Write balanced equations for "the extraction of copper from pyrites by self-reduction".

Explanation

To write balanced equations for the extraction of copper from pyrites (CuFeS2) by self-reduction, we will follow the steps involved in the process.

### Step 1: Roasting of Copper Pyrite
The first step involves the roasting of copper pyrite (CuFeS2) in the presence of oxygen. This leads to the formation of copper(I) sulfide (Cu2S), iron(II) sulfide (FeS), and sulfur dioxide (SO2).

**Balanced Equation:**
\[ 2 \text{CuFeS}_2 + 5 \text{O}_2 \rightarrow 2 \text{Cu}_2\text{S} + 2 \text{FeS} + 4 \text{SO}_2 \]

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