Cryolite plays a crucial role in the aluminium extraction process by lowering the melting point of the mixture and enhancing its conductivity.

Chemically known as sodium aluminium fluoride, or $Na_3AlF_6$, cryolite is essential for extracting aluminium from its ore, bauxite. This extraction process, referred to as the Hall-Heroult process, involves the electrolysis of alumina, which is aluminium oxide. However, alumina has a high melting point exceeding $2000$ degrees Celsius, making the extraction process both energy-intensive and costly.

Cryolite addresses this challenge effectively. When incorporated into the mixture, cryolite reduces the melting point of alumina to approximately $1000$ degrees Celsius. This significant reduction in melting point decreases the energy required to keep the mixture in a molten state, thereby enhancing the overall efficiency and cost-effectiveness of the extraction process.

Moreover, cryolite also improves the conductivity of the mixture. This enhancement is critical, as the electrolysis process depends on the smooth flow of electric current through the mixture. By increasing conductivity, cryolite facilitates easier current flow, further optimizing the efficiency of the extraction process.

In summary, cryolite is an indispensable component in aluminium extraction. It lowers the melting point of alumina, reducing energy consumption, and improves the mixture’s conductivity, ensuring a more efficient flow of electric current during electrolysis. Without cryolite, the extraction of aluminium would be considerably more challenging and expensive.