The extraction of Zinc from Zinc blende involves the following steps.
Concentration
The ore is crushed and then concentrated by froth-floatation process.
Roasting
The concentrated ore is then roasted in the presence of excess of air at about 1200 K.
2 ZnS + 3O2 → 2ZnO + 2SO2
Reduction
Zinc oxide is mixed with powdered coke and heated to 1673 K in a fire clay retort, in which ZnO is reduced to zinc metal.
ZnO + C ⎯1673 K→ Zn + CO
