Aluminum

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Aircraft fuselages and aluminium foil are just two of the many and varied uses of this element

Fact Box

Density 2.70
Melting Point 660.323°C
Boiling Point 2519°C

Uses

Aluminium is used in a huge variety of products including cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is because of its particular properties. It has low density, is non-toxic, has a high thermal conductivity, has excellent corrosion resistance and can be easily cast, machined and formed. It is also non-magnetic and non-sparking. It is the second most malleable metal and the sixth most ductile.

It is often used as an alloy because aluminium itself is not particularly strong. Alloys with copper, manganese, magnesium and silicon are lightweight but strong. They are very important in the construction of aeroplanes and other forms of transport.

Aluminium is a good electrical conductor and is often used in electrical transmission lines. It is cheaper than copper and weight for weight is almost twice as good a conductor.

When evaporated in a vacuum, aluminium forms a highly reflective coating for both light and heat. It does not deteriorate, like a silver coating would. These aluminium coatings have many uses, including telescope mirrors, decorative paper, packages and toys.

History

The analysis of a curious metal ornament found in the tomb of Chou-Chu, a military leader in 3rd century China, turned out to be 85% aluminium. How it was produced remains a mystery. By the end of the 1700s, aluminium oxide was known to contain a metal, but it defeated all attempts to extract it. Humphry Davy had used electric current to extract sodium and potassium from their so-called ‘earths’ (oxides), but his method did not release aluminium in the same way. The first person to produce it was Hans Christian Oersted at Copenhagen, Denmark, in 1825, and he did it by heating aluminium chloride with potassium. Even so, his sample was impure. It fell to the German chemist Friedrich Wöhler to perfect the method in 1827, and obtain pure aluminium for the first time by using sodium instead of potassium.