Anion-exchange separation of cobalt from nickel

An anion-exchange method has been developed for the separation of cobalt from nickel, based on the observation that from a malonic acid solution containing sodium nitrite, cobalt is preferentially adsorbed by the exchanger but nickel passes through. The cobalt is eluted with 2M ammonium chloride in dilute ammonia solution. Prom an ammonium malonate solution containing chloride and nitrate, cobalt is quantitatively electro-deposited on a platinum cathode to give a bright, adherent deposit. Nickel is deposited from a solution of similar composition.