GB1474973A - Production of copper - Google Patents

Abstract

1474973 Copper recovery SHERRITT GORDON MINES Ltd 10 Sept 1974 [10 Sept 1974] 39376/74 Heading C1A Copper is recovered from cupriferous sulphidic materials by: (1) leaching the materials under oxidizing conditions with a leach liquor containing (NH 4 ) 2 SO 4 ; (2) separating the copper-containing aqueous leach liquor from the insoluble residue; (3) contacting the coppercontaining leach liquor with an organic extractant for copper, the extractant being of the ionexchange type, having substantially greater affinity for Cu than the other metals present, and being dissolved in a water-immiscible organic diluent; (4) separating the extracted aqueous phase from the organic extractant; (5) treating at least a portion of the de-coppered leach liquor to recover NH 3 and to remove sufficient SO 4 -- ions to maintain a steady concentration of SO 4 -- in the system; (6) recycling at least a portion of the water and NH 3 from (5) to step (1); (7) contacting the solution of Cu-rich organic extractant with an aqueous solution of H 2 SO 4 to strip the copper from the extractant; (8) separating the aqueous acid phase containing CuSO 4 from the organic extractant, which is recycled to step (3); (9) recovering copper in an elemental form by a copper winning operation whilst simultaneously generating H 2 SO 4 in a spent acid solution and; (10) utilizing at least part of the spent acid solution from (9) for the stripping of Cu from the copper bearing extractant in step (7). In a preferred embodiment the SO 4 -- content of the leach solution is kept at the right concentration by treatment of a portion with Ca(OH) 2 . In another, zinc is removed from the leach solution by gassing with CO 2 , and thus precipitating Z n or CO 3 . The sulphur content of the raw materials may be lowered by a preliminary sulphating roast (Fig. 4, not shown).