Penetration behavior of electrolyte into graphite cathode in NaF−KF−LiF−AlF3 system with low cryolite ratios

Abstract

The current study focuses on the electrolyte penetration of the graphite cathode in a NaF−KF−LiF−AlF3 aluminum-electrolysis system with a cryolite ratio of 1.3. It involves a comprehensive investigation of the electrolyte in the cathode before and after electrolysis by X-ray diffraction and analysis of the results by semi-quantitative calculation in MAUD. The results show that KF can promote electrolyte penetration, with higher KF contents resulting in greater penetration. During electrolyte penetration, K2NaAlF6 and solid solutions containing KF play important roles in KF-containing systems. LiF effectively prevents the electrolyte penetration, while the Na3Li3Al2F12 phase plays an essential role in systems with high LiF contents.