Showing papers in "Applied Clay Science in 1987"

TL;DR: In this paper, the use of pillared, cation-exchanged and acid-treated montmorillonites as catalysts for reactions which can be carried out on a preparative laboratory or industrial scale is discussed.

TL;DR: In this paper, four clayey soils displaying the range of properties of the marine clays from eastern Canada were selected for this study and treated with different amounts of quick, hydrated and agricultural lime, at different water contents.

TL;DR: There is a close relationship between the occurrence of high-temperature crystalline phases and the colour of clay bricks after being fired under oxidizing conditions at 1000°C as mentioned in this paper.

TL;DR: In this paper, it was shown that cyclic tests lead to a gradual destruction of the durable contacts in the clay structure and their transformation into less durable ones, and a reconstruction of the structure of the clays takes place, manifested by the destruction of large microaggregates and by disorientation of structural elements.

TL;DR: In this article, the authors examined the Bingham yield stress for the suspensions of the amorphous iron hydroxide and its association with the kaolinite surfaces by means of electron microscopy and zeta potential and surface area determinations.

TL;DR: In this article, the interaction of Cs+ with a montmorillonitic and an illitic clay suspended in solutions of synthetic groundwaters, sodium perchlorate, or sodium acetate was examined over the range of initial cs+ concentrations of 10−8 to 10−5 mol/l and at 25° and 80°C.

TL;DR: In this paper, the effect of impact and friction milling on the structure and texture of a bentonite, in its natural and in several monoionic forms (H +, Na +, Ca 2+, Al 3+ ), is studied.

TL;DR: The ability to disperse different clay materials in aqueous suspensions into fundamental particles 1-10 nm thick and combine them in various combinations and proportions has stimulated research into the more effective use of the unique properties of these materials as discussed by the authors.

TL;DR: In this article, bitumen-free solids from different grades of Athabasca oil sand were fractionated according to particle size before and after treatment with sodium pyrophosphate (Na4P2O7) solution.

TL;DR: In this article, the authors demonstrate that framework, 2:1 sheet, and fibrous sheet silicates (zeolite, vermiculite and palygorskite) when added to apatite-H2O systems, work in this way.

TL;DR: In this article, multiple regression analyses of the data clearly show the amorphous Fe and Alorganic C-clay interaction in stabilizing the size separates, and the β coefficients obtained from the regression analyses have given an insight into the relative importance of the organic matter and clays in the stabilization of the mechanical separates.

TL;DR: In this paper, major and trace-element mobilities have been investigated in hydrothermally altered zones of Miocene volcanic rocks on the island Lesbos and three types of alteration have been recognized.

TL;DR: In this article, a 3 MV electron microscope was used for the study, which comprised filling of Na-smectite in powder form in a closed cell that was penetrated by electron radiation in the microscope after exposing the clay to water and thereafter drying it.

TL;DR: In this article, the authors demonstrate the successful application of high-resolution electron microscopy to the determination of mineral transformations, and show that the initial short needles of palygorskite show predominantly 4.0-4.2-A layers which evolve into fibres and lath-shaped crystals.

TL;DR: In this article, the fluorine content of clays from Lower Saxony and Bavaria was determined before and after firing, and a clear relationship between fluorine emission during firing and the Ca-content of the raw materials was demonstrated.

TL;DR: In this paper, a multivariate statistical analysis of a total of 29 macro, trace and rare earth elements by instrumental neutron activation analysis (INAA) on 129 pottery specimens from southwestern Cyprus obtained from 38 archaeological sites, ranging in age from the Neolithic through to Roman, has indicated that the large majority of the ceramics had been manufactured locally.

TL;DR: In this article, the migration behavior of Sr-90 and Cs-137 in freshwater and marine clays from the Austrian Molasse was studied by percolating chloride solutions through small columns which contained undisturbed clay samples.

TL;DR: In this article, the cation exchange characteristics and mineralogy of six soils collected from southeast Nigeria have been investigated, and it is suggested that the aggregates in the 20-200 μm fractions of the Uturu/Akaeze Group soils could represent undisaggregated rock fragments inherited from parent material.

TL;DR: In this paper, coal-mining carboniferous clay-, silt and sandstones of the Ruhr area (N.W. Germany) are brought to the surface where they are dumped and become subject to weathering.

TL;DR: In this article, the role of the clay in the hydrogen photoproduction process is discussed, and the maximum of hydrogen production obtained for a particular ratio [MV 2+ ]/[Clay] and for the fact that pre-exchanged MV 2+ -Clay is unable to assist in the HPC process.

TL;DR: A nearly pure bentonite, revealed by drilling at S'Aliderru in northwestern Sardinia, Italy, has been opened up and the mine is among the largest in Europe as mentioned in this paper.

TL;DR: The 9 GHz EPR spectra of Mn 2+ impurity ions incorporated into the tactoid structure of hydrated Ca-montmorillonite has been investigated in the temperature interval 300-500 K as discussed by the authors.

TL;DR: In the clay fraction of the Villamayor Sandstone (Salamanca, Spain) as mentioned in this paper, pore sizes are in the mesoporosity range (2-40 nm) and micropores are absent, and specific surface area values range from 62 to 78 m2 g−1.

TL;DR: In this article, the adsorption and mechanism of interaction of vermiculite with the organophosphorus pesticides dichlorvos, phosdrin, sumithion and dimethoate were studied.

TL;DR: The influence of sugar and glycerol on the laboratory transformation of synthetic lepidocrocite and on the synthesis of Fe(III) oxide phases by Fe 2+ oxidation in solution was studied by powder X-ray diffraction, transmission electron microscopy and by measuring hydrolysis rates.

TL;DR: In this paper, the adsorption and catalytic decomposition mechanisms of thioacetamide, thiobenzamide and 2,6-dichlorothiamid on Al- and Ca-montmorillonite (Upton, Wyoming) have been studied.

TL;DR: In this paper, the results indicated that the satisfactory material could be distinguished from the less satisfactory by ammonium chloride and exchangeable-K, oxalate-Fe, (Feo) colour on firing to 600°C and 800°C, and by the content of sand and very coarse silt.