What is the role of cryllite in the metallurgy of aluminimum?
Aluminium metal is obtained by the electrolytic reduction of alumina (Hall- Heroult process). The melting point of pure alumina is very high (2323K). Cryolite (Na3AIF6) and / or fluorspar (CaF2) is added to alumina because
(i) it lowers the melting point of the mixture (from 2323 K to 1140 K).
(ii) it also makes it a better conductor of electricity of Al2O3.