bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical Properties of Organic Complexes of Montmorillonite
Authors: Greene-Kelly R. 
Published: December 2006

AbstractThe optical properties of oriented montmorillonite aggregates were measured in both non-complexing and complexing media. The changes observed lead to the following conclusions. Preparing oriented aggregates of clays for optical examination requires considerable care to avoid spurious orientation effects. In determining the optical constants of montmorillonite aggregates the medium must wet and enter the aggregate readily and displace the air, particularly from the smaller pores, otherwise large form birefringence effects of uncertain magnitude will occur. A suitable medium is likely to be one that complexes montmorillonite. The complex it forms must have relatively isotropic interlamellar layers and this is more likely with isodimensional molecules. Consideration of complexes with simple compounds suggests that the intrinsic birefringence of aggregates is overestimated by conventional techniques.Forming complexes with aromatic compounds usually results in the birefringence of the aggregate being essentially determined by the orientation and anisotropy of the intercalated molecules.
The Interaction of Kaolinite with Polyphosphate and Polyacrylate in Aqueous Solutions—Some Preliminary Results
Authors: Bidwell J. I. , Jepson W. B. , Toms G. L. 
Published: December 2006

AbstractThe choice of kaolinite sample for surface chemical studies is examined. An adsorption apparatus, particularly suited for those studies where the adsorbate acts as a deflocculant, is described. Some preliminary results are given for the adsorption of total phosphate from tetrasodium pyrophosphate solutions and of polyacrylate from sodium polyacrylate solutions. The release of aluminium and silicon from the kaolinite was measured; with tetrasodium pyrophosphate, aluminium-phosphate complexes are formed.Competitive adsorption measurements suggest that the polyacrylate is adsorbed on the positively charged edges of the kaolinite.
Dickite from Job's Hill St Mary, Jamaica
Authors: Davis C. E. , Thompson B. E. , Taylor W. A. , Holdridge D. A. 
Published: December 2006

AbstractExamination of rock samples from Job's Hill, St Mary, Jamaica, by chemical, X-ray, differential thermal, and infrared analyses showed predominant dickite with associated nacrite and kaolinite. The uniqueness of this deposit makes it possible that selected material could be used as a standard mineral.
The Differential Thermal Analysis of Flocculated Clay Samples
Authors: Dollimore D. , Heal G. R. , Horridge T. A. 
Published: December 2006

AbstractClays may be flocculated from suspension by various polymeric flocculating agents. In this study the technique of differential thermal analysis is used to identify the flocculating agent and to study its behaviour when adsorbed on the clay particles. It is shown that the clay particles display normal properties on sedimenting in the presence of sufficient polymer to cause flocculation. The differential thermal analysis trace for clays is only affected when the flocculating agent is present on the surface in quantities in excess of that required for effective sedimentation.
On the characterization of ceramic clays
Authors: Cole W. F. , Lancucki C. J. , Powell D. A. 
Published: December 2006

AbstractCeramic clays are characterized by a method that stems from the IL/MA procedure proposed by Keeling (1958a, b) but which is more rapid to perform and more basic in concept. By thermogravimetric methods an estimate is made of both OH water and interlayer plus physically adsorbed water. These are plotted against each other in a manner similar to the IL/MA plot. The composition of the clay can be characterized uniquely on such a diagram by estimating either the quartz or the free silica contents of a sample, its silt, and < 2μ fraction, and plotting for each on a 100% clay basis their OH water, and interlayer and physically adsorbed water. Simple methods are given for assessing these factors. The determination of interlayer water content could form the basis of a method of plant control of clay composition in a way similar to that proposed by Keeling using moisture adsorption determinations.
Bentonitic beidellite-mudstone from the Faeroe Islands
Authors: Sabine P. A. 
Published: December 2006

AbstractA Tertiary mudstone from beneath worked coal among the basalts of the Faeroe Islands is mainly composed of aluminium-rich dioctahedral smectite, disordered kaolinite (amounting to about one quarter of the smectite) and probably about 13 ~ amorphous material. The texture is the result of crystallization in place. Chemical analysis suggests an ionic formula for the smectite of (Ca0.32Na0.10K0.04) (A13.88 Fe0.06+3Fe0.05+2Mg0.29) (Si6.71 A11.29) O20 (OH)4· 3·0 H20, which corresponds closely to beidellite. The total charge on the interlayer cations is 0·78 and cationexchange capacity is 52·5 meq/100g. DTA curves yielded endothermic peaks at 140°C, 220°C, and 555°C with an exothermic peak at 955°C. The nomenclature is discussed and the material considered to be a bentonitic beidellite-mudstone; the rock, which has crystallized in place has similarities with tonstein in its mode of formation.
Two mixed-layer mica-montmorillonite minerals from sedimentary rocks
Authors: Gilkes R. J. , Hodson F. 
Published: December 2006

