Measuring Graphitic Carbon and Crystalline Minerals in Coals and Bottom Ashes

1987 ◽  
Vol 31 ◽  
pp. 343-349 ◽  
Author(s):  
David L. Wertz ◽  
Leo W. Collins ◽  
Franz Froelicher
Keyword(s):  
Energy Source ◽  
Fly Ash ◽  
Chemical Species ◽  
Primary Energy ◽  
Toxic Chemical ◽  
Atom Pair ◽  
Crystalline Phases ◽  
X Ray ◽  
X Ray Scattering ◽  
Lignite Fly Ash

AbstractThe use of coal, as either a primary energy source or as a source of feedstock chemicals, has been complicated by the noxious and toxic chemical species formed in its gaseous effluents and also by the huge quantities of ash vhich result from its processing. Both the noxious gases and the ash have been the subjects of Federal legislations.X-ray powder patterns (XRPP), composed of atom-pair and self x~ray scattering and the diffraction produced by crystalline phases, have long been used to investigate coals and particularly their combustion ashes (1-3). Over twenty different crystalline phases have recently been reported to exist in certain lignite fly ash (3). Analysis of the crystalline phases has typically been emphasized in previous papers involving coals and ashes, but the amorphous scattering has been given little treatment.

scholarly journals Fingerprints of electronic, spin and structural dynamics from resonant inelastic soft X-ray scattering in transient photo-chemical species

2018 ◽  
Vol 20 (10) ◽  
pp. 7243-7253 ◽  
Author(s):  
Jesper Norell ◽  
Raphael M. Jay ◽  
Markus Hantschmann ◽  
Sebastian Eckert ◽  
Meiyuan Guo ◽  
...  
Keyword(s):  
Electronic State ◽  
Structural Dynamics ◽  
Chemical Species ◽  
Inversion Symmetry ◽  
Chemical Dynamics ◽  
Transient Species ◽  
X Ray ◽  
X Ray Scattering ◽  
Electronic Spin ◽  
Ray Scattering

Inversion-symmetry separation of electronic state manifolds in RIXS enables identification of transient species in photo-chemical dynamics.

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.

X-ray Diffraction Analysis of Fly Ash. II. Results

1990 ◽  
Vol 34 ◽  
pp. 387-394 ◽  
Author(s):  
G. J. McCarthy ◽  
J. K. Solem
Keyword(s):  
Fly Ash ◽  
Diffraction Analysis ◽  
Chemical Constituents ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Power Station ◽  
Crystalline Phases ◽  
X Ray ◽  
High Calcium

AbstractA protocol for semi-quantitative XRD analysis of fly ash has been applied to 178 ashes in studies of the typical mineralogy of high-calcium and iow-calcium fly ash, the consistency of fly ash mineralogy from a typical power station, the partitioning of chemical constituents into crystalline phases, and the crystalline phases relevant to the use of fly ash in concrete.

Ptychographic X-ray Microscopy with the Vacuum Imaging Apparatus HORST

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Thomas Gorniak ◽  
Axel Rosenhahn
Keyword(s):  
Chemical Species ◽  
X Rays ◽  
Central Importance ◽  
Coherent Imaging ◽  
X Ray ◽  
Spatial Sensitivity ◽  
Water Window ◽  
X Ray Scattering ◽  
Microscopic Studies ◽  
Key Drivers

AbstractImaging is one of the key drivers for new scientific insights – from the observation of distant stars in astronomy to microscopic studies of sub-cellular structures in biology. In the latter case, X-rays are a versatile probe due to their small wavelength and thus high spatial sensitivity. We give an overview of applicable lensless, coherent imaging approaches relying on scattering with a focus on ptychographic microscopy and discuss the experimental requirements for the soft X-ray scattering experiment HORST. Besides the experiment itself, we highlight the importance of sample environments, especially when biological specimens are investigated. Here, the water window is of central importance. In addition to exploitation of the contrast and resolution, resonant ptychography allows to distinguish chemical species at high spatial resolution with both phase and amplitude contrast.

Microscopic Structure Analysis in Disordered Materials using Anomalous X-ray Scattering

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Jens Rüdiger Stellhorn ◽  
Shinya Hosokawa ◽  
Wolf-Christian Pilgrim
Keyword(s):  
Materials Science ◽  
High Reliability ◽  
Structural Characteristics ◽  
Chemical Species ◽  
Model Systems ◽  
X Ray Diffraction ◽  
Basic Principles ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractAlthough X-ray diffraction is still mainly used to determine crystal structures, the demand for an understanding of the atomic arrangement in disordered matter has progressively become more important over the past decades. However, apart from simple model systems, it is still a challenging task to unravel the microscopic ordering of the atoms in amorphous multi-component materials, although this knowledge becomes increasingly important in modern materials science, in which the physical properties are often related to the microscopic ordering of the different chemical species of the substance. This article reports about the combination of Anomalous X-ray Scattering (AXS) with Reverse Monte Carlo Computer simulation (RMC) as a proper tool to precisely determine the microscopic structural characteristics in such systems with high reliability. The basic principles of the method will be illustrated and some examples of modern materials will be given to proof the applicability and the capability of this method.

