Cette étude a pour objectif d’élaborer des mousses de géopolymère à macroporosité connectée pour le traitement des effluents liquides radioactifs. La première partie de ce travail a consisté à synthétiser des monolithes de géopolymères par moussage direct en utilisant le peroxyde d’hydrogène (H2O2) comme agent porogène. Celui-ci se décompose en milieu basique pour produire de l’oxygène et ainsi produire la mousse de géopolymère par nucléation/croissance de bulles d’oxygène jusqu’à épuisement du terme source et/ou prise du matériau. Pour stabiliser les bulles de gaz générées, l’ajout d’un tensioactif est nécessaire pour limiter les phénomènes de coalescence. L’influence de la concentration en H2O2, de la nature chimique du tensioactif et de la viscosité de la pâte sur la cinétique de production et sur les propriétés finales de la mousse ainsi produite a été étudiée. Les résultats montrent classiquement qu’une forte concentration initiale de H2O2 produit des mousses de forte porosité, avec des tailles de pores élevées et des propriétés mécaniques moindres. Par contre, le choix de la nature chimique du tensioactif a une très forte influence d’une part de la rhéologie de la pâte de géopolymère et d’autre part sur les propriétés du réseau poreux. En effet, par un choix approprié du tensioactif, il est possible d’obtenir des mousses de géopolymères à macroporosité fermée ou ouverte, avec des distributions en taille de pores plus ou moins étalées et de bonnes propriétés mécaniques. A l’issue de cette première étape, un monolithe de géopolymère à porosité ouverte a été fonctionnalisé par précipitation des particules d’hexacyanoferrate de cuivre connues pour être très sélectives vis-à-vis du césium. Les essais ont été réalisés en mode batch dans différents milieux (eau pure, eau douce et eau douce chargée de cations compétiteurs de charge en concentration importante). Les cinétiques et les isothermes d’adsorption du césium ont été déterminées sur une large gamme de concentration en césium (de l’état de trace jusqu’à 1000 ppm) et la mousse de géopolymère fonctionnalisée a montré des performances remarquables pour le piégeage sélectif du césium par rapport à une mousse non fonctionnalisée. En effet, les essais en milieu radioactif (trace de césium dans l’eau douce) ont montré que la valeur du coefficient de distribution (Kd) pour la mousse fonctionnalisée est de l’ordre 5.5 105 ml.g-1. / This study aims to develop geopolymer foams with connected macroporosity for the treatment of radioactive liquid wastes. The first part of this work was to synthesize geopolymer monoliths by direct foaming using hydrogen peroxide (H2O2) as blowing agent. It decomposes in a basic medium to produce oxygen and thus produces the geopolymer foam by nucleation and growth of oxygen bubbles until exhaustion of the source term and/or setting of the material. To stabilize the generated gas bubbles, the addition of a surfactant is necessary to limit coalescence phenomena. The influence of the H2O2 concentration, the chemical nature of the surfactant and the viscosity of the paste on the kinetics of production and on the final properties of the foam thus produced, was studied. The results conventionally show that a high initial concentration of H2O2 produces high porous foams, with high pore sizes and less mechanical properties. On the other hand, the choice of the chemical nature of the surfactant has a very strong influence on the one hand on the rheology of the geopolymer paste and on the other hand on the properties of the porous network. Indeed, by an appropriate choice of the surfactant, it is possible to obtain geopolymer foams with closed or open macroporosity, with pore size distributions more or less spread and with good mechanical properties. At the end of this first step, a well-connected geopolymer monolith was functionalized by precipitation of copper hexacyanoferrate particles known to be very selective with respect to cesium. The tests were performed in batch mode in different media (pure water, fresh water and fresh water loaded with competitor cations in high concentration). The kinetic and adsorption isotherms of cesium were determined over a wide range of cesium concentration (from trace to 1000 ppm) and the functionalized geopolymer foam showed remarkable performance for selective entrapment of cesium as compared to an unfunctionalized foam. Indeed, the tests in radioactive medium (trace of cesium in fresh water) have shown that the value of the distribution coefficient (Kd) for the functionalized foam is around 5.5 105 ml.g-1.

