Almost all research on biorefinery concepts are based on chemical pulping processes and ways of utilising lignin, hemicelluloses and extractives as well as a part of the remaining cellulose for production of nano materials in order to create more valuable products than today. Within the Forest as a Resource (FORE) research program at FSCN we are utilising the whole chain of unit processes from forestry to final products as paper and board, where the pulping process research focus on high yield process as TMP and CTMP. As these process solutions are preserving or only slightly changing the properties of the original wood polymers and extractives, the idea is to find high value adding products designed by nature. From an economic perspective, the production of nanocellulose from a chemical pulp is quite expensive as the pulp has to be either enzymatically (e.g. mono-component endoglucanase) pre-treated or chemically oxidised using the TEMPO (2,2,6,6 - tetramethyl-piperidine-1-oxil) - mediated oxidation method in order to make it possible to disrupt the fibres by means of homogenisation. In high yield pulping processes such as in TMP and CTMP, the idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nano-ligno-cellulose (NLC). The integration of a NLC unit process in a high yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and board grades. The intention of this research work was that, by using this concept, a knowledge base can be created so that it becomes possible to develop a low-cost production method for its implementation. In order to study the potential of this concept, treatment of thermo-mechanical pulp (TMP) fines fractions were studied by means of homogenisation It seems possible to homogenise fine particles of thermo-mechanical pulp (1% w/v) to NLC. A correspond fines fraction from bleached kraft pulp (BKP) was tested as a reference at 0.5% w/v concentration. The objective presented in this work was to develop a methodology for producing mechanical pulp based NLC from fines fractions and to utilise this material as strength additives in paper and board grades. Laboratory sheets of CTMP and BKP, with addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp fibres blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities. The characterisation of the particle size distribution of NLC is both important and challenging and the crill methodology developed at Innventia (former STFI) already during the 1980s was tested to see if it would be both fast and reliable enough. The crill measurement technique is based on the optical responses of a micro/nano particle suspension at two wavelengths of light; UV and IR. The crill value of TMP and CTMP based nano-ligno-cellulose were measured as a function of the homogenisation time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time.

Les poussières émises par l'industrie métallurgique concourent à la qualité de l'air des zones urbaines voisines. Ces particules, émises par des procédés à "haute température", sont susceptibles d'évoluer rapidement au sein des panaches. L'objectif de l'étude est de caractériser la phase particulaire sur un site d'émission métallurgique et de déterminer la nature et l'amplitude des transformations physico-chimiques subies par ces particules dans les premières minutes de leur émission. Des prélèvements d'aérosols ont été réalisés au sein des cheminées et dans l'environnement proche d'une usine métallurgique (production d'alliage de ferromanganèse), dont l'atelier d'agglomération est le principal émissaire. Le spectre granulométrique des particules dans l'environnement montre un enrichissement de nanoparticules (10-100nm) après survol des masses d'air au dessus du site industriel. Les rejets caractéristiques de l'usine (émission d'oxydes de fer et de manganèse, mais également d'aluminosilicates) se trouvent la plupart du temps sous forme d'agglomérats de composition chimique hétérogène et de structure morphologique complexe. Ces agglomérats semblent évoluer rapidement par adsorption de composés organiques volatils ou de suies. L'étude de la spéciation du Fe et du Mn au sein de ces particules indique qu'elles sont sujettes à des réactions d'oxydation via des mécanismes de conversion gaz/particules au sein même du procédé industriel, aboutissant notamment à une oxydation du fer inversement proportionnelle à la taille des particules. Par contre, aucune évolution significative du degré d'oxydation du Fe et du Mn n'a été observée dans l'environnement proche de l'émissaire.

