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A study of liquids behavior in rotating vessel
Tuhý, Marek ; Šedivý, Dominik (referee) ; Fialová, Simona (advisor)
The presented bachelor thesis deals with the study of liquids behaviour in rotating vessel. The aims of the thesis are theoretical analysis and recherche of the behaviour of liquids in a rotating vessel, design and construction of an experiment, its implementation and evaluation. The hydrostatic knowledge was found in the theoretical part, the practical part was placed in the laboratory of fluid engineering on the assembled experimental track.
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Mineralogy of manganese (hydr)oxides formed by weathering of Mn carbonates at the Kutná Hora ore district
Veselý, Adam ; Drahota, Petr (advisor) ; Tuhý, Marek (referee)
The thesis deals with the geochemisty and mineralogy of manganese oxides and hydroxides. The thesis describes chemical, physical and mineralogical properties of manganese oxide minerals. The main objective of the experimental part of the thesis is to try to identify oxide minerals of manganese, which are formed on carbonate veins in the Kutná ore district. The methods used in the practical part are X-ray diffraction and Raman spectrometry. Most of the studied minerals are characterized by broad diffraction reflections, indicating their low crystallinity. These phases most commonly correspond to the mineral todorokite and less commonly to rancieite, manganite and cryptomelane. In conclusion, it appears that several new mineral species have been identified for the Kutná Hora ore district, but the interpretation of these phases was itself quite problematic and the results contain a considerable degree of uncertainty.
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Anthropogenic particles in soils of historical mining areas
Shalabai, Anastasiia ; Ettler, Vojtěch (advisor) ; Tuhý, Marek (referee)
Soils are an important receptor of anthropogenic contamination. The aim of this bachelor's thesis was to summarize the information about the anthropogenic particles in soils, characterize their chemical and mineralogical composition and find out in which forms the risk elements are found in them. An experimental part of the work was carried out on samples of soils from historical mining and ore processing areas (Jihlava, Příbram) and, for comparison purposes, on an urban soil (Prague - Suchdol) in order to determine the binding of contaminants in particles of anthropogenic origin using a combination of portable X-ray fluorescence (pXRF), optical microscopy, scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA). Dust particles in the studied soils originating from ore mining and processing and burning processes are especially enriched in As, Pb, Zn and Fe. The key contaminants are mainly bound in silicates, glass, oxide phases and sulfides. Iron is also present in the form of metallic droplets. The highest concentration of potentially toxic elements was found in samples from Příbram (mg/kg): As (1514), Pb (7970), Zn (10053). Arsenic was determined in pyrite (up to 2.27 wt.%), which typically is of ore mining. Lead is mostly bound in glass in slag particles (up to 25.12 wt.%...
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Uranium mineralization in the Krkonoše permian piedmont basin: Radioactive elements in the Rudník horizon near Vrchlabí
Novák, Dominik ; Goliáš, Viktor (advisor) ; Tuhý, Marek (referee)
This paper focuses on artificial outcrop of permian lacustrine sediments of the Rudník horizon (298-297 Ma) and red siltstones of the Vrchlabí formation near Vrchlabí, where increased concentrations of uranium and thorium radionuclides were observed during previous researches. Radionuclides are concentrated in a few layers of black, grey and red shales, which makes about 20 m of the whole 250 m long studied profile. Rock samples were collected from localised radioactive layers and studied for mineralogical compositions, concentrations of radionuclides and autoradiographic and microscopic study of uranium and thorium bonds in these rocks. Laboratory measurements confirmed increased concentrations of both uranium and thorium in collected samples. Highest amount of uranium was measured in anoxic black shale (106,9 ppm U), highest amount of thorium in anomalous sample of red siltstone (76,6 ppm Th). Shales and siltstones main contents are albite, analcime, calcite, dolomite, muscovite and potasium feldspars. Acording to the study it is assumed, that the main source of radionuclides were redeposited pyroclastics from the Krkonoše piedmont basin area or synchronous volcanic activity. It is likely, that during late tectonic development of the basin, these radionuclides were redistributed by hydrothermal...
