Showing papers on "Vermiculite published in 1982"

Interpretation of pH and Eh trends in a fluvial‐sand aquifer system

Abstract: Ground waters and aquifer materials from a shallow fluvial-sand aquifer system (1-km-long flow path) were sampled and analyzed to determine the hydrogeochemical processes affecting pH and Eh (measured Pt electrode potential). The aquifer system is a fine-grained sand (K ∼ 10−3 cm/s) composed principally of quartz and plagioclase (70% of all grains) with minor biotite (partially altered to vermicuiite) and trace amounts of calcite. Acid neutralization capacity measurements and X ray diffractograms suggest that acid precipitation recharging the aquifer undergoes a two-step neutralization process; the first step involves reactions with the surfaces of mineral grains, mainly with plagioclase and biotite, and the second step involves an irreversible neutralization involving biotite alteration to vermiculite and carbonate mineral dissolution. During migration through deep confined parts of the aquifer ground waters attain equilibrium with calcite. A thermodynamically based redox model of a closed-oxidant system satisfactorily accounts for the sequential reduction of dissolved oxygen, ferric oxides, and sulfate in the aquifer by the oxidation of dissolved organic carbon and (for oxygen only) ferrous iron. Because of the problems of using Pt electrodes in ground waters it is recommended that Eh measurements be supplemented with dissolved oxygen and sulfide measurements.

Apparatus for the expansion of mineral matter, especially perlite and vermiculite

Abstract: Perlite and vermiculite are blown by injecting the particles, entrained in a carrier gas, through a burner at the bottom of a fluidized bed furnace, into the latter with, within and codirectionally with the flame to ensure uniformity of the product.

Weathering processes and pickeringite formation in a sulfidic schist: a consideration in acid precipitation neutralization studies

Abstract: Extremely low abrasion pH values (2.8–3.3) characterize the weathering products of the Partridge Formation, a Middle-Ordovician metamorphosed, black, sulfidic shale. The local occurrence is observed of two sulfates that are rare in the Northeast: pickeringite and jarosite. X-ray diffraction studies of the weathering residues and the sulfate efflorescences have also identified dioctahedral and trioctahedral illite, kaolinite, vermiculite, and an 11–12 A phase, thought to be a type of randomly-interstratified biotite-vermiculite. From the mineralogical studies, qualitative weathering processes for the schist are formulated. A probable mechanism for the intense chemical weathering of the schist appears to be oxidation of iron sulfides to form iron oxide-hydroxides, sulfates, and sulfuric acid. This natural weathering process is proposed as an analog to anthropogenic low pH rock weathering resulting from acid precipitation. In the Northeast,natural weathering rates, may, in places, significantly affect the water chemistry and mineralogy used to quantify total (natural plus anthropogenic) weathering and leaching rates.

Urease Clay Interactions: I-Adsorption of Urease on Clays Saturated with Different Cations

Abstract: Adsorption of urease on kaolinite, bentonite and vermiculite saturated with sodium, calcium and aluminium was studied. Relationship between clay concentration and the enzyme adsorption was linear up to a clay concentration of 40 mg/ml. Kaolinite adsorbed least amounts of urease followed by vermiculite and bentonite, which had almost same adsorption. Aluminium clays adsorbed maximum amounts of enzyme whereas calcium and sodium clays behaved almost similarly. The maximum adsorption of urease occurred at pH 6.5 for kaolinite and bentonite and at pH 7.5 for vermiculite clays.

Production of articles from minerals

Abstract: Vermiculite ore is contacted with an aqueous solution with at least one salt of sodium, lithium or an organosubstituted ammonium cation followed by aqueous washing so that the ore swells. The swollen vermiculite in aqueous suspension is subjected to a shearing action until a suspension containing vermiculite particles having dimensions less than 50 microns is produced with elimination from the suspension of all particles having a diameter larger than 50 microns. Water can then be removed from the suspension.

X-ray Studies on the Distribution and Characterization of Layer Silicates in Some Alluvial Soils

Abstract: The clay-mineral composition of soil from four profiles representing the Hissar, Suniarheri, Tohana and Bhanra soil series developed on alluvium has been examined using the x-ray diffraction and microscopic techniques Quartz and feldspars were the dominant minerals present in the sand fractions; muscovite, biotite and chlorite in association with other accessory minerals were also indicated. Semiquantitative estimates of minerals in the silt fractions suggested the dominance of illite followed by mixed-layer minerals, chlorite, and vermiculite. A similar distribution pattern was also observed in the clay fraction which contained, in addition, smectite and chloritized-smectite. The illite present in the soils was found to consist of both the dioctahedral and trioctahedral varieties, and the latter appears to have undergone transformation to smectite-like minerals through intermediate stages of (10–14 A) inters-tratification.