The local post-perovskite structure and its temperature dependence: atom-pair distances in CaIrO3revealed through analysis of the total X-ray scattering at high temperatures

2008 ◽  
Vol 41 (4) ◽  
pp. 776-783 ◽  
Author(s):  
C. David Martin
Keyword(s):  
Distribution Function ◽  
Long Range ◽  
Perovskite Structure ◽  
Pair Distribution Function ◽  
Short Range ◽  
Structure Refinement ◽  
Atom Pair ◽  
X Ray ◽  
X Ray Scattering ◽  
Short Range Structure

The temperature-dependent post-perovskite structure model of MgSiO3is reinvestigated through analysis of the atom-pair distances observed experimentallyviaFourier transformation of X-ray diffraction and diffuse scattering, the total X-ray scattering, from CaIrO3. In contrast to the results of a previous Rietveld structure refinement, which shows a negative or null thermal expansion of Ir—O and Ca—O bond lengths within the average long-range structure, visual inspection of these atom-pair distances in the pair-distribution function, in addition to structure models fitted through least-squares refinement to this local-structure data, strongly suggests that these distances between atom pairs increase with temperature. The average long-range structure of CaIrO3, visible from Rietveld structure refinement, is distinct from the short-range structure (≤ 18 Å) at all of the temperatures examined in this study (325–1114 K) and is reproduced in structure models fitted to the pair-distribution function extending to sufficiently long atom-pair distances (≥ 50 Å). While previous data obtained with Rietveld structure refinement show the iridium coordination octahedra to distort with increasing temperature, models of the short-range structure demonstrate that these polyhedra instead reduce distortion and rotate in a manner similar to that occurring in the perovskite structure.

scholarly journals Evaluation of the Bioavailability and Translocation of Selected Mobile Chemical Species by Brassica juncea and Spinacea oleracea L for a South African Power Utility Coal Fly Ash

2018 ◽  
Author(s):  
Aluwani Shiridor Mashau ◽  
Mugera Wilson Gitari ◽  
Segun Ajayi Akinyemi
Keyword(s):  
Fly Ash ◽  
South African ◽  
Brassica Juncea ◽  
Coal Fly Ash ◽  
Chemical Species ◽  
Mineralogical Composition ◽  
Power Utility ◽  
Potential Health ◽  
X Ray ◽  
Spinacea Oleracea

This study evaluated the physicochemical, mineralogical properties, mobile chemical species’ bioavailability and translocation in Brassica juncea and Spinacea oleracea L plants of a South African coal fired power utility. Coal fly ash (CFA) disposal is associated with various environmental and health risks including air, soil, surface and ground water pollution due to the leaching of toxic chemical species; these ends up in food webs affecting  human health, while repeated inhalation causes bronchitis, silicosis, hair loss and lung cancer. The morphology, chemical, and mineralogical composition of CFA were determined using Scanning Electron Microscopy (SEM), X-ray fluorescence (XRF) and X-ray Diffraction, respectively. In pot culture experiments, S. oleracea L and B. juncea plants were grown in three sets of pots containing CFA (set 1), soil (set 2) and a mixture of CFA plus soil at ratio 1:1 (50% CFA: 50% soil) (set 3), while no plants were grown in set 4 as a control for the leachate samples. SEM showed that surface morphology of CFA has a lower degree of sphericity with irregular agglomerations of many particles. The XRF results revealed that CFA contains 43.65%, 22.68% and 10.89% of SiO2, Al2O3 and Fe2O3 respectively which indicate that the CFA is an alumino-silicate material. While XRD showed that the coal CFA contains mullite as a major phase followed by quartz mineral phases. Chemical species such as Fe, Mn, B, Ba and Zn were accumulated highly in most parts of the plant species. However, B. juncea showed higher potential to accumulate chemical species as compared to S. oleracea L. The bioconcentration and translocation factors (BF and TF) showed that B. juncea was the most effective in terms of bioconcentration and translocation of most of the chemical species. This indicates that B. juncea has potential in application for phytoremediation of CFA dumps and could contribute to remediation of CFA dumps and reduction of potential health and environmental impacts associated with CFA.

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