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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vilka alternativ finns till deponering : En plockanalys av deponifraktion från återvinningscentral

Vollan Johansson, Cecilia January 2020 (has links)
Today, a large part of the recycling facilities inert waste goes to landfill.  Landfilling with waste leads to greenhouse gasemissions and the accumulation of pollutants that are liable to leak into the surrounding environment. Water and waste expertise in Norr AB (Vakin) is responsible for all waste management in the municipality of Umeå and Vindeln and aims to climb up the waste hierarchy by finding ways to recycle landfill waste. Today 100% of the landfill fraction is deposited. The purpose of the study is to investigate alternative treatment methods of waste in a landfill fraction, to reduce the amount of landfill waste. A sorting analysis was performed at Dåva landfill and waste facility in Umeå AB (Dåva DAC) to investigate the waste content in a landfill fraction. Interview questions were sent via e-mail to communal recycling centers to compare the handling and content of the required landfill fraction. The result show that landfill fraction contained hazardous waste, glass, porcelain, concrete, plasterboard/insulation, metal, combustible/plastic, brick, stone, tile/clinker and cardboard. To recycle construction and demolition waste, the fraction must be uniform and free of extraneous material The conclusion is that concrete, tile/clinker, brick and stone are sub-fractions that have the greatest potential for recycling. With a better waste sorting at the recycling facility, the amount of landfill fraction can be reduced.
12

Studium tvorby a kinetiky hydratace belitického slínku / Studying Formation and Kinetics of Belite Clinker Hydration

Halešová, Adéla January 2017 (has links)
DIPLOMA THESIS IS DEVOTED TO THE STUDY OF PREPARATION OF PURE BELITE CLINKER FOR THE POTENTIAL INCREASE OF KINETICS OF THE HYDRATION PROCESS BY CHEMICAL ACTIVATION. THE THESIS OF THIS WORK IS BASED ON RESEARCH FINDINGS CONCERNING BELITE CLINKER AND RESEARCH AT THE INSTITUTE OF THD. THE THESIS AIMS TO DESIGN COMPOSITION OF THE RAW MEAL BURNING BELITE, FOLLOWING MODIFICATION BY SULPHATE AND POTASSIUM CARBONATE IN ORDER TO POTENTIALLY INCREASE THE REACTIVITY OF THE BURNT BELITE CLINKER AND THE LABORATORY FIRING OF PREPARED SAMPLES. THE LAST STEP WAS TO ASSESS THE MINERALOGICAL COMPOSITION OF BURNED SAMPLES XRD ANALYSIS AND FOLLOWING COMPARISON CELL PARAMETER OF BELITE WITH AND WITHOUT ADDED MODIFYING ADDITIVES.
13

Influence des conditions thermo-hydriques de conservation sur l'hydratation de matériaux cimentaires à base d’une fine recyclée / Influence of the thermo-hygral conservation conditions on the hydration of recycled fine-based materials

