Why is Aluminium Oxide Dissolved in Molten Cryolite?

why is aluminium oxide dissolved in molten cryolite?

The main reason why aluminium oxide is dissolved in molten cryolite is that it has a lower melting point than pure aluminium oxide. This saves on energy costs in the production of aluminium and reduces the overall cost of the extraction process.

Electrolysis is a chemical reaction whereby ions from one electrode are passed through an electrolyte and reduced to a substance. Aluminium ions gain electrons from the cathode, and oxidation of oxygen ions takes place at the anode.

Aluminum is a metal that can be used for many purposes including: electrical components, wire guides, machinery seals and metering devices. It is also a very durable and strong material for use in industry.

In the early 1880s American chemist Charles Martin Hall invented a method of making aluminium by electrolysis that greatly reduced its price. He began by using a clay crucible to heat up a solution of molten cryolite (sodium aluminum fluoride) at 1000degC.

He mixed a small amount of bauxite with the cryolite to make a mixture that would melt at a temperature below the melting point of the two pure substances. When he ran the first electrolysis cell in February 1886 he discovered that the aluminium metal formed at the cathode and sank to the bottom of the tank where it was tapped off as the pure molten metal.

Hall was awarded the Perkin Medal in 1911 for his work, and the resulting aluminium metal is still very useful in the world today. It is also used to make alloys with other metals for more sophisticated applications, such as rubies and sapphires.