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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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Information system in the maintenance
Lang, Karel ; Hammer, Miloš (referee) ; Řezníčková, Hana (advisor)
The aim of this bachelor thesis is to investigate the possibilities of usage various information systems in the management of company maintenance and to apply this knowledge to the current management maintenance system in Megatech Industries Hlinsko. The first part of the problem was solved by mapping the current market and comparing the offers of the individual information system maintenance providers, the second one was carried out in cooperation with the maintenance manager of Megatech Industries Hlinsko using the software solution Palstat CAQ. The findings of this work show that enterprise maintenance management can be performed in many ways, and almost any maintenance system can be supported by some kind of software support. Meanwhile, it has been proven, on the example of Megatech Industries Hlinsko, that no way of managing maintenance is perfect, and an independent observer can always find reserves for improvement.
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New Possibilities to Reduce Raw Material Costs in the Cordierite Production
Sopko, Marek ; Lang, Karel (referee) ; Nevřivová, Lenka (advisor)
The diploma thesis focuses on new possibilities to reduce raw materials costs in production of heat-resistant cordierite ceramics. Cordierite is very often used as furnace wagon lining and for production of blazing utilities for its high resistance against temperature changes. The thesis gives complete overview of cordierite material. It includes description of different production technologies for form-pieces preparation, raw materials for their production and their applications. The goal of performed laboratory measuring in an experimental part was to verify and prove a possibility of reducing raw-material costs in production of cordierite ceramics by using cheaper preferably secondary raw materials.
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Application of metakaolin in refractory materials
Tvrdík, Lukáš ; Rovnaníková, Pavla (referee) ; Havlica,, Jaromír (referee) ; Kutzendőrfer,, Jaroslav (referee) ; Lang, Karel (advisor)
Refractory materials are irreplaceable in all industrial fields where it is necessary to use high temperatures. This paper deals with the use of metakaolin in refractory materials that allows the operation of such facilities. In recent decades has the development made significant progress in quality parametres, which extended life period of refractory materials in their use and significantly decreased the specific consumption of refractory materials in various technologies. This phenomenon is also called "harakiri effect". At the same time a constant pressure to the lowest prices of products is on the refractory market. Metakaolin seems to be appropriate raw material, which may help to achieve interesting qualitative effects. It may affect many properties of the influence on the behavior of materials during processing, through physico-mechanical parameters and dipping to the economic efficiency of production.
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Phosphate Binders in Refractory Application
Švec, Jiří ; Drábik, Milan (referee) ; Lang, Karel (referee) ; Havlica, Jaromír (advisor)
The doctoral thesis is focused on the study, research and development of refractories with phosphate bonding. Primary motivation is preparation of phosphate-based binders that can be applied for non-shaped insulating material fabricated by “in situ” foaming. The phosphate binders based on Al2O3-H3PO4 system are one of the most common in refractory technology. The amphoteric nature of the aluminium and its oxides require the setting of Al2O3-H3PO4 binders under the higher temperatures. Application of higher temperatures is necessary to obtain the minimal manipulation strength of as-prepared green bodies. The main goal of the work is preparation of ytrium phosphate-based binders via different preparation techniques. Yttrium based binders would allow phosphate refractory preparation by standard way, i.e via reaction between binder and reactive aggregate, without structural disintegration of foamed material even before getting manipulation strength or the final firing procedure. Yttrium is more basic than aluminium and therefore more reactive in Y2O3-H3PO4 system.. Yttrium oxide is highly refractory material and sintered yttrium monophosphate has excellent properties from the thermal and corrosive stability point of view. This fact should compensate higher price of this material. Experimental part of this work studies the possibilities of binders preparation in Y2O3-H3PO4 system. The mixtures were designed to prepare binding phase Y(H2PO4)3. Products of these reactions were characterized in phase and chemical point of view. In order to study and describe setting and hardening processes of phosphate binders, the products were “in situ” analyzed by the thermal analyses and high-temperature diffraction analysis up to the 1300 °C. High temperature products were then characterized by means of phase and chemical composition and morphology.
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Refractory Products for Aluminum Metallurgy Industry
Kupcová, Zuzana ; Lang, Karel (referee) ; Nevřivová, Lenka (advisor)
The master´s thesis focuses on high-alumina refractory materials used mainly in aluminia metallurgy. Teoretical part of this thesis is aimed at distribution of refractory materials, possibilities of its production and raw material basis. Characteristic properties are described as well as application possibilities in aluminium technology. In final part of this thesis experimental data are evaluated to obtain physical, mechanical, chemical properties of high-alumina refractory materials. Those are used for economical optimalization of raw materials.
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Phosphate bond of foam filters and its influence on the technical properties
Langer, Jan ; Lang, Karel (referee) ; Sokolář, Radomír (advisor)
The theses deals with the preparation of phosphate binder. This binder provides not only high strength, but also high-heat resistance. The bond is made of acid phosphate and alumina. There should be substitute of alumina (Cr2O3) or the adition of its. The slurry was prepared according to the applicable procedures of Pyrotek. After this, the slurry was applied to the polyurethane foam, dried and kilned. The result is foam filter for aluminium casting.
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Application of metakaolin in refractory materials
Tvrdík, Lukáš ; Rovnaníková, Pavla (referee) ; Havlica,, Jaromír (referee) ; Kutzendőrfer,, Jaroslav (referee) ; Lang, Karel (advisor)
Refractory materials are irreplaceable in all industrial fields where it is necessary to use high temperatures. This paper deals with the use of metakaolin in refractory materials that allows the operation of such facilities. In recent decades has the development made significant progress in quality parametres, which extended life period of refractory materials in their use and significantly decreased the specific consumption of refractory materials in various technologies. This phenomenon is also called "harakiri effect". At the same time a constant pressure to the lowest prices of products is on the refractory market. Metakaolin seems to be appropriate raw material, which may help to achieve interesting qualitative effects. It may affect many properties of the influence on the behavior of materials during processing, through physico-mechanical parameters and dipping to the economic efficiency of production.
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Information system in the maintenance
Lang, Karel ; Hammer, Miloš (referee) ; Řezníčková, Hana (advisor)
The aim of this bachelor thesis is to investigate the possibilities of usage various information systems in the management of company maintenance and to apply this knowledge to the current management maintenance system in Megatech Industries Hlinsko. The first part of the problem was solved by mapping the current market and comparing the offers of the individual information system maintenance providers, the second one was carried out in cooperation with the maintenance manager of Megatech Industries Hlinsko using the software solution Palstat CAQ. The findings of this work show that enterprise maintenance management can be performed in many ways, and almost any maintenance system can be supported by some kind of software support. Meanwhile, it has been proven, on the example of Megatech Industries Hlinsko, that no way of managing maintenance is perfect, and an independent observer can always find reserves for improvement.
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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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