Why is titanium tetrachloride purified by distillation before metal production?

Titanium tetrachloride (${\text{TiCl}}_4$) is purified by distillation before metal production to ensure the final titanium product meets high-quality standards. During the extraction process, raw ${\text{TiCl}}_4$ contains various volatile impurities with both high and low boiling points, as well as entrained particles from the ore and coke used in the reaction.1

Distillation is essential because any contaminants present in the ${\text{TiCl}}_4$ would be reduced alongside the titanium during the subsequent metal production process, such as the Kroll process. By utilizing a reflux distillation column, manufacturers can remove these impurities to achieve a ${\text{TiCl}}_4$ purity level exceeding 99.9 percent. Specific impurities, such as vanadium oxychloride, which has a boiling point similar to ${\text{TiCl}}_4$, are stripped from the stream using mineral oil before the final distillation steps.12