Showing papers on "Vermiculite published in 2003"

The Composition and Morphology of Amphiboles from the Rainy Creek Complex, Near Libby, Montana

Abstract: Thirty samples of amphibole-rich rock from the largest mined vermiculite deposit in the world in the Rainy Creek alkaline-ultramafic complex near Libby, Montana, were collected and analyzed. The amphibole-rich rock is the suspected cause of an abnormally high number of asbestos-related diseases reported in the residents of Libby, and in former mine and mill workers. The amphibole-rich samples were analyzed to determine composition and morphology of both fibrous and non-fibrous amphiboles. Sampling was carried out across the accessible portions of the deposit to obtain as complete a representation of the distribution of amphibole types as possible. The range of amphibole compositions, determined from electron probe microanalysis and X-ray diffraction analysis, indicates the presence of winchite, richterite, tremolite, and magnesioriebeckite. The amphiboles from Vermiculite Mountain show nearly complete solid solution between these end-member compositions. Magnesio-arfvedsonite and edenite may also be present in low abundance. An evaluation of the textural characteristics of the amphiboles shows the material to include a complete range of morphologies from prismatic crystals to asbestiform fibers. The morphology of the majority of the material is intermediate between these two varieties. All of the amphiboles, with the possible exception of magnesioriebeckite, can occur in fibrous or asbestiform habit. The Vermiculite Mountain amphiboles, even when originally present as massive material, can produce abundant, extremely fine fibers by gentle abrasion or crushing.

Biotite dissolution processes and mechanisms in the laboratory and in nature: Early stage weathering environment and vermiculitization

Abstract: Biotite dissolution in the laboratory and in nature was examined and compared to elucidate certain aspects of the weathering processes. Batch dissolution experiments of fresh biotite [(K 0 . 9 1 Na 0 . 0 1 )(Mg 0 . 4 0 Fe 2 . 0 7 Mn 0 . 0 5 Al 0 . 1 4 Ti 0 . 1 9 )(Si 2 . 8 2 Al 1 . 1 8 )O 1 0 (OH) 2 in granite were carried out at 150 °C for 1 to 56 days. Examination by scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS) revealed that, in the early stage, dissolution proceeds from the edges of crystals inward and secondary minerals such as Fe oxide are precipitated mostly at the edges, with only a few secondary minerals found on the basal surfaces. A dissolution experiment using a mixture of biotite and muscovite, done at 150 °C for 7 days, indicated that hematite crystals formed mostly at the edges of biotite but not on muscovite. This observation suggests that released Fe is precipitated before it diffuses into the bulk solution. Because a dissolution rate at the edge is larger by two orders of magnitude than at the basal surface (Turpault and Trotignon 1994), precipitation before diffusion of dissolved elements to bulk solution well explains the preferential secondary mineralization at the edges in the laboratory experiments. SEM-EDS of fresh to slightly weathered biotites revealed that early stage weathering proceeds in the same way as in the laboratory with the edges being preferentially weathered and secondary minerals being precipitated mostly at the edges. Because of the similarity between the occurrence of secondary minerals in the laboratory experiments and in nature, the laboratory results elucidate the early stage weathering conditions, namely that (1) supersaturation with respect to secondary minerals in a solution occurs around biotite, i.e., the solution is poorly connected to a main flow pathway of water, and (2) once supersaturation is achieved, secondary minerals are precipitated mainly at the edge before some released elements diffuse into the solution. The immobility of water immediately adjacent to primary minerals partly explains the large difference in dissolution rate between the laboratory and natural samples. A phlogopite dissolution experiment was done at 150 °C for 5.5 days to examine the effect of biotite composition on vermiculitization. High-resolution transmission electron microscopy revealed that vermiculite layers are formed by layer-by-layer transformation within phlogopite after 5.5 day dissolution but not within biotite after 56 day dissolution or within slightly weathered biotite. A comparison of our data with results of other studies indicates that the formation of vermiculite layers between biotite layers occurs even in the early stage when biotite is not Fe-rich [more than 0.8 Mg per O 1 0 (OH) 2 ]. When biotite is Fe-rich [less than 0.4 Mg per O 1 0 (OH) 2 ]-like the present one-released Fe is precipitated as, for example, Fe hydroxide, and vermiculite is rarely formed because of limited availability of Mg. Thus, a higher Mg content in biotite facilitates the formation of vermiculite, at least in the early stage. Because vermiculite dissolves at a much slower rate than biotite, Mg-rich biotite dissolves at a slower rate than Fe-rich biotite. In the late stage, biotite dissolution still continues from the edge and within biotite, which results in a fine comb-like texture for weathered biotite; vermiculite occurs as a domain within chemically and structurally altered biotite as well, as at the edge even during weathering of Mg-poor biotite.

