calibration
curve,
Note8
1.
Np(V),
but not Np(IV)
or N:J(VI),
gives
a color
reaction
with 11:02. 2.
The stability increases the
3.
as the pH is
absorbance the
change
?l~sorbance.
the
time
for
constant
unchanged
for
two hours.
to >? x 10-3M does
At higher absorbance
increases.
reduce Fluoride complex.
absorbance reduces
of the the
Tartrate,
Np(V)
carbonate,
and is removed
of the
is present, Four-fold
interfere.
-
200
-
of the
phosphate
Np(V) peroxide
and sulfate
by centrifugation,
interfere.
amounts
(lUi~)zHPOk
complex.
absorbance
When iron
have no effect.
of Fe do not
Greatm
NaOH.
not
H202 concentrations,
When the solution contains U, 7 â&#x20AC;&#x153;to 10 mg of
the
complex
In O.lM NaOl{ solution,
HZOZ concentratio~
is added before
s.
Np(li) peroxide
increased.
rem~ins
Increasing the
4.
of th(? colored
ions
to O.lM
Fe(OH).q precipitates
Up to 300-fold amounts
amounts
of Pu do not
procedure
23.
Separation Impurities J.
Outline
dilute and
sulfamic
Analysis
on strong
The residue state
of
by the
anion
anionic
resin;
the
The cycle
resin.
and baked cationic
is
HN03, and the
is dissolved
adjustment
The hexanitrato base
HC1, and the
in concentrated
to dryness.
acid.
are evaporated 6M
are dissolved
is heated
sorbed
Spectrographic
ofllethod
HN09, and Np oxidation
sorbed not
Np for
Uheat232
A.
Np mmpounds solution
of
in
is made with
NzH4
cornplcx of Np(IV)
is
c~tionic
impurities
are
rspeated,
and the
effluents
at 4110°C.
The residue
impurities
are
determned
is dissolved
in
by emission
spectroscopy. Reagente
and Equipment
●
Double-distilled
HNOg
●
“Dowex” 1-4 100 mesh
●
Hydrazine
●
Sulfamic
●
Cobalt
●
Small
●
Spectrograph
(N2H~] acid
solution glass
column
Pxx%?dure 1.
Dissolve evaporate
2.
Dissolve fourth least
SO mg of sample
in concentrated
HN03, and
to dryness. solid
residue
in 2 ml of 0.35M HN03 and add one-
ml of llM aqueous 30 min for
valance
- 201
solut.,on adj’x-:ment.
-
of N2H@. Wait at
3.
4.
ml of
Add one-half
3M sulfamic
HN03, and mix the
solution.
Pass
solution
the
adjusted
“Dowex” l-X4
resin
acid
thrwgh
,and 2.5 ml of 16M
a 3 ml bed of ILd-mesh
at <3 ml/(min-cm2j,
and collect
the
effluent. 5.
6.
Hash the
resin
effluent
with
Elute
the 7.
Evaporate
w1O ml of from Step
the
coluam with
rermved
resin
8M HNOs for
Steps
with
Evaporate
the
Dissolve
N llN03, and combine
0.35M N3,
two cycles sorption
and condition
re~se.
and wasl
2 through
the
2.
with
the sorption
to dryness 9.
that
Np from
and repeat
8.
with
effluents
to dryness,
6.
(99.96% of the
of anim
exchange].
and wasl
effluents
Np was
from Step
7
and bake at 400°C t~ expel hydrazine. the
residue
in 1 ml of
aqua regia,
and evaporate
to dryness. 10.
Dissolved
the
last
residue
in
1 ml of 6M HCI cont~ining
serves
as
m internal
standard.
solution
to dryness
100 ug of Co, which 11.
Evaporate
two hundred
Bg of ths
top of a l/4-inch-diameter 12.
Excite
the
large
Littrow
wavelength step
sample
of the
is
blank
distilled
tlNOJ was used.
should
using
a
the 2500 to 3S00 A width
100%/3S% i;
is
inserted
10 Urn, and a twoin the
slit.
used.
relatively
a reagent
in
The slit
filter
neutral
electrode.
