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Pedro José Sánchez-soto - One of the best experts on this subject based on the ideXlab platform.
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Phyllite clays as raw materials replacing cement in mortars: Properties of new impermeabilizing mortars
Construction and Building Materials, 2019Co-Authors: Carolina Arce, Eduardo Garzón Garzón, Pedro José Sánchez-sotoAbstract:Abstract The aim of this investigation was to determine the suitability of Phyllite clays as a raw construction material. For that purpose, the cement in mortars was replaced by a Phyllite clay (0–90 wt%) making this study the first of its kind to be performed. These materials were prepared with different water proportions according to the water content and water/cement and water/binder (cement plus Phyllite clay) relationships. A comparative study of the most important properties of the resulting experimental mortars was carried out, such as apparent density, water retentivity, consistency and mechanical strength (flexural and compressive strength), along with an evaluation of the pozzolanic activity and permeability. The results showed that the increase of Phyllite decreases the apparent density, the consistency and mechanical properties of the mortar, while water retentivity fluctuates. Good correlations (R 2 > 0.84) were obtained between flexural and compressive strength for the mortars after 28 days of curing. Pozzolanic activity was observed at cement replacement of 80 wt% of Phyllite. Moreover, new impermeabilizing mortars constituted by Phyllite clay and cement have been obtained according to the low coefficients of permeability. Taking into account the findings of this research, Phyllite clays can be applied as raw construction materials with savings derived from replacing cement in mortars and the low energy consumption involved in their production. However, the present study concluded that the use of Phyllite clays did not improve the mechanical strength of these new mortars but, in contrast, they can be applied for impermeabilization purposes in Construction and Civil Engineering.
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Effect of lime on stabilization of Phyllite clays
Applied Clay Science, 2016Co-Authors: Eduardo Garzón Garzón, Manuel Cano, Brendan Kelly, Pedro José Sánchez-sotoAbstract:Abstract This paper represents a new advance in the study of engineering properties and material applications of Phyllite clays. Considering their potential use as construction materials for structures subjected to low stress levels, this laboratory research investigated the stabilization and improvement in engineering properties of a Spanish Phyllite clay achieved by the addition of 3, 5 and 7 wt.% lime. Geotechnical properties investigated include the consistency limits, compaction, California Bearing Ratio, swelling potential and water-permeability. The Phyllite clay–lime mixtures had good compaction properties and very to extremely low permeability-coefficient values, with a semi-logarithmic correlation between increasing permeability and increasing proportion of lime additive. The addition of 3 wt.% lime was sufficient to reach the index of capacity amble specified in the Sheet of Technical General Prescriptions for Works of Roads and Bridges PG–3 (Spanish Highways Agency, 2008), significantly reducing the plasticity index value, with the compacted mixture undergoing no swelling under soakage. The required pavement thicknesses for the raw Phyllite–clay material and the Phyllite clay–lime mixtures are compared and discussed. Potential applications for Phyllite clay–lime mixtures include for pavements/road subgrade, earth construction, building materials and for impermeabilization purposes.
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Correlation between chemical and mineralogical characteristics and permeability of Phyllite clays using multivariate statistical analysis
Applied Clay Science, 2016Co-Authors: Eduardo Garzón Garzón, Enrique Romero, Pedro José Sánchez-sotoAbstract:Phyllite clays are applied as a layer on a surface to be waterproofed and subsequently compacted. For this purpose, Phyllite clays deposits can be grouped by their chemical and mineralogical characteristics, and these characteristics can be connected with their properties, mainly permeability, in order to select those deposits with the lowest permeability values. Several deposits of Phyllite clays in the provinces of Almeria and Granada (SE Spain) have been studied. The results of applying a multivariate statistical analysis (MVA) to the chemical data analysed from 52 samples determined by XRF, mineralogical analysis by XRD and permeability are reported. Permeability, a characteristic physical property of Phyllite clays, was calculated using the results for experimental nitrogen gas adsorption and nitrogen adsorption-desorption permeability dependence. According to the results, permeability values differentiated two groups, i.e. group 1 and group 2, with two subgroups in the latter. The influence of chemical as well as mineralogical characteristics on the permeability values of this set of Phyllite clays was demonstrated using a multiple linear regression model. Two regression equations were deduced to describe the relationship between adsorption and desorption permeability values, which support this correlation. This was an indication of the statistical significance of each chemical and mineralogical variable, as it was added to the model. The statistical tests of the residuals suggested that there was no serious autocorrelation in the residuals.
