Adsorption Isotherms and 13C Solid-state NMR Study of Hazardous Organic Compounds Sorbed on Coal Fly Ash

1997 ◽  
Author(s):  
Daniel A. Netzel ◽  
Francis P. Miknis
Keyword(s):  
Fly Ash ◽  
Organic Compounds ◽  
Coal Fly Ash ◽  
Chemical Properties ◽  
Fly Ashes ◽  
Coal Fly Ashes ◽  
Hazardous Organic Compounds ◽  
Solvent Molecules ◽  
Commercial Applications ◽  
Hematite Fe2o3

Fly ash is a by-product from the combustion of coal. The 1985 annual US production was estimated to be about 1 x 108 metric tons. The utilization of fly ash during the 1980s remained stable at about 25% per year. Because of its pozzolanic properties, nearly 50% of the utilized fly ash is consumed in the production of cement and concrete. The vast quantity of fly ash that is not being used and its availability throughout the country and worldwide have motivated research for new uses in commerce and industry. Little is known of the organic adsorbent properties of fly ash. However, if they are found to be favorable, the potential commercial applications of the adsorptive characteristics of fly ash could include its use as an adsorbent sandwich for organics in combination with landfill or other dump-site liners, in traps for organics in waste waters, in filters for organics in process air streams, and as a stabilizer for organic wastes in drums. Variables that may affect the adsorbability of the fly ash towards organics in water include temperature; solution pH; and interactions between solute molecules and fly ash, and between solvent molecules and fly ash. Thus, there is an essential need to characterize each coal fly ash type to enable potential correlation between coal fly ash structural properties and the effectiveness of the adsorption characteristics of coal fly ash for immobilizing organic hazardous waste compounds. The composition and properties of pulverized fly ash depend on the type of coal burned and the nature of the combustion process. Thus, fly ashes from different origins may have significantly different sorption properties towards organic compounds of environmental interest. Eastern and western coal fly ashes differ significantly in their physical and chemical properties. The major minerals found in coal fly ash are α-quartz (SiO2), mullite (3A12O3 ·2SiO2), hematite (Fe2O3), magnetite (Fe3O4), lime (CaO), and gypsum (CaSO4·2H2O). Little is known of the coordination state and distribution of siliceous and aluminous material in coal fly ashes. Most siliceous and aluminous materials in fly ash are amorphous and thus are not detected or quantified by X-ray techniques.

Characterization of North American Lignite Fly Ashes II. XRD Mineralogy

1987 ◽  
Vol 113 ◽  
Author(s):  
G. J. McCarthy ◽  
D. M. Johansen ◽  
A. Thedchanamoorthy ◽  
S. J. Steinwand ◽  
K. D. Swanson
Keyword(s):  
Fly Ash ◽  
Bituminous Coal ◽  
Coal Fly Ash ◽  
Fly Ashes ◽  
X Ray ◽  
Mining Areas ◽  
Lignite Fly Ash ◽  
Coal Fly Ashes ◽  
Ferrite Spinel

ABSTRACTX-ray powder diffraction has been used to determine the crystalline phase mineralogy in samples of fly ash from each of the lignite mining areas of North America. The characteristic phases of North Dakota lignite fly ashes were periclase, lime, merwinite and the sulfate phases anhydrite, thenardite and a sodalite-structure phase. Mullite was absent in these low-Al2O3 ashes. Montana lignite ash mineralogy had characteristics of ND lignite and MT subbituminous coal fly ashes; mullite and C3A were present and the alkali sulfates were absent. Texas and Louisiana lignite fly ashes had the characteristic mineralogy of bituminous coal fly ash: quartz, mullite, ferrite-spinel (magnetite) and minor hematite. Even though their analytical CaO contents were 7–14%, all but one lacked crystalline CaO-containing phases. Lignite fly ashes from Saskatchewan were generally the least crystalline of those studied and had a mineralogy consisting of quartz, mullite, ferrite spinel and periclase. Quantitative XRD data were obtained. The position of the diffuse scattering maximum in the x-ray diffractograms was indicative of the glass composition of the lignite fly ash.

scholarly journals DETERMINING THE ROLE OF INDIVIDUAL FLY ASH PARTICLES IN INFLUENCING THE VARIATION IN THE OVERALL PHYSICAL, MORPHOLOGICAL, AND CHEMICAL PROPERTIES OF FLY ASH

2016 ◽  
Vol 56 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Usman Haider ◽  
Zdenek Bittnar ◽  
Lubomír Kopecky ◽  
Vít Šmilauer ◽  
Jaroslav Pokorny ◽  
...  
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Chemical Properties ◽  
Cementitious Materials ◽  
Individual Particle ◽  
Particle Analysis ◽  
Fly Ashes ◽  
Alumino Silicate ◽  
Individual Particles

The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic,where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

Mechanical Properties of Mortars Prepared by Alkali Activated Fly Ash Coming from Different Production Batches

2015 ◽  
Vol 244 ◽  
pp. 140-145 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Materials ◽  
Chemical Properties ◽  
Raw Material ◽  
Fly Ashes ◽  
Coal Burning ◽  
Alkali Solutions ◽  
One Year ◽  
Alkali Activated

Fly ash is a well utilizable secondary raw material for the production of alkali activated construction materials. It is a significant alumina-silicates source suitable for the chemical reaction resulting in hardened composites. Physical and chemical properties of fly ashes as a co-product of coal burning mainly depend on characteristics of coal, burning temperature and combustion conditions. High variability of the properties of fly ash causes an uncertainty in the properties of alkali activated mortars. Time behaviour of the composition of the fly ash produced in a heating plant located in Košice, Slovakia as well as leaching behaviour of both alumina and silica from particular batches during one-year period was documented. Leaching tests were carried out using the distilled water and alkali solutions with three different concentrations. Both compressive and tensile strengths of alkali activated mortars were measured, and the correlation between the mechanical properties of hardened mortars and the chemical composition of fly ashes as well as their leaching characteristics was investigated.

Synthesis of Zeolite 13X from Coal Fly Ashes and Properties of the Zeolite Products

2014 ◽  
Vol 675-677 ◽  
pp. 724-727 ◽  
Author(s):  
Wei Wei Tu ◽  
Yong Feng Zhang ◽  
Jie Bai ◽  
Wei Liu
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Uv Spectrophotometry ◽  
Zeolite 13X ◽  
Alkali Fusion ◽  
Coal Fly Ashes ◽  
Homogeneous Composition ◽  
Better Than ◽  
Good Agreement

Synthesis of pure-form zeolite 13X was investigated using the alkali fusion-hydrothermal method to dissolve Si and Al sources from fly ash, and with the addition of Si source, to prepare initial gel. Experimental results demonstrated, the regular morphology and homogeneous composition are in good agreement with standard zeolite 13X by characterization of XRD, SEM and IR. The properties of adsorption and CEC values were evaluated by BET and UV-spectrophotometry, respectively. All properties are much better than commercial zeolite 13X. Our results further revealed that like coal fly ash after alkali fusion pretreatment can be used for zeolite synthesis. Thus, It demonstrates a promising feedstock for the green synthesis of zeolites directly without experiencing intermediate chemicals.

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