Preliminary studies on the electrochemical recovery of Zn and Cd from effluent produced by a zinc refinery plant using a filterpress reactor

Abstract

BACKGROUND Fundamental studies are reported investigating the electrochemical deposition of cadmium and zinc contained in solutions from a zinc electro-refining plant. This work also analyzes the performance of a filterpress electrochemical reactor used in the recovery of zinc and cadmium from this effluent. RESULTS The cathodic polarization curves showed electrochemical processes with mixed control for 304 SS and Al. The cyclic voltammetry studies on stainless steel revealed the presence of metal deposits at low current densities, whereas Zn and Cd were preferentially deposited at high overpotentials. The greatest recovery of cadmium (19%) and zinc (24%) at jap = 4 mA cm-2 was obtained with a 304 SS cathode and t = 180 min. The SEM micrographs of cathode plates confirmed the presence of cadmium and zinc deposits. In addition, EDS analyses revealed that the composition of such deposits depends on the deposition time and the cathode material. CONCLUSION A continuous filterpress electrochemical reactor with 304 SS and Al cathodes exhibited a promising performance level for cadmium and zinc recovery from industrial solutions.