30 sec b? a 10-amp dc arc
spectrograph
region.
SA-2 emulsion Because
for
flat-top
on
large
be carried
-
volume of reagents
throu,~h
202
-
the procedure.
used, Doubly
Recovery
was 88 to 106% for
all
elements
except Ni which was
65%. The coefficient the several 17%.
elements
The precision
inco~lete
of variation
remval
varies
The method was applied Al,
from 9 to 24% with
is affected of cationic
for a single
by large
andMg.
- 203 -
an average
volumes
iupuritics
to determination
determination
Fe,
Cr,
of
of reagents
from the of
of
resin
and
column.
Ni, Mn, Cu,
Procedure 24.
Photometric Determination of Np as the Xylenol Orange Complex
P.
N. and
orange
J.
reacts
S.
t(ovalenko,
N.
N.
Krot,
in weakly acidic solution (pH %2) with
to form a color
complex with
nm and molar extinction is three times
more sensitive
of xylenol
is the relatively
an absorbance
coefficient than
thorin
orange
minor
coupared
interference
but
only
for Np[lV). to thorin
xylenol
maximum at 550
of 5.5 x 10b.
111 as a reagent
sensitive as Arsenazo advantage
G.
Blokhin30n
of Metiwd
Outline Np(IV)
Ermoloev,
V.
Xylenol
orange
one-half
as
The greatest
and Arsena:o
111
of U.
Ff&aLJect8 Umi Qaipme):t tlc1 30”.
~al
Test
solution,
10 q
M112’ and 50 mg of XIIZOII”IIC1pcr ml
100 ❑g Sll@H”llCl per ❑l in 7S1IK1 31 xm~ai 0.0S3
xylcnol
orange
pll 3wtcr Spcctrophoto=tcr Centrifuge
1.
M
solution
tube, @ :.
tdms
containing
and dilute
to
S to
20 us of
S to 8 ●l;
then
Sp to a centrifuge
mdd S0% S3Wuncil
>10.
Add 1 ml of 50 mK of
test
solution
.SHZCMI-IKI
ine=
-m4-
contrnlnlnr the
ccntrihl:c
10 mg of C*C.
$hlJ*
and
3.
and centrifuge
Mix
then dissolve ing 4.
25 5.
the
boiling
on a water
bath
for
Np[IV).
solution
and measure
cells
ml.
to almst
and dilute
FE’K-M
liquid;
1 ml of 0.05%
orange, and adjust to #l 2.0 to 2.2 with 2NI.Nl@ll.
Transfer
Mix
the
in 2 ml c’f 7M HC1 contain-
to %15 ml with water, add exactl,y
Dilute
flask, 7.
solution
min to obtain
xylenol 6.
the precipitate
100 mg NHzOtl”tlCl per
Heat the
Discard
the precipitate.
to vol-e the
Instrument
sith
quantitatively
a path
with water.
optical
density
with
fitted
to a 2S ml volmetric
a
of
green
of 5 cm at 550 nm.
solution is the sam
the
filter
solution
m
an
and using
The reference
plland reagtnt coqositictn as the
Sp solution. ;1012?8 1.
the SF concentration cali~ration
* -.
The
is detcrminrd
from a standard
cume.
wq~ircs ‘-3
determination
hours,
and the error
usually
{s <slug. 3.
~p
c=
be detcmined
by the abovr
method
llCZlllOIo and NzSOb solutions
an9J also
containing
arm remowd
base
other
precipitation:
anions
that
flmride
-ms-
in IKI,
IMI,
I,a solutions
and phosphate
by the
strong
interfere.
Procedure
25.
Analysis
Np by Controlled Potential Coulanetry
for
R. W. Stro.matt’”
Intrv&ctwn Controlled little
potential
of Np, and
as 2 ug
general
The
deviation.
coulmetry
to Np[VI) with
procedure
Ce(IV),
electrolytically
7 vg can
then
reduced
is coulo-trically
is
is to first
to Np(VI)
detecting
with
and excess
all
Ce(IV) Finally
to determine
as
6% standard
oxidize
and Ce(l II).