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Phyllite clay–cement composites having improved engineering properties and material applications
Applied Clay Science, 2015Co-Authors: Eduardo Garzón Garzón, Manuel Cano, Brendan C. O'kelly, Pedro José Sánchez-sotoAbstract:Abstract Phyllite clays contain clay minerals (chlorite, illite and mixed-layer illite smectite), quartz and feldspars. In this experimental laboratory study, new composites of Phyllite clay and cement (5, 7 and 9 wt.%) were prepared and tested to determine their Atterberg limits, dry density and optimum water content for modified Proctor (MP) compaction, California Bearing ratio, swelling potential after soakage in water, unconfined compressive strength (UCS) and water-permeability coefficient. From the mixes investigated, the composite with 5 wt.% cement was deemed most suitable for certain construction material applications, having a plasticity index of 10.5%, maximum dry density of 2.17 Mg/m3 and optimum water content of 8% for MP compaction (undergoing no swelling under soakage), a UCS of 0.74 MPa, and a very low permeability coefficient value of 7.4 × 10− 11 m/s. Potential material applications for these new composites include for building construction, roofs, and flexible pavements.
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Phyllites used as waterproofing layer materials for greenhouses crops in Spain: multivariate statistical analysis applied to their classification based on X-ray fluorescence analysis
X-Ray Spectrometry, 2009Co-Authors: Eduardo Garzón Garzón, I. García-rodríguez, Antonio Ruiz-conde, Pedro José Sánchez-sotoAbstract:The results are presented for the chemical characterization carried out with 53 raw material samples with phyllosilicates from outcrops located between the provinces of Almeria and Granada (SE Spain) in order to use them as waterproof layers under the floors of greenhouses. For this purpose, the samples have been studied by these techniques: X-Ray Diffraction (XRD), X-Ray Fluorescence (WDXRF), Scanning Electron Microscopy (SEM), chemical analysis by energy-dispersive X-Ray detection (EDX), and thermogravimetry. To isolate groups of Phyllite samples with similar chemical profiles and correlations between the samples, the WDXRF data (11 chemical elements) have been processed using the methodology of exploratory multivariate statistical analyses: cluster analysis, main-component analysis, and discriminating canon analysis. This study was performed as a screening test and as a means of finding similarities and correlations among all 53 Phyllite samples, allowing the isolation of groups of Phyllite samples with similar chemical profiles. The results indicate that the 53 Phyllite samples can be divided into two main groups. The first group is subdivided into two subgroups (1 and 2), one of which includes most of the samples. The latter is further classified into three blocks with the same chemical composition. This allows to search for the raw material with potentially the best waterproof characteristics within the five groups. The classification is of validity as a screening test for subsequent experimental determinations concerning the physical properties of these samples. Copyright © 2009 John Wiley & Sons, Ltd.
Eduardo Garzón Garzón - One of the best experts on this subject based on the ideXlab platform.
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Phyllite clays as raw materials replacing cement in mortars: Properties of new impermeabilizing mortars
Construction and Building Materials, 2019Co-Authors: Carolina Arce, Eduardo Garzón Garzón, Pedro José Sánchez-sotoAbstract:Abstract The aim of this investigation was to determine the suitability of Phyllite clays as a raw construction material. For that purpose, the cement in mortars was replaced by a Phyllite clay (0–90 wt%) making this study the first of its kind to be performed. These materials were prepared with different water proportions according to the water content and water/cement and water/binder (cement plus Phyllite clay) relationships. A comparative study of the most important properties of the resulting experimental mortars was carried out, such as apparent density, water retentivity, consistency and mechanical strength (flexural and compressive strength), along with an evaluation of the pozzolanic activity and permeability. The results showed that the increase of Phyllite decreases the apparent density, the consistency and mechanical properties of the mortar, while water retentivity fluctuates. Good correlations (R 2 > 0.84) were obtained between flexural and compressive strength for the mortars after 28 days of curing. Pozzolanic activity was observed at cement replacement of 80 wt% of Phyllite. Moreover, new impermeabilizing mortars constituted by Phyllite clay and cement have been obtained according to the low coefficients of permeability. Taking into account the findings of this research, Phyllite clays can be applied as raw construction materials with savings derived from replacing cement in mortars and the low energy consumption involved in their production. However, the present study concluded that the use of Phyllite clays did not improve the mechanical strength of these new mortars but, in contrast, they can be applied for impermeabilization purposes in Construction and Civil Engineering.
