The Influence of Electrolyte Chemistry and Anode Temperature on the Anode Effect in Aluminum Electrolysis

This study examines how electrolyte composition and anode temperature govern the occurrence and characteristics of anode effects, particularly high-voltage anode effects (HVAE) and low-voltage anode effects (LVAE), in aluminum electrolysis. Combining electrolysis experiments with sessile drop measurements of contact angles between the electrolyte and carbon anode, X-ray photoelectron spectroscopy and gas chromatograph analyses, the synergistic mechanisms of LiF and KF on interfacial wettability, bubble dynamics, electrode polarization, and the formation of CF x passivation layers are elucidated. The results indicate that the high-Li electrolyte (6Li3K) compromises wettability, promoting LVAE and continuous low-concentration CF 4 emissions. In contrast, the high-K electrolyte (2Li6K) facilitates the formation of highly fluorinated CF x films, leading to HVAE. These findings highlight the importance of optimizing electrolyte formulation and anode thermal management to mitigate anode effects and reduce PFC emissions, thereby supporting the development of more sustainable and environmentally friendly aluminum smelting processes.