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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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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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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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