Global journal 47

www.globaljournal.asia GJESR RESEARCH PAPER VOL. 1 [ISSUE 12] JANUARY, 2015

ISSN:- 2349–283X

Utilization of Red Mud using Fly Ash for Ground Improvement 1Prabha

Kant Pandey Post Graduate Student Department of Civil Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur(UP), India Email: pra7237@gmail.com

2Dr.

S.M. Ali Jawaid Associate Professor Department of Civil Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur(UP), India Email: smaj@rediffmail.com

ABSTRACT: This paper illustrates the possibility of utilization of the Red Mud waste generated from HINDALCO (Hindustan Aluminium Company) at Renukoot, Shonbhadra (U.P.) and also utilizing Fly Ash generated from the coal/lignite based thermal power plants through ground improvement technique, leading to an effective waste management. In this study samples were prepared by mixing different percentage of Red Mud with different percentage of soil, with an aim to compare strength gain with Fly Ash. Red Mud mixed with highly compressible soil and reinforced with Fly Ash may find potential applications in road and embankment constructions with due regards for its strength characteristics, durability, longevity and environmental safety.

Keywords: Generation; Utilization; Environmental safety.

1. INTRODUCTION

performance of Red Mud, Red Mud-soil and Red Mud-soil-Fly ash fills. The maximum dry density (MDD) and optimum moisture content (OMC) obtained by Proctor compaction test becomes the benchmark for determining the quality of compaction. The dry density of fill is of primary importance, as it is the major parameter of strength and compressibility of the fills.

Red Mud is produced during the process for alumina production. Depending on the raw material processed, 1–2.5 tons of red mud is generated per ton of alumina produced. In India, about 4.71million tons/annum of red mud is produced which is 6.25% of world’s total generation. It is the insoluble product after bauxite digestion with sodium hydroxide at elevated temperature and pressure. It is a mixture of compounds originally present in the parent mineral bauxite and of compounds formed or introduced during the Bayer cycle. It is disposed as slurry having a solid concentration in the range of 10-30%, pH in the range of 10-13 and high ionic strength.

a) Red Mud

The aim of the work is to stabilize the waste (Red Mud) obtained from alumina plant by mixing it with soil and fly ash obtained from thermal power plant, which can subsequently be utilized for various geotechnical and highway engineering applications such as filling of embankments, construction of highways, replacement of poor subgrade soil etc.

This sample of Red Mud has been obtained from HINDALCO, Renukoot (U.P.). This Red mud is the solid waste residue of the digestion of bauxite ores with caustic soda for alumina (Al2O3) production. It is a mixture of compounds originally present in the parent mineral bauxite and of compounds formed or introduced during the Bayer cycle.

1. MATERIALS USED a.

Red Mud

b.

Soil

c.

Fly Ash

The performance of stabilized mixes depends upon the compaction or densification of the fill, proper compaction is therefore, critical to the

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 12] JANUARY, 2015

ISSN:- 2349–283X

Geotechnical engineering properties of the Red Mud

Fig.1 Red Mud Sample from HINDALCO Plant, Renukoot, (U.P.)

Grain Size Distribution Curve for Red Mud

Fig.2 Grain size distribution curve Proctor compaction test of Red Mud

Fig.3 OMC curve of Red Mud

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 12] JANUARY, 2015

b)

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SOIL

The soil sample which was collected from Ravindra Nagar (Dhoos) Kushinagar. The engineering properties, proctor’s compaction test and grain size distribution curve of the soil aregiven: Geotechnical Engineering Properties of Soil

Fig.5 Grain size curve for soil c)

Proctor’s Compaction Test of Soil

Fig.4 Compaction test curve for soil Grain Size Distribution Curve of Soil

Fly Ash

The fly ash used in the study was brought from Tanda Thermal Power Station situated at Ambedkar Nagar in Uttar Pradesh, which was available free of cost. Fly Ash is classified as silt of low compressibility. Fly Ash from Electrostatic Precipitator (ESP) is continuously removed to buffer hopers located near ESP by means of vacuum pumps. From buffer hoppers, dry fly ash is conveyed to storage silos, from there it can be unloaded dry to pneumatic tank trucks or conditioned with water by hydro mix dust conditioners for discharge to open bed trucks, Ash to be stored is removed by belt conveyers to ash storage area. Bottom ash is continuously collected in wet hoppers, ground to sand size and periodically transferred to one of six hydro bins for decanting.

For the present investigation, dry fly ash from hopper is collected in polythene bags. Fly Ash can be collected into different categories such as dry fly ash, bottom fly ah, conditioned fly ash.

Dry fly ash can be collected from different rows of electrostatic precipitators. Bottom ash is collected from bottom of the boiler. Conditioned fly ash is also available in ash mound for use in landfills and ash building products.

Two classes of fly Ash are defined by ASTM C618: Class F Fly Ash and Class C Fly Ash. The main difference between these classes is the

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 12] JANUARY, 2015

amount of calcium, silica, alumina, and iron content in the ash. The chemical property of the fly ash is highly influenced by the chemical content of the coal burned. (i.e., anthracite, bituminous, lignite).The free lime content of fly ash contribute to self- hardening, fraction of lime, present as free lime in the form of calcium oxide or calcium hydroxide, controls selfhardening characteristics of fly ashes.

