Aluminium Extraction and Uses

Aluminium Mining Aluminium Ore is called Bauxite. Bauxite is a red mineral made of aluminium oxide and iron oxides. Bauxite is mined in various places, e.g. Russia, Jamaica

Bauxite Purification Bauxite is heated with sodium hydroxide. This dissolves the alumina but not the other minerals. The residue is filtered off and disposed of. The filtrate is acidified and heated to produce pure alumina, aluminium oxide powder.

Extracting aluminium Aluminium is more reactive than carbon. So carbon will not reduce aluminium oxide. Aluminium cannot be extracted in a blast furnace. Aluminium is extracted using electricity in a process called electrolysis.

The electrolysis cell

How it works + Direct Current Al2O3 2Al3+ + 3O2- Anode Al3+ O2- O2- Cathode -

At the anode 2O2-  O2 + 4e- O2 + C  CO2 + anode e- e- O2- O2 O2- CO2 positive O2 + C  CO2

At the cathode Al3+ + 3e-  Al - al l i q u i d Cathode e- e- e- Al3+ negative

Quick Review + + Direct Current Anode Anode CO2 CO2 O2 Al3+ O2- O2- Cathode -

At the electrodes. At the negative cathode Positive Aluminium ions drift to the cathode. They gain electrons and become aluminium atoms Al3+ + 3e-  Al At the positive anode Negative oxide ions drift to the positive anode. They lose electrons and become oxygen gas molecules. 2O2-  O2 + 4e-

Making stuff

Uses of aluminium Power cables Saucepans Aeroplanes Bicycles Cars Battleships Cooking foil Cans Space blankets Statues Window frames Light Light, unreactive Light, doesn’t rust Light, radar quiet Reflective, unreactive Unreactive Reflective