Define the term used in metallurgy.
Roasting

Explanation

**Step-by-Step Solution:**

1. **Definition of Roasting:**
Roasting is a metallurgical process used to extract metals from their sulphide ores.

2. **Process Description:**
- The process involves heating the metal sulphide ore above its melting point.
- This heating occurs in the presence of a sufficient supply of air (which contains oxygen).
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