Describe the roles of the following:

1. NaCN in the extraction of silver from a silver ore.

2. Iodine in the refining of titanium.

3. Cryolite in the metallurgy of aluminium.

Extraction of Silver

  • In the extraction of gold and silver, the metal is leached with NaCN or KCN, which is an oxidation reaction.

  • During the process, Ag is oxidised to Ag+ 

Here M =Ag or Au.


van Arkel Method for refining zirconium or titanium

  • All the oxygen and nitrogen present as impurity are removed.

  • Crude metal is heated with iodine in an evacuated vessel.



  • Metal iodide is decomposed on a tungsten filament, electrically heated to about 1800 K to give the pure metal.





Crayolite (Na3AlF6 or CaF2) is added to alumina to lower the melting point, and to increase the conductivity of the electrolyte.

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