Mechanism of titanium sponge formation in the kroll reduction reactor

The Kroll process of magnesium reduction of titanium tetrachloride is used the world over the production of titanium metal in the form of sponge. Although the process has been in practice for the last five decades, there is no clear understanding of the reaction mechanism and sponge formation. The present study involved reduction experiments in a 2000 kg titanium sponge-capacity prototype reactor to develop a better understanding of TiCl4 reduction of magnesium with respect to the process parameters. Experiments were also conducted in two smaller experimental reactors to study the temperature evolution during the process as a function of the TiCl4 feed rate. Based on the results of all these experiments, a model has been proposed for the mechanism of sponge formation in the Kroll process.