Reducing Carbon Contamination by Controlling CO32− Formation During Electrochemical Reduction of TiO2

Molten salt electrolysis is a clean and low-cost Ti production technology that allows the direct conversion of metal oxides into metals or alloys via electrochemical reduction. However, carbon contamination can always be found due to the formation of CO 3 2− and erosion of the graphite anode during electrolysis. Herein, we explore the reduction of carbon contamination by controlling CO 3 2− formation. By adjusting the electrolyte composition, it is possible to improve the wettability between the molten salt and the anode and reduce the O 2− solubility in molten salt to reduce CO 3 2− formation. This approach reduces carbon contamination, and the current efficiency is also increased by adding 30 wt pct KCl to pure molten CaCl 2 . The carbon content in the cathode product decreased by 94 pct and the current efficiency was increased by 51 pct, compared with electrolysis in pure CaCl 2 molten salt. In addition, the anode corrosion decreased, and the weight loss of the graphite anode decreased by approximately 65 pct after 18 hours of electrolysis.