Orientadores: Jacinta Enzweiler, Otávio Augusto Boni Licht / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-22T23:05:18Z (GMT). No. of bitstreams: 1 Barros_FernandaCeciliaDias_M.pdf: 7061274 bytes, checksum: fb0d51f8e86e9f4450483280c29b5fc9 (MD5) Previous issue date: 2012 / Resumo: O uso da geoquímica de gases ou emanometria é um método com grande potencial em prospecção mineral de depósitos não aflorantes e/ou encobertos por rochas não-mineralizadas, porém ainda é pouco utilizado. A temperatura de formação da mineralização é um fator determinante à presença de alguns elementos- traço, dentre eles o Hg. Existe uma predileção do Hg por depósitos de zinco de baixa temperatura do tipo epitermal e stratabound. O depósito de Zn-Pb-Cu de Santa Maria, localizado na Bacia do Camaquã, município de Caçapava do Sul (RS) contém Hg associado à mineralização e, por isso, foi escolhido como área piloto para testes de emanometria. O objetivo desta pesquisa foi medir a concentração de Hg gasoso in situ e avaliar a sua potencialidade na prospecção de depósitos sulfetados de zinco. A concentração de Hg gasoso no ar foi medida ao longo de um percurso de 11 km com um espectrômetro portátil de absorção atômica a fim de definir a concentração de Hg atmosférico local, que variou de 2 a 10 ng/m3. O Hg gasoso no solo foi medido em buracos escavados em profundidades de 30 e 50 cm e a sucção do ar para o interior do espectrômetro, atingindo valor máximo de 19 ng/m3 acima da mineralização. Amostras de solo e de duas espécies de vegetação também foram analisadas. O tratamento estatístico dos resultados mostrou que o background de Hg medido nas amostras de solo variou entre 3,9 e 28 ng/g Hg, enquanto o background obtido para as amostras de carqueja (Baccharis trimera) variou entre 10,5 e 38 ng/g Hg. Os valores de background local e o padrão de anomalia gerado demonstraram que o Hg atmosférico, o Hg gasoso (especialmente em 30 cm) e a carqueja foram os meios amostrais mais eficientes para detectar a mineralização pela medição do mercúrio. As amostras de solo e vassourinha (Dodonea viscous) geraram uma fraca resposta geoquímica da mineralização. A localização e a dimensão das anomalias de Hg puderam ser associadas à mineralização sulfetada de Santa Maria, ao sistema de Falha Três Figueiras e atividades antrópicas na área / Abstract: The use of gas geochemistry or emanometry is a method with great potential in mineral exploration of deep ore deposits covered by non-mineralized rocks, although rarely used. The temperature of the mineralization is a determinant factor for the presence of certain trace elements, including Hg. There is an affinity of Hg for low temperature zinc deposits, especially epithermal and stratabounds type deposits. The Zn-Pb-Cu deposit of Santa Maria, located in Camaquã Basin, Caçapava do Sul (RS) contains Hg associated to the mineralization and was chosen as pilot area to test emanometry. The objective of this research was to measure gaseous Hg in situ and to evaluate the potentiality of its use in prospection of zinc sulfide deposits. The air Hg gas concentration was measured along a trajectory of 11 km with a portable atomic absorption spectrometer, resulting in atmospheric Hg concentrations that varied between 2 to 10 ng/m3. The Hg gas in soil was measured in holes excavated at depths of 30 and 50 cm by air suction into the spectrometer, attaining 19 ng/m3 over de mineralization. Soils and two species of vegetation were also sampled and analyzed. The statistical treatment of data showed that background Hg in soils samples varied between 3.9 and 28 ng/g, while the Hg in gorse (Baccharis trimera) varied between 10.5 and 38 ng/g. The local background values and the pattern of the anomaly showed that atmospheric Hg, gas Hg in soil (especially at 30 cm depth) and gorse were the most efficient sample media to detect the mineralization by using Hg. The soil and florida hopbush (Dodonea viscous) produced a weak geochemical response of the mineralization. The location and the dimension of Hg anomalies could be associated to the Santa Maria deposit, to the Três Figueiras fault system and to anthropogenic activities in the area / Mestrado / Geologia e Recursos Naturais / Mestra em Geociências

Doctorat en sciences politiques / info:eu-repo/semantics/nonPublished

