Influence of current density on the reduction of TiO2 in molten salt (CaCl2 + CaO)

Abstract

Titanium dioxide (TiO2) was successfully reduced at 1223 K by calcium, which was deposited due to the molten salt electrolysis of CaO dissolved in CaCl2. The current density and the Ca concentration near the cathode were changed by varying the electrodes* surface areas and the distances between an anode and cathode, respectively. At the initial stage of reduction, metallic Ti powder with a lower oxygen concentration was obtained at a lower current density; in this case, most of the electrochemically deposited Ca was efficiently used for reduction. Meanwhile, at the final stage of deoxidation, Ti powder with a much lower oxygen concentration was obtained at a higher current density. In order to obtain metallic powder with a low oxygen concentration, the formed Ca should penetrate the inner part of the sintered sample. © 2009 The Japan Institute of Metals.