ABSTRACT
Aluminum is one of the most abundant elements in the earth’s crust and is a resource that will be virtually impossible to exhaust (Altenpohl, 1998). However, aluminum forms exceedingly strong bonds to oxygen and the lattice energy of Al2O3 is ~15,000 kJ/mol, one of the highest known. By comparison, the lattice energy of MgO is ~3800 kJ/mol. Thus, the primary consideration in the manufacture and recycling of aluminum is the energy required to reduce the element and free it from such a stablebonding environment. This requires approximately 13 kWh/kg in the primary re™ning (Altenpohl, 1998). It is ideal, then, to recycle aluminum products to take advantage of the energy that has already been expended in obtaining the element. For example, primary aluminum smelting requires ~118,000 MJ of energy while recycling requires only ~7000 MJ. Recyclingused aluminum requires only about 5% of the energy required to make fresh aluminum from bauxite ore.
