One-step fabrication of hollow aluminosilicate microspheres with a composite zeolite/glass crystalline shell

Vereshchagina, T. A.; Верещагин, С. Н.; Shishkina, N. N.; Mikhaylova, Olga A.; Solovyov, Leonid A.; Anshits, A. G.

doi:10.1016/j.micromeso.2012.11.010

Cited by 33 publications

(21 citation statements)

References 23 publications

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“…53 As a result, the cenospheres have an additional advantage in the development of functional materials, such as microspherical membranes, 15,16 composite sorbents, 18,19 and supported catalysts. 23 Table 4.…”

Section: Energy and Fuelsmentioning

confidence: 99%

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

et al. 2015

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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 Al 2 O 3 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 SiO 2 /Al 2 O 3 = 4.34 − 0.08[Al 2 O 3 ] 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 Al 2 O 3 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 singlering 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 Al 2 O 3 content from 43 wt % to 51 wt % and can be described by the regression equation SiO 2 /Al 2 O 3 = 2.71 − 0.04[Al 2 O 3 ] 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 Al 2 O 3 content from 26 wt % to 42 wt % and can be described by the general regression equation SiO 2 /Al 2 O 3 = 4.71− 0.09[Al 2 O 3 ] 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. ■ INTRODUCTIONIn the process of generating power from coal, large quantities of coal combustion products (CCPs) are produced. According to the various estimates, combustion of coal in the Russia alone generates ∼25 million tons of CCPs per year but utilization rate does not exceed 15%. 1 The complex composition of CCPs, including the fly ash, has proven to be a barrier to its bulk utilization in many fields. Extraction of concentrates of microspherical components with specific characteristics from fly ashes of variable composition provides wider opportunities for the multicomponent use of fly ashes produced from coal combustion. 2,3 The unique properties of cenospheres, namely, their low density, sphericity of particles, and high strength and nontoxicity, make them useful for a variety of fields of applications. Thus, concentrates of cenospheres are used as fillers of lightweight composite materials, such as concretes, 4,5 polymers and resins, 6−8 and metal alloys. 9,10 Also, they are been studied for the production of ceramic composite foams with different properties. 11,12 In recent years, new functional materials have been developed based on a d...

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Section: Energy and Fuelsmentioning

confidence: 99%

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

et al. 2015

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“…Most microspheres are made from rigid shell materials such as polymeric materials, ceramic, glass [15][16][17][18][19] to obtain excellent end properties. Most kinds of macrospheres have limitations because of their low compressive strength or their high density.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of three phase epoxy syntactic foam filled with carbon fiber reinforced hollow epoxy macrospheres and hollow glass microspheres

Dong

Zhang

et al. 2014

Polymer Composites

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The present study focuses on the preparation and characterization of three phase epoxy syntactic foam (ESF) filled with carbon fiber reinforced hollow epoxy macrospheres (CFR-HEMS) and hollow glass microspheres (HGMS). The ESF was produced by embedding CFR-HEMS into a mixture of epoxy-hardener and 30 wt% HGMS. An innovative approach and simple procedure was implemented in the preparation of CFR-HEMS where expanded polystyrene (EPS) beads were used as initiation template. The EPS beads were coated with epoxy resin and carbon fiber using "rolling ball method," and these coated EPS beads were later cured and postcured at high temperature which will shrink the EPS beads thus producing a hollow macrosphere structure. The compressive property of ESF was characterized and the mechanical model was issued. The ESF (450 kg/ m 3

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“…This can be achieved more easily with glassy materials, because their viscosity progressively evolves with temperature. Therefore, the feedstock should be initially glassy, semi-crystalline or a glass-crystal composite [28]. A totally crystalline feedstock (Fig.…”

Section: Structure Of Slags and Their Ability To Produce Hollow Micromentioning

confidence: 99%

Formation of hollow vitreous and semi-crystalline microspheres in slag flame spraying

Poirier

Quercia

2015

Ceramics International

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One-step fabrication of hollow aluminosilicate microspheres with a composite zeolite/glass crystalline shell

Cited by 33 publications

References 23 publications

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

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

Preparation and characterization of three phase epoxy syntactic foam filled with carbon fiber reinforced hollow epoxy macrospheres and hollow glass microspheres

Formation of hollow vitreous and semi-crystalline microspheres in slag flame spraying

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