Recovery potentials of cenospheres from bituminous coal fly ashes

Acar, İlker; Atalay, Mustafa

doi:10.1016/j.fuel.2016.04.013

Cited by 40 publications

(16 citation statements)

References 16 publications

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“…The density of cenospheres varies from 0.2 g/cc up to 2.6 g/cc [22][23][24]. The availability of such low-density (<1 g/cc) cenospheres is quite low, as they constitute a small fraction of about 0.3%-1.5% by weight in fly ash [25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

“…Using water as a medium, cenosphere separation from low-calcium class F fly ash is mostly seen in the literature [22,24,27]. However, for class C fly ash, the use of water for cenosphere separation appears to have become of disadvantageous concern: when mixed with water, the soaked layer rapidly hardens and cannot be used further for other purposes [24].…”

Section: Introductionmentioning

confidence: 99%

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Separation of Cenospheres from Lignite Fly Ash Using Acetone–Water Mixture

2019

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This work reports on the separation of cenospheres from lignite fly ash through a wet separation process-the sink-float method. A better quality of cenospheres could be achieved through a physical–chemical approach using an acetone–water mixture as a medium. This work aimed to elucidate the correlation between the structure, morphology, and composition and medium fraction variables, with data for the freshly prepared and the reused mixtures presented for comparison. The work covers a study of the macrocomponent composition of an Fe2O3–SiO2–Al2O3 system, highlighting the pair dependences of SiO2–Al2O3, Al2O3–Fe2O3, and SiO2/Al2O3–Al2O3 and revealing an interesting result in terms of geochemical characteristics categorizing the collected cenosphere fractions separated from high-calcium class C fly ash produced from a lignite coal power plant in Thailand (as magnetic cenospheres). The CaO and SO3 contents increased monotonically with increased water content, particularly for the CaO composition profile, which was found to be similar to the increased carbonate concentration measured from the mixtures after use. The physicochemical properties in terms of the self-association ability of the acetone–water mixing phase is believed to have played an important role in determining the intermolecular interactions and reactivity of ions in the liquid phase, consequently affecting the separation efficiency, recovery yield, and quality of cenospheres.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Separation of Cenospheres from Lignite Fly Ash Using Acetone–Water Mixture

2019

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“…The policies of the European Union, with new laws and regulations which aim to protect the environment, have led to increased interest in finding new and efficient applications of coal combustion products. Currently, the total annual production of coal fly ash is around 780 million tons worldwide [1], which makes it necessary to carry out detailed studies on its alternative applications [2][3][4]. Cenospheres, present in fly ash, are hollow particles of about 10-1000 µm in diameter, with a density lower than 1 g/cm 3 [5].…”

Section: Introductionmentioning

confidence: 99%

Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

et al. 2019

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Cenospheres from coal fly ashes were used as support in the preparation of Ni–Mg catalysts for dry reforming of methane. These materials were characterized by means of XRD, H2-temperature-programmed reduction (H2-TPR), CO2-temperature-programmed desorption (CO2-TPD), and low-temperature nitrogen sorption techniques. The cenosphere-supported catalysts showed relatively high activity and good stability in the dry reforming of methane (DRM) at 700 °C. The catalytic performance of modified cenospheres was found to depend on both Ni and Mg content. The highest activity at 750 °C and 1 atm was observed for the catalyst containing 30 wt % Mg and 10, 20, and 30 wt % Ni, yielding to CO2 and CH4 conversions of around 95%.

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“…Cenospheres are a by-product, but also one of the more valuable coal combustion products (Ranjba and Kuenze 2017). Most often, cenospheres are spherical and filled with gas (mostly CO 2 and N 2 ) (Li 2012;Pichór 2005;Pichór and Petri 2003;Acar and Atalay 2016;Novoselova et al 2008). Cenospheres are particles of ash with a density lower than the density of water, which facilitates their separation by floatation in sedimentation tanks of power plants (Manocha et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Influence of chemical composition of fly-ash cenospheres on their grains size

Strzałkowska

Adamczyk

2019

Int. J. Environ. Sci. Technol.

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Cenospheres, which are the by-product of hard coal combustion, are characterized by properties allowing for a broad use of this material. The article presents the results of the chemical composition analysis of the cenospheres obtained from various power plants. It has been exhibited that depending on the place of origin, their chemical composition is similar and comparable to fly ash produced in hard coal combustion. A great majority of analysed cenospheres may be classified similarly as the sialic ashes-slightly acidic. The analysis of dependence of refractoriness of the cenospheres on their chemical composition confirmed the correlation between this parameter and the content of SiO 2 and Al 2 O 3. At the same time, the content of each of the chemical components indicates a correlation with the size of the cenospheres. A trend of SiO 2 /Al 2 O 3 ratio decreasing along with the increasing size of the cenospheres has been noted. Also the content of K 2 O and-to a lesser extent-Na 2 O decreases along with increasing diameter of grains. An inverse correlation was noted in case of Fe 2 O 3. The higher the diameter of the grains, the higher the content of this component. In view of the obtained results, it should be assumed that the division of cenospheres into grain-size classes before further industrial use could extent the current range of use of this material.

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Recovery potentials of cenospheres from bituminous coal fly ashes

Cited by 40 publications

References 16 publications

Separation of Cenospheres from Lignite Fly Ash Using Acetone–Water Mixture

Separation of Cenospheres from Lignite Fly Ash Using Acetone–Water Mixture

Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

Influence of chemical composition of fly-ash cenospheres on their grains size

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