Thesis (MScEng) --University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis deals with the development of a new process for the production of Direct Reduced Iron (DRI), intended for use specifically by small scale Electric Arc Furnace (EAF) based steel mills, who require small volumes of DRI. The term development as used here is taken to include such aspects as conceptual design, theoretical verification and initial practical testing. The rise of EAF steelmaking brought about the metamorphosis of steel scrap from a waste product into a valuable raw material. Scrap prices rose steeply during the period 1995 to 2009 compelling EAF steelmakers, wishing to have more control over the cost of their input material, to seek for scrap supplements or alternatives. DRI has become an accepted and sought after supplement, or even complete alternative, to steel scrap. Adding DRI to an EAF charge has a range of advantages, including the dilution of tramp elements and possible cost benefits, but it does have negative effects. These include the lowering of the scrap to liquid metal yield and an increase in power consumed. The effect of charging DRI to a small EAF is quantified. The maximum DRI that may be added to the burden whilst still maintaining the present steelmaking volume, is shown to be as high as 50% if charged continuously, and the maximum price payable for DRI, is shown to be approximately 80% of base grade scrap price. Finally other requirements unique to small scale EAF operators are considered in order to prepare a schedule of requirements for a DRI plant specifically for small scale EAF steel mills. A review of published information on existing DRI production technology, processes and plants is undertaken is establish the fit of existing processes to the requirements set. Initially the thermodynamics and kinetics of iron ore reduction and coal gasification, specifically downdraft gasification are reviewed. Thereafter existing processes are reviewed. Shaft based processes and rotary kiln based processes are identified as possible suitors to the requirements. Limitations of these processes, specifically heat transfer in rotary kilns and the pressure drop over a reduction shafts are investigated. Finally a typical process in each of the main process classes is adjudicated against the set requirements. None is found to match the set requirements. A new process is proposed that is claimed to better suit to small scale operation. The uniqueness of the process is embodied in the combination of existing technologies of downdraft gasification and iron ore reduction in a shaft, in a single reactor. The process consists of two shafts, one placed above the other. Iron ore is charged into the top shaft, called the pre-heat shaft, where it is pre-heated and lightly reduced to wustite with gas from the bottom shaft, called the reduction shaft. The pre-heated ore is then charged together with coal into the reduction shaft. Gasification air is drawn into the top of the reduction shaft where the coal is gasified in a downdraft gasifier, generating reduction gas which reduces the ore as the gas moves concurrently with the iron ore. The exit gas is cleaned and pumped to the pre-heat shaft where it combusted with air to pre-heat the iron ore in the pre-heat shaft. The concept is analysed thermodynamically using amongst others, FactSage, and is shown to be thermodynamically viable. To test the concept process concept practically, an extremely small pilot plant with a production rate of 2kg DRI/h, consisting of only a gasifier/reduction shaft, was designed and constructed using reduction rate data obtained from literature supplemented with data obtained from thermogravimetric analysis of CO reduction of lump Sishen hematite. Pilot Plant trials were performed using various reductant sources. The degree of metallizaion was analysed using visual inspection of cut and polished samples compared to calibrated standards. Analysis of the results indicate that coal rate and production rate influence the degree of reduction positively and negatively. The conclusions arrived at include the fact that the process is thermodynamically viable, that it was possible to reduce iron ore in a simplified pilot plant, and that the process was found to be stable and controllable. It is recommended that a larger scale pilot plant, embodying the full proposed flow sheet be erected to test the process more completely. / AFRIKAANSE OPSOMMING: Die tesis handel oor die the ontwikkeling van ‘n nuwe proses vir die vervaardiging van sponsyster. Die proses is beoog spesifiek vir gebruik deur kleinskaalse Elektriese Boogoond (EBO) gebaseerde staal aanlegte, wat kleiner hoeveelhede sponsyster benodig. Die term ontwikkeling soos hier gebruik word aanvaar om aspekte soos konseptuele ontwerp, teoretiese verifikasie en aanvanklike toetsing te behels. Die vinnige groei van EBO staalvervaardiging het skroot getransformeer van weggooiproduk tot waardevolle grondstof. Die prys van skroot het skerp gestyg gedurende die periode 1995 to 2009. EBO gebaseerde staal produsente, in ‘n poging om meer beheer te hê oor die koste van hul insetmateriaal, het hul in ‘n toenemende mate tot skrootalternatiewe gewend. Sponsyster het ‘n aanvaarde en gewaardeerde byvoeging, en selfs alternatief tot staalskroot geword. Die byvoeging van sponsyster by die lading van ‘n tipiese EBO het besliste voordele, maar het dit ook nadelige effekte. Die voordele sluit die verdunning van reselemente en moontlike kostevoordele in, terwyl van die nadele die verlaging van die skroot tot vloeistaal opbrengs, en ‘n verhoging in kragverbruik, is. Die effek van die byvoeging van sponsyster tot ‘n EBO lading word gekwantifiseer. Daar word getoon dat die maksimum hoeveelheid sponsyster wat by ‘n EBO lading gevoeg kan word terwyl die hoeveelheid staal geproduseer konstant gehou word, ongeveer 50% is indien die sponsyster kontinue gelaai word, en die maksimum prys wat vir die sponsyster betaal kan word, word bereken op ongeveer 80% van die prys van basisgraad skroot. Ander vereistes uniek aan kleinskaal EBO bedrywers word oorweeg ten einde ‘n lys van vereistes vir ‘n sponsysteraanleg, uniek aan kleinskaal EBO bedrywers, te kan bepaal. ‘n Oorsig van gepubliseerde inligting oor sponsysterproduksietegnologie word onderneem ten einde die passing van bestaande prosesse met die gestelde vereistes te kan bepaal. Nadat die termodinamika en kinetika van ysterertsreduksie en steenkoolvergassing be-oordeel is, word bestaande sponsysterprosesse beskou. Skag- en Roterende oond gebaseerde prosesse word as moontlik gepaste prosesse identifiseer. Hitte-oordrag en die drukval oor gepakte beddens, synde tipiese beperkings eie aan die twee prosesse, woord beskou. Tipiese prosesse in elk van die hoofklasse van prosesse word ten laaste be-oordeel aan die gestelde kriteria. Daar word bevind dat geeneen van die bestaande prosesse aan die vereistes voldoen nie. ‘n Nuwe proses, wat skynbaar die behoefte van kleinskaalse EBO gebaseerde staalprodusente beter bevredig, word voorgestel. Bestaande tegnolgie word in ‘n unieke opstelling geïntegreer. Reduksie word in ‘n reduksiekag gedoen as gevolg van die ooglopende massa- en hitte-oordragvoordele van ‘n skag. Reduksiegas word verkry van steenkoolvergassing in ‘n afstroomvergasser ten einde teerverwydering in ‘n naverwerkingsstap oorbodig te maak. Die uniekheid van die proses is beliggaam in die kombinasie van ‘n steenkoolvergasser en reduksieskag in ‘n enkele reaktor. Die proses bestaan uit twee skagte, een bo die ander. Ystererts word in die boonste skag, wat die voorverhitskag genoem word, gelaai. Hier word die erts voorverhit en moontlik lig gereduseer tot wustiet met gas van die onderste skag, wat die reduksieskag genoem word. Die voorverhitte erts word saam met steenkool in die reduksieskag gelaai. Vergassingslug, word in die reduksieskag gesuig waar die steenkool in ‘n afstroomvergasser vergas word. Hierdeur word reduksiegas gegenereer wat die erts verder reduseer soos dit saamstromend met die erts af beweeg. Die uitlaatgas word gesuiwer en na die voorverhitskag gepomp waar dit verbrand word om die erts te voorverhit. Die konsep is termodinamies analiseer met gebruikmaking van onder andere FactSage, en werkbaar bevind. ‘n Baie klein, vereenvoudigde proefaanleg, met ‘n produksievermoë van 2kg DRY/uur, bestaande uit slegs ‘n reduksiekag, is ontwerp en gebou met gebruikmaking van kinetika inligting uit die literatuur aangevul met inligting uit termogravimetriese analise van die CO reduksie van Sishen hematiet. Proefaanleglopies is uitgevoer met ‘n reeks reduktantbronne. Die metallisasiegraad is bepaal deur visuele inspeksie van gesnyde, gepoleerde monsters wat vergelyk is met gekalibreerde standaarde. Analise van die resultate toon dat die steenkoolkoers ‘n positiewe verband, en die produksiekoers ‘n negatiewe verband met die metallisasiegraad het. Die slotsom waartoe gekom is, is dat die proses termodinamies werkbaar is, dat reduksie van ystererts in ‘n vereenvoudigde proefaanleg bewerk kon word, en dat die prose stabiel en beheerbaar voorgekom het. Die aanbeveling word gemaak dat ‘n groter proefaanleg wat die volledige voorgestelde vloeiskema verteenwoordig, opgerig behoort te word, ten einde die proses meer volledig te kan toets.

