Extracting aluminium
Aluminum ore- is called bauxite. The bauxite is purified to
yield a white powder aluminium oxide from which
aluminium can be extracted.
Aluminium is the most abundant metal on earth…, but it is
expensive, largely because of the amount of electricity use
in extraction process
Aluminium can’t be extracted by reduction of carbon as it
is highly reactive than carbon
Instead, it is dissolved in molten cryolite - an aluminium
compound with a lower melting point than aluminium
oxide. The use of molten cryolite as a solvent reduces some
of the energy costs involved in extracting aluminium
Aluminium ions receive electronsAl3+ + 3e- → Al
Oxide ions lose electrons at the positive electrodes and are
oxidised to oxygen gas:
2O2- → O2 + 4eHalf equations are
Al3+ + 3e- → Al
The anode is the aluminium
The reducing agent is aluminium of the aluminium oxide
2O2- → O2 + 4eThe cathode is oxygen
The oxidizing agent is the oxide of the aluminium oxide
This oxygen reacts with the carbon of the positive
electrodes, forming carbon dioxide, so they gradually burn
away. As a result, the positive electrodes have to be
replaced frequently. This adds to the cost of the process.