[en] The platinum group metal (PGM) industry is currently reliant on the crush-mill-float-smelt-refine route to process PGM ores. However, there are many instances where this route would not be feasible. An alternative process route has been developed which involves heap bioleaching to extract base metals followed by heap reclamation and a water wash step, leading into heap cyanide leaching to extract precious metals. This process was evaluated through test work on samples of Platreef ore using laboratory scale columns. After 304 days 75% Ni and 93% Cu were extracted in the bioleach experiment at 65°C, and after 60 days 58% Pt, 99% Pd and 90% Au in the follow-up cyanide leach experiment at 50°C. A preliminary process flow sheet has been developed around this. Analysis via a mineral liberation analyser showed that the remaining Pt was in the form of the mineral sperrylite, which appeared to be slow leaching in cyanide in comparison to the other mineral types. Analysis of cyanide effluent solution showed high levels of thiocyanate, which present an environmental risk for disposal and high consumption of cyanide. Further studies to develop the process for commercial application in the South African PGM industry are outlined.
Disciplines :
Chemical engineering
Author, co-author :
Mwase Malumbo, James ; Université de Liège > Département ArGEnCo > Traitement et recyclage des matières minérales
Language :
English
Title :
Heap leaching for sustainable development in the South African PGM industry
Publication date :
June 2014
Event name :
Hydrometallurgy 2014, 7th International Symposium
Event organizer :
The Metallurgy and Metals Society of CIM
Event place :
Victoria, Canada
Event date :
22-06-2014 to 25-06-2014
By request :
Yes
Audience :
International
Main work title :
Proceedings of Hydrometallurgy 2014, 7th International Symposium, Vol. II