A reação álcali-agregado é uma manifestação patológica diretamente ligada à seleção dos materiais (cimento, agregados miúdo e graúdo, água e aditivos) que pode comprometer a durabilidade das estruturas de concreto, uma vez que a interação desses materiais e as condições ambientais é que vão conferir ao concreto determinadas propriedades ligadas à sua vida útil. A reação entre os hidróxidos alcalinos solubilizados na fase líquida dos poros dos concretos e alguns agregados reativos é lenta e resulta em um gel que, ao se acumular em vazios do concreto e na interface pasta-agregado, na presença de água, se expande, exercendo pressão interna no concreto. Ao exceder a resistência à tração do concreto, a pressão interna pode promover fissurações. A reação álcali-agregado requer a atuação conjunta de água, agregado reativo e álcalis. Sua prevenção pode ser feita a partir da eliminação de um dos fatores, ou seja, a partir do emprego de agregados inertes ou de cimentos com baixos teores de álcalis ou isolamento da umidade. Na impossibilidade de eliminar um dos fatores, medidas preventivas devem ser tomadas para o emprego de agregados reativos em obras de construção civil. Entre essas, destacam-se a utilização de cimentos com baixos teores de álcalis ou a de cimentos com adições ativas mitigadoras da reação álcali-agregado: escória de alto-forno, cinza volante, metacaulim e sílica ativa, que foi o objeto de pesquisa do presente trabalho. No programa experimental foram analisados dois tipos de agregado potencialmente reativos com os hidróxidos alcalinos: EDVDOWR e PLORQLWR_ JUDQtWLFR. O primeiro, proveniente de rocha ígnea, tem como constituintes deletérios vidro, clorofeíta, calcedônia (sílica criptocristalina), que dará origem à reação do tipo iOFDOL_VtOLFD. O agregado milonito granítico provém de rocha metamórfica, tem como constituintes deletérios quartzo microgranular, quartzo recristalizado, quartzo com extinção ondulante e quartzo e feldspato deformados, que dará origem ao tipo de reação iOFDOL_VLOLFDWR. Com o objetivo de avaliar a eficiência de adições ativas em mitigar as reações, os agregados foram combinados com 16 cimentos com adições ativas. Escória de alto-forno foi adicionada a 15%, 30%, 45% e 60% e cinza volante, a 10%, 15%, 25% e 35%, teores normalmente encontrados nos cimentos brasileiros. Metacaulim foi adicionada a 5%, 10%, 15% e 20%, e sílica ativa, a 5%, 10% e 15%, teores representativos da faixa normalmente adicionada diretamente a concretos. Todos os materiais utilizados foram caracterizados química, física e mineralogicamente, incluindo a análise petrográfica dos agregados. As barras de argamassa foram analisadas ao MEV, microscópio óptico de luz transmitida, realizaram-se ensaios de porosimetria por intrusão de mercúrio e análises térmicas para quantificar a teor de portlandita residual, e determinou-se o teor de álcalis dentro das barras após a realização dos ensaios para verificar a migração de íons de sódio. Os resultados indicam que a eficiência das adições ativas varia de acordo com a composição química e mineralógica das adições, da proporção desse material no cimento, e do grau de reatividade do agregado. / The alkali-aggregate reaction is a pathologic manifestation that can induce the premature distress and loss in serviceability of concrete structures affected. It is directly associated to the selection of materials (cement, coarse and fine aggregates, water and additives), as the interaction between these materials and environmental condition will grant the concrete some of the properties related to its service life. The slow reaction between alkali hydroxides soluble in the liquid phase within concrete pores and reactive aggregates gives rise to a gel that piles up within concrete voids and the aggregate-paste interface. In presence of water, the gel expands and exerts internal pressure in the concrete. When the internal pressure exceeds the tensile strength, cracking may come up as result. The alkali-aggregate reaction requires the action of water, reactive aggregate and alkalis altogether. Prevention can be carried out by eliminating one of these factors, i.e. employing either inert aggregates or lowalkali cements, or keeping the concrete away from moisture. Otherwise, preventive measures must be taken when reactive aggregates are used in civil construction works, such as the use of low-alkali cements or composite cements bearing alkaliaggregate- reaction mitigating admixtures: blast-furnace slag, fly ash, metakaolin and silica fume, which are the object of the present research. The experimental work included the analysis of two potentially reactive aggregates to alkali hydroxides: basalt and granite milonite. The igneous basalt