Adsorption of Cadmium from Aqueous Solutions by Vermiculite

Abstract: The present study involves an investigation of a low-cost adsorbent, vermiculite for the removal of cadmium from aqueous solutions. The effects of pH and contact time on the adsorption process were examined. The optimum pH for adsorption was found to be 6. Residual cadmium concentration reached equilibrium in four hours and the rate of cadmium adsorption by vermiculite was rapid in the first hour of the reaction time. Ho's pseudo second order model best described the reaction rate. Batch adsorption experiments conducted at room temperature (22±1°C) showed that the adsorption pattern followed the Freundlich isotherm model. The maximum removal of cadmium obtained from batch studies was 96%. Thomas model was used to describe the adsorption data from column studies. Overall, the results showed that vermiculite could be considered as a potential adsorbent for cadmium removal from aqueous solutions.

Vermiculite — a Promising Material for High-Temperature Heat Insulators

Abstract: Vermiculite, a mineral of natural occurrence of the group of hydromicas, when heated to above 300°C, expands to become a highly efficient heat-insulating material. The expanded vermiculite, owing to its unique properties – low bulk density, low heat conductivity, relatively high melting point, chemical inertness, endurance, and environmental safety – can be used as a filler for heat-insulating materials. Heat insulators based on expanded vermiculite can be used in thermal power units with the hot-wall temperature not exceeding 1150°C as replacement for lightweight chamotte components and fibrous heat insulators.

Secondary Mineral Genesis from Chlorite and Serpentine in an Ultramafic Soil Toposequence

Abstract: The origin of secondary phyllosilicates in serpentinitic soils of differing moisture regimes is incompletely understood. The objective of this study was to determine the genesis of weathering products in serpentinitic soils along a moisture regime gradient using conventional x-ray diffraction (XRD) methods and high-resolution transmission electron microscopy (HRTEM), The samples studied were obtained from an Aquic Argixeroll and a Cumulic Endoaquoll on the Trinity ophiolite, in the Klamath Mountains, California. The soils are from backslope and toeslope landscape positions associated with a 3,2-ha wetland on a stabilized landslide bench. Chlorite and serpentine are the major primary minerals in the soils. Chlorite is relatively stable and was found in the clay fraction of all horizons studied. Serpentine was observed in all horizons except the Aquic Argixeroll Cr2 horizon. The soil mineral assemblages indicate that chlorite transforms to vermiculite and both randomly and regularly interstratified chlorite/vermiculite by loss of the hydroxide-interlayer Sheet. The vermiculite then alters to a high-charge smectite that was found only in the lower horizons of the backslope landscape position. Smectite is the predominant secondary mineral in all horizons, Serpentine transformation products could not be directly identified, but the prevalence of a low-charge smectite in the Cumulic Endoaquoll is interpreted as a precipitate from serpentine dissolution products. Thus, the abundant smectite in these serpentinitic soils is of two origins: (i) a high-charge phase derived from chlorite transformation that is found in the backslope landscape positions, and (ii) a low-charge phase neoformed by precipitation of elements released by serpentine weathering.

Study of natural and ion exchanged vermiculite by emanation thermal analysis, tg, dta and xrd

Abstract: Emanation thermal analysis (ETA), thermogravimetry, DTA and XRD were used in thermal characterization of natural vermiculite (Santa Olalla, Huelva, Spain) and of Na+- and - exchanged vermiculite samples during heating in air in the range 25-1100°C. A good agreement between the results of these methods was found. Changes in the radon release rate measured by ETA, which reflected the decrease and collapse of the interlayer space after the release of water as well as the formation of new crystalline phases were evaluated using a mathematical model. The model used for the evaluation was found suitable for the quantitative characterization of microstructure changes during in situ conditions of heating of vermiculite samples.