Reatores PWR empregam, como combustível nuclear, pastilhas de UO2 acondicionadas em tubos de ligas de zircônio, chamados de encamisamento. Na sua fabricação são gerados cavacos de usinagem que não podem ser descartados, pois a reciclagem deste material é estratégica quanto aos aspectos de tecnologia nuclear, econômicos e ambientais. As ligas nucleares têm altíssimo custo e não são produzidas no Brasil, sendo importadas para a fabricação do combustível nuclear. Neste trabalho são abordados dois métodos para reciclar os cavacos de Zircaloy. No primeiro, os cavacos foram fundidos utilizando um forno elétrico a arco para obter lingotes. O segundo usa a técnica da metalurgia do pó, onde os cavacos foram submetidos à hidretação e o pó resultante foi moído e isostaticamente prensado e, a seguir, sinterizado a vácuo. A composição química, as fases presentes e a dureza no material foram determinadas. Os lingotes foram tratados termicamente e laminados, sendo que as microestruturas foram caracterizadas por microscopia óptica e eletrônica de varredura. Os resultados para ambos os métodos mostraram que a composição do Zircaloy reciclado cumpre as especificações químicas e apresentaram microestrutura adequada para uso nuclear. Os bons resultados do método de metalurgia do pó sugerem a possibilidade de produzir pequenas peças, como as tampas do encamisamento - end-caps, usando a sinterização no formato quase final (near net shape). / PWR reactors employ, as nuclear fuel, UO2 pellets with Zircaloy clad. In the fabrication of fuel element parts, machining chips from the alloys are generated. As the Zircaloy chips cannot be discarded as ordinary metallic waste, the recycling of this material is important for the Brazilian Nuclear Policy, which targets the reprocess of Zircaloy residues for economic and environmental aspects. This work presents two methods developed in order to recycle Zircaloy chips. In one of the methods, Zircaloy machining chips were refused using an electric-arc furnace to obtain small laboratory ingots. The second one uses powder metallurgy techniques, where the chips were submitted to hydriding process and the resulting material was milled, isostatically pressed and vacuum sintered. The ingots were heat-treated by vacuum annealing. The microstructures resulting from both processing methods were characterized using optical and scanning electron microscopies. Chemical composition, crystal phases and hardness were also determined. The results showed that the composition of recycled Zircaloy comply with the chemical specifications and presented adequate microstructure for nuclear use. The good results of the powder metallurgy method suggest the possibility of producing small parts, like cladding end-caps, using near net shape sintering.

Eine umweltverträgliche Methode der Rückgewinnung anorganischer industrieller Abfallprodukte bietet die thermische Behandlung im elektrischen Lichtbogenofen. Hierbei wird der Abfallstoff geschmolzen und die enthaltenen Schwermetalloxide reduziert und von der mineralischen Phase abgetrennt. Der Prozess ist sehr energieaufwändig und noch nicht vollständig verstanden. Die laserinduzierte Plasmaspektroskopie (LIBS) soll als in situ-Messtechnik dabei helfen, das Verständnis zu verbessern und die Methode zu optimieren. In theoretischen Untersuchungen wurde gezeigt, dass die Güte von LIBS-Messungen durch Normierung auch mit einer gesättigten Linie eines Matrixelementes verbessert werden kann. Für LIBS-Messungen im elektrischen Lichtbogenofen wurde ein mobiles Doppelpuls-LIBS-System für industrielle Bedingungen entwickelt, getestet und optimiert. Als Modellsystem für Schlacken wurden dotierte Glasproben verwendet. Für festes und flüssiges Glas wurden Nachweisgrenzen im ppm-Bereich erreicht, was für die Gehalte in Schlackeproben ausreicht. Ferner wurden zwei Methoden entwickelt, Flüssigkeiten mit Hilfe von festen Standards zu quantifizieren. Um die Empfindlichkeit von LIBS zu verbessern, wurde Doppelpuls-LIBS untersucht. Es konnte eine Verstärkung des Signals um das 5,1-fache erreicht werden. Es konnten Emissionen der Moleküle CaCl, MgO, YO und ZrO in LIBS-Plasmen identifiziert und simuliert werden. Eine mögliche Verwendung der Molekülemissionen stellt die Quantifizierung sehr hoher Elementgehalte dar. Trotz der schwierigen experimentellen Bedingungen erwies sich das LIBS-System als empfindlich genug. Es wurde schrittweise Mangan- und Chromoxid zur Schmelze gegeben, was in einen linearen Anstieg der LIBS-Signale resultierte. Die Reduktion und Separation von Chrom gelang und konnte mit LIBS verfolgt werden, was durch die Referenzanalysen bestätigt wurde. / The reduction process in the electric arc furnace offers a sustainable method to recover industrial inorganic waste