Write the chemical equations involved in the preparation of elemental boron from mineral colemanite.

Explanation

To prepare elemental boron from the mineral colemanite (Ca2B6O11·5H2O), we can follow a series of chemical reactions. Here are the steps involved along with the balanced chemical equations:

### Step 1: Reaction of Colemanite with Sulfur Dioxide and Water
The first step involves the reaction of colemanite with sulfur dioxide (SO2) in the presence of water (H2O). This reaction produces calcium bisulfite (Ca(HSO3)2) and boric acid (H3BO3).

**Chemical Equation:**
\[ \text{Ca}_2\text{B}_6\text{O}_{11} \cdot 5\text{H}_2\text{O} + 4\text{SO}_2 + 11\text{H}_2\text{O} \rightarrow 2\text{Ca(HSO}_3\text{)}_2 + 6\text{H}_3\text{BO}_3 \]

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