Electrolytic cell vermiculite diaphragms

Abstract: Diaphragms for use in electrolytic cells, e.g., chlor-alkali cells, are beneficially prepared using pulverized expanded vermiculite in place of the historically popular asbestos.

Potassium and Magnesium Recovery from Selected Soils of the Allegheny Plateau

Abstract: Many soils of marginal land areas in the northeastern United States have been depleted in K and Mg by either poor soil fertility management or erosion. These soils also contain clay minerals such as mica and vermiculite that are prone to fix K and Mg. The combination of depleted levels of K and Mg and clay minerals may have an adverse effect on the recovery of K and Mg applied to these soils. The objective of this study was to determine the effect of clay minerals on the recovery of K and Mg applied to A and B horizons of seven Appalachian soils. The recovery of K and Mg applied to the A and B horizons of seven soil series common to the Allegheny Plateau region of western Pennsylvania and northern West Virginia was determined using 1N ammonium acetate, double acid (0.05N HCl in 0.025N H₂SO₄), and oat seedlings. Potassium recovery by all methods ranged from approximately 60% of applied K in soils containing small amounts of mica and/or vermiculite to approximately 15% in soils containing moderate amounts of these clays. Almost all of the applied Mg was recovered by the soil testing methods, while the oat seedlings were only able to recover about 4% of the applied Mg. Recovery of Mg was not directly affected by clay type. The ammonium acetate method was able to predict the recovery of K by the oat seedlings better than the double-acid method. Magnesium recovery by the oat seedlings was predicted equally well by both soil testing procedures.

Clay Mineralogical Studies in Relation to Soil Development And Vegetation in Haldwani Forest Division of Uttar Pradesh

Abstract: Presence of kaolinite in significant amounts, hydrated axides of Iron, comparatively high organic carbon in lower layers, absence of 14 7 and 4.7° A peaks of chlorite and vermiculite and degraded nature of illite in the soils of Naghan and Gunio Rao compartments, qualifies them to represent compuatively more weathered soil sequences. Syzygium cumini indicating relatively moist regime and hence probably more intense weathering have been found to be natural associate of Shoreo robusta in comparatively more weathered soils. Significant amount of blite with smal; quantities of chlorite and vermiculite in the clay fraction of Guliapani and Sunmanthapia compartments having mainly Shorea robusta in the upper storey with non-exacting species like Mallotus philipensis in the second storey, shrub and ground , layer, suggest that soils of these sites are comparatively less weathered representing young sequences and more fertile sites.

Clay mineralogical and ammonium fixation characteristics of some tropical upland rice soils

Abstract: In view of the agronomic and economic significance of NH4 fixation in soils, an attempt has been made to relate this to the most reactive mineral constituents of soils ‐ the clay minerals, under the temperature‐moisture regimes normal to tropical upland rice soils. Laboratory fixation study was done with NH4, concentrations similar to those common in soils upon N fertilization, and under alternate wetting and drying at ambient temperatures rather than at 100°C as in many published studies. Results of the investigation show that soil clays with dominant vermiculite and montmorillonite fix the greatest proportion of applied NH4 (94 and 91%), followed by beidellite (72%) and x‐ray amorphous (45–64%) clays. Fixation is negligible (10%) in the clay with mineral suite consisting of hydrous mica, halloysite, and chlorite. Crystallinity of minerals seems to influence NH4 fixation appreciably.

Preparation of alcohol by fermentation

Abstract: PURPOSE:To improve the rate of production of alcohol, remarkably, by using pulverized porous vermiculite as the substrate for supporting bacterial cells in a fermentor. CONSTITUTION:Pulverized porous vermiculite prepared, e.g. by thermal dehydration of biotite, is charged in a fermentor together with an alcohol-producing bacterial strain. The medium components, a defoaming agent, etc. are additionally charged into the fermentor, and the alcohol-production is carried out.

Vermiculite as a deposit modifier in boilers

Abstract: Vermiculite is injected into a carbonaceous fuel-fired furnace, at 3000-1200 DEG F, to facilitate removal of fly ash deposits by steam or air blowers.

X-ray Microprobe Technique in the Studies of Clay Minerals: Vermiculite

Abstract: Factors intervening in evaluating various microstructural characteristics of clay minerals by X-ray microprobe technique, are elucidated. Three vermiculite minerals of different origin have been studied by both wave-length and energy-dispersive X-ray microprobes following the novel pretreatment and analytical procedures. X-ray images, presented here for vermiculites, heat treated at lower temperatures, indicate homogeneity in elemental distribution. On the other hand, samples which are treated at higher temperatures, show heterogeneity in elemental distribution. Variations in elemental distribution with rise in temperature have been explained in terms of the changes occurring in the structure of the mineral. It is shown here that X-ray microprobe technique is very effective in determination of trace elements in clay mineral.