materials. The material is molten and the containing heavy metals are reduced and separated from the mineral phase. The energy consumption of the process is very high and the detailed reactions and dynamics are not yet fully understood. Laser induced breakdown spectroscopy can provide online-measurements inside a furnace, enabling us to increase understanding and optimize the process. In a theoretical investigation it has been shown that intensity fluctuations of LIBS can be compensated by normalizing the line used for analysis with a saturated line from a matrix element. For LIBS-measurements inside the electric arc furnace, a mobile double pulse LIBS-system designed for an industrial environment was built and tested. Glass was used as a model system for slags due to its lower melting point. Limits of detection in the ppm-region were achieved for solid and liquid glass, which is sufficient sensitivity for recycling slags. Furthermore, two methods were developed to quantify a liquid using solids as standards. To improve the sensitivity of LIBS, double-pulse measurements were conducted. Signal enhancements of up to 5.1 were achieved compared to single pulse. In the LIBS plasma emissions of molucules CaCl, MgO, YO and ZrO were identified and their emissions simulated. These emissions could be used to quantify large element concentrations. Despite the difficult experimental conditions the sensitivity of the LIBS-System has been found to be sufficient for recycling-slags. When stepwise adding manganese and chromium oxide to the melt, the respective LIBS intensity increased linearly. The reduction and separation of chromium was successful, which was confirmed by reference analysis.

Esta tese apresenta os métodos de gerenciamento associados ao Pó de Aciaria Elétrica (PAE) gerado no forno elétrico a arco (FEA) e no forno-panela (FP), envolvendo dois grandes tópicos: sistema de gestão ambiental e fatores relacionados à tecnologia. O processo do PAE percorre as seguintes etapas: entrada e beneficiamento da matériaprima, preparação, carregamento e fusão de carga no FEA, formação e retirada de escória, vazamento do aço para a panela, refino no forno-panela, assim como o sistema de captação das emissões atmosféricas e destinação do PAE captado no FEA e FP. Os métodos de gerenciamento foram estruturados em cima do aprendizado técnico, qualitativo e quantitativo adquirido no desenvolvimento das atividades profissionais, dos levantamentos sobre as tecnologias disponíveis para destinação e reciclagem do PAE, dos mapeamentos das características das instalações de captação do PAE de empresas siderúrgicas, bem como das bibliografias e visitas técnicas realizadas. As informações reunidas foram empregadas para desenvolver duas matrizes de avaliação, consolidando assim, um critério para verificar as práticas de gestão ambiental e de tecnologias que estão associadas ao PAE. O principal resultado das matrizes foi a identificação e priorização das necessidades de melhorias, tanto do sistema de gestão ambiental como da área de tecnologia. A avaliação das empresas siderúrgicas, segundo estas matrizes, mostrou quais práticas possuem menores valores e que, por conseqüência, devem requerer maior esforço para melhorar seus desempenhos, bem como aquelas de maior valor que requerem uma consolidação da sua rotina para manterem o elevado nível de desempenho atingido. Como conclusão, foi obtida uma ferramenta robusta que respondeu de forma consistente a avaliação do processo do PAE e a pergunta sobre “O que se encontra mais desenvolvido, os processos de gestão ou os de tecnologia?”. As matrizes de avaliação foram preenchidas por especialistas ambientais de três Empresas siderúrgicas. O resultado obtido com essa ferramenta mostrou que os desempenhos sobre as práticas de gestão são superiores aos desempenhos das práticas de tecnologia e que esta metodologia de avaliação está apta para ser aplicada em qualquer outro processo ou empresa. Ficou evidenciado que o conhecimento e a inteligência ambiental são requisitos para assegurar que as estratégias de médio e longo prazo estejam corretamente alinhadas às boas práticas de gestão e melhores tecnologias disponíveis. / The thesis presents the methods associated with the management of the electric arc furnace (EAF) baghouse dust and ladle furnace (LF) dust. The management methods cover two broad topics: environmental management system practices and technology related factors. The EAF baghouse dust and ladle furnace (LF) dust process has the following steps: input and processing raw materials, EAF charging and melting, slag generation and removal, furnace tapping of the steel to the LF, refining in the LF, as well as the EAF dedusting system, dust recycling and final destination. The management