Structure–Composition Relationship of Skeletal and Dendritic Ferrospheres Isolated from Calcium-Rich Power Plant Ash

Abstract

This paper presents a systematic SEM–EDS study of polished sections of individual skeletal and dendritic ferrospheres in the–0.04 + 0.032 mm size fraction, isolated from fly ash from the combustion of brown coal from the Berezovskoe field. The ferrospheres are characterized by a wide range of variations in the macrocomponent composition of local areas. We have identified groups of globules whose overall composition as well as the composition of local areas on their polished sections can be represented by general equations for component concentrations: SiO2 = f(FeO), SiO2 = f(Al2O3), and CaO = f(SiO2). Such equations make it possible to identify the nature of the mineral precursors involved in the formation of the globules. FeO-rich skeletal ferrospheres with low CaO concentration originate from the thermochemical transformation of pyrite and illite associates. Skeletal and dendritic ferrospheres with monotonically increasing CaO and SiO2 concentrations are formed from pyrite and montmorillonite associates, with the participation of a melt containing quartz and decomposition products of Ca-humates of the initial coal. Skeletal and dendritic spinel ferrite crystallization is due to a magnesium aluminate spinel “seed,” resulting from the thermal transformation of illite and montmorillonite from the parent coal. The observed increase in glass phase concentration and the change from the skeletal type of crystallization to a dendritic in the ferrospheres containing ≤64 wt % FeO and ≥6.5 wt % CaO are due to the low concentration of the spinel-forming cations Fe2+ and Fe3+ in the melt and the increase in the percentage of [Fe3+O2] and [Fe23+ O5]4− ferrite complexes with an increase in the degree of oxidation of the melt.

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References

  1. 1.

    Kizil’shtein, L.A., Dubov, I.V., Shpitsgluz, A.L., and Parada, S.P., Komponenty zol i shlakov TES (Components of Power Plant Ash and Slag), Moscow: Energoatomizdat, 1995.

    Google Scholar 

  2. 2.

    Vassilev, S.V., Menendez, R., Borrego, A.G., Diaz-Somoano, M., and Martinez-Tarazona, M.R., Phasemineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 3. Characterization of magnetic and char concentrates, Fuel, 2004, vol. 83, pp. 1563–1583.

    CAS  Article  Google Scholar 

  3. 3.

    Sharonova, O.M., Anshits, N.N., Solovyov, L.A., Salanov, A.N., and Anshits, A.G., Relationship between composition and structure of globules in narrow fractions of ferrospheres, Fuel, 2013, vol. 111, pp. 332–343.

    CAS  Article  Google Scholar 

  4. 4.

    Sharonova, O.M., Anshits, N.N., and Anshits, A.G., Composition and morphology of narrowly sized ferrospheres isolated from various types of fly ash, Inorg. Mater., 2013, vol. 49, no. 6, pp. 586–594.

    CAS  Article  Google Scholar 

  5. 5.

    Bayukov, O.A., Anshits, N.N., Petrov, M.I., Balaev, A.D., and Anshits, A.G., Composition of ferrospinel phase and magnetic properties of microspheres and cenospheres from fly ashes, Mater. Chem. Phys., 2009, vol. 114, no. 1, pp. 495–503.

    Article  Google Scholar 

  6. 6.

    Sharonova, O.M., Anshits, N.N., Fedorchak, M.A., Zhizhaev, A.M., and Anshits, A.G., Characterization of ferrospheres recovered from high-calcium fly ash, Energy Fuels, 2015, vol. 29, pp. 5404–5414.

    CAS  Article  Google Scholar 

  7. 7.

    Sokol, E.V., Kalugin, V.M., Nigmatulina, E.N., Volkova, N.I., Frenkel, A.E., and Maksimova, N.V., Ferrospheres from fly ashes of Chelyabinsk coals: chemical composition, morphology and formation conditions, Fuel, 2002, vol. 81, no. 7, pp. 867–876.

