Abstract
The processing of sweated aluminum electronic scrap was investigated to develop methods for recovering the aluminum and concentrating the other metals, including copper, lead, gold, and silver, into a product that can be separated by known methods. Two molten-salt electrorefining processes were developed and tested. The first process utilized a three-layer refining cell with a bacl2-naf-alf3 electrolyte, which operated at 750 deg to 850 deg c. The second process used an all-chloride electrolyte of nacl-kcl-alcl3 at 750 deg to 800 deg c, with separate anode and cathode compartments. High-quality aluminum that averaged 99.8-percent pure in the three- layer cell and 99.6-percent pure in the compartment cell was recovered. Over 94 percent of the aluminum was recovered with cathode current efficiencies of approximately 90 percent in both methods. The copper, lead, tin, silver, gold, and other metals were concentrated threefold in an anode product. Separation of lead and part of the tin by liquation from this product seemed feasible. The anode product was smelted to prepare a 96-percent copper bullion that contained 690 ounces of silver and 65 ounces of gold per ton, with 98 percent recovery of these values.
