How is aluminium extracted from its ore?
The extraction of aluminium from bauxite ore is achieved through the Bayer process. This process was developed in 1887 by Karl Bayer, and is still used today in largely unchanged form.Sodium Hydroxide BathThe most common aluminium ore, bauxite, is crushed and placed in a hot solution of sodium hydroxide. The aluminium oxide present in the bauxite reacts with and dissolves into the liquid sodium hydroxide, forming sodium tetrahydroxoaluminate.Bauxite ImpuritiesOther metal oxides present in bauxite, such as iron and titanium, do not react with sodium hydroxide and remain in solid form. Any silicon dioxide that dissolves is separated through the process of precipitation in the next step.FiltrationAll bauxite impurities remaining in the sodium hydroxide solution are filtered out. The filtered material is known as “red mud,” a waste product.PrecipitationAluminium hydroxide is added to the remaining solution of sodium tetrahydroxoaluminate to “seed” the solution.
Aluminium Ore is called bauxite. The Bayer process is the principal industrial means of refining bauxite to produce alumina. The Hall-Héroult process is the major industrial process for the production of aluminium from alumina. Both Bayer process and Hall-heroult process are available on wiki. Both remain quite unchanged since their invention – at least the theory behind them. ENgineering and technology have allowed them to be very highly fine tuned though.