[Formulae and special characters can not be reproduced here. Please see the pdf version of the Abstract for an accurate reproduction.] The thesis provides a comprehensive study on the behaviour of sand with a small amount of fines [i.e.1/3 plastic fines and 2/3 non-plastic fines]. The work is carried out experimentally under axi-symmetric conditions using the triaxial apparatus. Conventional drained triaxial tests are conducted on isotropic consolidated specimens and all the tests indicate that sand with fines does not manifest any unusual behaviour under drained conditions. However in undrained shearing the so-called ???reverse behaviour??? is noted. The study demonstrates that the reverse behaviour conforms to the critical state framework because significant changes in the position and geometry of the critical state [CS] and isotropic consolidation [IL] lines are caused by the presence of fines. These changes cannot be adequately modelled by the intergranular void ratio as proposed by Thevanayagam and Mohan (2000). This study also demonstrates that the original state parameter [special character] as proposed by Been and Jefferies (1985) is not an adequate parameter to predict the undrained behaviour trend. A new parameter termed ???modified state parameter??? [special character] is proposed to account for the combined effects of density and confining pressure. The suitability of the modified state parameter to characterise the response of parent sand and sand with fines is assessed for a range of void ratios and confining pressures. The effect of drained stress history is an important factor affecting the subsequent undrained response. Drained pre-shearing to failure is found to improve considerably the subsequent undrained response to the extent that liquefaction may not occur. Different drained pre-shearing histories have different effects on the undrained response. However in these tests [special character] has limitations in quantifying the subsequent undrained stress-strain response. Hence, a new framework of ???yielding parameter??? [special character] extends the capability of [special character] and additional data is presented to demonstrate the suitability of this concept. The implementation of [special character] depends on whether the previous stress state reached during the stress history is below or at failure. The effects of drained pre-shearing on the position and movement of failure surface are investigated. It is found that drained pre-shearing to failure at larger confining pressures has the effect of shifting upwards part of the drained failure surface. The shift at larger stress ratios [special character] may be described in terms of dilatancy and modified state parameter at failure. The so-called strain path tests are conducted to study the influence of strain increment ratio on the deformation behaviour of sand with fines. It is found that the value of [special character] has significant effects on the stress-strain behaviour. Along negative [special character] paths the soil strain softens in the form of decreasing the shear resistance before reaching the failure state. In contrast, along positive [special character] paths the soil strain hardens to an asymptotic stress ratio. The asymptotic stress ratio decreases with increasing [special character] along a linear relationship. The framework of [special character] cannot quantify the stress-strain response along positive and negative strain paths. Consequently an ???instability parameter??? [special character] is proposed to extend the capabilities of [special character] and the reliability of this parameter is further assessed. The behaviour along a range of positive and negative [special character] paths is investigated on pre-sheared specimens. In negative [special character] the effective stress paths reach a surface located higher than the monotonic failure surface on which they trace downward towards the origin of stress space. The results indicate this surface may be the same as the drained failure envelope which has been shifted as a result of drained pre-shearing. In positive [special character] paths a large improvement is noted in both the strength and stiffness of the soil. Note The parameters [special character] and [special character] are all generalisations of [special character] so that the behaviour under complex conditions can be characterised.

