The evolution of coal, examining the transitions from anthracite to natural graphite: a spectroscopy and optical microscopy evaluation

doi:10.1007/s11707-021-0967-4

Front. Earth Sci.

2023, Vol. 17

Issue (1) : 87-99 https://doi.org/10.1007/s11707-021-0967-4

RESEARCH ARTICLE

The evolution of coal, examining the transitions from anthracite to natural graphite: a spectroscopy and optical microscopy evaluation

Liang YUAN¹, Qinfu LIU¹(

), Kuo LI¹, Ying QUAN¹, Xiaoguang LI², Jonathan P. MATHEWS³

¹. School of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
². State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
³. The EMS Energy Institute, and the Leone Family Department of Energy and Mineral Engineering, Pennsylvania State University, University Park PA 16802, USA

Download: PDF(6954 KB) HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks

Abstract

Coal-derived natural graphite (CDNG) has multiple industrial applications. Here, ten metamorphic coals from anthracite to CDNG were obtained from Lutang and Xinhua in the Hunan Province and Panshi in the Jilin Province. Bulk characterization (proximate and ultimate analyses, X-Ray powder diffraction (XRD), and powder Raman spectroscopy), along with optical microscopy, scanning electron microscope (SEM) and micro-Raman spectroscopy were utilized to examine the transitions from anthracite to semi-graphite to CDNG. The XRD and Raman spectroscopy data indicate that from anthracite to highly ordered graphite the average crystal diameter (L_a) and height (L_c) increased from 6.1 and 4.6 nm to 34.8 and 27.5 nm, respectively. The crystalline parameters of the CDNG samples from Panshi and Lutang varied slightly when closer to the intrusive body. Optical microscopy and SEM indicated that in the anthracite samples there were thermoplastic vitrinite, devolatilized vitrinite, and some “normal” macerals. In the meta-anthracite, pyrolytic carbon, mosaic structure, and crystalline tar were present. In the CDNG there were flake graphite, crystalline aggregates, and matrix graphite. The crystalline aggregates show the highest structural ordering degree as determined from Raman spectral parameters (full-width at half maxima (G-FWHM) ~20 cm⁻¹, D1/(D1 + D2 + G) area ratio (R2) value < 0.5). The flake graphite is less ordered with G-FWHM ~28 cm ⁻¹ and 0.5 < R2 < 1, but a larger grain size (up to 50 μm). The mosaic structures were likely the precursors of the matrix graphite through in situ solid-state transformation. The pyrolytic carbon and crystalline tars are the transient phase of gas-state and liquid-state transformations. This study is beneficial to realize the rational utilization of CDNG.

Keywords micro-Raman spectroscopy structural ordering evolution coal-derived natural graphite XRD anthracite

Corresponding Author(s): Qinfu LIU

About author:

^* These authors contributed equally to this work.

Online First Date: 30 June 2022 Issue Date: 03 July 2023

Cite this article:

Liang YUAN,Qinfu LIU,Kuo LI, et al. The evolution of coal, examining the transitions from anthracite to natural graphite: a spectroscopy and optical microscopy evaluation[J]. Front. Earth Sci., 2023, 17(1): 87-99.

URL:

https://academic.hep.com.cn/fesci/EN/10.1007/s11707-021-0967-4
https://academic.hep.com.cn/fesci/EN/Y2023/V17/I1/87

Fig.1 Geological sketch map of the study region showing sampling locations (the Xinhua area was modified after (Li et al., 2018) and the Lutang area was modified after (Wang et al., 2019a)). (a) Panshi, Jilin Province, (b) Lutang, Hunan Province, and (c) Xinhua, Hunan Province.

Fig.2 Illustration of how to calculate asymmetry index (AI).

Tab.1 Proximate and ultimate analyses (part of data from Yuan et al. (2021) and Li et al. (2018))

Fig.3 Raw XRD and Raman spectra of demineralized coal and CDNG samples.

Tab.2 Crystalline parameter and basic properties of coal and CDNG

Fig.4 Relationship between AI (a), R2, and d₀₀₂ (b).

