Question

For the extraction of aluminium answer the following

Why is cryolite mixed with the ore?

Answer 1

1. The chief ore of aluminium is bauxite$\mathbf{(}\mathit{A}{\mathit{l}}_{\mathbf{2}}{\mathit{O}}_{\mathbf{3}}\mathbf{.}\mathbf{2}{\mathit{H}}_{\mathbf{2}}\mathit{O}\mathbf{)}$ or alumina.
2. Aluminium is extracted mainly by the process of electrolytic reduction technique.
3. In the first step, bauxite is purified and then the purified alumina is mixed or dissolved with cryolite$\mathbf{\left(}\mathit{N}{\mathit{a}}_{\mathbf{3}}\mathit{A}\mathit{l}{\mathit{F}}_{\mathbf{6}}\mathbf{\right)}$ and a little fluorspar($\mathit{C}\mathit{a}{\mathit{F}}_{\mathbf{2}}$).
4. This is because of the high melting point of alumina.
5. By mixing it with cryolite the melting point is reduced and more energy can be saved.

For reducing the melting point the ore of aluminium ($\mathit{A}\mathit{l}$) is mixed with cryolite.