Electrodeposition of Manganese Metal and Co-production of Electrolytic Manganese Dioxide Using Single-membrane Double-chamber Electrolysis

Given the problems of high energy consumption, low resource utilization, and severe environmental pollution in traditional electrolytic manganese or manganese dioxide, this study puts forth a single-membrane double-chamber electrolysis method for the cathodic electrodeposition of manganese. Anode co-production of electrolytic manganese dioxide and recovery of sulfuric acid in the anode chamber enable efficient recovery and utilization of resources. The effects of Mn2+ concentration, current density, electrolysis temperature, cathode (NH4)2SO4, and anode H2SO4 concentration on electrodeposition were investigated. At the cathode concentration of 40 g/L Mn2+, initial pH = 7.0, 120 g/L (NH4)2SO4, current density 400 A/m2; and anode concentration of 40 g/L Mn2+, 0.6 mol/L H2SO4, current density 800 A/m2, 60 mm plate spacing, electrolysis temperature of 40 °C, and electrolysis time of 6 h; the yield of manganese dioxide reached 75.1 %, electrolytic manganese dioxide yield was 23.6 %, acid recovery was 62.3 %, and the energy consumption was 5701 kW h t−1. The surface of metal manganese produced at the cathode was smooth and dense, with a silver-white metallic luster and uniform growth of each phase. The electrolytic manganese dioxide (EMD) of the anode product was α-MnO2, and its microstructure was characterized by a spherical particle structure. The particle size was uniform and showed a honeycomb structure. Thus, the application of a single-membrane double-chamber manganese production system can effectively solve the environmental pollution caused by heavy metal wastewater and provide efficient recovery and utilization of resources, which has good economic and social benefits