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Optimization of Working Mass Composition for Dense Silica Bricks Production.
Maňák, Jan ; Lang,, Karel (referee) ; Nevřivová, Lenka (advisor)
A silica bricks is a refractory material which is used mainly in coke industry, glass industry and metallurgy. This material constitute of the quartz modifications. Compact silica is an irreplaceable part of the coke battery and its compactness and robustness is important for quality and long endurance. Very important for large compactness is a grain curve of work matter. This thesis deals with influence of different grain of work matter.
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Technological Possibilities of Using Waste Claystone for Manufacturing Refractory Grog burned in blast furnaces
Konečný, Martin ; Tvrdík,, Lukáš (referee) ; Nevřivová, Lenka (advisor)
Aluminosilicate refractory grog are being manufactured by firing refractory clays, claystone and shale. Firing takes place mainly in rotary or blast furnaces. However, when adjusting the raw material before firing in blast furnaces, the formation of the fine clay particles takes place. It is not possible to fire the fine particles in blast furnaces the usual way, which leads to the generation of waste. There is a possibility, however, to form briquettes of these particles, which can be fired in blast furnaces. This solution also brings the possibility of adjusting the mixture by using correction raw materials or other types of clay. Using this method, it is possible to produce a special refractory grog with specific properties.
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Chemical Additives Effect on the Properties of Ceramic Mass.
Sarvaš, Ondřej ; Sokolář, Radomír (referee) ; Nevřivová, Lenka (advisor)
The bachelor’s thesis focuses on chemical additives used in the ceramic industry. There are described commonly used additives mainly in the fields of fine ceramic and special ceramic, as well as less utilized additives. The experimental part focuses on the influence of the additive BioKeram made by Borregaard for ceramic mass in the brick industry used for hollow clay blocks. A special focus is on the effect on rheological properties of the ceramic mass and a minor focus is on physical and mechanical properties of burned ceramic body.
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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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Mullite Refractory Grog
Zemánek, David ; Tvrdík,, Lukáš (referee) ; Nevřivová, Lenka (advisor)
Refractory aggregate manufactured from common clays, claystones and shales in Czech Republic are mostly classified as fireclay. For specific applications are these grogs not suitable and there is a need to use grogs with higher content of alumina oxide. Theoretical part of this thesis is focused on the mineral mullite, which is one of the basic minerals in Al2O3 - SiO2 system. Research is focused on methods of mullite production, manufacture of recfractory grog and new possibilities in modification of current raw materials. In experimental part is carried out a verification of possible production of grogs with increased alumina content according to the designed composition.
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Assessment of resistance castables to chemically aggressive environments.
Mátl, Daniel ; Henek,, Milan (referee) ; Nevřivová, Lenka (advisor)
There are applications of refractory concretes for places where these are exposed to corrosive environments. This bachelor thesis deals with both description the corrosive effects and methodology of their testing. One of the most important properties of materials, affecting the chemical corrosion resistance, is their density. The practical part of the thesis is focused on testing the grogs which are currently used for production of refractory concrete. The aggregates were tested for the resistance to sulfuric acid.
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The Effect of Thermal Exposure of the Porosity and Mineralogy of Dense Silica Bricks.
Janek, Ondřej ; Kotouček, Miroslav (referee) ; Nevřivová, Lenka (advisor)
Silica bricks is a refractory building material which contains at least 93 % of silicon dioxide in polymorphic forms, mostly -tridymite, -cristobalite and unreacted -quartz. In glass industry is used for building crowns of glass tanks and in coke industry is used for building coke oven batteries. The advantage is the high refractoriness under load, high resistance to acidic melts. The disadvantage is the low resistance to changes in temperature below 600 °C. The thesis deals with the influence of repeated firing on the silica bricks and to its porous structure and mineralogical composition.
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Monitoring the Influence of ceramic bond on the properties of insulating refractory materials
Friček, Jakub ; Kovář,, Pavel (referee) ; Nevřivová, Lenka (advisor)
Thermal insulating refractories are an integral part of each thermal unit since they reduce its energy consumption. The current phenomenon of saving in both environmental and financial aspects reflects in searching for such possibilities to produce at lower manufacturing and material costs. One of the possible ways is to valorise waste materials. The theoretical part then deals with the division of refractory materials, classification of thermal insulation refractory materials and manufacturing technologies. The experiment is focused on the production of insulating refractory materials made from plastic dough with a possibility of using sawdust and materials made by pressing mixture moist, with a focus on coal bottom ash. Both of these technologies will be tested for the possibility of modification by using mixed clays and of increasing the strength by using clays with lower sintering temperature.
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Diagnostic Methods Suitable for Monitoring of Drying Process of Brick Product
Sarvaš, Ondřej ; Sokolář, Radomír (referee) ; Nevřivová, Lenka (advisor)
This work deals with the study of diagnostic methods suitable for monitoring of the drying process of brick raw materials. Based on the extensive literature search, several parameters are selected, which are appropriate to monitoring during drying. In addition, a methodology for measuring these selected parameters is proposed. In the experimental part, the use of all described methods is gradually verified on the brick raw material with and without shortening additive (also known as grog). Was carried out: measurement of the surface temperature in the climatic chamber, determination of humidity distribution in the sample, determination of moisture diffusivity, determination of tensile strength, determination of ultrasonic wave velocity and determination of dynamic E-modulus of elasticity. Results of experiments and the gained experiences show, that at least two of the above-mentioned monitoring methods are very appropriate and beneficial – determination of moisture diffusivity and determination of tensile strength. In the work was described in detail the procedure of determination of moisture diffusivity of material. The dependence of moisture diffusivity on the moisture content of the dried material, has been described. Also, differences between raw material with grog and without grog has been described. As part of the practical verification of the experiment designed to determine the tensile strength at different humidity levels of test samples. A new shape of the test specimens and a new device were designed to allow them to be attached to a hydraulic press. The results of this work show that the tensile strength of the ceramic green bodies is primarily dependent on the moisture content of the material. The type of raw material almost does not affect the tensile strength.
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