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The main subject of research in this paper is glauconite with its useful parameters, which is the object of exploitation in the "Górka Lubartowska-Niedźwiada" deposit. The main glauconitic horizon (lower Eocene) is built by loamy fine-grained and medium greenish sands with marine fauna and fragments of amber (ca. 7 m thick). Thin lamins and pockets of silts containing phosphorites and also glauconitic sands with underlaying very thin quartz-glauconitic sands are found at the bottom of this layer. The glauconite deposit in "Górka Lubartowska-Niedźwiada" is an amount of ca. 30% by volume of the main glauconitic horizon. Glauconite of the 1M polytype (XRD) shows large granulometric and morphological differentiation (SEM-EDS). It frequently contains aggregations of euhedral or framboidal pyrite grains (RS), which is indicative of the euxinic nature of the formation environment of the rocks under study. The individual glauconite grains show distinct chemical variability, manifested in a lower share of Al2O3 and an increased content of MgO and CaO (EPMA, XRf). At the same time, a large share of K2O (above 8% by weight) allows it to be included in highly matured glauconite, thus it can be considered as a potential raw material for the production of mineral fertilizers. The association of glauconite with phosphates (SEM-EDS) and anatase inclusions in the grains of glauconite (RS) indirectly point to the contribution of the decomposing organic matter to the formation of grains of this mineral. The xylite fragments preserved in the sediment show a low degree of coalification, which is typical of soft lignite. This also shows that the transformation process was taking place under a relatively small overburden. [ABSTRACT FROM AUTHOR]

Xylite very much has the appearance of precious wood species with dark heartwood and also has some physical and aesthetical properties of wood, required nowadays for making valuable products. Xylite, with well recognizable and preserved wood structure, was used for studying the drying kinetics and drying quality. The drying experiments were carried out at 20 °C and 40 °C using constant relative air humidity ranging from 34 % to 87 %, on elements 6 mm, 12 mm and 18 mm thick. The visual assessment of the drying quality was additionally made by light microscopy fracture analysis. The drying time increased with the increase of relative humidity and thickness of specimens. The yield of dry material decreased with the increase of drying time and with the increase of specimen thickness. End-splitting and bowing were the most common drying defects on tangentially oriented specimens. The failure usually occurred in collapsed earlywood, in disoriented tissue or in places with soil or mineral inclusions.

The structure of xylite as lithotype of lignite indicates that it predominately originates from tree stems, from the family Taxodiaceae or Cupressaceae. Despite drastic changes in the long term process of its transformation, it retains some relevant properties of wood, nowadays applicable for specific products. The research examined the influence of moisture content and temperature on modulus of elasticity (MOE) and modulus of rupture (MOR) as well as shear strength and hardness. With decreasing of moisture content, the bending strength and stiffness of xylite increased and was best fitted by power regression model. The increasing of testing temperature from 20 °C to 80 °C had negative effect on stiffness and bending strength of xylite. The hardness was positively correlated with density of xylite, whereas shear strength had the opposite tendency.

The Late Miocene forest was discovered in the opencast lignite mine of Bükkábrány which is situated in the foothills of the Bükk Mountains (NE Hungary). Sixteen stumps were exposed upright in 2007 at their original position. Five stumps were installed in the Ipolytarnóc Fossils Nature Reserve. They are identified in the present paper. The wood of one fossil trunk (No. 1) has been identified as Glyptostroboxylon rudolphii, which represents the wood of Glyptostrobus. Its main microscopic features are: visible growth rings, gradual transition between early- and late wood, rather small opposite bordered pits in 1–2 loosely spaced vertical rows with infrequent crassulae, uniseriate rays formed of procumbent cells without ray tracheids, 1–3 “glyptostroboid” cross-field pits per field and resin canals absent. The four remaining stumps (Nos. 2–5) have been identified as Taxodioxylon germanicum.. Their main microscopic features are: growth rings, abrupt transition between early- and late wood, opposite bordered pits in 1–3 regular vertical rows with frequent crassulae, uniseriate rays formed of procumbent cells without ray tracheids, 1–3 taxodioid cross-field pits per field arranged mostly in one horizontal row, axial parenchyma both in early and late wood (diffuse arrangement) with smooth transverse end walls and resin canals absent. This species most probably represents the wood of Sequoia.

