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Patrick Landais - One of the best experts on this subject based on the ideXlab platform.
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statistical determination of geochemical parameters of Coal and kerogen Macerals from transmission micro infrared spectroscopy data
Organic Geochemistry, 1995Co-Authors: Patrick LandaisAbstract:Abstract A set of samples including type I and type II kerogens and Coals (type III), as well as two series of artificially oxidized and matured Coals were analyzed by Fourier transform infrared spectroscopy (FTIR). Major infrared bands (aliphatic and aromatic CH, CO and CC) were integrated in order to draw correlations with geochemical parameters obtained on bulk powdered samples: Rock-Eval HI, H C , O H and O C atomic ratios. Coal Macerals (bituminite, resinite, vitrinite), megaspores and torbanite components (algal bodies and matrix) were characterized by in situ micro-infrared spectroscopy. The correlations derived from FTIR analysis of bulk samples were used to deduce the geochemical parameters of Coal and kerogen Macerals from their micro-infrared characteristics. Results indicate that H C atomic ratios and Rock-Eval Hydrogen Indices exhibit good correlations (0.9 FA′ = 2860 cm −1 (2860 cm −1 + 1600 cm −1 ) and CHali infrared parameters that allow the HI and H C of single Macerals to be calculated. However a significant scattering of the data points around the regression line is observed when using large sets of samples. Correlations were recalculated on a limited series of oxidized Coals in order to improve their quality. The derived equations facilitate the determination of the evolution of HI as well as H C and O C atomic ratios of different Coal Macerals during artificial oxidation. Results are compared to the recomputed data on Coal, deduced from both the micro-infrared analysis of Macerals and the maceral composition of Coal.
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In situ examination of Coal Macerals oxidation by micro-FT-i.r. spectroscopy
Fuel, 1993Co-Authors: Patrick Landais, Aïcha RochdiAbstract:Abstract Two heterogeneous Coals, from the Mahakam delta (HY 158) and the Campine basin (SP 1), have been selected for an in situ study of individual maceral oxidation. HY 158 is vintrinite rich (80%) but also contains resinite and bituminite, while SP 1 is a cannel Coal composed of spores, vitrinite and inertinite. Doubly-polished thin-sections have been prepared and photographed in order to select the appropriate individual maceral areas. The thin-sections were oxidized at 140 °C in a ventilated oven for 1 to 384 h. Between each oxidation step the selected areas were analysed by Fourier transform micro-infrared spectroscopy (micro-FT-i.r.). Aliphatic CH consumption, carbonyl, carboxyl and ether content increases are observed. However, results indicate that Macerals behave differently when submitted to increasing oxidation: 1. (1) extents and rates of oxidative alteration strongly depend on the nature of the maceral; 2. (2) two different vitrinites can exhibit contrasting behaviour; 3. (3) slight differences in the chemical composition of the unoxidized Macerals can induce significant chemical variations during the oxidation process. Comparison with global FT-i.r. data obtained on powdered and oxidized parent Coal has been carried out (HY 158) and although there are similarities, variation in the extent of the oxidative alteration occurs.
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transmission micro infrared spectroscopy an efficient tool for microscale characterization of Coal
Fuel, 1991Co-Authors: Aïcha Rochdi, Patrick LandaisAbstract:Abstract Fourier transform infrared (FT-i.r.) micro-scale analysis of organic matter can be applied to evaluate the heterogeneity and to characterize the individual petrographic components of Coal. Suitable sample preparation development was required to benefit from the potential advantages of this technique. Sections of Coal (10–20 μm thick) have been prepared by slightly modifying the polished thin section preparation or by using a wire saw. Ultramicrotome sections (0.5–1.5 μm thick) were also designed. The micro-FT-i.r. spectra display good signal to noise ratio and a good individualization of bands. Advantages of the microspectroscopic technique over the KBr pellet global mode are: better spectral quality; the absence of adsorbed water; and better quantitative results. The limitations of the method are also discussed with special emphasis on the effect of Coal mineral content. Applications of micro-FT-i.r. to characterize Coal Macerals and alteration phenomena are presented.
Maria Mastalerz - One of the best experts on this subject based on the ideXlab platform.
