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Milling activators use in the very fine powder material practice.
Spurný, Marek ; Kejík, Pavel (referee) ; Svěrák, Tomáš (advisor)
This work deals kinetics of grinding Portland cement clinker which is influenced by addition of grinding inlays surfactants. In an experiment, attritor-type stirred mill was used and surface active grinding additives such as polyethylenglykol (PEG), triethylamin (TEA) and acetate of ammonium were utilized. Granulometric distribution graph obtained from laser diffraction analysis provides data for plotting development diagrams for milling process.
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Specification of the phase composition of Portland clinker
Vávrová, Alžběta ; Dlabajová, Lucie (referee) ; Másilko, Jiří (advisor)
This bachelor thesis deals with the determination of the phase composition of portland clinker and its optimization. The X-ray fluorescence spectroscopy, X-ray diffraction analysis and optical microscopy were used to solve this task. In the experimental section, X-ray fluorescence spectrometry results were used to calculate the potential phase composition of the clinker using the Bogue method. Then the X-ray diffraction analysis followed, it was used not only to determine the phase composition but also to determine amorphous content in the clinker. The microscope integration method was used to study the samples using optical microscopy. The obtained results were compared with each other and the main deficiencies of the individual methods were identified.
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Hybrid binders containing Portland clinker
Kratochvilová, Lucie ; Hrubý, Petr (referee) ; Opravil, Tomáš (advisor)
This bachelor thesis is focused on the use of cement kiln dust in combination with portland clinker. Cement kiln dust is a fine bulk material which is not good to mix further with cement, due to its unsuitable chemical composition. The aim of the bachelor thesis is to verify the possibilities of using this secondary material as a potential component of hybrid binders. For experimental part were taken several cement kiln dusts from different sources. The evaluation of the prepared binders was similar to Portland cement, the tests were performed according to ČSN EN 196.
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Supersulphates cements
Mohelská, Lucie ; Wirthová, Michaela (referee) ; Opravil, Tomáš (advisor)
The work is studying posibilities of use secondary materials produced by energetical industry. In fact it studies posibilities of preparing supersulphates cements with secondary raw materials. Its main system for simulation was used milled portland clinker. To clinker were added diferent secondary raw materials from energetical industry with sulphate. On prepared samples were watched mechanical properties in time. Tested were different samples of secondary raw materials.
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The Role of Ferrous Sulphate as a Setting Regulator and a Portland Clinker Reduction Agent
Mončeková, Miroslava ; Rovnaníková, Pavla (referee) ; Drábik, Milan (referee) ; Havlica, Jaromír (advisor)
In 2003, the European Community Obligation (directive 2003/5C/EC) regulates a maximal value of soluble hexavalent chromium to 0.0002 % (per weight of dry cement). This limitation leads to modifications of the regular Portland cement by using of suitable reduction agents. Therefore, the possibilities of chromium reduction become a very actual topic. The primary goal of this work is a basic research of the ferrous sulphate influence on hexavalent chromium reduction and also its influence on Portland clinker hydration process. The reduction ability was determined by UV/VIS method. The mechanism and ferrous sulphate influence on Portland clinker hydration process was observed by isothermal calorimetry and mechanical strength tests. XRD method, SEM-EDS analysis and Raman microscopy were used for identification of formed hydration products. Study of hydration mechanism occurring in this system was focused on the divergence observations from the regular Portland cement hydration. Pore solution analysis provided significant information about chromium behavior during the hydration process (substitution and releasing). Chromium incorporation into structure of hydration products during the reduction process was also studied in the pure tricalciumaluminate system with targeted Cr6+ content. This work suggests the possible substitution of the trivalent and hexavalent chromium into structure of monosulphate (AFm) phase.
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Possibilities of utilization of solid residues from fluidized bed combustion for preparation of composite Portland cements
Beranová, Denisa ; Šiler, Pavel (referee) ; Opravil, Tomáš (advisor)
The bachelor thesis deals with possibilities of utilization of solid residues from fluidized bed combustion of coal, bed and filter ash, to be used in the production of composite Portland cements. 6 ash types were investigated, of which 3 were bed ash (finely ground) and 3 were filter ash colected from Ledvice, Tisová and Poříčí K8 power plants. The chemical composition of the ash collected was determined and the progress of a hydration reaction monitored, and then samples mixed with Portland clinker were prepared. Their respective compressive strength and flexural strength were then analysed and observations made on the hydration and composition of products of the hydration reaction. Finally the results of selected mixtures were verified with prepared standardized mortars.
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The influence of barium and its compounds on the formation and properties of Portland clinker
Zezulová, Anežka ; Rovnaníková, Pavla (referee) ; Palou, Martin (referee) ; Ptáček, Petr (advisor)
The work deals with the study of barium cement. Barium cements are used to prepare concrete that protects against ionizing radiation. Barium can be also present in a conventional Portland cement clinker as an impurity from alternative fuels or raw materials, which are increasingly used for clinker production, and thus change the structure and properties of the product. Various methods of preparation of this cement were studied in this work. Barium cements were prepared from raw meals of different composition, but always with the same procedure and burning temperature. Using suitable analytical methods, the work describes the influence of individual admixtures of raw meal on the phase composition of the resulting clinker. Furthermore, the work deals with monitoring the form and location of barium in the prepared clinker. Several experiments are focused on the study of hydration of prepared barium clinkers, the phase transformation is monitored by XRD and supplemented by analyses of hydration products. In this way, it was possible to obtain the data needed to describe the preparation, burning, and hydration of barium cements with different compositions. The work also deals in detail with the real use of barium cements. The ability of pastes and mortars from prepared barium cements to shield various types of ionizing radiation was tested and described experimentally. The results are presented in comparison with reference samples, which were prepared from commonly used Portland cement.
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Possibilities of hexavalent chromium reduction within portland cement hydration
Mončeková, Miroslava ; Koplík, Jan (referee) ; Šoukal, František (advisor)
The issue of Hexavalent chromium toxicity to Portland cement hydration is a very actual these days. It takes much effort to obtain a cement containing Cr(VI) less than 2 ppm. The primary objective of this diploma theses is to find appropriate reducing substances and specify their efficiency, as well as to make an attempt to optimize their dosage. As reducing substances there were plumbed sulphites and tin(II) salts. The influence of reducing substances applied to the hydration and cement properties were validated by strenght tests, the calorimetric measurement and the volume-variation measurement. And also the changes in hydration products microstructure of Portland clinker after the gypsum replacement by sulphite ions were plumbed. The study of microstructure is based on SEM and XRD methods.
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Study of Phase Changes During Portland Clinker Firing
Pertlová, Alena ; Fridrichová, Marcela (referee) ; Gazdič, Dominik (advisor)
The presented bachelor thesis deals with monitoring of transformations during the burning of cement clinker. The theoretical part is devoted to the theories regarding the burning of Portland clinker and to the description of clinkers properties in general. The focus is put on the modern low-energy clinkers as well. Moreover, the thesis deals with several methods for determining the phase composition of cement clinker including HT-XRD analysis, which allows to monitor the behaviour of individual phases at high temperatures besides the determination of the phase composition. In the experimental part, there is introduced the project proposal of the model raw mixture used to produce ordinary Portland clinker and raw mixture of low-energy ternesite clinker. Furthermore, the thesis shows HT-XRD analysis done in the high temperature chamber, followed by the evaluation of results and their comparison with the theoretical background.
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