Zinc blende is ZnS. For the extraction of zinc from zinc blende, the ore is first concentrated by the method of froth floatation. The concentrated ore is then roasted by heating the ore in the presence of oxygen to give ZnO releasing SO2. The ZnS is further reduced using coke at temperature of 673 k giving zinc metal.
2ZnS + 3O2 → 2ZnO + 2SO2
ZnO + C → Zn + CO