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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Scrubbing of sulfur dioxide from secondary process gases in a copper smelter / Skrubbning av svaveldioxid från sekundära processgaser vid ett kopparsmältverk

Okolo, Obiora January 2021 (has links)
Processindustrin är den största källan för utsläpp av svaveldioxid (SO2) i Sverige, vilket även inkluderar icke­järnmetallindustrin. Kopparsmältverket Boliden Rönnskär har ett miljötillstånd som tillåter SO2­-utsläpp på maximalt 3500 ton/år, en gräns som Rönnskär har legat nära under de senaste åren. För att minska svaveldioxidutsläppen på Rönnskär så har våtskrubbning (tillsammans med ett bagfilter för stoftrening) föreslagits som en metod för att rena de SO2-­bärande och intermittenta tappgaserna från flashugnen. För att göra ett optimalt val av våtskrubberteknik för ändamålet, undersöktes, utvärderas och jämfördes våtskrubbningstekniker baserade på de följande kemikalierna i denna rapport: lut, soda, peroxid, kalk and zinkoxid. Mätningar gjordes också på sekundärhuvsgaserna från konvertrarna, som också kan användas i skrubbern då flashugnens tappgaser har ett fluktuerande flöde. Vidare gjordes tester på olika processvatten på Rönnskär, som skulle kunna återanvändas i skrubbern. Skrubbrarna utvärderades sedan baserat på indata och olika systemkrav med hjälp av simulerings­ och designprogram samt teoretiska beräkningar. Resultaten visade att det är rimligt att rena sekundärhuvsgaser i skrubbern, då de innehöll ca 280 ton SO2/år. Detta kan jämföras med flashugnens tappgaser som innehöll ca 445 ton SO2/år. Bland skrubbrarna, så utvecklade peroxidskrubbern sig till att vara den mest attraktiva tekniken på grund av dess relativt låga livscykelkostnader och dess lämplighet med både lakverket och flashkyltornsprocessvattnet. De andra teknikerna med packade torn, lut­ och sodaskrubbern, hade högst livscykelkostnader, huvudsakligen på grund av deras höga kemikaliekostnader. Sodaskrubbern, som var den billigare av de två natriumbaserade skrubbarna, skulle kunna vara lämplig ändå på grund av teknikens enkelhet. De öppna tornen hade lägre livscykelkostnader jämfört med de packade tornen. Dock så hade kalkskrubbern flera nackdelar som gör att den inte är ett lämpligt alternativ. Zinkoxidskrubbning har i sin tur inte studerats tillräckligt och är en relativt oprövad teknik, men den bör studeras vidare då den skulle kunna integreras med zinksmältningsprocessen på Rönnskär. Användningen av processvatten i skrubbern skulle leda till en nettominskning av processvatten till reningsverket. Det skulle även leda till minskade reagentkostnader ifall en stripper installeras för att ta bort SO2 från processvattnen innan de går in i skrubbern. / The processing industry is the largest source of sulfur dioxide (SO2) emissions in Sweden, which includes the non­ferrous metals industry. The copper smelter Boliden Rönnskär has an environmental permit to emit a maximum of 3500 tonnes of SO2/year, a limit that the smelter has been close to in recent years. To reduce the SO2 emissions at Rönnskär, wet scrubbing (together with a bag filter for dust cleaning) has been proposed as a method for cleaning the SO2­-bearing, intermittent tapping gases from the flash furnace. To find the optimal wet scrubbing technique for the purpose, wet scrubbing techniques based on the following reagents were investigated, evaluated and compared in this report: caustic soda, soda ash, peroxide, lime and zinc oxide. Measurements were also done on the secondary hood gases from the converters, which could make use of the remaining capacity in the scrubber. Further, tests were conducted on various process waters from other processes at Rönnskär, waters that could be reused in the scrubber. The scrubber techniques were then evaluated based on the input data and system requirements using simulation and design software as well as theoretical calculations. The results suggested that it is reasonable to clean secondary hood gases in the scrubber, as they contained approximately 280 tonnes of SO2/year. This could be compared to the flash tapping gases that contained approximately 445 tonnes of SO2/year. Among the scrubbers, the peroxide scrubber evolved as the most attractive technique due to its relatively low life cycle cost and due to its suitability with the leaching plant and the flash cooling tower process water. The other packed tower techniques, caustic soda and soda ash had the highest life cycle costs, mainly due to their high reagent costs. The soda ash scrubber, which was the cheaper of the two sodium­-based scrubbers, could still be a suitable alternative due to its simplicity. The open spray towers had lower life cycle costs than the packed towers. However, the lime scrubber had several disadvantages that makes it an unsuitable alternative. In turn, the zinc oxide scrubber is a relatively under­researched and unproven technique, but should still be studied further as it could be integrated with the zinc smelting process at Rönnskär. The use of process waters in the scrubber would lead to a net reduction of process water to the process water treatment plant and would lead to reduced reagent costs if a stripper is installed to remove the SO2 from the process waters before entering the scrubber.
22

