Energy use in metal production

Energy is consumed at all stages in the production of primary metals - mining, beneficiation and chemical extraction - directly in the processes and indirectly through the production of inputs (such as electricity and reagents) used in the processes. The sum of the direct and indirect energies of the individual stages along the value-adding chain is the embodied energy of the metal. The embodied energy of the common metals varies widely, from typically around 20 MJ per kilogram for lead and steel to over 200 MJ per kilogram for aluminium. The chemical transformation stages (leaching, smelting, electrowinning, etc) contribute the largest component and mining the least