Production of aluminium
Aluminium is produced from the raw material bauxite. Bauxite is crushed and ground into a powder from which aluminium oxide is extracted using lye and lime. Primary aluminium can then be produced by smelting electrolysis and solidified into ingots or ingots.
Aluminium goes through various processes to become a finished product. This can be, for example, rolling to make sheet metal, casting to create desired shapes or extrusion to create profiles and bars.
During the process, different types of alloying elements are usually added to give the aluminium specific properties suitable for the intended use. Examples of such additives are silicon and magnesium. Read more about aluminium alloys here.
Aluminium is produced from the raw material bauxite
Bauxite is a raw material and sedimentary rock consisting of 50-65 % alumina, which is equivalent to 25-30 % pure aluminium. Bauxite is a mixture of several minerals and is usually reddish-brown in colour and similar to clay. The rock often occurs 5-10 metres below ground level, and is mined across much of the world, with Australia accounting for the largest occurrence. Its primary use is for the production of aluminium. However, there are no bauxite deposits in Sweden, and there is generally limited mining of bauxite in the EU.
Bauxite and environmental impact
Bauxite has a high melting point and therefore requires large amounts of energy to produce aluminium. Mining also has an impact on the environment and can be detrimental to the area where it takes place if not carried out properly. However, aluminium can be recycled without losing its properties, and much of the aluminium ever produced is still in use today.
At Interal, we deal with this by carefully sorting the scrap fractions that arise during processing. Cuttings and machining chips are sorted and disposed of so that they can be melted down and reused without losing any of the material.
Extrusion of aluminium
Aluminium extrusion is a manufacturing process where aluminium ingots are formed into the desired type of profile by extrusion.
The aluminium ingot is heated to a temperature of between 450-550 degrees and then pressed through a tool (die) consisting of one or two parts depending on whether it is to become a solid or hollow profile. The aluminium profile is then cooled with air or water, stretched to release any stresses in the material, and then goes through hot or cold ageing to give the material its final strength.
