Towards green magnesium preparation using a recyclable argon plasma anode for continuous electrolysis in molten chlorides

In this study, we introduce a continuous, carbon-free approach to magnesium electrolysis using stable argon plasma as the anode. The argon plasma anode operates via two distinct electrochemical stages: argon ionization at an average potential of 347.3 ± 95.3 V and chlorine evolution at 124.5 ± 9.0 V. A protective boron nitride (BN) coating on the tungsten collector filament significantly reduces corrosion.

Atomic emission spectroscopy confirms the presence of Ar+ ions, whose concentration increases with current. Thermodynamic calculations and reaction analysis demonstrate that Ar+ facilitates chloride oxidation via the reaction: 2Ar+ + 2Cl- → 2Ar + Cl2. This work establishes the feasibility of argon plasma as an inert anode for chloride-based molten salt electrolysis, offering a sustainable alternative for magnesium production and potential applications in other high-temperature corrosive environments.