The cross-polarized magic-angle-spinning NMR (CPMAS-NMR) technique was used in this work to assess the carbon distribution in coals of different rank (peat, lignite, xylite, sub-bituminous coal) from important deposits in Greece and Bulgaria. The technique is assumed to be only semiquantitative, due to a number of interferences, such as spinning side bands (SSB) in the spectra, paramagnetic species in the samples, and low or remote protonation of aromatic carbons. The Bulgarian sub-bituminous coal shows the greatest amounts of aromatic structures. The lignite sample from the Drama basin, Northern Greece, is relatively unaltered and largely unweathered, and shows the greatest amounts of aliphatic groups. The 13C-NMR spectra of Pliocene lignites from endemic areas in Serbia and Montenegro and Bosnia, taken from published papers, show significantly more intense resonances for methoxyl, phenolic, and polysaccharide moieties compared to the Drama lignite NMR spectrum. Xylite reveals high contents of carbohydrates.

The depositional palaeoenvironment of the Neogene Achlada lignite deposit (western Makedonia, Greece) was deciphered with respect to the evaluation of the macro-petrographic characteristics, and the data resulted from coal petrographic analyses. The total thickness of the studied lignite seam is ~ 26 m and consists of organic and inorganic alternations. The macro-petrographic observations suggest extremely high contributions of woody-originated tissue (xylite) from a single tree type, among the lignite layers, whereas, numerous in situ stems and trunks were observed. The results of the coal petrographic analysis indicate the dominance of huminite (88.3 vol.%), whereas liptinite and inertinite show much lower values (11.0 vol.% and 0.7 vol.% respectively). High contribution of mineral matter is also observed in many cases. Ulminite types A and B are the most abundant macerals, whereas the content of ulminite B is followed by the xylite content. Facies modeling using maceral composition and maceral indices suggested the alternation of forest swamp and reed-moor environments where peat accumulated under highly-saturated and intensely-anoxic conditions. A terrestrial origin with wet forest to piedmont plain depositional conditions was suggested by the Gelification Index (GI) and Tissue Preservation Index (TPI) plot. A cross-plot of the ground water index (GWI) vs. the vegetation index (VI) suggested swamps under mesotrophic and rheotrophic hydrogeological conditions, where the dominant source for the peat was woody vegetation and vegetation high in preservation potential. The overall macro and micro characteristics of the Achlada lignite suggest a depositional palaeoenvironment that includes three independent parts: a) the main channel of a meandering river system; b) the floodplain area; and c) the oxbow lake. The establishment of telmatic/limnotelmatic conditions in this palaeoenvironment resulted in the formation of the entire Achlada lignite deposit, whereas numerous flood episodes interrupted the peat accumulation and resulted in the deposition of clay-rich sediments. [ABSTRACT FROM AUTHOR]

The experiments were performed to obtain high purity raw material for activated carbon making, by mechanical preparation of xylite recovered from the Oltenia lignite Basin. The study analyzes the most important parameters that involves the selective grinding of a representative amount of 15.7 t xylite (moisture, mineral content, botanic origin), using a production equipment (a hammer-crusher of 50 t/h) and the yields and characteristics of the fractions obtained for the activated carbon manufacturing, with high usage value. The key objectives of this study are: (1) to establish yields and quality of the fractions obtained by processing a representative amount of xylite; (2) to reveal the decisive role of the preparation stages on the characteristics of the final product; and (3) to reveal the occurrence, selection methods and preliminary assessment of the xylite reserves necessary for designing a capacity for activated carbon commercial-scale processing unit. This paper presents the results obtained at semi-industrial level of xylite preparation (by crushing and volumetric classifying), for obtaining structural unchanged variety sizes suitable for experiments to obtain activated carbon. It was proved that selective crushing and sieving is a very effective technique taking into account also obtaining the convenient output (yields of over 80%) of useful fraction of xylite (greater than 10 mm with an ash between 2.0 and 2.5%). The results point out that the higher the selection and preparation go, the more lower the ash in the upper grain size fractions. The xylite fractions represent an appropriate raw material used for activated carbon making, characterized by a pore volume of 0.32 cm 3 /g, developed mainly in the range of very narrow pores (over 70% under 10 Å) which give high surface area BET up to 800 m 2 /g for granular type, the average radius of open pores being 6–9 Å. [ABSTRACT FROM AUTHOR]

Xylite, a by-product of lignite production, can be converted into fuel pellets by using a wet pelletizing process, in which the drying step of the raw pellets is of vital importance. During moisture removal, structural changes take place in the agglomerates, they become harder and investigations of the drying behavior indicate high shrinkage during drying. This effect can also be seen in hygroscopic sorption experiments. Furthermore, the pellets show two drying sections. The main factor affecting the drying speed is the temperature; the pellet composition has a subsidiary effect. [ABSTRACT FROM AUTHOR]