Bordy, Arthur 13 December 2016 (has links)
La valorisation, comme granulats, des matériaux issus du recyclage du béton de démolition contribueà diminuer les surfaces dédiées au stockage des déchets et à limiter le recours systématique auxressources naturelles. L’emploi de fines recyclées à partir de béton de déconstruction s’inscrit danscette démarche et permet par ailleurs, quand la fine est utilisée en substitution partielle du cimentlors de la fabrication de nouveaux matériaux cimentaires, de réduire l’impact sur l’environnement deces matériaux.Cet usage conduit à mettre en présence dans la pâte à l’état frais du ciment anhydre et du cimenthydraté, ce qui pose la question de l’impact de cette situation sur le matériau. Pour y répondre enpartie, les travaux de recherche présentés dans cette thèse ont pour objectifs principaux d’étudier leprocessus d’hydratation d’une phase anhydre en présence d’autres phases hydratées, et d’analyserl’influence des conditions thermo-hydriques de conservation (HR et T°) sur les cinétiquesd’hydratation des matériaux cimentaires.Pour ce faire, une campagne expérimentale a été menée sur des mortiers et leurs pâtes de cimentéquivalentes fabriqués en remplaçant une partie de leur ciment Portland par une fine issue durecyclage d’une pâte de ciment durcie et bien hydratée. Un suivi au cours du temps des teneurs enPortlandite, de la porosité totale, de la résistance à la compression ainsi que de la résistance à lacarbonatation accélérée des matériaux a été réalisé. Les résultats obtenus montrent qu’il est possiblede fabriquer des mortiers en substituant le ciment par une fine obtenue uniquement par concassageet broyage d’une pâte de ciment durcie. Cependant, l’augmentation du taux de substitution massiquedu ciment par la fine recyclée s’accompagne d’une altération des propriétés et performances desmortiers. Les résultats du suivi d’hydratation couplés aux résultats d’analyse de la microstructure ontmontré que l’effet des conditions thermo-hydriques de conservation sur les cinétiques d’hydratationdes différentes pâtes de ciment dépend de leurs propriétés intrinsèques (microstructure). Celapourrait expliquer l’absence de consensus dans la littérature sur la valeur de l’humidité relativeambiante conduisant à l’arrêt de l’hydratation.En parallèle à l’étude expérimentale, une étude numérique de l’influence des conditions thermohydriquesde conservation sur l’hydratation des pâtes de ciment a été menée. Pour les besoins del’étude, une réadaptation du code de calcul utilisé, CEMHYD3D, a été nécessaire. Les résultatsobtenus montrent que, lors de l’hydratation, la Portlandite initialement présente dans le matériau(apportée par la fine recyclée) se dissout au contact de l’eau alors que la phase encore anhydre enproduit. Cette étude a également permis de conforter les résultats expérimentaux quant à l’influencede l’humidité relative ambiante sur l’hydratation. / The use, as aggregates, of recycled materials from demolished concrete contributes to limit landfill and the systematic use of natural resources. Using recycled fines from the deconstruction concrete is an extension of this approach. When used as a partial substitution for cement in cementitious materials, it may also be a solution to reduce the environmental impact of these materials.This specific use induces the presence of anhydrous cement particles and hydrated cement phases in the fresh material. This raises the question whether and how it can impact the hydration process. With the aim to answer, at least partially, to this question, the thesis presents a study of the hydration process of an anhydrous phase in the presence of other hydrated phases, and analyzes the influence of the conservation conditions (RH and T°) on the hydration kinetics of cementitious materials.An experimental campaign was conducted on mortars and their equivalent cement pastes designed by replacing a part of their Portland cement by a recycled cement paste fine. The monitoring of the Portlandite content, the total porosity, the compressive strength and the accelerated carbonation of the materials was achieved. The obtained results show that it is possible to design mortars by substituting their cement by a fine obtained only from crushing and grinding of a hardened cement paste. However, increasing the substitution ratio of the cement by the recycled fine was find to be accompanied by a deterioration of the mortars properties and performances. The results of the hydration monitoring coupled to investigations of the microstructure showed that the effect of conservation conditions on the hydration kinetics of the different cement pastes depends on their intrinsic properties (microstructure). This could explain the lack of consensus in the literature on the drying conditions under which hydration kinetics are strongly affected.In parallel to the experimental study, a numerical study of the influence of the conservation conditions on the hydration of cement pastes was conducted. Readjustments of the parameters of the used code (CEMHYD3D) were necessary. The obtained results show that, during hydration, the Portlandite originally present in the material (provided by the recycled fine) dissolves in contact with water, while the anhydrous phase produces new Portlandite. This study consolidated moreover the experimental results on the influence of the ambient relative humidity on hydration.
14

Modifikace vlastností portlandských cementů orientovaná na snížení emisí CO2 / Modicications of Portland cement properties focused on reducing CO2 emissions

Magrla, Radek January 2013 (has links)
This thesis aims to burn raw material with a lower content of carbonate component for the production of Portland cement. Substitution of carbonate component is done by fluidized fly ash. The model cements are tested of basic technological properties and the hydration process is observed.
15

Determinação de manganês em amostras de cimento e clínquer por voltametria de redissolução catódica empregando eletrodos de ouro / Manganese determination in cement and clinker samples by cathodic stripping voltammetry using gold electrodes

