ALUMINUM (AL)

last update 01 oct 08

* Aluminum is a member of the main group metals family:

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   ALUMINUM / Al / 13

   A soft, malleable, silvery, fairly reactive metal.  One isotope
   occurs in nature, Al<17/13>; it is stable.

     atomic weight:       26.981538
     abundance:           3rd
     density:             2.6989 g/cc
     melting point:       660 C      
     boiling point:       2,467 C
     valence:             3
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Aluminum is arguably the second most industrially important metal, after iron. It is found mostly in the form of bauxite ore, AlO(OH), and is refined by an energy-intensive electrolytic process. Tens of millions of tonnes are produced each year, with about the same amount recycled. With rising energy costs, aluminum recycling is becoming more important.

Of course, aluminum is of major importance as a structural material, particularly for aircraft where its high strength-to-weight ratio comes in handy, and is also used for electrical wiring; copper has better conductivity, but it is more expensive. Aluminum sulfate -- Al2(SO4)3+16H2O -- is used on a wide scale for paper treatment and water purification. When small amounts of lime (CaOH) and aluminum sulfate are introduced into cloudy water, they react to form aluminum hydroxide, which precipitates down to the bottom, carrying the impurities along with it.