Graphite: Flat, Fibrous and Spherical

Mantle‐derived lherzolitic and harzburgitic Cr‐pyropes from lamprophyres of the Chompolo field (Central Aldan superterrane, North Asian Craton) were studied using micro‐Raman spectroscopy and electron microprobe microanalysis. These garnets enclose graphite coexisting with forsterite, diopside, Ba‐Cl‐phlogopite, tschermakite, rutile, magnesiochromite, Mg‐ilmenite, apatite, chalcopyrite, dolomite, magnesite and lindsleyite inclusions. The PT conditions of residence of graphite‐bearing assemblage in the mantle were estimated, using a combination of mineral thermometers and barometers, to be as high as 2.87–3.55 GPa and 710–770 °C. Generally, graphite within inclusions is well ordered; D1 and D2 disordered bands in its spectra are restricted to inclusion edges. The residual pressure up to 2.1 GPa was inferred for graphite assuming pressure dependence of the G‐band upshift (1580 cm−1 at ambient conditions vs 1588.6 cm−1 at 2.1 GPa). Disordered graphite most likely appears due to the stress‐induced distortion of the fully ordered graphite crystal structure. The distortion results from difference in the thermoelastic properties of graphite inclusions and their garnet hosts exposed to decompression during ascent to the surface with lamprophyre magma. The mineralogy of inclusions in the studied garnets strongly suggests an episode(s) of metasomatism by carbon‐rich agent(s) (COH‐fluid or carbonatitic melt) in the lithospheric mantle of the Central Aldan superterrane, which was coeval with the formation of graphite inclusions and the host pyropes. Copyright © 2017 John Wiley & Sons, Ltd.

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“…Although hexagonal graphite crystals are rare, some inclusions have tabular hexagonal morphology with the prism facets (Figs 3(d) and (4)). [45]…”

Section: Graphite Inclusionsmentioning

confidence: 99%

Graphite‐bearing mineral assemblages in the mantle beneath Central Aldan superterrane of North Asian craton: combined confocal micro‐Raman and electron microprobe characterization

Николенко

Sharygin

Alifirova

et al. 2017

J Raman Spectroscopy

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“…Fibrous (tubular) graphite has been found in artificially produced carbons (Jaszczak 1995) as well as in some meteorites (Mostefaoui et a1. 2005) and igneous rocks (Jaszczak et a1.…”

Section: Introductionmentioning

confidence: 99%

Graphite morphologies from the Borrowdale deposit (NW England, UK): Raman and SIMS data

Barrenechea

Luque

Millward

et al. 2009

Contrib Mineral Petrol

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Graphite in the Borrowdale (Cumbria. UK) deposit occurs as large masses within mineralized pipe-like bodies, in late graphite-chlorite veins, and disseminated through the volcanic host rocks. This occurrence shows the greatest variety of crystalline graphite morphologies rec ognized to date from a single deposit. These morphologies described herein include flakes, cryptocrystalline and spherulitic aggregates. and dish-like forms. Colloform textures. displayed by many of the cryptocrystalline aggregates, are reported here for the first time from any graphite deposit worldwide. Textural relationships indicate that spherulitic aggregates and colloform graphite formed earlier than flaky crystals. This sequence of crystallization is in agreement with the precipitation of graphite from fluids with progressively decreasing supersaturation. The structural characterization carried out by means of Raman spectroscopy shows that, with the exception of colloforrn graphite around silicate grains and pyrite within the host rocks. all graphite morphologies display very high crys tallinity. The microscale SIMS study reveals light stable carbon isotope ratios for graphite (b 13 C = -34.5 to 1. F. Barrenechea . F. 1. Luque (c:;]) .

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“…The morphology of the graphitized carbon was observed to be the same irrespective of the orientation or the magnification. The layered structure and the flaky morphology of graphite is due to its molecular structure which fits into its hexagonal crystallography [ Jaszczak et al, 1995]. The micrograph in Fig 1 b, shows that ZnO has been synthesized on the graphite, as structures which seem like particles or flower grains are seen covering the flaky layered structure of the graphite.…”

Section: Morphological Studies Of Graphite/zinc Oxide Nanocomposite (mentioning

confidence: 87%

Synthesis, Characterisation and Photoelectrochemical Studies of Graphite/Zinc Oxide Nanocomposites with the Application Exfoliated Electrodes for the Degradation of Methylene Blue

O.M¹

2017

IJNME

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Abstract:The search for electrochemically robust materials for electrochemical application in water treatment; we present the preparation of exfoliated graphite which exhibits good electro-photocatalytic propertyand ZnO which possesses high oxygen evolution potential electrodes for the electrochemical degradation of organic pollutants in water. ZnO was prepared by a homogeneous co-precipitation method followed by the preparation of ZnO-exfoliated graphite (EG) electrode. The EG-ZnO electrode was characterized by electron microscopy, Raman spectroscopy, X-ray diffractometry, X-ray photoelectron spectroscopy and electrochemistry. The results showed a good dispersion of the ZnO in the EG and improved potential hole. The EG-ZnO electrode was employed for the electrochemical oxidation of methylene blue dye in synthetic wastewater. The efficiency of degradation was measured by uv-visible spectroscopy and total organic carbon (TOC). The electrode exhibited a higher photodegradation efficiency than the bare EG. The kinetics of this electrochemical reaction was studied using the Langmuir Hinshelwood model. Aside the importance of advance oxidation processes as an alternative or complementary water treatment method, this novel electrode is cheap, easy to prepare and has a robust electrochemistry

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Graphite: Flat, Fibrous and Spherical

Cited by 17 publications

References 54 publications

Graphite‐bearing mineral assemblages in the mantle beneath Central Aldan superterrane of North Asian craton: combined confocal micro‐Raman and electron microprobe characterization

Graphite‐bearing mineral assemblages in the mantle beneath Central Aldan superterrane of North Asian craton: combined confocal micro‐Raman and electron microprobe characterization

Graphite morphologies from the Borrowdale deposit (NW England, UK): Raman and SIMS data

Synthesis, Characterisation and Photoelectrochemical Studies of Graphite/Zinc Oxide Nanocomposites with the Application Exfoliated Electrodes for the Degradation of Methylene Blue

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