Production

The metal itself has only been known about 130years,and the industrial history of aluminium did not begin until 1886 when Paul Heroult in France discovered the basis of the present-day method of producing aluminium. Aluminium is now produced in such quantities that in terms of volume it ranks second to steel among the industrial metals. Aluminium of commercial purity contains at least 99 per cent aluminium,while higher grades contain 99.5–99.8 per cent of pure metal.
In the production of aluminium,the ore bauxite is crushed and screened,then washed and pumped under pressure into tanks and filtered into rotating drums,which are then heated. This separates the aluminium oxide from the ore. In the next stage the aluminium oxide is reduced to the metal aluminium by means of an electrolytic reduction cell. This cell uses powdered cryolite and a very heavy current of electricity to reduce the aluminium oxide to liquid metal,which passes to the bottom of the cell and is tapped off into pigs of aluminium of about 225kg each.