The relation between the lithotypes of Pliocene coals from Oltenia and their main quality characteristics
Bulletin of Geosciences, volume 74, issue 2;
pages: 169 - 174;
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The main Pliocene lignite lithotypes from Oltenia (detrital coal, xylite, xylite coal, weakly xylite coal, clayey coal) were formed within various coal facies named after the dominant paleophytocoenoses: the forest with Sequoia, the grassy swamp (Carex ssp.), the decidous forest swamp, the forest swamp with Glyptostrobus, the marsh with Phragmites and the aquatic plants prairie. In each of these coal facies 1-3 lignite lithotypes were formed. Due to the fact that the chemistry of the parental vegetal material was sensibly different with regard each community and that this parental vegetal material was accumulated within different environmental conditions, the resulted lithotypes present specific properties. In this paper are the following parameters are approached: ash, hygroscopic moisture, volatile matter, calorific value, combustible sulfur. Moreover, the main characteristics of the xylite lithotype are analysed. Xylite, by its properties (primary carbonification products, benzene-alcohol extract, pore structure, carbon content, etc.) represents a valuable lithotype as a prime matter source.