Describe electrolosis of aluminium oxide?

1) Aluminium is mixed with cryolite to reduce boiling point 2)At the cathode, Al3+ +3e- --> Al 3)At the anode, 2O2- --> O2 + 42e- ,the oxygen atoms pair up forming O2 so equation is doubled 4)The anode must be raplaced regularly as it reacts with oxygen forming CO2 5)Melting the compound requires energy, loads of energy is needed for electric curent