<p>  </p> <p>The potential of lignocellulose for producing fermentable sugars as feedstock to manufacture fuels, chemicals, and materials for decarbonization remains untapped due to costly logistics and conversion processes. Pelleting technology offers a solution by addressing logistical issues and impacting downstream conversion, though it comes with its own costs. An overview of recent advances in pelleting technologies and their impact on bioconversion highlights the importance of understanding variables and product attributes. The interplay between pelleting and pretreatment processes, considering various feedstocks, is crucial for future design. Practical considerations such as energy consumption, costs, and environmental impacts must not be overlooked, along with exploration of cutting-edge technologies and strategies in this field. This work further presents a comprehensive investigation into the recalcitrance of pelleted corn stover to enzymatic digestion prior to any pretreatment.</p> <p>The potential of lignocellulose for producing fermentable sugars as feedstock to manufacture fuels, chemicals, and materials for decarbonization remains untapped due to costly logistics and conversion processes. Pelleting technology offers a solution by addressing logistical issues and impacting downstream conversion, though it comes with its own costs. An overview of recent advances in pelleting technologies and their impact on bioconversion highlights the importance of understanding variables and product attributes. The interplay between pelleting and pretreatment processes, considering various feedstocks, is crucial for future design. Practical considerations such as energy consumption, costs, and environmental impacts must not be overlooked, along with exploration of cutting-edge technologies and strategies in this field. </p> <p>This dissertation further presents a comprehensive investigation into the recalcitrance of pelleted corn stover to enzymatic digestion prior to any pretreatment. One aspect focuses on the role of high moisture pelleting in enhancing the enzymatic digestibility of corn stover before pretreatment, along with the relevant substrate characteristics. The pelleting process increases the digestibility of unpretreated corn stover, resulting in a glucan conversion increase from 8.2% to 15.5% at a 5% solid loading using 1 FPU Cellic® CTec2 per gram of solids. Under the same enzymatic hydrolysis conditions, the conversion of glucan remains higher for pelleted corn stover compared to its non-pelleted counterpart, even though both samples underwent identical milling processes and passed through the same screen to minimize particle impact. Compositional analysis reveals that loose and pelleted corn stover have similar non-dissolvable compositions, albeit with differences in their extractives. Using microcrystalline cellulose (Avicel) as a substrate, the presence of corn stover extractives results in a lower sugar yield compared to using citrate buffer instead, particularly for extractives from pelleted corn stover. This indicates a more negative impact of pelleted corn stover extractives on the activity of employed enzyme, CTec2. However, pelleted corn stover still shows increased overall glucan conversion compared to loose corn stover, suggesting improved digestibility of non-dissolvable components after milling and washing. The improvement in digestibility of pelleted material can be attributed to factors such as reduced particle size, enhanced substrate accessibility, and hydrolysis of cross-linking structures induced by the pelleting process. These findings offer valuable insights for the development of processing strategies aimed at sustainable and efficient utilization of lignocellulose.</p> <p>Furthermore, this dissertation delves into the profound impact of extractives on enzymatic hydrolysis, prompting a thorough examination of the composition and characteristics of extractives derived from pelleted corn stover, as well as their effects on enzymatic conversion. In contrast to previous reports, it is discovered that water extractable materials actually enhance the enzymatic hydrolysis of extractive-free stover, while the enzyme activities diminish when using microcrystalline cellulose as a substrate. This divergent behavior of extractives is attributed to the presence of lignin, which may interact with inhibitory compounds like phenolics, thereby mitigating the detrimental effects of soluble inhibitors or insoluble lignin, or both. These findings significantly advance our fundamental understanding of the intrinsic behavior of extractives and contribute to the optimization of schemes for efficient and cost-competitive enzymatic conversion of lignocellulose. </p>

