The electrodeposition of manganese from aqueous solutions of MnSO 4. IV: Electrowinning by galvanostatic electrolysis

Abstract

An investigation of manganese electrowinning from aqueous solutions of MnSO 4 was carried out. The galvanostatic electrolysis tests were made using a laboratory installation that provides a uniform current distribution and allows continuous washing of the cathodic surface with fresh electrolyte. Two types of electrolytes: a synthetic electrolyte (SE), containing MnSO 4 105 g/l and (NH 4) 2SO 4 1 M, and an industrial electrolyte (IE), having the same composition as the SE and traces of zinc, were used. The influence of H 2SeO 3, as additive, and traces of zinc in the IE solution were found beneficial for the cathodic current efficiency (Φ) and specific energy consumption (W s). For the IE solution at i = 500 A/m 2, pH cat = 7–8, T ∼ 20°C, in the presence of 1 mM H 2SeO 3, Φ reached 82% and W s was 6.8 kWh kg −1 for a conversion of about 44%.