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SUBSTITUTION OF TOPAZ,DOMESTIC KYANITE,AND SYNTHETIC MULLITE-CORUNDUM FOR INDIA KYANITE: IV,RAW TOPAZ AS HIGH-TEMPERATURE BOND FOR DOMESTIC KYANITE* |
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| Authors: | T N McVay W W Galbreath Jr Dan Allen |
| Affiliation: | 1. The Electrotechnical Laboratory Bureau of Mines Norris, Tennessee;2. The Electrotechnical Laboratory Bureau of Mines Norris, Tennessee
The authors are, respectively, senior mineralogist, Southern Experiment Station, in charge of the Refractories Section at Norris, Tenn.;3. junior ceramic engineer, and junior physical science aide, Electrotechnical Laboratory, Bureau of Mines, U. S. Department of the Interior, Norris, Tenn. |
| Abstract: | Raw topaz has been found to act as a high-temperature bond for both raw and calcined kyanite. It is thought that this bonding action is due in part to volatiles which emerge from the raw topaz between 1000° and 1200°C. Some of the topaz decomposition products are absorbed and retained by the calcined kyanite. Within the limits of this investigation, all refractories which contained either calcined or raw kyanite, or mixtures of the two, with a minimum of 10% raw topaz had a good structure and were well bonded. The results of the load tests indicated that increased firing temperatures in the preheat improved the load resistance, but excellent high-temperature resistance was obtained by preheating as low as 1300°C. in laboratory kilns. |
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