The expansion of the construction is of great importance for the economic development of the country, due to the prominent position the sector takes in economy, creating jobs, enabling housing, income and infrastructure. However, it is also responsible for serious environmental problems related to the construction processes. Given the current concern about sustainability, recycling of waste from construction and demolition (WCD), it is very important because it reduces environmental impacts such as the extraction of raw natural material and pollution caused by improper disposal of these materials. The recycled waste may be applied in various uses in the construction and the use of recycled sand mortar coating is one of the most viable, since they are not subject to structural efforts. In this study, the research was carried out against the influence of fines content of recycled aggregates in coating mortars. Therefore, mixtures containing 20%, 30%, 40% and 50% of natural aggregate replaced by crushed and sieved recycled aggregate (without fines), had their performance compared to mixtures containing crushed and unsieved recycled aggregate (with fines) and to the reference mixture, which contains as aggregate the natural sand. The WCD, provided by company of Santa Maria, are a mixed of bricks, ceramic blocks, tiles, mortars, concrete waste, rocks and ceramic floors. The materials ratio used was 1: 2: 8 (cement: lime: dry fine aggregate) by volume and the recycled aggregate substitutions for natural aggregate were made by volume. To evaluate the influence of the fines content in mortars with recycled aggregates, were analyzed the main properties of mortars in the fresh state and hardened state and the performance of some of these mortars in a coating system. The study concludes that, mortars with recycled and sieved aggregate showed better properties and lower susceptibility to cracking, relative to mortars with unsieved aggregate. Among they, the mortar with a 30% replacement of natural aggregate by crushed and sieved recycled aggregate, presented the best set of properties. / A expansão da construção civil é de grande importância para o desenvolvimento econômico do país, devido à posição de destaque que o setor ocupa na economia, com geração de empregos, viabilização de moradias, renda e infraestrutura. No entanto, é também responsável por graves problemas ambientais relacionados aos processos construtivos. Diante da atual preocupação com sustentabilidade, a reciclagem dos resíduos de construção e demolição (RCD), é muito importante, pois reduz impactos ambientais como a extração de matéria prima natural e a poluição, causada pela destinação inadequada desses materiais. Os resíduos reciclados podem ser aplicados em diversos usos na construção civil e a utilização de areia reciclada em argamassas de revestimento, é uma das mais viáveis, visto que não estão sujeitas a esforços estruturais. Neste trabalho, foi realizada a investigação, frente à influência do teor de finos dos agregados reciclados nas argamassas de revestimento. Para isso, misturas, com 20%, 30%, 40%, e 50% de substituição de agregado natural por agregado reciclado britado e peneirado (sem finos), tiveram seu desempenho comparado ao das misturas contendo agregado reciclado britado não peneirado (com finos) e à mistura de referência, contendo como agregado areia natural. Os RCD, fornecidos pela usina de reciclagem de Santa Maria são mistos, provenientes de tijolos e blocos cerâmicos, telhas, argamassas, resíduos de concreto, rochas e pisos cerâmicos. O traço utilizado foi 1:2:8 (cimento: cal: agregado miúdo) em volume, com o agregado miúdo seco e as substituições de agregado reciclado por agregado natural foram feitas em massa. Para avaliar a influência do teor de finos nas argamassas com agregados reciclados, foram analisadas as principais propriedades das argamassas no estado fresco e endurecido e o desempenho de algumas dessas argamassas em um sistema de revestimento. No estudo concluiu-se que as argamassas com agregado reciclado peneirado apresentaram melhores propriedades e menor susceptibilidade à fissuração, em relação às argamassas com agregado não peneirado. Entre elas, a argamassa com 30% de substituição de agregado natural por agregado reciclado britado e peneirado, foi a que apresentou melhor conjunto de propriedades.

A injeção de carvão pulverizado (PCI — pulverized coal injection) nos altos-fornos (AFs) é uma tecnologia utilizada pelas usinas siderúrgicas para aumentar a produtividade e diminuir o consumo de coque no AF. Nas últimas décadas as taxas de injeção de carvão pulverizado aumentaram na maior parte dos AFs. O principal problema associado à utilização de altas taxas de PCI é a geração de char (carvão incombusto) na zona de combustão. Este material percorre um caminho ascendente junto ao fluxo gasoso, podendo acumular-se e assim prejudicar a permeabilidade do AF. A presença, nas amostras sólidas recolhidas do gás de saída do AF, de altos teores de char pode ser o resultado da injeção de um carvão pulverizado com uma combustibilidade inadequada e de uma operação instável do AF. Portanto, conhecer a proporção de char que sai do AF contribuirá na seleção do tipo de carvão utilizado e na otimização da prática de PCI. Análises químicas das amostras de pó do AF revelam, sem distinguir, a presença de materiais