Reproductive hazards in an industrial setting : an epidemiological assessment

Wulff, Marianne January 1996 (has links)
Background: As more women of childbearing age engage in the workforceand a lot of new chemicals are available, a growing interest of diagnosing andpreventing reproductive disorders due to occupational and environmentalexposure has occurred. The source location of this thesis is the Rönnskärcopper smelter which is situated in the north of Sweden, in the municipality of Skellefteå. Emissions from the smelter, which have diminished during theperiod 1975-1990 include sulphur dioxide and heavy metals, especially lead,arsenic, cadmium, copper, mercury and zinc. Reproductive studies from the1970s in and around the smelter reported increased risks of spontaneousabortions, malformations and lower birth weight. The aim of this thesis wasto perform a broad and long-term epidemiological assessment of adversereproductive outcome in and around the smelter and to determine if theexposed population suffered from reproductive disturbances during the recentdecades. Subjects and methods: The study involve two main sources of data. Onewas a retrospective cohort formed through record linkage of populationregisters, the medical birth register (1961-90), the register of congenitalmalformations (1973-90) and the cancer register (1961-90). As another source,information on reproductive history, life-style and work related factors wasobtained from a questionnaire study in 1992. An exposed population wasdefined as smelter workers and their children, and also neighbours to thesmelter and their children. Results: In the register study, compared to the reference population, nooverall significant increased risk of malformations, childhood cancer, low birthweight or perinatal death was found in the exposed group. In thequestionnaire study, regarding infertility, no environmental effects were found.Also, no increased risk of a prolonged waiting time to pregnancy or increasedrisk of spontaneous abortions were associated with occupational or environmentalfactors. Conclusion: With the lack of a high statistical power in mind, due to smallsample sizes in some of the studies, the summary of our findings includingseveral outcomes, different epidemiological study designs and studies coveringa long period of time gives no evidence for any increased risk of reproductivehazards due to occupational or environmental exposure. / digitalisering@umu
23

Aluminum levels in the O-horizon of soils near Sundsvall, Sweden : Are levels of Al elevated due to smelter emission? / Aluminium koncentrationer i jordars O horisont nära Sundsvall, Sverige : Är Al koncentrationerna förhöjda till följd av utsläpp från smältverket?

Sundin, Mattias January 2023 (has links)
Aluminum (Al) is a potentially toxic element for humans, animals, and plants. Al emitted from smelter plants is one source of Al that may be responsible for increased exposure to humans and the environment. In this study I investigated whether the Kubikenborg aluminum smelter (Kubal AB) emitted Al to such extent that it can be detected above regional background concentrations in soils and plants. The study was conducted by analyzing O- horizon cores and Scots’ pine (Pinus sylvestris) needles along two transects using X-ray fluorescence spectrometry (XRF). In the O-horizon cores, Al concentrations along the two transects (mean conc. 5250 mg kg-1 in T1 and 3472 mg kg-1 in T2) did not decrease with distance from the smelter. In Scots’ pine needles, Al concentrations (mean conc. 491 mg kg-1 in T1 and 590 mg kg-1 in T2) decreased significantly with distance along transect T2. Aluminum showed high negative co-variance with soil organic matter content (R2 = 0.47) and positive with silicon (Si) and titanium (Ti) in the soil (R = 0.84 and R = 0.86 respectively), suggesting that mineral dust is the main source of Al. However, the Al/Si ratio of the soil decreased with increasing distance from the smelter along T1, indicating a possible additional source of Al besides that of soil dust that may originate from smelter emission. Nevertheless, I found no strong support for detectable Al emissions in humus and Scots’ pine needles near the Kubal AB smelter.
24

Contamination atmosphérique en éléments traces au sein de tourbières ombrotrophes situées à proximité d’une fonderie de cuivre