Adsorption of crude oil on anhydrous and hydrophobized vermiculite

Abstract: This publication reports the adsorption of crude oil on vermiculite samples, expanded and hydrophobized with carnauba (Copernicia Cerifera) wax. The adsorption studies were performed by using columns filled with the vermiculite matrices and by dispersion of the vermiculite samples in an oil-water (50 ppm of oil) emulsion. The hydrate vermiculite exhibits a very low adsorption capacity against crude oil. On the other hand, anhydrous (expanded) and hydrophobized matrices show a high adsorption capacity. The 10% hydrophobized matrix show a 50% increased adsorption capacity, in comparison with the expanded one. For adsorption performed in the water-oil emulsion, saturation of the solid hydrophobized matrix is achieved after 60 min. The hydrophobized samples exhibit adsorption factors in the 0.7-1.0 range.

Study of the dehydration process of vermiculites by applying a vacuum pressure: formation of interstratified phases

Abstract: Structural transformations between the different hydration states of three vermiculite samples from Sta. Olalla (Huelva, Spain), Paulistana (Piaui, Brasil) and West China, have been observed by X-ray diffraction at atmospheric pressure, P = 1.4610 ˇ2 mbar and P = 2.4610 ˇ4 mbar. The samples were studied in flake and powder forms. The effect of vacuum has been proven to be the same as that of temperature, i.e. it causes dehydration of vermiculite, but with a different evolution through the different hydration states. In fact, under vacuum, the process seems to be inhibited at a one-water layer hydration state (1-WLHS), without a further dehydration of samples to a zero-water layer hydration state (0-WLHS). Furthermore, the dehydration process has been shown to occur through different interstratified states in each vermiculite. This result has been related to the interlayer Mg-cation content, due to its affinity to water molecules. The interstratified states have been analysed by the direct Fourier-transform method. The vermiculite from Sta. Olalla exhibits the most complex process, with formation of three different interstratified phases: two phases characterized by an interstratification of interplanar

Effects of packing material on the biofiltration of benzene, toluene and xylene vapours.

Abstract: Biofiltration was used to eliminate volatile organic compounds from air streams in bench‐scale reactors inoculated with an adapted consortium. Organic and inert supports were tested on 100 days of operation. The supports were: peat, vermiculite, a mixture of vermiculite and activated carbon, tree bark and, porous glass Rashig rings. A mixture of benzene, toluene and xylene vapors with a load of 200 gC m−3 h−1 was fed to the biofilters with an empty bed residence time of 60 s. Removal efficiencies higher than 95% were obtained with the mixture of vermiculite and activated carbon, 85% for peat and bark, 80% for vermiculite and 65% for the Rashig rings. In all cases, drying problems in beds were observed after several days of operation. Water addition with or without nutrients was required to maintain and increase the performance of biofilters. In steady state operation, experiments at loads ranging from 50 to 400 gC m−3 h−1 were carried out and a maximum elimination capacity of 260 gC m−3 h−1 was o...

