An electroanalytical study of electrode reactions on carbon anodes during electrolytic production of aluminum

摘要

In connection with the electrolytic production of aluminum the anodic reactions have been studied on carbon microelectrodes by voltammetry and chronoamperometry. Anode gases have been analyzed by gas chromatography on-line during controlled-potential electrolysis in a laboratory-scale aluminum reduction cell. When the voltage exceeds a critical value (about 3 V vs Al/Al~(3+)), the cell current drops precipitously. We attribute this to the formation of a highly resistive film on the surface of the anode. The existence of this putative film was shown to be strictly potential dependent - the film could be formed and removed at will be regulation of applied potential. The rate of PFC generation was found to vary with the magnitude of the anodic overpotential. A PFC reduction strategy that takes into account the design of the power supply is proposed.