Electrochemical behavior of graphite anode during anode effect in cryolite molten salts
(1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. Engineering Research Center for Process Technology of Nonferrous Metallurgy of Ministry of Education,
Northeastern University, Shenyang 110004, China)
2. Engineering Research Center for Process Technology of Nonferrous Metallurgy of Ministry of Education,
Northeastern University, Shenyang 110004, China)
Abstract: Anodic electrochemical behavior was studied on graphite anode at 1000 °C in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.
Key words: anode behavior; aluminum electrolysis; perfluorocarbons; anode passivation