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

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.

Graphical abstract

Keywords

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

References

[1] Bai D Y, Huang J Z, Liu Y R, Wu G Y, Wang X H, (2005). Framework of mesozoic tectonic evolution in southeastern Hunan and the Hunan-Guangdong-Jiangxi border area. Chin Geol, 32(4): 566−570

[2] Beyssac O, Rumble D (2014). Graphitic carbon: a ubiquitous, diverse, and useful geomaterial.Elements, 10(6): 415–420

[3] Blanche C C, Rouzaud J N, Dumas D (1995). New data on anthracite graphitizibility

[4] Bonijoly M, Oberlin M, Oberlin A (1982). A possible mechanism for natural graphite formation.Int J Coal Geol, 1(4): 283–312

[5] Buseck P R, Beyssac O (2014). From organic matter to graphite: Graphitization.Elements, 10(6): 421–426

[6] Buseck P R, Huang B J (1985). Conversion of carbonaceous material to graphite during metamorphism.Geochim Cosmochim Acta, 49(10): 2003–2016

[7] Bustin R M, Ross J V, Rouzaud J N (1995). Mechanisms of graphite formation from kerogen: experimental evidence.Int J Coal Geol, 28(1): 1–36

[8] Chao L I, Wang D H, Zhou L M, Zhao H, Li X W, Qu W J (2017). Study on the Re-Os isotope composition of graphite from the Lutang graphite deposit in Hunan Province. Rock and Mineral Analysis

[9] Duber S, Rouzaud J N, Bény C, Dumas D (1993). Graphitization of anthracites

[10] Eckmann A, Felten A, Mishchenko A, Britnell L, Krupke R, Novoselov K S, Casiraghi C (2012). Probing the nature of defects in graphene by Raman spectroscopy.Nano Lett, 12(8): 3925–3930

[11] González D, Montes-Morán M A, Garcia A B (2003). Graphite materials prepared from an anthracite: a structural characterization.Energy Fuels, 17(5): 1324–1329

[12] Goodarzi F, Eckstrand O R, Snowdon L, Williamson B, Stasiuk L D (1992). Thermal metamorphism of bitumen in archean rocks by ultramafic volcanic flows.Int J Coal Geol, 20(1): 165–178

[13] Guedes A, Valentim B, Prieto A C, Noronha F (2012). Raman spectroscopy of coal macerals and fluidized bed char morphotypes.Fuel, 97: 443–449

[14] Guedes A, Valentim B, Prieto A C, Rodrigues S, Noronha F (2010). Micro-raman spectroscopy of collotelinite, fusinite and macrinite.Int J Coal Geol, 83(4): 415–422

[15] Han Y Z, Xu R T, Hou Q L, Wang J, Pan J N (2016). Deformation mechanisms and macromolecular structure response of anthracite under different stress.Energ Fuel, 30(2): 975–983

[16] Harris P J F (2005). New perspectives on the structure of graphitic carbons.Crit Rev Solid State Mater Sci, 30(4): 235–253

[17] Hinrichs R, Brown M T, Vasconcellos M A Z, Abrashev M V, Kalkreuth W (2014). Simple procedure for an estimation of the coal rank using micro-Raman spectroscopy.Int J Coal Geol, 136: 52–58

[18] Hower J C, O’Keefe J M K, Valentim B, Guedes A (2021a). Contrasts in maceral textures in progressive metamorphism versus near-surface hydrothermal metamorphism.Int J Coal Geol, 246: 103840

[19] Hower J C, Rimmer S M, Mastalerz M, Wagner N J (2019). Notes on the mechanisms of coal metamorphism in the Pennsylvania anthracite fields.Int J Coal Geol, 202: 161–170

[20] Hower J C, Rimmer S M, Mastalerz M, Wagner N J (2021b). Migmatite-like textures in anthracite: further evidence for low-grade metamorphic melting and resolidification in high-rank coals.Geosci Front, 12(3): 101122

[21] Kuo L W, Li H B, Smith S A F, Di Toro G, Suppe J, Song S R, Nielsen S, Sheu H S, Si J L (2014). Gouge graphitization and dynamic fault weakening during the 2008 MW 7.9 Wenchuan earthquake.Geology, 42(1): 47–50

[22] Kwiecińska B, Petersen H I (2004). Graphite, semi-graphite, natural coke, and natural char classification—ICCP system.Int J Coal Geol, 57(2): 99–116

[23] Kwiecinska B, Suarez-Ruiz I, Paluszkiewicz C, Rodrigues S (2010). Raman spectroscopy of selected carbonaceous samples.Int J Coal Geol, 84(3−4): 206–212

[24] Kwiecińska B K, Pusz S (2016). Pyrolytic carbon—definition, classification and occurrence.Int J Coal Geol, 163: 1–7

[25] Li K (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] Li K, Liu Q, Rimmer S M, Huggett W W, Zhang S (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

[27] Li K, Liu Q F, Hou D D, Wang Z G, Zhang S (2021). Quantitative investigation on the structural characteristics and evolution of high-rank coals from Xinhua, Hunan Province, China.Fuel, 289: 119945

