Aluminium

The history of Aluminium use

Aluminium is now one of the most widely used metals, but one of the hardest to
refine due to it's reactivity with other elements. Even as late as the turn of
the century, Aluminium was considered very valuable and in turn expensive, even
more expensive than gold. In some cultures, when a function was held (for
example, a party) by wealthy people, only the most honored guests would be given
Aluminium cutlery, the others had to make do with gold or silver cutlery.

A Description of the Aluminium ore, including a list of it's contents

Pure Aluminium oxide is known as alumina (Al2O3). This is found as corundum, a
crystalline. Aluminium can also occur as cryolite (Na3AlF6). Traces of other
metal oxides in Aluminium oxide tint it to make it form stones (often precious)
for example: chronium gives a red colour to rubies, and cobalt makes the blue in
sapphires.

How Aluminium deposits are formed

Aluminium (like many other metals) is not found in it's pure form, but
associated with other elements in rocks and minerals. An aluminosilicate such as
felspar (KAlSi3O8) is the main constituent of many rocks such as granite, which
is quartz and mica cemented together with felspar. These rocks are gradually
weathered and broken down by the action of carbon-dioxide from the air dissolved
in rainwater forming ‘kaolin'. This is further broken down to form other
substances, ultimately resulting in the formation of Aluminium deposits.

Where and how Aluminium is mined?

Aluminium is never found in it's pure state until it has been refined. Aluminium
is made when refining alumina, which is in turn found from the ore ‘bauxite'.
Bauxite is often mined in the opencast method.

Aluminium deposits are found in many countries, but the countries with
significant deposits include: Guinea, Jamaica, Surinam, Australia and Russia.

How is Aluminium refined?

One method is the ‘electrolytic process'. This is performed when a low voltage
current is passes through a bath containing alumina in the molten form. The
alumina is broken down into Aluminium metal which collects at the bottom of the
bath at one electrical pole, the cathode, and the oxygen which reacts at the
other pole, the anode, to give carbon-dioxide and some carbon-monoxide.

The uses and properties of Aluminium

Aluminium is now the second most widely used metal, after iron. Aluminium and
it's alloys, such as ‘duralumin', are used as structural metals for a wide
variety of products from aircraft to cooking utensils. Aluminium foil is used to
wrap food and is also being used to replace copper wire in electrical windings.
Aluminium mirrors are used in some large astronomical telescopes. Some Aluminium
ores are found in the form of gems and precious stones. Aluminium is also used
in the making of vehicles such as aircraft due to it's strength and light weight,
but is not used so much in cars due to it's cost.