How is chlorine used to extract titanium from titanium-containing materials?

Chlorine is essential in the industrial extraction of titanium through a process known as carbo-chlorination, which converts titanium-containing ores into titanium tetrachloride (${\text{TiCl}}_4$).12

The process involves the following steps:

• Chlorination: Titanium-bearing ores (such as rutile or ilmenite) are reacted with chlorine in a fluidized bed of petroleum coke at high temperatures, typically between 850 and 1,000 °C. During this reaction, carbon from the coke combines with oxygen to form carbon monoxide and carbon dioxide, while the titanium reacts with chlorine to produce gaseous ${\text{TiCl}}_4$.12
• Purification: The resulting raw ${\text{TiCl}}_4$ is liquified and subjected to fractional distillation to remove impurities, such as ferric chloride and vanadium oxychloride, ensuring a purity level exceeding 99.9 percent.12
• Reduction: In the Kroll process, the purified ${\text{TiCl}}_4$ is reduced using molten magnesium in an argon atmosphere at approximately 800 °C. This reaction yields metallic titanium as a spongy mass, from which excess magnesium and magnesium chloride are removed through volatilization.2

This method is necessary because titanium is highly reactive at elevated temperatures, making traditional reduction with carbon impractical.2