Why the Blast Furnace can be used to extract iron from Fe2O3 but not Aluminium from Al2O3.?

Iron is liberated from it's oxide in a blast furnace by carbon monoxide, the carbon monoxide simply removes oxygen from the iron oxide to become carbon dioxideleaving elemental iron. The same process will not work with aluminum oxide because aluminum has a much higher electropositive potential than iron. What this means in simple language is that aluminum gives up more energy than iron when it forms it's oxide and it takes more energy to remove oxygen from aluminum oxides than it does from iron oxides.