Fig.5 Representative photomicrographs and SEM images of samples. For optical observation, the images were taken under polarized light, × 50 anti-reflective objective, under oil immersion. (a) thermoplastic vitrinite (TV); (b) TV with 90° rotation; (c) devolatilized vitrinite (D-V); (d) desmocollinite (Dt); (e) edge side of the graphite sheet under SEM and (f) frontage of the graphite sheet under SEM.

Fig.6 Representative photomicrographs and SEM of samples. For optical observation, the images were taken under polarized light, × 50 anti-reflective objective, under oil immersion. (a) Pyrolytic carbon (PyC); (b) crystalline tar (CT) and mosaic structure (MS); (c) CT in the cell cavity; (d) CT in the fracture; (e) PyC under SEM; (f) a focus on the PyC microspheres of (e); (g) CT under SEM; (h) a focus on the CT of (g).

Fig.7 Representative photomicrographs and SEM of samples. For optical observation, the images were taken under polarized light, × 50 anti-reflective objective, under oil immersion. (a) PyC and Matrix graphite (MG) in semi-graphite; (b) flake graphite (FG) and MG in semi-graphite; (c) PyC, CT, and MG in semi-graphite; (d) MG, CT, and crystalline aggregates (CA) in CDNG; (e) and (f) FG and CA in CDNG. (g) MG under SEM in CDNG; (h) graphite basal plane (GBP); (i) and (j) graphite edge plane (GEP) under SEM in CDNG.

Fig.8 Representative micro-Raman patterns and peak-fitting patterns of the first-order region of the maceral/MDCs. (a) “Normal” vitrinite; (b) TV; (c) D-V; (d) CT in vacuoles; (e) MS; (f) MG; (g) FG and (h) CA. The X-axis is Raman shift (cm^?1) and the Y-axis is intensity (a.u).

Tab.3 Detailed micro-Raman parameters of selected samples

Fig.9 Crystalline aggregates and CTs within the same MDC particle and their micro-Raman pattern.

Fig.10 A plot of D1-FWHM versus R1 (Rouzaud et al., 2015).