AbstractTwo clay deposits, the Stafford Clay marker bed from the Middle Coal Measures of North Staffordshire and the Woolhope Bentonite from the Silurian, Woolhope Limestone near Woolhope in Herefordshire are described. These clays contain mixed-layer clay minerals which have been separated by sedimentation for mineralogical and chemical analysis. Both minerals are shown to be mica-montmorillonites with MacEwan stacking parameters PA= 0·59, PAA= 0·44 and PA= 0·56, PAA= 0·70 respectively. In both cases the average layer charge (1·22 and 1·46) is intermediate between that of montmorillonites and micas but the exchangeable cation layer charge (1·07 and 1·27/montmorillonite layer) and fixed cation layer charge (1·32 and 1·63/mica layer) of the component layers are higher and lower respectively than the normal range of montmorillonites and micas. Some chemical data are given for the raw material which yielded these minerals and for associated and related rocks. In particular K, U and Th determinations permit a discussion of the natural gamma-ray flux which is sufficiently more intense than that of the associ~.ted sediments to permit its detection by scintillation counter in the field.
Primary aliphatic alcohol-homoionic montmorillonite interactions
Authors: German W. L. , Harding D. A. 
Published: December 2006

AbstractComplexes formed by straight chain, primary, aliphatic alcohols from methanol to n-decanol with Ca- and Na-montmorillonite from the liquid and vapour phases, have been investigated by X-ray techniques. Satisfactory complexes are formed more readily by the Ca-mineral and from the liquid phase rather than from the vapour phase. Molecular configurations of the adsorbed molecules are suggested consistent with the experimental data. The importance of cation-dipole interactions for the lower members of the series is stressed.
Mineralogical studies of a species of stevensite from the Obori mine, Yamagata Prefecture, Japan
Authors: Shimoda Susumu 
Published: December 2006

AbstractA variety of stevensite was collected at the Obori mine, Yamagata Prefecture, Japan. Analysis shows close agreement with published data for stevensite. Chemical composition: SiO2 52·76%; A1203 trace; Fe203 0·38%; MgO 23·67%; MnO 1·57%; CaO 2·19%; Na2O 0·37%; K2O 0·00%; H2O+ 6·52%; H2O− 12·38%; Total 99·84%. The structural formula is (Fe0·04 Mg5·31 Mn0·02) Si80·1 020·00 (OH)4·00·Ca0·36, Na0·10.This specimen shows an interstratified structure of dehydrated and hydrated layers, the former caused by dehydration of the interlayer water, although stevensite essentially contains a non-swelling layer and shows interstratification. The intensities and spacings of the 00l reflections change successively with changes in humidity. When treated with water and glycerol, the 00l reflections are similar to those of montmorillonite. The DTA and TG curves are similar to those of stevensite and an interstratified mineral of talc and saponite.
Gélification de vermiculite dans des solutions d'acideγ-aminobutyrique
Authors: Rausell-Colom J. A. , Salvador P. S. 
Published: December 2006

AbstractVermiculite single crystals swell to the gel state as a consequence of treatment with concentrated solutions ofγ-aminobutyric acid.The amount of swelling was determined, by measuring by X-ray diffraction the separation of the elementary silicate layers in the gel-like crystals.By application of pressures into the gels along the swelling direction, a direct measure of the swelling pressure is obtained. The relation between swelling pressures and equilibrium interlayer distances is a function of both cationic concentration and dielectric constant of the solution. Measured swelling pressures are consistent with a model based on formation and interaction of diffusedouble layersof aminoacid cations around the silicate particles, these having a Stern layer of an approximate thickness of 5 Å. The specific chemical adsorption potential of the system has been estimated asφ= 3·3 + 0·2 Kcal/mol.
The neoformation of clay minerals in brackish and marine environments
Authors: Jeans C. V. 
Published: December 2006

