Calciothermic Reduction of TiCl4 Gas during the Electrolysis of CaCl2 Melt

Abstract

The calciothermic reduction of TiCl4 gas was studied firstly by using Ca-CaCl2 melt, to whose surface the gas was blown. The fine Ti particles settled down in the crucible, when the concentration of dissolved Ca was > 2 mol% at 1173 K. When < 2mol%Ca, a part of TiCl4 gas was dissolved probably as TiCl3 or TiCl2 into the CaCl2 melt, and it precipitated as the lower Ti oxides. When TiCl4 gas was blown to the molten CaCl2, which was electrochemically decomposed into Cl2 gas at the carbon anode and Ca at the Ti cathode, TiCl4 gas was reduced to the dendritic Ti on the cathode surface. Because the electrolyzed Ca reacted preferentially with the oxide crucibles, most of the oxygen ions combined with Ti(II) and Ti(III), and they formed TiO and Ti2O3