carries deleterious constituents such as glass, chloropheite (cryptocrystalline silica), that will give rise to the DONDOL_VLOLFD type reaction while the metamorphic granite milonite carries micro granular, recrystallized, undulate-extinction-bearing quartz and deformed feldspar grains, that give rise to DONDOL_VLOLFDWH type reaction. Aiming at evaluating how efficient in mitigating these reactions the active admixtures are, these aggregates were mixed with 16 composite cements. The contents of admixtures followed those usually found in Brazilian industrial cements for blast-furnace slag (15%, 30%, 45%, 60%) and fly ash (10%, 15%, 25%, 35%), and those generally added directly to concrete for metakaolin (5%, 10%, 15%, 20%) and silica fume (5%, 10%, 15%). All materials were characterized for their chemical composition, physical properties and mineralogy. Petrography was carried out on the aggregates. The mortar bars were analyzed at the scanning electronic and transmitted-light optical microscopes. Mercury-intrusion porosimetry and thermal analyses were carried out to quantify residual portlandite. The alkali content within the bars was determined in order to verify migration of Na+ ions. The results show that the efficiency of active admixtures varies according to their chemical and mineralogical composition and proportioning in cement, and to the aggregate reactivity.

A questão ambiental vem se tornando tema recorrente nos foros nacionais e internacionais, estando atualmente inserida na opinião pública, nas comunidades e sendo norteadora na geração de novos produtos e serviços na área industrial e comercial voltados para a sustentabilidade. Neste sentido, a indústria da construção é um dos principais causadores de impacto ambiental, pois consome consideráveis recursos naturais e gera grandes quantidades de resíduos. Sendo assim, a utilização de resíduos como matéria prima na indústria da construção possibilita benefícios ambientais e econômicos. Buscando avançar nesta discussão, a presente pesquisa procurou inserir dois resíduos (cinza volante e cal de carbureto), gerados na região metropolitana de Porto Alegre, como possibilidade de solução de Engenharia. Para isto, é necessário um estudo do seu comportamento mecânico decorrente da cimentação proporcionada pela mistura e compactação destes materiais. Contudo, ainda não existe uma formulação de dosagem dessa mistura baseadas em critérios mais racionais. Assim, a presente pesquisa busca fornecer subsídios para que, através do uso da relação porosidade/teor volumétrico de cal obtidas a partir da identificação e quantificação das variáveis mais importantes no controle da resistência da mistura de dois resíduos, possa determinar o seu comportamento. Isto é, a formulação de equações para previsão da resistência à compressão simples do material cimentado em cura acelerada. Para isso, foram realizados ensaios de compressão simples em corpos-de-prova com 5, 10 e 15% de cal, com peso específico aparente seco de 11, 12 e 13 kN/m³; curados por 1, 3 e 7 dias em câmara vaporizadora nas temperaturas 40, 60 e 80°C; e 3, 7 e 14 dias para cura sem vapor a 23°C. Os resultados demonstram que o aumento da quantidade de cal, do peso específico aparente seco, do tempo de cura e da temperatura provoca o aumento da resistência à compressão simples da mistura compactada. Entretanto, a temperatura apresentou um limite de influência para 3 e 7 dias, onde a variação de 60°C para 80°C não aumentou a resistência. A relação porosidade(/teor volumétrico de cal (Lv), ajustado por um expoente [/(Lv)0,11], mostrou-se adequado na formulação de equações na previsão da resistência do material cimentado para todas as temperaturas e tempos de cura estudadas. Além disso, a existência de relações únicas e distintas no controle da resistência à compressão simples em função da porosidade, teor volumétrico de cal e temperatura, assim como para o tempo de cura mostraram-se úteis para formulações de dosagem. Os resultados foram submetidos à análise de variância que comprovou que todos os fatores controláveis escolhidos para o experimento são significativos, assim como todas as interações entre eles. / The environmental issue is becoming a recurring theme in national and international forums, currently inserted in the public opinion, communities and being guiding the generation of new products and services in the industrial and commercial area focused to sustainability. In this sense, the construction industry is a major cause of environmental impact, it consumes considerable natural resources and generates large amounts of waste. Thus, the use of waste as a raw material in the construction industry provides economic and environmental benefits. Looking