carbonosos. A microscopia ótica foi utilizada para estudar estas amostras sólidas, mas apresenta certas limitações. A difração de raios-X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar as dimensões dos cristalitos (Lc, La, etc.) dos materiais carbonosos. Uma vez que a estrutura do coque é mais ordenada que a do char, seria possível quantificar a proporção destes materiais nas amostras de pó do AF através da DRX combinada a análises químicas. O objetivo principal deste trabalho foi identificar e quantificar os componentes carbonosos (char e finos de coque) presentes no pó de balão (PB) do AF, por DRX e análise elementar de carbono. O efeito da temperatura sobre a grafitização do coque também foi avaliado, a fim de identificar a possível origem dos finos de coque gerados no AF. Três amostras de PB coletadas de um AF, uma em operação a coque e duas a PCI, foram selecionadas. Os pós foram fracionados e analisados quimicamente. Após, as frações destas amostras foram moídas, desmineralizadas e analisadas por DRX e análise elementar de carbono. Amostras de char produzidas em laboratório e respectivos carvões foram utilizados como padrões para a quantificação. Amostras de coque foram tratadas termicamente a diferentes temperaturas, sendo posteriormente analisadas por DRX. Este estudo mostrou que a DRX pode ser usada como técnica padrão para identificar as estruturas do char e do coque podendo ser utilizada para quantificar a proporção destes materiais carbonosos no pó de balão do AF. Além disto, observou-se que quanto maior a temperatura de tratamento térmico mais ordenada fica a estrutura cristalina do coque. / In a Blast Furnace (BF), Pulverized coal injection (PCI) is the most popular injection technology used worldwide to reduce coke consumption and to increase the productivity. In the last decades the PCI injection rates raised in the most of BFs. One of the problems during the PCI operation in BF is the unburnt char formation. Higher char levels in the BF stack could impact burden permeability. The off gas BF solid samples contain char, coke fines, metallic oxides, etc. The quantification of the carbonaceous materials content in these samples could be used to improve the PCI performance in operating BF. Chemical analysis in the BF dust samples reveal without differentiates some carbonaceous material. The optical microscopy was used to study these solid samples but with some restrictions. XRD (X-ray diffraction) is a standard means of characterizing the structure of materials. This technique has been utilized to determine the crystallite sizes (Lc, La, etc.), in carbonaceous materials. Since the coke structure is more ordered than the char structure, it would be possible to quantify the proportion of these materials in the off-gas BF samples by chemical analysis in combination with XRD. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the flue dust BF samples through the use of the XRD technique and ultimate analysis. Besides, the effect of temperature on coke graphitization will be studied aiming to identify the possible origin of coke fines in the BF dust. Four dusts collected in the off-gas BF, two at all coke and two at PCI operations, were selected for this investigation. The dusts were fractioned and chemically analyzed. After the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. Besides, were investigated the atomic structure of raw coals and its laboratory char, and raw coke and its laboratory heattreated samples. This study has shown that the XRD technique could be used as a standard procedure to identify the char and coke structures and could be used to quantify the fines proportions of these carbonaceous materials in the BF flue dust. It was concluded that the bigger the annealing temperature the more ordered becomes the atomic coke structure.

Dans l’industrie automobile, les exigences en matière d’émissions polluantes conduisent à alléger les véhicules, notamment en réduisant l’épaisseur des tôles. Ce travail en partenariat avec ArcelorMittal porte sur le soudage par résistance par point de tôles fines d’acier. L’objectif est d’identifier les phénomènes qui induisent les difficultés de soudabilité opératoire rencontrées avec une combinaison dissymétrique de trois tôles revêtues, incluant une tôle très mince galvanisée de moins de 0,6 mm, une tôle de DP600 et une tôle en Usibor® emboutie à chaud. Des observations par caméra infrarouge montrent que les échauffements initiaux se produisent principalement au niveau des interfaces avec la tôle d’Usibor®1500, et que le noyau se forme du côté de cette tôle, loin de la tôle mince. Les valeurs très élevées des résistances de contact électrique et thermique, mesurées aux interfaces avec la tôle d’Usibor®, sont imputables au revêtement Alusi® et sont à l’origine des forts échauffements initiaux observés à ces interfaces. Un modèle numérique, limité