Made available in DSpace on 2014-12-17T14:07:05Z (GMT). No. of bitstreams: 1 DiegoBR_DISSERT.pdf: 2561284 bytes, checksum: 728dce6008fc70c37faa4759ea2eba6d (MD5) Previous issue date: 2012-02-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Nowadays, the search for new technologies that are able to follow the upcoming challenges in oil industry is a constant. Always trying properties improvements of the used materials, looking for the best performance and greater life time. Besides the search for technologies that show an improvement of performance, the search for materials environmentally correct along the whole production process. In Oil well cementing, this search for new technologies passes through the development of slurry systems that support these requests and that are also environmentally friendly. In this context, the use of geopolymer slurries is a great alternative route to cementing oil wells. Besides having good properties, comparable to Portland cement slurries, this alternative material releases much less CO2 gas in the production of their root materials when compared the production of Portland cement, which releases tons of CO2. In order to improve the properties of geopolymer slurries has been added Calcium Oxide, as observed in other studies that slurries where the Calcium is present the values of compressive strength is greater. The addition has been realized based in the CaO/SiO2 molar ratio of 0.05, 0.10 and 0.15. Have been performed compressive strength tests, thickening time, rheology and fliud loss control test of the slurries, following NBR 9831, as well as the physical chemical characterization of XRD, SEM and TG. Has been observed in most of the tests the slurries follow a tendency until the ratio of 0.10, which inverses in the ratio 0.15. This behavior can be explained by two phenomena that occur simultaneously, the first one is the break of the polymer chains and a consequent increase in molucules mobility, which prevails until the ratio of 0.1, and the second is possible approach of the chains due to the capacity of the calcium ions stabilize the charges of two different aluminum. There is only one linearity in the mechanical behavior that can be attributed to the appereance of the C-S-H phase. Based on this, it is concluded that the phenomenon of breaking the polymer chains predominates until the ratio of 0.1, causing an increase of the filtrate volume, lower rheological parameters and increasing thickening time. From the ratio of 0.15 the approach of the chains predominates, and the behavior is reversed / Nos dias atuais a busca por novas tecnologias que possam acompanhar os desafios que surgem dia a dia na ind?stria do petr?leo ? constante, sempre tentando melhorar as propriedades dos materiais que s?o utilizados, buscando o melhor desempenho e maior vida ?til. Al?m de buscar novas tecnologias ? de fundamental import?ncia o desempenho dos materiais e que estes sejam ambientalmente corretos. No ramo da cimenta??o de po?os de petr?leo, essa procura por novas tecnologias passa pelo desenvolvimento de sistemas de pastas que suportem as solicita??es requeridas pelas normas internacionais e nacionais para esse setor. Nesse contexto, lan?a o desafio de se produzir novos sistemas de pastas para o revestimento de po?os petrol?feros, sejam eles para po?os on shore ou off shore. As pastas geopolim?ricas apresentam-se como uma boa alternativa para a cimenta??o de po?os de petr?leo, pois alem de possuir boas propriedades, compar?veis as pastas de cimento Portland, esse material libera muito menos CO2 na produ??o das suas meterias primas quando comparados ? produ??o do cimento Portland. Com o intu?do de melhorar as propriedades das pastas geopolim?ricas foi adicionado o ?xido de c?lcio, pois foi observado em outros trabalhos que pastas onde o c?lcio esta presente os valores de resist?ncia a compress?o s?o maiores. A adi??o foi realizada baseada na raz?o molar CaO/SiO2 de 0,05, 0,10 e 0,15, foram realizados ensaios de resist?ncia a compress?o, tempo de espessamento, reologia e filtrado das pastas seguindo a NBR 9831, bem como as caracteriza??es f?sico qu?micas de DRX, MEV, TG. Foi observado que na maioria dos ensaios as pastas seguem uma tend?ncia ate a raz?o de 0,10 que se inverte na raz?o de 0,15. Esse comportamento pode ser explicado por dois fen?menos que ocorrem simultaneamente: o primeiro ? a