Vermiculite

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

The effect of hydrochemical conditions and pH of the environment on phyllosilicate transformations in the weathering zone of pyrite-bearing schists in Wieściszowice (SW Poland)

Abstract: The influence of hydrological conditions and the pH of the environment on chlorite and mica transformations in the acidic weathering zone of pyrite-bearing schists was studied. Phyllosilicate transformations were investigated in the area of the abandoned pyrite open-pit mine in Wieściszowice (Lower Silesia, SW Poland) using X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy and chemical methods. (Mg, Fe)-chlorite, micas (muscovite and paragonite), quartz, feldspars and pyrite were reported to be the most abundant minerals occurring in pyrite-bearing schists. Phyllosilicate transformations were significantly stronger in dry conditions than in wet ones. This conclusion was supported by the fact that the inherited phyllosilicates predominated in the clay mineral fraction of waterlogged saprolites, whereas the secondary swelling minerals were minor components. In dry and extremely acidic saprolites (pH < 3), trioctahedral chlorite was dissolved and transformed into clay minerals (e.g. smectite and kaolinite), whereas swelling clays (smectite mainly) were formed at the expense of dioctahedral micas. The pH of water is an important factor influencing phyllosilicate transformations in waterlogged conditions. The phyllosilicate alterations under the influence of extremely acidic waters (pH < 3) were more advanced than in moderately acidic ones (pH of 4.6), as the secondary clay minerals seemed to be represented exclusively by smectite in the former, whereas HIMs and mixed-layer minerals such as R0 I-S-Ch, R0 I-S, as well as R1 Ch-V and/or R1 Ch-S occurred in the latter.

Sterilizing water-purifying reagent for drink

Abstract: This invention provides a sterilizing water-purifying reagent for removing muddiness of water to be treated or sterilizing the water to be treated as drinking water in fields or under drinking water shortage environment, and the sterilizing water-purifying reagent comprises an acidic additive containing as main ingredients various types of metal salts and nonmetal salts produced by dissolving vermiculite weathered from mica mineral or soil further weathered from the vermiculite in aqueous inorganic acid solution.

An 57Fe Mössbauer spectral study of vermiculitization in the Palabora Complex, Republic of South Africa

Abstract: Two phlogopite, two mixed-layer phlogopite-vermiculite, and two vermiculite samples collected from the Palabora Complex of South Africa have been investigated at 295 K by X-ray diffraction, chemical analysis, and Mossbauer spectroscopy. In addition the temperature dependence of the Mossbauer spectra has been measured between 95 and 295 K for one phlogopite and one mixed-layer sample. The results of the chemical analyses and the Mossbauer spectra improve our knowledge of the vermiculitization process in the Palabora Complex. Both techniques indicate oxidation of the Fe ions during the sequence: phlogopite → mixed-layer → vermiculite. Further, the Mossbauer spectra indicate that Fe oxidation occurs mainly in the octahedral sites and suggest that migration and oxidation of the Fe2+ ions from the octahedral sites to the tetrahedral sites may occur during the transformation of phlogopite into a mixed-layer phase. Finally, the vermiculitization process involves both Fe oxidation and loss of K with a concomitant increase in the Mg content.

Desorption of Cesium Ions from Vermiculite with Sea Water by Hydrothermal Process

Abstract: Cesium ions (Cs+) strongly intercalated in vermiculite clay (Verm) had been effectively removed using sea water for its free utility, totally environmental friendly feature, and within containing n...

Potassium forms in calcareous soils as affected by clay minerals and soil development in Kohgiluyeh and Boyer-Ahmad Province, Southwest Iran

Abstract: Potassium (K) is known as one of the essential nutrients for the growth of plant species. The relationship between K and clay minerals can be used to understand the K cycling, and assess the plant uptake and potential of soil K fertility. This study was conducted to analyze the K forms (soluble, exchangeable, non-exchangeable and structural) and the relationship of K forms with clay minerals of calcareous soils in Kohgiluyeh and Boyer-Ahmad Province, Southwest Iran. The climate is hotter and drier in the west and south of the province than in the east and north of the province. A total of 54 pedons were dug in the study area and 32 representative pedons were selected. The studied pedons were mostly located on calcareous deposits. The soils in the study area can be classified into 5 orders including Entisols, Inceptisols, Mollisols, Alfisols and Vertisols. The main soil clay minerals in the west and south of the study area were illite, chlorite and palygorskite, whereas they were smectite, vermiculite and illite in the north and east of the province. Due to large amount of smectite and high content of organic carbon in soil surface, the exchangeable K in surface soils was higher than that in subsurface soils. It seems that organic matter plays a more important role than smectite mineral in retaining exchangeable K in the studied soils. Non-exchangeable K exhibited close relationships with clay content, illite, vermiculite and smectite. Although the amount of illite was the same in almost all pedons, amounts of structural and non-exchangeable K were higher in humid regions than in arid and semi-arid regions. This difference may be related to the poor reservoir of K+ minerals like palygorskite and chlorite together with illite in arid and semi-arid regions. In humid areas, illite was accompanied by vermiculite and smectite as the K+ reservoir. Moreover, the mean cumulative non-exchangeable K released by CaCl2 was higher than that released by oxalic acid, which may be due to the high buffering capacity resulting from high carbonates in soils.