O uso de carvão mineral como fonte energética tem como consequência a geração de cinzas volantes, que é atualmente um dos resíduos mais gerados no Brasil. A primeira fase deste estudo consistiu em aplicar diferentes cinzas volantes de carvão provenientes de usinas termelétricas brasileiras na síntese de material zeolítico usando tratamento hidrotérmico clássico bem como caracterizar físico-quimicamente os produtos e as matérias primas. O conteúdo dos principais compostos formadores de estruturas de zeólitas, SiO2 e Al2O3, correspondeu acima de 70% para todas as amostras de cinzas. As cinzas apresentaram composição mineralógica similar com a presença de quartzo, mulita, hematita e magnetita. O tipo de zeólita formado por tratamento hidrotérmico variou em geral com a composição química das cinzas precursoras. Zeólitas NaP1 foram possíveis de serem sintetizadas somente usando-se matérias primas com baixo teor de ferro e cálcio. A zeólita X, por sua vez, foi obtida a partir de amostras com elevados teores de alumínio. Os valores de capacidade de troca catiônica (CTC) das zeólitas foram maiores do que os valores encontrados para as cinzas devido à elevada área específica e menor relação SiO2/Al2O3. Na segunda fase do estudo, zeólitas A e X com grau de pureza entre 88 e 100%, respectivamente, foram sintetizadas pelo método de duas etapas com fusão prévia utilizando-se dois tipos de cinzas de carvão brasileiras com diferentes composições químicas e sem tratamento prévio. Não foram utilizadas sementes ou agentes direcionadores de estrutura durante a síntese. Um roteiro geral para a síntese de zeólitas A e X com elevado grau de pureza foi elaborado baseando-se nos estudos relatados na segunda fase deste estudo. Verificou-se por meio dos estudos de composição mineralógica e morfologia que o método de duas etapas com fusão prévia das cinzas é responsável pela síntese de materiais mais puros e uniformes quando comparados aos materiais sintetizados pelo tratamento hidrotérmico clássico. Os valores da relação Si/Al molar calculados para todas as zeólitas com elevado grau de pureza foram próximos aos valores teóricos presentes em literatura e seus valores de CTC representaram um aumento de 1,9 a 3,0 vezes com relação às zeólitas sintetizadas pelo tratamento hidrotérmico clássico. Um estudo da possibilidade de reaproveitamento da solução remanescente de síntese hidrotérmica clássica foi realizado. Os materiais zeolíticos resultantes apresentaram misturas de fases de zeólitas A, X e Sodalita. O projeto de uma planta em escala piloto para a produção de material zeolítico usando cinzas de carvão como matéria prima contendo a descrição do processo e a lista de equipamentos e materiais básicos é também apresentado na tese. Este projeto poderá servir de base para as usinas termelétricas a carvão que desejam agregar valor às cinzas volantes produzidas em grande escala. / The use of coal as an energetic source has as a consequence the fly ash generation, which is currently one of the wastes generated in greater quantities in Brazil. The first step of this study was to apply different coal fly ashes from Brazilian thermal power plants for the synthesis of zeolitic materials using a classic hydrothermal treatment as well as to characterize the physical and chemical properties of the products and the raw materials. The contents of the main compounds which are responsible for the zeolitic structure formation, SiO2 and Al2O3, corresponded above 70 wt.% for all fly ash samples. The ashes presented a similar mineralogical composition with the presence of quartz, mullite, hematite and magnetite. The kind of zeolite formed by the hydrothermal treatment varied depending on the chemical composition of fly ash. NaP1 zeolite was formed only using fly ashes samples with low content of iron and calcium. X zeolites was synthesized using fly ashes with high content of aluminium. Cation exchange capacity (CEC) values for the zeolitic materials were higher than those of fly ash due to their higher specific surface area and lower SiO2/Al2O3 ratio. In the second stage of this study, A and X zeolites with a purity between 88 and 100%, respectively, were synthesized using the two-step method with a fusion step using two kinds of Brazilian coal ashes with different chemical compositions and without pre-treatment. No seeds or structure-directing agents were used in the synthesis. A general route for the synthesis of A and X zeolites with high purity was developed based on the studies reported in the second stage of this study. It has been found through mineralogical composition and morphology studies that the two-step method with a fusion step of the ash is responsible for the synthesis of more pure and uniform materials when compared to materials synthesized by conventional hydrothermal treatment. The Si/Al molar ratios values calculated for all high purity zeolites were close to the theoretical values found in the literature and their CEC values were 1.9 - 3.0 times higher than those of the zeolites synthesized by classic hydrothermal treatment. A study of the reuse of the residue solution in classic hydrothermal synthesis was also performed. The resulting zeolitic materials presented mixtures of A, X and Sodalite zeolites phases. The project design of a pilot-scale plant for the zeolitic material production using coal ash as a raw material containing the description of the process and the list of equipment and basic materials needed is also presented in the thesis. This project can provide a reference for coal-fired power plants which wish to add value to their fly ashes in large scale production.

