Aluminium and titanium

Block of aluminium metal

Aluminium and titanium are two metals with a low density. This means that they are lightweight for their size. They also have a very thin layer of their oxides on the surface, which stops air and water getting to the metal, so aluminium and titanium resist corrosion. These properties make the two metals very useful.

Aluminium is used for aircraft, trains, overhead power cables, saucepans and cooking foil. Titanium is used for fighter aircraft, artificial hip joints and pipes in nuclear power stations.

Extraction

Unlike iron, aluminium and titanium cannot be extracted from their oxides by reduction with carbon:

• Aluminium is more reactive than carbon, so the reaction does not work.
• Titanium forms titanium carbide with carbon, which makes the metal brittle.

Aluminium extraction is expensive because the process needs a lot of electrical energy. Titanium extraction is expensive because the process involves several stages and a lot of energy. This especially limits the uses of titanium.

Recycling

Aluminium is extensively recycled because less energy is needed to produce recycled aluminium than to extract aluminium from its ore. Recycling preserves limited resources and requires less energy, so it causes less damage to the environment.