Vermiculite

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

Mineralogical Composition and Weathering of Some Late Pleistocene Marine Clays from the Kongsvinger Area, Southern Norway

Abstract: The mineralogical composition was determined by using X-ray and thermal methods. The unweathered samples were composed of dioctahedral illite, chlorite, quartz, and feldspars. The following changes were observed as a function of weathering: chlorite → mixed-layer chlorite-vermiculite → vermiculite, and illite → mixed-layer illite-vermiculite with regular alternation of the two types of layers. The processes which are believed to take place during the weathering are described. The influence of weathering in postglacial times was observed to a depth of 3–4 m. In this zone an increase in ionic exchange capacities was observed as the depth decreased, due to the increasing content of vermiculite. The composition of exchangeable ions gradually changed, and the concentration of H+-ions also gradually increased with decreasing depth. The changes of the clay minerals caused an increase in activity and shear strength.

Acid activated montmorillonite and vermiculite clays as dehydration and cracking catalysts

Abstract: Treatment of montmorillonite and vermiculite with hydrochloric acid results in an overall increase in acidity and acidic sites. IR and DSC studies of base adsorbed catalysts have revealed the heterogeneity of surface acidity on the activated catalysts. Clay catalysts have been found to dehydrate 1-butanol to 1-butene, which directly isomerizes tocis- andtrans-2-butenes, confirming the presence of Lewis and Bronsted acid sites. Cumene cracking studies using the clay catalyst also confirm the presence of Bronsted acid sites. The temperature and concentration of acid have been found to have a significant influence on the catalytic activity.

Mineralogical composition of shallow soils on basic and ultrabasic rocks of East Fennoscandia and of the Ural Mountains, Russia.

Abstract: The influence of epigenetic (pre-pedogenetic) alteration of basic and ultrabasic rocks leading to the formation of phyllosilicate mineral associations is not well known The purpose of this study was to gain further understanding of the processes involved by investigating the mineral associations of shallow soils underlain by amphibolites and metamorphosed gabbro-diabases (East Fennoscandia) and by serpentinous dunites (olivinite) and metagabbro amphibolites (the Ural Mountains) Where phyllosilicates were absent from the bedrock, they were also absent from the sola The pedogenic alteration of the initial mineral soil matrix was very weak and did not result in a significant accumulation of phyllosilicates in the soils (East Fennoscandia) Pedogenesis enhanced the transformation of phyllosilicates, a process initiated by epigenic rock alteration Phyllosilicates in the sola from basic and ultrabasic rocks of the Polar Urals were largely inherited according to their origin The inherited phyllosilicate association of the sola from ultrabasic rocks included talc, serpentine, and chlorite Saponite resulted from pedogenesis; its distribution in various thin soils depending on the processes of neoformation and decomposition, the latter probably taking place under the influence of lichens and moss Chlorite and illite and products of their transformation, including vermiculite, comprise the phyllosilicate association of a solum from basic rock, and traces of talc were found The distribution of vermiculite and randomly interstratified chlorite-vermiculite (C-V) depended on the processes of chlorite vermiculitization and vermiculite decomposition