Joca, Jhonny Frank Sousa 22 June 2011 (has links)
Este trabalho apresenta o desenvolvimento e a aplicação de um método alternativo para determinação de manganês em amostras de cimento e clínquer por voltametria de redissolução catódica por onda quadrada empregando eletrodos de ouro. Após estudos exploratórios acerca do comportamento eletroquímico do manganês no eletrólito suporte H3BO3 0,20 mol L-1 / KCl 0,10 mol L-1 com pH 6,5 e a otimização dos parâmetros operacionais para a voltametria de onda quadrada, foram obtidos excelentes resultados na determinação de manganês nas amostras analisadas. Destacam-se a ótima linearidade, verificada em duas faixas distintas de concentração, e os baixos limites de detecção e quantificação obtidos (3,1 x 10-8 mol L-1 e 9,8 x 10-8 mol L-1, respectivamente), além da concordância entre os resultados obtidos pela técnica eletroanalítica quando comparados aos resultados fornecidos pela espectrometria de absorção atômica de chama (FAAS). Para o tratamento das amostras foi avaliada a eficiência da extração ácida assistida por ultrassom. Foram avaliados ácidos minerais individualmente (HCl, H2SO4 e HClO4 em diferentes concentrações), em mistura ou ainda associados a H2O2. Os melhores resultados foram obtidos utilizando uma solução de HCl 3 mol L-1, que extraiu quantitativamente o manganês nas amostras analisadas. Os resultados obtidos foram concordantes com a metodologia padrão utilizada para a abertura da amostra e posterior análise por espectrometria de absorção atômica de chama, que emprega o aquecimento em chapa e a mesma solução extratora. / This work describes the development and application of a new alternative method for determination of manganese in cement and clinker samples by square wave cathodic stripping voltammetry using gold electrodes. After exploratory studies on the electrochemical behavior of manganese in H3BO3 0.20 mol L-1 / KCl 0.10 mol L-1 supporting electrolyte at pH 6.5 and the optimization of operating parameters for the square wave voltammetry, excellent results were obtained for determination of manganese in the samples analyzed. Most notable are the excellent linearity, verified in two distinct concentration bands and the low limits of detection and quantification obtained (3,1 x 10-8 mol L-1 e 9,8 x 10-8 mol L-1, respectively), in addiction to the concordance between the obtained results by the electroanalytical technique when compared to the provided by the flame atomic absorption spectrometry. For samples treatment were tested the efficiency of the ultrasound-assisted extraction. Were evaluated individually mineral acids (HCl, H2SO4 and HClO4 at different concentrations) in a mixture or associated with H2O2. the best results were obtained using a 3 mol L-1 HCl solution, which extracted manganese quantitatively from the analysed samples, in comparison to the standard method for extraction, targeting a later atomic absorption flame spectrometry analysis, which uses the plate heating and the same extracting solution. The obtained results for the analysed samples agrees with the cement and clinker samples of the used literature
16

Optimisation de la formation d'espèces minérales soufrées en chambre de combustion lors de l'incinération de déchets dangeureux : cas du Mancozeb et d'un charbon actif soufré / Optimization of sulfur containing minerals' formation in incinerator furnace during thermal treatment of dangerous wastes : the cases of Mancozeb and a soiled activated carbon

