Electrochemical Deoxidation of Titanium in Molten MgCl₂-HoCl₃

Abstract

A new electrochemical deoxidation method is proposed for Ti, wherein a mixture of magnesium chloride and holmium chloride (MgCl2-HoCl3) is used as a flux. In the new process, Ti and C are used as the cathode and anode, respectively. Mg is deposited on the Ti cathode, which reduces the O in Ti to oxide ions (O2). The activity of the generated O2- (aO2-) in the system was effectively maintained at a low level by the formation of holmium oxychloride (HoOCl) and further decreased by the electrochemical oxidation reaction on the anode. By applying a voltage of 3.0 V between the cathode and anode at 1173 K, Ti was effectively deoxidized to approximately 1000 mass ppm O. Based on the results, in this study, an electrochemical cell, that simultaneously deoxidize Ti scrap or powders and recover HoOCl, is designed.