Characterization of Fly Ash Cenospheres Produced from the Combustion of Ekibastuz Coal

Тип публикации: статья из журнала

Год издания: 2015

Идентификатор DOI: 10.1021/acs.energyfuels.5b01022

Ключевые слова: Coal combustion, Fly ash, Kaolinite, Mullite, Nanotechnology, Regression analysis, Shells (structures), Silicate minerals, Structure (composition), Chemical compositions, Correlation coefficient, Fly ash cenospheres, Individual particles, Nano-scale surfaces, Regression equation, Single-ring structures, Thermal conversion, Aluminum

Аннотация: The relationship between the chemical composition and shell structure of cenospheres with a low bulk density of 0.40-0.45 g/cm(3) and a high Al2O3 content of 33-38 wt % has been systematically studied. It was established that the composition of the narrow fractions of cenospheres can be described by the general regression equation SiO2/Al2O3 = 4.34 0.08[Al2O3] with the correlation coefficient of r = -0.99. The phase composition includes the glass phase (57-73 wt %), mullite (25-40 wt %), and quartz (1.2-2.5 wt %). An increase in the Al2O3 content leads to an increase in the size of particles and the porosity of their shells. In the obtained fractions of cenospheres, there are two types of globules: spherical globules with a single-ring structure and foamy globules with a network structure. It is established that the composition of individual particles with a network structure localized in the range of the Al2O3 content from 43 wt % to 51 wt % and can be described by the regression equation SiO2/Al2O3 = 2.71 - 0.04[Al2O3] with the correlation coefficient of r = 0.97. The framework of these particles permeated by mullite microcrystallites and coated with a nanoscale surface film. The structure-forming mineral precursor of these particles is kaolinite. The gross composition of the shell of individual globules with a single-ring structure localized in the range of the Al2O3 content from 26 wt % to 42 wt % and can be described by the general regression equation SiO2/Al2O3 = 4.71 - 0.09[Al2O3] with the correlation coefficient of r = -0.98. The outer and inner surfaces of the shell are covered by large and small in-plane localized mullite crystals hidden by the nanoscale film. The spherical shape and their crystalline framework are formed from the illite melt with inclusions of products of the thermal conversion of other mineral forms.

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Издание

Журнал: ENERGY & FUELS

Выпуск журнала: Vol. 29, Is. 8

Номера страниц: 5390-5403

ISSN журнала: 08870624

Место издания: WASHINGTON

Издатель: AMER CHEMICAL SOC

Авторы

  • Fomenko E.V. (Institute of Chemistry and Chemical Technology)
  • Anshits N.N. (Institute of Chemistry and Chemical Technology)
  • Vasilieva N.G. (Institute of Chemistry and Chemical Technology)
  • Mikhaylova O.A. (Institute of Chemistry and Chemical Technology)
  • Rogovenko E.S. (Institute of Chemistry and Chemical Technology)
  • Zhizhaev A.M. (Institute of Chemistry and Chemical Technology)
  • Anshits A.G. (Siberian Federal University)

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