for progress in this discussion, this research sought to insert two wastes (fly ash and carbide lime), generated in the metropolitan region of Porto Alegre, as a possibility for solution of Engineering. For this, a study of its mechanical behavior due to cementation and compaction provided by the mixture of these materials is necessary. However there is not a rational dosage formulation of this mixture. Therefore, this research seeks to provide subsidy to determine behavior through the use of the relation of porosity/volumetric lime content obtained from the identification and quantification of the most important variables in the controlling of strength to the mixture of two residues. That is, the formulation of equations for predicting the compressive strength of cemented material into accelerated healing. For this, tests were conducted on samples with 5, 10 and 15% of lime; with dry unit weight of 11, 12 and 13 kN/m³; for 1, 3 and 7 curing days with steam in the temperature of 40, 60 and 80°C; and 3, 7 and 14 days without steam for 23°C. The results show that increasing the amount of carbide lime, dry unit weight, curing time and temperature has as consequence the increase of unconfined compression strength of the compacted mixture. However, the temperature had a limit of influence for 3 and 7 days, where the range of 60°C to 80°C did not increase the unconfined compression strength. The porosity()/volumetric lime content (Lv) ratio adjusted by an exponent [/(Lv)0,11], proved to be adequate to formulate equations to predict the strength of the cemented material for all temperatures and curing times studied. Furthermore, the existence of unique and distinct relationships in the control of unconfined compression strength of the mixture studied as a function of porosity, lime volumetric content, temperature, as for the cure time proved to be useful in dosage formulations. The results were subjected to analysis of variance showing that all the controllable factors chosen for the experiment are significant, as well as all interactions between them.

Made available in DSpace on 2014-10-09T12:41:55Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:16Z (GMT). No. of bitstreams: 0 / As cinzas leves e pesadas de carvão foram utilizadas na síntese das zeólitas (ZCL e ZCP) por tratamento hidrotérmico alcalino. As zeólitas modificadas de cinzas leves e pesadas (ZMSL e ZMSP) foram preparadas pela mistura de ZCL e ZCP com o surfactante brometo de hexadeciltrimetilamônio. Os adsorventes foram caracterizados por diferentes técnicas, tais como: métodos físico-químicos, fluorescência de raios-X, espectroscopia na região do infravermelho, difração de raios-X e microscopia eletrônica de varredura. O processo de adsorção dos corantes cristal violeta (CV) e do ácido laranja 8 (AL8) foi realizado em sistema de batelada com o objetivo de investigar o equilíbrio e a dinâmica dos materiais zeolíticos no tratamento de efluentes. Os modelos de cinética de pseudo-primeira-ordem e pseudo-segunda-ordem foram aplicados aos dados experimentais e a cinética de pseudo-segunda-ordem descreveu a adsorção dos corantes sobre os adsorventes. Estudos da difusão intrapartícula revelaram que as velocidades de adsorção não eram controladas somente pela etapa de difusão. O modelo de Freundlich ajustou-se melhor aos dados experimentais para todos os sistemas estudados, com exceção do sistema CV/ZCL, que seguiu o modelo de Langmuir. As capacidades máximas de adsorção das zeólitas modificadas foram maiores do que aquelas obtidas para as zeólitas não modificadas. Este melhor desempenho é devido ao ambiente hidrofóbico proporcionado pela adsorção do surfactante catiônico na superfície do adsorvente. Os parâmetros das isotermas de adsorção foram usados para prever o design do equipamento para a realização de processo de adsorção descontínuo de estágio simples. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-12-10T17:52:55Z No. of bitstreams: 0 / Made available in DSpace on 2015-12-10T17:52:55Z (GMT). No. of bitstreams: 0 / Zeólitas sintetizadas a partir de cinzas leves e pesadas de carvão e modificadas com hexadeciltrimetilamônio (HDTMA) foram usadas como adsorvente para remoção dos corantes Solophenyl Navy (SN) e Solophenyl Turquesa (ST) e suas formas hidrolisadas, Solophenyl Navy hidrolisada (SNH) e Solophenyl Turquesa hidrolisada (STH), de efluente simulado de indústria têxtil. As zeólitas leve modificada (ZLM) e pesada modificada (ZPM) foram caracterizadas por diferentes técnicas, tais como, espectrometria de fluorescência de raios-X, difração de raios-X e microscopia eletrônica de varredura. As ZLM e ZPM apresentaram carga estrutural negativa devido à formação de uma bicamada parcial de HDTMA