1	D Y, Bai J Z, Huang Y R, Liu G Y, Wu X H, Wang (2005). Framework of mesozoic tectonic evolution in southeastern Hunan and the Hunan-Guangdong-Jiangxi border area. Chin Geol, 32(4): 566−570
2	O, Beyssac D Rumble (2014). Graphitic carbon: a ubiquitous, diverse, and useful geomaterial.Elements, 10(6): 415–420 https://doi.org/10.2113/gselements.10.6.415
3	C C, Blanche J N, Rouzaud D Dumas (1995). New data on anthracite graphitizibility
4	M, Bonijoly M, Oberlin A Oberlin (1982). A possible mechanism for natural graphite formation.Int J Coal Geol, 1(4): 283–312 https://doi.org/10.1016/0166-5162(82)90018-0
5	P R, Buseck O Beyssac (2014). From organic matter to graphite: Graphitization.Elements, 10(6): 421–426 https://doi.org/10.2113/gselements.10.6.421
6	P R, Buseck B J Huang (1985). Conversion of carbonaceous material to graphite during metamorphism.Geochim Cosmochim Acta, 49(10): 2003–2016 https://doi.org/10.1016/0016-7037(85)90059-6
7	R M, Bustin J V, Ross J N Rouzaud (1995). Mechanisms of graphite formation from kerogen: experimental evidence.Int J Coal Geol, 28(1): 1–36 https://doi.org/10.1016/0166-5162(95)00002-U
8	L I, Chao D H, Wang L M, Zhou H, Zhao X W, Li W J Qu (2017). Study on the Re-Os isotope composition of graphite from the Lutang graphite deposit in Hunan Province. Rock and Mineral Analysis
9	S, Duber J N, Rouzaud C, Bény D Dumas (1993). Graphitization of anthracites
10	A, Eckmann A, Felten A, Mishchenko L, Britnell R, Krupke K S, Novoselov C Casiraghi (2012). Probing the nature of defects in graphene by Raman spectroscopy.Nano Lett, 12(8): 3925–3930 https://doi.org/10.1021/nl300901a pmid: 22764888
11	D, González M A, Montes-Morán A B Garcia (2003). Graphite materials prepared from an anthracite: a structural characterization.Energy Fuels, 17(5): 1324–1329 https://doi.org/10.1021/ef0300491
12	F, Goodarzi O R, Eckstrand L, Snowdon B, Williamson L D Stasiuk (1992). Thermal metamorphism of bitumen in archean rocks by ultramafic volcanic flows.Int J Coal Geol, 20(1): 165–178 https://doi.org/10.1016/0166-5162(92)90009-L
13	A, Guedes B, Valentim A C, Prieto F Noronha (2012). Raman spectroscopy of coal macerals and fluidized bed char morphotypes.Fuel, 97: 443–449 https://doi.org/10.1016/j.fuel.2012.02.054
14	A, Guedes B, Valentim A C, Prieto S, Rodrigues F Noronha (2010). Micro-raman spectroscopy of collotelinite, fusinite and macrinite.Int J Coal Geol, 83(4): 415–422 https://doi.org/10.1016/j.coal.2010.06.002
15	Y Z, Han R T, Xu Q L, Hou J, Wang J N Pan (2016). Deformation mechanisms and macromolecular structure response of anthracite under different stress.Energ Fuel, 30(2): 975–983 https://doi.org/10.1021/acs.energyfuels.5b02837
16	P J F Harris (2005). New perspectives on the structure of graphitic carbons.Crit Rev Solid State Mater Sci, 30(4): 235–253 https://doi.org/10.1080/10408430500406265
17	R, Hinrichs M T, Brown M A Z, Vasconcellos M V, Abrashev W Kalkreuth (2014). Simple procedure for an estimation of the coal rank using micro-Raman spectroscopy.Int J Coal Geol, 136: 52–58 https://doi.org/10.1016/j.coal.2014.10.013
18	J C, Hower J M K, O’Keefe B, Valentim A Guedes (2021a). Contrasts in maceral textures in progressive metamorphism versus near-surface hydrothermal metamorphism.Int J Coal Geol, 246: 103840 https://doi.org/10.1016/j.coal.2021.103840
19	J C, Hower S M, Rimmer M, Mastalerz N J Wagner (2019). Notes on the mechanisms of coal metamorphism in the Pennsylvania anthracite fields.Int J Coal Geol, 202: 161–170 https://doi.org/10.1016/j.coal.2018.12.009
20	J C, Hower S M, Rimmer M, Mastalerz N J Wagner (2021b). Migmatite-like textures in anthracite: further evidence for low-grade metamorphic melting and resolidification in high-rank coals.Geosci Front, 12(3): 101122 https://doi.org/10.1016/j.gsf.2020.12.004