methods were determined based on professional experience of the author, assessment of typical installations of steel plant dedusting system, bibliographies review, available technologies to EAF/LF dust destination and recycling and subject technical literature, as well technical visits undertaken. Collectively the information was used to develop two standard evaluation standard matrices which provide criteria to assess environmental management system practices and technology associated with EAF dust management. The primary goal of the assessments was to identify and prioritize areas for potential improvement - either in environmental management systems area or the technology area. The assessment results showed that steel plants which have practices with lower values, according to these matrices, should require greater effort to improve their performance, while those with good score, will require a consolidation of their routine to maintain the high level of performance already achieved. The matrices were filled by environmental experts from three steelmaking companies. Finally, as a result of this project a rigorous and reliable assessment tool was designed to evaluate the meltshop dust generation and management process and provide a quantitative answer to the following question: `Which area has achieved a higher level of development as it relates to meltshop dust management: environmental management system practices or control technology?’ The results from using this tool have shown that the performance of management practices is superior to the control technology. Furthermore, experiences captured during the assessment indicate this evaluation methodology is fully adaptable and can be applied to other processes and/or other businesses. It was clearly highlighted how knowledge and environmental intelligence are requirements to assure that the medium and long term strategies are properly aligned with the available best practices to environmental management system and control technology.

Os transformadores de potência são alguns dos elementos mais importantes dos sistemas elétricos. A confiabilidade e o bom funcionamento destes equipamentos são vitais para que as companhias de energia forneçam eletricidade com qualidade e segurança. Um dos principais parâmetros que envolvem a normalidade da operação dos transformadores é o estado da isolação interna formada pelo óleo mineral e o papel que cobre as bobinas. Danos nessa isolação resultam na degradação destes dielétricos e, por conseqüência, na diminuição da vida útil dos transformadores. Essa degradação, que advém de processos elétricos, térmicos, ou mesmo mecânicos, geram gases combustíveis cujas quantidades individuais podem indicar o tipo de falha e a gravidade do problema. Desta forma, é importante detectar os principais gases envolvidos. O objetivo deste trabalho é realizar análises e estudos quantitativos da presença de gases inflamáveis dissolvidos no óleo, surgidos através da degradação deste líquido isolante. O cerne deste trabalho está em elaborar ensaios de formação de arco no óleo e, posteriormente, aquecer o fluido para medir a quantidade dos gases combustíveis antes dissolvidos nele. Este estudo visa à melhoria na confiabilidade dos equipamentos projetados para detectar e monitorar o surgimento de gases inflamáveis no interior de transformadores de potência existentes em subestações de companhias de eletricidade. / Power transformers are some of the most important elements of electrical systems. The trustworthiness and the good functioning of this equipment permit power utilities to supply electricity with quality and security. One of the main parameters for transformer\'s operation normality is the state of the internal insulation formed by the mineral oil and the paper that covers the bobbins. Damages in this insulation cause its dielectric degradation and, consequently, the reduction of the equipment useful life. This degradation which originates from electrical, thermal, or even mechanical processes generates chemical products such as gases whose individual amounts may indicate the type of imperfection and gravity of the problem. That\'s why the detection of the main involved gases is important. This work intends to elaborate analyses and studies of the presence of inflammable gases dissolved in oil through the degradation of the insulating liquid. The principal topic of this work is the arc formation elaboration in the oil and later the heating of the oil to measure the amount of gases previously dissolved in it. This study also aims to improve the trustworthiness of the projected equipments in order to detect and monitor the sprouting of existing inflammable gases in the interior of power transformers in substations of power utilities.

