1. IN A HYDROMETALLURGICAL PROCESS FOR RECOVERING A SUBSTANTIALLY NICKEL-FREE COBALT SOLUTION FROM A LIQUOR CONTAINING DISSOLVED NICKEL AND COBALT WHICH COMPRISES ADJUSTING THE SOLUTES CONTENT OF SAID LIQUOR TO PROVIDE ABOUT 5 MOLS OF AMMONIA FOR EACH MOL OF DISSOLVED COBALT PLUS ABOUT 5 MOLS OF AMMONIA FOR EACH MOL OF DISSOLVED NICKEL A SULFATE ION CONCENTRATION AT LEAST SUFFICIENT TO SATISFY THE DISSOLVED COBALT CONTENT IN ITS TRIVALENT STATE AND DISSOLVED NICKEL IN ITS BIVALENT STATE; OXIDIZING THE ADJUSTED LIQUOR WITH A SULFURIC ACID INTO SAID BEARING OXIDIZING GAS; INTRODUCING SULFURIC ACID INTO SAID OXIDIZED LIQUOR TO PRODUCE A HYDROGEN ION CONCENTRATION AT LEAST EQUIVALENT TO A PH OF ABOUT 4, WHEREBY A SUBSTANTIALLYH COBALT-FREE, NICKEL-BEARING PRECIPITATE IS FORMED; AND SEPARATING SAID PRECIPITATE, LEAVING A SOLUTION CONTAINING COBALT AS ACID SOLUBLE, ACID STABLE COBALTIC AMMINE SULFATE AND A MINOR AMOUNT OF NICKEL IN ITS BIVALENT STATE, THERE BEING INSUFFICIENT DISSOLVED BIVALENT COBALT TO FORM A COBALTOUS-BEARING PRECIPITATE, THE IMPROVED METHOD ADAPTED TO DECREASE THE NICKEL CONTENT OF SAID SOLUTION WHICH COMPRISES: INCREASING THE COBALTOUS ION CONTENT OF SAID SOLUTION SUFFICIENT TO PROVIDE A COBALTOUS ION TO NICKELOUS ION RATION OF AT LEAST ABOUT 1:1 WHEREBY COBALTOUS-NICKELOUS-AMMONIUM SULFATE IS PRECIPITATED, AND SEPARATING SAID PRECIPITATE.