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Question
Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
Solution
Roasting involves the strong heating of an ore in the presence of an excess of air. On the other hand, calcination involves the strong heating of an ore in the absence of air.
Among these two, the process that is used for sulphide ores is roasting. This is because on roasting, metals sulphides get converted into metal oxides. This is done because the reduction of oxides is comparatively easier than the reduction of sulphid
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