Faculty of Engineering, Built Environment and Information Technology
School of Engineering
Department of Materials Science and Metallurgical Engineering
Selected Highlights from Research Findings
South Africa is the world's leading supplier of platinum. The nature of the mined platinum ore deposits is changing over time. A notable recent shift is the increasing use of telluride-rich deposits, such as the Platreef. After milling, the platinum-group metals in the ore are concentrated by froth flotation, where selected mineral particles, typically a tenth of a millimetre or less in diameter, are recovered by causing the particles to attach to air bubbles which swarm through the stirred ore-water mixture. Poor recovery of tellurides (which contain much of the palladium in some ores) has sometimes been found in practice. Research probed the surface chemistry and tendency of telluride minerals to attach to bubbles (hydrophobicity) while under electrochemical control. The surface reactions which give hydrophobicity do indeed occur - so the tellurides should float. This means that the dynamics of the interaction between bubbles and particles must be behind poor recovery, and not creation of hydrophobicity itself. These dynamics will be the focus of further research.
Contact person: Prof PC Pistorius.
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