Roasting is carried out to This question has multiple correct options

Roasting is a metallurgical process involving heating the ore in air. Its primary purpose is to convert sulphide ores to oxides (e.g., 2ZnS + 3O2 → 2ZnO + 2SO2), which are easier to reduce. While roasting also removes volatile impurities like sulphur, the main objective is oxidation. Option B (remove water of hydration) refers to calcination, option C (melt the ore) refers to smelting, and option D (remove carbon and sulphur impurities) is a secondary effect, not the primary purpose.