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and the Geotechnical properties proportion are shown in Table 4.

of

mix

Geotechnical Engineering Properties of Fly Ash

On the basis of past research (Sharif, 2012) we found that 3% Fly Ash mixing gives the best result in soil stabilization therefore we mix 3% Fly Ash in different percentage of soil and Red Mud. 5 RESULTS AND DISCUSSION 5.1 Stabilization of Red Mud

Proctor compaction test of Fly Ash

Different percentage at which Red Mud was mixed with soil and its OMC and CBR is given in Table 5. From the table and graph it is clear that strength of the mixture is maximum when 30% Red Mud and 3% is Fly Ash added to the 67 % of soil.

Table 5 Variation of OMC%, MDD and CBR% with Red Mud Content

Fig.6 Compaction test curve for Fly Ash 1.

Mix Preparations for Stabilization of Red Mud

The Red Mud is mixed with highly compressible soil and fly ash in different proportion, thereafter, best mix has been found on the basis of Optimum Moisture content and California bearing ratio test and then to the best mix has been selected to improve the properties of soil.

The following proportions of mix were prepared

From the above table it is also observed that the CBR Value for the 11q3 Fly Ash is less than CBR value of Red Mud, and Dry density value of Red Mud is higher than Dry density value of the soil.

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 12] JANUARY, 2015

Thus these results also shown an indication that Red Mud can be a best material for Geotechnical purposes and even in Road construction works.

ISSN:- 2349–283X

In order to compare the result obtained when 30% Red Mud, 67% soil and 3% Fly Ash is mixed maximum CBR of 7.354% is found and after this when the percentage of Red Mud is increased the CBR value decreases.

2. Conclusions

Fig 7 Result of Red Mud mixture % and MDD As evident from fig 7, on increase the percentage of Red Mud in the mixture of soil and Fly Ash, leads to increases in dry density because Red Mud is heavy weight compared to soil and the particles present in the Red Mud are finer than soil.

With the aim to utilize the Aluminium Plant industrial waste such as Red Mud from HINDALCO Pvt. Ltd., Renukoot, Uttar Pradesh for Utilization as stabilized Material in Road construction and other engineering application.

Based on the experimental study, it is found that Red Mud waste may be utilized well in soil stabilization and other Geotechnical Engineering projects by mixing Red Mud with Soil and Fly ash. Thus this method of utilization may resolve major environmental problem of Disposal of Red Mud waste Obtained from Aluminium companies.

Based on this experimental study, the following conclusion may be drawn:  Specific gravity of the red mud is 2.85 which is very high compared to the soil solids. So the density of red mud will be more and so the strength is more.

Fig 8 Result of Red Mud mixture% and OMC As shown figure 8, it is observed that the Optimum moisture Content of the Red Mud increases on increasing the percentage of Red Mud in the mixture of soil and Fly Ash, because surface area of the sample increases.

 From the graph showing particle size distribution mud indicated grains are fine and it is well graded. So the soil can be used as an embankment material, backfill material etc.  The maximum dry density and optimum moisture content of the red mud is 1.712gm/cc and 30.5% respectively.  Co-efficient of permeability of red mud is 5.786×10-7cm/s which shows that permeability is very low. Low permeable materials can be used for construction of earthen dams, road embankments etc.  The cohesive strength and the angle of shear resistance obtained from the triaxial test are 0.125 kg/cm2 and 25.800.

The strength value of the red mud is higher than the conventional clay material.

Fig.9 Result of Fly-ash mixture% and CBR

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 CBR value of the red mud is 3.368% which is greater than the 3%, so we can use the red mud as a road material in village side.  When this Red Mud is used with Fly Ash and Soil its CBR value increases to 7.354 %, thus this being a good material for Road sub grade material and soil is well stabilized.  By seeing all these properties of the red mud we can utilize the red as geotechnical material like Backfill material, road sub-grade material embankment material. Red mud is further stabilized to enhance the more strength with lime, gypsum, etc.

3. Refrences 1. Beeghly, J. H. (2003). “Recent experiences with lime-fly ash stabilization of pavement subgrade soils, base, and recycled asphalt.”

Proceedings of International Ash Utilization Symposium, 2003, Lexington, Ky., 0-967 4971–5–9, 435– 452.

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4. R. K. Paramguru, P. C. Rath, and V. N. Misra, (2005) “Trends in red mud utilization - a review,” Mineral Processing & Extractive Metallurgy Review, vol. 26, no. 1, pp. 1–29.

5. Cablik V. (2007). Characterization and applications of red mud from bauxite processing.

(Mineral Resource Management) ;23 (4): 29-38.

6. Sun YF, Dong FZ, Liu JT. (2009).

Technology for recovering iron from red mud by Bayer process (In Chinese).

Met. Mine. ; (9):176–178.

7. U. V. Parlikar, P. K. Saka, and S. A. Khadilkar, (2011) “Technological options for effective utilization of bauxite residue (Red mud) — a review,” in International Seminar on Bauxite Residue (RED MUD), Goa, India.

8. E. Balomenos, I. Gianopoulou, D. Panias, I. Paspaliaris (2011) “A Novel Red Mud Treatment Process : Process design and preliminary results” TRAVAUX Vol. 36 No. 40.

2. Gray D.H. & Lin Y.K. (1972). Engineering Properties of Compacted Fly Ash. Jl. of SMFE, Proc. ASCE, 98, 361-380.

9. Qiu XR, Qi YY. (2011). Reasonable utilization of red mud in the cement industry. Cem. Technol. (6):103–105.

3. Kaniraj, S. R., and Havanagi, V. G. (1999). “Geotechnical characteristics of fly ash-soil mixtures.” Geotechnical Engineering, 30 (2), 129–147.

10. Sharif (2012). “Flyash mixed with waste sludge and reinforced with geofiber ” A.M.U.,Aligarh.

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