Argon anodic plasma inert anode for Low-Temperature aluminium electrolysis

The aluminum industry is one of the major causes of CO2 emissions into the atmosphere, mainly caused by carbon anode consumption and the emission of perfluorocarbon gases. Carbon anodes are consumed by anodic reactions in the standard technology. The environmental constraints and the costs associated with the utilization of carbon anodes have, for many decades, led to the look for non-consumable anodes, called “inert anodes,” considered for years to be the future of aluminum production. However, the current research on inert anodes is limited to metal, ceramic, cermet, and gas anodes and remains impotent in solving the difficulties of anode consumption, CO2, and other greenhouse gas emissions. Here, we propose the utilization of argon plasma as an inert anode for aluminum electrolysis. The results from emission spectroscopy analysis and Density Functional Theory (DFT) calculations depict a production of positively charged argon ion (Ar+) at the anode region, which infuses into the electrolyte and reacts electrochemically with the oxy-fluoro aluminate complexes (Al2OF6)2-. For a current ≤ 0.4 A, the oxygen evolution occurs anodically from 2Al2OF62- + 4Ar+ → 4AlF3 + O2 + 4Ar, with no argon consumption. Furthermore, the aluminum is reduced cathodically, and the decomposition reaction is 2Al2O3 → 4Al + 3O2. This innovative approach enables carbon-free aluminum electrolysis, a large-scale reduction in greenhouse gas (GHG) emissions, which can be extended to similar electrolytic industries.