O uso de carvão mineral como fonte energética tem como consequência a geração de cinzas volantes, que é atualmente um dos resíduos mais gerados no Brasil. A primeira fase deste estudo consistiu em aplicar diferentes cinzas volantes de carvão provenientes de usinas termelétricas brasileiras na síntese de material zeolítico usando tratamento hidrotérmico clássico bem como caracterizar físico-quimicamente os produtos e as matérias primas. O conteúdo dos principais compostos formadores de estruturas de zeólitas, SiO2 e Al2O3, correspondeu acima de 70% para todas as amostras de cinzas. As cinzas apresentaram composição mineralógica similar com a presença de quartzo, mulita, hematita e magnetita. O tipo de zeólita formado por tratamento hidrotérmico variou em geral com a composição química das cinzas precursoras. Zeólitas NaP1 foram possíveis de serem sintetizadas somente usando-se matérias primas com baixo teor de ferro e cálcio. A zeólita X, por sua vez, foi obtida a partir de amostras com elevados teores de alumínio. Os valores de capacidade de troca catiônica (CTC) das zeólitas foram maiores do que os valores encontrados para as cinzas devido à elevada área específica e menor relação SiO2/Al2O3. Na segunda fase do estudo, zeólitas A e X com grau de pureza entre 88 e 100%, respectivamente, foram sintetizadas pelo método de duas etapas com fusão prévia utilizando-se dois tipos de cinzas de carvão brasileiras com diferentes composições químicas e sem tratamento prévio. Não foram utilizadas sementes ou agentes direcionadores de estrutura durante a síntese. Um roteiro geral para a síntese de zeólitas A e X com elevado grau de pureza foi elaborado baseando-se nos estudos relatados na segunda fase deste estudo. Verificou-se por meio dos estudos de composição mineralógica e morfologia que o método de duas etapas com fusão prévia das cinzas é responsável pela síntese de materiais mais puros e uniformes quando comparados aos materiais sintetizados pelo tratamento hidrotérmico clássico. Os valores da relação Si/Al molar calculados para todas as zeólitas com elevado grau de pureza foram próximos aos valores teóricos presentes em literatura e seus valores de CTC representaram um aumento de 1,9 a 3,0 vezes com relação às zeólitas sintetizadas pelo tratamento hidrotérmico clássico. Um estudo da possibilidade de reaproveitamento da solução remanescente de síntese hidrotérmica clássica foi realizado. Os materiais zeolíticos resultantes apresentaram misturas de fases de zeólitas A, X e Sodalita. O projeto de uma planta em escala piloto para a produção de material zeolítico usando cinzas de carvão como matéria prima contendo a descrição do processo e a lista de equipamentos e materiais básicos é também apresentado na tese. Este projeto poderá servir de base para as usinas termelétricas a carvão que desejam agregar valor às cinzas volantes produzidas em grande escala. / The use of coal as an energetic source has as a consequence the fly ash generation, which is currently one of the wastes generated in greater quantities in Brazil. The first step of this study was to apply different coal fly ashes from Brazilian thermal power plants for the synthesis of zeolitic materials using a classic hydrothermal treatment as well as to characterize the physical and chemical properties of the products and the raw materials. The contents of the main compounds which are responsible for the zeolitic structure formation, SiO2 and Al2O3, corresponded above 70 wt.