quebra das cadeias polim?ricas com um conseq?ente aumento da mobilidade das mol?culas, que prevalece ate a raz?o de 0,1, e o segundo ? a poss?vel aproxima??o das cadeias devido a capacidade do ?on c?lcio estabilizar as cargas de dois alum?nios diferentes. Existe apenas a linearidade no comportamento mec?nico que pode ser atribu?do ao aparecimento da fase C-S-H. Com base nisso pode se concluir que o fen?meno de quebra das cadeias polim?ricas predomina at? a raz?o de 0,1, provocando o aumento no volume de filtrado, diminui??o dos par?metros reol?gicos e aumento do tempo de espessamento. A partir da raz?o 0,15 a aproxima??o das cadeias predomina e assim o comportamento se inverte

Made available in DSpace on 2014-12-17T14:07:08Z (GMT). No. of bitstreams: 1 EricaNMGP_TESE.pdf: 149123 bytes, checksum: d13a2a775b94d69d52d9e403106d2117 (MD5) Previous issue date: 2011-06-01 / The development of activities the of oil and gas sector have promoted the search for suitable materials for cementing oil wells. In the state of the Rio Grande do Norte, the integrity of the cement sheath tends to be impaired during steam injection, a procedure necessary to increase oil recovery in reservoirs with low-viscosity oil. The geopolymer is a material that can be used as alternative cement, since it has been used in the production of fire-resistant components, building structures, and for the control of toxic or radioactive residues. Geopolymers result from condensation polymer alkali aluminosilicates and silicates resulting three-dimensional polymeric structures. They are produced in a manner different from that of Portland cement, which is made an activating solution that is mixed with geopolymer precursor. Among the few works studied allowed us to conclude that the pastes prepared with metakaolin as precursor showed better performance of its properties. Several studies show the addition of waste clay as a means of reducing cost and improving end of the folder properties. On this basis, the goal is to study the influence of the addition of ceramic waste in geopolymer paste. To develop the study of rheology tests were carried out, filtered, thickening time, compressive strength, free water, specific gravity and permeability, according to the American Pretoleum Institute (API). The results for all formulations studied show that the folders have high mechanical strength to a light paste; low filtrate volume, absence of free water, very low permeability, slurry, consistent with a light paste, and thickening time low that can be corrected with the use of a retardant handle. For morphological characterization, microstructural, physical, chemical and thermal tests were carried out by XRD, MEV, DTA, TG, FTIR. In the trial of XRD, it was found that geopolymer is an amorphous material, with a peak of crystalline kaolinite. In tests of TG / DTA, revealed the presence of a significant event, which represents the mass loss related to water, and also observed the reduction of weight loss by increasing the concentration of ceramic waste. In the trial of MEV, we found a uniform matrix without the presence of other phases. In the trial of FT-IR, we observed the presence of the band related to water. From all results it was determined that the optimum concentration range of use is between 2.5 and 5% of waste ceramic / O desenvolvimento das atividades do setor de petr?leo e g?s tem promovido a busca de materiais mais adequados para cimenta??o de po?os de petr?leo. No estado do RN, a integridade da bainha cimentante tende a ser prejudicada durante a inje??o de vapor, procedimento necess?rio para aumentar a recupera??o do petr?leo em reservat?rios com ?leo de alta viscosidade. O geopol?mero ? um material que pode ser utilizado como cimento alternativo, uma vez que vem sendo empregado na produ??o de componentes resistentes ao fogo, na constru??o de estruturas, e para o controle de res?duos t?xicos ou radioativos. Geopol?meros resultam da condensa??o polim?rica de aluminosilicatos e silicatos alcalinos originando estruturas polim?ricas tridimensionais. S?o produzidos de uma maneira distinta daquela do cimento Portland, onde ? feita uma solu??o ativadora que ? misturada ao precurssor geopolim?rico. Dentre os trabalhos estudados, alguns permitiram-nos concluir que as pastas preparadas com metacaulim como precursor apresentaram melhor desempenho de suas propriedades. V?rios