Np(V)
oxidized
for
be dett’nnined
the Np(VI)
to
useful
the are the
the
Np
Np(V)
concentration
of Np. RmgeRta
and ~uipment
●
lM H2S04
●
Mercury
●
Mercuric
●
Pure
Q
Sodium silicate
●
Controlled
●
Titration
metal sulfate
heli=
gas solution
potential cell
coulo~ter
(working
electrode
electrode
Pt wirt
Pt gauze,
isolated
and saturated
calomel
reference)
Plvra2df4n2
1.
Add the
Np sample
and adjust
the
Add Ce(lV)
co~le
medium into
the
cell,
ion and sulfate ion concentrations the
is affected
solution
by a persistent
titration
ion concer,t~tion
to 2N but
0.4
Np(V/VI) 2.
hydrogen
(The hydrogen
to %lN. between
and the
until
color. -206-
electrc,de by the there
is
potential sulfate
is an excess
not
critical of the
concentration). as evidenced
De-aerate
the
solution
this
the
excess
3.
time
with
He for
Cc(IV)
has
[If
5 min.
rc.~ctcd,
during
add additional
Ce(IV)]. 4.
Apply the potential to reduce Ce[IV)
Np(V) and Cc(Ill)
to
the
\p(v1)
until
and
cxccss
chc current
bccomcs
constant. 5.
Apply the potential The oxidation
is continued Make several
obtained. current,
a blank
Ce(IV),
and after
and oxidation
a constant
readings the
solution
of the
integrated
current
is
intcgrat~’d :urrent
containing
titrations
at the
the Np titration.
and extrapolate
the
S min of de-aeration
for oxidation, read
7.
until
and extrapolate
Prepare
for
the Np(V) to Np(VI).
curve
to
time.
zero
6.
to oxidize
same amount of perform
reduction
same potentials
as used
After constant current is rcachcd
the
to zero
current several times
integrate
time.
Subtract the zero-time integrated current of the hliinti from of
that
Np
based
the
the
cell
instrument
Np lost
are
ar.d calculztc
Np titration,
on the the
accuracy, in
for
taken
in into
(l”or
calibration.
the
de-mration
tlm mount
and
Illg!lcst
from
migration
account.)
Noh?a 1.
The ,Np(V]/[YI] reversibly
can be titr;lted
quantitatit-cly
in 10101, IIC106, and 112!;Ob; hcnicrcrp
reproducible potentials
couple
arc obtmincd
results of
separated better
the
in ll@~.
207
112SO~.
anlJ Sp(Vj/(\l)
Pu(III)/(I\’)
-
with
-
and
more
Also, the COIIIIICS arc
2.
Ce(IV]
ion
is used
?Jp is
rapid
for
oxidation
because
and quantitative,
oxidation
of
and Pu(IV) is not oxidized
significantly in H2SOk. 3.
Coulornetric
titrations
in solutions
containing
organic
contaminants are often slow and yield low values. 4.
The concentration states
of Np in the
can be made using
the
different
Pt electrode
ANP(J’1/(VI) couple Cm be titrat~!d from oxidation of Np(IV). Np(VI)
is
The Np(V) is
determined then
initially ❑ined
s.
these
present.
two titrations
between
plus
total
and the
Propst 31’ has utilizing
reported
a conducting
The
interference reduction is
and Np(lV) the
to Np(V).
and the the Np(V)
Np concentration
discussed,
from the difference Np(VI)
without
coulcmetrically,
The total
as previously
cell.
by coulometric
oxidized
difference between
oxidation
is
is detercalculated
concentrations
of Np(V)
Np.
a coulometric
method
for
Np
glass ele:trode in a thin-layer
electrochemical CC1l. Organic conta.mirlants interfered and were remved
by a bisulfate
- 208
-
fusion
procedure.
REFERENCES
1.
E. McMillan
2.
J. W. Kennedy, Hzya. Rev. 70,
3. 4.
and P. H. Abelson,
Phy8.
B.
37,
1185 (1940).
G. T. Seaborg, E. Segre”, and A. C. Wahl, 555
(1946).