[28] Li K, Rimmer S M, Liu Q F (2018). Geochemical and petrographic analysis of graphitized coals from central Hunan, China.Int J Coal Geol, 195(April): 267–279

[29] Li K, Rimmer S M, Liu Q F, Zhang Y M (2019). Micro-Raman spectroscopy of microscopically distinguishable components of naturally graphitized coals from central Hunan Province, China.Energ Fuel, 33(2): 1037–1048

[30] Li K, Rimmer S M, Presswood S M, Liu Q F (2020b). Raman spectroscopy of intruded coals from the Illinois basin: correlation with rank and estimated alteration temperature.Int J Coal Geol, 219: 103369

[31] Lu L, Sahajwalla V, Kong C, Harris D (2001). Quantitative X-ray diffraction analysis and its application to various coals.Carbon, 39(12): 1821–1833

[32] Nemanich R J, Solin S A (1979). First- and second-order Raman scattering from finite-size crystals of graphite.Phys Rev B Condens Matter, 20(2): 392–401

[33] Nyathi M S, Clifford C B, Schobert H H (2013). Characterization of graphitic materials prepared from different rank Pennsylvania anthracites.Fuel, 114: 244–250

[34] Oberlin A (1984). Carbonization and graphitization.Carbon, 22(6): 521–541

[35] Oberlin A (2002). Pyrocarbons.Carbon, 40(1): 7–24

[36] Oberlin A, Terriere G (1975). Graphitization studies of anthracites by high resolution electron microscopy.Carbon, 13(5): 367–376

[37] Potgieter-Vermaak S, Maledi N, Wagner N, Van Heerden J H P, Van Grieken R, Potgieter J H (2011). Raman spectroscopy for the analysis of coal: a review.J Raman Spectrosc, 42(2): 123–129

[38] Rantitsch G, Lämmerer W, Fisslthaler E, Mitsche S, Kaltenböck H (2016). On the discrimination of semi-graphite and graphite by Raman spectroscopy.Int J Coal Geol, 159: 48–56

[39] Robinson G R Jr, Hammarstrom J M, Olson D W, Robinson G R Jr, Hammarstrom J M, Olson D W (2017). Graphite.1802J, Reston: VA

[40] Rodrigues S, Marques M, Suarez-Ruiz I, Camean I, Flores D, Kwiecinska B (2013). Microstructural investigations of natural and synthetic graphites and semi-graphites.Int J Coal Geol, 111: 67–79

[41] Rouzaud J N, Deldicque D, Charon E, Pageot J (2015). Carbons at the heart of questions on energy and environment: a nanostructural approach.C R Geosci, 347(3): 124–133

[42] Schwan J, Ulrich S, Batori V, Ehrhardt H, Silva S R P (1996). Raman spectroscopy on amorphous carbon films.J Appl Phys, 80(1): 440–447

[43] Tuinstra F, Koenig J L (1970). Raman spectrum of graphite.J Chem Phys, 53(3): 1126–1130

[44] Wang L, Cao D Y, Peng Y W, Ding Z Y, Li Y (2019a). Strain-induced graphitization mechanism of coal-based graphite from Lutang, Hunan Province, China.Minerals (Basel), 9(10): 1–19

[45] Wang L, Qin R F, Li Y, Zhang H, (2019b). On the difference of graphitization behavior between vitrinite- and inertinite-rich anthracites during heat treatment.Energ Source, 7036

[46] Wang Y, Ma S, Shimamoto T, Yao L, Chen J, Yang X, He H, Dang J, Hou L, Togo T (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

[47] Wu Y, Li K, Wang Z, Hu M, Cao H, Liu Q (2021). Fluctuations in graphitization of coal seam-derived natural graphite upon approaching the Qitianling granite intrusion, Hunan, China.Minerals (Basel), 11(10): 1147

[48] Xu J, Tang H, Su S, Liu J W, Han H D, Zhang L P, Xu K, Wang Y, Hu S, Zhou Y B, Xiang J (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

[49] Yuan L, Liu Q F, Mathews J P, Zhang H, Wu Y K (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

[50] Zhang S, Liu Q F, Zhang H, Ma R J, Li K, Wu Y K, Teppen B J (2020). Structural order evaluation and structural evolution of coal derived natural graphite during graphitization.Carbon, 157: 714–723

[51] Zheng Z, Zhang J, Huang J Y (1996). Observations of microstructure and reflectivity of coal graphites for two locations in China.Int J Coal Geol, 30(4): 277–284

[52] Zhu J, Wang R, Zhang P, Xie C, Zhang W, Zhao K, Xie L, Yang C, Che X, Yu A, Wang L (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

Acknowledgments

This work is supported by the National Natural Science Foundation of China (Grant Nos. 41672150 and 42002187) and the Scholarship from the China Scholarship Council (No. 201906430017).

Electronic supplementary material

is available in the online version of this article at http://dx.doi.org/10.1007/s11707-021-0967-4 and is accessible for authorized users.

RIGHTS & PERMISSIONS

2022 Higher Education Press