The chief ore of Zn is the sulphide, ZnS. The ore is concentrated by froth floatation process and then heated in air to convert ZnS to ZnO . ( Zn = 65.4 ) 2 Z n S + 3 O 2 75% 2 Z n O + 2 S O 2 Z

Question

The chief ore of Zn is the sulphide, ZnS. The ore is concentrated by froth floatation process and then heated in air to convert ZnS to $ZnO . (Zn = 65.4)$

$2 Z n S + 3 O_{2} 75% 2 Z n O + 2 S O_{2}$

$Z n O + H_{2} S O_{4} 100% Z n S O_{4} + H_{2} O$

$2 Z n S O_{4} + 2 H_{2} O 80% 2 Z n + 2 H_{2} S O_{4} + O_{2}$

What mass (in kg) of Zn will be obtained from a sample of ore containing 487 kg of ZnS?

TestHub · Accepted Answer

Molar mass of ZnS = 65.4 + 32 = 97.4 g m o l − 1 487 k g Z n S = 97.4 487 ​ = 5 km o l . Overall yield = 75% × 100% × 80% = 60% . From stoichiometry, 1 m o lZ n S g i v es 1 m o lZ n , so actual Zn obtained: 5 × 0.60 = 3 km o l M a sso f Z n = 3 × 65.4 = 196.2 k g

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