Effect of Precursor Raw Materials on the Structure of Fused Alumomagnesian Spinel

Results for aluminomagnesian spinel prepared by fusing periclase from natural magnesite and alumina at 30.5-32.5% MgO are reported. The structure of solidified melt is similar to that of eutectic; the role of impurities and nonequilibrium crystallisation conditions is discussed. Spinel crystals with...

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Bibliographic Details
Published in:Refractories and industrial ceramics 2003-11, Vol.44 (6), p.405-410
Main Authors: Maryasev, I G, Koptelov, V N, Dmitrienko, Yu A, Kaplan, F S, Koreshkova, M Yu
Format: Article
Language:English
Subjects:
Alkalis
Concentration (composition)
Heating
Impurities
Interstitials
Raw materials
Solid solutions
Spinel
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Summary:Results for aluminomagnesian spinel prepared by fusing periclase from natural magnesite and alumina at 30.5-32.5% MgO are reported. The structure of solidified melt is similar to that of eutectic; the role of impurities and nonequilibrium crystallisation conditions is discussed. Spinel crystals with a composition close to stoichiometric and iron-in-periclase solid solutions formed. Impurities in the form of a low-melting glass containing up to 20% of alkalis and merwinite concentrated in the interstitial space of the two phases. The structure thus produced cannot be considered as optimum because the liquid phase that forms in the crystalline phase at relatively low heating temperatures will adversely affect the high-temperature strength and corrosive resistance of the material. For this reason, development of methods that would allow preparation of a high-quality fused spinel from inexpensive raw materials and allow control over the distribution of impurities in spinel solid solutions remains a challenging problem. 13 refs.
ISSN:1083-4877
1573-9139
DOI:10.1023/B:REFR.0000016779.02545.4c