The 10 å to 7 å halloysite transition in a tropical soil sequence, costa rica

Abstract: Soils developed on Pleistocene andesitic lava flows and fluvial detritus in the Atlantic coastal plain of Costa Rica display a clay mineral assemblage that includes 10 A and 7 A halloysite and lesser amounts of kaolinite and dioctahedral vermiculite. Other secondary minerals include gibbsite, goethite, hematite, maghemite, allophane and amorphous Al hydroxides. Active floodplain soils are dominated by 10 A halloysite and contain less allophane, while soil clays from Pleistocene terraces consist of a mixture of 10 A and 7 A halloysite as well as less dioctahedral vermiculite, kaolinite, and amorphous Al hydroxides. Residual soils formed on Pleistocene lava flows are dominated by 7 A halloysite with less abundant kaolinite, dioctahedral vermiculite, 10 A halloysite and amorphous Al hydroxides. This sequence suggests transformations of 10 A halloysite to 7 A halloysite and allophane to amorphous Al hydroxides with time. The presence of 10 A halloysite in Pleistocene terrace soils implies slow reaction rates or metastability. Quantitative X-ray diffraction (QXRD) analysis indicates a decrease in the amount of plagioclase feldspar from 34 wt.% in the 1–2 year floodplain to 0–1.6% in terrace and residual soils. Plagioclase weathering is paralleled by the formation of dioctahedral clay, allophane and Al hydroxides. Analysis by QXRD also indicates that crystalline minerals comprise 70–95% of the soil fraction, implying 5–30% X-ray-amorphous material. These data are verified by selective extraction using ammonium oxalate, which indicates 8–30% amorphous material. Chemical analysis of the extractant by inductively coupled plasma-atomic emission spectrometry indicates that allophane (Al:Si ratios of 0.92–3.82) occurs in floodplain and some terrace soils while amorphous Al hydroxides appear to coexist with allophane in Pleistocene terrace and residual soils with Al:Si ratios of 6.53–8.53. Retention of Mg to a greater extent than Na, Ca and K suggests Mg incorporation into hydroxide sheets in dioctahedral vermiculite as well as substitution into hydroxides.

Mineralogy, chemistry, and formation of oxidized biotite in the weathering profile of granitic rocks

Abstract: Biotite was oxidized in deep saprolitic weathering profiles developed on granitic rocks in a humid temperate climate in the Youngju-Andong area of South Korea. The mineralogy and chemistry of these oxidized biotites were characterized by chemical analysis, electron microscopy, X-ray diffraction, thermal analysis, and radiogenic Ar analysis. The results showed that a decrease in the b o-dimension, loss of radiogenic Ar, and formation of vermiculite are fairly well correlated with the degree of oxidation of ferrous iron. The chemical composition of oxidized biotite was modified by a non-stoichiometric removal of interlayer and octahedral cations to compensate for the charge imbalance induced by oxidation of Fe. The pervasive loss of cations and radiogenic Ar suggests their diffusion through oxidizing biotite in a non-expanded state. Iron oxidation and cation loss caused a decrease in the b o-dimension with the formation of discontinuities that acted as conduits for the weathering solutions, resulting in partial vermiculitization (<10%). The Fe oxidation was nearly completed in the lower part of the profile, concomitant with mineralogical and chemical modification to oxidized biotite that persists throughout the profile without further notable modification. Cation release from biotite is governed in early stage by the formation of oxidized biotite, and later by its decomposition.

Microwave Exfoliation of Vermiculite and Phlogopite

Abstract: Vermiculites and phlogopites can be exfoliated by chemical and thermal treatment methods to obtain chemically inert, adsorbent, fire-resistant, low-density materials with excellent thermal and acoustic insulation properties. The water content of the clay generally determines the extent of exfoliation and the presence of interstratification is claimed to increase the rate of exfoliation. Considering the strong interaction between water and microwaves, the effect of microwave power on exfoliation characteristics of vermiculites and phlogopites after treatment with water and hydrogen peroxide solution were studied at 600, 950 and 1300 W for microwave exposure times of 10, 20, 30, 60, 120 and 300 s. It was observed that the water molecules in the interlayers of the individual flakes were driven off quickly by microwave treatment causing layer separation in the samples. The vermiculite sample showed 2.8 and 5.6 times, respectively, the exfoliation ratio of the phlogopite samples, in accord with their water contents.

Effect of the Si/Al ordering on structural parameters and the energetic stabilization of vermiculites – a theoretical study

Abstract: The effect of the Si/Al distribution in the tetrahedral sheets of the vermiculite mineral has been investigated employing density functional theory. The structures of six models for vermiculite with the structural formula (Mg4)(Mg12)(Si8Al8)O40(OH)8·24(H2O) per unit cell were fully optimized. The models differ by the T···Mg2+···T′ coordination of the interlayer Mg2+ cations by two central cations from the adjacent tetrahedral sheets of the 2:1 vermiculite layers (T,T′=Si,Al). We observed the formation of very strong hydrogen bonds between water molecules solvating the interlayer Mg2+ cations and the surface basal oxygen atoms of the 2:1 layers. The directionality of hydrogen bonds is the major factor determining the layer stacking in the vermiculite structure. Results showed that the most stable model is that where only silicon atoms in the tetrahedral sheets coordinate all interlayer Mg2+ cations.

