Paper Title:
Control and Removal of Impurities from Al Melts: A Review
  Abstract

Control of impurity elements in Al-based alloys is of increasing technological importance, both in primary and secondary alloy production. In primary alloy production, Ni and V concentrations in the coke are rising and this is increasing the level of impurities in the final products to the extent that they are out of specification. Impurity control is also of concern in recycling due to the pickup of elements such as Fe from contaminants in the scrap, which can detrimentally affect the alloy properties. Dissolved elemental impurities can be removed by a number of different processes including boron treatment for some of the transition metals. Other processes in the cast shop for removing impurities and inclusions from Al melts include fluxing, floatation, and filtration. Gas purging, vacuum treatment, filtration, the use of salts, and combinations of these presently find commercial applications. Ultra purity Al and its alloys can be obtained using zone refining and three-layer electrolysis methods. The demand for higher purity Al has been largely met by additional electrolytic refining processes. This paper reviews the tools that are currently available to the casthouse for removing impurities and inclusions from Al melts and suggests approaches that may be useful to meet future challenges.

  Info
Periodical
Chapter
Chapter 5: Melt Quality and Treatment
Edited by
A.Prasad, J.A. Taylor and J.F. Grandfield
Pages
149-160
DOI
10.4028/www.scientific.net/MSF.693.149
Citation
M. A. Dewan, M.A. Rhamdhani, J. B. Mitchell, C. J. Davidson, G. A. Brooks, M. Easton, J. F. Grandfield, "Control and Removal of Impurities from Al Melts: A Review", Materials Science Forum, Vol. 693, pp. 149-160, 2011
Online since
July 2011
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Price
$32.00
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