Aluminium makes up approximately 8% of the Earth’s crust and therefore is aluminum one of the most common elements. New aluminium is extracted from bauxite, a mineral quarried from open cast mines that litter the area around the equator or in Australia. Bauxite is a sedimentary rock formed by the weathering of silicate material in tropical conditions. It is composed, to a greater or lesser degree, of hydrated oxides of aluminium, iron and titanium.
The bauxite is crystallized in a refinery into alumina powder (alumina) which is then transported to an aluminum smelter, usually via container ships and this is done according to the Bayer method.
An aluminum smelter is very energy intensive and is thus often placed where there is good access to electricity. In the smelter, the alumina powder is converted to aluminum through a process called electrolysis. The process is started by immersing carbon anodes in liquid alumina powder where large amounts of electricity are drawn through the cell.
Primary aluminium has a purity of at least 99.5%. Producers then add a variety of alloying materials to produce a range of aluminium alloys.
Aluminium extrusions are used in many different industries. In the construction industry, for example, they are used in windows, doors, doorways and balconies, thanks to their corrosion resistance and low weight. Its high level of durability is also a contributing factor in aluminium being a widely used material in load-bearing structures in aircraft. In addition, aluminium’s heat conducting characteristics are exploited in cooling extrusions.
Aluminium is increasingly used in the automotive industry, not least because of its light weight, which means fuel savings can be achieved throughout the life of a vehicle. Reducing the weight of lorries, buses and trains increases their carrying capacity, while lighter vehicles reduce the risk of injuries in case of accidents. The low weight and low maintenance need also help to build more and more ships in aluminum.
In the electronics and telecom industry, profiles are used, among other things, in base stations, antenna mounts and front panels. Low weight and good opportunities to incorporate many functions are natural explanations for the use of aluminum profiles in components for the telecom industry.
One kilogram of aluminum can transmit twice as much electricity as one kilogram of copper. Therefore, aluminum has largely replaced copper in, for example, high voltage lines.
Aluminium has a density of 2.7 kilograms per cubic metre. Iron is approximately three times heavier. Aluminium has a high conductivity for both electricity and heat, approximately 60% compared to electrolytic copper. If brought into contact with atmospheric oxygen, aluminium forms a protective oxide layer. If the layer is damaged, it simply re-forms.
Aluminium alloys have breaking strengths of between 70 and 700 Mpa. In addition, aluminium also maintains its ductility at temperatures down to -200 degrees and has a relatively large linear expansion coefficient.