    CAS  Article  Google Scholar 

  8. 8.

    Ramsden, A.R. and Shibaoka, M., Characterization and analysis of individual fly-ash particles from coalfired power stations by a combination of optical microscopy, electron microscopy and quantitative electron microprobe analysis, Atmos. Environ., 1982, vol. 16, no. 9, pp. 2191–2206.

    CAS  Article  Google Scholar 

  9. 9.

    Blaha, U., Sapkota, B., Appel, E., Stanjek, H., and Rösler, W., Micro-scale grain-size analysis and magnetic properties of coal-fired power plant fly ash and its relevance for environmental magnetic pollution studies, Atmos. Environ., 2008, vol. 42, no. 36, pp. 8359–8370.

    CAS  Article  Google Scholar 

  10. 10.

    Kutchko, B.G. and Kim, A.G., Fly ash characterization by SEM–EDS, Fuel, 2006, vol. 85, pp. 2537–2544.

    CAS  Article  Google Scholar 

  11. 11.

    Sharonova, O.M., Solovyov, L.A., Oreshkina, N.A., Yumashev, V.V., and Anshits, A.G., Composition of high-calcium fly ash middlings selectively sampled from ash collection facility and prospect of their utilization as component of cementing materials, Fuel Process. Tech., 2010, vol. 91, no. 9, pp. 573–681.

    CAS  Article  Google Scholar 

  12. 12.

    Shpirt, M.Ya., Kler, V.R., and Pertsikov, I.Z., Neorganicheskie komponenty tverdykh topliv (Inorganic Components of Solid Fuels), Moscow: Khimiya, 1990.

    Google Scholar 

  13. 13.

    Bryers, R.W., Fireside slagging, fouling, and high-temperature corrosion of heat-transfer surface due to impurities in steam-raising fuels, Prog. Energy Combust. Sci., 1996, vol. 22, no. 1, pp. 29–120.

    CAS  Article  Google Scholar 

  14. 14.

    Lebedev, I.K., Zavorin, A.S., and Karyakin, S.K., Thermoanalytical study of the mineral component of coal fractions from the Berezovskoe field, Khim. Tverd. Tela, 1973, no. 5, pp. 38–42.

    CAS  Google Scholar 

  15. 15.

    Zhao, Y., Zhang, J., and Zheng, C., Transformation of aluminum-rich minerals during combustion of a bauxite- bearing Chinese coal, Int. J. Coal Geol., 2012, vol. 94, pp. 182–190.

    CAS  Article  Google Scholar 

  16. 16.

    Berezhnoi, A.S., Mnogokomponentnye sistemy okislov (Multicomponent Oxide Systems), Kiev: Naukova Dumka, 1970.

    Google Scholar 

  17. 17.

    Esin, O.A. and Gel’d, P.V., Fizicheskaya khimiya pirometallurgicheskikh protsessov (Physical Chemistry of Pyrometallurgical Processes), Moscow: Metallurgiya, 1966, 2nd ed., part 2.

    Google Scholar 

  18. 18.

    Zhuravlev, G.I., Khimiya i tekhnologiya ferritov (Chemistry and Technology of Ferrites), Leningrad: Khimiya, 1970.

    Google Scholar 

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Correspondence to A. G. Anshits.

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Original Russian Text © N.N. Anshits, M.A. Fedorchak, A.M. Zhizhaev, A.G. Anshits, 2018, published in Neorganicheskie Materialy, 2018, Vol. 54, No. 3, pp. 275–283.

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Anshits, N.N., Fedorchak, M.A., Zhizhaev, A.M. et al. Structure–Composition Relationship of Skeletal and Dendritic Ferrospheres Isolated from Calcium-Rich Power Plant Ash. Inorg Mater 54, 253–260 (2018). https://doi.org/10.1134/S0020168518030032

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Keywords

  • skeletal and dendritic ferrospheres
  • formation paths