na superfície externa da zeólita. A concentração inicial dos corantes, o tempo de contato e o equilíbrio de adsorção foram avaliados. A cinética de adsorção de SN, ST, SNH e STH sobre as zeólitas seguiu o modelo de pseudo segunda- ordem. O tempo de equilíbrio foi de 20 min para SN e ST e 30 min para SNH e STH sobre ZLM, enquanto sobre ZPM foi de 60 min para SN e ST e 20 e 30 min para SNH e STH, respectivamente. Os modelos de Langmuir, Freundlich e Temkin foram aplicados para descrever as isotermas de adsorção. A adsorção dos corantes foi melhor descrita pelo modelo de Langmuir, com exceção dos sistemas SN/ZPM, SNH/ZPM e SNH/ZLM que seguiram modelo de Freundlich. As capacidades máximas de adsorção foram 3,64; 3,57; 2,91 e 4,93 mgL-1 para SN, ST, SNH e STH pela ZLM, respectivamente e 0,235; 0,492; 1,26 e 1,86 mgL-1 pela ZPM, nesta mesma ordem. O melhor desempenho dos corantes hidrolisados foi atribuído à redução do tamanho das moléculas dos corantes durante o processo de hidrólise. A toxicidade aguda dos corantes foi avaliada por diferentes organismos teste. O microcrustáceo C. dubia apresentou valores de EC50 de 1,25; 54,5; 0,78 e 2,56 mgL-1 para SN, ST, SNH e STH, respectivamente. A macrófita L. minor mostrou valores de EC50 de 18,9; 69,4; 10,9 e 70,9 mgL-1 para SN, ST, SNH e STH, respectivamente. As larvas de mosquitos C. tepperi mostraram valores de EC50 de 119 e 440 mgL-1 para a SN e ST, respectivamente. Com relação ao processo de adsorção, os efeitos agudos foram substancialmente reduzidos após o tratamento da solução aquosa de SN e ST com ZLM, assim como de suas formas hidrolisadas, apresentando nenhuma toxicidade após a remoção de 100% da cor. Após o tratamento dos corantes com ZPM houve um aumento da toxicidade, com exceção dos corantes SNH e STH que não apresentaram toxicidade após o tratamento. Testes de Avaliação e Identificação da Toxicidade foram realizados a fim de identificar quais substâncias estariam causando a toxicidade nos corantes SN, ST e no lixiviado de ZLM e ZPM. Os efeitos tóxicos foram reduzidos significativamente após a manipulação com Extração de Fase Sólida (SPE) e ácido etilenodiaminotetracético (EDTA) para o lixiviado de ZLM e ZPM. Os corantes mostraram redução na toxicidade após a manipulação com EDTA indicando que as substâncias tóxicas eram principalmente metais catiônicos. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Waldir Antonio Bizzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T20:40:56Z (GMT). No. of bitstreams: 1 FrancoJacome_DiegoLuis_M.pdf: 6974773 bytes, checksum: 66b68efde995c3ab7c55a3d28e15cc19 (MD5) Previous issue date: 2014 / Resumo: A cadeia produtiva da cana-de-açúcar tem focado grande interesse no aproveitamento integral dos seus principais subprodutos: a palha e o bagaço (sendo a palha constituída das porções foliares e ponteiras da cana-de-açúcar). Isto tem sido feito através da mudança das rotas produtivas, onde o bagaço será utilizado para a produção de etanol de segunda geração e a palha como substituta do bagaço nas caldeiras de geração de vapor. Atualmente a palha não está consolidada como combustível e, portanto, seu comportamento nos geradores de vapor permanece desconhecido. Sabendo que as incrustações devido à fusão das cinzas durante a combustão de combustíveis sólidos representa um dos maiores problemas na operação dos equipamentos de geração de vapor, neste trabalho, foi caracterizada a palha de cana como combustível a fim de prever seu possível comportamento em caldeiras industriais. Amostras de palha de cana-de-açúcar foram recolhidas em duas condições: diretamente da planta e recolhida no solo após a colheita mecanizada. Foram estudados e analisados os comportamentos das cinzas da palha integral e seus componentes (pontas, folhas verdes e folhas secas), por meio das técnicas de análise térmica simultânea (STA) e da espectrometria de energia dispersiva (EDS). Desta forma, foram identificadas temperaturas de evaporação e a composição dos principais constituintes voláteis das cinzas, representados por uma reação endotérmica com perda de massa. Igualmente, a temperatura de fusão foi detectada como reação endotérmica sem envolver perdas de massa. As análises apresentaram composição e comportamentos diferentes para cada um dos componentes da palha baseados principalmente no teor de metais álcali, cloro e das temperaturas de preparação das cinzas prévias às análises. Neste sentido, as porções correspondentes às pontas e folha verdes da cana-de-açúcar, apresentaram impactos relacionados com incrustações (fouling/slagging) superiores às de folhas secas e palha integral. Baseados nos resultados obtidos a palha de cana-de-açúcar perfila-se como uma possível biomassa substituta ao bagaço