Caracterização da Alteração Hidrotermal Micácea do Tipo Greisen e dos Reequilíbrios de Baixa Temperatura em Áreas Graníticas: o Exemplo do Distrito Estanífero de Encruzilhada do Sul, RS

The hydrothermal alteration associated with the tin mineralization in the Encruzilhada do Sul Tin District is characterized by zones with different compositions. The most important of these hydrothermal zones are the phyllic and the argillic. The first one is composed mainly by white mica and quartz with tourmaline. The argillic alteration is composed by kaolinite. The phyllic zones represent associations with greisens and disseminated pervasive white mica on the granitic wall rocks. The argillic zones are constrained to the top zones of some granitic intrusions associated with greisens and quartz-veins in the stockworks. The hydrothermal fluids associated with the alteration show homogenization temperatures ranging from about 450˚C to 120˚C. The first temperature is the upper limit for the hydrothermal system, related with the white mica high temperature alteration. The second temperature is the lower limit of the argillic alteration under the hydrothermal conditions. The white mica related with the phyllic alteration range from phengite to muscovite. The argillic alteration has the presence of halloysite, probably as a weathering product.The hydrothermal alteration associated with the tin mineralization in the Encruzilhada do Sul Tin District is characterized by zones with different compositions. The most important of these hydrothermal zones are the phyllic and the argillic. The first one is composed mainly by white mica and quartz with tourmaline. The argillic alteration is composed by kaolinite. The phyllic zones represent associations with greisens and disseminated pervasive white mica on the granitic wall rocks. The argillic zones are constrained to the top zones of some granitic intrusions associated with greisens and quartz-veins in the stockworks. The hydrothermal fluids associated with the alteration show homogenization temperatures ranging from about 450˚C to 120˚C. The first temperature is the upper limit for the hydrothermal system, related with the white mica high temperature alteration. The second temperature is the lower limit of the argillic alteration under the hydrothermal conditions. The white mica related with the phyllic alteration range from phengite to muscovite. The argillic alteration has the presence of halloysite, probably as a weathering product

Quantification of coal char and coke fines in the off-gas blast furnace samples by X-ray diffraction

A difração de raios X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar o tamanho dos cristalitos (Lc ) dos materiais carbonosos. Este trabalho tem por objetivos identificar e quantificar os componentes carbonosos (char e finos de coque) presentes no pó de balão do Alto-forno (AF) pelas técnicas de DRX e de análise elementar de carbono. As partículas coletadas no pó de balão do AF, compostas por char, finos de coque e outros, foram fracionadas e analisadas quimicamente. Posteriormente, as frações foram moídas, desmineralizadas e analisadas por DRX. Amostras de char produzidas em laboratório e coque foram utilizadas como padrões para a quantificação. A técnica utilizada revela as diferenças na dimensão dos cristalitos destes materiais carbonosos, que a estrutura do coque é mais ordenada que a estrutura do char. Com base nessas diferenças podem-se quantificar as proporções de char e finos de coque no pó de balão do AF. A DRX permite quantificar, para o pó de balão em estudo, que 93% da matéria carbonosa se encontra na forma de coque e 7%, na forma de char. Palavras-chave: Char; Coque; Difração de raios X; Injeção de carvão pulverizado.X-ray diffraction (XRD) is a standard technique of characterizing structure of materials. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the off-gas blast furnace (BF) through the use of the XRD technique and ultimate analysis. The dust collected in the off-gas BF, which contains char, coke fines, metallic oxides, etc., was fractioned and chemically analyzed. In addition, the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. This technique reveals differences in crystallite size of the carbonaceous materials. The coke structure shows to be more ordered (bigger Lc ) than the char structure. Based on these differences, it is possible to quantify the fines proportions of char and coke in the blast furnace flue dust. The estimated char proportion in the carbonaceous material of the flue dust is 7%

Quantification of coal char and coke fines in the off-gas blast furnace samples by X-ray diffraction