O pó de forno elétrico a arco (FEA) é gerado durante a fusão de sucata ferrosa nos fornos elétricos a arco e coletado predominantemente através de filtros de mangas. Esta substância é listada como resíduo sólido perigoso de fonte específica, K061, conforme a Norma ABNT NBR 10004:2004. As maiores empresas siderúrgicas semi-integradas do mundo têm adotado para o tratamento de pó de FEA, fundamentalmente três rotas: a recuperação de zinco e chumbo, através de dois processos complementares, um piro-metalúrgico, o Wäelz kiln e outro hidro-metalúrgico, o processo de dupla lixiviação Óxido de Wäelz; a inertização através da blendagem com a cal, aditivos e água, de forma a alcançar o pH da mistura >11, o que garante que metais pesados como o chumbo, cádmio e o zinco, presentes no pó de forno elétrico, não possam se tornar solúveis, evitando consequentemente, a sua lixiviação e a disposição em aterros industriais de resíduos sólidos perigosos. Sob a perspectiva da sustentabilidade, deve ser considerada a rota da recuperação de zinco e chumbo, que para ser viável necessita reunir a geração de pó de FEA de varias plantas, o que para um país com dimensões continentais pode ser um fator de insucesso. Esse trabalho trata da reciclagem do pó de FEA através do processo de sinterização de um compósito constituído de pó de FEA aglomerado com coque, carepa e fluorita cerâmica em pelotas, aplicável a uma planta unitária. Como resultado deste processo foram obtidos dois coprodutos, o aglomerado pré-fundido, APF, com teor de óxido de ferro superior a 70%, objeto do processo de sinterização e o concentrado de zinco, com teor de óxido de zinco maior que 50%, resultante da volatilização deste metal durante o processo de sinterização e coletado através de filtro de mangas. Complementarmente foi extraído aproximadamente 90% dos óxidos de chumbo e cádmio contidos no pó de FEA inicial. A produção do APF ocorreu em escala experimental dividida em três fases, a primeira fase foi efetuada com oito formulações distintas e comprovou através de análises químicas de espectrometria por fluorescência de raios X e difratometria de raios X, a viabilidade técnica da utilização somente de resíduos sólidos industriais para fabricação do APF. A segunda fase, também com oito formulações, definidas conforme planejamento de experimentos com delineamento fatorial, teve como objetivo identificar os principais efeitos das interações entre os componentes do APF, para obtenção da mistura com formulação ótima. A terceira fase testou a intensidade das variáveis, coque e fluorita cerâmica, para a extração do zinco. As duas primeiras fases dos testes de produção em escala experimental foram realizadas em uma planta piloto de sinterização de fluxo descendente e a terceira fase em uma planta piloto de fluxo ascendente, ambas instaladas na usina ArcelorMittal Piracicaba. O APF, com a formulação ótima, foi produzido em escala industrial na planta de sinterização Metalflexi, também instalada na usina ArcelorMittal Piracicaba, e testado em alto-forno de pequeno porte. O concentrado de zinco foi caracterizado quimicamente para se avaliar o uso em segmentos industriais que utilizem este elemento. / The electric arc furnace (EAF) dust is generated during melting of steel scrap in electric arc furnaces and collected mainly through bag filters. The EAF dust is listed as hazardous waste from specific source, K061, according to ABNT 10004:2004. The major semi-integrated steel companies in the world have adopted for the treatment of EAF dust, basically three routes: the recovery of zinc and lead, through two complementary processes, a pyro-metallurgy, Waelz kiln and other hydro-metallurgical the leaching process of double oxide Waelz; the blanketing by blending with lime, water and additives in order to achieve the pH of the mixture>11, which ensures that heavy metals like lead, cadmium and zinc, present in furnace residue, can not become soluble, thereby avoiding the leaching and disposal in landfills of hazardous waste. This work suggests recycling of the EAF dust by sintering of a composite consisting of EAF dust agglomerate to coke particles (carbon source), mill scale (iron source) and ceramic fluorite (adictive agent used like fluxant) into pellets, a process known as sintering. As a result of the process is expected to obtain two by-products, the pre-cast agglomerated, PCA, with iron oxide content exceeding 70%, object of the process of sintering and zinc dust, containing more than 50% zinc oxide resulting from volatilization of this metal during the sintering process and collected by bag filter. Addition is expected to extract approximately 90% of lead and cadmium oxide contained in the initial EAF dust. The production of the PCA occurred in experimental scale divided into three stages, the first stage was performed with eight different formulations and checked by chemical analysis by X-ray fluorescence spectrometer and X-ray diffraction, the technical viability of using only solid waste industrial manufacturing PCA. The second phase, also with eight formulations, defined as planning experiments with factorial design, was tested the main effects and the double and triple interactions between the components of the PCA, to obtain the optimal formulation. The third phase was checked the intensity of the variables, coke fluorite ceramics, for removing zinc of PCA. The first two stages of the production tests were carried out on a pilot scale in a pilot plant sintering downstream and the third phase in a pilot plant xii upstream, both installed in the plant ArcelorMittal Piracicaba. The PCA, with the optimal formulation was produced on an industrial scale in the sinter plant Metalflexi also installed at the plant ArcelorMittal Piracicaba, and tested in small blast furnace. The zinc dust was characterized chemically for application in industries that use this element.