Kessler-Nadeau, Max Émile 08 1900 (has links)
La région de Rouyn-Noranda est fortement touchée par la contamination en éléments traces (ET), tels que l’arsenic (As), le cadmium (Cd), le cuivre (Cu) et le plomb (Pb), provenant des dépositions atmosphériques générées par les émissions de la fonderie Horne. Bien que des études aient démontré l’influence biogéochimique de la fonderie sur l’environnement, aucune recherche ne s’est penchée spécifiquement sur la distribution spatiale des ET dans les écosystèmes terrestres situés en périphérie de la fonderie. Ce mémoire vise donc à cartographier l’étendue spatiale des ET dans la région de Rouyn-Noranda et d’évaluer leurs distributions, spatialement au sein du territoire, mais également entre les composantes écosystémiques de tourbières exposées à des niveaux contrastants de déposition. À partir des concentrations analysées au sein du bryophyte Sphagnum fuscum, échantillonné dans 54 bogs jusqu’à 50 km à l’est de la fonderie, la modélisation de la distribution spatiale des ET a été réalisée par l’entremise d’interpolation spatiale par krigeage. La contamination en ET est plus importante près de la fonderie et diminue significativement dès que la distance augmente de cette dernière. De même, les niveaux d’ET dans la tourbe, l’eau interstitielle et les composantes (racine, tige et feuille) de quatre espèces végétales caractéristiques des tourbières, sont systématiquement plus importants dans les sites situés à 10 km de la fonderie que dans ceux à 25 km. Au sein des végétaux, la remobilisation verticale des ET est limitée et ces éléments s’accumulent en majorité dans les racines, qui sont exposées aux concentrations élevées d’ET dans la tourbe et l’eau interstitielle. Mes travaux ont démontré que l’étendue de la contamination environnementale en ET à Rouyn-Noranda est fonction de la distance à la fonderie Horne et que la mobilité des ET dans les tourbières se concentre à l’interface sol-eau-racine. / The Rouyn-Noranda region is strongly affected by trace element (TE) contamination, such as arsenic (As), cadmium (Cd), copper (Cu) and lead (Pb), from atmospheric deposition of the Horne copper smelter emissions. Although studies have demonstrated the biogeochemical influence of the Horne smelter on the environment, no research has particularly investigated the spatial distribution of TEs in the vicinity of the smelter. This thesis aims to map the spatial extent of TEs in the Rouyn-Noranda region and to evaluate their distribution between the ecosystem components of peat bogs exposed to contrasting levels of TE depositions. Based on the TE concentrations analyzed in the bryophyte Sphagnum fuscum, sampled in 54 bogs up to 50 km east from the smelter, we modelled the spatial extent of TE through spatial kriging interpolation. Trace element contamination is higher near the smelter and decreases with increasing distance from the latter. Consequently, TE levels in the peat, pore water, and components (roots, shoots, and leaves) of four plant species within bogs are consistently higher at sites 10 km from the smelter than at sites 25 km away. Within plants, the vertical translocation of TE is limited, and these elements accumulate specifically in the roots, which are exposed to considerable concentrations of TE in the peat and in the pore water. My work has shown that the extent of the environmental contamination of TEs in Rouyn-Noranda is a function of the distance from the Horne smelter and their mobility in peatlands is localized at the root-soil-water interface.
25

Removing Reds from the Old Red Scar: Maintaining and Industrial Peace in the East Tennessee Copper Basin from the Great War through the Second World War

Simson, William Ronald 19 March 2010 (has links)
This study considers industrial society and development in the East Tennessee Copper Basin from the 1890s through World War II; its main focus will be on the primary industrial concern, Tennessee Copper Company (TCC 1899), owned by the Lewisohn Group, New York. The study differs from other Appalachian scholarship in its assessment of New South industries generally overlooked. Wars and increased reliance on organic chemicals tied the basin to defense needs and agricultural advance. Locals understood the basin held expanding economic opportunities superior to those in the surrounding mountains and saw themselves as participants in the nation’s industrial and economic progress, and a vital part of its defense. The study upends earlier scholarship contending local industrial concerns acted proactively to challenges from farmers harmed by industrial pollution; investigation shows firms hesitated to initiate new production processes and manipulated local elections. Partisan developments woven amid all this underscore errors in assuming ancient regional affinity for Republicans. Confederate heritage gave Democrats an historic advantage that fractured before New Deal progressivism and expanding basin Republican power. Markets forced basin firms to merge and embrace technological change affecting working people’s relationships, forcing workers to improve skills or settle for low-skill jobs. Excepting TCC managers and supervisory staff, provincialism ruled; suspicions and competitiveness among workers grew as most miners lived a few scattered villages and most managers and craftsmen settled in the basin’s “Twin-cities” district. Early union efforts collapsed before union mismanagement, rational management and a company union based upon Sam Lewisohn’s ideals. Management managed to wrest control of its industrial relations despite the effects of Depression and the New Deal’s empowerment of workers. Workers’ infighting, reflecting neighborhood demographics and ideological differences, benefitted TCC; it convinced locals TCC could best protect industrial peace. The submissive AFL union installed fit of ownership’s nationally recognized program for industrial relations reliant on federal power. After competition crippled local industry, locals continued their reliance on government: to investigate the medical consequences of extraction work and coordinate environmental restoration. Recent regional anti-government populism makes the basin’s peculiar historic reliance on federal help engaging.
26

