Extracting Metals by Electrolysis

Key Stage 3

Electrolysis is a way to extract metals from minerals when the metal is more reactive than Carbon.

Metals that are more reactive than Carbon cannot be displaced with Carbon so electrolysis is used to extract them.


Carbon electrodes are used to pass an Electrical Current through the molten mineral. The metal collects at the cathode which carries a negative charge and the pure metal is removed from the electrolysis cell.

Extraction of metals by electrolysis is a method of obtaining a metal from a mineral.

Electrolysis is usually used to extract metals when the metal is more reactive than Carbon or the mineral is soluble in water making it cheaper to extract by electrolysis than by smelting.

There are two possible methods used to extract metals by electrolysis:

Electrolysis of the Mineral in Solution - Used when the mineral is soluble in water and the metal does not react with water.
Electrolysis of the Molten Mineral - Used when the mineral is insoluble in water or the metal reacts strongly with water.

Aluminium is a special case in which the mineral is not dissolved in water but in a solvent called Cryolite at very high temperatures. This is done because the mineral melts at an even higher temperature than the cryolite so it is easier to dissolve it in the cryolite than to heat the mineral beyond its melting point.

Used when the mineral is insoluble in water or the metal reacts strongly with water.

Non-metal ionic elements or compounds will be collected at the anode where they lose their extra electrons.

Metal ions will be collected at the cathode where they gain electrons.

Used when the mineral is soluble in water and the metal does not react with water.

Non-metal ionic elements or compounds will be collected at the anode where they lose their extra electrons.

Metal ions less reactive than Hydrogen will be collected at the cathode where they gain electrons.