Experimental alteration of Mg-vermiculite under hydrothermal conditions: formation of mixed-layered saponite-chlorite minerals

Abstract: The hydrothermal reactivity of a Mg-vermiculite from Santa Olalla (Spain) was studied experimentally at 150 and 300oC, 75 and 100 bars, respectively, in (Na,K,Ca,Mg) chloride and sulphate solutions (liquid/solid ratio = 10) The formation of mixed-layer clays is demonstrated by FT-IR spectroscopy, X-ray diffraction (XRD) and electron microprobe The gradual decrease of the 3220 cm–1 infrared band intensity, characteristic of free water, is interpretated as the dehydration of the interlayer Mg cation of the vermiculite The presence of ‘brucite type’ sheets is also observed by the increase of 3555 cm–1 and 3420 cm–1 band intensities The XRD results show that run products are able to expand when glycolated Microprobe analyses document the decrease of IVSi content and a significant enrichment in Mg in the run products The formation of a mixed-layer clay comprising saponite and chlorite layers is proposed

Plasterboard composition, preparation of this composition and manufacture of plasterboards

Abstract: A plasterboard composition includes from 55 to 92% of hydratable calcium sulphate; from 01 to 5% of mineral and/or refractory fibres; from 3 to 25% of a mineral additive; from 1 to 5% of unexpanded vermiculite; and from 3 to 15% of hydrated alumina

Enraizamento de estacas lenhosas de pessegueiro cv. Okinawa em diferentes diâmetros de ramos, substratos e recipientes

Abstract: This work was carried out at the Department of Plant Production/Horticulture of the Faculdade de Ciencias Agronomicas (FCA) of the Universidade Estadual Paulista (UNESP) located in Botucatu (SP, Brazil). The purpose of this study was to evaluate the influence of substrate and pot type on rooting of stem hardwood cuttings of peach cultivar Okinawa with different diameters. The cuttings were treated with 2.5g L-1 of IBA. The cuttings were maintained in greenhouse for 50 days. The treatments consisted of the combination of six substrate compositions: sand, carbonized rice husk, vermiculite, sand + carbonized rice husk, sand + vermiculite, and carbonized rice husk + vermiculite, mixture at proportion 1:1v/v and three types of pots: plastic bags, polystyrene trays, plastic trays and two groups of cutting diameter: 2 to 6mm and 6 to 10mm. The highest rooting frequency was obtained with plastic bag, and vermiculite independent of cutting diameter.

Composition for building material

Abstract: PROBLEM TO BE SOLVED: To provide a building material which more effectively utilizes vermiculite as a natural resource, can satisfy the demand of humidity conditioning and/or deodorizing and further of beautiful appearance, is excellent in balance between amount and speed of moisture absorption/release in particular and further has improved bending strength, flexibility and productivity. SOLUTION: A composition for the building material is prepared by blending unswollen vermiculite with a base material selected from one or more kinds of cement, calcium silicate and slag gypsum, wherein the blending amount of the unswollen vermiculite is 0.5-70 mass% of the total composition (solid content). The composition is characterized in that the unswollen vermiculite of ≤300 μm is 0.5-15 mass% of the total composition (solid content). COPYRIGHT: (C)2007,JPO&INPIT

Metamorphic chlorite and “vermiculitic” phases in mafic dikes from the Maláguide Complex (Betic Cordillera, Spain)

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.