estudos apresentam a adi??o de res?duos argilosos como forma de redu??o do custo final e melhoria das propriedades da pasta. Com base nisso, o objetivo do trabalho ? estudar a influ?ncia da adi??o de rejeito cer?mico em pastas geopolim?ricas. Para o desenvolvimento do estudo foram realizados testes de reologia, filtrado, tempo de espessamento, resist?ncia ? compress?o, ?gua livre, peso espec?fico e permeabilidade, de acordo com o American Pretoleum Institute (API). Os resultados encontrados para todas as formula??es demonstram que as pastas estudadas apresentam resist?ncia mec?nica elevada para uma pasta leve; volume de filtrado baixo; aus?ncia de ?gua livre; permeabilidade muito baixa; pasta flu?da, coerente com uma pasta leve; e tempo de espessamento baixo, que pode ser corrigido com a utiliza??o de um retardador de pega. Para caracteriza??o morfol?gica, microestrutural, f?sico-qu?mica, qu?mica e t?rmica, foram realizadas caracteriza??es por DRX, MEV, DTA, TG, FT-IR. No ensaio de DRX, verificou-se que o geopol?mero ? um material amorfo, com um pico cristalino de caulinita. Nos testes de TG/DTA, foi observado a presen?a de um evento significativo, que representa a perda de massa referente a ?gua, sendo observado tamb?m a redu??o da perda de massa com o aumento da concentra??o de rejeito cer?mico. No ensaio de MEV, encontrou-se uma matriz uniforme e nos espectros de FT-IR, observou-se a presen?a da banda referente ? ?gua. A partir de todos os resultados foi poss?vel determinar que a faixa de concentra??o ?tima de rejeito cer?mico para uso em pastas geopolim?ricas ? entre 2,5 e 5 %

Les Technosols comprennent les sols soumis à une forte pression anthropique et en particulier les sols influencés par les matériaux d'origine humaine. Dans ce contexte, les sites miniers abandonnés peuvent souvent contenir une grande quantité de déchets transformés enrichis en métaux et métalloïdes. En comparaison avec les sols naturels, la singularité des Technosols miniers correspond à leur matériel parental constitués de déchets minéraux de granulométrie fine. Contrairement à leurs homologues peu anthropisés, les Technosols sont encore assez mal connus. L'objectif global de cette étude est d'approfondir les connaissances des processus pédogénétiques des Technosols développés naturellement à partir de déchets miniers de façon à mieux anticiper la réhabilitation de ces sites. Ainsi, différents profils ont été échantillonnés correspondant respectivement à d’anciennes exploitations de W, Pb-Ag, Sn et Au. Leurs fonctionnements pédologiques ont dès lors été étudiés afin de déterminer les liens potentiels et les leviers guidant leur évolution. Cette étude préliminaire correspond à une image contemporaine de ce que peut donner une réhabilitation naturelle (par simple formation de solum après végétation spontanée) pour une durée d’environ 75 ans en moyenne. Dans un second temps plusieurs techniques de réhabilitation ont été étudiés respectivement: (i) la phytoremédiation par culture du Douglas ainsi que (ii) la revalorisation des déchets par synthèse de géopolymères enrichis en déchets miniers. / The Technosols include soils subject to strong anthropogenic pressure and particularly to the soil influenced by human-made materials. In this context, abandoned mine sites can contain a large amount of transformed waste materials often enriched with metals and metalloïds. Compared to natural soils, the singularity of mining Technosols naturally developed from mining waste corresponding to their parental material made by fine-grained mineral waste. Unlike their poorly anthropized homologous, Technosols are not enough well known. So, the overall objective of this study is to increase knowledge of soil processes of Technosols after spontaneous vegetation impact. Thus, different profiles were sampled respectively corresponding to different abandoned mine exploitation type: W, Pb-Ag, Sn and Au. Their pedogenic way have therefore been studied to determine potential linkages and levers guiding their evolution. This preliminary study is based on the contemporary picture of a natural rehabilitation (by simple solum formation) for a period of about 75 years on average. Secondly several rehabilitation techniques have been studied respectively: (i) the phytoremediation by growing Douglas plant and (ii) the reused of waste by mine sediment based geopolymer synthesis.

