A concept for calciothermic direct reduction of titanium dioxide in molten
CaCl2 is proposed and experimentally tested. This production process
consists of a single cell, where both the thermochemical reaction of
calciothermic reduction and the electrochemical reaction for recovery of the
reducing agent, Ca, coexist in the same molten CaCl2 bath. A few mol
pct of Ca dissolve in the melt, which gives the media a strong reducing power.
Using a carbon anode and a Ti basket-type cathode in which anatase-type
TiO2 powder was filled, metallic titanium sponge containing 2000 ppm
oxygen was produced after 10.8 ks at 1173 K in the CaCl2 bath. The
optimum concentration of CaO in the molten CaCl2 was 0.5-1 mol pct to
shorten the operating time and to achieve lower oxygen content in Ti.