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Material & energy requirements. Production of Aluminum. Technical University of Crete Mining Department of Mineral Resources Engineering Metalurgical Processes – Prof. Komnitsas Athanasios Paraschos 2007020037. Introduction.
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Material & energy requirements Production of Aluminum Technical University of Crete Mining Department of Mineral Resources Engineering Metalurgical Processes – Prof. Komnitsas AthanasiosParaschos 2007020037
Introduction • Aluminum is a light metal with density of 2.7g/cm3 (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
Introduction Worldwide Aluminum production in 2010 Source http://www.alueurope.eu/?page_id=1509
Introduction • 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 20261 billion kilowatt hours • Therefore, • Three percent of the total electrical supply goes to aluminum extraction
Introduction • 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
Production process • Bayer Process: Refining Bauxite
Production process The Hall-Héroult Process: Alumina to Aluminum 2Al2O3 + 3C 4Al +3CO2
Production process • 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
Material requirement • 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
Energy requirement • On the basis of 1kg aluminum Source: Wang et al.2012 Bayer process
Alternative processes • 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.)
references • 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, 100-105 • 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