Análise proteômica diferencial de Acidithiobacillus ferrooxidans em resposta aos sulfetos minerais calcopirita e bornita e efeito de uma proteína recombinante de A. ferrooxidans LR contendo cisteína na oxidação bacteriana da calcopirita

Pós-graduação em Biotecnologia - IQ

Efeito do potencial de óxido-redução na biolixiviação da calcopirita

Pós-graduação em Biotecnologia - IQ

Sensores ópticos para quantificação de sulfeto de hidrogênio em matrizes gasosas por espectrometria de floorescênica do UV-visível e espectroscopia de absorção no infravermelho: João Flávio da Silveira Petruci. -

Pós-graduação em Química - IQ

Platinum-Group Minerals in Chromitites of the Niquelandia Layered Intrusion (Central Goias, Brazil): Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

A variety of platinum-group-minerals (PGM) have been found to occur associated with the chromitite and dunite layers in the Niquelandia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary), and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary). Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

Caracterização mineralógica, petrológica e química da sulfetação nos reef's da mina Canavieiras, Jacobina, Bahia

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

Mapeamento geológico e petrologia dos complexos máfico-ultramáficos de Mangabal Sul e Mangabal Norte, região de Sanclerlândia, Goiás

The Mangabal Sul and Mangabal Norte mafic-ultramafic complexes are interpreted as intrusive stratiform bodies in the Goiás Magmatic Arc during the Brazilian cycle, being economically important for harboring significant amounts of nickel and copper sulfides. The main lithotypes of the complexes are gabbronorites, olivine gabbronorites, pyroxenites and peridotites, with variated degrees of deformation, recrystallization and metamorphism superimposed, with metamorphic peak of amphibolite to granulite facies evidenced mainly by the occurrence of coronitic olivine in metamafic rocks and the occurrence of syn-kinematic retrometamorphism associated with the development of the main foliation Sn. The Sn foliation planes show NE-SW preferential direction, consistent with the foliation direction of VIII the enclosing gneisses and schists, also concordant with the general elongation of mafic and ultramafic bodies displayed on map. The sulfide phase presents textures that indicate remobilization, associated with the occurrence of significant amounts of rutile within the ore which reinforces this idea. Along with the sulfides, the occurrence of expressive quantities of titanium oxides such as ilmenite and rutile, make the area more economically attractive. It can be suggested that the Mangabal Norte and Mangabal Sul complexes are contemporary, have the same genetic affinity and suffered the same deformational and metamorphic processes, evidenced by their structural and petrological similarities

Caracterização estrutural da mineralização da mina de Fazenda Nova - GO

The study area is includes in the geological context of Arenópolis Magmatic Arc, a region where there are neoproterozoic associations of granodioritic and tonalitic composiotion. (Ortogneisses of the western Goiás) and sequences metavolcanic-sedimentary (Jaupaci Metavolcanic-sedimentary Sequence ). In the mapped area, both units are covered by a cover-laterite. The Ortogneisses from Goiás West consist of a source granodioritic gneisses, corresponding to the Biotite granodiorite gneisse, and also by tonalitic gneiss composition corresponding to Metatonalit. The Jaupaci Metavolcanic-sedimentary Sequence is formed by Chlorite Schist (Metabasalt), Biotite Schist (Metadacite) and Sericite Schist (Metarhyolite), and even intrusions Sin/Tardi e Post Tectonic, granite to diorite composition (Diorites), and alson tonalitic (Bacilandia Tonalite). Post tectonic intrusions are observed, wich were Hornblend Diorite Porphyry and Lamprophyres, Structural analysis allowed the identification of three deformational events, Dn-1, Dn and Post-Dn. The first event is associated with a bygone foliation, lineation which generates an intersectional event, generating the foliation Sn, this being the most important structure in the study area, generating even the type mineral lineation and stretch. The last deformational event is characterized by folds on different scales, affecting the Sn foliation. The rocks of the region have features s active hydrothermal and regional metamorphism, and are composed os assembly indicative of mineralogical facies metamorphism Green Schist, in chlotite zone, with evidence of retro metamorphism. Locally there are sulfides as pyrite, arsenopyrit and pyrhotite, and te mineralization is associated with the arsenopyrite

A critical comparison of different approaches to sediment-quality assessments in the Santos estuarine system in Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização geofísica no Gabro Santa Catarina, São Sepé (RS)

Geophysical methods are widely used in mineral exploration for several types of mineral deposits. When combined with direct studies as geochemistry, a substantial increase in the probability of ore discovery is possible in mineral exploration activities. Electrical geophysical methods are particularly promising in studies related to the search of sulphides due to the contrast of physical properties electric resistivity and chargeability. This paper presents the results obtained from the application of Resistivity (DC) and Induced Polarization methods, through the electrical profiling technique, aiming at evaluating the potential mineral of a gabbro intruded in a metasedimentary sequence, in an area where several occurrences of gold and copper were described. This gabbro is ranked on the Basic-Ultrabasic stratiform bodies, which gather peridotites, gabbros, and layered anortosites. Three radial lines of electrical profiling were performed, spaced of 60° and crossing at the area center, with readings of electric resistivity and chargeability in Wenner-Schlumberger array. The association of low resistivity and high chargeability areas has allowed defining potentially mineralized zones related to structures that condition the drainage net in the gabbro domain. Grains of gold detected through geochemical prospection of alluvial sediments dowstream from the gabbro may have originated from leaching of ores deposited in fractures through the action of river waters within the gabbro domain, possibly consisting of sulphides and gold.

Avaliação de contaminação com óleo diesel por meio dos métodos de Eletrorresistividade e Polarização Induzida em Santa Ernestina-SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Integração de dados geofísicos e geológicos na caracterização morfológica de ocorrência de cobre na borda norte da Bacia do Camaquã (RS)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identificação taxonômica e análise conexionista de bactérias heterotróficas e fatores abióticos de ambientes lóticos sob influência de efluentes do refino no petróleo

This study used a multi-analytical approach based on traditional microbiological methods for cultivation and isolation of heterotrophic bacteria in the laboratory associated with the molecular identification of the isolates and physicochemical analysis of environmental samples. The model chosen for data integration was supported by knowledge from computational neuroscience, and composed by three modules: (i) microbiological parameters, contemplating taxonomic data obtained from the partial sequencing of the 16S rRNA gene from 80 colonies of heterotrophic bacteria isolated by plating method in PCA media. For bacterial colonies isolation were used water samples from Atibaia and Jaguarí rivers collected at the site of water captation for use in effluent treatment, upstream from the entrance of treated effluent from the Paulínia refinery (REPLAN/Petrobras) located in the Paulínia-SP municipality, from the output of the biological treatment plant with stabilization pond and from the raw refinery wastewater; (ii) chemical parameters, ending measures of dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), chloride, acidity CaCO3, alkalinity, ammonia, nitrite, nitrate, dissolved ions, sulfides, oils and greases; and (iii) physical parameters, comprising the pH determination, conductivity, temperature, transparency, settleable solids, suspended and soluble solids, volatile material, remaining fixing material (RFM), apparent color and turbidity. The results revealed interesting theoretical relationships involving two families of bacteria (Carnobacteriaceae and Aeromonadaceae). Carnobacteriaceae revealed positive theoretical relationships with COD, BOD, nitrate, chloride, temperature, conductivity and apparent color and negative theoretical relationships with the OD. Positive theoretical relationships were shown between Aeromonadaceae and OD and nitrate, while this bacterial family showed negative theoretical...