Patent ID: 7438874

Claim:
A process for the extraction of a base metal value from an ore or concentrate containing copper and the base metal, comprising the steps of: subjecting the ore or concentrate to pressure oxidation at 115° C. to 175° C. in the presence of oxygen and an acidic solution containing halide and sulphate ions to produce a product solution containing copper and the base metal; subjecting the product solution to a copper extraction process for recovering copper from the solution; recycling the product solution to the pressure oxidation without recovering the base metal therefrom to effect a build-up of the base metal in the product solution and, after building up the base metal in the product solution, splitting the product solution into a major portion and a minor portion after the copper extraction process, the major portion and the minor portion both containing the base metal; recycling the major portion of the product solution to the pressure oxidation without recovering the base metal therefrom; and recovering the base metal from said minor portion; and wherein the base metal is selected from one or more of the group consisting of Ni and Co.