Electrolytic Refining of Metals |  

Our topic for today is Electrolytic Refining of Metals.
Electrolytic refining is the process of obtaining pure metals like gold, silver, copper etc. by the process of electrolysis.
Let us learn how copper is refined electrolytically.
Take acidified copper sulphate solution as the electrolyte.
Take a thick rod of impure copper and a thin rod of pure copper.
Make impure copper as the anode and pure copper as the cathode.
When current is passed through the solution, the CuSO4 electrolyte splits into copper ions and sulphate ions.
The copper ions from the electrolyte get attracted towards the cathode.
The copper ions gain 2 electrons from the cathode and deposit as pure copper atoms on the thin copper rod.
At the same time, the copper atoms from the anode lose 2 electrons, convert into copper ions and dissolve in the electrolytic solution.
In this way, indirectly, copper atoms from the anode deposit on the cathode.
Hence, size of anode decreases and size of cathode increases.
In this way, all the pure copper from the anode deposits on the cathode.
The impurities in the impure copper rod settle down as anode mud at the bottom of the container.