Roasting: Roasting is a metallurgical process in which a sulfide ore is heated in the presence of excess oxygen (air) to convert it into an oxide. This process often releases sulfur dioxide (SO₂) gas as a byproduct.
Calcination: Calcination is a thermal treatment process in which an ore or other solid material is heated in the absence or limited supply of oxygen (air) to remove volatile impurities, such as moisture or carbon dioxide (CO₂), and to bring about thermal decomposition.
Roasting 🆚 Calcination
| Feature | Roasting | Calcination |
| Process | Heating of a sulfide ore in the presence of oxygen (air) | Heating of an ore in the absence or limited supply of air (oxygen) |
| Purpose | Converts sulfide ores into oxides and releases sulfur dioxide (SO₂) | Removes volatile impurities like moisture and carbon dioxide (CO₂) |
| Temperature | Typically carried out at a high temperature | Also involves high temperature but generally lower than roasting |
| Byproducts | Produces sulfur dioxide (SO₂) gas | Usually produces carbon dioxide (CO₂) or water vapor |
| Example | 2ZnS + 3O₂ → 2ZnO + 2SO₂ (zinc sulfide to zinc oxide) | CaCO₃ → CaO + CO₂ (calcium carbonate to calcium oxide) |
Industries Relying on Roasting and Calcination:
- Metallurgy: Extraction of metals from their ores. 1. Extraction of Metals from Ores – Different Processes Involved – Vedantu www.vedantu.com
- Cement production: Producing clinker, a key component of cement.
- Chemical industry: Production of various chemicals and compounds. 1. Calcination and Roasting- Definition, Differences and FAQs – Infinity Learn by Sri Chaitanya infinitylearn.com
- Environmental remediation: Treating contaminated materials.