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Question
Answer the following question :
What is the difference between calcination and roasting.
Solution
| Calcination | Roasting |
| 1. The ore is heated in the absence of air | 1. The ore is heated in excess of air. |
| 2. Moisture and organic impurities are removed, and the ore becomes porous and more reactive. |
2. Volatile impurities are |
| 3. Carbonate and hydrated ores are calcined, and CO2 or water vapour is given off. ZnCO3 → ZnO + CO2 |
3. Sulphide ores are roasted, so SO2 is given off. \[\ce{2ZnS + 3O2 ->[80°-90°] 2ZnO + 2S}\] |
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