21	L W, Kuo H B, Li S A F, Smith Toro G, Di J, Suppe S R, Song S, Nielsen H S, Sheu J L Si (2014). Gouge graphitization and dynamic fault weakening during the 2008 MW 7.9 Wenchuan earthquake.Geology, 42(1): 47–50 https://doi.org/10.1130/G34862.1
22	B, Kwiecińska H I Petersen (2004). Graphite, semi-graphite, natural coke, and natural char classification—ICCP system.Int J Coal Geol, 57(2): 99–116 https://doi.org/10.1016/j.coal.2003.09.003
23	B, Kwiecinska I, Suarez-Ruiz C, Paluszkiewicz S Rodrigues (2010). Raman spectroscopy of selected carbonaceous samples.Int J Coal Geol, 84(3−4): 206–212 https://doi.org/10.1016/j.coal.2010.08.010
24	B K, Kwiecińska S Pusz (2016). Pyrolytic carbon—definition, classification and occurrence.Int J Coal Geol, 163: 1–7 https://doi.org/10.1016/j.coal.2016.06.014
25	K Li (2019). Investigation on the structural ordering of natural coaly graphite from Xinhua, Hunan Province, China. Dissertation for Doctoral Degree. Beijing: China University of Mining and Technology
26	K, Li Q, Liu S M, Rimmer W W, Huggett S Zhang (2020a). Investigation of the carbon structure of naturally graphitized coals from central Hunan, China, by density-gradient centrifugation, X-ray diffraction, and high-resolution transmission electron microscopy.Int J Coal Geol, 232: 103628 https://doi.org/10.1016/j.coal.2020.103628
27	K, Li Q F, Liu D D, Hou Z G, Wang S Zhang (2021). Quantitative investigation on the structural characteristics and evolution of high-rank coals from Xinhua, Hunan Province, China.Fuel, 289: 119945 https://doi.org/10.1016/j.fuel.2020.119945
28	K, Li S M, Rimmer Q F Liu (2018). Geochemical and petrographic analysis of graphitized coals from central Hunan, China.Int J Coal Geol, 195(April): 267–279 https://doi.org/10.1016/j.coal.2018.06.009
29	K, Li S M, Rimmer Q F, Liu Y M Zhang (2019). Micro-Raman spectroscopy of microscopically distinguishable components of naturally graphitized coals from central Hunan Province, China.Energ Fuel, 33(2): 1037–1048 https://doi.org/10.1021/acs.energyfuels.8b04065
30	K, Li S M, Rimmer S M, Presswood Q F Liu (2020b). Raman spectroscopy of intruded coals from the Illinois basin: correlation with rank and estimated alteration temperature.Int J Coal Geol, 219: 103369 https://doi.org/10.1016/j.coal.2019.103369
31	L, Lu V, Sahajwalla C, Kong D Harris (2001). Quantitative X-ray diffraction analysis and its application to various coals.Carbon, 39(12): 1821–1833 https://doi.org/10.1016/S0008-6223(00)00318-3
32	R J, Nemanich S A Solin (1979). First- and second-order Raman scattering from finite-size crystals of graphite.Phys Rev B Condens Matter, 20(2): 392–401 https://doi.org/10.1103/PhysRevB.20.392
33	M S, Nyathi C B, Clifford H H Schobert (2013). Characterization of graphitic materials prepared from different rank Pennsylvania anthracites.Fuel, 114: 244–250 https://doi.org/10.1016/j.fuel.2012.04.003
34	A Oberlin (1984). Carbonization and graphitization.Carbon, 22(6): 521–541 https://doi.org/10.1016/0008-6223(84)90086-1
35	A Oberlin (2002). Pyrocarbons.Carbon, 40(1): 7–24 https://doi.org/10.1016/S0008-6223(01)00138-5
36	A, Oberlin G Terriere (1975). Graphitization studies of anthracites by high resolution electron microscopy.Carbon, 13(5): 367–376 https://doi.org/10.1016/0008-6223(75)90004-4
37	S, Potgieter-Vermaak N, Maledi N, Wagner Heerden J H P, Van Grieken R, Van J H Potgieter (2011). Raman spectroscopy for the analysis of coal: a review.J Raman Spectrosc, 42(2): 123–129 https://doi.org/10.1002/jrs.2636
38	G, Rantitsch W, Lämmerer E, Fisslthaler S, Mitsche H Kaltenböck (2016). On the discrimination of semi-graphite and graphite by Raman spectroscopy.Int J Coal Geol, 159: 48–56 https://doi.org/10.1016/j.coal.2016.04.001