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Effect of lime on stabilization of Phyllite clays
Applied Clay Science, 2016Co-Authors: Eduardo Garzón Garzón, Manuel Cano, Brendan Kelly, Pedro José Sánchez-sotoAbstract:Abstract This paper represents a new advance in the study of engineering properties and material applications of Phyllite clays. Considering their potential use as construction materials for structures subjected to low stress levels, this laboratory research investigated the stabilization and improvement in engineering properties of a Spanish Phyllite clay achieved by the addition of 3, 5 and 7 wt.% lime. Geotechnical properties investigated include the consistency limits, compaction, California Bearing Ratio, swelling potential and water-permeability. The Phyllite clay–lime mixtures had good compaction properties and very to extremely low permeability-coefficient values, with a semi-logarithmic correlation between increasing permeability and increasing proportion of lime additive. The addition of 3 wt.% lime was sufficient to reach the index of capacity amble specified in the Sheet of Technical General Prescriptions for Works of Roads and Bridges PG–3 (Spanish Highways Agency, 2008), significantly reducing the plasticity index value, with the compacted mixture undergoing no swelling under soakage. The required pavement thicknesses for the raw Phyllite–clay material and the Phyllite clay–lime mixtures are compared and discussed. Potential applications for Phyllite clay–lime mixtures include for pavements/road subgrade, earth construction, building materials and for impermeabilization purposes.
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Correlation between chemical and mineralogical characteristics and permeability of Phyllite clays using multivariate statistical analysis
Applied Clay Science, 2016Co-Authors: Eduardo Garzón Garzón, Enrique Romero, Pedro José Sánchez-sotoAbstract:Phyllite clays are applied as a layer on a surface to be waterproofed and subsequently compacted. For this purpose, Phyllite clays deposits can be grouped by their chemical and mineralogical characteristics, and these characteristics can be connected with their properties, mainly permeability, in order to select those deposits with the lowest permeability values. Several deposits of Phyllite clays in the provinces of Almeria and Granada (SE Spain) have been studied. The results of applying a multivariate statistical analysis (MVA) to the chemical data analysed from 52 samples determined by XRF, mineralogical analysis by XRD and permeability are reported. Permeability, a characteristic physical property of Phyllite clays, was calculated using the results for experimental nitrogen gas adsorption and nitrogen adsorption-desorption permeability dependence. According to the results, permeability values differentiated two groups, i.e. group 1 and group 2, with two subgroups in the latter. The influence of chemical as well as mineralogical characteristics on the permeability values of this set of Phyllite clays was demonstrated using a multiple linear regression model. Two regression equations were deduced to describe the relationship between adsorption and desorption permeability values, which support this correlation. This was an indication of the statistical significance of each chemical and mineralogical variable, as it was added to the model. The statistical tests of the residuals suggested that there was no serious autocorrelation in the residuals.
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Phyllite clay cement composites having improved engineering properties and material applications
Applied Clay Science, 2015Co-Authors: Eduardo Garzón Garzón, M Cano, Brendan C Okelly, P J SanchezsotoAbstract:Abstract Phyllite clays contain clay minerals (chlorite, illite and mixed-layer illite smectite), quartz and feldspars. In this experimental laboratory study, new composites of Phyllite clay and cement (5, 7 and 9 wt.%) were prepared and tested to determine their Atterberg limits, dry density and optimum water content for modified Proctor (MP) compaction, California Bearing ratio, swelling potential after soakage in water, unconfined compressive strength (UCS) and water-permeability coefficient. From the mixes investigated, the composite with 5 wt.% cement was deemed most suitable for certain construction material applications, having a plasticity index of 10.5%, maximum dry density of 2.17 Mg/m3 and optimum water content of 8% for MP compaction (undergoing no swelling under soakage), a UCS of 0.74 MPa, and a very low permeability coefficient value of 7.4 × 10− 11 m/s. Potential material applications for these new composites include for building construction, roofs, and flexible pavements.
