Extraction of AluminiumExtraction of Aluminium

Aluminium is extracted using electrolysis because it is too reactive

to be extracted using carbon.

Raw materialsRaw materials

Ore – bauxite – aluminium oxide

The ore is dissolved in cryolite to lower the melting point.

The electrolysis cellThe electrolysis cellCarbon anode

Moltenaluminium oxide

cathode Oxygen bubbles

Steel caseMolten aluminium

Temperature 900 C

Reactions in the cellReactions 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.

CostCost

Extracting aluminium is expensive because of the high cost of electricity. Extraction takes place where there is acheap source of electricity e.g. hydroelectric power