A. C. Wahl and G. T. Seaborg, L.
Rev.
Phys.
Rev.
73, 940 (194S).
Magnusson and T. J. LaChapelle, J. .Amer. Chem. SCC. 70,
3534 (1948).
s.
W. W. Schulz and G. E. Benedict, Reavervj, USAEC Report TID-25995
Neptuniun
6.
D. F. Peppard, G. W. Mason, P. R. Cray, J. AmerB.Chem. Sot. 74, 6081 (1952).
7.
W. A. Myers and M. Lindner, (1971).
8.
of the Tronsumnikn C. Keller, The ChemiBtq Chemie, Genmny [1971). pp. 253-332,Verlag
9.
V. A. Mikhailov, pp 1-10, Halsted
J.
Production
and
(1972).
Inorg.
and J. F. Mech, Nucl.
Chem,, 33,
3233
Elemente,
Anai!gtical Chemistry of Neptunium, Press, New York (1973).
10.
C. M. Lederer, J. M. Hollander, I. Perlman, Tabza of the Isotopes, 6th Edition, John Wiley, New York (1968).
11.
S. Fried
and N. Davidson,
12. E. F. Westmm, 3399
Jr.
J.
Amer.
and L. Eyring,
Chem. SGC. 70,
3539 (1948).
i“. Amer. L7nem. Sm.
73,
(1951).
13.
ant, J. A. Leary, Preparation A. N. Morgan, K. W. R. Johnson, of A@tuni~237 hktal. USAEC Repcrt LAMS-2756 (1962).
14.
H. A. C. McKay, J. S. Naim , and M. B. Waldron, International Pwoeedinge of the Seoond Lhited IUc:tions Confe~m on the Peax?ful Uaee of Atomic BMW, 28, 2nd Geneva, 1304 (19S8).
15.
D. L. Baaso, U. V. Conner, and D. A. Burton, Production of USAEC Report Neptwnim &ta2 on a 100 b 400 Gram Soale. MT- 1032 (1967] .
-209
-
16. J. A. Lee, P. G. Mardon, J. H. Pear:e, anclR. O. A. Hall, J. phlj8.Chem. SoZid~ 11, 177 (19591. Zachariasen,
Acts
Cryst.
5, 660
(19!;2).
17.
W. li.
18.
L. J. Wittenberg, G. A. Vaughn, and R. DeWitt, in: Plutonium 1!?70 and other Actinide8, Proceeding cf the 4th Intemationa2 Conference on Phaanium and Other Actinides (W. N. Miner, ed) 1970, [?JucZ. Meti:ZZurgy 17, 659 [1970)].
1!3.
H. A. Eick and R. N. R. Mulford, J. Chem. Phg8. (1964).
20.
D.
21.
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1!51
S. 60 Wrray,
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U. Meinke,
tbrset
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293
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B.
Id.
~.
Ckw.
KR-$S
W-SOSl
I
W&L- lJ~SB 0$ ’-$86
&w@.
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(196SjI.
[I$MJ).
V.
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U. N. Chgutova, 0. M. Petruhhin Nhk. 28, SS8 (1%3) Zh,, Ana2it. L.
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16:1. l{.tittc,,A. Naturforuah. 16:! .
c,
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J.
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A.
@qIIort
*-S~6
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l#AEC
lk?k~.
1?9.
u. w. tisyakwo C. S. Gwwyw, 89M9 G. S1 Yakowlew,a%qaratim of Trmsuraahm ?boaphorlc
Arpwae not
Elcwnts
by SOlutkn Ex!:ractfowi in Alky] ●t Transolutoniun S~sitm, (Proc98din@ La&mtory, May 196S.
Acids, ” Pqter
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Gray,
White ●nd U. J.
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Jr. , and J.
Ross,
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J.
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189,,
D. E. Homer
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-
K.
W. J.
And.
Maeck. Cbl.
-
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Ft~rK
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Booman,
334 177s
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Kussy,
and J.
.
E.
Rein,
(1%1).
199.
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%ooedurea,
!5iwannah River
ENI)
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