A new cell concept for calciothermic reduction is proposed that titanium dioxide instead of TiCl4 is used as the raw material for reduction. Metallic calcium is needed as the reductant of the thermochemically stable oxide such as TiO2. CaCl2 is selected as the solvent of Ca, and simultaneously as the solvent of CaO.
The reduction system consists in a single cell, where both the reduction reaction and the electrolytic reaction for recovery of reducing agent coexist in the same molten CaCl2 bath. A few mol%Ca dissolves in the melt, and it makes the media with a strong reducing power. Sufficiently deoxidized titanium metal deposits and forms a slightly sintered granular sponge. Both mechanisms of the halide flux deoxidation and the electrochemical deoxidation work efficiently for these fine precipitates. The reducing agent is in situ recovered by electrolysis of CaO because the molten CaCl2 has a relatively large solubility for CaO. Some cell designs and modifications are proposed for industrial applications.