The widespread Balıkesir bentonite deposits within the Miocene volcano-sedimentary units in western Anatolia have economic potential; they are important raw materials for the paper and bleaching industries in Turkey. No detailed geological, mineralogical, geochemical, or genesis characterizations of these bentonite deposits …
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Altered tephras (K-bentonites) are of great importance for calibration of the geologic time scale, for local, regional, and global correlations, and paleoenvironmental reconstructions. Thus, definitive identification of individual tephras is critical. Single crystal geochemistry has been used to differentiate tephra layers, and apatite is one of the …
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The X-ray diffraction patterns of the bentonites are presented in Fig. 2.In addition to montmorillonite, the divalent bentonite contains a notable quantity of palygorskite as illustrated in Table 1 and Fig. 2pared to other minerals, palygorskite is rare in nature, therefore very limited information available in the literature.
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Bentonites are clay rocks consisting predominantly of smectite. They form mainly from alteration of pyroclastic and/or volcaniclastic rocks. Extensive deposits, linked to large …
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Once optimized the kinetics time and bentonite concentration, either the effect of medium (i.e. pure water or 12%v/v EtOH in water) or the bentonites swelling were investigated. A specific protocol was adopted ( International Oenological Codex, 2015 ), that consists in dispersing 2 g of bentonite (previously dried at 80 °C for 12 h) into 90 mL ...
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K-bentonite and bentonite layers are the key components of a larger group of altered tephras that are useful for stratigraphic correlation and for interpreting the geodynamic evolution of our planet. Bentonites generally form by diagenetic or hydrothermal alteration under the influence of fluids with high-Mg content and that leach …
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Bentonite is a clay mineral with incredibly small particle sizes. This, in combination with the active chemistry on the surface of the particles (that makes them hold onto water), makes Bentonite the most plastic and impermeable common clay material used in ceramics. CAS Number: . EC Number: 215-108-5,
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To perform a complete chemical analysis of two Algerian bentonites Mag and Mos, k0-NAA and WDXRF techniques were used. The concentration values of thirty seven elements including ten rare earth elements (REE) have been determined. The k0-NAA results indicate that the concentration of trace elements is respectively 290 and 285 …
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The bentonites used in the experiment included two sodium bentonites from Wyoming and India and one calcium bentonite from Bulgaria (Table 1).The Indian and Bulgarian bentonites (grain size 0.5–3 mm) were ground to ensure homogeneity ( <0.2 mm), while the Wyoming bentonite was used as is because it was originally finer …
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bentonites. At Georgia Kaolin Company, he had positions as Director of Re-search, Manager of Operations, Vice President of Operations, and Execu-tive Vice President and Chief Operating Officer. Georgia Kaolin Company mined and processed kaolins in Georgia, sodium bentonites in Wyoming, cal-cium bentonites in Texas, and halloysite in New …
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The bentonites deposits are well known and have been exploited for a long time (since the 1960s), with the exception of Formosa bentonite. The economic potential and, especially, the interest in studying Formosa bentonite lies in its cation type (Mg 2+), which is scarcely described in the literature [5, 8, 10].
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Abstract The Ordovician–Silurian bentonite is an ideal target for probing complex geological events such as biological extinction, glaciations, and volcanic events at that time due to its global distribution and multiple intercalary strata. In this paper, Late Ordovician–Early Silurian K–bentonites from the western segment of the South …
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Pilot sites are currently used to test the performance of bentonite barriers for sealing high-level radioactive waste repositories, but the degree of mineral stability under enhanced thermal conditions remains a topic of debate. This study focuses on the SKB ABM5 experiment, which ran for 5 years (2012 to 2017) and locally reached a maximum …
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In the present study, dacite (PR1), perlite (PR2), moderately altered rocks (MPR), and Na- and Ca-bentonites were studied to describe and compare their …
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Some experimental parameters i.e. pH, bentonites dose, initial concentration and contact time have been used as a function to determine the capacity of bentonites to adsorb Zn 2+ ions. Different isotherm and kinetic model have been fitted. Textural and structural alteration of bentonites in presence of Zn 2+ ions was analysed in this ...
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Table 2 Approximate Amounts of Bentonite for Some Applications. Bentonite continues to rank second in quantity only to barite as a mud additive, as shown in Fig. 11-2.14 In spite of the partial replacement of bentonite by polymers in some muds, about 1,160,000 short tons (1,050,000 tonnes) of swelling-type bentonite, with a well-site cost …
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Definition: Bentonite is defined as a naturally occurring material that is composed predominantly of the clay mineral smectite. Most bentonites are formed by the alteration …
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By comparison, the free swelling ratio of bentonites before and after granulation is between 270% and 345%. From a statistical viewpoint, the average free swelling ratio of granular bentonite is 311.2% with a standard deviation of 0.17, while the average value for original bentonite is 311.8% and with a standard deviation of 0.20.