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Phyllite clay–cement composites having improved engineering properties and material applications
Applied Clay Science, 2015Co-Authors: Eduardo Garzón Garzón, Manuel Cano, Brendan C. O'kelly, Pedro José Sánchez-sotoAbstract:Abstract Phyllite clays contain clay minerals (chlorite, illite and mixed-layer illite smectite), quartz and feldspars. In this experimental laboratory study, new composites of Phyllite clay and cement (5, 7 and 9 wt.%) were prepared and tested to determine their Atterberg limits, dry density and optimum water content for modified Proctor (MP) compaction, California Bearing ratio, swelling potential after soakage in water, unconfined compressive strength (UCS) and water-permeability coefficient. From the mixes investigated, the composite with 5 wt.% cement was deemed most suitable for certain construction material applications, having a plasticity index of 10.5%, maximum dry density of 2.17 Mg/m3 and optimum water content of 8% for MP compaction (undergoing no swelling under soakage), a UCS of 0.74 MPa, and a very low permeability coefficient value of 7.4 × 10− 11 m/s. Potential material applications for these new composites include for building construction, roofs, and flexible pavements.
Natalia Sawicka - One of the best experts on this subject based on the ideXlab platform.
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Adsorption of Eu(III) onto bentonite and Phyllite: A comparative study
Applied Clay Science, 2019Co-Authors: Joanna Kyzioł-komosińska, Janusz Janeczek, Monika J. Fabiańska, Tomasz Krzykawski, Aniela Matuszewska, Agnieszka Dzieniszewska, E. Teper, Magdalena Pająk, Natalia SawickaAbstract:Abstract Disposal of radioactive wastes in underground repositories necessitates knowledge on adsorption and mobility of radionuclides in host rocks (geologic barrier) and in engineered barriers, including clay barrier. The batch adsorption of Eu(III) (a homologue for trivalent radionuclides) onto Phyllite compared to bentonite was studied as a function of solution pH (4.5 and 7.0), solution to clay rock ratio (10:1, 100:1, 500:1 and 1000:1), and various Eu(III) concentrations (0.01–190 mg/L; 0.658 × 10−7–1.25 × 10−3 M). The experimental data were interpreted using the isotherm models of Langmuir, Freundlich, Dubinin-Radushkevich, Toth, and Sips. Adsorption/desorption experiments and bonding strength calculations showed that the adsorption behavior depends on the mineral composition of sorbents, solution pH, the initial concentration of Eu(III), and liquid: solution ratio (L:S). The cation exchange within the interlayer space of montmorillonite is the main adsorption mechanism in bentonite. Cation exchange on the minerals surface, chemical reactions leading to the precipitation of new phases, the electrostatic effect at a low initial concentration of Eu (III), and pH > pHPZC are adsorption mechanisms in Phyllites. Solution pH has a pronounced effect on the Eu(III) adsorption onto Phyllite due to surface protonation. Fe-oxides and hydroxides play a significant role in the adsorption/desorption of Eu(III) on Phyllites. The best fitting was obtained for three-parameter isotherm models of Sips and Toth. The mechanism of Eu(III) binding is complex and does not follow the ideal monolayer adsorption. While the maximum adsorption capacity of Phyllite is 2.5 to 6.6 times lower than of bentonite, depending on the solution pH, it is high enough to guarantee efficacious and durable removal of actinides from the contaminated solutions, particularly at their low concentrations. Phyllites adsorption and mechanical properties make them suitable additives to bentonite in a clay barrier.
