Structure and phase composition of aluminosilicate-based microspheres

The paper focuses on aluminosilicate-based microspheres, whose shell represents an X-ray amorphous state, which significantly reduces their strength properties. However, a number of technological characteristics used in industry provide the formation of glass-ceramic and crystalline states of the condensed phase, which is the shell microsphere. Presently, the formation of the structure and phase composition during the interaction between aluminosilicates (the SiO2/Al2O3 ratio varies between 0−100 %) and high-temperature (≥ 5000 K) plasma is most interesting. This paper presents the research results of the structure and phase composition of the aluminosilicate-based condensed phase during the microsphere production. The X-ray phase analysis shows that after cooling, the structure and phase composition of the microsphere shells based on refractory polycrystalline materials promotes the formation of the X-ray amorphous structure at SiO2 ≥ 60 wt. % in the initial powder and the transition of γ-Al2O3 cryptocrystalline phase to high-temperature α- Al2O3 phase with the use of the initial alumina powder.

1. Hanifa Asad, Lu Zeyu, Li Zongjin. Utilization of fly ash cenosphere as lightweight filler in cement- based composites A review. Construction and Building Materials. 2017. V. 144. No. 30. Pp. 373–384.

2. Perfilov V.A., Kotlyarevskaya A.V., Kanavets U.V. Vliyanie polykh steklyannykh mikrosfer na svoistva legkikh melkozernistykh betonov [Influence of hollow glass microspheres on light finegrained concrete properties]. Vestnik Volgogradskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. Seriya: Stroitel'stvo i arkhitektura. 2016. No. 43 (62). Pp. 93–103. (rus)

3. Navid R., Carsten K. Cenospheres: A review. Fuel. 2017 V. 207. No. 1. Pp. 1–12.

4. Inozemtsev A.S., Korolev E.V. Deformatsii vysokoprochnykh legkikh betonov na polykh mikrosferakh i sposob ikh snizheniya [Deformation of high-strength lightweight concretes on hollow microspheres and method of deformation reduction]. Stroitel'nye materialy. 2015. No. 5. Pp. 23−30. (rus)

5. Kornienko E.E., Lapushkina E.J., Kuzmin V.I. Air plasma sprayed coatings of self-fluxing powder materials. Journal of Physics: Conference Series. 2014. V. 567. No. 1. P. 012010.

6. Yi Li, Xiangpeng Gao, Hongwei Wu. Further investigation into the formation mechanism of ash cenospheres from an Australian Coal-Fired Power Station. Energy Fuels. 2013. V. 27. No. 2. Pp. 811–815.

7. Shelby J.E. Introduction to glass science and technology. Cambridge: The Royal Society of Chemistry. 2005. 312 p.

8. Vassilev S.V., Menendez R., Diaz-Somoano M., Martinez-Tarazona M.R. Phase-mineral and chemical composition of coal fly ashes as a basis for their multicomponent utilization. 2. Characterization of ceramic cenosphere and salt concentrates. Fuel. 2004. V. 83. Pp. 585–603.

9. Donskoi A.V., Klubnikin V.S. Elektroplazmennye protsessy i ustanovki v mashinostroenii [Plasma processes and plants in mechanical engineering]. Leningrad: Mashinostroenie, 1979. 221 p. (rus)

10. Li G.W. Li L.T.W., Tian Z. C., et al. General and facile method to prepare uniform gammaalumina hollow microspheres from waste oil shale ash. Materials Letters. 2014. V. 133. Pp. 143–146.

11. Vakalova T.V., Khabas T.A., Revva I.B., Pavlova I.A. Heat-insulating ceramics which have a nanoporous structure and are made with the use of ash-bearing wastes from power plants. Refractories and Industrial Ceramics. 2015. V. 55. No. 6. Pp. 505–510.

12. Maciej Z., Rui C.N., Luis F.S., Karol W. Characterization of fly-ash cenospheres from coalfired power plant unit. Fuel. 2016. V. 174. Pp. 49–53.