What is meant by refining of metals? Name the most widely used method of refining impure metals produced by various reduction processes. Describe with the help of a labelled diagram how this method may be used for refining of copper.

Explanation

Process of obtaining pure metal from its impure form is called refining of metals. The most widely used method for refining impure metals is electrolytic refining. Electrolytic refining of copper: In electrolytic refining of copper, electrolyte is a solution of acidified copper sulphate. Anode is made up of impure copper. Cathode is made up of a strip of pure copper metal. On passing current through the electrolyte, pure copper metal from the anode dissolves into the electrolyte i.e., acidified copper sulphate. Cu (Impure copper) `® Cu^(2+) + 2e`
At cathode: An equivalent amount of pure metal from the electrolyte is deposited on the cathode.
(Pure copper) `Cu^(2+) + 2e^(-)a Cu`
The soluble impurities go into the solution, whereas, the insoluble impurities settle down at the bottom of the anode and are known as anode mud.