CHEMICAL DEFINITION
|
|
Aluminium: a chemical element (symbol Al) with an atomic number of 13, an atomic weight of 26.98, and a single stable isotope: 27.
Aluminium is a soft, silvery metal.
Relative density: 2.70
Melting point: 660°C
A thin, waterproof layer of aluminium oxide is formed on contact with the air.
Aluminium is a very important construction material in combination with other metals. The major compounds of aluminium are the oxide, hydroxide, chloride, sulphate, silicate, and acetate.
(Source: Encarta)
|
ORIGIN
Aluminium is the third most abundant element on earth (after oxygen and silicon). An estimated 8% of the earth’s crust consists of aluminium.
The highest concentration of aluminium is found in bauxite (45-60%).
Bauxite was first discovered in Les Baux, a town in southern France, hence the name bauxite.
THE HISTORY OF ALUMINIUM
In 2011, Aluminium celibrates its 125th anniversary !
- In 1761, a Frenchman named de Morveau discovered a previously unknown material. He gave it the name ‘alumina’, from the Latin word ‘alumen’, which means ‘light’.
- In 1787, the chemist Lavoisier determined that alumina was an oxide of a metal that was unknown at that time.
- In 1821, bauxite was discovered at Les Baux.
- In 1825, the chemist Oersted isolated the metal for the first time in a more or less pure state by using a complex distillation method.
In the following years, Wöhler (1827) and Deville (1854) searched for less expensive ways to produce aluminium.
- In 1855, an aluminium rod produced by Deville was exhibited next to a silver rod at the World Exhibition in Paris. The response to the new metal was enthusiastic.
- In 1865, the author Jules Verne suggested that space travel would one day become reality thanks to aluminium.
- In 1866, Charles Martin Hall and Paul Héroult developed a method for extracting aluminium from alumina by using electrolysis.
- In 1898, the Bayer process was developed. This made it possible to produce alumina powder from bauxite on a large scale. On the eve of the 20th century, aluminium was poised to acquire the status of a basic material for the production of all sorts of new and modern products. (Source: EOS)
ABOUT THE METAL
In terms of its physical, chemical and mechanical properties, aluminium is a metal, just as steel, brass, copper, zinc, lead and titanium are metals.
It can be melted, cast, shaped and worked in roughly the same way as these metals and it conducts electricity.
MARKETS
The principal markets for aluminium producers are in the transportation, construction and packaging sectors.
Other markets include electrical and electronic engineering, machine construction, office furnishings, household appliances, lighting and chemical and pharmaceutical products.
(Source: www.eaa.net)
ALLOYS
Aluminium can be alloyed with manganese, silicon, magnesium, zinc and other elements. The addition of a small amount (0.5-3%) of one or more other metals is sufficient to enhance certain useful properties of aluminium, such as strength, hardness, weldability or corrosion resistance.
SURFACE TREATMENT
A thin, matt grey oxide layer forms on the surface of ‘natural’ aluminium due to a natural reaction with oxygen in the air. It protects aluminium products against corrosion and causes aluminium to last longer than other construction materials under comparable conditions.
The following methods can be used to provide additional protection or for aesthetic reasons:
Anodizing
This is an electrochemical process that artificially increases the thickness of the oxide layer on the aluminium from 0.1 µm to 15 or 30 µm. Anodized finishing can be produced in various colours.
For more information on anodising, click on Facilities - Anodizing
Powder coating
The coating is sprayed in powder form onto the pre-treated aluminium surface with the aid of static electricity. After the coating is applied, it is dried and cured in an oven. Coatings can be applied in any desired colour and with various thicknesses.
For more information about this treatment, click on Facilities- Powder Coating