This work presents an original method and an automated installation to recover by combustion the waste gas obtained in the ignition process of xylites in rotary kiln. The flue gas resulting from the combustion of waste gas, with light fuel support are used in the technological processes of obtaining activated carbon, satisfying the conditions where the oxygen content does not exceed 0.3% vol. and the temperature is above 1200°C, conditions imposed by the Project Manager of the European project LIFE 02. Our automated installation consists in a combustion chamber and a heat exchanger, which along with a rotary kiln and an activation reactor build the technological installation called "ENVACTCARB" of this project. The design of our automated installation was done by running a computer program in order to calculate the combustion parameters and based on material and energy balances. The experiments were carried out in two stages: preliminarily, to characterize the liquid fuel combustion in the pilot installation and secondary, in the technological installation. The preliminary experimental results, presented as a comparison between the variants of light fuel burning, with and without using additives, show getting a complete combustion having low emission of pollutants and the oxygen content not exceeding 0.3% volumes. The experimental results performed in the technological installation certified the use of the automated installation for waste gas recovery through combustion. [ABSTRACT FROM AUTHOR]

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Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The FT-IR spectra for both Neogene xylite and matrix lignite samples from six different Greek lignite deposits (NW Greece) show significant differences. In particular in the aliphatic stretching region (3000–2800cm−1) the intensities of the vibrations are more prominent in the xylite lithotype as in the matrix lignite lithotype. The intense bands in the region 3402–3416cm−1 are attributed to −OH stretching of H2O and phenol groups for both xylite and matrix lignite lithotypes. The bands at ~3697cm−1 and ~3623cm−1 as well as at ~538cm−1 and 470cm−1, which are more evident in the FT-IR spectra of the matrix lignite, are attributed to a higher clay content in the samples of this lithotype. Data resulting from X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and thermoanalytical methods (TG/DTG and DTA) indicate main differences of the xylite and matrix lignite lithotype as well. Typical peaks in X-ray diagrams confirm the high content of clay minerals in matrix lithotype, and their minor contribution in the xylite lithotype. Scanning electron microscopy (SEM), combined with the FT-IR and XRD results, reveals prevalence of gypsum, pyrite/marcasite, quartz, and clays in the matrix lignite lithotype as compared with the xylite lithotype and also textural differences such as the heterogeneity in the mass of matrix lignite and the homogeneity of the xylite. Compositional differences of the examined lignite materials, as identified by FT-IR, were also confirmed by TG/DTG/DTA. While cellulose decomposition was observed by an endothermic peak of DTA curves, at around 360°C, in the xylite samples, lignin degradation became a prominent process observed in the temperature range from 200°C to 400°C in the matrix lignite samples. This was also observed by an exothermic peak on DTA curves. Each of the heat effects was accompanied with a partial mass loss registered on TG curves. As a whole, the data resulting from the combined research by means of FT-IR, XRD, SEM, and TG/DTG/DTA of both xylite and matrix lignite lithotypes confirm the significant differences between these two lignite lithotypes reflecting their different structure, texture, and maturity stage. [ABSTRACT FROM AUTHOR]

Abstract: Numerous coalified tree stumps remained preserved in-situ in the so-called “Stump Horizon” (the palaeontologic horizon No. 31), which represents clayey overburden of the main coal seam in the Bílina open cast mine in the Most Basin (Czech Republic). The petrological and chemical composition, palaeobotanical origin and preservation of 24 selected tree stumps were studied by optical and scanning electron microscopy and gas chromatography–mass spectrometry (GC–MS). Composition of the fossil wood is dominated by ulminite, particularly texto-ulminite B. Textinite forms up to 38vol.% in the decomposed tree stumps. Corpohuminite dominates in bark and root tissues. Partly gelified and deformed woody tissues contain both corpohuminite and resinite fillings. Random reflectance of ulminite ranges from 0.33% to 0.39% and carbon content from 49wt.% to 78wt.%. Samples represent pure woody material with small admixtures of clay minerals, siderite, and very rare pyrite. Observations by scanning electron microscopy revealed various levels of deformed secondary xylem with more or less swollen cell walls, conspicuous tracheids, uniseriate rays of a different height, and round or cylinder-like resin or corpohuminite bodies. According to our results and other published data the wood might belong to Glyptostroboxylon and Taxodioxylon genera that are supposed to belong to Glyptostrobus and Quasisequoia plants respectively, representatives of the coniferous family Cupressaceae. The biomarker composition in the extracts of the fossil wood includes sesquiterpenoids (α-cedrane, drimane, eudesmane), diterpenoids (abietane, fichtelite, 16α(H)-phyllocladane) and their degraded compounds. The terpenoids are derived from precursors produced by the source plants and microorganisms. The terpenoid signatures support a relationship to the Cupressaceae family with input of microbial species. These characteristics were identical for all studied samples. Significant variations have been observed in sesquiterpenoid α-cedrane and diterpenoid 16α(H)-phyllocladane contents. [Copyright &y& Elsevier]