Resumo: A importância dos psitacídeos como animais de estimação, o grande número de espécimes criados e os problemas desencadeados pela falta de informações sobre suas necessidades nutricionais em cativeiro, especialmente os aspectos relacionados à saúde a longo prazo das espécies com longa expectativa de vida, têm estimulado a comunidade científica ao aprofundamento sobre este tema. Os objetivos deste trabalho foram avaliar: os efeitos da inclusão de teores crescentes de fibra de cana (0, 7, 14 e 21%) sobre os coeficientes de digestibilidade aparente dos nutrientes, coeficiente de metabolização da energia bruta, energia metabolizável aparente e matéria seca das excretas; os processos de extrusão e peletização na produção de alimentos para araras; e o efeito das rações extrusadas ou peletizadas, com baixo e alto teor de fibra, sobre a ingestão de alimentos, parâmetros de bioquímica sérica e peso corporal. Foram utilizados 24 casais de Araras-Canindé. O ensaio de digestibilidade teve duração de 24 dias e adotou-se delineamento em blocos, com dois blocos de 24 unidades experimentais cada, em esquema fatorial 2 x 4 (dois tipos de processamento x quatro níveis de inclusão de fibra). O ensaio sobre os parâmetros de bioquímica sérica teve duração de 105 dias e foi utilizado delineamento inteiramente casualizado, num esquema em parcelas subdivididas, sendo as parcelas um fatorial (dois processamentos x dois níveis de inclusão de fibra x sexo das araras) e a subparcela, os resultados para o 25º e 130º dias de consumo das rações. Concluiu-se que a inclusão de fibra às rações e a diminuição da energia metabolizável resultam em redução linear na digestibilidade dos nutrientes, elevação no consumo de matéria seca e água, e redução nos níveis séricos de colesterol. Rações peletizadas demonstraramse melhores que as rações extrusadas, com menor ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The importance of parrots as pets, the growing number of specimens kept as pets and the problems caused by the lack of information about their nutritional needs in captivity, especially the aspects related to long-term health of species have a long life expectancy, has stimulated the scientific community to a depth on this topic. Our objectives were to assess: the effects of adding increasing levels of sugar cane fiber (0, 7, 14 and 21%) on apparent digestibility of nutrients, metabolism coefficient of gross energy, metabolizable energy and dry matter excreta, the processes of extrusion and pelletization to produce food for macaws and the effect of extruded or pelleted diets, with low and high fiber content on food intake, serum biochemical parameters and body weight. We used 24 pairs of blue and yellow macaw. The digestibility trial lasted 24 days and adopted block design with two blocks of 24 experimental units each in a factorial 2 x 4 (two types of processing x four levels of inclusion of fiber). The test on the parameters of serum biochemistry lasted 105 days and was used a randomized design in a split plot scheme, and the plots were a factorial (two processes x two levels of fiber x sex of macaws) and sub-plot, 25 th and 130 th days of consumption of rations. It was concluded that the inclusion of fiber in diets and the metabolizable energy decrease results in linear decrease in digestibility of nutrients, high in dry matter intake and water, and reduction in serum cholesterol. Rations proved to be better than the extruded feeds, less feed wastage and greater reduction in serum glucose and cholesterol. Diets for macaws should be based on metabolizable energy. And the reduction in energy and fat content of diets provides reduction in serum glucose, cholesterol and triglycerides, so excess energy and fat causes metabolic damage to Araras. The energy requirement ... (Complete abstract click electronic access below) / Orientador: Nilva Kazue Sakomura / Coorientador: Aulus Cavalieri Carciofi / Banca: Carlos Eduardo do Prado Saad / Banca: Manoel Garcia Neto / Banca: Euclides Braga Malheiros / Banca: José Mauricio Barbanti Duarte / Doutor

Biomass production is spatially distributed resulting in high transportation costs when moving dedicated biomass crops and crop residues. A multifaceted approach was taken to address this issue as the low bulk and energy density of biomass limits transportation efficiency. Two systems were analyzed for the conversion of biomass into a denser feedstock applicable to on-farm use. Pelletization was able to densify the material into a solid fuel. Using a pilot scale flat ring pellet mill, the density of the material was able to be increased to at least 4.4 times that of uncompressed material. Pellet durability was found to be strongly related to the moisture content of the material entering the mill. Unlike with ring roller pellet mills, a higher durability was typically seen forbiomass materials with a preconditioned moisture content of 20% (w.b.). From a liquid fuel standpoint, the conversion of lignocellulosic material into biobutanol on-farm was the second method investigated. For the pretreatment of biomass, alkaline hydrogen peroxide spray was demonstrated to be an effective enhancer of saccharification. The viability of on-farm biobutanol preprocessing bunker facilities within Kentucky was analyzed using Geographic Information systems (GIS) to specifically address transportation related factors. The spatial variability of corn field production, size, and location were resolved by utilizing ModelBuilder to combine the various forms of data and their attributes. Centralized and Distributed preprocessing with Centralized refining (DC) transportation systems were compared. Centralized was defined as transport of corn stover directly from the field to a refinery. Distributed-Centralized was specified as going from the field to the biobutanol bunker with corn stover and from the bunker to the refinery with a dewatered crude biobutanol solution. For the DC design, the location of the field and refinery were fixed with the biobutanol bunker location being variable and dependent upon differing maximum transportation (8-80 km) cutoffs for biomass transport from the field to biobutanol bunkers. The DC designs demonstrated a lower (38 - 59%) total transportation cost with a reduced fuel use and CO2 emissions compared to the centralized system.

