Aluminium Bauxite
Aluminium is found in the form of oxides and never occurs naturally
in its pure form. is earth's most abundant metallic element, making up
approximately eight per cent of the planet's crust.
If we continue to mine Bauxite at the present rate the deposits will
last 200- 400 years (this does not include any increase in recycling).
Bauxite is predominantly found in tropical and sub-tropical regions of
the world is the most commercially viable source of Aluminium. It can
be found as rocks or granules and, depending on its exact composition,
it can also vary in colour.
Bauxite is a Sedimentary rock. Sedimentary rocks are derived from decomposed
or weathered older rocks which are transported by water, ice or wind
to some other place and deposited there. Bauxite is a Chemical Sediment,
which means that it is formed from substances dissolved in water which
have precipitated, either due to evaporation or to a change in the chemical
composition of the solution.
The ore occurs near the surface (usually less than 100 feet), which
makes the deposits suitable for mining by simple open-cast methods. No
drilling or blasting is generally required because of the soft, earthy
nature of the ore.
Deposits may be located in areas varying from gentle undulating to rugged,
hilly terrain involving major capital expenditures in creating a system
to transport the ore.
Even though the ore is generally easy to mine, the process to extract
the Aluminium from it is very complex.
The process of making metallic Aluminium is carried out in two successive
stages:
The chemical process to extract anhydrous Aluminium oxide or alumina
(A12O3) from the ore.
The electrolytic process to reduce the alumina to Aluminium
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