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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/220551
- Melt quality and management of raw material impurities in cast house
- Grandfield, John F.; Khaliq, Abdul; Rhamdhani, Akbar; Dewan, Mohamad; Easton, Mark; Sweet, Lisa; Davidson, Cameron; Mitchell, Jason; Brooks, Geoffrey A.
- It is apparent that the concentrations of impurities in raw materials (particularly petroleum coke) are increasing with significant implications for melt quality and the ability of cast houses to meet customer chemical specifications. A large fraction of the metal content of the coke and alumina reports to the aluminium in the reduction cells. In some smelters the concentration of these impurities is beginning to exceed customer cast product specifications. Nickel and vanadium are of particular concern. These impurities can have detrimental effects in certain alloys, however for many systems it is not clear if the maximum specifications arise from known detrimental effects or are simply set from what was achievable historically. This paper recaps what is known about the effect of dissolved metals on alloy properties and discusses cast house and other management strategies along the value chain for coping with these changes. Options include; improved Bayer plant operations, segregated anode production, impurity removal during dry scrubber operations, melt treatment before casting to remove these impurities and adjustment of specifications following expensive property testing. Aluminium boride treatment can be used to remove vanadium however the process is slow and only used at present on electrical conductivity grade material. Some current work on the mechanisms of this process is examined to get a picture of the possibility of speeding up the process. Potential for development of a melt nickel removal process is considered and some preliminary results presented. The cost of establishing new specifications is examined. The need for an integrated strategy across the supply chain is highlighted.
- Publication type
- Conference paper
- Research centre
- Swinburne University of Technology
- Paper presented at the 10th Australasian Aluminium Smelting Technology Conference, Launceston, Tasmania, Australia, 09-14 October 2011
- Publication year
- Alumina; Boride treatment; Filtration; Gallium; Impurities; Melt quality; Nickel; Petroleum coke; Vanadium
- University of New South Wales
- Publisher URL
- Copyright © 2011.
- Additional information
- The CAST Co-operative Research Centre was established, and is funded in part, by the Australian Governments Co-operative Research Centre Program.
- Peer reviewed