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Agradecemos a compreensão. on 2017-01-20T15:03:30Z (GMT) / Submitted by Ludmilla Geraldo Di Santo (ludmilladisanto@gmail.com) on 2017-03-09T18:57:40Z No. of bitstreams: 1 Dissertação - Ludmilla Geraldo Di Santo.pdf: 3261093 bytes, checksum: d46f60bc493c74390b3bc14fee0f382f (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-03-20T19:30:16Z (GMT) No. of bitstreams: 1 disanto_lg_me_jabo.pdf: 3261093 bytes, checksum: d46f60bc493c74390b3bc14fee0f382f (MD5) / Made available in DSpace on 2017-03-20T19:30:16Z (GMT). No. of bitstreams: 1 disanto_lg_me_jabo.pdf: 3261093 bytes, checksum: d46f60bc493c74390b3bc14fee0f382f (MD5) Previous issue date: 2016-12-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Estudos sobre processamento de rações e sua influência no metabolismo são escassos para psitacídeos. Desta forma, o presente estudo teve como objetivo avaliar o consumo, digestibilidade, parâmetros bioquímicos, hematológicos e radiográficos de papagaios-verdadeiro após a transição de dieta com alta gordura, baseada em girassol, para alimento balanceado para manutenção de papagaios. Esta formulação balanceada foi processada de modo a se obter três diferentes graus de cozimento do amido: Ração peletizada (PEL) - ingredientes moídos com peneira de 2mm e peletizados, com 27% de cozimento do amido; Ração extrusada baixo cozimento (EXTb) - ingredientes moídos com peneira de 2mm e extrusados com baixa transferência de energia, com 82% de cozimento do amido; Ração extrusada elevado cozimento (EXTa) - ingredientes moídos com peneira de 0,5mm e extrusados com elevada transferência de energia, com 98% de cozimento do amido. Trinta papagaios-verdadeiro adultos foram mantidos na dieta à base de girassol por 90 dias, para homogeneização do grupo e determinação dos valores basais. Posteriormente foram distribuídos em delineamento inteiramente casualizado com 10 repetições (papagaios) por tratamento (rações experimentais) e mantidos nas três dietas por um período de 160 dias. Foram determinados o consumo e a palatabilidade dos alimentos, coeficiente de digestibilidade aparente dos nutrientes, concentrações de ácidos graxos voláteis - AGVs (acético, butírico, propiônico, valérico, isovalérico e isobutírico), lactato e amônia das excretas. Ao início e final do experimento foram avaliados os parâmetros hematológicos, radiográficos e as concentrações plasmáticas de aspartato aminotransferase (AST), albumina, colesterol, triglicérides, glicose e ácido úrico. Os dados foram submetidos a análise de variância e as médias comparadas pelo teste de Tukey (P<0,05). A dieta PEL apresentou maior digestibilidade da gordura e do amido que a EXTa e EXTb (P<0,05), bem como tendência à produção de excretas com maior concentração de ácido acético e ácidos graxos de cadeia curta totais (P<0,1). Por sua vez, o girassol apresentou maior digestibilidade da matéria seca (81,3%), matéria orgânica (87,4%), extrato etéreo (97,5%), energia bruta (87,3%) e tendência de maior digestibilidade da proteína bruta (84,0%) quando comparada à médias das rações processadas (matéria seca – 67,9%, matéria orgânica – 76,7%, extrato etéreo – 89,9%, energia bruta – 74,6%, proteína bruta – 77,6%) (P<0,05). A transição de uma dieta com elevada gordura (girassol) para ração balanceada promoveu melhor perfil bioquímico sérico, com redução de glicose (242,7 para 216,0 mg/dl), triglicérides (163,9 para 111,1 mg/dl), colesterol (263,6 para 184,1 mg/dl) e AST (190,8 para 113,5 U/L) (P<0,05). O melhor aporte nutricional das rações experimentais proporcionou melhora nos parâmetros hematológicos e imunocompetência dos papagaios, com maiores concentrações de hemácias, hemoglobina, hemoglobina corpuscular média, leucócitos totais, linfócitos e monócitos, quando comparado aos valores mediante ingestão do girassol (p<0,05). Ao exame radiográfico os papagaios apresentaram redução na largura da ampulheta (coração – fígado) e na relação coração fígado (p < 0,05) após o consumo da ração processada. Foi verificado que o cozimento do amido não modificou o metabolismo dos papagaios, mas a transição de dieta com elevado teor de gordura (54,4%), como o girassol, para as rações balanceadas melhorou o metabolismo reduzindo as concentrações séricas de glicose, triglicérides, colesterol e enzima hepática, além de promover aumento de hemácias e linfócitos. / Studies on food processing and its influence on metabolism are scarce for psittacines. The present study evaluated the consumption, digestibility, serum biochemistry, and radiographic parameters of blue-fronted amazon parrots after the transition from high-fat diet, based on sunflower seed, to a balanced formulation for parrot maintenance. This formulation was processed to obtain three different degrees of starch gelatinization: Pelletized food (PEL) - ingredients ground with a 2mm sieve and pelletized, with 27% of starch cooking; Low cooking extruded feed (EXTL) - ingredients ground with 2 mm sieve and extruded with low energy transference, with 82% of starch cooking; High cooking extruded food (EXTH) - ingredients ground with 0.5 mm sieve and extruded with high energy transference, with 