Priciples of Polish hard coals data base organization worked out by Carbochemistry Department of ... more Priciples of Polish hard coals data base organization worked out by Carbochemistry Department of Polish Academy of Science were presented. The first of developed data systems, called IKAR, contains the properties of Polish hard coals. The second one under the name WEGIEL is supplementary to the first one and collects more than 500 Polish and foreign publications on coal analysis and processing
The methods of the theory of an effective medium and that of percolation were used to study the l... more The methods of the theory of an effective medium and that of percolation were used to study the laws of the change in the permittivity of coal saturated with carbon dioxide depending on the gas pressure when the latter approaches the threshold of capillary-like condensation of the gas in the coal. The established laws confirm the fractal nature of the structure of the sorbing surface of the coal. Its dimension determined by these data is consistent with the value of this quantity found from the results of studying the electrical conductivity of coal saturated with a gas, including under conditions of capillary-like condensation of sorbate in the coal.
The results of studying coal clays by optical microscopy, EPR, and IR spectroscopy are presented.... more The results of studying coal clays by optical microscopy, EPR, and IR spectroscopy are presented. A scheme for their complex processing is proposed.
Abstract The effect of a magmatic intrusion on the optical properties (reflectance, anisotropy an... more Abstract The effect of a magmatic intrusion on the optical properties (reflectance, anisotropy and optical character) of vitrinite in low-rank bituminous coals was examined. The study focused on coal samples collected at different distances from an intrusion emplaced into seam no. 416 in Sośnica mine near Gliwice in the Upper Silesian Coal Basin, Poland. In the immediate contact zone, coal transformed into natural coke may be seen. For comparison, laboratory carbonization of coals weakly changed or apparently unchanged by the intrusion was carried out. The results obtained confirmed that during carbonization of the low-rank coal, heating alone (with no external pressure) makes possible the reorganization of carbon planes that is responsible for the increase of vitrinite reflectance. The heating leads to the destruction of coal-structure cross-linkages (aliphatic groups or heteroatoms) and various further transformations of the structural net, in addition to the removal of volatile carbonization products. External pressures affect the transformation process, especially by promoting the rearrangement of small structural units to form further elements of anisotropic structure. Thus, in the case of coal from the immediate contact of the intrusion, pressures resulted in values of anisotropy parameters higher than those characterizing coal heated in the laboratory up to 1200 °C, but in the absence of stress. The source of pressure that strongly affected the coal in the mine was probably intrusion related. Weak tectonism in the region of the Sośnica mine could explain the fine biaxial optical character of the low rank parent coals more generally. Pressures associated with thermally evolving gasses conceivably led to the growth of structural anisotropy in the walls of degassing pores. Finally, some structural changes seen in coal adjacent to the intrusion may reflect hydrothermal activity.
EPR studies are performed for coal and its products of extraction with tetrahydrofurane /THF/, py... more EPR studies are performed for coal and its products of extraction with tetrahydrofurane /THF/, pyridine /Py/ and ethylenediamine /EtDA/. The spectra of the coal and the residues after extraction consisted of two lines, the one broad and the other narrow. Their intensities depend differently on the temperature of measurement. The system of paramagnetic centers related with the narrow line obeys the Curie law /S = 1/2 /, whereas that related with the broad line does not, and consists of free radicals /S = 1/2/and of centers with singlet ground state /S = 0/ and lowest excited triplet state /S = 1/. Quenching of paramagnetic centers during extraction is found to be related with the destruction of inter-molecular bonds of the electron donor-acceptor type between the two molecular phases in coal.
THE MICROTEXTURE AND MICROSTRUCTURE OF COKES PREPARED WITH CALCIUM HYDROXIDE ADDITIVES The influe... more THE MICROTEXTURE AND MICROSTRUCTURE OF COKES PREPARED WITH CALCIUM HYDROXIDE ADDITIVES The influence of the chemical modification of coal on the structure, microstructure, and properties of coke is shown. The use of optical and X-ray structural methods of analysis made it possible to determine the action of a calcium hydroxide additive on the structure of samples. It was found that in the presence of an additive, the total content of lamellas, the content of flat ones (transmission electron microscopy), and the amount of a fluid domain texture (optical microscopy) increase together with an increase in the thickness of the pore walls in the relevant cokes.
Glass-like carbon is a well known carbon form that still poses many challenges for structural cha... more Glass-like carbon is a well known carbon form that still poses many challenges for structural characterization owing to a very complex internal atomic organization. Recent research suggests that glassy carbon has a fullerene-related structure that evolves with the synthesis temperature. This article reports on direct evidence of curved planes in glassy carbons using neutron and X-ray diffraction measurements and their analysis in real space using the atomic pair distribution function formalism. Changes in the structure including the degree of curvature of the non-graphitizing glassy carbons as a function of the pyrolysis temperature in the range 800–2500°C (1073–2773 K) are studied using optimized models of the atomic structure. Averaged models of single coherent scattering domains as well as larger structural fragments consisting of thousands of atoms were relaxed using classical molecular dynamics. For such models the diffraction intensities and the pair distribution functions wer...
