Why is chalcocite roasted and not calcined during extraction of copper ?

Explanation

### Step-by-Step Solution:

1. **Understanding the Terms:**
- **Calcination**: This process involves heating carbonate or hydroxide ores to convert them into oxides. It typically involves the removal of carbon dioxide (CO2) or water (H2O).
- **Roasting**: This process involves heating sulfide ores in the presence of oxygen to convert them into oxides, releasing sulfur dioxide (SO2) in the process.

2. **Identifying the Ore:**
- Chalcocite is a copper sulfide ore with the chemical formula Cu2S. Since it is a sulfide ore, it needs to undergo roasting rather than calcination.
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