The process used for the extraction of aluminium is called ____________?

The industrial extraction of aluminium is carried out by the Hall-Héroult process, named after Charles Martin Hall and Paul Héroult, who independently developed the method in 1886. Aluminium is extracted from bauxite ore (Al₂O₃·2H₂O), which is first purified to produce pure alumina (Al₂O₃) through the Bayer process. Once purified, the alumina is converted into metallic aluminium by electrolysis.

In the Hall-Héroult process, alumina is dissolved in molten cryolite (Na₃AlF₆) to lower its melting point and improve electrical conductivity. The electrolytic cell used for this process consists of a carbon-lined steel container acting as the cathode, while graphite rods serve as anodes. When electric current passes through the molten mixture, aluminium ions are reduced at the cathode to form molten aluminium, and oxygen ions are oxidized at the anode to produce carbon dioxide.

The main reaction at the cathode is:
Al3++3e−→Al(l)Al^{3+} + 3e^- → Al(l)Al3++3e−→Al(l)
At the anode:
2O2−+C→CO2+4e−2O^{2-} + C → CO₂ + 4e^-2O2−+C→CO2+4e−

The molten aluminium collects at the bottom of the cell and is periodically tapped off. This process is highly energy-intensive but remains the most economical and efficient method for large-scale aluminium production.

The Hall-Héroult process is distinct from other named processes like the Thermite process (used for metal reduction using aluminium powder), the Haber process (for ammonia synthesis), and the Contact process (for sulfuric acid manufacture).

Thus, the extraction of aluminium from alumina through electrolysis in molten cryolite is called the Hall process, a cornerstone of industrial inorganic chemistry.