nas caldeiras de geração industriais / Abstract: The sugarcane supply chain has lately placed great interest on the comprehensive use of its main by-products: straw and bagasse (the straw constituted by leaves and tops). By changing the production routes, sugarcane bagasse will be used as an energy source for the production of second generation ethanol and straw will substitute bagasse in steam generators. However, sugarcane straw is not currently used as fuel; therefore, its behavior in industrial boilers remains unknown. Slagging and fouling depositions due to fly ash melting within the boiler during combustion of solid fuel represents one of the most significant issues in the operation and maintenance of steam generation equipment. The main objective of this work was to characterize sugarcane straw as a fuel in order to predict its performance in industrial boilers. Samples of straw were collected in two different conditions: directly from the plant and off the field after mechanized harvest. The behavior of the ashes produced at different temperatures (575°C, 785°C and 985/950/850°C) from the integral sugarcane straw and its individual components (tops, dry leaves and green leaves) were analyzed by simultaneous thermal analysis (STA) and energy dispersive spectroscopy (EDS). Evaporation temperature and composition of the main volatile constituents of ashes formed, represented by an endothermic reaction involving changes in mass were identified. Also, fusion temperature was determined to be an endothermic reaction without mass loss. Results showed different elemental compositions and behaviors of ashes for each constituent of sugarcane straw, mainly based on alkali and chlorine percentage, and ashing temperature. In this regard, the fractions corresponding to sugarcane tops and green leaves showed major impacts on slagging and fouling depositions compared to dry leaves and raw straw fraction possibly due to its high levels of potassium and chlorine. Based on the results obtained from this research, sugarcane straw is profiled as an excellent substitute biomass for bagasse in industrial steam generation boilers, instead of being burned as a pre-harvest technique / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

Les déchets solides générés par notre société sont nombreux. Les cendres volantes sont des déchets solides produits lors de la combustion de déchets domestiques ou industriels dans des incinérateurs. Les cendres volantes sont également produites par la combustion du charbon dans les centrales à charbon. Les cendres volantes sont des résultats de ces combustions et représentent importante quantité de déchets produits chaque année par notre société. Les possibilités de recyclage de ces déchets sont nombreuses : dans la construction, l'industrie routière. Elles sont également stockées pour une utilisation ultérieure. Les origines différentes des charbons et déchets incinérés conduisent à une minéralogie et une composition élémentaire complexe. En tant que sous-produit le devenir des cendres volantes est important à déterminer, aussi la détermination de la composition élémentaire de ces cendres volantes est-elle indispensable.Les méthodes classiques de préparation des échantillons solides sont la minéralisation acide ou la fusion alcaline. Ces procédures prennent du temps et supposent l’utilisation de réactif, de plus la digestion complète n'est pas toujours assurée. Le risque de contamination par les réactifs employés est important au cours de ces méthodes classiques de préparation. Au cours de la dernière décennie, le développement d’analyse directe d'échantillons solides en utilisant des méthodes d'ablation laser a été important en raison de la nécessité de réduire le temps d'analyse et de réduire aussi la consommation de réactifs. Dans ce travail, deux méthodes basées sur l'ablation par laser seront étudiées pour l'analyse des cendres: Laser Induced Breakdown Spectroscopy (LIBS) et Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). La spectrométrie LIBS sera étudiée pour la détermination quantitative des éléments majeurs dans les échantillons de cendres alors que le couplage ablation laser ICP / MS sera employé pour détermination des éléments traces. L'optimisation de la sensibilité et les stratégies d'étalonnage sont les principaux problèmes traités dans ce travail. La préparation des échantillons et l’optimisation ont été effectuées pour déterminer les éléments tels que Al, As, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Sr, V et Zn par les deux méthodes.Les performances analytiques telles que les limites de détection, justesse ont été obtenus à la suite d'optimisations appropriées des liants et de la sélection de l’étalon interne