A inovação tecnológica é uma ferramenta muito poderosa utilizada para avançar estrategicamente no mundo competitivo. Esta tendência também é uma realidade nos sistemas de isolamento dos transformadores. Os isolamentos passam então a ser avaliados tanto do ponto de vista econômico, quanto do ambiental e da segurança. Em todo o mundo, são consumidos bilhões de litros de óleo isolante mineral e vegetal que, juntamente com o papel, formam a isolação interna dos equipamentos. Essa isolação ao ser degradada por uma ação térmica, química ou elétrica, não só diminui a vida útil dos equipamentos, mas também aumenta a taxa de falha e acarreta prejuízos e multas severas às concessionárias de energia. Aumenta-se a urgência em explorar o uso de óleos não fósseis, renováveis e biodegradáveis. Os fluídos isolantes vegetais, com capacidade de reduzir incêndios e riscos ambientais, já são uma realidade e alternativa possível em substituição aos óleos isolantes minerais. Como são de uso recente, os estudos sobre os gases dissolvidos nesses óleos ainda são poucos e seu uso como elementos indicadores de faltas causam desconfiança. Assim, o objetivo do trabalho foi o de criar metodologias para produzir em laboratório arcos elétricos e superaquecimento em óleos, capazes de gerar gases dissolvidos. Depois por ensaios térmicos e elétricos, realizaram-se estudos comparativos entre óleo mineral e vegetal com as técnicas disponíveis para monitoramento de faltas em transformadores. / Technological innovation is a very powerful tool used to advance strategically in the competitive world. This trend is also a reality in the insulation systems of transformers. Thus, insulation systems both from an economic, environmental and security viewpoint. Around the world are consumed billions of liters of insulating oil which jointly to paper forms the internal equipments insulation. When this insulation is damaged by thermal, chemical or electrical reaction it reduces the equipment durability, increases its failure rates, and cause great losses and severe fines to Electricity dealers. Consequently, this increases the urgency to explore the use of non-fossil oil, renewable and biodegradable. The vegetable insulating fluids is less-flammable and presents less environmental hazards, so it is a viable alternative to replace the use of mineral insulating oils. However, considering its recent use, studies involving dissolved gases in these oils are still scarce, and its use as shortages indicator, today, cause a deep distrust. Thus, the aim of this study was to create methodologies to produce, in laboratory, electric arcs and overheating in oils capable of generating dissolved gases. After a trial, was carried out a comparative analysis between mineral and vegetable oils, using the techniques available for monitoring transformers failures.

A inovação tecnológica é uma ferramenta muito poderosa utilizada para avançar estrategicamente no mundo competitivo. Esta tendência também é uma realidade nos sistemas de isolamento dos transformadores. Os isolamentos passam então a ser avaliados tanto do ponto de vista econômico, quanto do ambiental e da segurança. Em todo o mundo, são consumidos bilhões de litros de óleo isolante mineral e vegetal que, juntamente com o papel, formam a isolação interna dos equipamentos. Essa isolação ao ser degradada por uma ação térmica, química ou elétrica, não só diminui a vida útil dos equipamentos, mas também aumenta a taxa de falha e acarreta prejuízos e multas severas às concessionárias de energia. Aumenta-se a urgência em explorar o uso de óleos não fósseis, renováveis e biodegradáveis. Os fluídos isolantes vegetais, com capacidade de reduzir incêndios e riscos ambientais, já são uma realidade e alternativa possível em substituição aos óleos isolantes minerais. Como são de uso recente, os estudos sobre os gases dissolvidos nesses óleos ainda são poucos e seu uso como elementos indicadores de faltas causam desconfiança. Assim, o objetivo do trabalho foi o de criar metodologias para produzir em laboratório arcos elétricos e superaquecimento em óleos, capazes de gerar gases dissolvidos. Depois por ensaios térmicos e elétricos, realizaram-se estudos comparativos entre óleo mineral e vegetal com as técnicas disponíveis para monitoramento de faltas em transformadores. / Technological innovation is a very powerful tool used to advance strategically in the competitive world. This trend is also a reality in the insulation systems of transformers. Thus, insulation systems both from an economic, environmental and security viewpoint. Around the world are consumed billions of liters of insulating oil which jointly to paper forms the internal equipments insulation. When this insulation is damaged by thermal, chemical or electrical reaction it reduces the equipment durability, increases its failure rates, and cause great losses and severe fines to Electricity dealers. Consequently, this increases the urgency to explore the use of non-fossil oil, renewable and biodegradable. The vegetable insulating fluids is less-flammable and presents less environmental hazards, so it is a viable alternative to replace the use of mineral insulating oils. However, considering its recent use, studies involving dissolved gases in these oils are still scarce, and its use as shortages indicator, today, cause a deep distrust. Thus, the aim of this study was to create methodologies to produce, in laboratory, electric arcs and overheating in oils capable of generating dissolved gases. After a trial, was carried out a comparative analysis between mineral and vegetable oils, using the techniques available for monitoring transformers failures.

