The electrowinning of dilute zinc sulfate solutions in a fluidized bed electrochemical reactor

Abstract

A cylindrical, fluidized bed electrochemical reactor (FBER), was employed to electrowin dilute zinc sulfate solutions containing 2.5 - 15 gr/1 zinc. The planar electrodes used in the industrial electrowinning of zinc requires 50 - 65 gr/1 zinc. A low acid catholyte solution of 5 gr/1 is the maximum concentration necessary for the efficient recovery of zinc. The addition of 60 gr/1 of Na^SO^ electrolyte improved both the catholyte conductivity and current efficiency. The optimum current efficiency and current density were obtained using a particle size of +355-500 microns, and a bed width of 1.3 cm. At a zinc concentration of 15 gr/1, the FBER could be operated at current densities and volumetric reaction rates greatly exceeding that of a conventional planar electrowinning cell.