approprié. En conclusion, l’analyse directe de solides en utilisant les techniques basées sur l’ablation laser développées dans ce travail conduisent à une justesse acceptable pour la détermination des éléments majeurs et traces dans les cendres volantes / Solid waste generated by our society are numerous, fly ashes are produced during the combustion of domestic or industrial waste in incinerators. Fly ashes are also produced through coal combustion in coal fired power plants. Fly ashes are results of these combustions and represent important quantity of waste produced every year by our society. They have variable use – in construction, road industry, or they can be stocked for further use. As they are result of different origin, they have complex mineral and elemental composition. As a by-product or as a recycled product fly ashes fate is important to determine. In this view the determination of the elemental composition of fly ashes is the aim of this work.Conventional methods of sample preparation are acid digestion or alkali fusion. These procedures are time and reagent consuming and complete digestion is not assured. The potential contamination of the reagents employed is important during these classical sample preparation methods. During the past decade, development of direct solid sampling using laser ablation methods was important due to the need of reducing analysis time and also reducing reagent consumption. In this work, two methods based on laser ablation will be studied for fly ash analysis: Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). LIBS will be studied for quantitative determination of major elements in fly ash samples while Laser ablation / ICP MS will be employed for trace element determination.The sensitivity optimization and different calibration strategies are key problems of laser sampling methods. Sample preparation and condition optimisation were performed to determine major, minor and trace elements such as Al, As, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Sr, V and Zn by both methods – LIBS for major elements and LA-ICP-MS for minor and trace elements.Analytical properties such as detection limits, accuracy and analytical working curves were obtained following suitable optimisation of binders and internal standards. Compromise binder and analytical conditions were selected to determine the elements in fly ash samples.In conclusion, direct solid sampling using laser ablation followed by LIBS or for solid introduction into ICP was found to determine major, minor and trace elements in fly ashes, improving pellets mechanical stability, high samples sensitivity and acceptable accuracy and detection limits.

In Sweden, there are limits to how much leachable substances waste must contain in order to be deposited as hazardous waste. Fly ash from waste incineration often end up over the limit, mainly due to the chloride content. Fly ash is therefore often deposited abroad. The purpose of this study was to investigate the possibility to handle fly ash locally. To clarify how the law is applied, environmental reports and permit documents from ten waste sites with permission to deposit fly ash were studied. In addition, a literature study was made to review the state of knowledge regarding the treatments of fly ash. The treatment methods are numerous, but are at different levels of commerciality. Among the treatments available there are both physical, chemical, biological, electrical and thermal variants. Many of the treatments (except for carbonation and microbial bioleaching) results in chloride levels below the limits. Several are however unrealistically expensive or generate wastewater with high levels of chloride that would need further treatment. Three plants out of the ten holding permits to deposit fly ash, have exemptions from the limit for chlorides. It's however difficult to see a common reasoning for allowing exemptions. In several cases there are sensitive receiving waters downstream from the landfill. One reason to be dispensed despite this sensitivity, may be the guidance that EPA issued. It is not formulated any specific concerns relating to chlorides. One handles therefore often high levels of chloride in the leachate as a dilution problem, not a leaching problem. / I Sverige finns det gränsvärden för hur mycket utlakningsbara ämnen avfall får innehålla för att kunna deponeras som farligt avfall. Flygaska från avfallsförbränning hamnar ofta över gränsen för vad som får deponeras, främst p.g.a. kloridinnehållet, och askan deponeras därför bl.a. i Norge och Tyskland. Syftet med denna studie var att utreda möjligheten att hantera flygaska lokalt. För att klargöra hur lagstiftningen tillämpas har miljörapporter