Fundamental Study of a Novel Electrolytic Process Using a Cu Cathode in MgF2-LiF-KCl Molten Salt for Producing Mg Metal from MgO

Abstract

© 2022, The Minerals, Metals & Materials Society.A fundamental study on the molten salt electrolysis of magnesium oxide (MgO) using a copper (Cu) cathode was conducted to develop a novel process for producing magnesium (Mg) metal. The influence of the electrolysis temperature, the concentration of Mg in the Mg-Cu alloy, and cathodic current density on the current efficiency was investigated. In addition, the reaction between the alumina (Al2O3) crucible and the Mg-Cu alloy contained in the crucible was analyzed. In the experiments, 1.42–1.63 A was applied to the electrolysis cell using Cu cathode and graphite anode at 1043 K and 1173 K for 9.5–15.0 h in an argon (Ar) gas atmosphere. When the concentration of Mg ranged from 9.25–14.2 mass%, the Mg alloys of MgCu2 and Cu (Mg) mixtures were obtained, with 72.5–91.7% of the current efficiency under certain conditions. Thus, the feasibility of the novel and effective electrolytic method for the production of Mg was demonstrated.