An Electrolytic Process Using an Ag Cathode and Vacuum Distillation for Mg Metal Production from MgO

A molten salt electrolysis process using a silver (Ag) cathode, followed by vacuum distillation was systematically investigated with the purpose of producing high-purity magnesium (Mg) metal from magnesium oxide (MgO). The electrolysis of MgO was conducted using Ag cathode and carbon (C) anode in magnesium fluoride (MgF2)-lithium fluoride ( LiF) molten salt at 1083-1163 K with the cathodic current density of 0.213-0.223 A cm(-2). After the electrolysis, 8.53-21.5 mass% Mg-Ag alloys were produced through the electroreduction of MgO with the average cell voltage of 1.95-2.11 V, and the current efficiency was 74.6-85.1%. When the Mg alloys obtained after the electrolysis of MgO were distilled at 1300 K under vacuum, Mg metal with a purity of 99.9998% was produced under certain conditions. Therefore, the developed Mg production process shows the feasibility of the environmentally friendly and efficient production of high-purity Mg metal from MgO through the molten salt electrolysis using an Ag cathode, followed by vacuum distillation. [GRAPHICS]

Automated summary

A molten salt electrolysis process using an Ag cathode and vacuum distillation was investigated to produce high-purity Mg metal from MgO. The electrolysis of MgO was conducted at 1083-1163 K using an Ag cathode and a C anode in MgF2-LiF molten salt. After electrolysis, Mg-Ag alloys were produced with mass percentages of 8.53-21.5%, an average cell voltage between 1.95-2.11 V, and a current efficiency of 74.6-85.1%. Distilling the Mg alloys at 1300 K under vacuum resulted in Mg metal with a purity of 99.9998% under specific conditions. The developed Mg production process demonstrates the feasibility of environmentally friendly and efficient production of high-purity Mg metal from MgO through molten salt electrolysis using an Ag cathode, followed by vacuum distillation.