Os transformadores de potência são alguns dos elementos mais importantes dos sistemas elétricos. A confiabilidade e o bom funcionamento destes equipamentos são vitais para que as companhias de energia forneçam eletricidade com qualidade e segurança. Um dos principais parâmetros que envolvem a normalidade da operação dos transformadores é o estado da isolação interna formada pelo óleo mineral e o papel que cobre as bobinas. Danos nessa isolação resultam na degradação destes dielétricos e, por conseqüência, na diminuição da vida útil dos transformadores. Essa degradação, que advém de processos elétricos, térmicos, ou mesmo mecânicos, geram gases combustíveis cujas quantidades individuais podem indicar o tipo de falha e a gravidade do problema. Desta forma, é importante detectar os principais gases envolvidos. O objetivo deste trabalho é realizar análises e estudos quantitativos da presença de gases inflamáveis dissolvidos no óleo, surgidos através da degradação deste líquido isolante. O cerne deste trabalho está em elaborar ensaios de formação de arco no óleo e, posteriormente, aquecer o fluido para medir a quantidade dos gases combustíveis antes dissolvidos nele. Este estudo visa à melhoria na confiabilidade dos equipamentos projetados para detectar e monitorar o surgimento de gases inflamáveis no interior de transformadores de potência existentes em subestações de companhias de eletricidade. / Power transformers are some of the most important elements of electrical systems. The trustworthiness and the good functioning of this equipment permit power utilities to supply electricity with quality and security. One of the main parameters for transformer\'s operation normality is the state of the internal insulation formed by the mineral oil and the paper that covers the bobbins. Damages in this insulation cause its dielectric degradation and, consequently, the reduction of the equipment useful life. This degradation which originates from electrical, thermal, or even mechanical processes generates chemical products such as gases whose individual amounts may indicate the type of imperfection and gravity of the problem. That\'s why the detection of the main involved gases is important. This work intends to elaborate analyses and studies of the presence of inflammable gases dissolved in oil through the degradation of the insulating liquid. The principal topic of this work is the arc formation elaboration in the oil and later the heating of the oil to measure the amount of gases previously dissolved in it. This study also aims to improve the trustworthiness of the projected equipments in order to detect and monitor the sprouting of existing inflammable gases in the interior of power transformers in substations of power utilities.

Voltage fluctuations under 30 Hz in the electricity grid, leads to oscillations in the light intensity that can be perceived by human eye, which is called flicker. In this thesis, the sources of the flicker at a point of common coupling is investigated. When there are more than one flicker sources connected to a PCC, individual effects of each flicker source is determined by using a new method which depends on the reactive current components of the sources. This method is mainly based on the flickermeter design defined by the International Electrotechnical Commission (IEC), but uses the current variations in addition to the voltage variations to compute flicker. The proposed method is applied to several different types of loads supplied from a PCC and their flicker contributions on the busbar are investigated. Experiments are performed on field data obtained by the power quality analyzers (PQ+) developed by the National Power Quality Project and the method has been found to provide accurate results for flicker contributions of various loads. The PQ+ analyzers with the proposed flicker contribution detection algorithm are called Flicker Contribution Meters (FCM) and they will be installed at the points of the Turkish Electricity Transmission Network when required.