Metal Extraction by Electrolysis

Electrolysis is a method used for the extraction of metals from their ores which are typically displaced in the activity series, like aluminium and sodium.
In this process, electricity is used to instigate chemical changes that would be otherwise difficult or impossible to achieve.
The extraction of metal through this process involves the use of an electrolyte, an electric current, and two electrodes (an anode and a cathode).
The electrolyte is a substance that contains free ions and hence, can conduct electricity. This could be a molten ionic compound or a dissolved ionic compound.
For example, in the case of aluminium, the compound used is aluminium oxide which is dissolved in molten cryolite to reduce the melting point and to increase conductivity.
The electric current is passed through the electrolyte. The free ions in the electrolyte move towards the electrodes, where they either gain or lose electrons, undergoing reduction or oxidation.
Reduction occurs at the cathode (negative electrode) where ions gain electrons. Oxidation occurs at the anode (positive electrode) where ions lose electrons.
This process results in the pure metal being deposited at the cathode and the non-metal part of the compound being released at the anode.
For instance, in the extraction of aluminium, Al3+ ions (from the electrolyte) gain electrons at the cathode and is reduced to aluminium atoms. Meanwhile, oxygen (from the Al2O3 mixing with carbon electrodes) is oxidised at the anode, forming carbon dioxide.
This method is energy-intensive and contributes to CO2 emissions, posing environmental challenges. Thus, the sustainable use of this method requires solutions for energy efficiency and CO2 capture or neutralisation.
Recycling of metals is highly encouraged as it uses significantly less energy than electrolysis and helps in conservation of natural resources.