This study focuses on the origin and properties of the Oltu gemstone or Oltustone. The Oltu gemstone known as 'Black Amber' is dull-bright black color, and is very low ash, high volatile matter, total sulfur and calorific value. Very high volatile matter content on a dry-ash free basis (66.52%) and non-agglomerating character imply that its coal rank is very low. The Oltu gemstone includes abundant organic (amorphous) matter and trace amounts of quartz and pyrite. Petrographic study indicated that pyrite and quartz generally finely disseminated the organic matter. Major and trace element data have low concentrations. The trace element concentrations fall within the range values for the most world coals, except for Bi that exceeds range values (0.1-0.5 μg/g) in most world coals. Petrographic observations on the polished briquette have shown that the gemstone was made of xylite including mainly textinite and corpohuminite, minor amounts of resinite and liptodetrinite. Mean values of random reflectance (%Rr) measurements on the textinite and corpohuminite are 0.23 and 0.30%Rr, respectively. These values indicate very low coal rank, in agreement with the volatile matter. [ABSTRACT FROM AUTHOR]

Abstract: Xylites are promising materials for activated carbon manufacturing due to their low rank, low inorganic content, and structural characteristics similar to the strong consistence of wood. These are similar to the classical adsorbents used for waste water purification, and available and profitable in the long term. This study has been undertaken to provide by means of petrographic data, new information on the porous structure development in chars during direct heating carbonization and physical activation. The xylite petrographic composition is very important, mainly due to the existence of structured wooden material – textinite with round and elongated cells – that influences the development of the structure and texture during carbonization and activation. The charcoal microstructure reveals some interesting aspects about the carbonization process with regard to evolution, efficiency and pore development. In the xylite activated carbon, the adsorption surface development by means of the highly porous system depends on the type of petrographical components, raw material grain size, and carbonization parameters. [Copyright &y& Elsevier]

Abstract: Miocene conifer wood samples from the Belchatow brown coal deposit in Poland were studied in order to discuss a range of chemical variations that occur as a result of biochemical coalification. Petrographic analysis, ultimate analysis, electron microprobe technique, and FTIR spectroscopy were used in this study. Our data show several progressive trends in functional groups distribution that take place during the wood transformation from group 1 to group 4, such as an overall increase in aromaticity, an increase in lignin/cellulose ratio, and an increase in oxygen functionalities. Other observations include an increase in aliphatic stretching and bending functionalities from groups 1 to 3; followed by a decrease in the wood of group 4; appearance of aliphatic out-of-plane bands in group 3 and increase in group 4; an increase in CH2 /CH3 in group 4 compared to the other groups; and decrease in O–H groups in group 4 compared to other groups. These observations, together with other chemical and petrological observations, indicate that the progressive elimination of cellulose and modification of lignin are dominant processes of the wood transformation. [Copyright &y& Elsevier]

