Silver as anode in cryolite alumina base

This study investigates the anodic behavior of silver in cryolite—alumina-based melts, focusing on its potential as an inert material for aluminium electrolysis. Utilizing a working temperature of approximately 960°C, commensurate with industrial practices, silver's stability was tested at 870°C within a specific acidic electrolyte mixture. The electrolyte, rich in Na3AlF6, AlF3, CaF2, LiF, and Al2O3, exhibited a melting point around 850°C. The investigation employed voltammetry measurements to analyze the electrochemical behavior of the silver anode, revealing that an oxidation reaction occurred at a potential below the oxygen evolution threshold. Notably, silver demonstrated instability under conditions conducive to oxygen evolution, leading to observable degradation throughout the electrolysis process. These findings underscore the challenges posed by the use of silver as an anode material in electrolysis, highlighting the necessity for further exploration of alternative inert materials that could mitigate environmental concerns associated with current carbon anodes used in aluminum production.