Effect of TiCl ₄ feeding rate on the formation of titanium sponge in the kroll process

The Kroll process for magnesium reduction of titanium tetrachloride is used for mass production of titanium sponge. The present study was conducted in a lab scale reactor to develop a better understanding of the mechanism of titanium sponge formation in the Kroll reactor with respect to reaction degrees and the feeding rate of TiCl ₄. The MgCl ₂ produced during the initial stage of the reaction was not sunk into the molten magnesium, but covered the surface of the molten magnesium. As a result, subsequently fed TiCl ₄ reacted with Mg exposed on the edge of molten MgCl ₂ in the crucible. Therefore, titanium sponge grew toward the center of the crucible from the edge. The temperature of the molten magnesium increased remarkably with the increasing feeding rate of TiCl ₄. Consequently, fed TiCl ₄ reacted at the upper side of the crucible with evaporated Mg, and produced titanium on the upper surface of the crucible wall, which increased considerably with the feeding rate of TiCl ₄.