Aluminium

Aluminium is a silvery ductile metallic element found primarily in bauxite. It is member of the Boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances. Aluminium is the most abundant metal in the Earth's crust, and the third most abundant element therein, after oxygen and silicon. It makes up about 8% by weight of the Earth's solid surface. Aluminium is too reactive chemically to occur in nature as a free metal. Instead, it is found combined in over 270 different minerals chiefly bauxite ore. Aluminium is a good thermal and electrical conductor, having 62% the conductivity of copper. Aluminium is capable of being a superconductor, with a superconducting critical temperature of 1.2 kelvins and a critical magnetic field of about 100 gauss (10 milliteslas).

History

Aluminium dates back to the ancient Roman and Greek time period. They used Aluminium salts as dyeing mordants and as astringents for dressing wounds. In 1761 Guyton de Morveau suggested calling the base alum alumine. In 1808, Humphry Davy identified the existence of a metal base of alum, which he at first termed alumium and later aluminium.

In 1825, the metal was first produced in an impure form during 1825, by Danish physicist and chemist Hans Christian Ørsted. He reacted anhydrous aluminium chloride with potassium amalgam and yielded a lump of metal looking similar to tin. Another chemist from Germany, Friedrich Wöhler repeated the experiments of Ørsted and concluded that this metal was pure potassium. He conducted a similar experiment in 1827 by mixing anhydrous aluminium chloride with potassium and yielded aluminium. Wöhler is generally credited with isolating aluminium.

Development in the Discovery of Aluminium

In 1846, Pierre Berthier discovered aluminium in bauxite ore and successfully extracted it. Frenchman, Henri Etienne Sainte-Claire Deville improved Wöhler's method in 1846, and described his improvements in a book in 1859, chief among these being the substitution of sodium for the considerably more expensive potassium. Deville likely also conceived the idea of the electrolysis of aluminium oxide dissolved in cryolite.

Charles Martin Hall of Ohio in the U.S. and Paul Héroult of France independently developed the Hall-Héroult electrolytic process that made extracting aluminium from minerals cheaper and is now the principal method used worldwide. The Hall-Heroult process cannot produce Super Purity Aluminium directly. Hall's process, in 1888 with the financial backing of Alfred E. Hunt, started the Pittsburgh Reduction Company today known as Alcoa. Charles Martin Hall's method of processing the metal ore was to pass an electric current through a non-metallic conductor (molten sodium fluoride compound was used) to separate the very conductive aluminum. In 1889, Charles Martin Hull was awarded U.S. patent #400,666 for his process. By 1914, Charles Martin Hall had brought the cost of aluminium down to 18 cents a pound and it was no longer considered a precious metal.

Role of the Discovery of Aluminium in the development of Human Life

• Because of it's properties in was used in the manufacture of automobiles, aircraft, trucks, railway cars, marine vessels, bicycles  etc.) as sheet, tube, castings etc.

• Aluminum also found it's usage in a wide range of household items, from cooking utensils to baseball bats, watches.

• Aluminium alloys form vital components of aircraft  and rockets  as a result of their high strength-to-weight ratio. Aluminium readily forms alloys with many elements such as copper, zinc, magnesium, manganese and silicon, e.g. Duralumin.