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Coal Macerals chemistry and its implications for selectivity in Coal floatability
International Journal of Coal Preparation and Utilization, 2015Co-Authors: Maria Holuszko, Maria MastalerzAbstract:Macerals are the smallest components of Coal recognizable on the microscopic scale and, even when optically homogeneous, they may have variable elemental and molecular chemistry not only across different Coal ranks but also in iso-rank Coals. These variations in maceral chemistry may have significant impact on the behavior of the Coal during processing and may also complicate predictions of this behavior. Flotation is one of the processes that is impacted by intermaceral variations. Flotation is used as a main process to upgrade the fines of higher rank Coals. It depends on the surface properties of Coal particles, hence their chemical composition. Most of the minerals associated with Coal, with the exception of a few (elemental sulfur or some pyrites), are hydrophilic and can easily be separated if liberated from Coal by flotation. The organic matter (Macerals) possesses different degrees of hydrophobicity, and its response to flotation can vary depending on the surface properties that result from chemic...
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The investigation of chemical structure of Coal Macerals via transmitted-light FT-IR microscopy by X. sun
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: James C. Hower, Maria Mastalerz, Isabel Suárez-ruiz, Alan C. CookAbstract:A recent paper by Sun [X. Sun, Spectrochim. Acta A 62 (1-3) (2005) 557] attempts to characterize a variety of liptinite, termed "barkinite", from Chinese Permian Coals. The component identified does not appear to fundamentally differ from previously-described liptinite Macerals included in the International Committee for Coal and Organic Petrology's system of maceral nomenclature. Further, chemical comparisons made with Macerals from Coals of different rank and age are flawed because the author did not account for changes in chemistry with rank or for the chemical changes associated with botanical changes through geologic time. The author has not satisfactorily proved his hypothesis that the component differs morphologically or chemically from known liptinite-group Macerals.
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determination of nitrogen in Coal Macerals using electron microprobe technique experimental procedure
International Journal of Coal Geology, 2001Co-Authors: Maria Mastalerz, Lila W. GurbaAbstract:This paper discusses nitrogen determination with the Cameca SX50 electron microprobe using PC0 as an analyzing crystal. A set of conditions using differing accelerating voltages, beam currents, beam sizes, and counting times were tested to determine parameters that would give the most reliable nitrogen determination. The results suggest that, for the instrumentation used, 10 kV, current 20 nA, and a counting time of 20 s provides the most reliable nitrogen determination, with a much lower detection limit than the typical concentration of this element in Coal. The study demonstrates that the electron microprobe technique can be used to determine the nitrogen content of Coal Macerals successfully and accurately.
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application of reflectance micro fourier transform infrared spectrometry in studying Coal Macerals comparison with other fourier transform infrared techniques
Fuel, 1995Co-Authors: Maria MastalerzAbstract:Abstract The applicability of the reflectance micro-Fourier transform infrared (FT-i.r.) technique to analyse the distribution of functional groups in Coal is discussed. The spectra of a series of Coals from lignite to anthracite obtained using reflectance micro-FT-i.r. were compared with those of the same materials but obtained using transmission micro-FT-i.r. and KBr pellet techniques. This comparison shows that (1) band absorbances in the transmission mode are much higher than those in the reflectance mode; (2) band peak positions are the same in the transmission and reflectance modes as long as Kramers-Kroning transformation is applied; and (3) the 700–900 cm−1 aromatic-dominated region has higher absorbance in the reflectance than transmission mode. Reflectance spectra and KBr pellet technique spectra compare very closely; band absorbances and band locations are the same or almost the same. The main difference between reflectance micro-FT-i.r. and KBr pellet techniques is a much higher absorbance in the 700–900 cm−1 region in the reflectance mode. The results indicate that reflectance spectra can be utilized to characterize functional groups in organic matter under most conditions. The ease of sample preparation, the potential to analyse large intact samples and the ability to characterize areas as small as 30 μm are the main advantages of reflectance micro-FT-i.r.. The quantitative aspects of reflectance micro-FT-i.r. require further study.
Colin R. Ward - One of the best experts on this subject based on the ideXlab platform.