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Mineralogy and organic geochemistry of Phyllite from the Dewon–Pokrzywna deposit, the Opava Mountains (SW Poland)
Geological Quarterly, 2018Co-Authors: Natalia Sawicka, Janusz Janeczek, Monika J. Fabiańska, Krzysztof Bahranowski, Tomasz Krzykawski, Aniela MatuszewskaAbstract:Phyllites from the Dewon–Pokrzywna deposit in the Opava Mts., SW Poland, were investigated by XRD (Rietveld method), XRF, EPMA, SEM, and ATR-FTIR from the perspective of their potential usage as a buffer and/or backfill material in a geological repository of radioactive waste. Organic matter dispersed in the Phyllite matrix was analysed by GC-MS. Fine-grained Mg-Fe-muscovite (13 to 29 wt.%), Fe-ripidolite (10 to 25 wt.%), detrital quartz (20 to 46 wt.%), and albite (7 to 28 wt.%) ± microcline, illite or illite/smectite, and kaolinite are major minerals in Phyllite samples. The chlorite/muscovite ratio ranges from 0.65 to 1.1. Mg-annite inherited from the precursor rock is a minor constituent. Detrital ilmenite is a dominant accessory mineral. Ancylite-(Ce) occurs in quartz-calcite-ripidolite veins. Two types of Phyllite have been distinguished based on the proportion of phyllosilicates to silt fraction: argillaceous (47 to 55 wt.% phyllosilicates) and silt-rich (28 wt.% phyllosilicates). Argillaceous Phyllite shows elevated content of alumina and moderate concentration of silica. It is highly enriched in Fe compared to Phyllites from other localities worldwide. The BET specific surface area of argillaceous Phyllite ranges from 1.73 to 3.64 m 2 /g. Whole-rock chemical composition, mineral assemblages, chlorite geothermometry, and the occurrence of aliphatic hydrocarbons suggest that argillaceous Phyllite originated from a pelagic pelite protolith under low-temperature (260–370°C) greenschist to subgreenschist facies conditions. Persistent biomarkers are indicative of bacterial degradation of planktonic organic matter suspended in a high water column. Enrichment in Fe-rich chlorite and Mg,Fe-muscovite, low volume of interconnected pores with dominant mesopores suggest that argillaceous Phyllite from the Dewon–Pokrzywna deposit is a potential candidate for a buffer and/or backfill material.
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mineralogy and organic geochemistry of Phyllite from the dewon pokrzywna deposit the opava mountains sw poland
Geological Quarterly, 2018Co-Authors: Natalia Sawicka, Janusz Janeczek, Monika J. Fabiańska, Krzysztof Bahranowski, Tomasz Krzykawski, Aniela MatuszewskaAbstract:Phyllites from the Dewon–Pokrzywna deposit in the Opava Mts., SW Poland, were investigated by XRD (Rietveld method), XRF, EPMA, SEM, and ATR-FTIR from the perspective of their potential usage as a buffer and/or backfill material in a geological repository of radioactive waste. Organic matter dispersed in the Phyllite matrix was analysed by GC-MS. Fine-grained Mg-Fe-muscovite (13 to 29 wt.%), Fe-ripidolite (10 to 25 wt.%), detrital quartz (20 to 46 wt.%), and albite (7 to 28 wt.%) ± microcline, illite or illite/smectite, and kaolinite are major minerals in Phyllite samples. The chlorite/muscovite ratio ranges from 0.65 to 1.1. Mg-annite inherited from the precursor rock is a minor constituent. Detrital ilmenite is a dominant accessory mineral. Ancylite-(Ce) occurs in quartz-calcite-ripidolite veins. Two types of Phyllite have been distinguished based on the proportion of phyllosilicates to silt fraction: argillaceous (47 to 55 wt.% phyllosilicates) and silt-rich (28 wt.% phyllosilicates). Argillaceous Phyllite shows elevated content of alumina and moderate concentration of silica. It is highly enriched in Fe compared to Phyllites from other localities worldwide. The BET specific surface area of argillaceous Phyllite ranges from 1.73 to 3.64 m 2 /g. Whole-rock chemical composition, mineral assemblages, chlorite geothermometry, and the occurrence of aliphatic hydrocarbons suggest that argillaceous Phyllite originated from a pelagic pelite protolith under low-temperature (260–370°C) greenschist to subgreenschist facies conditions. Persistent biomarkers are indicative of bacterial degradation of planktonic organic matter suspended in a high water column. Enrichment in Fe-rich chlorite and Mg,Fe-muscovite, low volume of interconnected pores with dominant mesopores suggest that argillaceous Phyllite from the Dewon–Pokrzywna deposit is a potential candidate for a buffer and/or backfill material.
