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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