Aluminium oxide may be electrolysed at $1000^{\circ} C$ to furnish aluminium metal (Atomic mass =27 amu; 1 faraday= 96,500 Coulombs). The cathode reaction is <br> $Al^{3+} + 3e^- \to Al^0$ <br> To prepare 5.12 Kg of aluminium metal by this method would require :