98% of starch cooking. Thirty adults blue-fronted amazon parrots were maintained on the sunflower seed based diet for 90 days, for homogenization of the group and determination of baseline values. Later, they were distributed in a completely randomized design with 10 repetition (parrots) per treatment (experimental food) and fed with the diets for a period of 160 days. Food consumption and palatability, apparent digestibility coefficient of nutrients, concentrations of volatile fatty acids (VFAs - acetic, butyric, propionic, valeric, isovaleric and isobutyric), lactate and ammonia of the excreta and, at the beginning and at the end of the experiment hematological, radiographic and plasma concentrations of aspartate aminotransferase (AST), albumin, cholesterol, triglycerides, glucose and uric acid were determined. The data were submitted to analysis of variance and the means compared by the Tukey's test (P <0.05). The PEL food presented higher fat and starch digestibility than the EXTL and EXTH (P<0.05) and a tendency for higher excreta concentrations of acetic acid and total short chain fatty acids (P<0.1). On the other hand, sunflower seed presented higher digestibility of dry matter (81.3%), organic matter (87.4%), fat (97.5%), crude energy (87.3%), and crude protein (84.0%) than the mean of the formulated foods (P<0.05; dry matter - 67.9%, organic matter - 76.7%, fat - 89.9%, crude energy - 74.6%, crude protein - 77.6%). The transition from a high fat diet (sunflower seed) to a balanced food improved the serum biochemical profile, reducing the concentrations of glucose (from 242.7 to 216.9 mg/dl), triglycerides (from 163.9 to 111.1 mg/dl), cholesterol (from 263.6 to 184.1 mg/dl) and AST (from 190.8 to 113.6 U/L)(P<0.05). The better nutrient profile of the formulated foods improved blood parameters and immunocompetence, with higher concentrations of hemoglobin, mean corpuscular hemoglobin, total leukocytes, lymphocytes and monocytes than when the parrots were fed with sunflower seeds (P<0.05). The radiographic exam showed a reduction in the width of the hourglass (heart - liver) and heart - liver ratio after the intake of the formulated foods (P<0.05). Food processing did not modify the metabolism of parrots, but the transition from a high-fat diet (54.4%), such as sunflower seeds, to balanced diets improved parrot metabolism reducing serum glucose, triglycerides, cholesterol and liver enzyme concentrations, improving the production of red cells and lymphocytes.

O segmento farmacêutico demonstra um crescente interesse no processo de peletização, o qual consiste na aglomeração por via úmida de pós finos compostos de ativos e excipientes em pequenas unidades esféricas, com excelentes vantagens tecnológicas e terapêuticas. O objetivo do presente trabalho envolve o estudo de processos de incorporação de suspensões em péletes inertes, compostas de ativos e excipientes, utilizando dois tipos de processos: 1. Drageadeira Modificada e 2. Leito Fluidizado nas configurações top spray e bottom spray. Os ativos utilizados foram besilato de anlodipino nas concentrações de 2.5% e 5% em massa, e cloridrato de benazepril em 15% em massa, presentes nas formulações das suspensões e aplicadas em quantidades iguais nos dois processos, em um total de 9 lotes. Os indicadores de desempenho de processo utilizados para incorporação do ativo nos péletes inertes foram tempo de aplicação da suspensão (min) e taxa de aplicação da suspensão (g/min). Os péletes finais obtidos foram avaliados por meio das análises das propriedades físico-químicas: teor de umidade (%), teor de princípio ativo (%), uniformidade de conteúdo (%) e dissolução (%). Dentre os lotes testados, os processos em drageadeira e leito pelo sistema bottom spray apresentaram o menor tempo de aplicação (120 min) para a suspensão com o ativo anlodipino na concentração de 2.5%, enquanto que pelo sistema top spray apresentou um tempo de aplicação de 300 min, uma vez que este sistema foi projetado originalmente para processo de granulação. O processo em drageadeira apresentou a maior taxa real de aplicação, igual a 6.24 g/min, seguida pelo sistema bottom spray com 4.91 g/min, e o sistema top spray com 1.62 g/min, para suspensão com o ativo benazepril na concentração de 15%. Para os processos em drageadeira e leito pelo sistema bottom spray, todas as propriedades físico-químicas dos péletes deste estudo se apresentaram dentro dos padrões recomendados pela indústria farmacêutica, o que não aconteceu para o sistema top spray com relação à propriedade teor de princípio ativo (benazepril), cujo valor apresentado ficou em 12.90%, abaixo do limite inferior de 13.50%; o que não garantirá a eficácia do fármaco de acordo com a ação esperada. Os resultados apresentados ratificam os processos de peletização em drageadeira e leito pelo sistema bottom spray como os ideais pela técnica de incorporação de princípio ativo em péletes inertes. / The pharmaceutical industry has shown a growing interest in pelletization process, which consists of wet agglomeration of fine powders composed of active ingredients and excipients into small spherical unities, with excellent technological and