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application of attenuated total reflectance micro fourier transform infrared atr ftir spectroscopy to the study of Coal Macerals examples from the bowen basin australia
International Journal of Coal Geology, 2007Co-Authors: Zhongsheng Li, Peter M Fredericks, Llewellyn Rintoul, Colin R. WardAbstract:Attenuated total reflectance micro-Fourier transform infrared (ATR-FTIR) spectrometry has been successfully used to characterise Coal Macerals, in particular telocollinite, and to investigate changes in the aromatic and aliphatic functional groups in the telocollinite, over a wide rank range (Rvmax from 0.39 to 3.52%) in Coals from the Bowen Basin, Queensland, Australia. The results show that ATR-FTIR is very sensitive to the increasing aromaticity (the fraction of carbon atoms involved in aromatic units) of the telocollinites, and thus is a very useful tool to study the evolution of aromatic and aliphatic functional groups with maturation of telocollinite, and also to differentiate and characterise the various Macerals in Coal samples. In comparison with other micro-FTIR techniques, ATR-FTIR has many advantages: (1) no difficult and time-consuming procedures are required to obtain “pure” maceral separations, or for preparation of thin Coal slices; (2) the ATR-FTIR spectra have better signal-to-noise ratio and increased sensitivity; (3) the ATR-FTIR spectra are similar to absorption spectra, but without significant spectral distortion.
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Occurrence of non-mineral inorganic elements in low-rank Coal Macerals as shown by electron microprobe element mapping techniques
International Journal of Coal Geology, 2006Co-Authors: Colin R. Ward, Lila W. GurbaAbstract:Significant proportions of inorganic elements (up to 1.5% Ca, up to 0.5% Al and up to 0.7% Fe) are consistently found in electron microprobe studies of such otherwise ‘clean’ Coal Macerals, especially vitrinite Macerals, without any visible minerals or mineral inclusions in the Macerals concerned. Detailed mapping of the concentration of these elements in visibly ‘clean’ Macerals of several low-rank Coals reveals that a majority of inorganic elements (Al, Ca and Fe) occur as non-mineral entities rather than discrete mineral particles, and are intimately distributed throughout the Macerals; the distribution of the these elements is very similar to that of organic S, particularly in the collotelinite and fusinite of the same Coal samples. The baseline concentrations seen in the inorganic element maps (Al, Ca, Fe and S) normally agree with the averaged concentrations derived from more general microprobe analysis of the same Macerals in the Coals, indicating that the elemental mapping technique provides a consistent basis and a powerful tool for evaluating the modes of inorganic element occurrence in Coal Macerals. The overall consistency in the baseline levels, instead of spike-like peaks expected from micron-sized mineral inclusions, suggests that these elements occur as an inherent part of the organic structure in the Macerals concerned, possibly as a combination of exchangeable ions, carboxylates, chelates and other organometallic compounds; they may also be held by physical absorption and adsorption mechanisms. Better understanding the mode of occurrence of these non-mineral inorganic elements may provide important insights into a number of Coal utilisation processes, such as catalyst reactions, slagging and fouling, and emission generation associated with combustion and carbonisation operations.
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elemental composition of Coal Macerals in relation to vitrinite reflectance gunnedah basin australia as determined by electron microprobe analysis
International Journal of Coal Geology, 2000Co-Authors: Lila W. Gurba, Colin R. WardAbstract:Abstract The elemental composition of Macerals in high-volatile bituminous Coals from the Gunnedah Basin, New South Wales, Australia, has been analysed by light-element electron microprobe techniques. The results have been evaluated in relation to maximum vitrinite reflectance trends in vertical section, including the effects of marine influence and igneous intrusions on the Coal-bearing sequence. Mean maximum vitrinite (telocollinite and desmocollinite) reflectance for the analysed samples ranges from 0.63% to 0.99%, and to 2.2% for Coal affected by igneous intrusions. The carbon content of the vitrinite, as determined by electron microprobe, ranges from 79.74% to 86.07%, and up to 89.06% for the heat-affected Coal studied. A simple relationship cannot be established between the reflectance of the vitrinite and its carbon content over this range of Coal samples. Vitrinite in marine influenced Coals (with suppressed reflectance) appears to have a slightly higher carbon content than vitrinite in isorank Coals without marine influence. The increase in carbon may be due to incorporation of carbon and sulphur–rich lipoid material into the vitrinite component. Notwithstanding these differences, the carbon content of vitrinite (telocollinite) seems to be affected only slightly by the depositional changes that cause suppression of vitrinite reflectance in marine-influenced Coals. Telocollinite carbon content may therefore be a useful alternative to vitrinite reflectance as a rank indicator in maturation studies. The carbon content of whole-Coal samples, determined by ultimate analysis, shows in vertical section a trend intermediate between the carbon of the vitrinite determined by electron microprobe and that of the associated inertinite Macerals. Whole-Coal analysis data in this range depend on the relative proportions of the different Macerals present, as well as the rank of the Coal concerned. Coals affected by igneous intrusion show a different relationship between carbon and oxygen of vitrinite (telocollinite), relative to Coals where the rank is determined by depth of burial alone. The difference in C–O relationships suggests that the short-term heating associated with intrusions produces chemical changes in Macerals that are not paralleled in more normal rank advance.
