Discovery Information
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Who: Hans Christian Oersted |
When: 1825 |
Where: Denmark |
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Name Origin
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Latin: alumen (alun). |
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Sources
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Most plentiful metal in earth's crust (7.5% - 8.1%), but virtually never occurs in free form, so rare that it was once considered
a precious metal more valuable than gold! Obtained by electrolysis from bauxite (Al2O2).
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Uses
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Kitchen utensils, building decorations, electrical transmission (not nearly as conductive as copper, but cheaper) as well as packaging (can, foil etc.). Aluminium alloys form vital components of aircraft and rockets as a
result of their high strength to weight ratio. Alloys containing copper, magnesium, silicon, manganese and other metals are much stronger and more durable than aluminium, making aluminium useful in the manufacture of aircraft
and rockets.
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Most electronic appliances that require cooling of their internal devices (like transistors, CPUs - semiconductors in general)
have heat sinks that are made of aluminium due to its ease of manufacture and good heat conductivity. Copper heat sinks are smaller although more expensive and harder to manufacture.
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Aluminium oxide (Al2O3), alumina, is found naturally as corundum (rubies and sapphires), emery, and is used in glass making. Synthetic ruby and
sapphire are used in lasers.
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Powdered aluminium, a commonly used silvering agent in paint. Aluminium flakes may also be included in undercoat paints, particularly
wood primer - on drying, the flakes overlap to produce a water resistant barrier.
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Notes
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While aluminium was discovered by Hans Christian Oersted, Denmark, 1825 (impure form); most credit Wohler with isolating it in1827. Actually the ancient Greeks and Romans used alum (aluminium sulfate with potassium) in medicine and in dying. de Morveau recognized the base in alum in 1761 and proposed it be called alumine. Lavoisier thought
that alum was an oxide of this undiscovered metal. In 1807 Davy proposed the name alumium for this undiscovered metal, but it wasn't until 1827 that Wohler actually isolated aluminium, though an impure form was isolated by Oersted two years earlier. The new metal was called aluminum. Two years later it was changed to aluminium to conform with the "ium"
in most other elements. American Chemical Society changed the spelling back to aluminum in 1925, which we American's still
use. In England and elsewhere in the world they still spell it aluminium. So if you hear someone say "al-u-min'-i-um foil"
instead of aluminum foil, you'll know where it came from.
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It is the second most malleable metal (gold being first) and the sixth most ductile.
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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 antiperspirant
products, digestive disorders and inability to absorb nutrients from eating food cooked in aluminium pans.
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