234 resultados para chalcopyrite leaching


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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The crop demand by nitrogen varies from one crop to other as well as the amount and application time, and this nutrient can be lost by leaching, volatilization and erosion. The objective of this study was to evaluate doses, sources and times of nitrogen application in rice of high lands cropped in no till system. The work was conducted in Selviria, State of Mato Grosso do Sul, Brazil, in a soil originally under Cerrado vegetation. A randomized blocks design, with the treatments disposed in a factorial scheme 5x3x2 was used. The treatments were constituted by five nitrogen doses (0, 50, 100, 150 and 200 kg ha(-1)), three nitrogen sources (urea; ammonium sulfonitrate plus nitrification inhitor and ammonium sulfate) and two application times (at sowing or at flower bud differentiation), with four repetitions. The sources of nitrogen, as well as the application times had similar effects for most of evaluations. The N doses influenced linearly or with quadratic adjustment the plant height, N leaf content and grains yield, in the two growing seasons. The chlorophyll content and the number of ears m(-2) were affected only, in the first year. The highest yield in the growing season of 2007/08 was obtained with the dose of 149 kg ha(-1) of N. In 2008/09 growing season the increase of N doses provided increment in the grains rice yield, until the maximum dose evaluated (200 kg ha(-1) of N).

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The Cu-Au mine of Chapada is located in the municipality of Alto Horizonte, in the northwestern portion of Goiás state and is inserted in the geological context of the Brasilia Belt, specifically the Mara Rosa Magmatic Arc, which hosts important deposits of Au and Cu-Au. The rocks found in the study area belong mainly to the Volcano-Sedimentary Sequence of Mara Rosa and are composed of basic to acidic metavolcanic rocks, psammiticpellitic metasedimentary rocks, chemical rocks and also hydrothermal products. Late intrusions occur and are represented by pegmatitic dikes and tonalitic bodies. The ore deposit of the Chapada mine is formed predominantly by the chalcopyrite-pyritemagnetite association, where pyrite is the most abundant mineral. Through the structural mapping of the mining fronts, it was able to recognize three deformational phases (Dn, Dn +1, Dn +2). During the Dn phase, isoclinal recumbent folds were formed, in association with amphibolites facies metamorphism. Later, in phase Dn +1, there was formation of drag folds and intrafolial folds in association with retrograde metamorphism in the greenschist facies. The deformational phase Dn +2, in its turn, was responsible for late symmetrical folding of the foliation, with NS and EW axes, resulting in an interference pattern of the dome-and-basin type

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The present work deals with the study on the evaluation of the human health risks caused by the leaching of hydrocarbon products from a gas station in Sumaré-SP. First, a geoenvironmental diagnosis had to be done, where information such as: history of the area, chemicals involved, geological characteristics, transport, chemical analysis, were used to make it. The geoenvironmental diagnosis was used in the software RBCA tier 2 which established the risks by all possible pathways. The results indicated that there are risks for groundwater ingestion for commercial (on site and off site) and residential receptors and 10 that there´s risk for inhalation of vapors in enclosed space for the commercial receptor on site. The evaluation also calculated the specific target levels that the area needs to show, in order not to harm human beings and the environment. That makes RBCA a great tool that can helps the remediation actions needed to be done so that the human being and the environment remain secure.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Main occurrence of Cu-Au in Goias Magmatic Arc, the Chapada mine fits into the geological context of the Brasilia Fold Belt, specifically in the Mara Rosa Magmatic Arc. Four targets, named Hidrotermalito Norte and Sul, NW Chapada Mine Portion and Suruca, are situated in this context, which includes ortogneisses and rocks from the Mara Rosa volcanic-sedimentary sequence. All these targets have been studied due to the possibility of presenting a great potential in Cu-Au, as well as the Chapada mine. Hidrotermalitos Norte and Sul targets presents four lithological sequences, which were identified as: quartz-muscovite schist; muscovite quartzites and kyanite quartzites; quartz-biotite-amphibole schist with pyrite and epidote-amphibole-biotite gneisses with muscovite; muscovite-biotite gneisses. They are metamorphosed to amphibolites facies and retrogressive greenschist facies. Sulfetation represented mainly by pyrite. In the NW Chapada Mine Portion, three main lithological groups were identified and classified as biotite gneisses; honblende-quartz-biotite-schist; amphibolites, with the first group metamorphosed in greenschist facies (low grade), and the other two groups metamorphosed in amphibolites facies, with subsequent retrogressive metamorphism in greenschist facies. Sulfetation is represented by chalcopyrite and pyrite. Finally, also three main lithological groups were identified in the Suruca target, classified as garnet-chlorite-epidote-eiotite gneiss; biotite gneiss and chlorite-biotite gneiss with epidote and muscovite; muscovite-quartz schist, all them metamorphised in amphibolites, with retrometamorphism in greenschist facies. Sulfetation represented by pyrite and sphalerite

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In the Serra de Jacobina, localized in the North Central portion of the state of Bahia, occours the Jacobina Group. It’s a sedimentary basin and the gold deposit is stocked on the basal portion, which consist on quartzites intercalated with oligomítico metaconglomerates of Serra do Córrego Formation. There are controversies about the origin of the gold mineralization, but the currently most accepted hypothesis corresponds to a paleoplacer deposit with subsequent ore remobilization and concentration by hydrothermal process. The sulphidation is one of the main results of hydrothermal process, which was more detail characterized, besides identifying if there was more than one sulfides phase generation and its relationship with gold mineralization. The analyzes were performed from the main reef's (metaconglomerates mineralized levels) of Mine Canavieiras: Maneira, Holandez, Liberino, Piritoso, MU and LU. Chemical analyzes semi-quantitative were developed with EDS in MEV and also petrographics analyses. The main sulfide is pyrite, followed by chalcopyrite. Six groups of pyrite were classified according with chemical composition, however they show similarities in their habit and occurrence. Were identified four types of chlorite, labeled A, B, C, D. Gold occurs in free form, associate to pyrites, to Fe-Ti-Muscovite, to chlorite type B and to microfractures with iron hydroxide. Gold presents three different compositions: pure, with Ag or associated with U-Zr. The results of chemical analysis showed that the hydrothermal process have as their main source, ultramafic rocks present in the Jacobina Basin

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Agricultura) - FCA

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Pós-graduação em Ciência dos Materiais - FEIS