James C. Hower - One of the best experts on this subject based on the ideXlab platform.
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an investigation of wulantuga Coal cretaceous inner mongolia Macerals paleopathology of faunal and fungal invasions into wood and the recognizable clues for their activity
International Journal of Coal Geology, 2013Co-Authors: James C. Hower, Jennifer M K Okeefe, Nicola J Wagner, Shifeng Dai, Xibo Wang, Weifeng XueAbstract:Coal Macerals are the product of a complex series of decompositional and preservational pathways from living woody and herbaceous tissues to the variety of forms seen in Coal. The Cretaceous Wulantuga Coal (Inner Mongolia, China) offers an opportunity to observe a number of maceral forms resulting from these disparate pathways. Assemblages of coprolites within fusinite strongly suggest an origin related to arthropod ingestion and consequent in situ emplacement of the macrinitic coprolites within the damaged wood structure, followed by combustion of the whole to achieve the observed reflectance.
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notes on the origin of inertinite Macerals in Coal evidence for fungal and arthropod transformations of degraded Macerals
International Journal of Coal Geology, 2011Co-Authors: James C. Hower, Cortland F. Eble, Allison R. Richardson, Jennifer M K Okeefe, Anne Raymond, Bruno Valentim, Thomas J Volk, Anne B Satterwhite, Rachel Hatch, J.d. StuckerAbstract:The role of fungus in the formation of Coal Macerals, both as a primary contributor in the form of a fungus fossil/maceral funginite, and in their role in degrading wood, thus producing degraded maceral forms, has been established. Fungus, in the course of breaking down the lignin and cellulose in wood, make the wood more digestible for grazers, such as arthropods. In turn, the remnants of the digested wood and anything else eaten but not completely digested are excreted and can be preserved intact; eaten by other fauna with a repeat of the cycle; or colonized by bacteria and/or coprophilous fungi with or without subsequent preservation. Ultimately, the coprolites can be preserved as a form of macrinite.
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The investigation of chemical structure of Coal Macerals via transmitted-light FT-IR microscopy by X. sun
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: James C. Hower, Maria Mastalerz, Isabel Suárez-ruiz, Alan C. CookAbstract:A recent paper by Sun [X. Sun, Spectrochim. Acta A 62 (1-3) (2005) 557] attempts to characterize a variety of liptinite, termed "barkinite", from Chinese Permian Coals. The component identified does not appear to fundamentally differ from previously-described liptinite Macerals included in the International Committee for Coal and Organic Petrology's system of maceral nomenclature. Further, chemical comparisons made with Macerals from Coals of different rank and age are flawed because the author did not account for changes in chemistry with rank or for the chemical changes associated with botanical changes through geologic time. The author has not satisfactorily proved his hypothesis that the component differs morphologically or chemically from known liptinite-group Macerals.
Lila W. Gurba - One of the best experts on this subject based on the ideXlab platform.
