How can you separate alumina from silica in a bauxite ore associated with silica? Give equations, if any.

Explanation

To separate alumina (Al₂O₃) from silica (SiO₂) in bauxite ore, we can follow these steps:

### Step 1: Digestion of Bauxite Ore
- **Process**: The bauxite ore is treated with concentrated sodium hydroxide (NaOH) solution.
- **Conditions**: The reaction is carried out at a temperature of 473 to 523 K and a pressure of 35 to 36 bar.
- **Equation**:
\[
\text{Al}_2\text{O}_3 + 2 \text{NaOH} + 3 \text{H}_2\text{O} \rightarrow 2 \text{NaAl(OH)}_4
...