Modelagem Paramétrica de Cubas Eletrolíticas para Predição do Efeito Anódico. / Parametric modeling of electrolytic smelter pot for anodic effect prediction.

SILVA, Antonio José da 05 June 2009 (has links)
Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-09-06T13:31:47Z No. of bitstreams: 1 Antonio_José_da_Silva2.pdf: 2564341 bytes, checksum: ff7454362aecf3bf6afd177edfd5c821 (MD5) / Made available in DSpace on 2017-09-06T13:31:47Z (GMT). No. of bitstreams: 1 Antonio_José_da_Silva2.pdf: 2564341 bytes, checksum: ff7454362aecf3bf6afd177edfd5c821 (MD5) Previous issue date: 2009-06-05 / FAPEMA / The Anode effect that occurs in electrolytic smelter pot is responsible for gases such as PFC s. These gases contribute to the greenhouse effect, and in addition jeopardizes its productive capacity. From the voltage (output) and current (input) are estimate ARX and OE models of the electrolytic smelter pot using the Systems Identification Theory, the ARX and OE models of the electrolytic smelter pot are built to represent the steady state operation and the anode effect occurrence. After the simulation are chosen the models with better adjustment to the measure exit. For the selection are used established criteria along the research, the ARX and OE models of electrolytic smelter pot, are built to represent the full state operation of the electrolytic smelter pot. Based on real data and via algebraic properties, the models generate the functions of specific transfer of each model that are validated with real data obtained in the industry, the answer in time, in the convergence frequency and speed are analyzed. From the transfer function is made the representation of the normal stage of operation of the electrolytic smelter pot, and by the properties of the estimate model is made the prediction the anode effect identifying the increase of the voltage in the validation stage. Therefore, this work introduces the investigation of ARX and OE parametric models how better represent the operation of the electrolytic smelter pot to can enable the prediction of the anode effect in the productive process of the aluminum. In this dissertation, we propose the models development in the domain of the continuous and discreet time with a study of her transitory answers and of steady state as well as your answer in frequency of your normal operation and in the phase that precedes the anode effect. / O efeito anódico que ocorre nas cubas eletrolíticas é responsável pela emissão de gases como os PFC s, gases esses, que contribuem para o efeito estufa, além de comprometer sua capacidade produtiva. A partir dos sinais de tensão (saída) e corrente (entrada) são estimados modelos ARX e OE da cuba eletrolítica utilizando a Teoria de Identificação de Sistemas. Após a simulação são escolhidos os modelos com melhor ajuste à saída medida. Para a seleção são utilizados critérios estabelecidos ao longo da pesquisa. Os modelos ARX e OE das cubas eletrolítica, são construídos para representar o pleno estado de funcionamento da cuba. Baseados em dados reais e via propriedades algébricas, os modelos geram as funções de transferência específicas de cada modelo que são validadas com dados reais obtidos na indústria, a resposta no tempo, na freqüência e velocidade de convergência são analisadas. A partir da função de transferência é feita a representação da fase normal de funcionamento da cuba eletrolítica, e pelas propriedades do modelo é feita a predição do efeito anódico identificando o aumento da tensão na fase de validação. Portanto, este trabalho apresenta a investigação de modelos paramétricos ARX e OE que melhor representam o funcionamento da cuba eletrolítica para possibilitar a predição do efeito anódico no processo produtivo do alumínio. Nesta dissertação propomos o desenvolvimento de modelos no domínio do tempo contínuo e discreto com um estudo das suas respostas transitória e de regime permanente assim como sua resposta em freqüência de seu funcionamento normal e na fase que antecede o efeito anódico.

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