Patent ID: 7736606
Filing Date: 2010-06-15
Classification: C22B,Y02P

Abstract:
1. A process for leaching a value metal from an unroasted sulfide ore material containing said value metal, comprising the step of leaching the unroasted sulfide ore material at atmospheric pressure with a lixiviant consisting essentially of hydrochloric acid, magnesium chloride and an oxidant selected from the group consisting of alkali metal peroxide, alkali metal perchlorate, ammonium perchlorate, magnesium perchlorate, alkali metal chlorate, alkaline earth metal perchlorate, chlorine, alkali metal hypochlorite, hydrogen peroxide and peroxysulfuric acid, and mixtures thereof to obtain a leachate and a solid residue, wherein gold and platinum group metals in the sulfide ore material essentially remain in the solid state, said leaching step being carried out at a temperature of from 75° C. to the boiling point of the lixiviant at atmospheric pressure, said lixiviant having a redox potential in the range of 250 to 600 mV.