Extraction of aluminium from aluminium oxide (Al₂O₃) is best done by

In the metallurgy of aluminum, purified Al₂O₃ is mixed with Na₃AlF₆
or CaF₂ which lowers the melting point of the mix and brings
conductivity. The fused matrix is electrolysed.This process of electrolysis is widely
known as Hall-Heroult process.

$$\begin{gathered} \mathrm{Cathode}: {\mathrm{Al}}^{3+}{ }_{\left(\mathrm{molten}\right)}+ 3{\mathrm{e}}^{-} \stackrel{ }{\to }{\mathrm{Al}}_{\left(\mathrm{l}\right)} \\ \mathrm{Anode}: {\mathrm{C}}_{\left(\mathrm{s}\right)}+ {\mathrm{O}}^{2-}\stackrel{ }{\to } {\mathrm{CO}}_{\left(\mathrm{g}\right)}+2{\mathrm{e}}^{–} \\ {\mathrm{C}}_{\left(\mathrm{s}\right)} + 2{\mathrm{O}}^{2-}\stackrel{ }{\to } {\mathrm{CO}}_2{ }_{\left(\mathrm{g}\right)}+4{\mathrm{e}}^{–} \end{gathered}$$