Giroud, Nicolas 05 October 2011 (has links)
Le traitement thermique de déchets industriels dangereux à forte teneur en soufre peut engendrer des difficultés de conduite des installations d'incinération du fait des brusques variations de charges en soufre. Ce travail de thèse a pour objectif l'optimisation de la formation d'espèces minérales soufrées stables à haute température lors de l'incinération de déchets dangereux. Les mécanismes de décomposition thermique de deux déchets (le Mancozeb et un charbon actif soufré) sous air et sous azote ont dans un premier temps été élucidés en thermogravimétrie. La connaissance des espèces soufrées émises en fonction de la température lors de la décomposition thermique a permis la sélection de composés minéraux dits "piégeants" pour capter le soufre sous forme solide. Des modélisations thermodynamiques par minimisation de l'enthalpie libre du système ainsi que des essais en four à moufle ont pour cela été conduits. Les conditions de piégeage du soufre par la chaux ont par la suite été optimisées dans un four horizontal de laboratoire. Pour chacun des deux déchets, la formation et la conservation au cours du temps d'espèces réductrices au sein du lit de déchet permet de piéger le soufre sous forme de sulfure de calcium à 1100 °C sous air. Des essais dans un pilote de laboratoire équipé d'un four à grille ont permis de confirmer les résultats obtenus au laboratoire et ont produit suffisamment de résidus pour soumettre le mâchefer contenant les sulfures à des tests de lixiviation selon la norme NF-EN 12457-2. Ils révèlent que le mâchefer produit est admissible en centre de stockage de déchet ultime de classe 1 conformément à la réglementation en vigueur. / Thermal treatment of dangerous wastes with high sulfur contents may lead to difficulties in thermal treatment unit control because of strong variation in sulfur contents. This work aims at favoring the in-situ formation of high temperature stable minerals in which sulfur is trapped. Thermal decomposition mechanism of two dangerous wastes (Mancozeb and a soiled activated carbon) have been investigated under both air and nitrogen atmosphere through thermogravimetric analysis. Knowing the temperature of gaseous emissions and the speciation of emitted sulfur compounds, made it possible to simulate the reactivity of sulfur with several calcium based products using the Enthalpy minimization model. Tests were then performed in a horizontal laboratory furnace to optimize the formation of sulfur minerals from lime and wastes, at 1100°C under air atmosphere. The occurrence of reducing conditions in some parts of the load leads to the formation of calcium sulfide, stable provided the reducing conditions are kept locally. Upscale tests were then performed in a grid furnace and confirmed the obtained at laboratory scale : sulfur is trapped by lime in calcium sulfide only in default of oxygen. The obtained sulfide containing residues were submitted to standardized leaching test NF-EN 12457-2. These residues respect the prevailing regulations concerning its admission in dangerous ultimate wastes storage center.
17

Etude des modes d'action d'agents de mouture sur le broyage du clinker

Romilliat, Elodie 20 January 2006 (has links) (PDF)
Le broyage du clinker dans des tubes-broyeurs à boulets en acier est une étape très consommatrice d'énergie électrique dans la fabrication du ciment, et son rendement énergétique est très faible. Pour améliorer le rendement de cette opération, des produits appelés agents de mouture sont ajoutés en très faibles quantités au broyage du clinker. Cependant, les modes d'action de ces produits restent mal connus à l'heure actuelle. Dans le but de mieux connaître les mécanismes d'action de ces produits, deux agents de mouture sont étudiés sur le broyage du clinker. L'un d'entre eux, appelé « Mi », est utilisé couramment en industrie et est constitué d'un mélange d'eau et d'acétate de triéthanolamine. L'autre qui est noté « formulation F », se compose de trois molécules organiques. Ce dernier a un effet différent de celui de Mi sur le broyage du clinker en laboratoire, utilisant un broyeur de type planétaire. <br />Nous avons montré que ces deux produits agissent aussi favorablement sur le rendement du broyage d'autres minéraux tels que le calcaire et le laitier. Leur mode d'action n'est pas dépendant de la nature du milieu de broyage puisque Mi et F sont efficaces dans des bols de broyage en acier ou en alumine.<br />Leur mode d'action est lié à l'amélioration de la désagglomération de la poudre au cours du broyage grâce à un effet dispersant sur le clinker.
18

Contribution à l'utilisation de sous-produits industriels : application au cas du phosphogypse de Sfax ( Tunisie)

Rouis, Badreddine 10 July 1991 (has links) (PDF)
Le travail exposé dans ce mémoire est une approche pour la réutilisation d'un sous produit industriel: Le PHOSPHOGYPSE. Nous avons commencé par un rappel du cadre géo-politique de cette étude en précisant l'origine du matériau, son mode de stockage et son incidence sur l'environnement de la ville de SFAX (Tunisie). En deuxième partie, nous avons étudié la possibilité de l'utilisation du phosphogypse en remblai en effectuant une série d'essais géotechniques dont le paramètre principal est la teneur en eau. Nous avons placé cette étude dans le cadre climatique de la ville de SFAX. La troisième partie de ce travail est une étude préliminaire de la possibilité de la fabrication d'un clinker de ciment portland à partir de phosphogypse. Pour cela, nous avons effectué une série d'analyses pour déterminer les compositions, chimique et minéralogique, de ce matériau. Ceci nous a permis de proposer une composition corrigée d'un cru à base de phosphogypse qui tient compte de la présence des phosphates dans sa composition.
19

