Abstract:The electro-deoxidation of TiO₂ was investigated in molten CaCl₂. Back electromotive force measurements, constant voltage electrolytic experiments, contrast experiments of different cathodes, and cyclic voltammograms were carried out for solving the puzzle of reduction mechanism. The results showed that the reduction process proceeded step by step. TiO₂ was first reduced to Ti₃O₅ or Ti₂O₃, and then further reduced to Ti₃O, Ti₂O, TiO and Ti. In addition, direct electrochemical reduction of titanium dioxide was the primary cathodic reaction; meanwhile, some calciothermic reduction reactions also happened at the cathode. Cyclic voltammograms of solid titanium dioxide and molybdenum wire in molten salts with different compositions were also studied.

Key words: titanium; electro-deoxidation; reaction mechanism; molten salt