The influence of exchangeable cation on thermal behaviour of ground vermiculite

Abstract: Grinding and contact with water or salt solution increased the specific surface (ssa) but lowered the first dehydration effect (escaping up to 150°C) and increased the second dehydration effect (150 to 500°C). The dehydroxylation was moved to lower temperatures and was only ΔM(500-1100°C)=3.7±0.3 % as compared to 5.5% in the parent vermiculite (V). Except ΔM(20-150°C), the mass losses measured at the remaining T ranges, were consistent in the ground samples, thus the grinding for 2 min caused the homogenization of the crystal structure of vermiculite [ΔM(150-500°C)=7.6±0.7%]. DTA curves after grinding and cation exchange indicate an important exothermal peak at 795-870°C, its temperature depending on exchangeable cation. It indicates the formation of high temperature phases (enstatite, forsterite, spinel). The lowest temperature of the peak (795°C) was observed in V-gr-Li, here lithium silicate was formed. The highest peak temperature (870°C) was found in V-gr-K, where almost only forsterite developed. These exothermal peaks were very weak in unground V with various exchangeable cations.

Application of vermiculite and limestone to desulphurization and to the removal of dust during briquette combustion

Abstract: Small domestic cooking furnaces are widely used in China. These cooking furnaces release SO 2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO 3 , and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO 3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO 3 and SO 2 and to convey O 2 into the interior of briquette; CaCO 3 is used as a chemical reactant to react with SO 2 to form CaSO 4 ; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO 4 , a product of SO 2 reacting with CaCO 3 and O 2 . The formation of CaSO 4 effectively reduces or eliminates SO 2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO 3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO 3 , and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.

Ammonia release on heating of mechanically treated vermiculite saturated subsequently with ammonium

Abstract: The differences in thermal behaviour of vermiculite before and after mechanical treatment (sonication and grinding), saturated subsequently with ammonium, were studied by TG, DTA, EGA and IR techniques. Sonication produces only a small modification in the NH4+vermiculite decomposition attributed to a small particle size. Grinding causes an important but different change in the thermal behaviour of NH4-vermiculite. The temperature of ammonium loss is lowered stepwise showing that grinding modifies the bonding energy between and the surface of vermiculite.

Phytotoxicity and fate of 1,1,2-trichloroethylene: a laboratory study.

Abstract: 1,1,2-Trichloroethylene (TCE), a chlorinated organic contaminant, poses serious environmental concerns. A study was conducted to evaluate the phytotoxicity of TCE to a crop species and its fate in vermiculite. Growth bioassays were carried out using carrot (Daucus carota L.) as the test species. Three different concentrations, 0.25, 0.50, and 1 ppm were used to evaluate phytotoxicity of TCE. When added to petri plates with cotton pads, TCE did not have any effect on carrot seedling growth. However, when added to vermiculite, it significantly suppressed growth. Shoot growth was inhibited only at the 1 ppm concentration. Recovery experiments were carried out to study the fate of TCE in vermiculite. A significant decline in the percent recovery was observed with time. Interestingly, TCE additional peaks (unknown organic molecules) were detected with declining concentrations. The available chloride ion concentration in vermiculite containing 1 ppm of TCE for 24 hr was significantly higher compared to control.

Vermiculite heat-insulating fabric

Abstract: The present invention relates to a vermiculite heat-insulating fabric It is formed from vermiculite and fibre, in which the described fibre includes melamine resin fibre, glass fibre and plant fibre, and the described vermiculite is its powder obtaining by making vermiculite undergo the processes of calcination, expansion, pulverization and grinding, and the ratio of the vermiculite and fibre is2:8 to 8:2 In the described fibre the melamine resin fibre content is 10%-20% of total weight of the fibre, and the rest is glass fibre and plant fibre The production process includes the followingsteps: preparing vermiculite powder according to the above-mentioned steps, mixing said powder into the fibre, utilizing non-woven fabric production technique to make the fibre material into the invented product

A composite for grow in plant

Abstract: PURPOSE: A natural soil improver comprising foamed perlite, foamed vermiculite and kaolin is provided to remove bad smell, to purify polluted water, to neutralize acidified soil and help the growth of plants. CONSTITUTION: The soil improver having high adsorption is composed of 35-45wt.% of foamed perlite for promotion of plant growth, 50-60wt.% of vermiculite with adsorbing property to remove bad smells, and 5-15wt.% of kaolin, wherein the foamed perlite and vermiculite are obtained by heating the minerals(0.1-0.8mm) to 700-1300deg.C rapidly.