METHOD OF RECOVERING COPPER AND NICKEL FROM AMMONIACAL LEACHING SOLUTION CONTAINING COPPER AND NICKEL

摘要

Ammoniacal leach solutions containing nickel and copper (and possibly other base metal values) are treated by first extracting copper, leaving nickel in the raffinate. The nickel in the raffinate is subsequently extracted with an organic extractant. The nickel-loaded organic extractant is subsequently stripped with a highly concentrated ammonium salt solution to yield a strip concentrate from which nickel or nickel oxide is recoverable without electrolytic treatment. To prevent build-up of copper in the nickel extraction circuit, part or all of the organic extractant from the nickel strip circuit is recycled back to the copper extraction circuit where copper in the organic extractant is eventually stripped. In the copper extraction circuit, the nickel in the recycled organic extractant is replaced by copper from the aqueous layer, preventing build-up of nickel in the organic extractant leaving the copper extraction circuit.