aux aspects électrothermiques et développé sur COMSOL Multiphysics®, a permis de montrer que la zone fondue s’initie très rapidement dans la tôle d’Usibor® 1500 sous l’effet des fortes résistances de contact adjacentes, et que son développement en épaisseur et diamètre est piloté par les évolutions des rayons de contact électrode-tôle. Les résistances de contact entre électrode et tôle mince, le profil du courant de soudage et les rayons de courbure des faces actives des électrodes sont les paramètres prépondérants à optimiser pour améliorer la pénétration du noyau dans la tôle mince. / In the automotive industry, the requirements for polluting emissions lead to light vehicles, especially in decreasing the steel sheet thickness. This work in partnership with ArcelorMittal focuses on resistance spot welding of steel sheets. The aim is to identify the phenomena that induce operating weldability difficulties encountered with an asymmetrical stack of three coated steel sheets, including a very thin galvanized sheet of less than 0.6 mm, a sheet of DP600, and a hot stamped Usibor® sheet. Infrared camera observations show that the initial heating takes placeat the interfaces with the Usibor®1500 sheet, and that the nugget appears inside this sheet, away from the thin sheet. The very high values of the electrical and thermal contact resistances, measured at the interfaces with the Usibor®1500 sheet, are due to the Alusi® coating and are at the origin of the strong initial heating at these interfaces. A numerical model, limited to the electro- thermal aspects and developed with COMSOL Multiphysics®, shows that the nugget is initiated very quickly in Usibor®1500 sheet under the effect of adjacent contact resistances, and that its development is driven by the evolutions of the electrode-sheet contact areas. The contact resistances between the electrode and the thin sheet, the welding current evolution, and the curvature radius of electrode tips are the most efficient parameters to be optimized to improve the penetration of the nugget in the thin sheet.

A injeção de carvão pulverizado (PCI — pulverized coal injection) nos altos-fornos (AFs) é uma tecnologia utilizada pelas usinas siderúrgicas para aumentar a produtividade e diminuir o consumo de coque no AF. Nas últimas décadas as taxas de injeção de carvão pulverizado aumentaram na maior parte dos AFs. O principal problema associado à utilização de altas taxas de PCI é a geração de char (carvão incombusto) na zona de combustão. Este material percorre um caminho ascendente junto ao fluxo gasoso, podendo acumular-se e assim prejudicar a permeabilidade do AF. A presença, nas amostras sólidas recolhidas do gás de saída do AF, de altos teores de char pode ser o resultado da injeção de um carvão pulverizado com uma combustibilidade inadequada e de uma operação instável do AF. Portanto, conhecer a proporção de char que sai do AF contribuirá na seleção do tipo de carvão utilizado e na otimização da prática de PCI. Análises químicas das amostras de pó do AF revelam, sem distinguir, a presença de materiais carbonosos. A microscopia ótica foi utilizada para estudar estas amostras sólidas, mas apresenta certas limitações. A difração de raios-X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar as dimensões dos cristalitos (Lc, La, etc.) dos materiais carbonosos. Uma vez que a estrutura do coque é mais ordenada que a do char, seria possível quantificar a proporção destes materiais nas amostras de pó do AF através da DRX combinada a análises químicas. O objetivo principal deste trabalho foi identificar e quantificar os componentes carbonosos (char e finos de coque) presentes no pó de balão (PB) do AF, por DRX e análise elementar de carbono. O efeito da temperatura sobre a grafitização do coque também foi avaliado, a fim de identificar a possível origem dos finos de coque gerados no AF. Três amostras de PB coletadas de um AF, uma em operação a coque e duas a PCI, foram selecionadas. Os pós foram fracionados e analisados quimicamente. Após, as frações destas amostras foram moídas, desmineralizadas e analisadas por DRX e análise elementar de carbono. Amostras de char produzidas em laboratório e respectivos carvões foram utilizados como padrões para a quantificação. Amostras de coque foram tratadas termicamente a diferentes temperaturas, sendo posteriormente analisadas por DRX. Este estudo mostrou que a DRX pode ser usada como técnica padrão para identificar as estruturas do char e do coque podendo ser utilizada para quantificar a proporção destes materiais carbonosos no pó de balão do AF. Além disto, observou-se que quanto maior a temperatura de tratamento térmico mais ordenada fica a estrutura cristalina do coque. / In a Blast Furnace (BF), Pulverized coal injection (PCI) is the most popular injection technology used worldwide to reduce coke consumption and to increase the