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This study analyzes the structure of microbial community in bentonites sampled from two deposits, i.e., the 10th Khutor (Russia) and Taganskoe (Kazakhstan) at different incubation temperatures (25 and 60°C). Bentonite from the 10th Khutor deposit reveals 10 phyla and 92 genera of bacteria upon incubation at 60°C, and 12 phyla and …
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The vG (1980) model has been used successfully to model the (S,psi) variation for bentonites (e.g. [3, 32]). It can be noted that the scatter in the figure is very high as the apparent air entry value can be observed to vary from 0.1 to 100 MPa. This is mainly due to the cumulative effect of multiple sources of uncertainty such as grades of ...
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Studies have shown that K-bentonites often display variations in layer charge and mixed-layer clay ratios and that these correlate with physical properties and …
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F e x content in bentonites ranged from 1.715 to 4.082 mg/kg with an average of 2.535 mg/kg. F f m is the fluorine absorbed by Fe, Mn, and Al oxides, oxyhydroxides, and hydrated oxides and precipitated with these chemicals, and ranged from 2.497 to 11.052 mg/kg with an average of 6.767 mg/kg.
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This chapter discusses the properties and uses of bentonite. Bentonites have a variety of uses in various industries. The properties of bentonites are contingent upon …
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Abstract. The pH of aqueous bentonite suspensions is known to be influenced by carbonates present even in minor amounts. On the other hand, at high solid:liquid …
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These stress-dependent temperature effects on swelling behavior of GMZ bentonite are further confirmed by data collected from literatures on various types (i.e., Ca- or Na-bentonite) of bentonites: regardless of the predominant cations, the elevation of temperature increased the swelling potential in the lower stresses part of SSL, whereas it ...
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This figure shows the values of GO and graphite content range from 0% to 50%, while values of the dry density of different compacted bentonites range from 1.4 Mg/m 3 to 1.9 Mg/m 3 in different researches. After …
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Bentonites are promising materials for electrochemical sensing because of their unique physicochemical properties. They have relatively high surface area, good adsorption and ion-exchange ability, highly tunable surface and interlayer composition, non-toxic nature, and excellent biocompatibility. Moreover, they are outstanding substrates …
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Abstract. Bentonite clay is one of the oldest clays that humankind has been using from ancient times as traditional habits and remedies. In recent years researchers have found many applications of ...
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El E m E n t s, Vol. 5, pp. 93–98 93 April 2009 ... INTRODUCTION Bentonites are clay rocks that form from volcanic glass and that consist predominantly of clay minerals of the smectite
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Therefore, under a given load, the 36 bentonites studied showed a significant range of resulting dry densities, depending on water content, CEC and porosity. In conclusion, for a given bentonite, the dry density after compaction explains some geotechnical parameters such as the swelling pressure.
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Bentonite is used in oenology to improve the limpidity and the stability of wine and to predict the formation of deposits in the bottle. The exchangeable cations in its lamellar structures strongly influence some properties, such as the specific surface, the exchange capacity and the adsorption behavior. The unintended use of bentonite for …
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The bentonite deposit is located in the mining district named Justina (Tolsa Minerales La Patagonia S.A.), at 87 km SE from Rincón de los Sauces city in Neuquén province and 9 km to the west of the paleontological site Auca Mahuevo (Jackson et al., 2013) (Fig. 1) and represents the first Na-bentonite deposit of Upper Cretaceous age …
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Bentonites, naturally occurring clays, are produced industrially because of their adsorbent capacity but little is known about their effects on human health. This manuscript reports on the effect of bentonites on cell growth behaviour. Bentonites collected from India (Bent-India), Hungary (Bent-Hungary), Argentina (Bent-Argentina), …
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These low-swelling bentonites can be activated by conventional soda-ash additions. The naturally high-swelling materials have undergone only partial calcification and do not require soda-ash modification. The relatively unaltered 'grey' or 'blue' bentonites have undergone little or no calcification. The latter have the highest Na to Ca ratios ...
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Bentonites are thin, widespread clay-altered ash layers that are commonly dominated by smectite ( Fisher and Schminke, 1984 ). This is the definition used by sedimentologists. Knight (1898) first used the name bentonite for an unusual clay in the Benton Shale of Cretaceous age in Wyoming. The absorbent properties and swelling …
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In the pursuit of new sources of aluminosilicates for alkaline cement manufacture, the present paper reports on the compositional and mineralogical assessment of the reactive potential of several types of bentonites. A number of factors affect strength development in these materials, in particular their potentially reactive silica and …
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Potentially toxic elements (PTEs) are an important type of pollutant, causing constant and far-reaching concerns around the world due to their increase in the mining …
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Bentonite and other clay rocks are of paramount importance in the field of environmental and waste management [14–32].Bentonites are a group of natural nanomaterials composed predominantly of crystalline mineral particles from the group of dioctahedral smectites—montmorillonite [33, 34].Bentonites from Slovak deposits …
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