Physics of Novel System Hydrodynamics

NO TITLE LEADER & KEY PERSONNEL PROJECT SUMMARIES

P1.2 Coarse Particle Separations (continued)

16 Density separation using the Sink-Hole Fluidiser Leader:

L/Prof Kevin Galvin (UON)

Key Personnel:

Prof Chris Aldrich (Curtin)

PhD Student:

Mitchell Craig (Curtin)

FLSmidth

This project, which is related to P17, aims to understand the fluidisation of particulate systems in a in a novel, Centre-developed technology, The Sink-Hole Fluidiser. The device utilises dry techniques that result in sharp separations based on mineral density utilising vibrations. The density of the separated particles is typically much higher than the air fluidised bed suspension density, so a critical granular state is formed at the sink-hole that is neither solid nor fluid-like.

The physical Sink-Hole Fluidiser equipment, similar to that at UON, has now been installed at Curtin and complementary experimentation is occurring in both nodes incorporating physical testing and CFD modelling. Artificial samples with tracer particles, as well as real (gold) samples sourced from industry are being investigated. Proof of concept for the technology has been established (to a TRL level between 2 and 3). The next phase is likely to be validation under continuous steady state conditions.

P1.3 Fine Particle Separation

19 Enhanced bubble-particle adhesion kinetics of ultrafine particles through bubble particle interaction in a shockwave at elevated pressure

Leader:

L/Prof Graeme Jameson (UON)

Key Personnel:

A/Prof Seher Ata (UNSW)

A/Prof Kym Runge (UQ)

PhD Student: Minuk Jung (UNSW)

The Concorde Cell is a novel flotation cell with the potential to achieve enhanced bubbleparticle adhesion kinetics of ultrafine particles through bubble particle interaction in a shockwave at elevated pressure. The project looks to perform bubble size measurements before and after retrofitting an existing flotation cell with ConcordeTM technology, in collaboration with Newcrest Mining. The Julius Kruttschnitt Mineral Research Centre (JKMRC) researchers have been involved in measurements of the cell at various air rates and two feed conditions. Anglo bubble sizer video images have been processed to determine bubble size as a function of cell operation.

17 Investigation of novel granular flow mechanism for achieving a density-based separation

Leader:

L/Prof Kevin Galvin (UON)

Key Personnel:

Prof George Franks (UOM)

Prof Chris Aldrich (Curtin)

PhD Student: Mitchell Craig (Curtin)

FLSmidth

18 Water-efficient electrostatic beneficiation Leader: Dr Peter Ireland (UON)

Key Personnel:

Prof Karen Hapgood (Swin)

Prof Grant Webber (UON)

Dr Kathryn Hadler, AI (Imperial College)

The Sink-Hole Fluidiser is a novel dry separation technology that has been shown to produce sharp separations based on density. The separation mechanism appears to be new, with the separation density typically much higher than the air fluidised bed suspension density – a critical granular state appears to form at the sinkhole that is neither solid or fluid-like. This project has developed the first stage of a fundamental discrete element model, essential for understanding the novel granular state that underpins the separation mechanism. The approach has identified key variables that influence the mechanism, helping to explain the high separation density. Curtin is using a complementary approach based on CFD to model the system.

20 Enhanced bubble-particle adhesion kinetics of ultrafine particles in a shear field at an air bubble sparger surface

Leader: Dr Mahshid Firouzi (UON)

Key Personnel:

L/Prof Kevin Galvin (UON)

A/ Prof Kym Runge (UQ)

PhD Student: Brady Wright (UON)

FLSmidth

The REFLUX™ Flotation Cell (RFC) has the potential to improve throughput per unit area as well as grade in flotation circuits. An experimental methodology has been established for capturing and analysing the bubble size and gas holdup in both two-phase flow and three-phase flow, important parameters in understanding the hydrodynamics of the RFC and recovery of minerals. It has been demonstrated for the first time the combined effect of counter-current washing and elevated salt concentration on the entrainment of gangue particles (silica), which is of great importance in high grade recovery of valuable minerals.

21 Fast flotation of fine particles

Leader: Prof Bill Skinner (UniSA)

Key Personnel:

L/Prof Kevin Galvin (UON)

PhD Student: Linda Ayedzi (UniSA)

FLSmidth

The REFLUX™ Flotation Cell creates an environment with rapid bubble-particle contacting and low entrainment of bubbles. The importance for fine particle recovery in real ore systems is still poorly understood. To this end, a lab-scale RFC has been installed at UniSA along with ancillary equipment (pumps, flowmeters, and valves). A new, fine nickel ore stream received from an industry partner will be investigated along with ultrafine composites produced by James Dankwah (through his work on Project 9).

Electrostatic separation techniques are not widely employed in the field of mineral separations. The current project aims to create models for droplet-particle collection and electric fields in new separator designs using the COMSOL Multiphysics software. A Python model architecture for aerosol-charged particle capture has been developed. A similar model architecture has been developed to model several different electrostatic separator types, allowing use of electric field data generated by finite-element modelling in COMSOL Multiphysics. A bench-scale electrostatic separator is being constructed to fit inside an existing environment chamber. This device will be used to validate the modelling results.

22 Counter current washing of a concentrated bubble column, quantifying the limits of flotation separability using novel release analysis

Leader: L/Prof Kevin Galvin (UON)

Key Personnel: Prof Yongjun Peng (UQ)

A/Prof Kym Runge (UQ)

PhD Students:

Siân Parkes (UON)

Jiarui Chen (UQ)

FLSmidth

The REFLUX™ Flotation Cell is a new flotation device that delivers counter-current washing via a concentrated bubbly-zone, with no froth. Strong wash water fluxes create a positive bias flux that delivers strong cleaning of the concentrate. Experimental systems have been established at UON and UQ, and strong progress made using critical minerals containing copper and nickel, as well as graphite. A novel method to benchmark flotation technologies was developed and applied to assess the RFC performance relative to a mechanical cell, kinetics, and cleaning. The work at UON has focused on copper and nickel using model and real ore systems, while UQ has worked on an entrainment model, supported by studies on graphite and the rejection of clays.