Question

can displacment reaction can use to separate aluminium from aluminiumoxide

Answer 1

Yes it is used by carbon displacement
Al2O3+C =Al+CO

Answer by cp

Answer 2

Reactive metals such as aluminium are extracted by electrolysis, while a less-reactive metal such as iron may be extracted by reduction with carbon. Gold, because it is so unreactive, is found as the native metal and not as a compound, so it does not need to be chemically separated.