The main function of roasting is 
(A)  To remove the volatile impurities
 (B)  Oxidation
(C)  Reduction    
(D)  To make slag
 

Roasting : It is the process of converting an ores to oxide by strongly heating it in the presence of excess of air . For example sulphide ores are converted into their respective oxide by heating in the presence of air.

eg : 2 ZnS +3O₂ --------> 2 ZnO + 2SO₂ .

Option B is correct.As oxidation of the metal  ores takes place.


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