Roasting is used for sulphide ores, while calcination is used for carbonate ores. Why?

Question

Accepted Answer

: Roasting (heating in presence of air) helps convert sulphide ores into oxides by reacting the sulphide with oxygen. Calcination (heating in absence of air) is used for carbonate ores because heating alone, without needing oxygen, is enough to decompose a carbonate into its oxide and carbon dioxide.