A series of porous carbon materials, produced by pyrolysis of saccharose and anthracene and heat-... more A series of porous carbon materials, produced by pyrolysis of saccharose and anthracene and heat-treated at 1000°C, 1900°C and 2300°C have been studied by wide-angle X-ray scattering. The X-ray data were collected at European Synchrotron Radiation Facility (ESRF) in Grenoble on the ID 15 beam line (high-energy X-ray diffraction) using the wavelength λ,=0,1067 (E=116,2 keV). The data were recorded in
Priciples of Polish hard coals data base organization worked out by Carbochemistry Department of ... more Priciples of Polish hard coals data base organization worked out by Carbochemistry Department of Polish Academy of Science were presented. The first of developed data systems, called IKAR, contains the properties of Polish hard coals. The second one under the name WEGIEL is supplementary to the first one and collects more than 500 Polish and foreign publications on coal analysis and processing
The methods of the theory of an effective medium and that of percolation were used to study the l... more The methods of the theory of an effective medium and that of percolation were used to study the laws of the change in the permittivity of coal saturated with carbon dioxide depending on the gas pressure when the latter approaches the threshold of capillary-like condensation of the gas in the coal. The established laws confirm the fractal nature of the structure of the sorbing surface of the coal. Its dimension determined by these data is consistent with the value of this quantity found from the results of studying the electrical conductivity of coal saturated with a gas, including under conditions of capillary-like condensation of sorbate in the coal.
The results of studying coal clays by optical microscopy, EPR, and IR spectroscopy are presented.... more The results of studying coal clays by optical microscopy, EPR, and IR spectroscopy are presented. A scheme for their complex processing is proposed.
Abstract The effect of a magmatic intrusion on the optical properties (reflectance, anisotropy an... more Abstract The effect of a magmatic intrusion on the optical properties (reflectance, anisotropy and optical character) of vitrinite in low-rank bituminous coals was examined. The study focused on coal samples collected at different distances from an intrusion emplaced into seam no. 416 in Sośnica mine near Gliwice in the Upper Silesian Coal Basin, Poland. In the immediate contact zone, coal transformed into natural coke may be seen. For comparison, laboratory carbonization of coals weakly changed or apparently unchanged by the intrusion was carried out. The results obtained confirmed that during carbonization of the low-rank coal, heating alone (with no external pressure) makes possible the reorganization of carbon planes that is responsible for the increase of vitrinite reflectance. The heating leads to the destruction of coal-structure cross-linkages (aliphatic groups or heteroatoms) and various further transformations of the structural net, in addition to the removal of volatile carbonization products. External pressures affect the transformation process, especially by promoting the rearrangement of small structural units to form further elements of anisotropic structure. Thus, in the case of coal from the immediate contact of the intrusion, pressures resulted in values of anisotropy parameters higher than those characterizing coal heated in the laboratory up to 1200 °C, but in the absence of stress. The source of pressure that strongly affected the coal in the mine was probably intrusion related. Weak tectonism in the region of the Sośnica mine could explain the fine biaxial optical character of the low rank parent coals more generally. Pressures associated with thermally evolving gasses conceivably led to the growth of structural anisotropy in the walls of degassing pores. Finally, some structural changes seen in coal adjacent to the intrusion may reflect hydrothermal activity.
EPR studies are performed for coal and its products of extraction with tetrahydrofurane /THF/, py... more EPR studies are performed for coal and its products of extraction with tetrahydrofurane /THF/, pyridine /Py/ and ethylenediamine /EtDA/. The spectra of the coal and the residues after extraction consisted of two lines, the one broad and the other narrow. Their intensities depend differently on the temperature of measurement. The system of paramagnetic centers related with the narrow line obeys the Curie law /S = 1/2 /, whereas that related with the broad line does not, and consists of free radicals /S = 1/2/and of centers with singlet ground state /S = 0/ and lowest excited triplet state /S = 1/. Quenching of paramagnetic centers during extraction is found to be related with the destruction of inter-molecular bonds of the electron donor-acceptor type between the two molecular phases in coal.
THE MICROTEXTURE AND MICROSTRUCTURE OF COKES PREPARED WITH CALCIUM HYDROXIDE ADDITIVES The influe... more THE MICROTEXTURE AND MICROSTRUCTURE OF COKES PREPARED WITH CALCIUM HYDROXIDE ADDITIVES The influence of the chemical modification of coal on the structure, microstructure, and properties of coke is shown. The use of optical and X-ray structural methods of analysis made it possible to determine the action of a calcium hydroxide additive on the structure of samples. It was found that in the presence of an additive, the total content of lamellas, the content of flat ones (transmission electron microscopy), and the amount of a fluid domain texture (optical microscopy) increase together with an increase in the thickness of the pore walls in the relevant cokes.
Glass-like carbon is a well known carbon form that still poses many challenges for structural cha... more Glass-like carbon is a well known carbon form that still poses many challenges for structural characterization owing to a very complex internal atomic organization. Recent research suggests that glassy carbon has a fullerene-related structure that evolves with the synthesis temperature. This article reports on direct evidence of curved planes in glassy carbons using neutron and X-ray diffraction measurements and their analysis in real space using the atomic pair distribution function formalism. Changes in the structure including the degree of curvature of the non-graphitizing glassy carbons as a function of the pyrolysis temperature in the range 800–2500°C (1073–2773 K) are studied using optimized models of the atomic structure. Averaged models of single coherent scattering domains as well as larger structural fragments consisting of thousands of atoms were relaxed using classical molecular dynamics. For such models the diffraction intensities and the pair distribution functions wer...
A series of porous carbon materials, produced by pyrolysis of saccharose and anthracene and heat-... more A series of porous carbon materials, produced by pyrolysis of saccharose and anthracene and heat-treated at 1000°C, 1900°C and 2300°C have been studied by wide-angle X-ray scattering. The X-ray data were collected at European Synchrotron Radiation Facility (ESRF) in Grenoble on the ID 15 beam line (high-energy X-ray diffraction) using the wavelength λ,=0,1067 (E=116,2 keV). The data were recorded in
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