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Aluminum is one of the most abundant element on earth, and its oxide is present in clay, kaolin and many other mineral formations. For economic reasons, aluminum is almost exclusively produced from bauxite, which is a residual clay formed in tropical regions by the chemical weathering of basic igneous rocks. It contains 55 to 65% aluminum oxide (alumina) together with varying amounts of iron oxide, silica and titanium oxide.

Ancient Greeks and Romans used aluminium salts as dyeing mordants and as astringents for dressing wounds; alum is still used as a styptic. 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 aluminum.

Friedrich Wöhler is generally credited with isolating aluminium (Latin alumen, alum) in 1827 by mixing anhydrous aluminium chloride with potassium. As the metal had first been produced two years earlier by Danish physicist and chemist Hans Christian can also be listed as its discoverer. Further, 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.

Aluminium is a soft, durable, lightweight, malleable metal with appearance ranging from silvery to dull gray, depending on the surface roughness. Aluminium is nontoxic, nonmagnetic, and nonsparking. It is also insoluble in alcohol, though it can be soluble in water in certain forms. The yield strength of pure aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminum has about one-third the density and stiffness of steel. It is ductile, easily machined, cast, and extruded.

It is often said that Aluminum has had a relatively brief history, and under the name Aluminum it is certainly true. But using aluminum for its properties in compounds (some sources reckon) started at around 5300 BC. It is thought that potters in ancient Persia made their strongest cooking vessels from a clay that consisted largely of aluminum silicates. Aluminum compounds are thought to have been used more by the Egyptians and Babylonians around 4000 years ago as fabric dyes and cosmetics.

Despite these uses in the very far past the element aluminum itself wasn't discovered or named until the early 1800's when Sir Humphrey Davy established its existence, but even he was unable to actually make any. Just over 10 years later a French scientist discovered hard, red clay containing over 50% aluminum oxide in southern France. It was named bauxite, aluminum's most common ore. As aluminum is so combined in nature, and never occurs naturally, even up to this time no pure aluminum had been produced.

The basic method for making aluminum oxide from bauxite is the Bayer process (Fig.1). The bauxite is dried, ground and treated with caustic soda solution in an autoclave. As a result, the aluminum is dissolved as sodium aluminate (NaAlO2), while iron oxide, titanium oxide and silica remain undissolved in the residue (known as red mud). The solution is filtered, and the aluminum is precipitated from it as aluminum hydroxide Al(OH)3, which is separated by filtration and then calcined to aluminum oxide in a rotary kiln.

The purified aluminum oxide is dissolved in molten cryolite; a sodium-aluminum fluoride (Na3AlF6) and electrolyzed with direct current. This is done in an electrolytic cell (Fig.2), which is essentially a tank lined with carbon bricks and provided with carbon anodes. The carbon lining forms the negative pole (cathode). Under the influence of the electric current the oxygen of the Al2O3 is deposited on the anodes, while the molten aluminum is deposited on the lining.

The metal accumulates at the bottom of the cell. More aluminum oxide is stirred into the electrolyte from time to time and the molten metal is removed. Currents of very high intensity are used i.e. up to 100,000 amps. at 5 or 6 volts. A cell may be 20ft. long 6ft wide and 3ft deep. A modern processing plant may comprise a large number of such cells. The ordinary commercial aluminum obtained in this process may be up to 99.9% pure, which is sufficient for most purposes. In some cases, however, it is necessary to increase the purity by refining.

In present day use, three layer-electrolysis is the refining method is carried out in a cell provided with a carbon lined bottom and magnesite-lined walls. In this type of cell the carbon bottom forms the anode, while a graphite electrode forms the cathode. To increase its specific gravity, the aluminum to be refined is first alloyed with copper or some other metal and is introduced into the cell in the molten condition.

Over it is a layer of molten salt which is specifically lighter than this alloy, but heavier than pure aluminum. The passage of an electric current causes pure aluminum to go to the cathode with the result that it accumulates as a layer floating on the molten salt. This aluminum, which has a purity of 99.99% is removed from time to time and cast into suitable shapes for commercial purposes.