therapeutic advantages. The objective of this work involves the study of processes of incorporation of suspensions in inert pellets, composed of active ingredients and excipients, using two types of processes: 1. Modified Coating Pan and 2. Fluid Bed in top spray and bottom spray systems. The active ingredients used were amlodipine besylate in concentrations of 2.5% and 5% by mass, and benazepril hydrochloride 15% by mass, included in the formulations of suspensions and applied in equal amounts in both processes, in a total of 9 batches. The process performance indicators used for incorporation of the active ingredient in inert pellets were time of application of the suspension (min) and rate of application of the suspension (g/min). The final pellets were evaluated by means of analyses of the physicochemical properties: water content (%), assay of active ingredient (%), uniformity content (%) and dissolution (%). Among the batches tested, the processes in coating pan and fluid bed by bottom spray system had the shortest application time (120 min) for the suspension with amlodipine besylate active with concentration of 2.5%, while the top spray system had an application time of 300 min, since this system was originally designed for granulation process. The process in coating pan showed the highest real rate of application, equal to 6.24 g/min, followed by the bottom spray system with 4.91 g/min, and the top spray system with 1.62 g/min to the suspension with benazepril hydrochloride with concentration of 15%. For the processes in coating pan and fluid bed by the bottom spray system, all physicochemical properties of the pellets of this study are presented within the standards recommended by the pharmaceutical industry, which has not happened for the top spray system with respect to property "assay of active ingredient (benazepril), whose value present was in 12.90%, below the lower limit of 13.50%, which does not guarantee the efficacy of the drug according to the expected action. The results presented confirm the processes of pelletization in coating pan and fluid bed by the bottom spray system as the ideal technique for incorporation of the active ingredient in inert pellets.

The Grate-Kiln-Cooler process is a commonly used method of sintering during iron ore pelletization, where the pellets are formed, dried, and hardened. The pellets are oxidized in the rotating Kiln, turning magnetite (Fe3O4) to hematite (Fe2O3), making the pellets attain suitable metallurgical attributes for further processing. The process is constantly exposed to thermal and mechanical stress, causing equipment degradation and thus unwanted production stops due to internal process disturbances. A suitable maintenance policy is required to cope with the risk of equipment degradation causing these production stops. Predictive maintenance (PdM) is the most current maintenance policy, utilizing a substantial amount of production data to foresee breakdowns and thus indicating the need for maintenance efforts to prevent them from occurring.           The global supplier of iron ore products, Loussavaara-Kiirunavaara Aktiebolag (LKAB), operates three pelletization plants in Kiruna. One of these pelletization plants experiences availability below desired levels. This hampers the plant from fulfilling its yearly production goals, resulting in lost revenue. This master's thesis aimed to increase the understanding of which causes influence the Grate-Kiln-Cooler process' availability. When these causes were identified, the aim was to develop a method of monitoring these to predict the need for maintenance (i.e., incorporating a PdM policy) to mitigate the risk of production stops. The work has been conducted by utilizing the systematic problem-solving DMAIC methodology.    The refractory material was identified as the primary contributor to the low availability in the investigated plant. Using principal component analysis (PCA) and statistical process control (SPC), a Hotelling T2 chart based on principal components was established to monitor the refractory material's condition. In this context, the combined usage of PCA and SPC highlighted three possible tendencies in the Kiln that potentially damaged the refractory material, causing production stops. The observed tendencies with the possibility of damaging the refractory material were; abnormally high refractory material temperatures, periods where the pellets' temperature exceeded the refractory material's temperature, and sporadic heat fluctuations in the refractory material.  The utilized Hotelling T2 chart provided a current state evaluation of the refractory material's condition and thus indicated the need for maintenance efforts. However, it was impossible to predict breakdowns by identifying patterns in either the T2-statistics or the individual charts. The inability to predict stops was derived from obstacles related to lacking documentation, deficient data, and that the time for breakdown is difficult to determine accurately. These obstacles hinder the prediction of breakdowns and, therefore, need to be dealt with to facilitate the implementation of a successful PdM strategy.