39	G R Jr, Robinson J M, Hammarstrom D W, Olson G R Jr, Robinson J M, Hammarstrom D W Olson (2017). Graphite.1802J, Reston: VA
40	S, Rodrigues M, Marques I, Suarez-Ruiz I, Camean D, Flores B Kwiecinska (2013). Microstructural investigations of natural and synthetic graphites and semi-graphites.Int J Coal Geol, 111: 67–79 https://doi.org/10.1016/j.coal.2012.06.013
41	J N, Rouzaud D, Deldicque E, Charon J Pageot (2015). Carbons at the heart of questions on energy and environment: a nanostructural approach.C R Geosci, 347(3): 124–133 https://doi.org/10.1016/j.crte.2015.04.004
42	J, Schwan S, Ulrich V, Batori H, Ehrhardt S R P Silva (1996). Raman spectroscopy on amorphous carbon films.J Appl Phys, 80(1): 440–447 https://doi.org/10.1063/1.362745
43	F, Tuinstra J L Koenig (1970). Raman spectrum of graphite.J Chem Phys, 53(3): 1126–1130 https://doi.org/10.1063/1.1674108
44	L, Wang D Y, Cao Y W, Peng Z Y, Ding Y Li (2019a). Strain-induced graphitization mechanism of coal-based graphite from Lutang, Hunan Province, China.Minerals (Basel), 9(10): 1–19 https://doi.org/10.3390/min9100617
45	L, Wang R F, Qin Y, Li H, Zhang (2019b). On the difference of graphitization behavior between vitrinite- and inertinite-rich anthracites during heat treatment.Energ Source, 7036
46	Y, Wang S, Ma T, Shimamoto L, Yao J, Chen X, Yang H, He J, Dang L, Hou T Togo (2014). Internal structures and high-velocity frictional properties of Longmenshan fault zone at Shenxigou activated during the 2008 Wenchuan earthquake.Earth Sci (Paris), 27(5): 499–528 https://doi.org/10.1007/s11589-014-0096-6
47	Y, Wu K, Li Z, Wang M, Hu H, Cao Q Liu (2021). Fluctuations in graphitization of coal seam-derived natural graphite upon approaching the Qitianling granite intrusion, Hunan, China.Minerals (Basel), 11(10): 1147 https://doi.org/10.3390/min11101147
48	J, Xu H, Tang S, Su J W, Liu H D, Han L P, Zhang K, Xu Y, Wang S, Hu Y B, Zhou J Xiang (2017). Micro-Raman spectroscopy study of 32 kinds of Chinese coals: second-order raman spectrum and its correlations with coal properties.Energ Fuel, 31(8): 7884–7893 https://doi.org/10.1021/acs.energyfuels.7b00990
49	L, Yuan Q F, Liu J P, Mathews H, Zhang Y K Wu (2021). Quantifying the structural transitions of Chinese coal to coal-derived natural graphite by XRD, Raman spectroscopy, and HRTEM image analyses.Energ Fuel, 35(3): 2335–2346 https://doi.org/10.1021/acs.energyfuels.0c04019
50	S, Zhang Q F, Liu H, Zhang R J, Ma K, Li Y K, Wu B J Teppen (2020). Structural order evaluation and structural evolution of coal derived natural graphite during graphitization.Carbon, 157: 714–723 https://doi.org/10.1016/j.carbon.2019.10.104
51	Z, Zheng J, Zhang J Y Huang (1996). Observations of microstructure and reflectivity of coal graphites for two locations in China.Int J Coal Geol, 30(4): 277–284 https://doi.org/10.1016/0166-5162(95)00047-X
52	J, Zhu R, Wang P, Zhang C, Xie W, Zhang K, Zhao L, Xie C, Yang X, Che A, Yu L Wang (2009). Zircon U-Pb geochronological framework of Qitianling granite batholith, middle part of Nanling range, south China.Sci China Ser D Earth Sci, 52(9): 1279–1294 https://doi.org/10.1007/s11430-009-0154-4

[1]

Download

[1]	Aikuan WANG, Pei SHAO, Qinghui WANG. Biogenic gas generation effects on anthracite molecular structure and pore structure[J]. Front. Earth Sci., 2021, 15(2): 272-282.
[2]	Chang’an SHAN, Tingshan ZHANG, Xing LIANG, Dongchu SHU, Zhao ZHANG, Xiangfeng WEI, Kun ZHANG, Xuliang FENG, Haihua ZHU, Shengtao WANG, Yue CHEN. Effects of nano-pore system characteristics on CH₄ adsorption capacity in anthracite[J]. Front. Earth Sci., 2019, 13(1): 75-91.

Viewed

Full text

Abstract

Cited

Shared

Discussed