productivity. In the last decades the PCI injection rates raised in the most of BFs. One of the problems during the PCI operation in BF is the unburnt char formation. Higher char levels in the BF stack could impact burden permeability. The off gas BF solid samples contain char, coke fines, metallic oxides, etc. The quantification of the carbonaceous materials content in these samples could be used to improve the PCI performance in operating BF. Chemical analysis in the BF dust samples reveal without differentiates some carbonaceous material. The optical microscopy was used to study these solid samples but with some restrictions. XRD (X-ray diffraction) is a standard means of characterizing the structure of materials. This technique has been utilized to determine the crystallite sizes (Lc, La, etc.), in carbonaceous materials. Since the coke structure is more ordered than the char structure, it would be possible to quantify the proportion of these materials in the off-gas BF samples by chemical analysis in combination with XRD. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the flue dust BF samples through the use of the XRD technique and ultimate analysis. Besides, the effect of temperature on coke graphitization will be studied aiming to identify the possible origin of coke fines in the BF dust. Four dusts collected in the off-gas BF, two at all coke and two at PCI operations, were selected for this investigation. The dusts were fractioned and chemically analyzed. After the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. Besides, were investigated the atomic structure of raw coals and its laboratory char, and raw coke and its laboratory heattreated samples. This study has shown that the XRD technique could be used as a standard procedure to identify the char and coke structures and could be used to quantify the fines proportions of these carbonaceous materials in the BF flue dust. It was concluded that the bigger the annealing temperature the more ordered becomes the atomic coke structure.

A injeção de carvão pulverizado (PCI — pulverized coal injection) nos altos-fornos (AFs) é uma tecnologia utilizada pelas usinas siderúrgicas para aumentar a produtividade e diminuir o consumo de coque no AF. Nas últimas décadas as taxas de injeção de carvão pulverizado aumentaram na maior parte dos AFs. O principal problema associado à utilização de altas taxas de PCI é a geração de char (carvão incombusto) na zona de combustão. Este material percorre um caminho ascendente junto ao fluxo gasoso, podendo acumular-se e assim prejudicar a permeabilidade do AF. A presença, nas amostras sólidas recolhidas do gás de saída do AF, de altos teores de char pode ser o resultado da injeção de um carvão pulverizado com uma combustibilidade inadequada e de uma operação instável do AF. Portanto, conhecer a proporção de char que sai do AF contribuirá na seleção do tipo de carvão utilizado e na otimização da prática de PCI. Análises químicas das amostras de pó do AF revelam, sem distinguir, a presença de materiais carbonosos. A microscopia ótica foi utilizada para estudar estas amostras sólidas, mas apresenta certas limitações. A difração de raios-X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar as dimensões dos cristalitos (Lc, La, etc.) dos materiais carbonosos. Uma vez que a estrutura do coque é mais ordenada que a do char, seria possível quantificar a proporção destes materiais nas amostras de pó do AF através da DRX combinada a análises químicas. O objetivo principal deste trabalho foi identificar e quantificar os componentes carbonosos (char e finos de coque) presentes no pó de balão (PB) do AF, por DRX e análise elementar de carbono. O efeito da temperatura sobre a grafitização do coque também foi avaliado, a fim de identificar a possível origem dos finos de coque gerados no AF. Três amostras de PB coletadas de um AF, uma em operação a coque e duas a PCI, foram selecionadas. Os pós foram fracionados e analisados quimicamente. Após, as frações destas amostras foram moídas, desmineralizadas e analisadas por DRX e análise elementar de carbono. Amostras de char produzidas em laboratório e respectivos carvões foram utilizados como padrões para a quantificação. Amostras de coque foram tratadas termicamente a diferentes temperaturas, sendo posteriormente analisadas por DRX. Este estudo mostrou que a DRX pode ser usada como técnica padrão para identificar as estruturas do char e do coque podendo ser utilizada para quantificar a proporção destes materiais carbonosos no pó de balão do AF. Além disto, observou-se que quanto maior a temperatura de tratamento térmico mais ordenada fica a estrutura cristalina do coque. / In a Blast Furnace (BF), Pulverized coal injection (PCI) is the most popular injection technology used worldwide to reduce coke consumption and to increase the productivity. In the last decades the PCI injection rates