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CH1012
ALUMINIUM
1. Aluminium                       electrometallurgy
• Most abundant metal by mass in the crust.
• the most common ore is bauxite (mostly Al2O3.nH2O - alumina, + SiO2, Fe2O3, TiO2)
   eg. Weipa COMALCO mine
• Step 1: bauxite is purified to obtain pure alumina Al2O3(s). The hydrometallurgical Bayer process uses NaOH (dissolves amph.  alumina & leaves Fe2O3 behind) then add H+.
 Al2O3(s) + 3H2O + 2OH-(aq) D 2Al(OH)4-(aq)
   eg. Gladstone QAL refinery
• Step 2: the Hall-Heroult process
is used to produce aluminum metal from alumina using electrolysis.
   eg. Gladstone COMALCO Boyne smelter
QAL 3.8million tons/year worlds largest produces 7% of the worlds alumina