Patent ID: 6171564
Filing Date: 2001-01-09
Classification: C22B,Y02P

Abstract:
A process for the extraction of metal from an ore or concentrate, containing nickel and/or cobalt values and other metals, comprising the steps of:subjecting the ore or concentrate to acid leaching under pressure, at pH.ltoreq.2, to obtain a liquor containing nickel and/or-cobalt values in addition to non-nickel and non-cobalt metals;subjecting the liquor to a first precipitation stage at a pH of about 5 to 6 to produce a solid containing the non-nickel and non-cobalt metals and a resultant solution containing the nickel and/or cobalt values;subjecting the resultant solution to a second precipitation stage at a pH of about 7 to 8 to produce a solid containing nickel and/or cobalt and a nickel and cobalt depleted liquor, wherein said acid leaching under pressure comprises pressure oxidation in the presence of oxygen and an acidic solution containing halide and sulphate ions.