. Describe the underlying principle of each of the following metal refining methods

Best Answer

(i) Electrolytic refining: In this method, the impure metal is made to act as anode. A strip of same metal in pure form is used as cathode. They are put in a suitable electrolytic bath containing soluble salt of same metal. When electric current is passed, the metal from the anode goes into solution as ions due to oxidation while pure metal gets deposited at the cathode due to reduction of metal ions. The less electropositive impurities settle down below the anode as anode mud

(ii) Vapour phase refining of metals: In this method, crude metal is freed from impurities by first converting it into volatile compound and collected elsewhere. It is then decomposed to give pure metal. For example refining of nickel by Mond process