Coalification and coal alteration under mild thermal conditions
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985891%3A_____%2F18%3A00495807" target="_blank" >RIV/67985891:_____/18:00495807 - isvavai.cz</a>
Result on the web
<a href="http://dx.doi.org/10.1007/s40789-018-0220-7" target="_blank" >http://dx.doi.org/10.1007/s40789-018-0220-7</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1007/s40789-018-0220-7" target="_blank" >10.1007/s40789-018-0220-7</a>
Alternative languages
Result language
angličtina
Original language name
Coalification and coal alteration under mild thermal conditions
Original language description
Coalification temperatures are often considered to be approximately 100–170 °C for bituminous coal and 170–275 °C for anthracite. However, our micropetrographic observations, solid state 27Al magic-angle spinning nuclear magnetic resonance measurements, interpretation of δ13C values for whewellite in pelosiderite concretions from Carboniferous sediments, and assessment of whewellite thermal stability show that coalification temperatures can be significantly lower. Also the temperatures of coal alteration may be substantially lower than is stated. Ordinarily, high-temperature alteration is reported, but microthermometric measurements of fluids temperatures and micropetrographic observations show that the coal alteration can take place at low temperatures. For this reason, coals from the Kladno–Rakovník Basin, part of Late Paleozoic continental basins of the Czech Republic, were analyzed. Regarding coalification, micropetrographic characterizations of unaltered coals, the presence of thermally unstable Al complexes in the coal organic mass documented using 27Al MAS NMR method, and proven occurrence of whewellite in pelosiderite concretions suggest a lower coalification temperature, max. ~ 70 °C. Regarding coal alteration, micropetrographic observations revealed (a) the weaker intensity of fluorescence of liptinite, (b) mylonitic structures and microbreccia with carbonate fluid penetration, and (c) high oxygen content in coals (37–38 wt.%). These phenomena are typical for thermal and oxidative alteration of coal. As the temperature of carbonate fluids inferred from fluid inclusion analysis was evaluated as ~ 100–113 °C, the temperature of coal alteration was suggested as ~ 113 °C, the alteration was caused by hot hydrothermal fluids.
Czech name
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Czech description
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Classification
Type
J<sub>SC</sub> - Article in a specialist periodical, which is included in the SCOPUS database
CEP classification
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OECD FORD branch
10505 - Geology
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
International Journal of Coal Science & Technology
ISSN
2095-8293
e-ISSN
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Volume of the periodical
5
Issue of the periodical within the volume
3
Country of publishing house
CH - SWITZERLAND
Number of pages
16
Pages from-to
358-373
UT code for WoS article
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EID of the result in the Scopus database
2-s2.0-85054616345