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

• Published in: Refractories and industrial ceramics Vol. 44; no. 6; pp. 405 - 410
• Main Authors: Maryasev, I G, Koptelov, V N, Dmitrienko, Yu A, Kaplan, F S, Koreshkova, M Yu
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.11.2003
• Subjects: Alkalis; Concentration (composition); Heating; Impurities; Interstitials; Raw materials; Solid solutions; Spinel
• ISSN: 1083-4877; 1573-9139
• DOI: 10.1023/B:REFR.0000016779.02545.4c

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.