Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-27T02:18:16.451Z Has data issue: false hasContentIssue false

Speciation in Size and Density Fractionated Fly Ash

Published online by Cambridge University Press:  25 February 2011

Raymond T. Hemmings
Affiliation:
Ontario Research Foundation, Sheridan Park, Mississauga, Ontario L5K 1B3
Edwin E. Berry
Affiliation:
E.E. Berry and Associates, P. O. Box 6662, Stn. J., Ottawa, Ontario K2A 3Y7
Get access

Abstract

Morphological, chemical and mineralogical speciation of fly ash from a power plant burning sub-bituminous coal has been investigated by examination of size and density fractions. It was found that whereas, fractionation by size revealed little information as to speciation among particle types, separation of the ash into six density fractions showed major differences in properties associated with true particle density. In particular it was found that at least two types of glass co-exist in the ash: “Glass I” – a predominantly silico-aluminous glass associated with particles of low density (cenospheres); “Glass II” – a calcium alumino-silicate glass associated with high-density particles. These glasses were found to differ greatly in composition and to be characterized by shifts in the position of the 2-theta of the XRD-halo. In addition, it was shown that cryptocrystalline mullite is associated only with the low-density particles. It is proposed that particles comprising low-density fractions can be considered as glassceramics with low degrees of crystallization. Particles of high-density are better described as the products of internal lime-sinter reactions.

Type
Articles
Copyright
Copyright © Materials Research Society 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Roode, M. van, and Hemmings, R. T., CANMET Contract Report, No. ISQ83-00162, July 1985.Google Scholar
2. Grimshaw, R. W., The Chemistry and Physics of Clays, 4th Ed., Ernest Benn Ltd. London, p. 269 (1971).Google Scholar
3. Watt, J. D. and Thorne, D. J., J. Appl. Chem., 15, 585594 (1965).Google Scholar
4. Carpenter, R. L., Clark, R. D. and Su, Yin-Fong, J. Air Pollution Control Assoc., 30, 679681 (1980).Google Scholar
5. Campbell, D. E. and Hagy, H. E., “Glasses and Glass-ceramics”, in CRC Handbook of Materials Science, Vol II: Metals, Composites and Refractory Materials, Edited by Lynch, C. T. (CRC Press, Inc., Boca Raton, FL, 1975).Google Scholar
6. Fisher, G. L., Prentice, B. A., Silberman, D., Ondov, J. M., Biermann, A. H., Ragaini, R. C. and McFarland, A. R., Env. Sci. Technol., 12, 447451 (1978).Google Scholar
7. Lauf, R. J., Am. Ceramic Soc. Bull., 61, 487490 (1982).Google Scholar
8. Hulett, L. D., Weinberger, A. J., Ferguson, N. M., Northcutt, K. J. and Lyon, W. S., Trace Element and Phase Relations in Fly Ash, EPRI Report, EA-1822, May 1981.Google Scholar
9. Raask, E., J. Inst. Fuel, 41, 339344 (1968).Google Scholar
10. McClung, J. D. and Geer, M. R., in “Coal Preparation”, Edited Leonard, J. W., (Am. Inst. Min. Met. and Pet. Eng., New York, New York, 4th Edn., 1979).Google Scholar
11. Hubbard, F. H., McGill, R. J., Dhir, R. K. and Ellis, M. S., Min. Mag., 48, 251256 (1984).Google Scholar
12. Carrier, G. B., J. Am. Ceram. Soc., 47, 365367 (1964).Google Scholar
13. Diamond, S. D., Cem. Conc. Res., 13, 459464 (1983).Google Scholar
14. Mehta, P. K., Cem. Conc. Res., 15, 669674 (1985).Google Scholar
15. Canon, R. M., Gillian, T. M. and Watson, J. S., Evaluation of Potential Processes for Recovery of Metals from Coal Ash - Volume 1, EPRI Report CS-1992, Volume 1, August 1981.Google Scholar