The effect of ledge toe and thin film formation on cathode voltage drop in aluminium electrolysis cells

Abstract

Cathode voltage drop (CVD) in aluminium electrolysis cell has been studied with considerations to the presence of the ledge toe and a thick deposit along the central channel. In this study, the impact of the presence of a thin film between the ledge toe and the thick deposit along the central channel was also considered. Laboratory experiments were performed to study the interrelations in-between the CVD and the cathode material, the heat transfer rate and the covering area by the ledge toe. The ledge toe and the thin film were modelled considering an aluminium carbide layer covered by a sludge deposit. The electrical properties of these layers have been varied to model previously studied observations of composition and morphology. CVD measurements in industrial cells were used to support the model.