Cement-based concrete is one of the main construction materials that is widely used for many construction applications due to its strength, durability, reflectivity, and versatility. However, it is acknowledged that production of cement as a primary material of concrete releases 1.8 Gt carbon dioxide (CO2) into the environment. It is estimated that one ton of cement production releases one ton of CO2 to the atmosphere. That is why, this work aims to create a concrete that could be an alternative to cement-based concrete. Geopolymer concrete (GPC) is an eco-friendly construction material and an alternative to conventional concrete that is produced by reacting aluminate and silicate bearing constituents with a caustic activator (i.e. sodium-based or potassium-based). Both potassium and sodium have been considered as generally safe intergradient by the FDA, based upon the observance of several good manufacturing practice conditions of use. Theses activators are used in various application including concrete, food, as a stabilizer, and as a thickening agent. Moreover, these activators are also used in making soap, as an electrolyte in alkaline batteries and in electroplating, lithography, and paint and varnish removers. Medically, these activators are widely used in the wet mount preparation of various clinical specimens for microscopic visualization of fungi and fungal elements in skin, hair, nails, and even vaginal secretions, Currently, it was determined that these activators solution were found to be a safe and effective treatment of plane warts. Despite the developments in the studies relating to GPC made by various precursors such as fly-ash and slag in the literatures, the use of GPC made by fly-ash and bottom-ash has not been overly researched. In this study, attempts have been made to produce a unique mix proportion for Potassium-based GPC made by fly-ash and bottom-ash and investigate various mechanical properties of this type of GPC including elastic modulus, freeze-thaw resistance, heavy metal leach-ability and corrosion in both laboratory and real environmental conditions using Non-Destructive Tests (NDT)s. / Graduate / 2021-12-15

The thesis is focused on the application of brick powder in production of binary alkali-activated binders with metakaolin, slag and fly ash. The theoretical part summarizes recent fields of use of the ceramic waste in construction and binder industry and prerequisite properties of the brick powder for alkaline activation. Brick powder based geopolymers made in the experimental work were tested for their mechanical properties, porosity and microstructure, flow properties of the fresh geopolymers were evaluated by rheometric measurements. In accordance with the results it can be concluded that brick powder could be a suitable precursor for blended binders with metakaolin and slag, these samples exhibited good mechanical properties and microstructure characteristics. The combination with fly ash was less applicable due to a rapid setting, hardening retarder used in these binders caused significant deterioration of the mechanical properties of the material.