och tillståndsbeslut från tio avfallsanläggningar med tillstånd att deponera flygaska studerats. Dessutom har en litteraturstudie gjorts av kunskapsläget när det gäller behandling av flygaska för att motverka lakning av klorider. Behandlingsmetoderna är många, men har kommit olika långt i att anses som kommersiella. Bland behandlingarna finns både fysiska, kemiska, biologiska, elektriska och termiska varianter. Många av behandlingarna (med undantag för karbonatisering och mikrobiell bioutlakning) gör att gränsvärden för utlakning av klorider klaras. Många av behandlingarna är dock orealistiskt dyra eller genererar avloppsvatten med höga kloridhalter. Av de tio anläggningar som innehar tillstånd till att deponera flygaska, så har tre även dispens för gränsvärdet för klorider. Utifrån den information som finns i tillståndsbesluten är det mycket svårt att se ett mönster vad gäller bedömningen av de enskilda fallen. I flera fall finns känsliga recipienter nedströms deponin. En anledning till att dispens ges trots denna känslighet kan vara den vägledning som Naturvårdsverket gett ut. Där formuleras inte någon specifik problematik kring klorider, utan andra ämnen är i fokus. Man behandlar därför ofta höga kloridhalter i lakvatten som ett utspädningsproblem, istället för ett utlakningsproblem.

The aim of this master thesis is study of possibilities of processing energy by-products, especially coal fly ash and fluidized bed ash, by hydrothermal treatment. Thanks to hydrothermal conditions and proper alkali activation of ashes we can obtain zeolites. Zeolites are microporous crystalline aluminosilicates which are use in many industrial sectors as catalysts, adsorbents and very good ion exchangers. The results of hydrothermal synthesis are influenced by many variable factors. This thesis mainly focused on influence of chosen alkali activator and the concentration of the activator together with a temperature of hydrothermal process. Other factor that is studied is choice of starting materials and solution/ash ratio. Phase composition of prepared samples was characterized by XRD and scanning electron microscopy (SEM). Also cation exchange capacity of prepared samples was determined.

Incineration is a mainstream strategy for solid waste management in Sweden and all over the world. Improved knowledge and understanding about the distribution of trace elements (in ashes) during incineration, and how trace element partitioning respond to the changes in waste composition, are important in terms of combustion process optimization and plant efficiency. Moreover, determination of chemical association of trace elements in ashes are vital for avoiding environmental concerns and to promote possible reuse. In this study, partitioning of trace elements in ashes during incineration as function of input waste fuel and incineration technology was investigated. Further, chemical association of trace elements in resulting ashes was studied. An evaluation was also performed about feasibility of metal extraction from sulfidic mining waste and flotation tailings. Moreover, green liquor dreg (GLD) was tested with respect to stabilization of metals within the sulfidic mining waste. Findings showed that the total input of trace elements and chlorine affects the partitioning and increasing chlorine in the input waste caused increase in transfer of trace elements to fly ash especially for lead and zinc. Vaporization, condensation on fly ash particles and adsorption mechanisms play an important role for metal distribution. Firing mixed waste, especially biofuel mix, in grate or fluidized (CFB) boilers caused increased transfer into fly ash for almost all trace elements particularly lead and zinc. Possible reasons might be either an increased input concentration of respective element in the waste fuel, or a change in volatilization behavior due to the addition of certain waste fractions. Chemical association study for fly ashes indicated that overall, Cd, Pb, Zn, Cu and Sb are presenting major risk in most of the fly ashes, while in bottom ashes, most of elements are associated with stable fraction. Further, fuel type affects the association of elements in ashes. Chemical leaching of mining waste materials showed that sulfuric acid (under different conditions) is the best reagent to recover zinc and copper from sulfidic mining waste and also copper from flotation tailings. GLD indicates potential for metal stabilization in mining waste by reducing the metal mobility. Extraction methods could be applied to treat mining waste in order to meet the regulatory level at a specific mining site.Similarly stabilization/solidification  methods might be applied after leaching for recovery of metals.

