Investigation of the Reduction Electrochemistry of Titanium Oxides in Molten Calcium Chloride using a Cavity Electrode

Linear sweep voltammetry has been conducted on TiO₂, Ti₃O₅, Ti₂O₃, TiO and CaTiO₃ powders placed inside a metallic cavity electrode. Using each of the lower oxides has helped to isolate the immediate electrochemical reduction step from any previous electrochemical or chemical events. The voltammetry work has confirmed the stepwise reduction of TiO₂ to titanium as predicted by thermodynamic predominance diagrams for the Ca-Ti-O-Cl system. It is found that a TiO precursor reduces to titanium, without forming CaTiO₃. The latter is an insulating intermediate phase whose formation is encouraged by the rising local oxide activity at the cathode surface during reduction. It is suggested that TiO might be more suitable as a cathode precursor for the industrial production of titanium metal.