raised in the most of BFs. One of the problems during the PCI operation in BF is the unburnt char formation. Higher char levels in the BF stack could impact burden permeability. The off gas BF solid samples contain char, coke fines, metallic oxides, etc. The quantification of the carbonaceous materials content in these samples could be used to improve the PCI performance in operating BF. Chemical analysis in the BF dust samples reveal without differentiates some carbonaceous material. The optical microscopy was used to study these solid samples but with some restrictions. XRD (X-ray diffraction) is a standard means of characterizing the structure of materials. This technique has been utilized to determine the crystallite sizes (Lc, La, etc.), in carbonaceous materials. Since the coke structure is more ordered than the char structure, it would be possible to quantify the proportion of these materials in the off-gas BF samples by chemical analysis in combination with XRD. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the flue dust BF samples through the use of the XRD technique and ultimate analysis. Besides, the effect of temperature on coke graphitization will be studied aiming to identify the possible origin of coke fines in the BF dust. Four dusts collected in the off-gas BF, two at all coke and two at PCI operations, were selected for this investigation. The dusts were fractioned and chemically analyzed. After the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. Besides, were investigated the atomic structure of raw coals and its laboratory char, and raw coke and its laboratory heattreated samples. This study has shown that the XRD technique could be used as a standard procedure to identify the char and coke structures and could be used to quantify the fines proportions of these carbonaceous materials in the BF flue dust. It was concluded that the bigger the annealing temperature the more ordered becomes the atomic coke structure.

La poudre de silicium métallurgique (MG-Si, pureté 99 %) ont été étudiées, en se focalisant particulièrement sur les particules fines (taille comprise entre 1 et 10 μm) Ce matériau est utilisé dans l’industrie siliconière pour la synthèse directe du diméthyldichlorosilane et est obtenu par broyage de blocs de silicium. Les propriétés de cette poudre sont cruciales pour le procédé industriel, à la fois en termes de surface spécifique, composition chimique et coulabilité. Comprendre l’influence des particules fines, qui dégradent la coulabilité, et leur origine au cours du broyage est donc d’une importance cruciale. Une nouvelle caractérisation, chimique et cristallographique, des poudres de MG-Si montre que les particules fines sont en moyennes moins chargées en éléments d’alliage que les particules plus grosses. La structure cristalline du silicium est inchangée au cours du broyage, sauf pour les particules superfines (taille inférieure à 1 μm). Celles-ci présentent des zones amorphes : cela montre qu’elles sont soumises à des contraintes plus importantes au cours du broyage, comme cette transformation étant obtenue au-delà d’un seuil de pression. Le comportement du MG-Si en broyage a été étudié pour la première fois. A l’échelle de la particule unique, il est confirmé que les fissures suivent une propagation transgranulaire. De plus, des particules fines peuvent être produites au cours d’un unique événement de broyage, en raison de l’activation simultanée de multiples systèmes de fissures qui peuvent brancher entre elles. La taille critique en-deçà de laquelle la déformation plastique est énergétiquement plus favorable que la propagation de fissure a été estimée à environ 1 μm par une méthode basée sur l’indentation. Ces deux résultats sont cohérents avec la répartition des éléments d’alliages en fonction de la taille de particule. A l’échelle multiparticulaire, une étude pilote en broyeur à tambour tournant a été menée. Les résultats de cette étude ne sont pas disponibles dans cette version publique du manuscrit. Veuillez vous reporter au manuscrit complet. Les conséquences sur la coulabilité de la présence de particules fines dans la poudre de MG-Si produite par broyage ont été caractérisées par mesures d’angle de repos, de dynamique de compaction et en fluidisation. En particulier, un nouveau comportement d’élutriation a été identifié et décrit : l’élutriation séquentielle se produit lorsque des particules fines sont initialement présentes dans le lit fluidisé et se caractérise par l’envolement d’abord des inférieures à environ 30 μm puis seulement des particules de taille supérieure. Ce comportement n’est pas observé en l’absence de fines dans le lit initial. L’explication de ce phénomène pourrait se trouver dans la formation de clusters polydisperses, formés seulement en présence de particules fines. En parallèle de l’élutriation séquentielle, des mesures