Material & energy requirements Technical University of Crete Mining Department of Mineral Resources Engineering Metalurgical Processes – Prof. Komnitsas Athanasios Paraschos

 Aluminum is a light metal with density of 2.7g/cm 3 (three times less than of steel).  It is one of those elements which are excessive on earth. It is an excellent heat and electrical conductor with very good reflectivity, resistance to corrosion and ductility.  Aluminum is used extensively in electronics infrastructure, packaging and transportation

Source Worldwide Aluminum production in 2010

 In 2010, global Al production is 41,4million tons  Global average energy consumption is 15kWh/kg Aluminum  Thus,  Electricity consumption is 621 billion kilowatt hours of electricity  Global electricity production is billion kilowatt hours  Therefore,  Three percent of the total electrical supply goes to aluminum extraction

 Mostly aluminium is produced in two ways;  Primarily Production Process  Bayer process: Bauxite refining  Hall-Héroult process : Reduction of Alumina to Aluminum  Secondary Production Process  Recycling of scraps containing Al  Recyling aluminium hydroxide

 Bayer Process: Refining Bauxite

 Scrap recycling  The scrap is cleaned and sorted  If the scrap contains more than 20% Al by wt. Aluminum hydroxide  It is a waste from Al production and can be assumed as free of impurities  It is then Calcined directly

 To produce 1kg of aluminum,  5,900kg earth has to mined  5.1kg Bauxite,  1.93kg alumina and  0.45kg carbon anode  This means that for 2010 annual world production of 41.1 million tons aluminum,  210 million tons of bauxite,  80 million tons of alumina and  21 million tons of carbon anode

 On the basis of 1kg aluminum Source: Wang et al.2012 Bayer process

 Al from recycled Al(OH) 3, Scrap recycling Source: Wang et al.2012 Requires only 43% total energy of primary Al prod. If Scrap contains >20% Al (wt.)

 Wang H., Leung D.Y.C, Leung M.K.H, 2012, Energy analysis of hydrogen and electricity production from aluminum-based processes, Applied energy 90,  U.S. Department of energy, U.S. Energy requirement for aluminum production: historical perspective, theoretical limits and current practices, February 2007  Totten G.E, Mackenzi D.S., 2003, Handbook of Aluminum, Vol 1,Physical Metallurgy and processes, Marcel Dekker, Inc, USA