Preparation of titanium by electrochemical reduction of titanium dioxide powder in molten SrCl2–KCl

SrCl 2 -based molten salt system, i.e. SrCl 2 –KCl, was selected to enhance the electrochemical reduction of TiO 2 powder via OS process, utilizing both high solubility of SrO and Sr in SrCl 2 melt and extremely high oxygen affinity of active metal (Sr). In this study, titanium dioxide particles were reduced in a three-electrode cell consisting of a sinking Mo cathode in molten SrCl 2 –KCl, and the reduction mechanism and reaction pathway of the oxide powder were explored by using cyclic voltammetry and potentiostatic electrolysis methods. Electrochemical tests showed that with small addition of SrO in the melt TiO 2 firstly transformed to SrTiO 3 , then reduced to Ti–O solid solution and finally converted to metallic titanium; electro-deoxidization of TiO 2 powder initiated only at the early stage of electrolysis and electro-metallothermic reduction mechanism dominated the deoxidization reaction pathway. Metallic titanium powder containing 0.58 wt% oxygen with average particle size around 1 μm was produced in the 80 wt% SrCl 2 -20 wt% KCl bath at 800 °C with 1 wt% SrO added to the melt.