Patent ID: 9540706
Date: 2017-01-10
CPC Classifications: C21B,C22B,Y02P

Claim:
1. A hydrometallurgical process for extracting platinum group metals (PGMs), gold, silver and base metals from a flotation concentrate, the process comprising the steps of: (a) subjecting the concentrate to modified pressure oxidation to selectively separate the base metals from the PGMs, gold and silver in a sulfate medium, wherein sulfide minerals are partially or completely oxidized, to produce a product slurry containing base metal sulfates in solution and a solid residue containing PGMs, gold and silver along with sulfate and elemental sulfur; (b) filtering the product slurry from step (a) to obtain the solid residue containing PGMs, gold and silver along with sulfate and elemental sulfur and the filtrate containing the base metal sulfates; (c) subjecting the solid residue from step (b) to thermal treatment comprising: (d) recovering PGMs, gold and silver from the treated solid residue of step (c) by leaching in a chloride leaching medium, thereby extracting said PGMs, gold, silver and base metals.