Energy-efficient and advanced electrowinning of metallic manganese within a novel H+ exchange membrane cell using a Ti/IrO2−RuO2−SiO2 anode

Abstract

Coated Titanium Anodes (CTAs) exhibit significant potential in addressing the high energy consumption challenge inherent in current manganese electrowinning processes. However, the electrodeposition of manganese dioxide (MnO2) at the anode limits the utilization of CTAs in conventional manganese electrolytic cells. Herein, a novel H+ exchange membrane (HEM) electrolytic cell was proposed and applied to manganese electrowinning employing Ti/IrO2 − RuO2 − SiO2 anode. The HEM electrolytic cell is a three-chamber electrolytic reactor consisting of cathode chamber, acidification chamber and anode chamber separated by woven terylene diaphragm and HEM. The results indicated that after 24 h of electrowinning, the cathodic current efficiency (CE) of 85.1 % was achieved, along with a specific energy consumption (EC) of 4189 kW·h/t. Compared to conventional industrial electrowinning technology, this represents an increase in CE by more than 15 % and a reduction in EC by over 1400 kW·h/t. The unique structure of the HEM electrolytic cell effectively prevents MnO2 deposition, ensuring the functionality of the CTAs and eliminating the generation of anode mud. Additionally, the H+ from the oxygen evolution reaction at the anode is collected and concentrated in the acidification chamber. This resulted in a spent electrolyte with 15.2 g/L H2SO4, enabling its reuse in extracting manganese ores. Employing the HEM electrolytic cell with a Ti/IrO2 − RuO2 − SiO2 anode for manganese electrowinning is therefore considered an energy-efficient and clean approach. It is highly recommended for saving energy and reducing carbon emissions in industrial processes.