The diploma thesis is focused on the use of the waste glass with different fineness on alkali - activated composites, mainly based on slag and fly ash. The theoretical part is focused on materials that are most used for alkaline activation - slag, fly ash and their composites with waste glass. The theoretical part also deals with the alkaline activation of composites from these materials and the factors that influences the microstructure and properties of these composites. In the experimental part were prepared composites from slag and fly ash with a waste glass as substitute. These composites then have been examined on mechanical properties and microstructure, also how different fineness of glass influences these properties. Then it will be decided whether it is economically advantageous grinding waste glass to finer fractions

V mnoha oborech jsou stále využívána anorganická filtrační media založená na materiálech, jejichž výroba využívá primární suroviny. Jejich výroba je tedy energeticky náročná a v důsledku nákladná a neohleduplná k životnímu prostředí. Cílem této práce je ověřit možnost využití alkalicky aktivovaných materiálů na bázi sekundárních surovin, především vysokopecních strusek (BFS) a popílků z uhelných elektráren (FA), pro výrobu porézních médií schopných v budoucnosti nahradit keramické a jiné anorganické filtry. Výzkum je rozvinut skrze experimentální design založený na výpočetním schématu samostatně vyvinutém s pomocí programu MATLAB. Toto schéma počítá vhodná složení směsí na základě poměrů obsahu nejdůležitějších oxidů ve vstupních surovinách. Tak je zajištěno zohlednění proměnlivého složení vstupních surovin a práce je tím hodnotnější, že její výsledky jsou skrze početní nástroj zohledňující základní oxidové složení surovin zobecnitelné. Zároveň byly však pro srovnání a lepší názornost závislostí vlastností na složení navrhnuty a připraveny i série vzorků založené vždy pouze na jedné ze surovin. Z výsledků vyplývá, že pevnost vzorků z těchto směsí (vytvrzených 24 hodin při 70 °C) ve čtyřbodové ohybové zkoušce dle ČSN EN 12390 5 může přesáhnout 7,6 MPa. Dosažením co možná nejvyšší porozity však zákonitě negativně ovlivňuje pevnost materiálu a výsledný materiál tedy dosahuje pevnosti těsně nad hranicí 6,3 MPa. Výsledky obecně dokazují, že nejvíce je pevnost materiálů ovlivněna poměrem SiO2/Al2O3 a množstvím alkalického aktivátoru. Z výsledků vyplývá, že alkalicky aktivované materiály (AAM) na bázi strusky dosahují i více než dvojnásobné pevnosti analogických materiálů na bázi elektrárenského popílku. Velikost pórů materiálů připravených z tříděných surovin s velikostí zrna od desítek po lehce přes sto mikronů se ve většině případů pohybuje v rozmezí desetin ž jednotek mikronů, v případě výsledného materiálu je to pak přibližně 0,2 mikronu. Celková porozita lisovaných těles se pohybuje těsně pod 40 %, což je v tomto případě téměř dvojnásobek ve srovnání s totožnými materiály na bázi netříděných surovin. Výsledky rovněž ukazují, že materiály na bázi strusky vykazují nižší porozitu než ty na bázi popílku, což je patrně způsobeno rozdílnou morfologií částic obou materiálů – částice strusky jsou nepravidelně hranaté a částice popílku kulaté. V průběhu experimentální činnosti byla pozorována tvorba výkvětů u materiálů na bázi elektrárenských popílků. Pomocí Energo-disperzní spektroskopické analýzy (EDS) byly výkvěty identifikovány jako hydroxid sodný procházející karbonatací za účasti vzdušného CO2. Test permeability vyžadoval, kvůli velmi jemné povaze porézní struktury, přípravu asymetrických filtračních přepážek. Tyto přepážky dosáhli propustnosti 138 L/h.m2.bar pro vodu a 1320 L/h.m2.bar pro vzduch.

This thesis deals with measurement of hardness and microhardness in relation to structure of homogeneous and heterogeneous materials. In the introduction basic theoretical background is commented, i.e. definitions, terminology, principles of measuring techniques for estimation of hardness, microhardness, tensile strength, compressive strength and bending strength. Follows a brief review of present research results focused on use of described principles in materials engineering. Then the experimental equipment and sample preparation is described. The crucial part of the thesis is summary of achieved results of original measurement and discussion of their relations to each other. Finally, the groundbreaking estimation is described, showing the correlation of chemical composition gradient and mechanical properties in interfacial zone of geopolymeric material.

This thesis concerns on substitution of blast furnace slag or its part with fly ash in alkali-activated systems based on aluminosilikates. Classic, fluid bottom and fluid filter fly ashes will be tested. The goal is to prepare geopolymer with required mechanical properties, but with maximal admixture of alternative raw materials. In composites with substitutioned slag or its part the thesis focuses mainly on workabilityof fresh mixture, pressure and bending strenght. Use of secondary raw materials has advantages in the economic point of view and it´s friendly to enviroment, too.