Megan Hart - One of the best experts on this subject based on the ideXlab platform.
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Low-head hyperfiltration through Jurassic-Cretaceous metamorphic Darrington Phyllite discs (from the Northwest Cascades of Washington State, USA)
Hydrogeology Journal, 2013Co-Authors: Megan HartAbstract:El comportamiento de una membrana en sistemas que ocurren en la naturaleza o ingenieriles refiere a la restricción de la migración de un soluto a través de una membrana en relación con la migración del solvente. La hiperfiltración es el flujo neto que resulta cuando dos soluciones de diferente concentración son separadas por una membrana y se aplica una fuerza externa que excede la presión osmótica. Las membranas de arcillas que contienen estructuras en capas tienen una mayor eficiencia que las membranas con estructuras aleatorias. Por lo tanto, las rocas de baja permeabilidad con una estructura foliada deberían exhibir propiedades características de membrana. Se realizaron cuatro experimentos de infiltración sobre muestras de Darrington Phyllite del Easton Metamorphic Suite de las Cascadas Noroccidentales, Washington (EEUU). Las soluciones de cloruros fueron pasadas a través de discos delgados, intactos a cargas hidráulicas relativamente bajas. Al final de los experimentos las concentraciones de cloruro disuelto se incrementaron en 110–140 % y los coeficientes de reflexión calculados oscilaron de 0.87 a 0.88; esto fue atribuido al rechazo parcial del soluto por la filita. Los escenarios naturales en los cuales la filita puede exhibir propiedades características de las membranas incluyen (1) acuíferos someros colgados rodeados por filitas (2) acuíferos sobre presión limitados por filitas, (3) acuíferos limitados por filitas con flujos verticales de agua subterránea significativos, y (4) ultrafiltración durante la desvolatización metamórfica en profundidad. Los procesos propios de membranas exhibidos por la filitas pueden también contribuir a la formación de algunos cuerpos de minerales a baja temperatura. Un comportement de type membrane dans des systèmes naturels ou artificiels correspond à la limitation de la migration d’un soluté par rapport à celle du solvant à travers une membrane. L’hyperfiltration est le flux net qui se produit lorsque deux solutions de concentrations différentes sont séparées par une membrane et qu’une force extérieure supérieure à la pression osmotique est appliquée. Les membranes argileuses à texture stratifiée ont une meilleure efficacité que les membranes à texture non orientée. Par conséquent, des roches de faible perméabilité à texture foliée pourraient présenter des propriétés de membranes. Quatre expériences d’hyperfiltration ont été réalisées sur des échantillons de la Phyllite de Darrington du complexe métamorphique des Cascades du Nord-Ouest, Etat de Washington (USA). Des solutions de chlorure ont été passées à travers de fins disques intacts sous des charges hydrauliques relativement faibles. A la fin des expériences, les concentrations en chlorure dissous avaient augmenté de 110–140 % et les coefficients de réflexion calculés étaient de 0.87 à 0.88; ceci a été attribué à un rejet partiel du soluté par la Phyllite. Les scénarios naturels dans le cadre desquels une Phyllite pourrait présenter des propriétés de membrane sont les suivants (1) des aquifères superficiels perchés limités par une Phyllite, (2) des aquifères en surpression limités par une Phyllite, (3) des aquifères limités par une Phyllite avec des écoulements verticaux d’eau souterraine importants et (4) de l’ultrafiltration en profondeur au cours de la déshydratation métamorphique. Les processus membranaires présentés par la Phyllite pourraient aussi contribuer à la formation de certains corps minéralisés à basse température. O comportamento das membranas em sistemas naturais e de engenharia refere-se à restrição da migração de solutos através de uma membrana relativamente à migração do solvente. Hiperfiltração corresponde ao fluxo bruto que resulta quando duas soluções com diferentes concentrações são separadas por uma membrana e uma força externa é aplicada em excesso em relação à pressão osmótica. Membranas de argila contendo camadas sobrepostas têm eficiências superiores às membranas com fabrics aleatórios. Então, rochas