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13. AluminumName: Aluminum
Pure aluminium is a silvery-white metal with many desirable characteristics. It is light, nontoxic (as the metal), nonmagnetic and nonsparking. It is somewhat decorative. It is easily formed, machined, and cast. Pure aluminium is soft and lacks strength, but alloys with small amounts of copper, magnesium, silicon, manganese, and other elements have very useful properties. Aluminium is an abundant element in the earth's crust, but it is not found free in nature. The Bayer process is used to refine aluminium from bauxite, an aluminium ore. The oldest suspected (although unprovable) reference to aluminium is in Pliny the Elder's Naturalis Historia. Ancient Greeks and Romans used salts of this metal as dyeing mordants and as astringents to bind wounds, and alum is still used as a styptic. In 1761 Guyton de Morveau proposed calling the base alum alumine. In 1808, Humphry Davy identified the existence of a metal base of alum, which he named (see Spelling below for more information on the name). Friedrich Wohler is generally credited with isolating aluminium (Latin alumen, alum) in 1827. However, this metal was produced for the first time in impure form two years earlier by Danish physicist and chemist Hans Christian Orsted. Charles Martin Hall received the patent (400655) in 1886, on electrolytic process to extract aluminium. Henri Saint-Claire Deville (France) improved Wohler's method (1846) and presented these in a book in 1859 with two improvements to the process as to substitute potassium to sodium and double instead of simple chlorure. The invention of the Hall-Heroult process in 1886 made extracting aluminium from minerals inexpensive and is now in common use throughout the world. Aluminium is one of the few abundant elements that appears to have no beneficial function in living cells, but a few percent of people are allergic to it — they experience contact dermatitis from any form of it: an itchy rash from using styptic or antiperspirant products, digestive disorders and inability to absorb nutrients from eating food cooked in aluminium pans, and vomiting and other symptoms of poisoning from ingesting such products as Kaopectate® (anti-diarrhea product), Amphojel®, and Maalox® (antacids). In other persons, aluminium is not considered as toxic as heavy metals, but there is evidence of some toxicity if it is consumed in excessive amounts, although the use of aluminium cookware, popular because of its corrosion resistance and good heat conduction, has not been shown to lead to aluminium toxicity in general. Excessive consumption of antacids containing aluminium compounds and excessive use of aluminium-containing antiperspirants are more likely causes of toxicity. It has been suggested that aluminium may be linked to Alzheimer's disease, although that research has recently been refuted. Quick links
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