Waste rocks (WRs) from coal mining and fly ash (FA) from coal combustion were studied to determine the potential of the WRs to generate AMD, FAs to neutralise it and estimate their impacts on environment. The ultimate goal was to develop a methodology based on co-disposal to mitigate the environmental problems associated to both wastes. Two methods for co-disposal were tested: i) Mixing WRs and FAs and ii) covering WRs with FAs. WRs were sampled from the Lakhra coal mines in Pakistan (PK), which has an estimated coal reserves of 1.3 Btonne, varying from lignite to sub-bituminous quality. The FA was sampled from a power plant utilising coal from Lakhra coal mines and is situated in close vicinity (15km) of the mine site. For comparative purposes a bituminous FA from Finland (FI) and biomass FA from Sweden (SE) were also characterised. The WRs and FA samples were characterised by mineralogical and geochemical methods. Besides organic material (coal traces), quartz, pyrite, kaolinite, hematite, gypsum and traces of calcite, lime, malladerite, spangolite, franklinite and birnessite were identified in WRs by XRD. The major elements Si, Al, Ca and Fe were in the range (wt. %) of 8 – 12, 6 – 9, 0.3 – 3 and 1 – 10, respectively, with high S concentrations (1.94 – 11.33 wt. %) in WRs. The AMD potential of WRs ranged from -70 to -492 kg CaCO3 tonne-1. All FAs contained quartz, with iron oxide, anhydrite and magnesioferrite in PK, mullite and lime in FI and calcite and anorthite in SE. The Ca content in SE was 6 and 8 times higher compared to PK and FI, respectively. FAs were enriched in As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn compared to continental crust. The acid neutralising potential of PK was equivalent to 20 kg CaCO3 tonne-1 compared to 275 kg CaCO3 tonne-1 (SE) and 25 kg CaCO3 tonne-1 (FI). During the period of 192 days in weathering cell experiments (WCE), the pH of leachates from most acidic WRs was maintained from 1 to 2.5, whereas, the less acidic WRs produced leachates of mildly acidic (2.7) to neutral (7.3) pH. The leachates from very acidic WRs ranged in the concentrations of Fe, SO24− and Al from mg L-1 to g L-1. The samples were subjected to column leaching experiments (CLE) in which mixture (FA:WR; 1:3) and cover (FA:WR; 1:5) cases were mimicked (with 10mm particle size) and effects of particle size (2, 5 and 10mm) on element leaching were studied. Despite having the lowest acid-neutralisation potential compared to FI and SE, co-disposal of PKFA as mixture readily provides acid buffering minerals, resulting in better start-up pH conditions and leachate quality. However, acidity produced by secondary mineralisation contributes towards the acidification of the system, causing stabilisation of pH at around 4.5−5. Secondary mineralisation (especially Fe- and Al-mineral precipitation) also removes toxic elements such as As, Pb, Cu, Zn, Cd, Co, Ni and Mn, and these secondary minerals can also buffer acidity when the pH tends to be acidic. In contrast, the pH of the leachates from the PKFA cover scenario gradually increased from strongly acidic to mildly acidic and circumneutral along with decrease in EC and elemental leaching in different WRs. Gradually increasing pH can be attributed to the cover effect, which reduces oxygen ingress, thus sulphide oxidation, causing pH to elevate. Due to the fact that pH~4–5 is sufficient for secondary Fe- and Al-mineral precipitation which also removes toxic elements (such as Cd, Co, Cu, Zn and Ni) by adsorption and/or co-precipitation, the FA cover performs well enough to achieve that pH until the conclusion of the CLE. However, due to the slower reactivity of the buffering system (additional to the initial flush-out), leaching in the beginning could not be restricted. The co-disposal of FA as cover and/or mixture possesses potential for neutralisation of AMD and improving leachate quality significantly. Particle size of the WRs affected the leaching of the sulphide related elements (such as Fe, S, Zn, Co, Cr, Cu, Mn and Ni) in CLE and WCE. Experiments with ≤1mm particle size constantly produced acidic and metal laden leachates. Co-disposal of FA and WRs as cover and mixture need to be investigated on pilot-scales before full-scale application.