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Showing 1 to 20 of 24 for “"gibbsite"”.
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An Improved MUSIC Model for Gibbsite
… studies that have proposed MUSIC models for gibbsite surfaces have purported to achieve a very good fit with potentiometric titration data. However, in order to achieve such results, several significant parameters, such as the number of surface sites, site densities, and pKa values were …
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Antisolvent gibbsite crystallisation from synthetic Bayer liquor
The current Bayer precipitation of gibbsite is notoriously slow and is considered to be the rate limiting step of the Bayer process. The present industrial reactor configuration involves precipitating gibbsite inside a series of large stainless steel agitated vessels due to the slow precipitation …
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Characterization of Residual Mineral Content of Bauxite Stockpiles in Saline County, Arkansas: An XRD Analysis Approach
… with preliminary X-ray fluorescence (XRF) data. Gibbsite and kaolinite dominate the mineralogy, with gibbsite showing strong positive correlations with zirconium (r = 0.76) and niobium (r = 0.72). Siderite, a minor mineral phase, appears associated with niobium, zirconium, and titanium, …
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Clay mineralogy and soil classification of alluvial and upland soils associated with Blackwater and Nottoway rivers in southeastern Virginia
… clay minerals; that montmorillonite, mica, gibbsite quartz, and vermiculite were of lesser quantities; that chlorite, feldspar and interstratified minerals were of trace amounts. Kaolinite represents about 21-70%, HlV 11-60%, montmorillonite 0-20%, mica 0-16%, gibbsite 0-13%, quartz 1-12%, …
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Boron chemistry in selected Virginia soils and hydroxy aluminum and iron systems
… unavailable forms. Boron adsorption on both gibbsite and goethite was pH and temperature dependent. At pH 6.5, boric acid was major species in the system and B was absorbed by the negatively charged surface of gibbsite and the positively charged surface of goethite. At pH 10, borate was …
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The geochemistry and phosphorus sorption characteristics of Mgeni catchment sediments
… material (< 2mm) which is composed of kaolinite, gibbsite, goethite, mica and other undifferentiated· 2: 1 layer silicates and quartz. Kaolinite, gibbsite and goethite are found extensively throughout the catchment area and are the result of intense weathering. These minerals readily sorb cations …
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Pedogenesis, weathering processes, and elemental distribution along a soil climosequence in the southern Piedmont
… indices developed for each site. Kaolinite and gibbsite are poor indicators of soil age, weathering intensity, or paleoenvironment because of complex mechanisms of formation. Kaolinite genesis is shown to result from i) desilication of 2: 1 phyllosilicates in surficial horizons ii) hydrolysis of …
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Effect of aluminum oxyhydroxide coatings on the performance of limestone drains
… indicated that amorphous poorly crystalline gibbsite is the primary Al coating but scanning electron microscope analysis also suggests the possible presence of a poorly crystalline sulfur containing phase, such as hydrobasaluminite. The experimental data were used to calculate the diffusion …
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ΣΥΜΒΟΛΗ ΣΤΗ ΒΕΛΤΙΣΤΟΠΟΙΗΣΗ ΤΗΣ ΕΚΧΥΛΙΣΗΣ ΤΟΥ ΔΙΑΣΠΟΡΙΚΟΥ ΒΩΞΙΤΗ
… IN BAUXITES OCCURS IN THREE DISTINCT MINERALS: GIBBSITE, BOEMITE, AND DIASPORE. THE LEACHING CONDITIONS DEPEND ON THE MINERALOGY OF THE BAUXITES. THE DIASPORIC BAUXITES NEED STRONGER LEACHING CONDITIONS THAN THE OTHER TYPES OF BAUXITES. THE AIM OF THIS WORK WAS TO STUDY THE MAIN VARIABLES WHICH …
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The genesis and characteristics of the fragipan of the Beltsville soils
… quartz and illite content, and the presence of gibbsite in the horizons below the fragipan indicate that this material has undergone more intensive or a different type of weathering than the material in the solum. Two horizons high in clay were found in each of the profiles studied: one above …
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Soil mineralogy of an upper coastal plain landscape in Virginia
… soils were dominated by kaolinite, HIV, and gibbsite. Wet soils were less mature in mineralogy due to the lack of weathering activity. All but the Piedmont soils contained a surface mica enrichment, believed to be eolian additions. Well-drained and moderately well-drained soils had a more …
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Soils and morphology of Carolina bays, Eastern Shore, Virginia
… scarp were less weathered as evidenced by less gibbsite and greater amounts of weatherable minerals in subsurface horizons. All soils examined had sandy subsurface horizons indicating a sandy environment of bay formation. Size distribution of sandy fractions revealed that differential sorting …
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Active neutralisation and amelioration of acid mine drainage with fly ash
… was attributed to the precipitation of primarily gibbsite and various other mineral phases at pH values >5.5. As the pH increases, sulphate is adsorbed via Fe(OH)3 and gypsum precipitation at elevated pH. Sulphate attenuation with fly ash was excellent, achieving 98 % attenuation with beaker scale …
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Molecular Structure, Diffusion Dynamics and Hydration Energetics of Non-Confined Water and Water at Mineral Surfaces
… and energetics. Results for brucite [Mg(OH)2], gibbsite [Al(OH)3], and hydrotalcite [Mg2Al(OH)6Cl·2H2O] will illustrate these effects for hydroxide phases, and results for talc [Mg3Si 4O10(OH)2] and muscovite [KAl2(Si 3Al)O10(OH)2] those for silicates. Topics highlighted include the …
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Catalytic Decomposition of a Perfluorinated Carbon Proxy Using Alumina-based Catalysts
… derived from an industrial, commercial Bayer-gibbsite (ABG) was found to decompose PFC’s at a high % conversion. Above a threshold temperature of 500 ℃, an increase in reaction temperature produced higher catalyst performance (up to 700 ℃). Alumina derived from laboratory-grade gibbsites, …
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Phosphorus Losses in Runoff from Virginia Soils
… such as hydroxy-interlayered vermiculite (HIV), gibbsite, and amorphous Al. Samples dominated by kaolinite retained very little P. Application of these results to runoff data showed that soil types with a HIV:kaolinite ratio > 0.5 caused significantly less DRP in runoff for a given soil WSP level …
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Pedogenesis and geomorphic implications of soils developed on Blue Ridge alluvial fans, Virginia
… whereas, kaolinite is abundant in unit B. Gibbsite is higher in unit B than unit A. Weathered ρ<sub>r</sub><sub>b</sub> is not different among five sites on a bajada within the central part of the study area, but it is different from five other Sites on either end of the study area. Free Fe …
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Innovative, Platy Nano-Additives as Efficient Flame Retardants for Polymer Nanocomposites
… selective surface modification of µ-hydroxy (gibbsite-like) surfaces. The surface modification was achieved by siderophilic ligands such as catechol derivatives. The catechol functional group (1,2-dihydroxyphenyl) forms stable chelate-complexes with the aluminum cation of the octahedral …
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