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Increasing the whiteness of kaoline
Bartošík, Jan ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The thesis deals with the issue of increasing the whiteness index of kaolin raw material. The research was focused on floating the kaolin suspension and the subsequent processes related to increasing the whiteness index. Increasing the whiteness of the kaolin raw material took place on the basis of acid leaching. The eluents were based on sulfuric acid, phosphoric acid, oxalic acid and sodium bisulfite. The leaching process was influenced by the temperature and concentration of the leaching agent. Floated and leached kaolin samples were characterized by several methods. The XRD method investigated the mineralogical composition and the kaolinite structure order. The distribution of chromogenic components was monitored by SEM-EDS. Residues of organic matter was determined by COD test and the concentration of chromogenic components in the extract was monitored by the ICP-OES method. Last but not least, the index of whiteness was measured, the increase of which is the aim of the diploma thesis, using a UV-VIS spectrometer with reflective extension.
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Heat insulating moulded refractory materials
Novotný, Radoslav ; Lang, Karel (referee) ; Raschman,, Pavel (referee) ; Havlica, Jaromír (advisor)
Doctoral thesis is focused on the study, research and development of heat insulating moulded refractory materials. The replacement of shaped instead of unshaped refractories is recently and strongly industrially demanded and belongs to ongoing research topics. With the increasing demand of energy savings, the excellent insulation properties are essential. The insulating properties of castables are the result of targeted porosity formation. The porosity is coming from the controlled air intrusion into material resulted to foamed structure. The foaming process was achieved by mixing of separately prepared aqueous foam into raw castable slurry or by in situ foaming of intensively mixed castable slurry with the surfactant additive. Nevertheless, the study of foam behaviour and the influence of additives on binder hydration and setting processes (i.e. calciumaluminate cement) was substantial for successful preparation of the experimental samples. The two types of the experimental samples were prepared. The first one was based on mixing of kaolin slurry with pre-prepared aqueous foam, whereas the de-aglomeration ability of kaolin specie was utilized to water-particle film formation. In situ foaming of multicomponent system is the second one. The both processes brought some negative attributes, so the optimal properties of prepared castables were achieved by their combination.
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Kinetics of Heterogeneous Processes in Silicate Technologies -Dehydroxylation and Disolution of Clay Minerals
Křečková, Magdaléna ; Kutzendörfer, Jaroslav (referee) ; Kuřitka, Ivo (referee) ; Havlica, Jaromír (advisor)
The first part of the thesis discuss general characterization of heterogeneous processes in silicates. This part is focused on kinetics of heterogeneous processes and mathematical description of reactions time behavior. The other part describes important technologies in silicate industry such as sintering, solid matter decomposition, transition modification, etc. Another chapter deals mineralogy, structure and properties of eminent silicate raw materials. Emphases is given to characterization of clay minerals and their utilising. The experimental part handle the analytic techniques used for investigation of thermal decompostion, dehydroxylation, crystalization of Al-Si spinel phase and sintering process of washed kaolin Sedlec Ia from the region Carlsbad (Czech Republic). Concluding chapter reports on results of experimental work.
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Development of anorthite ceramics
Toman, Boris ; Šveda,, Mikuláš (referee) ; Sokolář, Radomír (advisor)
When firing calcium ceramic materials creates a new crystalline phase anorthite. It can significantly improve the properties of ceramic body. This work deals with the possibilities of development anortitové ceramics using non-plastic raw materials, particularly alumina cement compared with conventional ceramics based on mullite.
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TiO2 pillared clay for photocatalytic purposes
Fiala, Michal ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
Bachelor’s thesis describes preparation of mixed catalytic systems kaolin/ TiO2 and metakaolin/ TiO2. Samples were prepared via hydrolysis of TiCl4 in kaolin suspension. Catalyst metakaolin/ TiO2 was prepared by calcination of this material under static oven atmosphere at 600 °C. Thermal analysis (simultaneous TG-DTA), infrared spectroscopy (FT-IR) and electron microscopy (REM) were used for samples characterization. Catalytic efficiency of mixture kaolin (Sedlec Ia) or metakaolin with TiO2 (anatase) was compared with pure kaolin. Experiment is based on oxidation of ethylalcohol, which was introduced in to reactor in flow of inert gas (argon). Amount of decomposed ethylalcohol is proportion to concentration of oxygen in gas product outputting from reactor. System kaolin/ TiO2 show higher catalytic performance than metakaolin/ TiO2 catalyst.
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