Showing papers in "Applied Clay Science in 1990"

TL;DR: In this article, the authors studied the firing transformations undergone by mixtures of illitic-kaolinitic clays containing CaCO 3, free quarts, iron oxides and other impurities.

TL;DR: In this article, fine fractions of bentonites from Jelsový Potok (JP), Blsany (BL) (Czechoslovakia), and Mittelherwigsdorf (MI) (German Democratic Republic) were repeatedly treated with HCl and Na2CO3 solutions.

TL;DR: In this paper, a mercury intrusion porosimeter has been employed to develop cumulative and differential pore-size distributions for five samples each of four clay soils, and two consecutive intrusions were performed on each of the specimens thus allowing differentiation of free and entrapped porosity.

TL;DR: In this paper, common soil and rock forming minerals were tested in the presence of lime as slurries and pastes in order to assess their reactivity and the nature of the reaction products.

TL;DR: The structural and textural evolution under thermal treatment of two Spanish palygorskites, one magnesium-rich and the other aluminium-rich, was studied using IR and X-ray techniques, and the structural modification that the samples undergo on heating, is shown as discussed by the authors.

TL;DR: The Creataceous Clay Spur bentonite exhibits unique physiochemical properties which make it suitable for a variety of industrial applications as mentioned in this paper, which can be attributed, in part, to variations in the structural chemistry and consequently the surface chemistry, of the smectite.

TL;DR: In this article, the deflocating ability of some phosphates, with different P2O5/Na2O molar ratios, towards very concentrated aqueous suspensions (62.5 wt.%) of three clays (named Castellamonte, Samone and Debbia), widely used in the factories of Sassuolo (Italy), has been investigated by means of rheological measurements in the absence and the presence of calcium (II) ions (0−6·10−3 mol dm−3).

TL;DR: Clay research is focused on four major fields: (a) soils and agriculture; (b) industrial applications; (c) engineering and geotechnics; (d) research and development of new products.

TL;DR: In this article, the effect of oxide minerals on the undisturbed and remoulded strength of marine clays is investigated. But the results of these experiments are limited, as they are limited to the case where the oxide minerals are concentrated at points of contact between silicate minerals.

TL;DR: In this paper, the pH of water standing in pools in deposits of kaolin-family clays tends to be low, i.e. pH 4 to 5, whereas streams flowing over primary, and clay-parent, silicate rocks typically yield a pH of 7 or higher.

TL;DR: In this article, a microfabric classification of argillaceous rocks and nonlithified clay sediments and soils is proposed based upon fabric determined from scanning electron micrographs and by using a signal intensity gradient technique.

TL;DR: In this article, it was demonstrated that poorly crystalline inorganic matter present in Athabasca oil sands is comprised of aluminosilicates, most probably allophane-like minerals.

TL;DR: Loto et al. as discussed by the authors used Igbokoda pure silica sand as a base sand for the development of an efficient synthetic moulding sand. But the results showed that the added Na2C03 gave improved properties to the molding sand though with a tendency towards impaired collapsibility and toughness.

TL;DR: In this paper, the theory of colloid stability was used to reveal a new possibility of interaction between montmorillonite and humic substances, and the calculations indicated that heterocoagulation of these species can take place in the presence of salts and is also dependent upon pH.

TL;DR: In this paper, the effect of the pH and NaCl on the interaction energy of the humic acid and the fulvic acid on H-montmorillonite was investigated.

TL;DR: In this paper, an investigation was made into the effects of cassava flour and coal dust additions on the mechanical properties of a newly developed synthetic moulding sand made from Igbokoda clay and silica sand.

TL;DR: In this paper, the effects of mixing varying amounts of clay, tempering water and sand on moulding properties were investigated. And the green and dry strength and shatter index of the mixtures were determined.

TL;DR: In this paper, a method of enrichment by means of liquid separation was applied to obtain material of high quality, based on the mineral and chemical composition and texture of these kaolins, and no substantial differentiation was apparent in the distribution of the minerals with grain size.

TL;DR: In this paper, the decylammonium cations intercalated in the interlamellar space of vermiculite are decomposed under laboratory conditions, leading to NH 4 + -vermiculites after, at least, one year storage.

TL;DR: In this article, the flocculation behavior of kaolinitic clay suspension using oxidized cassava starch (hypochlorite and peroxide oxidized, charged and uncharged) was investigated.

TL;DR: In this paper, the properties of homogeneous kaolin, geostatically consolidated in the laboratory, were described based on rigid analytical and experimental boundary conditions, and differences in compaction behavior were documented by differences in the compression and swelling parameters and the dissipated deformation energy.

TL;DR: In this paper, the carbon content of HFC before heating was 14 wt%, changing to 18 wt% at 873 K and to 8 wt % at 1673 K.

TL;DR: In this article, the specific lateral and basal surface areas of the kaolinite were calculated from both the specific surface area by the BET method and the particle size distribution curves, and the number of rheological parameters was reduced to three because of the application of empirical relations among them.

TL;DR: In this paper, the chemical composition of hot-mineral spring waters with temperatures near 60°C and the altered rock petrography was studied. But the results of the study were limited to three types of clay minerals: irregular talc-saponite mixed-layer minerals of stevensite type, highly enriched in Br, S and Ga from the peat near the spring; smectites of montmorillonite-beidellite type enriched in magnesium in peat developed near a spring; and halloysites formed from amorphous products resulting

TL;DR: The efficiency of Na-montmorillonite in removing oxidation products from lubricating oils was found to be inversely proportional to the amount of water adsorbed in the clay as mentioned in this paper.

TL;DR: In this article, a recently explored and already exploited 10 Mt bentonite deposit is described in terms of mineralogy and geology, and additional testing has been carried out in order to establish optimum utilization for drilling mud, foundry sands, and bleaching earth for vegetable oils.