électrostatiques avec un électromètre externe à la colonne ont montré la présence de potentiels très importants (10 kV), dont le signe correspond à la gamme de taille de particules envolées. Ceci suggère que l’adhésion au sein des clusters pourrait être électrostatique. / Metallurgical-grade silicon (MG-Si, 99 %) powders were extensively investigated, particularly focusing on the fine particles (whose size is between 1 and 10 μm) comprised in these powders. This material is a reactant widely used in the silicones industry for the Direct Synthesis and is obtained by size reduction of millimetric silicon lumps. Powder properties are major stakes of the industrial process. Smaller sizes favor high specific surfaces and high rates of production, but can decrease the lowability, thus inducing poor heat evacuation resulting in hot spots and a decrease in selectivity. Such lowability issues are particularly associated with fine particles, hence understand the generation of these particles during grinding is of critical importance. New chemical and crystallographic characterization of MG-Si is presented, showing that fine particles contain on average less alloying elements than larger particles, yet their crystallographic structure is preserved through grinding. On the contrary, superfine particles (smaller than 1 μm) exhibit amorphous zones: this transformation is pressure induced, showing that these particles experience larger stresses during the grinding step. The behavior of MG-Si in grinding mills has been studied for the first time. At the single particle level, it has been confirmed that transgranular fracture is preferred in MG-Si. Moreover, fine particles can be produced from a single fracture event, due to multiple crack propagation and branching. The critical size under which plastic deformation preferentially occurs over fracture has been evaluated to be approximately 1 μm. These two facts are consistent with a lower level of impurities in fines, yet remaining crystalline, and with superfines exhibiting amorphous areas. At the multiple particle level, pilot scale batch milling experiments have been performed. The results are not included in this public version of the manuscript, please refer to the full manuscript. The consequences of the presence of fine particles in ground MG-Si powder on lowability has been assessed by means of angle of repose, compaction tests and fluidization experiments. A new elutriation behavior has been observed and characterized: for naturally ground MS-Si powders (including fine particles), particles smaller than 30 μm are entrained first, then only larger particles. This was not the case in absence of fine particles. The explanation may probably lie within the presence of polydisperse clusters, formed only in presence of fine particles. Parallel to this elutriation behavior, electrostatic measurements with an external electrometer showed that high potential with sign correlated with the type of particle elutriated are attained during elutriation. This may suggest that electrostatics is responsible for cluster formation.

L'objectif de cette thèse est de réaliser un bilan des aérosols atmosphériques sur le bassin méditerranéen et de caractériser la qualité de l'air de cette région en se focalisant sur des indicateurs d'exposition à long terme. Basés sur des simulations du modèle de chimie-transport MOCAGE, (MOdèle de Chimie Atmosphérique à Grande Échelle), les travaux portent dans un premier temps sur le développement d'un module permettant de prendre en compte les aérosols inorganiques secondaires. Ce module a été validé à différentes échelles et avec différents types de données. Le modèle MOCAGE a ensuite servi à simuler la composition chimique de l'atmosphère sur le bassin méditerranéen pour l'année 2013. Nous avons ainsi pu montrer que le bassin méditerranéen est une région exportatrice d'aérosols. Nous avons également étudié l'impact des émissions anthropiques maritimes et côtières sur le bilan des aérosols et la qualité de l'air dans la région méditerranéenne. / The objective of this thesis are to establish a budget of the atmospheric aerosols on the Mediterranean basin and to characterize air quality over this region based on long term exposition indicators. Based on simulations made with the chemical transport model MOCAGE (Modèle de Chimie Atmosphérique à Grande Échelle), the first part of this work is devoted to the development of a secondary inorganic aerosols module. This module was validated at different scales using a large variety of types of data. The MOCAGE model has then been used to simulate the chemical composition on the Mediterranean basin over the year 2013. We were able to show that the Mediterranean area is an export zone for aerosols. We also studied the impact of marine and coastal anthropogenic emissions on the aerosol budget and the air quality in the basin.