Which method is used to obtain ultra-pure copper?

The zone refining method is based on which principle?

Refining of silver is done by :

Which metal is purified using the Mond process?

The method used for obtaining highly pure silicon,which is used as a semiconductor material,is:

In the electrolytic refining of metals,the electrolysis of an aqueous solution of its complex salt is performed using an impure metal as the anode and a strip of pure metal as the cathode. This method cannot be used for the refining of which of the following metals?