How titanium is made

You cannot smelt titanium like iron, because it grabs carbon and oxygen so eagerly that the usual route ruins it.

stations: 5
things upstream: 16
raw sources: 9
steps from the ground: 4

The short version

Titanium ore is turned into titanium tetrachloride, a liquid, by passing chlorine over a hot mixture of ore and carbon. After distilling it clean, makers reduce it with molten magnesium in argon at about 800 °C in the Kroll process. The porous sponge of metal is then melted under vacuum or inert gas and worked into mill products.

Chlorinate the ore

Chlorine gas is passed over a red-hot mix of rutile or ilmenite and carbon. The titanium comes out combined with chlorine as titanium tetrachloride, a colorless volatile liquid. Heating the ore with carbon alone would produce titanium carbide.

Goes in
Titanium ore Chlorine
Distill it clean

The crude tetrachloride is purified by fractional distillation. It reacts readily with trace water, so everything downstream must be kept dry.
Reduce it with magnesium

In the Kroll process, the purified liquid meets molten magnesium in a reactor filled with argon. The magnesium takes the chlorine, and titanium is left behind as a porous sponge. It is a batch process, which is why titanium stays so costly.

about 800 °C

Goes in
Magnesium Argon
Melt the sponge into ingot

Titanium burns in normal air at temperatures below its melting point of 1,668 °C, so melting must be done in a vacuum or inert atmosphere. Sponge, sometimes with a master alloy, is melted into an ingot.
Forge into mill products

The ingot is turned into billet, bar, plate, sheet, strip and tube. Heating titanium in air during forging can leave a brittle, oxygen-rich skin, so shops take care with the atmosphere.

End of the lineTitanium Next it goes into pacemaker, hip implant, airliner and 3 more.

Worth repeating

Titanium forms a protective oxide skin 1 to 2 nanometers thick as soon as it meets air.
William Gregor discovered titanium in 1791 in black sand from a stream in Cornwall.
The Kroll process also drives most of the world's production of magnesium metal.