GATE 2024 MT – Question 60
A 1000 kg sphalerite concentrate containing 60% ZnS is completely roasted with stoichiometric pure oxygen. The oxygen required is ______ kg (one decimal place). Other components are inert. Atomic weights: Zn 65, S 32, O 16 g mol$^{-1}$.
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Correct answer: 295.0 to 300.0
Explanation
The roasting reaction is $\mathrm{ZnS}+\tfrac32\mathrm O_2\to\mathrm{ZnO}+\mathrm{SO}_2$.
The concentrate contains $0.60(1000)=600$ kg ZnS, or $600/97$ kmol.
Oxygen requirement is $(600/97)(1.5)(32)=296.907\ldots$ kg.
The answer is **296.9 kg**.