Q. Extraction of Aluminium?
Aluminium cannot be extirpated economically from the silicate minerals. Therefore bauxite is the most important ore for the extraction of alumimum, but this has many problems. Al203 is a very stable compound. It is not reduced by heating in hydrogen. On strong heating with carbon, Al203, gives the carbide, AI4,C3,. As Al203 does not melt below 2300 K, it cannot be electrolysed conveniently. However, electrolysis of a solution of A120, in fused cryolite occurs at a much lower temperature of 1100-1300 K. Thus, aluminium is extracted by electrolysis of purified alumina in fused cryolite.