Aluminium – metal of the third millenium
After iron, aluminium is now the second most widely used metal in the world. Thanks to its unique combination of attractive properties, aluminium can be a substitute for metals such as steel and copper.
Aluminium is a relatively newly discovered metal. Its increasing application has been recorded after World War II and caused literally an aluminium revolution in past 30 years. The output of primary aluminium totalled 14.1 million tonnes in 1978 and the estimated output for 2008 would exceed 44 million tonnes, while the output is expected to achieve limit of 76 million tonnes in 2017. Based on these estimations, aluminium receives an attribution „metal of the third millennium“. Aluminium is not only the third most abundant element on earth it is also a part of our daily lives, often without recognizing this fact. Its applications can be found in almost all industrial sectors – remarkable growth rates have been experienced in transport industry, especially in automotive and aviation sectors and also in building and electric engineering industries.
Aluminium - history
1807 - 1825 - 1845
The first experiments with an unknown metal date back to 1807 and they are connected with the name of Humphry Davy. This English chemist first named the metal „alumium“, which was later renamed by scientists to „aluminium“ to be consistent with other metals. Humphry Davy tried unsuccessfully to produce aluminium by electrolysing a fused mixture of aluminium oxide and potash.
Following Davy's work the Danish physicist H.C. Oersted managed to produce the first nodules of aluminium by reacting potassium amalgam with anhydrous aluminium chloride. Two years later, the German scientist Friedrich Wöhler managed to obtain aluminium in powder form by heating mixture of metallic potassium and aluminium chloride.
1854
Frenchman Henri Sainte-Claire Deville devised a method by which the metal could be prepared on a large scale by the aid of sodium. The purity of aluminium obtained was 92% and the main impurities included Si and Fe elements.
1886
Two scientists (Poul Lois Toussaint Heroult in France and Charles Martin Hall in the USA) almost simultaneously but independently filed patents for method of manufacturing aluminium by the electrolysis of aluminium oxide dissolved in molten cryolite.
1888
The success of the Hall/Heroult process was advanced by Austrian chemist Karl Bayer who improved the process for extraction of aluminium oxide from bauxite.
The currently applied industrial process for the production of aluminium by the electrolysis of aluminium oxide dissolved in molten only slightly differs from the Hall/Heroult process. However, the process involves a series of issues causing low energy gain in spite of various improvements made to the process during its over 110 year history. Another concern is associated with the demanding production of aluminium oxide from bauxite. The bauxite deposits are limited to certain regions. The largest deposits of bauxite occur in tropical areas with the primary mining areas located in Australia, Brazil and Jamaica.