Ce travail traite d’un problème de pollution liée à la présence de métaux de base dans des passifs environnementaux issus d’un traitement métallurgique des minerais sulfureux cuivre – zinc provenant de la mine de Kipushi en République Démocratique du Congo. L’objectif principal de ce travail a été d’arriver à proposer des scénarios de gestion durable au passif environnemental de la filière présentant les risques environnementaux les plus élevés. Pour cela, on a d’abord procédé à une identification des différents problèmes environnementaux tout au long de la filière de traitement sur les quatre sites d’exploitation. Ensuite on a prélevé des échantillons puis procéder par des tests de disponibilité à la lixiviation à l’eau déminéralisée pour évaluer les fractions solubles des métaux de base présents et aussi par des tests de conformité de mise en décharge afin de classer ces rejets conformément à la directive européenne 2003-33-CE. Ainsi, les rejets Ex – UZK ont été identifiés comme les plus dangereux de la filière au regard de cette directive, car les quantités lixiviées de cuivre et de zinc dans ces rejets ont dépassé largement les limites fournies par la directive, et donc ils ne peuvent même pas être mis en décharge de classe I sans traitement métallurgique préalable pouvant permettre leur dépollution. <p>Par contre, les autres rejets de la filière, en l’occurrence les rejets de flottation de Kipushi et les scories de fusion pour matte de cuivre, peuvent eux être acceptés en décharge de classe I, sans traitement préalable au regard des limites fournies par la même directive. Les procédés de lixiviation acide chaude et de digestion ont été proposés et retenus comme scénarios de gestion durable à appliquer à ces rejets Ex – UZK, car ils se réalisent tous deux en milieu acide sulfurique d’une part et d’autre part leur application et surtout leur faisabilité en République Démocratique du Congo reste possible ;en outre ils aboutissent à des nouveaux rejets contenant le fer sous forme d’hématite, pouvant être stocké aisément et durablement dans la nature, ce qui est conforme au principe du développement durable. Nous avons tenté de modéliser ces deux scénarios en discutant et comparant la circulation des flux de matière dans les deux procédés, d’abord autour de chaque opération métallurgique unitaire, et ensuite sur l’ensemble du procédé. Ainsi nous avons pu chiffrer tous les flux entrant et sortant dans le système étudié, en considérant 1000 kg de rejets Ex –UZK alimentés. Cette quantification nous a permis de comparer les coûts opératoires de ces deux procédés. Les résultats obtenus dans la présente étude sont encourageants et nous ont permis de formuler des recommandations pour les études ultérieures éventuelles dont les résultats pourront l’enrichir davantage, notamment sur les aspects technologiques, économiques et environnementaux, de manière à faciliter les applications sur terrain.<p><p>This work deals with environmental liabilities consisting of base metals pollution due to metallurgical processing of copper – zinc sulphide ores in Kipushi mine in Democratic Republic of Congo. The main objective of this work was to propose sustainable management scenarios for the most important environmental liabilities from metallurgical sector. For this purpose, liabilities were first identified on four metallurgical plants. Then, leaching tests with deionized water were carried out to assess the soluble fractions of base metals. These effluents were also classified according to the test described in european decision 2003-33-EC, which determines the conformity of waste to landfill. Ex – UZK effluents are the most dangerous from this sector, according to this directive, since the quantities of leached copper and zinc were far beyond the limits :they cannot be sent to class I landfill without prior metallurgical processing. However, other effluents like flotation wast and Lubumbashi slag originating from melting for copper matte, are acceptable without prior treatment. Hot acid leaching and digestion were proposed as sustainable management scenarios for to these Ex – UZK waste because :both can be performed in sulfuric acid and they are feasible in Democratic Republic of Congo. They also lead to an iron – rich waste consisting of hematite that can be stored easily and sustainably in nature, which is consistent with the principle of sustainable development. We have modeled these two scenarios by discussing and comparing the flows in both processes, first for each individual metallurgical unit process, and then for the whole chain of value. So we could assess all the inputs and outputs of the studied system, expressed per ton of Ex – UZK waste. The operating costs of both processes were calculated and compared. The results are encouraging. Recommendations were proposed for further studies, in order to investigate more deeply the technological, economical and environmental aspects, to facilitate the final application. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished