Extraction of copper, nickel and cobalt using alkylaromatic sulfonic acids and chelating amines

Claim 1

A process for recovering a first metal value selected from the group consisting of cobalt, copper and nickel from an acidic, aqueous ore leach liquor containing said first metal value and a second metal value, the process comprising (1) contacting said leach liquor at a pH of below about 3.5 with a solvent-extractant system comprising: (a) an alkylaromatic sulfonic acid having a molecular weight of at least about 400, (b) a chelating amine wherein the pKa value for the amine group is in the range of from about 3 to about 9 and further having at least two coordinating centers in the molecule, at least one such center being a ring nitrogen, and (c) a water-immiscible diluent for (a), (b) and metal complexes of (a) and (b) to provide a solution of the first metal value in the extractant, said combination of (a) and (b) being characterized as having superior selectivity for said first metal value over (b) alone, (2) separating the thus-formed solution from the aqueous raffinate depleted in the first metal value, and (3) recovering the first metal value from the separated solution.