Bolger, Paul T. and David C. Szlag. CREATING A CLOSED-LOOP METAL PLATING PROCESS USING ELECTROCHEMISTRY
U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Mail Stop 443, Cincinnati, OH 45268 (bolger.paul@epa.gov)
This research aims to increase resource productivity within an electrolytic nickel plating process while simultaneously creating a near zero discharge operation. The work is made feasible by advances in anion exchange membrane manufacture permitting their insertion in electrowinning cells for pH control and acid concentration. In this study an electrowinning cell with a high-surface area cathode and an acid concentrating anion exchange membrane is placed at the rinse water stage of an electrolytic nickel plating process. This cell allows dual electrode use recovering nickel metal from the rinse water at the cathode (which can be recycled to the plating bath) and generating a sulfuric/hydrochloric acid mixture at anode which can be used in the pickling baths to clean metal parts before plating. This cell replaces the traditional ion exchange process for treating rinse waters eliminating regeneration chemicals/waste while producing useful process materials.