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Vermiculite

About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.


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Journal ArticleDOI
TL;DR: In this article, low-grade metamorphic mineral associations present in mafic dikes from the Malaguide Complex were examined by X-ray diffraction (XRD) analysis, electron microprobe analysis (EMPA) and transmission-analytical electron microscopy (TEM/AEM).
Abstract: Low-grade metamorphic mineral associations present in mafic dikes from the Malaguide Complex were examined by X-ray diffraction (XRD) analysis, electron microprobe analysis (EMPA) and transmission-analytical electron microscopy (TEM/AEM). The low-grade phyllosilicates occur both as pseudomorphs after pyroxene and as matrix phases of the rock. The metamorphic phyllosilicate assemblage is formed either by chlorite + muscovite or by the association chlorite + randomly ordered chlorite/vermiculite mixed-layers + 1:1 regular chlorite/vermiculite mixed-layers + vermiculite (or Na-biotite). Chemical changes observed from chlorite to vermiculitic phases include: 1) increase of the Si/Al ratio; 2) decrease of Mg+Fe; and 3) presence of variable amounts of Ca+alkali. Later alteration of the second assemblage originates Al-smectite, which forms from chlorite-, mixed-layers- and low-charge biotite (vermiculite) packets. Excluding the alteration products, the mineral associations observed in dikes are similar, as studied by XRD, to those observed in metaclastites from this Complex, suggesting a common metamorphic event. Nevertheless, both EMPA and TEM/AEM analyses reveal chemical differences, which are probably related to differences in bulk-chemistry between metaclastites and dikes.

10 citations

Journal ArticleDOI
TL;DR: In this article, X-ray analysis of ten basaltic soil profiles was performed to identify the type and amount of each mineral present in each profile, and it was inferred that soil separates other than clay are contributing to the cationexchange capacity of these soils.
Abstract: Summary The clay separates (<2μ) isolated from the horizons of ten basaltic soil profiles are shown by X-ray analysis to have a mixedmineralogical composition; the type and amount of each mineral present being dependent on the drainage conditions within the profile. Kaolin, the end product of weathering, generally predominates in surface horizons. Vermiculite is formed in well-drained profiles, but where gleying symptoms are evident vermiculite is replaced by montmorillonite, the amount of which increases with increased degree of waterlogging. Illite occurs in only two profiles to any appreciable extent. It is inferred that soil separates other than clay are contributing to the cationexchange capacity of these soils.

10 citations

Journal ArticleDOI
01 Apr 2022-Geoderma
TL;DR: In this paper , the effects of clay mineral type and plant litter quality on soil respiration dynamics, and formation efficiency of SOM, physical fractions, and chemical and microbial compositions of SOM at the end of a 120-day incubation were determined.

10 citations

Journal ArticleDOI
12 Aug 2019-Minerals
TL;DR: In this paper, the results show that the structure of organo-vermiculite has a significant impact on the uptake of As(III) and As(V) anions.
Abstract: Among the various technologies tested for removing the anionic species resulting from arsenic contamination, sorption methods have received unflagging interest. Being potential sorbent materials, clay minerals modified by cationic surfactants are often examined for this purpose. Among the clay minerals tested, information regarding sorption properties of expanded vermiculite modified with surfactants is scarce. Therefore, the present study aims to prepare organo-vermiculites modified with hexadecyltrimethylammonium (HDTMA) and benzyldimethylhexadecylammonium (HDBA) at surfactant concentrations of 0.5, 1.0, and 2.0 cation exchange capacity. Modified sorbents were identified and characterized using the analytical methods that can determine phase composition and textural properties of the samples. The sorption of As(III) and As(V) as a function of initial pH value, initial concentration of As(III, V), and initial dosage of sorbent was investigated. The results show that HDTMA and HDBA affect the properties of raw vermiculite. For instance, increase in the concentration of surfactants is often accompanied by a change in interlayer space or textural properties of vermiculite. It was observed that tested organo-minerals adsorbed As(V) to a greater extent compared to As(III). Various analytical studies were carried out and the results revealed the successful synthesis of organo-vermiculite. Moreover, the study also showed that the structure of organo-vermiculite has a significant impact on the uptake of As(III) and As(V) anions.

10 citations

Patent
14 Aug 1979
TL;DR: A free-flowing, dry powder composition comprising vermiculite lamellae (delaminated vermiculus) is a free-flow, dry-powder composition with a solid particulate additive such as magnesium oxide as mentioned in this paper.
Abstract: A free-flowing, dry powder composition comprising vermiculite lamellae (delaminated vermiculite); preferably the composition contains a solid particulate additive such as magnesium oxide.

10 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202395
2022223
202163
202068
2019104
2018101