When limestone is heated strongly, it gives off `CO_(2)`. In matallurgy this process is known as

Options

A. Calcination
B. Roasting
C. Smelting
D. Ore-dressing

Explanation

### Step-by-Step Solution:

1. **Understanding the Process**: When limestone (calcium carbonate, CaCO₃) is heated strongly, it decomposes to form calcium oxide (CaO) and carbon dioxide (CO₂). The reaction can be represented as:
\[ \text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g) \]

2. **Identifying the Metallurgical Process**: In metallurgy, the process of heating an ore to remove volatile impurities or to decompose the ore is known as calcination. This process typically occurs in the absence of air or in a limited supply of oxygen.

3. **Conclusion**: Therefore, the process described in the question, where limestone is heated to release CO₂, is known as **calcination**.

### Final Answer:
The process is known as **calcination**.

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