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  • 1
    Publication Date: 2021-11-11
    Description: Multi-stage deposition of metals from a sulfate solution with a high concentration of iron, aluminum, copper, zinc, and nickel has been studied. The concentrations of the components correspond to the composition of the sub-basement waters of the Gaisky GOK. Granular magnesia-silicate reagent based on serpentinite (Khalilovsk magnesite deposit, the Orenburg region, Russia) has been used as an alkaline agent. The magnesia-silicate reagent's ability to reduce the acidity of solutions is due to the presence of products of destruction of the original serpentine mineral, mainly magnesium oxide. The results of the solutions multi-stage purification from metals simulation have been presented. It has been found that the reagent did not wholly exhaust its activity during a single contact with the solution. Therefore, the possibility of its repeated use for the 2nd and 3rd time has been studied. As the solution is neutralized according to the known pH range of the beginning and complete deposition of metal compounds, first iron, and then aluminum are deposited. For copper and nickel, the effect of co-precipitation is observed until the pH of precipitation of poorly soluble compounds is reached. Iron is the main component of precipitations at the 1st, 2nd, and 3rd stages, which corresponds to pH = 2.4–3.7. At the 4th stage (pH = 4.0), the precipitations consisted mainly of aluminum compounds. The copper and nickel content in precipitations increase due to decreased concentration of major components (aluminum and iron) and a pH increase. The deposition of zinc from the solution occurs not to the precipitations, but on the granules surfaces. Precipitations enriched in aluminum and iron have been obtained. Sorption and co-precipitation processes have been observed for copper, zinc, and nickel, which prevents individual precipitation by these metals. Thermally activated serpentine minerals can be considered a promising alkaline reagent for technogenic solutions neutralization and purification.
    Description: Исследованы закономерности многоступенчатого осаждения металлов из сульфатного раствора с высоким содержанием железа, алюминия, меди, цинка и никеля. Концентрации компонентов соответствуют составу подотвальных вод Гайского ГОКа. В качестве щелочного реагента использован гранулированный магнезиально-силикатный реагент на основе серпентинитомагнезита (Халиловское месторождение магнезита, Оренбургская обл.). Способность магнезиально-силикатного реагента снижать кислотность растворов обусловлена наличием в нем продуктов разрушения исходного серпентинового минерала, преимущественно оксида магния. Смоделирован процесс многоступенчатой очистки растворов от металлов. Установлено, что реагент при однократном контакте с раствором не исчерпывает полностью свою активность, в связи с этим изучена возможность его многократного применения – во 2-й и 3-й разы. По мере нейтрализации раствора в соответствии с известным рядом рН начала осаждения соединений металлов происходит осаждение сначала железа, затем алюминия. Для меди и никеля наблюдается эффект соосаждения до достижения рН осаждения малорастворимых соединений. Основным компонентом осадков на 1-й, 2-й и 3-й ступенях, которым соответствует рН = 2,4–3,7, является железо. При рН = 4,0 (четвертая ступень) осадок состоит преимущественно из соединений алюминия. Содержание в осадках меди и никеля увеличивается в результате как уменьшения концентрации макрокомпонентов (алюминия и железа), так и повышения рН. Удаление цинка из раствора происходит не в осадок, а на поверхность гранул. Термоактивированные серпентиновые минералы могут быть использованы в качестве щелочного реагента для нейтрализации и очистки техногенных растворов. Получены осадки, обогащенные по алюминию и железу. Для меди, цинка и никеля наблюдаются процессы сорбции и соосаждения, что препятствует процессу образования данными металлами индивидуальных осадков.
    Description: Published
    Description: Refereed
    Keywords: Protection of underground waters ; Protection of surface waters ; Subsurface waters ; Highly concentrated solutions ; Purification of technogenic solutions ; Separate deposition of metals ; Magnesia-silicate reagent ; Serpentine ; Охрана подземных вод ; Охрана поверхностных вод ; Подотвальные воды ; Высококонцентрированные растворы ; Очистка техногенных растворов ; Раздельное осаждение металлов ; Магнезиально-силикатный реагент ; Серпентин ; ASFA_2015::M::Mining ; ASFA_2015::H::Heavy metals
    Repository Name: AquaDocs
    Type: Journal Contribution
    Format: pp.118-130
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  • 2
    Publication Date: 2020-02-12
    Description: Indications for the possible presence of a fluid accumulation below the drillbit of the KTB (German Continental Deep Drilling Project)‐Hauptbohrung are provided by comparisons of seismic P‐wave and S‐wave reflection sections. A bright reflection with negative polarity at approx. 8 km depth is seen only on P‐wave sections. It is absent on S‐wave sections in contrast to deeper reflections. This observation can be explained by the following geological models or combinations of them: (1) brine accumulation within a strongly fractured rock reservoir, (2) liquid/gas interface within strongly fractured rocks, (3) rock composition with increased quartz content and corresponding low Poisson's ratio, and (4) varying symmetry system of seismic anisotropy due to rock foliation. Predictions concerning the nature and location of this reflector are expected to be verified by drilling and direct probing in spring‐summer, 1993.
