Final answer:
Aluminum is extracted from bauxite ore by converting it to aluminum oxide with the Bayer Process and then electrolyzing this oxide. The key reaction at the cathode during electrolysis is Al³⁺ + 3e⁻ → Al(s), where aluminum ions are reduced to pure aluminum metal.
Step-by-step explanation:
Extraction of Aluminum from Bauxite
Aluminum extraction from its ore, bauxite, involves several steps.
The process begins with the conversion of bauxite into pure aluminum oxide via the Bayer Process.
Bauxite, consisting mainly of AlO(OH), is reacted with hot sodium hydroxide forming soluble sodium aluminate, with the reaction: AlO(OH)(s) + NaOH(aq) + H₂O(l) → Na[Al(OH)₄](aq).
Once the aluminum oxide is purified, it undergoes electrolysis in molten cryolite.
The ionic equation for the reduction at the cathode during electrolysis is: Al³⁺ + 3e⁻ → Al(s).
The extraction process involves heating the precipitated aluminum hydroxide to produce aluminum oxide, which is then dissolved in a molten mixture of cryolite (Na₃AlF₆) and calcium fluoride (CaF₂) for the electrolysis.
At the cathode, aluminum ions are reduced to metallic aluminum, while oxygen and other gases are produced at the anode.