Behavior of zirconium sponge formation in the Kroll process

The Kroll process of magnesium reduction of titanium tetrachloride is used for mass production of zirconium sponges. This study is conducted in a laboratory-scale reactor in order to develop a better understanding of the zirconium sponge formation mechanism in the Kroll reactor with respect to the reaction degrees and reaction time. The MgCl₂ produced during the initial stage of the reaction does not sink into the molten magnesium, but remains on the surface of the molten magnesium. As a result, ZrCl₄ feed reacts with the Mg exposed on the edge of the molten MgCl₂ in the crucible. Therefore, the Zr particles produced at the later reaction stage descend into the molten magnesium at the crucible wall.