See explanation below.
Work Step by Step
The extraction is done by electrolysis. But first the aluminium oxide must be made molten so that electricity can pass through it. Aluminium oxide has a very high melting point (over 2,000°C), so it would be expensive to melt it. Instead, it is dissolved in molten cryolite, an aluminium compound with a lower melting point than aluminium oxide. The use of cryolite reduces some of the energy costs involved in extracting aluminium.