% for all fly ash samples. The ashes presented a similar mineralogical composition with the presence of quartz, mullite, hematite and magnetite. The kind of zeolite formed by the hydrothermal treatment varied depending on the chemical composition of fly ash. NaP1 zeolite was formed only using fly ashes samples with low content of iron and calcium. X zeolites was synthesized using fly ashes with high content of aluminium. Cation exchange capacity (CEC) values for the zeolitic materials were higher than those of fly ash due to their higher specific surface area and lower SiO2/Al2O3 ratio. In the second stage of this study, A and X zeolites with a purity between 88 and 100%, respectively, were synthesized using the two-step method with a fusion step using two kinds of Brazilian coal ashes with different chemical compositions and without pre-treatment. No seeds or structure-directing agents were used in the synthesis. A general route for the synthesis of A and X zeolites with high purity was developed based on the studies reported in the second stage of this study. It has been found through mineralogical composition and morphology studies that the two-step method with a fusion step of the ash is responsible for the synthesis of more pure and uniform materials when compared to materials synthesized by conventional hydrothermal treatment. The Si/Al molar ratios values calculated for all high purity zeolites were close to the theoretical values found in the literature and their CEC values were 1.9 - 3.0 times higher than those of the zeolites synthesized by classic hydrothermal treatment. A study of the reuse of the residue solution in classic hydrothermal synthesis was also performed. The resulting zeolitic materials presented mixtures of A, X and Sodalite zeolites phases. The project design of a pilot-scale plant for the zeolitic material production using coal ash as a raw material containing the description of the process and the list of equipment and basic materials needed is also presented in the thesis. This project can provide a reference for coal-fired power plants which wish to add value to their fly ashes in large scale production.

O presente trabalho tem como objetivo o estudo e aproveitamento de cinzas leves da queima de carvão mineral em termoelétrica, como reforço para o Compósito de Matriz Metálica de cobre. Foram estudados diferentes percentuais de cinzas leves como reforço para o cobre, sendo misturados estes pós através de m , compactando os pós em diferentes pressões e sinterizando os corpos de prova obtidos pela compactação. A amostra sinterizada que apresentou a maior dureza entre todos os corpos de prova sinterizados, atingindo 89 HV, foi utilizada como base para a formulação e obtenção de novos corpos de prova, que foram estudados sob condições de moagem dos pós por moinho de bolas e moagem de alta energia. A fabricação do compósito seguiu os padrões industriais do processo de Metalurgia do Pó, como a mistura e moagem dos pós, compactação dos pós e sinterização em atmosfera controlada. Foi realizado o estudo das propriedades físicas e elétricas do compósito formado por cobre e cinzas leves, que comprovou o aumento da dureza para 122 HV, mantendo a condutividade do cobre puro. Este trabalho proporciona uma nova aplicação para as cinzas leves, utilizando estes resíduos de usinas termoelétricas como matéria prima para reforço mecânico na composição de peças à base de cobre, na indústria metalmecânica. / This paper aims to study and use fly ash from coal-fired thermal power plant, as reinforcement for copper Metal Matrix Composite. Different fly ash percentage were studied as reinforcement for copper. The powders were mixed by "Twin V Mixer'', were compacted at different pressures and the compacted samples were sintered. The sintered sample with the highest hardness among all samples reached 89 HV and was used as basis for the formulation and obtaining of new samples, which were studied under controlled conditions of ball milling and mechanical alloying. The manufacture of the composite was made using Powder Metallurgy processes like mixing and milling of powders, compacting of the powders and sintering at controlled atmosphere. A study on the physical and electrical properties of the composite formed by copper and fly ash was carried out proving the hardness increase to 122 HV and maintaining the conductivity of pure copper. This work provides a new application for fly ash using these power plants waste as raw material for mechanical reinforcement in the composition of copper parts in the metalworking industry.