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Occurrence of non-mineral inorganic elements in low-rank Coal Macerals as shown by electron microprobe element mapping techniques
International Journal of Coal Geology, 2006Co-Authors: Colin R. Ward, Lila W. GurbaAbstract:Significant proportions of inorganic elements (up to 1.5% Ca, up to 0.5% Al and up to 0.7% Fe) are consistently found in electron microprobe studies of such otherwise ‘clean’ Coal Macerals, especially vitrinite Macerals, without any visible minerals or mineral inclusions in the Macerals concerned. Detailed mapping of the concentration of these elements in visibly ‘clean’ Macerals of several low-rank Coals reveals that a majority of inorganic elements (Al, Ca and Fe) occur as non-mineral entities rather than discrete mineral particles, and are intimately distributed throughout the Macerals; the distribution of the these elements is very similar to that of organic S, particularly in the collotelinite and fusinite of the same Coal samples. The baseline concentrations seen in the inorganic element maps (Al, Ca, Fe and S) normally agree with the averaged concentrations derived from more general microprobe analysis of the same Macerals in the Coals, indicating that the elemental mapping technique provides a consistent basis and a powerful tool for evaluating the modes of inorganic element occurrence in Coal Macerals. The overall consistency in the baseline levels, instead of spike-like peaks expected from micron-sized mineral inclusions, suggests that these elements occur as an inherent part of the organic structure in the Macerals concerned, possibly as a combination of exchangeable ions, carboxylates, chelates and other organometallic compounds; they may also be held by physical absorption and adsorption mechanisms. Better understanding the mode of occurrence of these non-mineral inorganic elements may provide important insights into a number of Coal utilisation processes, such as catalyst reactions, slagging and fouling, and emission generation associated with combustion and carbonisation operations.
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determination of nitrogen in Coal Macerals using electron microprobe technique experimental procedure
International Journal of Coal Geology, 2001Co-Authors: Maria Mastalerz, Lila W. GurbaAbstract:This paper discusses nitrogen determination with the Cameca SX50 electron microprobe using PC0 as an analyzing crystal. A set of conditions using differing accelerating voltages, beam currents, beam sizes, and counting times were tested to determine parameters that would give the most reliable nitrogen determination. The results suggest that, for the instrumentation used, 10 kV, current 20 nA, and a counting time of 20 s provides the most reliable nitrogen determination, with a much lower detection limit than the typical concentration of this element in Coal. The study demonstrates that the electron microprobe technique can be used to determine the nitrogen content of Coal Macerals successfully and accurately.
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elemental composition of Coal Macerals in relation to vitrinite reflectance gunnedah basin australia as determined by electron microprobe analysis
International Journal of Coal Geology, 2000Co-Authors: Lila W. Gurba, Colin R. WardAbstract:Abstract The elemental composition of Macerals in high-volatile bituminous Coals from the Gunnedah Basin, New South Wales, Australia, has been analysed by light-element electron microprobe techniques. The results have been evaluated in relation to maximum vitrinite reflectance trends in vertical section, including the effects of marine influence and igneous intrusions on the Coal-bearing sequence. Mean maximum vitrinite (telocollinite and desmocollinite) reflectance for the analysed samples ranges from 0.63% to 0.99%, and to 2.2% for Coal affected by igneous intrusions. The carbon content of the vitrinite, as determined by electron microprobe, ranges from 79.74% to 86.07%, and up to 89.06% for the heat-affected Coal studied. A simple relationship cannot be established between the reflectance of the vitrinite and its carbon content over this range of Coal samples. Vitrinite in marine influenced Coals (with suppressed reflectance) appears to have a slightly higher carbon content than vitrinite in isorank Coals without marine influence. The increase in carbon may be due to incorporation of carbon and sulphur–rich lipoid material into the vitrinite component. Notwithstanding these differences, the carbon content of vitrinite (telocollinite) seems to be affected only slightly by the depositional changes that cause suppression of vitrinite reflectance in marine-influenced Coals. Telocollinite carbon content may therefore be a useful alternative to vitrinite reflectance as a rank indicator in maturation studies. The carbon content of whole-Coal samples, determined by ultimate analysis, shows in vertical section a trend intermediate between the carbon of the vitrinite determined by electron microprobe and that of the associated inertinite Macerals. Whole-Coal analysis data in this range depend on the relative proportions of the different Macerals present, as well as the rank of the Coal concerned. Coals affected by igneous intrusion show a different relationship between carbon and oxygen of vitrinite (telocollinite), relative to Coals where the rank is determined by depth of burial alone. The difference in C–O relationships suggests that the short-term heating associated with intrusions produces chemical changes in Macerals that are not paralleled in more normal rank advance.