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Thermal behaviour of selected arsenic minerals/phases and its environmental implications
Stonová, Kateřina ; Tuhý, Marek (advisor) ; Drahota, Petr (referee)
iii ABSTRACT This bachelor's thesis focuses on the thermal behaviour of the following arsenic-bearing minerals: enargite (Cu3AsS4), realgar (As4S4), orpiment (As2S3), mimetite [Pb5(AsO4)3Cl] and conichalcite [CaCu(AsO4)(OH)]. Additionally, the behaviour of a synthetic analogue of realgar and an organoarsenic compound (cacodylic acid) was investigated. The experiments were conducted in an argon atmosphere and the temperature range 20-800 řC, with a linear temperature increase. Emissions of arsenic and other elements (S and Pb) were detected using ICP-OES. The thermal behaviour was further analysed by simultaneous DSC and TGA, and the mineralogical composition of the residues was determined by X-ray diffraction analyses. The least stable minerals were realgar and orpiment, melting at 300-320 řC and subsequently releasing arsenic and sulphur (with the highest release at 400-450 řC). Enargite decomposed in the studied temperature range with a 40 % mass loss, emitting the most arsenic and sulphur around 600 řC. Conichalcite also underwent decomposition, losing ca. 3 % of mass and releasing arsenic especially around 700 řC. Mimetite proved the most stable, losing almost no mass and starting to emit arsenic, simultaneously with lead, near the upper limit of the temperature range. The results align with previously...
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Mineralogy of particulates from semi-arid soils polluted by mining and smelting and their transformation/re-mobilization during bushfires
Tuhý, Marek ; Ettler, Vojtěch (advisor) ; Kříbek, Bohdan (referee)
This thesis is focused on biomass-containing topsoils from a highly contaminated semi-arid area in the vicinity of mining and smelting operations in Tsumeb and Kombat in the northern Namibia. The highest concentrations of inorganic contaminants were found in samples from Tsumeb and attained the following values (mg/kg): As 1920, Cd 81, Cu 5840, Hg 7,66, Pb 4880, Sb 266, Zn 3310. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and electron microprobe analysis (EPMA) have been used for determination of mineralogical composition of particulates adhering to surfaces of biomass and occurring in the heavy mineral fraction of topsoils. Quantitative partitioning of contaminants within individual mineral phases has been determined using autoSEM; contaminants were mainly bound in the slag glass (As: 16.7 %; Cu: 12.7 %; Pb: 26.2 %; Zn: 33.9 % of total concentration) and in metal(loid)-rich Fe-hydroxides (As: 14.4 %; Cu: 7.7 %; Pb: 21.6 %; Zn: 32.5 %). On biomass- rich topsoil samples, we have experimentally proved that bushfires can be responsible for transformation and re-mobilization of contaminants. Mercury is completely released at temperatures around 300 řC. In the same temperature range, also As anad Sb are released due to arsenolite (As2O3) thermal degradation. Cadmium is released...
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Radioactive accessory minerals in granitoids and its changes during metamorphosis and alteration.
Tuhý, Marek ; Goliáš, Viktor (advisor) ; Matějka, Dobroslav (referee)
This paper is focused on gathering information about alterations of radioactive accessory minerals in granitic rocks. These minerals become unstable during the influence of fluids and increased temperature and pressure conditions. Allanite is usually metamict therefore it is more easily altered than others. Alteration of monazite is described as decomposing original grains which leads to the formation of secondary minerals such as allanite, apatite, minerals of thorium and epidote. Zircon is the most durable mineral mentioned in this paper. Zircon is altered mainly if it is metamict. Majority of authors agree that during alteration uranium is mobilized into fluids and thorium with REE is incorporate into the secondary minerals.
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Wildfires in polluted areas: mineralogical transformations and remobilization of metal(loid)s
Tuhý, Marek ; Ettler, Vojtěch (advisor) ; Navrátil, Tomáš (referee) ; Campos, Isabel (referee)
Wildfires contribute to the global emissions of trace elements. This Ph.D. thesis focuses on highly polluted areas near smelting/mining polluted sites in Africa, where wildfires are frequent. Experimental samples corresponding to both representative biomass-rich topsoils and grass were investigated using a combination of mineralogical and geochemical methods. Wildfires were simulated using a thermodesorption (TD) technique (75-670 řC; Hg) and newly introduced experimental set-ups (250-850 řC), enabling the online detection of the released contaminants and the sampling the aerosols and ashes. The subsequent investigation revealed the mineralogical and chemical transformations necessary for understanding the temperature- dependent releases of the metal(loid) contaminants during the simulated wildfire. The thermodesorption experiments indicated that >90 % of Hg was released at ~340 řC. A comparison with the Hg reference compounds' TD curves confirmed that the Hg in the biomass- rich topsoils occurs as a mixture of the Hg bound to the organic matter and nanocrystalline black HgS, which exhibited similarities with the TD pattern of smelter flue dust residue. The release of the other metal(loid)s from the topsoils (As, Cd, Cu, Pb, Zn) is dependent on their solid-state speciation, which was determined by...
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