Extraction of Zinc

Extraction of Zinc

 

Ores:	Zinc Blende, ZnS
	Calamine, ZnCO3
	Zincite, ZnO

1. Concentration:
   Powdered Zinc Blende is concentrated by froth floatation process.
    
2. Roasting:
   
   2ZnS + 3O₂      2ZnO + 2SO₂
    
3. Reduction:
   
   ZnO + C  Zn + CO
    
4. Purification:
   Impure Zinc obtained above contain impurities of Pb, Fe, Cd, As etc. This impure Zinc is known as spelter. Firstly, Cd is distilled off at 800C and then electrolytic purification is done using impure Zn as anode and cathode consists of sheets of pure Al. Pure Zn is scrapped off from Al-sheets.