Geochemical and petrographic analysis of graphitized coals from Central Hunan, China

Li, Kuo; Rimmer, Susan M.; Liu, Qinfu

doi:10.1016/j.coal.2018.06.009

Cited by 63 publications

(66 citation statements)

References 61 publications

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“…These data displacement can be attributed to the differences between Rmax and R MAX RIS in deformed tectonic terrains (Kilby 1988; Duber et al 2000). Given that Li et al (2019) studied samples from the coal beds in the Hunan central province, which are highly deformed (Li et al 2018), a biaxial RIS is expected. Only coal block sections oriented parallel to the b axis provide true R MAX values (Kilby 1988; Kwiecinska et al 2010).…”

Section: Resultsmentioning

confidence: 99%

“…Only coal block sections oriented parallel to the b axis provide true R MAX values (Kilby 1988; Kwiecinska et al 2010). Considering that, in previous work, Li et al (2018) had analyzed crushed coal samples embedded in resin, they probably measured an apparent maximum reflectance. Therefore, we removed these data from the regression data sets.…”

Section: Resultsmentioning

confidence: 99%

“…To further investigate G‐band width as a parameter to estimate structural organization of CM in this rank, G‐band width was plotted in Fig. 2 against the basal interlayer spacing of graphite (d 002 ), as obtained from XRD (Kwiecinska et al 2010; Rantitsch et al 2016a; Nakamura et al 2017; Li et al 2018, 2019). The obtained linear relationship is expressed in Equation (Table in supporting information).

d_{002 c a l c} (x) = a x + b

where x = G FWHM ; a = 0.00021 cm; b = 0.332; R 2 = 0.79; d 002 [0.335–0.349 nm]; G FWHM [15–69 cm ‐1 ]; n = 75.…”

Section: Resultsmentioning

confidence: 99%

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Evaluation of terrestrial carbonaceous matter aromatization by Raman spectroscopy and its application to C chondrites

Schmidt

Hinrichs

2020

Meteorit & Planetary Scien

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A Raman method to estimate the aromatization degree of carbonaceous matter (CM) was established, and calibrated by literature data respecting differences in acquisition procedures. The generated equations allowed a comparison of the G-band width to vitrinite reflectance, and to additional structural organization parameter extracted from X-ray powder diffraction. The relations between aromatization degree and peak temperatures from literature were then propagated to G-band width parameter. The applicability of these geothermometers is demonstrated by the consistency of data obtained for carbonaceous chondrites with previous estimations. Since the CM aromatization is controlled by peak temperature and time span, it is possible to estimate the duration of chondrite's heating events. The G-band width relation to elemental ratio trends of organic matter in chondrites, interplanetary dust particles, glucose, and saccharose-based semi-coke favors synthesis by formose route. These findings provide new approaches for the future development of chemical kinetic models for organic matter of chondrites. A reliable chemical model may allow the external calibration of numerical models for accurately evaluating the peak temperatures and cooling durations of chondrites.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

d_{002 c a l c} (x) = a x + b

where x = G FWHM ; a = 0.00021 cm; b = 0.332; R 2 = 0.79; d 002 [0.335–0.349 nm]; G FWHM [15–69 cm ‐1 ]; n = 75.…”

Section: Resultsmentioning

confidence: 99%

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Evaluation of terrestrial carbonaceous matter aromatization by Raman spectroscopy and its application to C chondrites

Schmidt

Hinrichs

2020

Meteorit & Planetary Scien

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“…CBG is the end-member product of the continuous evolution of coal [8][9][10]. With increasing metamorphic degrees, anthracite, semi-graphite, and graphite are progressively formed [11][12][13][14][15]. In recent years, optical analysis, X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) have been applied to characterize coal and CBG [11,[16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Strain-Induced Graphitization Mechanism of Coal-Based Graphite from Lutang, Hunan Province, China

et al. 2019

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Anthracite and coal-based graphite (CBG) samples were collected at varying distances from a granite intrusion. Optical microscopy, X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the structural evolution of CBG at different scales. The results indicated differences in the graphitization rates of coal macerals and crystallization degree of different graphite-like particles. Differentiated graphitization of coal was caused by deformation, which led to the discontinuous distribution of CBG. This indicates that samples located at the same distance from the intrusion were graphitized to different degrees or that CBG with a similar graphitization degree occurred at varying distances from the intrusion. A possible mechanism for graphitization is strain-induced graphitization, where the local stress concentration leads to preferred orientations of the basic structure units (BSUs), as well as the motion and rearrangement of structural defects, resulting in the formation of a locally ordered structure. The graphitization degree is enhanced as the local graphite structure spreads.

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“…The microcrystalline structures of FA and FC were studied by XRD (Figure a). The XRD curves of FA and FC show the obvious peak 002 with a 2θ range of 20°–30°, as well as the unobvious peak 100 with a 2θ range of 42°–48° . The comparison of the XRD spectra of FA and FC samples illustrates a significant change in the position and intensity of the broad band 002.…”

Section: Resultsmentioning

confidence: 92%

A study on the chemical state of carbon present in fine ash from gasification

Zhang

Gao

et al. 2019

Asia-Pacific J Chem Eng

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Taking feed coal as a reference, the chemical states, content changes, microstructure, distribution, and graphitizable extent of carbon present in gasification fine ash were investigated in detail. The results show that the fine ash includes a significant amount of unreacted carbon. The C1s spectrum is composed of four components in which the contents of C-C and C-H decrease dramatically and graphitized carbon (39.1%) presents. The elemental carbon primarily distributes on the layer structure, whereas elemental silicon and aluminum are mainly found on spherical particles embedded in the layer structure. After gasification, carbon atoms in gasification fine ash are arranged in an orderly manner, and the extent of graphitization of carbon increases, which indicates that carbon in feed coal may be partly graphitized and deposited in fine ash during gasification process.

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Geochemical and petrographic analysis of graphitized coals from Central Hunan, China

Cited by 63 publications

References 61 publications

Evaluation of terrestrial carbonaceous matter aromatization by Raman spectroscopy and its application to C chondrites

Evaluation of terrestrial carbonaceous matter aromatization by Raman spectroscopy and its application to C chondrites

Strain-Induced Graphitization Mechanism of Coal-Based Graphite from Lutang, Hunan Province, China

A study on the chemical state of carbon present in fine ash from gasification

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