A study of calcium hexaluminate
Published online by Cambridge University Press: 14 March 2018
Summary
Calcium hexaluminate has recently been confirmed as a stable phase occurring within the system CaO-Al2O3. In the present investigation, this aluminate has been synthesized from the constituent oxides and its X-ray, optical, and physical (microhardness and reflectivity) properties determined. Similar data have also been obtained on the ferrian phase from the immediate hot-face zone of high-alumina bricks that had been in service in electric arc furnace roofs. An electron-probe microanalysis study revealed that between 12 and 13 % atomic replacement of Al by Fe had occurred in this ferrian calcium hexaluminate. The melting behaviour of the pure compound has been studied by firing pellets in a specially-constructed vacuum furnace. Results show the incongruent melting point to be 1870°C (±10° C), while the liquidus temperature is 1970° C (±10° C). These points were determined by examining polished sections of compacts heated within the range 1820 to 2000° C. A revised phase diagram of the high-alumina portion of the system CaO-Al2O2 is presented.
- Type
- Research Article
- Information
- Mineralogical magazine and journal of the Mineralogical Society , Volume 36 , Issue 281 , March 1968 , pp. 676 - 686
- Copyright
- Copyright © The Mineralogical Society of Great Britain and Ireland 1968
References
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