In the Hall-Heroult process for the electrometallurgy of Aluminium, fluorspar () and cryolite () are — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

Purified alumina ($Al_2O_3$) has a very high melting point ($~2050^\circ C$) and is a poor electrical conductor. Cryolite and fluorspar are added to lower the melting point of the mixture to about $900^\circ C$ and to increase its electrical conductivity, allowing feasible electrolysis.