    Keywords: 550 - Earth sciences
    Type: info:eu-repo/semantics/article
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  • 3
    Publication Date: 2016-06-23
    Description: Rock-physics models are often needed to interpret fluid signatures from subsurface seismic data. Over the last decade or so, generalized fluid- and solid-substitution equations have been derived for estimating the exact change in seismic velocity or rock moduli upon changes in properties of quasisolids (e.g., heavy oil, bitumen, kerogen, ice, and salt) for the specified model conditions. However, these exact and mathematically elegant substitution equations fundamentally require details of rock microstructure, which are seldom known. Still, for problems involving solid or fluid substitution in rocks with heterogeneous pores, a rigorous solution range can be predicted using recently derived substitution bounds. These bounds only require total rock porosity, which can be inferred easily from geophysical data. In fact, Gassmann's equations are one of the lower bounds on the change in rock moduli upon fluid substitution, but, for solid substitution, Gassmann's predictions can be outside the bounds. Thus, for solid substitution, the lower bound itself is a better model than Gassmann. If additional microstructural parameters are known, it is possible to further constrain solid substitution or fluid substitution for heterogeneous rocks using the solid-squirt models. The solution range can be further constrained using additional effective moduli measurements of the same rock but filled with materials of varied elastic properties.
    Print ISSN: 1070-485X
    Electronic ISSN: 1938-3789
    Topics: Geosciences
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  • 4
    Publication Date: 2015-01-21
    Description: Prediction of sonic velocities in shales from well logs is important for seismic to log ties if the sonic log is absent for a shaly section, for pore pressure anomaly detection, and for data quality control. An anisotropic differential effective medium (DEM) was used to simulate elastic properties of shales from elastic properties and volume fractions of silt and wet clay (a hypothetical composite material that includes all clay minerals and water). Anisotropic elastic coefficients of the wet clay were assumed as a first-order approximation to be linearly dependent on wet clay porosity (WCP). Here, by WCP we mean a ratio of a pore volume occupied by water to a total volume of the wet clay. Effects of silt inclusions on elastic coefficients of shales were taken into account by using the anisotropic differential effective medium model. Silt inclusions were modeled as spherical quartz particles. Simulated elastic coefficients of shales were used to calculate compressional and shear velocities, and these were in a good agreement with the sonic velocities observed on a test data set from an offshore Mid-Norway well penetrating a 500-m vertical section of shale. To further study the elastic properties of wet clays, elastic coefficients calculated from compressional and sonic velocities measured in shales were inverted for vertical profiles of wet clay elastic coefficients. Analysis of these coefficients found that in the well considered, the increase in elastic coefficients of shales was controlled by the increase of silt fraction with depth. Elastic coefficients of wet clay found no increase with depth. The inverted elastic moduli of wet clay found much stronger correlation with WCP than do the moduli of shale. This confirmed the hypothesis that silt fraction is one of the key parameters for the modeling of elastic properties of shale.
    Print ISSN: 0016-8033
    Electronic ISSN: 1942-2156
    Topics: Geosciences , Physics
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  • 5
    Publication Date: 2016-02-27
    Description: Knowledge about the pressure dependency of elastic and electrical properties is important for a variety of geophysical applications. We present a technique to invert for the stiff and compliant porosity from velocity measurements made as a function of differential pressure on saturated sandstones. A dual porosity concept is used for dry rock compressibility and a squirt model is employed for the pressure and frequency dependent elastic properties of the rocks when saturated. The total porosity obtained from inversion shows satisfactory agreement with experimental results. The electrical cementation factor was determined using the inverted porosity in combination with measured electrical conductivity. It was found that cementation factor increased exponentially with increasing differential pressure during isostatic loading. Elastic compressibility, electrical cementation factor and electrical conductivity of the saturated rocks correlate linearly with compliant porosity, and electrical cementation factor and electrical conductivity exhibit linear correlations with elastic compressibility of the saturated rocks under loading. The results show that the dual porosity concept is sufficient to explain the pressure dependency of elastic, electrical and joint elastic-electrical properties of saturated porous sandstones.
