Preparation methods of titanium

Smelting titanium involves a complex process. Ilmenite is converted into titanium tetrachloride, which is then placed in a sealed stainless steel container filled with argon gas to react with metallic magnesium, yielding sponge titanium. Sponge titanium cannot be used directly; it must be melted into a liquid in an electric furnace before being cast into titanium ingots.

However, this type of electric furnace requires highly advanced technology. Besides the need to completely evacuate the furnace, a major challenge is the scarcity of crucibles to hold the liquid titanium, as most refractory materials contain oxides, and the oxygen in these oxides is absorbed by the liquid titanium. Eventually, a water-cooled copper crucible electric furnace was invented. In this furnace, only a central area is heated, while the rest remains cold. The molten titanium flows onto the water-cooled copper crucible walls, where it immediately solidifies into titanium ingots.

The industrial method for large-scale titanium production is the Kroll process: first, chlorine and carbon are used to react with ilmenite (TiFeO3) or rutile (TiO2) to produce metallic titanium. The obtained titanium tetrachloride (TiCl4) is then separated from ferric chloride (FeCl3) by distillation. Finally, titanium tetrachloride is reduced with metallic magnesium (Mg) to obtain metallic titanium. Air should be removed during the production process to prevent titanium from reacting with oxygen or nitrogen and generating impurities.