Carbon bonded magnesia refractories containing aluminum metal are of major importance in the steelmaking industry. The role of natural impurities in the magnesia and graphite constituents in the phase stability of the MgO-C system with metal additions is complex. The objective of this study is to develop a fundamental understanding of the effects of impurity levels and types upon the chemical reaction sequences and resultant phase development within the magnesia-carbon-aluminum system.
Systematic and simulative ranges of the impurity levels were achieved by using four magnesia sinters having purity levels of approximately 96, 97, 98 and 99 wt. % magnesia, and 3 sources of graphite having purity levels of approximately 85, 95 and 99 wt.% carbon. Common oxide impurities found in the magnesia are Al2O3, B2O3, CaO, Fe2O3, and SiO2, and those in the graphite are SiO2, Al2O3, and Fe2O3.
Specimens representing the various impurity levels were prepared and subjected to thermal treatment at temperatures between 700 and 1600 °C in a molybdenum wire wound furnace filled with an argon atmosphere. X-ray diffraction analysis and Scanning Electron Microscopy were used to characterize the composition and morphology of each phase present after treatment at various equilibrium temperatures. Possible reaction mechanisms responsible for the occurring phases are proposed.
Moore, Robert E., 1930-2003
Ramsay, Christopher W.
Guha, Jyoti, P.
Materials Science and Engineering
M.S. in Ceramic Engineering
University of Missouri--Rolla
ix, 55 pages
© 1992 David Alan Cramer, All rights reserved.
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Cramer, David Alan, "Phase stability and reaction sequences of MgO-C-Al refractories: Role of impurities" (1992). Masters Theses. 1056.
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