de permeabilidade baixa com composição foliada podem exibir propriedades de membrana. Foram realizadas quatro experiências de hiperfiltração sobre amostras do Filito de Darrington, da Sequência Metamórfica de Easton, das Cascades Noroeste, Washington (EUA). Soluções de cloreto foram passadas através de discos finos intactos, a pressões hidráulicas relativamente baixas. No final das experiências, as concentrações de cloretos dissolvidos incrementaram 110–140 % e os coeficientes de refleção calculados variaram entre os 0.87 e os 0.88; isto foi atribuído à rejeição parcial de soluto pelo filito. Cenários naturais nos quais o filito pode exibir propriedades de membrana incluem (1) aquíferos suspensos subsuperficiais rodeados por filito, (2) aquíferos sob pressão rodeados por filito, (3) aquíferos rodeados de filito com fluxos verticais significativos, e (4) ultrafiltração durante devolatilização metamórfica em profundidade. Os processos de membrana exibidos pelo filito podem também contribuir para a formação de alguns corpos mineralizados de baixa temperatura. Membrane behavior in naturally occurring and engineering systems refers to the restriction of solute migration through a membrane relative to the migration of the solvent. Hyperfiltration is the net flux that results when two solutions of different concentration are separated by a membrane and an external force is applied in excess of the osmotic pressure. Clay membranes containing layered fabric have higher efficiencies than membranes with random fabrics. Therefore, low-permeability rocks with a foliated fabric might exhibit membrane properties. Four hyperfiltration experiments were conducted on samples of Darrington Phyllite from the Easton Metamorphic Suite of the Northwest Cascades, Washington (USA). Chloride solutions were passed through thin, intact discs at relatively low heads. At the end of the experiments, dissolved chloride concentrations had increased 110–140 % and calculated reflection coefficients ranged from 0.87 to 0.88; this was attributed to partial solute rejection by the Phyllite. Natural scenarios in which Phyllite might exhibit membrane properties include (1) shallow perched aquifers bounded by Phyllite, (2) overpressured aquifers bounded by Phyllite, (3) Phyllite-bounded aquifers with significant vertical groundwater flows, and (4) ultrafiltration during metamorphic devolatilization at depth. Membrane processes exhibited by Phyllite may also contribute to the formation of some low-temperature ore bodies.
Megan L. Hart - One of the best experts on this subject based on the ideXlab platform.
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Low-head hyperfiltration through Jurassic-Cretaceous metamorphic Darrington Phyllite discs (from the Northwest Cascades of Washington State, USA)
Hydrogeology Journal, 2012Co-Authors: Megan L. HartAbstract:Membrane behavior in naturally occurring and engineering systems refers to the restriction of solute migration through a membrane relative to the migration of the solvent. Hyperfiltration is the net flux that results when two solutions of different concentration are separated by a membrane and an external force is applied in excess of the osmotic pressure. Clay membranes containing layered fabric have higher efficiencies than membranes with random fabrics. Therefore, low-permeability rocks with a foliated fabric might exhibit membrane properties. Four hyperfiltration experiments were conducted on samples of Darrington Phyllite from the Easton Metamorphic Suite of the Northwest Cascades, Washington (USA). Chloride solutions were passed through thin, intact discs at relatively low heads. At the end of the experiments, dissolved chloride concentrations had increased 110–140 % and calculated reflection coefficients ranged from 0.87 to 0.88; this was attributed to partial solute rejection by the Phyllite. Natural scenarios in which Phyllite might exhibit membrane properties include (1) shallow perched aquifers bounded by Phyllite, (2) overpressured aquifers bounded by Phyllite, (3) Phyllite-bounded aquifers with significant vertical groundwater flows, and (4) ultrafiltration during metamorphic devolatilization at depth. Membrane processes exhibited by Phyllite may also contribute to the formation of some low-temperature ore bodies.
