Question

Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?
(a) CO₂ is more volatile than CS₂
(b) Metal sulphides are thermodynamically more stable than CS₂
(c) CO₂ is thermodynamically more stable than CS₂
(d) Metal sulphides are less stable than the corresponding oxides

Answer 1

(a) : Oxidising roasting is a very common type of roasting in metallurgy and is carried out to remove sulphur and arsenic in the form of their volatile oxides.CS₂ is more volatile than CO₂. So option (a) is of no significance for roasting sulphide ores to their oxides. The reduction process is on the thermodynamic stability of the products and not on their volatility.