Cinzas de carvão mineral são resíduos gerados em grandes quantidades nas usinas termelétricas. Este é um dos resíduos de maior geração no Brasil, aproximadamente 1,7 milhões de toneladas por ano. A disposição muitas vezes irregular deste resíduo pode causar problemas de ordem ambiental, como contaminação de águas subterrâneas, do solo e desequilíbrio de sistemas ecológicos. Uma possibilidade de uso para estas cinzas é a síntese de zeólitas, que são minerais aluminossilicatos microporosos com propriedades interessantes para uso na indústria. Neste trabalho, estudou-se a síntese de zeólitas a partir de cinzas volantes visando à sua aplicação em dessulfuração de gases. A síntese foi realizada pelo método hidrotérmico, utilizando solução alcalina de KOH e relação solução/sólido de 2 mL g-1. As variáveis estudadas foram temperatura (100 e 150 °C), concentração da solução alcalina (3 e 5 mol L-1) e tempo de reação (8, 24, 48 e 72 h). Os produtos obtidos e as cinzas precursoras foram caracterizados quanto à composição química (FRX), mineralógica (DRX), morfológica (MEV), área específica (BET) e capacidade de troca catiônica (CTC). A partir da determinação das estruturas cristalinas (DRX) foi possível identificar a formação das zeólitas merlinoíta e perlialita em algumas das condições investigadas. O maior valor de área específica BET foi de 102,42 m2 g-1, nas condições de síntese de 150 °C, 5 mol L-1 e 72 h, representando um aumento de 30 vezes em relação à área das cinzas. Os valores de capacidade de troca catiônica ficaram entre 0,71 e 2,02 meq NH4+ g-1 para as diferentes condições estudadas. Com as amostras que apresentaram os melhores resultados nas caracterizações foram realizados testes de dessulfuração e seu desempenho foi comparado com as cinzas precursoras, carvão ativado e zeólita comercial. Foram construídas curvas de ruptura e isotermas de adsorção para esses sistemas. As zeólitas sintetizadas a partir das cinzas apresentaram maiores valores de adsorção máxima. A zeólita que apresentou melhor resultado de adsorção foi a sintetizada nas condições de 150 °C, 5 mol L-1 e 72 h de tempo de reação, sendo esta também a que apresentou maior valor de área específica. Sendo assim, a síntese de zeólitas a partir de cinzas de carvão, geradas no próprio processo de combustão em usinas térmicas, mostra-se como uma potencial aplicação no sentido de que estas podem ser utilizadas na própria usina para adsorção do SO2 gerado durante a combustão. / Coal ash is a waste generated in large quantities in the power plants. This is one of the wastes generated in larger quantities in Brazil, approximately 1.7 million tons per year. The often irregular disposal of this waste can cause environmental problems, such as contamination of groundwater, soil and imbalance of ecological systems. One possibility for using ashes is the synthesis of zeolites, which are microporous aluminosilicate minerals with interesting properties for use in industry. In this work, the synthesis of zeolites from fly ash was studied, aiming its application for gas desulfurization. The synthesis was performed by the hydrothermal method using an alkaline solution of KOH and a solution/solid ratio of 2 mL g-1. The variables temperature (100 and 150 °C), alkaline solution concentration (3 and 5 mol L-1) and reaction time (8, 24, 48 and 72 hours) were studied. The products obtained and the precursory ashes were characterized by its chemical composition (FRX), mineralogical (XRD), morphological (SEM), specific surface area (BET) and cation exchange capacity (CEC). From the determination of the crystalline structures (XRD) it was possible to identify the formation of the merlinoite and perlialite zeolites for some of the investigated conditions. The highest BET surface area was 102.42 m2 g-1 under the synthesis conditions of 150 °C, 5 mol L-1 and 72 hours. This value represented an increase of 30 times in the surface area comparing to the ash. The cation exchange capacity values varied between 0.71 and 2.02 meq NH4+ g-1 for the different conditions studied. Desulfurization tests were carried out for the samples that showed the best characterization results and its performance was compared with the precursor ash, activated carbon and commercial zeolite. Rupture curves and adsorption isotherms were constructed for these systems. The zeolites synthesized from ash showed higher values of maximum adsorption. The zeolite that showed the best adsorption result was synthesized at the conditions of 150 °C, 5 mol L-1 and 72 hours of reaction time, which also had the highest surface area value. Thus, the synthesis of zeolites from coal ash, generated in the combustion process in thermal plants, is shown as a potential application in the sense that these can be used in the plant to adsorb SO2 generated during combustion.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Includes bibliographical references. / by Jeffrey C. Alexander. / Ph.D.

