Extraction of Aluminium Aluminium is extracted using electrolysis because it is too reactive to be extracted using carbon.
Raw materials Ore – bauxite – aluminium oxide The ore is dissolved in cryolite to lower the melting point.
The electrolysis cell Carbon anode Molten aluminium oxide Oxygen bubbles cathode Molten aluminium Steel case Temperature 900 C
Reactions in the cell • At the cathode Al3+ + 3e- Al • At the anode 2O2- O2 + 4e- • The oxygen formed reacts with the carbon anodes to form carbon dioxide. • They have to be replaced periodically.
Cost Extracting aluminium is expensive because of the high cost of electricity. Extraction takes place where there is a cheap source of electricity e.g. hydroelectric power