1. Extraction of Aluminium I know how aluminium is extracted from its ore. L.O.

2. Aluminium: properties Aluminium is a reactive metal. We might expect it to corrode easily but a strong coating of oxide on it’s surface prevents this in most everyday situations. It has a low density which leads to its extensive use in the aerospace industry. Al O OO O O O O O O Coating of oxygen atoms prevents further attack

3. Aluminium: ores It occurs as bauxite ore which is a form of aluminium oxide. Because aluminium is so reactive carbon is unable to pull away the oxygen from it. moltenIt is extracted by electrolysis of molten bauxite. Early attempts at this failed because bauxite is so hard to melt. If cryolite is added, the bauxite melts more easily. This is an essential step in the extraction process.

4. A bauxite / cryolite mixture is melted in a steel container containing a carbon lining. Graphite (carbon) anodes Tank lined with carbon cathode Molten electrolyte bauxite + cryolite Steel case Graphite anodes are inserted into the molten electrolyte ready for electrolysis. Electrolytic extraction

5. Aluminium formation Opposite charges attract. And so positive aluminium ions move towards the negative cathode. At the cathode these ions gain electrons and turn into aluminium atoms.

6. Oxygen formation Negatively charged oxide ions move to the anode. Here they lose 2 electrons and so turn into neutral oxygen atoms. These atoms rapidly join into pairs to form normal oxygen gas.

7. Carbon dioxide formation Remember the electrolysis is carried out at high temperature. Under these conditions quite a lot of the oxygen reacts with the carbon anode. Carbon dioxide is formed and the anode is rapidly eaten away and frequently has to be replaced.

8. Extraction of aluminium: overall siphon Graphite / carbon anodes Molten aluminium Molten electrolyte bauxite + cryolite Tank lined with carbon cathode Molten aluminium out Steel case Vented cover

9. Compounds can be split up into the elements which make them using electricity. This is called electrolysis. The aluminium ore is aluminium oxide.

10. Common aluminium ore I axe tub Added to reduce melting point City role The electrodes are made out of Right ape Extracting aluminium is a Cretin duo bauxite cryolite graphite reduction Unscramble the words to end the sentences.

11. Aluminium – the overall process

12. 1.What do we call the substance added to the aluminium ore prior to electrolysis? Bauxite Electrolyte Cryolite

13. 2.What substance are the cathodes made from? Carbon Iron Aluminium

14. 3. What happens to the oxygen given off during electrolysis? It is given off as waste gases It reacts with the carbon electrodes to form carbon dioxide. It is collected at the bottom of the chamber.