Fourier transform infrared (FTIR) spectra of lignite and humic clay samples, collected from 2 boreholes located at Apofysis-Amynteo lignite deposit, NW Greece, as well as their insoluble organic matter, obtained by Soxhlet extraction with dichloromethane, were recorded between 400 and 4,800 cm -1 . In the same way, FTIR spectroscopy was used to study a xylite sample from Vevi xylite basin (north of Apofysis-Amynteo lignite deposit) and its chars, which are the solid products of pyrolysis, at 3 final fixed temperatures: 400°C, 600°C, and 800°C. In the Apofysis-Amynteo samples, oxygen-containing structures were observed in the 1,800-1,000 cm -1 zone, aliphatic hydrogen in the 2,950-2,700 cm -1 zone, aromatic out-of-plane structures in the 900-670 cm -1 zone, and hydroxyl groups in the 3,400-3,600 cm -1 zone. A great abundance of C=O and C-O-R structures in the 1,800-1,000 cm -1 region were noticed, while clay and silicate minerals were identified in the 400-600 cm -1 and 3,600-3,800 cm -1 zones. In the IR spectra of the initial xylite sample BEX, the major quantity of H 2 O is at a wave number of 3,400 cm -1 . A strong peak at 1,032 cm -1 in the xylite sample is evidence of the presence of phenolic and alcoholic C-O bonds as well as C-O-C bonds with aliphatic or aromatic carbons. The 800°C char, at the same wave number, presents only a weak peak. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results on the Hardgrove and Bond grindabilities of the Hungarian lignite and its isolated textural components. It is shown that for such heterogeneous materials as lignites, the Hardgrove grindability index can be used only as a quantitative feature. Nevertheless the Bond-work index is the genuine grindability parameter. A Smith formula for re-calculating the Bond-work index from the Hardgrove grindability is also analysed. A new self-developing algorithm for the simulation of Bond grindability is introduced: this algorithm fits the experimental data better than the ones proposed earlier and, at the same time, has shorter testing times. It was proved experimentally that selective grinding was a very effective technique for producing an advanced solid fuel or other products with low ash and high humic acid contents from lignites having a high tendency for size degradation. The paper also deals with the theoretical and experimental possibilities of the further improvement of the advanced lignite product by steam dehydration. [Copyright &y& Elsevier]

Trace and rare earth element concentrations were determined in 18 lignite and xylite samples from the three horizons of the Lava mine, Servia basin, Northern Greece. Low concentrations (mostly < 50 ppm) of B suggest that the deposits developed under fresh water influence. Very few elements (As, Ag, Cd, U, Se, and Te) can be considered as enriched when compared to Earth's crust averages. The elements Li, Be, Ti, Cr, Ga, Rb, Sr, Zr, Nb, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Hf, Tl, Pb, Th, and Sc show a great affinity to the ash, while an intermediate affinity is shown by the elements B, V,Co, Ge, Mo, Cd, Sb, Ta, U, and W.A calm, low-energy limnic depositional environment is considered for the first and the third horizons, while for the second horizon, a telmatic to fluvial depositional environment with a very strong terrestrial impact is suggested. The positive Ce anomalies could reflect a relatively reducing environment of formation. [ABSTRACT FROM AUTHOR]

The present research compares the yield of microbial methane production from different lithotypes of Miocene lignite from the Konin Basin in Poland and attempts to establish an understanding of the processes responsible for methanogenesis. A series of batch experiments were carried out with detritic and xylitic lignites inoculated with microorganisms from an external source (the anaerobic chamber of a wastewater treatment plant in a sugar factory). Biogas volume, concentration and stable carbon isotopes of microbial methane were measured. It was found that detritic lignites are a slightly more suitable raw material for microbial methane production than xylites. Methane yield for detritic lignites equalled 14.3 μmol CH 4 /g of total organic carbon (TOC); for xylites, 13.7 μmol CH 4 /g of TOC. The mean δ13C(CH 4) value in experiments with detritic coal from Konin equalled −36.3‰; for fossil wood fragments, −47.3‰ and −42.7‰. We suppose that differences in mean δ13C(CH 4) values from the biodegradation of different lithotypes of lignite from the Konin Basin most probably depend on cellulose and lignin content (%). The holocellulose content in xylites decreased over time, suggesting the important role of the enzymatic hydrolysis of cellulose to glucose. Methane from detritic lignite was formed due to lignin decomposition. Methane-producing microbial communities were dominated by Bacteria mainly from the phyla Proteobacteria (Alpha-, Beta- and Gamma- or Deltaproteobacteria), Firmicutes (Clostridia and Bacilli), Actinobacteria , and Bacteroidetes. Archaea constituted only 2–6% of the microbial community, including Methanosarcinales , Methanomicrobiales , and Methanobacteriales. The data presented here show no clear correlations between lignite type and specific bacterial or archaeal taxa. However, certain tendencies were observed. Exiguobacterium and Pseudomonas are more abundant in xylites, Rhizobacteriaceae in detritic lignites. This indicates the complexity and diversity of lignite material and processes leading to lignite degradation. In the presented research model, anaerobic oxidation of methane may occur. • Biodegradation of different lithotypes of Miocene lignites from the Konin Basin, Poland • Similar biogas and methane yield in experiments with detritic lignites and xylites • Exiguobacterium and Pseudomonas more frequent in xylites, Rhizobiaceae in detritic lignites. • Possible anaerobic oxidation of methane while lignite incubation [ABSTRACT FROM AUTHOR]