Abstract
Metallic manganese has been obtained by an electrowinning process. Since the current efficiency of manganese electrowinning is low, it need to be improved. In this study, we focused on the separation of a cathode and anode cell to improve current efficiency by during the oxidation of manganese ions at the anode electrode. A copper sheet, a platinum coil, and an Ag/AgCl electrode were used as the cathode, anode, and reference electrode, respectively. The cathode and anode cells were separated by an ion-exchange membrane. The optimum manganese ion concentration was 0.7 mol dm-3, and the optimum initial pH was 7; where1.0 mol dm-3 of ammonium sulfate was added as a pH buffer and complexing agent into 0.7 mol dm-3 of a manganese solution. Electrowinning on a manganese electrode was easier than on a copper electrode. Agitation of the solution did not influence the current efficiency in this study. However, an increase in the bath temperature decreased the current efficiency. The maximum current efficiency was 82.6%, and the purity of manganese was 99.97%. The concentration of cobalt ion contamination influenced the manganese electrowinning, and stable manganese electrowinning requires that the cobalt concentration in the electrolyte be less than 10 mg dm-3.