As indústrias lançam diversos poluentes no meio ambiente. Dentre os poluentes destacam-se os elementos tóxicos presentes em efluentes líquidos por acarretarem alto risco potencial à saúde humana e ao meio ambiente. Os efluentes podem ser tratados por materiais adsorventes, os quais podem ser provindos de resíduos industriais. Uma forma de contribuir significativamente na sustentabilidade de uma indústria é a transformação de um de seus resíduos em sub-produto de valor agregado para aplicação no tratamento de seus efluentes líquidos como adsorvente de baixo custo. O objetivo deste trabalho foi sintetizar, e caracterizar zeólitas de cinzas de carvão e avaliar sua aplicação como material adsorvente no tratamento de efluente. Os materiais zeolíticos derivados de três tipos diferentes de cinzas de carvão (cinzas manga, cinzas ciclone e cinzas pesadas) geradas na usina termelétrica de Figueira-PR foram usados para tratar o lixiviado do aterro de cinzas de carvão da mesma usina. As seguintes características das zeólitas foram determinadas: composição mineralógica, composição química, teor de carbono total, análise morfológica, área superficial específica, capacidade de troca catiônica (CTC), perda ao fogo, pH, condutividade e densidade aparente. A fase zeolítica formada foi do tipo sodalita com as três amostras usadas como matéria prima após ativação hidrotérmica alcalina. O material zeolítico de cinzas manga apresentou a menor relação SiO2/Al2O3 (1,46), maior CTC (2,36 meq g-1) e área superficial específica (69,5 m2 g-1) e, consequentemente, maior capacidade de remoção dos íons do efluente. As concentrações de As e Cr estavam acima do padrão de lançamento de efluentes. As três amostras de materiais zeolíticos apresentaram uma remoção significativa de Ni, Cd, Zn e Co na dose de 10 g.L-1. Os materiais zeolíticos das cinzas manga e ciclone foram eficientes para reduzir a concentração de As abaixo do limite imposto pela legislação, enquanto a remoção do Cr não foi efetiva com nenhum dos materiais. Na segunda etapa do trabalho, as zeólitas foram modificadas com o surfactante brometo de hexadeciltrimetilamônio (HTDMA-Br) em concentrações de 1,8 e 20 mmol L-1. A modificação das zeólitas não melhorou a eficiência de remoção do As. A remoção do Cr usando a amostra de zeólita de cinzas manga modificada com HDTMA-Br 20 mmol L-1 resultou em uma concentração final muito próxima ao limite permitido pela legislação. / The industries release various types of pollutants into to the environment. Among these pollutants are the liquid effluents containing toxic elements, they carry a high potential risk to human health and the environment. Some effluents can be treated by adsorbent materials, which can be made from industrial waste. One way to contribute significantly to the sustainability of an industry is to transform one of its residues into a value-added by-product and use in the treatment of its own liquid effluents as a low cost adsorbent. The objective of this estudy was to synthesize and characterize coal ash zeolites and evaluate their application as adsorbent material in the treatment of effluent. Zeolite materials derived from three different types of coal ash (fly ashes, cyclone ashes and heavy ashes) generated at the Figueira-PR thermoelectric plant were used to treat leachate from the coal ash landfill of the same plant. The following zeolite characteristics were determined: mineralogical composition, chemical composition, total carbon content, morphological analysis, specific surface area, cation exchange capacity (CTC), fire loss, pH, conductivity and bulk density. The zeolite phase formed with the three samples used as raw material after alkaline hydrothermal activation was sodalite. The zeolite material from fly ash had the lowest SiO2/Al2O3 ratio (1.46), higher CTC (2.36 meq g-1) and specific surface area (69.5 m2 g-1) and, consequently, greater effluent removal capacity. The As and Cr concentrations were above the effluent discharge standard. The three samples of zeolitic materials showed a significant removal of Ni, Cd, Zn and Co in the dose of 10 g L-1. The zeolite materials from fly and cyclone ash were efficient to reduce As concentrations below the limit imposed by legislation, while removal of Cr was not effective with any of the materials. In the second stage of the study, the zeolites were modified with the surfactant hexadecyltrimethylammonium bromide (HTDMA-Br) in concentrations of 1.8 and 20 mmol.L-1. The zeolite removal efficiency of As did not improve after its modification. Removal of Cr using the 20 mmol.L-1 modified HDTMA-Br modified fly ash zeolite sample resulted in a final concentration very close to the limit allowed by the legislation.

