How to efficiently reduce of ilmenite to pure titanium?
Ilmenite mainly consists of $\ce{TiO2}$ and iron oxides. The idealized formula of ilmenite is approximately $\ce{FeTiO3}$.

Note that the aluminothermic process would yield ferrotitanium alloys, and the reduction with carbon would yield titanium carbide.

The titanium ore can be converted to titanium tetrachloride according to
$$\ce{TiO2 + 2Cl2 + 2C -&gt; TiCl4 + 2CO}$$
or
$$\ce{2FeTiO3 + 7Cl2 + 6C -&gt; 2TiCl4 + 2FeCl3 + 6CO}$$
(If a large content of iron oxides causes problem, it can be partially removed first by partial reduction with carbon.)

Titanium tetrachloride (boiling point: 136.5 °C) can be purified by fractional distillation.

Finally, titanium tetrachloride can be reduced to titanium sponge with magnesium (Kroll process):
$$\ce{TiCl4 + 2Mg -&gt; Ti + 2MgCl2}$$

The remaining $\ce{Mg}$ and $\ce{MgCl2}$ can be removed with hydrochloric acid.