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Extraction of Aluminum
Process: Electrolysis of aluminum oxide (bauxite) dissolved in molten cryolite.
Aluminium Oxide has a high melting point so requires more heat; cryolite reduces this,
making electrolysis feasible.
Another use of Cryolite is that it acts as a solvent for Aluminium
Electrolytic Cell Design:
Cathode (Reduction): Aluminum ions are reduced to molten aluminum.
Reaction: Al + 3e → Al
Anode (Oxidation): Oxide ions are oxidized to oxygen gas, which then reacts with carbon
anodes, producing CO2.
Reaction: 4Al ³⁺ + 12e ⁻ → 4Al
Anode Consumption: Anodes made of graphite must be replaced periodically due to
oxidation.
Energy and Cost Considerations:
The process is energy-intensive and costly, making aluminum relatively expensive.