Describe the role of the following in the process mentioned.
(i) Silica in the extraction of copper.
(ii) Cryolite in the extraction of aluminium.
(iii) Iodine in the refining of Zirconium.
(iv) Sodium cyanide in froth floatation.

Explain the principle of electrolytic refining with an example.

The selection of reducing agent depends on the thermodynamic factor: Explain with an example.

Give the limitations of Ellingham diagram.

Write a short note on electrochemical principles of metallurgy.