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

Abstract

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.

Keywords

• single-membrane double-chamber
• manganese
• electrolytic manganese dioxide