Production

Primary and secondary aluminium

Aluminium is the most common metal in the Earth's crust. It makes up approx. 8% of the crust. Aluminium only occurs naturally in a chemical bond with oxygen (and other elements) and is very hard to separate from that bond. This means it was discovered relatively late. It was first produced by Friedrich Wöhler in 1827 in a laboratory at a vocational school in Berlin.

Producing aluminium

Primary and secondary aluminium are different.

1. Primary aluminium

Aluminium is obtained from bauxite, named after the area where it was discovered (Les Baux). Bauxite usually consists of up to 60% alumina, iron oxide and silica. Main sources: South America, Australia and Africa

  1. Preparing bauxite: Raw bauxite is crushed, dried and milled finely.
  2. Obtaining alumina from bauxite: Non-desirable elements are removed by using caustic soda. This leaves you with pure, white alumina (aluminium oxide).
  3. Reducing alumina to aluminium via electrolysis: Alumina is dissolved in melted cryolite at approx. 950°C. This solution is broken down into its elements with direct current in an electrolysis kiln. The aluminium collects at the bottom and the released oxygen combines with the carbon electrodes to form carbon dioxide.

You can obtain 2 t of alumina from 4 t bauxite - resulting in 1 t of aluminium.

2. Secondary aluminium

Secondary aluminium consists of recycled aluminium and is regained via the circulation of scrap. The effort required for recycling is approx. 5% of the effort required to produce primary aluminium.

Aluminium and the environment

When producing aluminium for PREFA products, approx. 10% primary aluminium and approx. 90% secondary aluminium is used. This means aluminium is almost 100% recyclable with no significant loss of quality! Given its longevity, lack of maintenance required, excellent recycling capacity and low weight (transport), aluminium achieves an extremely positive eco-balance.



Surfaces/colour quality

Surfaces/colour quality

Properties:

  • Melting point: 660°C
  • Density: 2.7 kg/dm³
  • Tensile strength approx. 100-190 N/mm²
  • Excellent heat and electricity conductor
  • Excellent heat reflector
  • Highly resistant to weathering influences (does not rust)
  • Aluminium is non-toxic
  • Recyclable


Thanks to its extremely low weight and resistance, aluminium is the ideal material for many high-tech areas of application
(plane construction, automotive industry, construction industry, furniture, etc. )