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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 paper , a mild and cost-efficient chemical route is developed to synthesize Si nanosheets from vermiculite via a preliminary chemical delamination assisted with low-temperature aluminothermic reduction in a eutectic molten salt system.

14 citations

Journal ArticleDOI
TL;DR: In this paper, acid-catalyzed Friedel-Crafts alkylation reactions of p-methylbenzyl chloride with benzene were carried out on four unmodified natural clay minerals.
Abstract: Acid-catalyzed Friedel–Crafts alkylation reactions of p-methylbenzyl chloride with benzene were carried out on four unmodified natural clay minerals. Phenyl-p-tolymethane was quickly and selectively formed in the presence of vermiculite. Although the specific surface area of vermiculite is smaller than those of the other clay minerals examined, such a characteristic property of vermiculite as a catalyst may be attributed to the absence of Bronsted acid sites and to the Lewis acid sites on the outer surface of vermiculite.

14 citations

Journal ArticleDOI
TL;DR: In this article, a mixed-layer (phlogopite-vermiculite) sample from Palabora, Republic of South Africa was used for K + ⇄ Ca 2+ exchange.
Abstract: K + ⇄ Ca 2+ exchange was performed on a mixed-layer (phlogopite-vermiculite) sample from Palabora, Republic of South Africa. Exchange isotherms, X-ray diffraction patterns and far infrared (FIR) spectra of the mineral were obtained. Different mineralogical phases were identified during the exchange process: K-vermiculite, Ca-vermiculite and a regular mixed-layer (V K -V Ca ) phase. Two types of exchange sites for K + were identified by FIR during the exchange process. The first type, dominant in the K-vermiculite, gives an absorption band at 76 cm -1 . The other, which was the most pronounced site in the mixed-layer phase, gives an absorption band at 72 cm -1 . The mixed-layer phase was formed only when oxidation of Fe 2+ resulted in the internal compensation of part of the negative charge of vermiculite. This study shows that the high selectivity displayed by vermiculite for K + is enhanced by the formation of the mixed-layer phase.

14 citations

01 Jan 1994
TL;DR: In this paper, a total of 34 loess-paleosol samples from the Luochuan and the Xifeng sections in the Loess Plateau, northern China, were separated into sand, silt and clay fractions, and their mineral compositions were analyzed.
Abstract: A total of 34 loess-paleosol samples from the Luochuan and the Xifeng sections in the Loess Plateau, northern China, were separated into sand, silt and clay fractions,and their mineral compositions were analyzed.Analytical results indicate that the loess and the paleosol have similar mineral components.They consist of quartz, mica,feldspar and chlorite,which amount to 80 to 91 percent,and minor amounts of kandit,smectite,vermiculite and some heavy minerals.Calcite,limonite and magnetite are not analyzed because they have been removed in sample preparation.The difference of mineral compositions in samples from different sections and stratigraphic levels is mainly the variation of the amount and grain size of minerals.The Luochuan section,the paleosol and the upper part of the same paleosol layer contain less feldspar and more mica and vermiculite with respect to the Xifeng section,to the loess and to the lower part of the same paleosol layer,respectively,indicating the coexistence of biochemically weathering process,which caused the textural change of minerals,and the physically weathering process,which resulted in the changes of the grain size of minerals,during the soil-forming process.This favors the soil-forming mechanism that the loess deposition and the soil formation take place simultaneously,with the soil developing as a result of greater rate soil formation.

14 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used vermiculite powder with low thermal conductivity to replace some of the fine aggregates in the asphalt mixture to lower the thermal conductivities of asphalt mixture.
Abstract: This study focused on the design of heat-resistant asphalt mixture for permafrost regions. Vermiculite powder with low thermal conductivity was used to replace some of the fine aggregates in the asphalt mixture to lower the thermal conductivity of asphalt mixture. Asphalt mixtures with different mass ratios (0, 3, 6, 9 and 12 %) of vermiculite powder were prepared for performance evaluation and thermal property evaluation. Wheel tracking test, low-temperature bending beam test, freeze–thaw splitting test and fatigue test were conducted to evaluate the influences of vermiculite powder on the high-temperature rutting resistance, low-temperature cracking resistance, moisture stability and anti-fatigue performance of asphalt mixture. Mathis TCI analyzer was used to analyze the influences of vermiculite powder on the thermal conductivity of asphalt mixture. Temperature monitor system was used to figure out the influences of vermiculite powder on the inside temperature of asphalt mixture. It is proved that vermiculite powder has no significant influences on the performances of asphalt mixture, while it obviously affects the thermal property of asphalt mixture. By the addition of 9–12 % vermiculite powder in asphalt mixture, the performances of asphalt mixture can still well meet the performance requirements for permafrost regions; the thermal conductivity can be reduced by 40–55 %; and the inside temperature of asphalt mixture can be lowered by 1–2 °C. It proves the feasibility of using vermiculite powder to produce heat-resistant asphalt mixture for permafrost regions.

14 citations


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