As cinzas de carvão são subprodutos da combustão de carvão mineral gerados em grandes quantidades a partir de usinas termelétricas no mundo todo. Nos últimos anos, pesquisas sobre a utilização das cinzas estão sendo desenvolvidas visando soluções sustentáveis, garantindo, assim, a preservação do meio ambiente e a saúde humana. As cinzas de carvão podem ser aproveitadas como matéria-prima para síntese de zeólita, material este que possui uma vasta gama de aplicações industriais. Em muitas dessas aplicações é requerido o uso de formas peletizadas de zeólitas. Nesse contexto, o objetivo do presente estudo foi desenvolver um método de obtenção de zeólita de cinzas leves de carvão na forma granular e avaliar seu uso como material adsorvente. A primeira etapa deste estudo consistiu na síntese e caracterização de zeólita convencional (ZCL) e de zeólita do tipo NaA com alto grau de pureza (ZA). As cinzas leves de carvão utilizadas na síntese das zeólitas foram coletadas na Usina Termelétrica Jorge Lacerda, localizada no Estado de Santa Catarina, Brasil, o maior complexo termelétrico a carvão da América Latina. O material de partida e as zeólitas sintetizadas em pó foram caracterizados em termos da composição química, composição mineralógica, morfologia, capacidade de troca catiônica, estabilidade térmica, área superficial específica, distribuição de poros e dos grupos funcionais. As fases zeolíticas formadas por tratamento hidrotérmico foram hidroxisodalita e traços de NaX. A zeólita do tipo NaA foi sintetizada por método de duas etapas apresentando grau de pureza de 84%. O valor de capacidade de troca catiônica da zeólita A com alto grau de pureza foi aproximadamente duas vezes maior do que o valor encontrado para a zeólita convencional (1,84 meq g-1 para ZCL e 3,81 meq g-1 para ZA). Na segunda etapa, os produtos zeolíticos sintetizados neste estudo foram peletizados com a aplicação de diferentes métodos. Os grânulos de zeólitas foram formados manualmente na forma de esferas na faixa de tamanho entre 3 mm e 7 mm a partir da mistura das zeólitas em pó com um ou mais agentes aglutinantes e adição de água deionizada. As diferentes metodologias experimentais de peletização das zeólitas sintetizadas foram comparadas e avaliadas por meio da determinação da capacidade de troca catiônica dos produtos obtidos, trabalhabilidade, resistência mecânica e estabilidade em água. O método de peletização no qual as argilas caulinita e bentonita foram usadas como agentes aglutinantes, na proporção de 5% em massa cada, foi considerado o melhor para a zeólita convencional. Para a zeólita A, foi selecionado o método com 10% de bentonita. Os valores de capacidade de troca catiônica dos produtos zeolíticos foram mantidos após o processo de peletização. Posteriormente foi realizado um estudo direcionado à aplicação da zeólita granular no tratamento de água. A amostra de zeólita A com alto grau de pureza peletizada, obtida pelo método otimizado, foi selecionada para ser usada como material adsorvente no processo de adsorção de íons cádmio em solução aquosa em coluna de leito fixo. Os resultados evidenciaram a potencialidade do uso da zeólita A peletizada no tratamento de efluentes. / Coal ashes are by-products of coal combustion generated in large quantities from thermoelectric plants worldwide. In recent years, research on the use of ash has been developed aiming at sustainable solutions, thus guaranteeing the preservation of the environment and human health. Coal ashes can be used as raw material for zeolite synthesis, which has a wide range of industrial applications. In many such applications the use of zeolite pelletized forms is required. In this context, the objective of the present study was to develop a method to obtain zeolite of light ash from coal in the granular form and to evaluate its use as an adsorbent material. The first step of this study was the synthesis and characterization of zeolite conventional (ZFA) and of the zeolite NaA type with a high degree of purity (ZA). The coal fly ashes used in the synthesis of the zeolites were collected in the Thermoelectric Complex Jorge Lacerda, located in the Santa Catarina State, Brazil, the largest coal burning thermoelectric complex of Latin America. The starting material and the zeolites synthesized in powder were characterized in terms of chemical composition, mineralogical composition, morphology, cation exchange capacity, thermal stability, specific surface area, pore distribution and functional groups. The zeolitic phases formed by conventional hydrothermal treatment were hydroxysodalite and traces of NaX. The zeolite of the NaA type was synthesized by a two-step method with a fusion step having a degree of purity of 84%. The value of cation exchange capacity of zeolite A with high purity was approximately two times higher than the value found for the zeolite conventional (1.84 meq g-1 for ZFA and 3.81 meq g-1 for ZA). In the second step, the zeolitic products synthesized in this study were pelletized with the application of different methods. The zeolite granules were formed manually in the form of spheres in the size range between 3 mm and 7 mm from the powder mixture of zeolite with one or more binders and addition of deionized water. The different experimental methodologies of pelletization the synthesized zeolites were compared and evaluated through of the determination of the cation exchange capacity, workability, mechanical strength and water stability. The pelletization method in which clays kaolinite and bentonite were used as binders in the proportion of 5% by weight each was considered the best for the conventional zeolite. For zeolite-A, was selected the method with 10% bentonite. The cation exchange capacity values of the zeolitic products were maintained after the pelletization process. Subsequently, a study was carried out on the application of granular zeolite in water treatment. The zeolite-A sample with high degree of pelletized purity, obtained by the optimized method, was selected to be used as adsorbent material in the adsorption process of cadmium ions in aqueous solution in a fixed bed column. The results evidenced the potential of the use of pelletized zeolite-A in the treatment of effluents.