When hollow concrete masonry is used for construction in high seismic regions, structural designs typically require fully grouted walls. The grouting process is labor-intensive, time-consuming and has a high energy demand due to requirements of consolidation in each and subsequent grout lifts. Self-consolidating grout with admixtures has been successfully used without segregation in walls of up to 12.67 ft. in height. Investigation of self-consolidating grout mixes without admixtures has potential for sustainability improvement. This thesis reports on the compression strength and consolidation observations of self-consolidating characteristics of no vibration/no admixture grout made by substituting various proportions of Portland cement with Type F fly ash and/or ground granulated blast furnace slag (GGBFS). The percentages of Portland cement replacement evaluated were 0%, 50%, 60%, and 70% for Type F fly ash. The percentages of Portland cement replacement evaluated were 0%, 60%, 70% and 80% for Type F fly ash and GGBFS. Grout compressive strengths were evaluated from individually filled grout specimens constructed in concrete masonry hollow core units, dry cured, and tested after 7, 14, 28, 42, 56, and 130 days. Also, hollow concrete masonry walls were built 12.67 ft. tall and grouted. The relative performance was assessed by comparing to conventional grouted masonry and evaluating consolidation characteristics around mortar fins and reinforcement; compressive strength tests after 130 days of curing, and rebar pull-out tests were taken from various wall heights. All experimental grouts had acceptable consolidation characteristics but fly ash replacement grouts did not meet the compressive strength requirements.

The use of Portland cement in concrete construction is under critical review due to high amount of carbon dioxide gas released to the atmosphere during the production of cement. In recent years, attempts to increase the utilization of fly ash to partially replace the use of Portland cement in concrete are gathering momentum. Most of this by-product material is currently dumped in landfills, creating a threat to the environment. Geopolymer concrete is a ‘new’ material that does not need the presence of Portland cement as a binder. Instead, the source of materials such as fly ash, that are rich in Silicon (Si) and Aluminium (Al), are activated by alkaline liquids to produce the binder. Hence concrete with no Portland cement. This thesis reports the details of development of the process of making fly ash-based geopolymer concrete. Due to the lack of knowledge and know-how of making of fly ashbased geopolymer concrete in the published literature, this study adopted a rigorous trial and error process to develop the technology of making, and to identify the salient parameters affecting the properties of fresh and hardened concrete. As far as possible, the technology that is currently in use to manufacture and testing of ordinary Portland cement concrete were used. Fly ash was chosen as the basic material to be activated by the geopolimerization process to be the concrete binder, to totally replace the use of Portland cement. The binder is the only difference to the ordinary Portland cement concrete. To activate the Silicon and Aluminium content in fly ash, a combination of sodium hydroxide solution and sodium silicate solution was used. Manufacturing process comprising material preparation, mixing, placing, compaction and curing is reported in the thesis. / Napthalene-based superplasticiser was found to be ii useful to improve the workability of fresh fly ash-based geopolymer concrete, as well as the addition of extra water. The main parameters affecting the compressive strength of hardened fly ash-based geopolymer concrete are the curing temperature and curing time, the molar H2O-to-Na2O ratio, and mixing time. Fresh fly ash-based geopolymer concrete has been able to remain workable up to at least 120 minutes without any sign of setting and without any degradation in the compressive strength. Providing a rest period for fresh concrete after casting before the start of curing up to five days increased the compressive strength of hardened concrete. The elastic properties of hardened fly ash-based geopolymer concrete, i,e. the modulus of elasticity, the Poisson’s ratio, and the indirect tensile strength, are similar to those of ordinary Portland cement concrete. The stress-strain relations of fly ash-based geopolymer concrete fit well with the expression developed for ordinary Portland cement concrete.

