Bulk and Surface Studies of Fly Ash Particles

Boni, C.; Cereda, E.; Marcazzan, G.; Parmigiani, F.

doi:10.1007/978-1-4615-1827-3_11

Cited by 5 publications

(5 citation statements)

References 38 publications

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“…The characteristics of fly ashes may vary significantly depending on their origin, ,−,− and in order to obtain a better understanding of the properties of these materials and the capture of Hg, this research is focused on the establishment of relationships between Hg retention, fly ash carbons, and their textural properties for anthracite-derived fly ashes, which have been the least studied ashes, and for which almost no data have been reported. This work is also a continuation of a previous research study 21-22 in which the various organic and inorganic fly ash components were classified via optical microscopy and a relationship between the carbon content and Hg retention was established.…”

Section: Introductionmentioning

confidence: 99%

Relationship between Textural Properties, Fly Ash Carbons, and Hg Capture in Fly Ashes Derived from the Combustion of Anthracitic Pulverized Feed Blends

and

Parra

2007

Energy Fuels

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In this work, the textural properties of a series of whole anthracitic-derived fly ashes sampled in eight hoppers from the electrostatic precipitators and their sized fractions (from >150 to <25 μm) are investigated. Data from N2 adsorption isotherms at 77 K, helium density, and mercury porosimetry have contributed to establish a relationship between the Brunauer−Emmett−Teller (BET) surface areas, V TOT, porosity, carbon content (the type of fly ash carbons), and Hg retention in these fly ashes. The unburned carbons in these ashes are macroporous materials, and they are different from the carbons in fly ashes from classes C and F (the latter derived from the combustion of bituminous coals) and show different textural properties. These ashes represent the end member of the fly ash classes C and F with respect to certain textural properties. Although the BET surface area and V TOT values for the studied samples are the lowest reported, they increase with the increase in carbon content, anisotropic carbon content, and particle size of the ashes. Thus, a positive relationship between all these parameters and Hg capture by the coarser ash fractions was found. The finest fraction of carbons (<25 μm) represented an exception. Although it makes a significant contribution to the total carbon of the whole fly ashes and shows relatively higher surface areas and V TOT values, its Hg concentration was found to be the lowest. This suggests that the type of unburned carbons in the finest fraction and/or other adsorption mechanisms may play a role in Hg concentration. Because the textural properties of anisotropic carbons depend on their subtype and on their origin, the need for its differentiation has been evidenced.

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Section: Introductionmentioning

confidence: 99%

Relationship between Textural Properties, Fly Ash Carbons, and Hg Capture in Fly Ashes Derived from the Combustion of Anthracitic Pulverized Feed Blends

and

Parra

2007

Energy Fuels

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“…Therefore, it is important to determine what general chemical and physical properties can be expected of carbons separated from a variety of fly ashes using a number of separation processes. It has already been shown that the properties of fly ashes can vary significantly based upon their origin. , …”

Section: Introductionmentioning

confidence: 99%

“…It has already been shown that the properties of fly ashes can vary significantly based upon their origin. 19,20 A general understanding of the properties of unburned carbon can be somewhat assembled from several studies focusing on its specific properties and behavior. [21][22][23][24][25] Those studies have usually focused on characterization of the properties of a limited number of ash-derived carbons, or only a few characterization methods have been employed in a given study.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Carbon Concentrates from Coal-Combustion Fly Ash

et al. 2001

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A study of carbon concentrates separated by a number of different commercial and laboratory methods from various coal-combustion fly ashes was undertaken to determine what common and unique chemical and physical properties can be expected in such concentrates. The properties were determined using a variety of physical and spectroscopic characterization methods and then were compared among the carbon concentrates and in two cases with the properties of the unprocessed fly ashes. The class F fly ashes originated from a total of seven different utilities burning bituminous coals and underwent one of six different processing methods to produce the carbon concentrates, which contained from 24% to 76% carbon. Three different configurations of triboelectrostatic separators were used to produce the carbon concentrates in addition to two different flotation methods plus a proprietary carbon recovery process. The results showed that unburned carbon concentrates from fly ash have properties similar to most carbon blacks and would be poor replacements for activated carbon in adsorption processes unless they are activated in a separate step. The untreated carbon may have applications as a substitute for carbon black provided it could be obtained in sufficient purity. The results have implications for those who wish to use carbon concentrates from coal-combustion fly ashes in secondary markets, especially as sorbents and fillers.

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“…The Fly-ash is a waste and could pollute the environment without any process [1,2,3,4]. Test results of the Fe-rich hollow cenosphere show that it is a kind of dielectric loss material [5,6,7] which can be used to design structural absorber.…”

Section: Introductionmentioning

confidence: 99%

Design and optimize spherical particle absorber by Fe-rich hollow cenosphere of fly-ash for broadband electromagnetic wave absorbing wall

Tang

Wang

et al. 2015

IEICE Electron. Express

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In this paper, the absorbing effectiveness of spherical particle absorber made of cheap Fe-rich hollow cenosphere fly-ash is analyzed. The effects of the diameter of spheres, the number of layer and the stack modes of sphere particle on the absorbing effectiveness were explored. Based on the results, a three-layer structure with mixed sizes of spheres was designed, constructed and tested. Obtained results show that this structure has a maximal reflection loss of 9 dB and the bandwidth being higher than 5 dB is more than 17 GHz. When applying the permittivity of Fe-rich hollow cenosphere fly-ash, and the thickness of absorber is 6.5 cm, the maximal reflection loss is 23 dB and the bandwidth being lower than −10 dB is more than 14 GHz, which covers the C, X and Ku bands. The experimental test proved that the three-layer structure absorber has good absorbing effectiveness.

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Bulk and Surface Studies of Fly Ash Particles

Cited by 5 publications

References 38 publications

Relationship between Textural Properties, Fly Ash Carbons, and Hg Capture in Fly Ashes Derived from the Combustion of Anthracitic Pulverized Feed Blends

Relationship between Textural Properties, Fly Ash Carbons, and Hg Capture in Fly Ashes Derived from the Combustion of Anthracitic Pulverized Feed Blends

Characterization of Carbon Concentrates from Coal-Combustion Fly Ash

Design and optimize spherical particle absorber by Fe-rich hollow cenosphere of fly-ash for broadband electromagnetic wave absorbing wall

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