Extraction of Metals

Extraction of Titanium.

The extraction of titanium uses the Kroll process.
Titanium ore is called rutile. Rutile contains titanium dioxide - TiO₂.
Titanium dioxide is converted into titanium chloride - TiCl₄.

Titanium is more reactive than carbon but it is
not extracted by electrolysis because titanium chloride is covalent
and therefore does not conduct electricity.
Titanium chloride is a yellow liquid (melting point is -24 °C).
It is unusual for a metal to form covalent bonds.

Magnesium or sodium are used
to reduce titanium chloride to titanium metal.
This is an example of a metal displacement reaction.
The reaction is carried out in an argon atmosphere to prevent
magnesium or sodium from reacting with oxygen in the air.

magnesium + titanium chloride  magnesium chloride  + titanium.
2Mg_(l)     +     TiCl_4(l)                         2MgCl_2(l)     +     Ti_(s)

sodium + titanium chloride  sodium chloride  + titanium.
4Na_(l)     +     TiCl_4(l)                         4NaCl_(l)     +     Ti_(s)

Magnesium and sodium, both expensive metals,
are used up in the production of titanium.
Titanium is therefore more expensive than either
magnesium or sodium and has limited specialised uses.

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