One technology that makes concrete without cement and does not have the associated carbon footprint is geopolymer concrete. This technology utilizes waste fly ash from power stations and mixes it with activating chemicals to form a binder with similar or better properties than cement. Not only does this technology directly reduce carbon emissions by replacing cement it also utilizes the waste bi-product from power stations and prevents it from going to landfill. Concrete is composed of coarse aggregates, sand and cementitious paste. It seemed possible to make geopolymer concrete from 100% waste. The aggregates would come from recycled concrete and hard brittle bottom ash from power stations, the sand would come from foundries and the fly ash binder would also come from the same power station as the bottom ash. All of these materials are waste and would all be dumped in landfill. Where would one find all these waste materials in one place? The industrial suburb of Kwinana outside Perth is home to a large number of industries producing all these wastes. To find products that have a specification that these materials would suit was a material with a relatively low specification, one such specification is the concrete masonry units’ specification. For this to be adopted the mix design would then have to be altered to a drier type mix without any slump. As recycling facilities do not make a range of products it was decided to crush the aggregates in the laboratory specifically for this research and to blend all the waste materials. Numerous combinations were blended, analysed and assessed to establish which blends would best suit the aims and scope of this research. Eventually three blends were selected that encompassed all the waste products. / To find the right mix design proved challenging as these masonry products generally require a mix to have zero slump. It was decided to test across all the known and analysed water to geopolymer solids ratios for each of the mixes and establish the best mix based on compressive strength, workability and slump A known mix design based on research into low calcium Class F geopolymer concrete, developed at Curtin University using natural aggregates, was applied to these selected recycled waste mix designs. The benefit was to be able to compare the results of this research to a known result. Flash setting, an unknown phenomenon in geopolymer concrete, did occur in the low water mixes, but in spite of this, geopolymer concrete was successfully manufactured. The compressive strengths were substantially lower than those of the design mix and more research is required in this regard, however an indirect relationship was observed between the amount of bottom ash and the compressive strength. The high degree of LOI (loss of ignition) in both ashes, porosity of recycled aggregates, angularity, degree of fineness of the fines and flash setting are all possible factors influencing the properties of the geopolymer concrete. More research is recommended in a number of these areas to be able to understand and develop this technology further in order to make this a practical and robust technology in the quest to find solutions to our warming planet and our changing climate.

<p>The disposal of combustible wastes by incineration is a controversial issue that is strongly debated by both scientists and environmental activists due to the resulting emissions of noxious compounds, including (<i>inter alia</i>) polychlorinated dibenzo-<i>p</i>-dioxins (PCDDs), dibenzofurans (PCDFs), heavy metals and acid gases like sulfur dioxide. Currently available air pollution control devices are capable of effectively cleaning flue gases, and PCDD/F emissions to air from modern municipal solid waste (MSW) incinerators are low. However, the PCDD and PCDF end up in ash fractions that, in Sweden, are usually deposited in landfills.</p><p>The European Union has recently set a maximum permitted total concentration of 15 µg TEQ/kg for PCDD/F species in waste. Fly ash from municipal solid waste (MSW) incineration containing PCDD/Fs at concentrations above this limit will have to be remediated to avoid disposing of them in landfills; an expensive and environmentally unfriendly option. Therefore, effective, reliable and cost-effective methods for degrading PCDD/F in fly ash are required, and a better understanding of the behavior of PCDDs and PCDFs during thermal treatment will be needed to develop them.</p><p>In the studies this thesis is based upon both the formation and degradation of PCDDs and PCDFs in ashes from MSW incineration were studied.</p><p>The main findings of the investigations regarding PCCD/F formation were:</p><p>- The concentrations of PCDD and PCDF in fly ash increased with reductions in the temperature in the post-combustion zone.</p><p>- The homologue profile in the ash changed when the temperature in the post-combustion zone changed.</p><p>- The final amounts of PCDD and PCDF present were affected by their rates of both formation and degradation, and the mechanisms involved differ between PCDDs and PCDFs.</p><p>The main findings from the degradation studies were:</p><p>- The chemical composition of ash has a major impact on the degradation potential of PCDD and PCDF.</p><p>- The presence of oxygen during thermal treatment can enhance the degradation of PCDD and PCDF.</p><p>- Thermal treatment is a viable option for degrading PCDD and PCDF in ashes from MSW.</p><p>- Shifts in chlorination degree occur during thermal treatment.</p><p>- Rapid heat transfer into the ash is a key factor for ensuring fast degradation of PCDD and PCDF.</p><p>- Degradation of other chlorinated organic compounds, e.g. PCB and HCB, also occurs during thermal treatment of ash.</p><p>- Reductions in levels of PCDD and PCDF were not solely due to their desorption to the gas phase.</p><p>- Differences between the behavior of 2378-substituted congeners of PCDD and PCDF and the other congeners during thermal treatment were observed.</p><p>- Differences in isomer patterns of both PCDD and PCDF were observed between the ash and gas phases after thermal treatment at both 300 and 500 oC.</p><p>Overall, the results show that the formation and degradation mechanisms of PCDDs differ substantially from those of PCDFs. Thus these groups of compounds should be separately considered in attempts to identify ways to reduce their concentrations.</p>