Im Rahmen dieser Arbeit sollten Einsatzmöglichkeiten und -grenzen von kompostierten und durch Agglomeration oder Pelletierung weiter aufbereiteten Bioabfall-Gärresten untersucht werden. Außerdem sollte geprüft werden, ob durch verschiedene Zuschlagstoffe die Eigenschaften der Produkte so verbessert werden können, dass ein marktfähiges Düngeprodukt entsteht. Dazu wurden ein Feldversuch, Gefäß-, Rhizoboxen- und Bodenatmungsversuche, phytotoxikologische Tests und Regenwurm-Vermeidungstests durchgeführt. Die Ergebnisse können wie folgt zusammengefasst werden: Die Stickstoffverfügbarkeit von kompostierten Gärprodukten aus Bioabfällen ist gering, der Gehalt an Phosphor und Kalium aber hoch. Langfristig sind so der Aufbau eines Nährstoffdepots im Boden und die Einsparung anderer Dünger möglich. Die Produkte enthalten zudem basisch wirksame Bestandteile, welche die Kalkung teilweise ersetzen können. Komposte und Gärprodukte aus Bioabfällen können zur Steigerung der Humusgehalte im Boden beitragen. Ca. 80 % des enthaltenen Kohlenstoffs liegt in stabilisierter Form vor und kann im Boden sequestriert werden. Problematisch sind hohe Schwermetall- und Störstoffgehalte. Die gesetzlich vorgegebenen Grenzwerte wurden in 50 % der getesteten Chargen überschritten. Phytotoxische Effekte wurden nur in Einzelfällen festgestellt und waren nicht dosisabhängig, sondern traten punktuell auf. Die Aktivität der Mikroorganismen im Boden wurde durch Anwendung der Gärprodukte gefördert. Der Einfluss der Gärprodukte auf Regenwürmer konnte nicht eindeutig bestimmt werden. Eine Einschränkung der Habitatfunktion nach Gärproduktanwendung wurde nicht festgestellt. Die Aufbereitung durch Agglomeration oder Pelletierung ist möglich, ohne dass die wesentlichen positiven Eigenschaften davon beeinträchtigt werden. Durch Beimengung von Zuschlagstoffen können die Düngewirkung und die physikalischen Eigenschaften der Produkte verändert werden. Dies reduziert jedoch auch den Gehalt an stabiler organischer Substanz. / The scope of the present work was to determine the possibilities and limits for the application of composted digestates from biowaste on agricultural land. Furthermore it was tested whether it is possible to enhance the properties of the products by adding different amendments and to thereby create a marketable fertilizer product. A field trial, pot and rhizobox experiments, phytotoxicity tests and avoidance tests with earthworms were carried out. The results can be summarized as follows: The nitrogen availability of composted biowaste digestates is limited but they have high contents of phosphorus and potassium. Repeated application of biowaste digestate can help to establish a stable nutrient pool in the soil save up on other fertilizers. In addition, the products are characterized by basic constituents who can partly replace liming. Composts and fermentation products made from organic waste can contribute significantly to the increase of humus content in the soil. Approx. 80 % of the contained carbon is in stabilized form and can be sequestered in the soil. High concentrations of heavy metals and other contaminants are problematic. The legal limits were exceeded in 50 % of the tested batches. Phytotoxic effects were observed only in isolated cases and were not dose-dependent. The activity of the microorganisms in the soil was significantly promoted by the application of the digestates. The influence of the digestate products on earthworms could not be determined unequivocally. A restriction of the habitat function after digestate application was not detected. Processing by agglomeration or pelletizing to increase transportability and storage stability is possible without impairing the essential positive properties of the digestates. The addition of amendments can be used to adjust the fertilizing and physical properties of the products. This, however, reduces the content of stable organic matter.

