About Aluminum, Cans and Recycling
Aluminum metal is produced commercially by electrolysis of Aluminum Oxide using carbon electrodes.

2 Al2O3 -------> 4 Al + 3 O2 (electrolysis)

Reaction at the CATHODE Al+3 + 3 e- -------> Al

Reaction at the ANODE 2 O-2 -------> O2 + 4 e-

  • The reaction is carried out in the molten state at about 1000 șC.
  • Cryolite Na3AlF6 is added to lower the melting point of Aluminum Oxide.
  • The CATHODE (where Reduction takes place) and ANODE (where Oxidation takes place) are made of carbon (graphite)
  • Aluminum forms at the CATHODE. The molten metal sinks to the bottom of the cell.
  • Oxygen is produced at the Carbon ANODE. The carbon reacts further with the Oxygen to give Carbon Dioxide as well as Carbon Monoxide.

The Economics of Recycling

Preparation of Aluminum from its ore (Al2O3) is an energy intensive process.

To prepare one mole of Al requires........................................ 780 kj

To melt 1 mole of Al (m.p. 660șC) requires............................. 26 kj

1 mole of Aluminum contains.................................................. 26.98 g

© RWK 1997