State the role of silica in the metallurgy of copper.

Explanation

**Step-by-step text solution:**

1. **Introduction to Copper Extraction:**
The primary ore used for the extraction of copper is copper pyrite (CuFeS₂). The metallurgy of copper involves several processes, including roasting and smelting.

2. **Roasting Process:**
The first step in the extraction of copper is the roasting of copper pyrite. During roasting, the ore is heated in the presence of oxygen. This process removes impurities such as arsenic and antimony, which are converted into volatile oxides, and sulfur is oxidized to sulfur dioxide (SO₂).

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