THE ELECTRODEPOSITION OF MANGANESE FROM AQUEOUS-SOLUTIONS OF MNSO4 .4. ELECTROWINNING BY GALVANOSTATIC ELECTROLYSIS

An investigation of manganese electrowinning from aqueous solutions of MnSO4 was carried out. The galvanostatic electrolysis tests were made using a laboratory installation that provides a uniform current distr ibution and allows continuous washing of the cathodic surface with fre sh electrolyte. Two types of electrolytes: a synthetic electrolyte (SE ), containing MnSO4 105 g/l and (NH4)(2)SO4 1 M, and an industrial ele ctrolyte (IE), having the same composition as the SE and traces of zin c, were used. The influence of H2SeO3, as additive, and traces of zinc in the IE solution were found beneficial for the cathodic current eff iciency (phi) and specific energy consumption (W-S). For the IE soluti on at i = 500 A/m(2), pH(cat) = 7-8, T approximate to 20 degrees C, in the presence of 1 mM H2SeO3, phi reached 82% and W-S was 6.8 kWh kg(- 1) for a conversion of about 44%.