Improved cement quality and grinding efficiency by means of closed mill circuit modeling

Mejeoumov, Gleb Gennadievich 15 May 2009 (has links)
Grinding of clinker is the last and most energy-consuming stage of the cement manufacturing process, drawing on average 40% of the total energy required to produce one ton of cement. During this stage, the clinker particles are substantially reduced in size to generate a certain level of fineness as it has a direct influence on such performance characteristics of the final product as rate of hydration, water demand, strength development, and other. The grinding objectives tying together the energy and fineness requirements were formulated based on a review of the state of the art of clinker grinding and numerical simulation employing the Markov chain theory. The literature survey revealed that not only the specific surface of the final product, but also the shape of its particle size distribution (PSD) is responsible for the cement performance characteristics. While it is feasible to engineer the desired PSD in the laboratory, the process-specific recommendations on how to generate the desired PSD in the industrial mill are not available. Based on a population balance principle and stochastic representation of the particle movement within the grinding system, the Markov chain model for the circuit consisting of a tube ball mill and a high efficiency separator was introduced through the matrices of grinding and classification. The grinding matrix was calculated using the selection and breakage functions, whereas the classification matrix was defined from the Tromp curve of the separator. The results of field experiments carried out at a pilot cement plant were used to identify the model's parameters. The retrospective process data pertaining to the operation of the pilot grinding circuit was employed to validate the model and define the process constraints. Through numerical simulation, the relationships between the controlled (fresh feed rate; separator cut size) and observed (fineness characteristics of cement; production rate; specific energy consumption) parameters of the circuit were defined. The analysis of the simulation results allowed formulation of the process control procedures with the objectives of decreasing the specific energy consumption of the mill, maintaining the targeted specific surface area of the final product, and governing the shape of its PSD.
20

Size-by-size Analysis Of Breakage Parameters Of Cement Clinker Feed And Product Samples Of An Industrial Roller Press

Camalan, Mahmut 01 August 2012 (has links) (PDF)
The main objective in this study is to compare breakage parameters of narrow size fractions of cement clinker taken from the product end and feed end of industrial-scale high pressure grinding rolls (HPGR) in order to assess whether the breakage parameters of clinker broken in HPGR are improved or not. For this purpose, drop weight tests were applied to six narrow size fractions above 3.35 mm, and batch grinding tests were applied to three narrow size fractions below 3.35 mm. It was found that the breakage probabilities of coarse sizes and breakage rates in fine sizes were higher in the HPGR product. This indicated that clinker broken by HPGR contained weaker particles due to cracks and damage imparted. However, no significant weakening was observed for the -19.0+12.7 mm HPGR product. Although HPGR product was found to be weaker than HPGR feed, fragment size distribution of HPGR product did not seem to be finer than that of the HPGR feed at a given loading condition in either the drop weight test or batch grinding test. Also, drop weight tests on HPGR product and HPGR feed showed that the breakage distribution functions of coarse sizes depended on particle size and impact energy (J). Batch grinding tests showed that the specific breakage rates of HPGR product and HPGR feed were non-linear which could be represented with a fast initial breakage rate and a subsequent slow breakage rate. The fast breakage rates of each size fraction of HPGR product were higher than HPGR feed due to cracks induced in clinker by HPGR. However, subsequent slow breakage rates of HPGR product were close to those of HPGR feed due to elimination of cracks and disappearance of weaker particles. Besides, the variation in breakage rates of HPGR product and HPGR feed with ball size and particle size also showed an abnormal breakage zone where ball sizes were insufficient to effectively fracture the coarse particles. Breakage distribution functions of fine sizes of HPGR product and HPGR feed were non-normalizable and depended on particle size to be ground. However, batch grinding of -2.36+1.7 mm and -1.7+1.18 mm HPGR feed yielded the same breakage pattern.

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