    Keywords: Marine Geosciences and Applied Geophysics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 6
    Publication Date: 2016-02-26
    Description: Knowledge about the pressure dependency of elastic and electrical properties is important for a variety of geophysical applications. We present a technique to invert for the stiff and compliant porosity from velocity measurements made as a function of differential pressure on saturated sandstones. A dual porosity concept is used for dry rock compressibility and a squirt model is employed for the pressure and frequency dependent elastic properties of the rocks when saturated. The total porosity obtained from inversion shows satisfactory agreement with experimental results. The electrical cementation factor was determined using the inverted porosity in combination with measured electrical conductivity. It was found that cementation factor increased exponentially with increasing differential pressure during isostatic loading. Elastic compressibility, electrical cementation factor and electrical conductivity of the saturated rocks correlate linearly with compliant porosity, and electrical cementation factor and electrical conductivity exhibit linear correlations with elastic compressibility of the saturated rocks under loading. The results show that the dual porosity concept is sufficient to explain the pressure dependency of elastic, electrical and joint elastic-electrical properties of saturated porous sandstones.
    Keywords: Marine Geosciences and Applied Geophysics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 7
    Publication Date: 1966-01-01
    Print ISSN: 0009-3092
    Electronic ISSN: 1573-8310
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Springer
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  • 8
    Publication Date: 2014-06-04
    Description: Laboratory measurements of elastic and anelastic parameters of dry and water-saturated sandstones with low (0.7- and 1.1-mD) and high (425-mD) permeability have been conducted at seismic frequencies (0.1 to 120 Hz). The experiments were performed with a laboratory apparatus that measures the stress-strain relationship in the linear regime. The extensional attenuation in water-saturated low-permeability sandstones exhibits prominent peaks in the seismic band, accompanied by considerable dispersion. Variations in attenuation and dispersion in the high-permeability sandstone are below the measurement error, as is the moduli dispersion in all the sandstones in dry condition. The experiments demonstrate that for low-permeability rocks, seismic frequencies do not necessarily correspond to the low-frequency limit (relaxed pore-fluid pressures) of acoustic wave dispersion.
    Print ISSN: 1070-485X
    Electronic ISSN: 1938-3789
    Topics: Geosciences
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  • 9
    Publication Date: 2014-06-04
    Description: Seismic waves propagating in porous rocks saturated with two immiscible fluids can be strongly attenuated. Predicting saturation effects on seismic responses requires a sound understanding of attenuation and velocity dependencies on the fluid distribution. Decoding these effects involves interpreting laboratory experiments, analyzing well-log data, and performing numerical simulations. Despite striking differences among scales, flow regimes, and frequency bands, some aspects of wave attenuation can be explained with a single mechanism — wave-induced pressure diffusion. Different facets of wave-induced pressure diffusion can be revealed across scales.
    Print ISSN: 1070-485X
    Electronic ISSN: 1938-3789
    Topics: Geosciences
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  • 10
    Publication Date: 2012-12-16
    Description: The Hashin-Shtrikman (HS) bounds define the range of bulk and shear moduli of an elastic composite, given the moduli of the constituents and their volume fractions. Recently, the HS bounds have been extended to the quasi-static moduli of composite viscoelastic media. Because viscoelastic moduli are complex, the viscoelastic bounds form a closed curve on the complex plane. We analyze these general viscoelastic bounds for a particular case of a porous solid saturated with a Newtonian fluid. In our analysis, for poroelastic media, the viscoelastic bounds for the bulk modulus are represented by a semicircle and a segment of the real axis, connecting formal HS bounds that are computed for an inviscid fluid. Importantly, viscoelastic bounds for poroelastic media turn out to be independent of frequency. However, because the bounds are quasi-static, the frequency must be much lower than Biot’s characteristic frequency. Furthermore, we find that the bounds for the bulk modulus are attainable (realizable). We also find that these viscoelastic bounds account for viscous shear relaxation and squirt-flow dispersion, but do not account for Biot’s global flow dispersion, because the latter strongly depends on inertial forces.
    Print ISSN: 0016-8033
    Electronic ISSN: 1942-2156
    Topics: Geosciences , Physics
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