Transcript ALUMINIUM
Australian Aluminium Teacher Guide Some links may not work on the web version Please see in class for details Mr G http://www.aluminium.org.au/Page.php?d= 1020 List all six Boyne Island List facts Boyne Smelters Limited at Boyne Island, Queensland was commissioned in 1982 with a two-potline capacity of 206,000 tonnes per year. The third potline was added in 1997 Increasing production capacity to 490,000 tonnes. Further improvements have seen current production reach 545,000 tonnes per annum (2006), making BSL Australia's largest aluminium smelter. Aluminium ingot, t-bar and billet are produced at the Boyne Island smelter. http://www.comalco.com/ Aluminium production starts with the BAYER process. This extracts aluminium oxide (alumina) from bauxite (aluminium ore) The alumina (aluminium oxide) is then dissolved in cryolite. Once dissolved, the final process of metal extraction involves ELECTROLYSIS BAYER PROCESS ANIMATION REQUIRES INTERNET CONNECTION HERE http://www.qal.com.au/Environment_Management. html How does QAL care for the environment once the bauxite has been mined? After the bauxite has been mined, processed and environment restored. The alumina is transported to the smelter for metal extraction Aluminium Smelting Process http://www.alcoa.com/australia/en/info_page/Smelting_Process .asp Alumina is made up of aluminium and oxygen. To produce aluminium metal, these two elements need to be separated. Two tonnes of alumina are needed to make one tonne of aluminium. Alumina is dissolved in an electrolytic bath of molten cryolite (sodium aluminium fluoride) within a large carbon or graphite lined steel furnace known as a ‘pot’. There are hundreds of pots at a typical smelter. A high electric current is passed through the pot at low voltage, via carbon blocks called anodes. The strong electric current flows continuously from the anode (positive), through the alumina/cryolite mixture to the carbon or graphite lining of the pot (negative), and then to the next pot, and so on. The electricity enables the alumina to split into its components of aluminium and oxygen. The oxygen bubbles away and the aluminium settles to the bottom of the pot. The electricity also maintains the temperature of the process at about 950 degrees Celsius. The molten aluminium is cast at a temperature of just over 700 degrees Celsius to form ingots. Hall Heroult process COPY http://image.tutorvista.com/content/p-block-elements/hall-heroultprocess.jpeg http://ibchem.com/IB/ibfiles/options/opt_E/ope_img/c ell.jpg