A difração de raios X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar o tamanho dos cristalitos (Lc ) dos materiais carbonosos. Este trabalho tem por objetivos identificar e quantificar os componentes carbonosos (char e finos de coque) presentes no pó de balão do Alto-forno (AF) pelas técnicas de DRX e de análise elementar de carbono. As partículas coletadas no pó de balão do AF, compostas por char, finos de coque e outros, foram fracionadas e analisadas quimicamente. Posteriormente, as frações foram moídas, desmineralizadas e analisadas por DRX. Amostras de char produzidas em laboratório e coque foram utilizadas como padrões para a quantificação. A técnica utilizada revela as diferenças na dimensão dos cristalitos destes materiais carbonosos, que a estrutura do coque é mais ordenada que a estrutura do char. Com base nessas diferenças podem-se quantificar as proporções de char e finos de coque no pó de balão do AF. A DRX permite quantificar, para o pó de balão em estudo, que 93% da matéria carbonosa se encontra na forma de coque e 7%, na forma de char. Palavras-chave: Char; Coque; Difração de raios X; Injeção de carvão pulverizado.X-ray diffraction (XRD) is a standard technique of characterizing structure of materials. The aim of this work is to identify and quantify carbonaceous components (coal, char and coke fines) in the off-gas blast furnace (BF) through the use of the XRD technique and ultimate analysis. The dust collected in the off-gas BF, which contains char, coke fines, metallic oxides, etc., was fractioned and chemically analyzed. In addition, the fractions were grounded, demineralized and analyzed by ultimate analysis and XRD. This technique reveals differences in crystallite size of the carbonaceous materials. The coke structure shows to be more ordered (bigger Lc ) than the char structure. Based on these differences, it is possible to quantify the fines proportions of char and coke in the blast furnace flue dust. The estimated char proportion in the carbonaceous material of the flue dust is 7%

Caracterização da Alteração Hidrotermal Micácea do Tipo Greisen e dos Reequilíbrios de Baixa Temperatura em Áreas Graníticas: o Exemplo do Distrito Estanífero de Encruzilhada do Sul, RS

The hydrothermal alteration associated with the tin mineralization in the Encruzilhada do Sul Tin District is characterized by zones with different compositions. The most important of these hydrothermal zones are the phyllic and the argillic. The first one is composed mainly by white mica and quartz with tourmaline. The argillic alteration is composed by kaolinite. The phyllic zones represent associations with greisens and disseminated pervasive white mica on the granitic wall rocks. The argillic zones are constrained to the top zones of some granitic intrusions associated with greisens and quartz-veins in the stockworks. The hydrothermal fluids associated with the alteration show homogenization temperatures ranging from about 450˚C to 120˚C. The first temperature is the upper limit for the hydrothermal system, related with the white mica high temperature alteration. The second temperature is the lower limit of the argillic alteration under the hydrothermal conditions. The white mica related with the phyllic alteration range from phengite to muscovite. The argillic alteration has the presence of halloysite, probably as a weathering product.The hydrothermal alteration associated with the tin mineralization in the Encruzilhada do Sul Tin District is characterized by zones with different compositions. The most important of these hydrothermal zones are the phyllic and the argillic. The first one is composed mainly by white mica and quartz with tourmaline. The argillic alteration is composed by kaolinite. The phyllic zones represent associations with greisens and disseminated pervasive white mica on the granitic wall rocks. The argillic zones are constrained to the top zones of some granitic intrusions associated with greisens and quartz-veins in the stockworks. The hydrothermal fluids associated with the alteration show homogenization temperatures ranging from about 450˚C to 120˚C. The first temperature is the upper limit for the hydrothermal system, related with the white mica high temperature alteration. The second temperature is the lower limit of the argillic alteration under the hydrothermal conditions. The white mica related with the phyllic alteration range from phengite to muscovite. The argillic alteration has the presence of halloysite, probably as a weathering product

Role of compressive tectonics on gas charging into the Ordovician sandstone reservoirs in the Sbaa Basin, Algeria: constrained by fluid inclusions and mineralogical data

International audienc

Mineralogical Study of Levels with Magnesian Clay Minerals in the Santos Basin, Aptian Pre-Salt Brazil

The object of this study is magnesian clay minerals present in carbonate rocks of the post-rift phase of the pre-salt in the Santos Basin. These rocks developed in an Aptian-age alkaline lacustrine environment. This study summarizes the formation of clay minerals associated with different lithotypes in a range of 19 m and a depth of more than 5100 m. They were characterized from petrographic analysis by optical microscopy, X-ray diffraction (total sample and clay fraction), and modeling by Newmod®; and examined and analyzed by scanning electron microscopy. An approach based on identifying lithotypes and characterization of microsites allowed us to understand the occurrence of different clay minerals. Kerolite was the most abundant mineral in the sampled range. It occurs in lamellar aggregates under greater preservation of the original rock lamination and in association with spherulites and shrubs. The Stv/Ker mixed layers occurs in the same association, and formed finer unlaminated aggregates associated with the more intense dolomitization and silicification processes. Saponite occurs associated with detrital minerals forming clayey levels intercalated with microcrystalline carbonates. Fluids with a high Mg/Si and pH < 9 favor the precipitation of kerolite. The increase in pH during diagenesis may be responsible for the formation of Stv/Ker mixed layers