Question

The following questions are relevant to the extraction of aluminum.

Along with cryolite and alumina, another substance is added to the electrolyte mixture.

Answer 1

1. During the extraction of Aluminum Cryolite is added for reducing the melting point of Alumina.
2. In addition to this Fluorspar($\mathit{C}\mathit{a}{\mathit{F}}_{\mathbf{2}}$) or Calcium fluoride is also added.
3. Fluorspar will increase the conductivity of the electrolyte.
4. Fluorspar is the substance act as a solvent and it increases conductivity. (Pure alumina melts at about 2000^oC and is a bad conductor of electricity.
5. If fused cryolite and fluorspar is added, the mixture melts at 900^oC and Al₂​O3​ becomes a good conductor of electricity.)