The operation of converting lime stone into quick lime by heating it to temperatures upto 900°C and releasing carbon dioxide is known as:
🔥 Understanding Lime Production Terminology
The production of lime from limestone is a multi-step process that happens in a kiln. Each step has a specific technical name. This question focuses on the central chemical reaction where the raw material is transformed into the final product.
🔬 Detailed Analysis of the Options
B. Calcining
This is the correct answer. Calcination is the specific term for the process of thermally decomposing a material by heating it to a high temperature. In this case, limestone (CaCO₃) is heated to around 900°C, which drives off carbon dioxide (CO₂) and leaves behind quicklime (CaO). This is the core chemical transformation in lime production.
A. Charging
This is incorrect. Charging refers to the physical operation of loading the raw materials (limestone and fuel) into the kiln. It is the first step, before heating begins.
C. Drawing
This is incorrect. Drawing refers to the physical operation of removing the final product (quicklime) from the kiln after the calcination is complete.
D. Hydrating
This is incorrect. Hydrating (or slaking) is the process of adding water to quicklime *after* it has been produced. This is a separate step that converts quicklime (CaO) into hydrated lime (Ca(OH)₂).
📊 Summary: Stages of Lime Production
| Term | Description | Stage in Process |
|---|---|---|
| Charging | Loading raw material into the kiln. | Beginning |
| Calcining | Heating to decompose limestone into quicklime. | Middle (The Reaction) |
| Drawing | Removing the finished quicklime from the kiln. | End |
| Hydrating | Adding water to quicklime after production. | Post-Production |
💡 Study Tips
- Calcination = Chemical Change: Remember that calcination is the chemical reaction part of the process.
- Charging/Drawing = Physical Actions: Charging is putting in, Drawing is taking out. These are physical operations, not chemical reactions.
- Hydrating = Adding Water: This is a separate, later step. Don't confuse it with the initial heating process.