EMD Deposition on Mn_2O_3/Ti Anode for Manganese Recovery from Zinc Electrowinning Solutions

摘要

Electrolytic manganese dioxide, EMD, is the positive electrode material of primary batteries and the raw material of LMC used as the positive mass of lithium ion batteries and is currently produced by anodic deposition on and harvesting from a titanium anode in acidic manganese sulfate solutions prepared by dissolving high purity of manganese sulfate into sulfuric acid solutions. This paper presents an alternative method of EMD production using a novel anode, Mn_2O_3 coated titanium, at lower operating temperature than the current process to explore a possibility of manganese recovery from zinc electrowinning solutions. The Mn_2O_3/ Ti anode prepared by thermal decomposition of a precursor solution containing Mn (II) showed the anodic deposition of MnO_2 by constant current electrolysis and the current efficiency was 95% in maximum, while the current efficiency and the crystallographic structure of deposited MnO_2 depended on the current density, the electrolysis time, the bath temperature, and the concentration of Mn(II). The deposited MnO_2 was successfully harvested from the anode and the recovery rate was 98%.