14. Extraction of aluminium

What is placed where?

Molten aluminium oxide (bauxite) put in electrolysis bath

What does the electricity do to the aluminium?

It passes through and split it into aluminium and oxide ions

What happen to aluminium ions?

Positive -> attracted to cathode -> gain electrons (reduced) -> form aluminium metal

What happens to oxide ions?

Negative -> Attracted to anode -> lose electrons (oxidised) -> Forms oxygen gas

What happens to the oxygen gas?

Reacts with carbon in electrode which forms carbon dioxide and burns electrode away

What reduces costs?

Adding cryolite to aluminium oxide to lower melting temperature