Question

Answer the following questions with respect to the electrolytic process in the extraction of aluminum.

1. Identify the components of the electrolyte other than pure alumina and the role played by each.
2. Explain why powdered coke is sprinkled over the electrolytic mixture.

Answer 1

1: The components of the electrolyte other than pure alumina and the role played by each is as follows:

1. Alumina $\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)$: It is the main compound yielding aluminum.
2. Cryolite $\left({\mathrm{Na}}_3{\mathrm{AlF}}_6\right)$: It acts as a solvent and lowers the fusion temperature from $2050°\mathrm{C}\mathrm{to}950°\mathrm{C}$.
3. Fluorspar $\left({\mathrm{CaF}}_2\right)$: It acts as a solvent and increases the conductivity of the electrolytic mixture.

2: Powdered coke is sprinkled over the surface of the electrolytic mixture to prevent heat loss by radiation and prevents carbon anode from burning in the air.