Aluminium is the world’s most recently discovered metal in common use, yet it had practical applications long before it was officially “discovered”. Ancient civilizations dating back to 5300 BC used aluminium-bearing clays to make pottery, and aluminium salts to make dyes and medicines. However, the "metal of clay", as it was known in ancient times, remained locked in the elements of the earth for thousands of years. It wasn’t until 1808 that Britain’s Sir Humphrey Davy established the existence of aluminium and named it, without succeeding in actually producing any. What followed was a long and painstaking process to unlock the secrets of the metal, which never occurs in its pure form in nature, but exists only in combination with other materials – silicates and oxides. In 1825, H.C. Oersted produced the first small lump of aluminium in Denmark. Twenty years later, Friedrich Wohler in Berlin was still only able to produce aluminium "as big as pin heads". Finally, in 1854, a French chemist named Henri Sainte-Claire Deville created the first commercial process and, with the assistance of Emperor Napoleon III, opened the world's first aluminium factory in 1859 at Glaciere near Paris. The aluminium produced by this method was more expensive than gold or platinum. In 1885, a U.S. scientist named Hamilton Y. Cassner enhanced Deville’s process. The result of this “improvement” was an annual output of only 15 tons. It wasn’t until 1886 that two unknown scientists – Charles Martin Hall of the U.S., and Paul L.T. Heroult of Gentilly, France – unaware of each other’s work, discovered within a month of each other that if they dissolved aluminium oxide (alumina) in a bath of molten cryolite and passed a powerful electric current through it, molten aluminium would be deposited at the bottom of the bath. This electrolytic process, dubbed the Hall-Héroult process, is still the basis for all aluminium production throughout the world today. Technological advances in production and pollution control techniques have considerably improved it, however, so that a modern aluminium smelter provides a clean, efficient and safe work environment at a low unit cost. FromBauxitetoFlight Aluminium is a metallic element that comes from the ore bauxite, which gets its name from Les Baux, France, where it was discovered in 1821. Today, bauxite is predominantly found in tropical and sub-tropical regions. The ore (shown at right) is found in strata or “pockets”, typically about 12 meters thick under a shallow covering of topsoil and vegetation. Because of its proximity to the surface, bauxite is quite easy and environmentally friendly to mine. It is generally extracted using open cast mining: the topsoil is taken away and vegetation samples carefully preserved. After the bauxite is removed, the soil and vegetation are replaced. Two to three tons of bauxite is required to make one ton of alumina, depending on the grade of the bauxite. While the mining process is relatively simple, the process to extract the aluminium from the bauxite is quite complex. There are two successive stages: first, a chemical process extracts alumina or anhydrous aluminium oxide from the bauxite, followed by the Hall-Héroult electrolytic process to reduce the alumina to aluminium. While aluminium is sometimes used in its commercially pure form, most applications involve the addition of small quantities of other metals to create alloys with special properties. Certain alloying elements will increase strength or corrosion resistance, while others enhance specific properties, such as machinability, ductility, weldability and strength at high temperature. Regardless of the alloy, the aluminium content is usually above 90 per cent. For example, recyclable aluminium beverage cans are made from an alloy containing manganese that provides strength and formability, while magnesium is added to create an alloy with the added strength required for the can top. Aircraft components are made from high-strength alloys containing copper, magnesium, silicon and zinc. The aerospace industry employs the new aluminium-lithium alloys which provide significant weight savings over other alloys of similar strength.

AluminiumFastFacts Industry Overview Aluminium is the earth’s most abundant metallic element, making up approximately eight per cent of the planet’s crust. Aluminium has only been produced commercially for 144 years, yet it has overtaken its long-time predecessors, copper, lead and tin, not only in volumetric terms but even in tonnage terms – an impressive feat considering its light weight. The U.S. total aluminium supply was 24.1 billion pounds in 1999, an increase of five per cent over the previous year. According to the Bureau of Census, during 1997, the U.S. aluminium industry employed almost 144,000 people with a total value of industry shipments estimated at about $39.1 billion. Properties & Benefits Aluminium is three times lighter than steel, but when alloyed, can attain steel’s high-strength characteristics. Aluminium is corrosion-resistant, making it hygienic and long-lasting. One pound of aluminium has more than twice the electrical conductivity of an equal weight of copper. Recycling (all figures are based on U.S. statistics) Since the chemical composition of aluminium remains unchanged during remelting, it is easily and efficiently recycled. Recycling accounts for 33 per cent of total aluminium supply. Remelting of aluminium scrap requires only five per cent of the energy needed to produce primary aluminium. 63.9 billion aluminium beverage cans were recycled in 1999 – about 1.9 billion pounds of aluminium compared to only 103 million pounds in 1974. Recycling accounts for 62.5 per cent of total can shipments, and 33 per cent of total supply. Aluminium beverage cans make up about 100 per cent of the total beverage can market, compared to only 20 per cent in 1974. Processes No other metal can undergo such a wide variety of processes or be fashioned into such a myriad of shapes as aluminium. Casting: Pouring molten metal into moulds. Forging: Hot metal is hammered or squeezed into the shape of a die, used extensively in highly stressed structural parts. Drawing or Pressing: Forcing a flat metal blank into a die under pressure from a metal ram, mainly used to manufacture 'hollowware'. Extruding: Pushing the aluminium through a die to form longer tube, rod, or wire products. Rolling: Squeezing the aluminium between two rollers to form a flat plate sheet or foil product at very fine gauges (as thin as .0006mm). Spinning: A circular metal blank is rotated at high speed and pushed into the shape required by the pressure from a tool. For more information, see our On-line Aluminium Glossary.

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