Bentonite is the most preferred silicate-based binder in iron ore pelletizing. However, it is considered as an impurity due to its high SiO2 and Al2O3 content. The iron-making economy is adversely affected by the addition of bentonite or other silicate-based binders. In recent years, impurity-free alternative binders have been tested in order to replace bentonite or to lower the bentonite dosage. Organic binders yield good quality green and dry pellets. However, they fail to impart enough mechanical strength to the preheated and fired pellets as a result of insufficient slag bonding. Thus, they have not found widespread application in the industry. The addition of boron compounds into pellet mix is proposed as a potential solution to overcome the insufficient compressive strengths of preheated and fired pellets produced with organic binders. During the experiments, some organic binders and boron compounds were tested as alternative binders to bentonite either alone or in combination, for both magnetite and hematite pellets. The performances of the tested binders on pellet qualities: balling, wet pellet moisture content, drop number, pellet compressive strengths (wet - dry - preheated - fired), dustiness, porosity, mineralogy, morphology, chemical contents, reducibility and swelling index have been compared with the performances of reference bentonite binder. The results of the tests showed that, the quality of pellets are insufficient when organic binders or calcined colemanite used as binder alone. The former failed to provide sufficient preheated and fired pellet strengths, the latter failed in terms of wet and dry pellet quality. However, good quality wet, dry, preheated and fired pellets could be produced with combination of these two binders. Calcined colemanite addition into pellets made with organic binders was tested in different dosages (0.25-1.00%). Results showed that with increasing dosage of calcined colemanite both strengths of preheated and fired pellets increased linearly. It was found that as low as 0.50% calcined colemanite addition equally-performed on magnetite fired magnetite pellets at 1300oC when compared with the performance of the reference bentonite binder. However, its performance was better on hematite pellets in order to improve the pellet compressive strengths. In addition, stronger pellets could be produced at lower firing temperatures like 1100oC with the addition of calcined colemanite. The reason of the improved preheated and fired compressive strengths of pellets bonded with calcined colemanite was due to the physical melting of calcined colemanite at the contact point of iron oxide grains during thermal treatment. It was found that bentonite bonded pellets fired at 1300oC were more reducible than those of produced with calcined colemanite addition. Swelling indices of these pellets were determined in the industrially acceptable limits. The chemical and mineralogical analyses results showed that the combined binders did not contaminate the pellet composition since the organic binders burnt-out without residue and colemanite does not contain much impurity.

Zincor, a refinery in South Africa, uses the conventional roast-leachelectrowinning process to produce zinc metal. The roasting process of ZnS concentrate makes use of four Lurgi fluidized bed roasters to produce calcine (contains ZnO and ZnFe2O4 as zinc products) and SO2 gas. The roasting plant consists of two 18 m2 and two 35 m2 cross sectional area roasters. Prior to 1996, Zincor utilized air as the only oxidant and fluidizing medium in its roasters. The maximum dry feed rates that the roasters could process were 6.5 t/d.m2. In an attempt to increase production, oxygen enrichment was first trialled and then introduced into the fluidizing air. The ability of oxygen enrichment to increase the rate of the ZnS oxidation reaction allowed higher feed rates to the roasters. This was successful and oxygen enrichment was permanently implemented. That enabled dry feed rates to be maintained at 7.0 t/d.m2 and 7.3 t/d.m2 for the small and big roasters respectively. Oxygen enrichment up to 26% in the fluidizing air is utilized. Due to the highly competitive nature of the zinc industry, innovative processing techniques are necessary to be competitive. The aim of this study is to determine whether oxygen enriched air can be reduced by introducing micro-pelletized concentrate into the roaster feed blend, whilst maintaining current roaster feed rates and calcine quality. This study was executed in four parts. Firstly, the role entrainment played in influencing average particle residence time. Secondly, a study of production methods for stable micro-pellets. Thirdly, a study of the influence of oxygen enrichment and particle size on the roasting of micropellets. The fourth part of the study was introduction of micro-pellets into the Zincor roasters to determine whether oxygen enrichment could be reduced. The particle size distribution of a blend of feed concentrate to the roasters is 50% passing approximately 48 μm. This leads to entrainment values between 87% and 91%. The micro-pelletization process reduces the –500 μm fraction from 87% to 10%, which degrades to 30% during roasting. This requires that approximately 48% of the concentrate needs to be micro-pelletized to restore the 70% designed entrainment target. It was determined that entrained particles spend on average 0.46 hr to 2.44 hr in the bed compared to particles in the overflow that have residence times between 3.93 and 4.00 hr. The calculated times for entrainable particles are somewhat higher and for the bed overflow lower compared to the values measured by Spira, 1970. The required reaction time for micropellets was found to be far below their residence time inside a Zincor roaster. With a load of 20% micro-pellets introduced into the feed concentrate, the oxygen enrichment could be reduced by 60%. The quality of the calcine produced was maintained above the target of 98.8% ZnS to ZnO conversion. The results of this study have shown that the use of micro-pelletization of concentrate at Zincor reduces entrainment of particles successfully. Manipulation of entrainment through micro-pelletization can be used successfully to reduce oxygen enrichment, whilst improving production and maintaining quality at Zincor. Copyright / Dissertation (MEng)--University of Pretoria, 2009. / Materials Science and Metallurgical Engineering / unrestricted