How is aluminium produced?
Aluminium does not appear in pure form in nature. The earth’s crust does consist of 8.5% aluminium compounds including other elements. The highest concentrations of aluminium can be found in the bauxite ore, which is mined in Australia, Latin America and Africa, among others. How is aluminium extracted? In order to produce 1 kg of pure aluminium, approx. 4.6 kg of bauxite are required. Alumina (1.9 kg) is extracted from the bauxite. The residue (2.7 kg), referred to as “red mud” can be partially used as artificial fertiliser, filling material for asphalt roads, the colouring of roof tiles, water purification, etc. The alumina is electrolytically reduced in a bath, from which new, liquid aluminium is poured into various moulds (mould ingots, tee ingots, rectangular slabs or extrusion billets). The production process requires a lot of energy, of which 65% is generated by hydro-electric power stations. From slab to profile Castings such as handles or floor grills are made from “ingots”. T