AbstractIt is suggested (1) that large amounts of Al, Fe and Si carried in solution by fresh water are chemically precipitated as hydroxide gels in the brackish water environment of estuaries and deltas, and (2) that these gels are subsequently deposited in both the brackish water environment and in the neighbouring seas, where they become parental material for the neoformation of clay minerals, and various other silicate and iron minerals. The types of neoformed minerals will depend upon both the composition of the parental gels and the physico-chemical milieu of their crystallization. Evidence is discussed supporting this hypothesis from the following sources (1) the concentrations of Al, Fe and Si dissolved in fresh water and in sea-water, (2) experimental work on the crystallization of alumino-siliceous gels, and (3) a study of the precipitation of Si from the waters of the Mississippi River delta.Because of the unusual sediment pattern of present times, this source of neoformed clay minerals and other minerals contributes only a small proportion of the sediments of the brackish parts of estuaries, deltas and the adjacent seas, which are dominated by fine-grained continental detritus. In earlier geological eras, when the world's river systems carried only relatively minor amounts of fine-grained continental detritus, this source of neoformed minerals is likely to have contributed a considerable proportion of the fine-grained sediments of these areas of sedimentation. Three possible examples are discussed.
Hydrothermal and dry-heat fixation of K by soil clays and the effects on C.E.C., surface area and mineralogy
Authors: Davis C. E. , Ahmad N. , Jones R. L. 
Published: December 2006

AbstractFixation of K by soil clays and selected reference clay minerals was induced by dry heat and hydrothermal procedures, at 100°C, 200°C and 380°C. Appreciable amounts were fixed at all temperatures. In the cases of the samples treated hydrothermally the amounts fixed increased with pressure.Fixation by dry heating at 380°C was significantly greater than at 100°C and 200°C respectively. Fixation under hydrothermal conditions increased in order 380°C > 200°C > 100°C.Reductions in cation exchange capacities (and surface areas) were associated with fixation, indicating that some fixation was due to ion exchange. Changes in mineralogy in some of the samples also support the conclusion that ion exchange was partly responsible for fixation. Some of the fixation under hydrothermal conditions was due to the formation of insoluble K-compounds - as for example the synthesis of a new mineral when one sample was treated.The lattice-iron content of the clays may have influenced their hydrothermal behaviour. Thus the Princes Town Clay ( > 7-5 % lattice-iron) and three nontronites (≫ 7-5 % lattice-iron) showed appreciable lattice collapse after hydrothermal treatment, while Wyoming bentonite and hectorite (<3-5%) lattice-iron) showed no collapse at all.The degree of crystallinity of the mineral may also have influenced its hydrothermal reaction. For example, the highly disordered soil kaolinite (St John's) was much more reactive than the more ordered Georgia kaolinite. Also, the more-ordered reference clays fixed relatively less K at 380°C than the less-ordered soil clays.
Studies on the interaction of cationic surfactants with clay minerals
Authors: Malik W. U. , Srivastava S. K. , Gupta Devendra 
Published: December 2006

AbstractAdsorption and desorption of cationic surfactants, cetyl pyridinium bromide, cetyl trimethyl ammonium bromide, dodecyl pyridinium bromide on bentonite, kaolinite and illite, and their diffusion through a bentonite membrane have been studied.The binding of these compounds on the mineral surface takes place much beyond the exchange capacity. For excessive saturations with long chain compounds like these, the chains stand erect to the surface. A correlation of area per exchange site and area associated with surfactant molecule on clay surface also supports this view. The increase in the extent of adsorption with the size of the organic cation is due to an increase in the van der Waal's forces between clay and surfactant molecule. Isosteric heats of adsorption at different stages of surface covered with surfactant have also been determined and the same was found to pass through a minimum point. Larger ions desorb less, owing to the lesser solubility and larger contribution of dispersion forces.Permeability of these surfactants and energy of activation of the diffusion process through the H- bentonite membrane has also been investigated. Diffusion of these cations takes place via exchange positions through the membrane and the order is exactly the reverse of their adsorption on the clay surface.
Weathering of micaceous clays in some Norwegian podzols
Authors: Kapoor B. S. 
Published: December 2006

AbstractA study of the weathering of micaceous clays in some Norwegian podzols, includes semiquantitative estimates of minerals in the concentrated clay fractions which show a decrease in the amounts of illite and chlorite, and an increase in vermiculite and mixed-layer minerals upward in the profile. Illite, the dominant mineral at depth, weathers to hydrobiotite in the surface horizon of the profile. Subsequent weathering of hydrobiotite in this portion of the profile produces trioctahedral vermiculite and smectite, or intergrade smectite-chlorite.
A simple diffractometer heating stage
Authors: Brown G. , Edwards B. , Ormerod E. C. , Weir A. H. 
Published: December 2006

AbstractThe construction is described of a heating stage for examining oriented clay specimens in a Philips' diffractometer. The stage, which is simple and cheap to make, is interchangeable with standard specimen holders, operates over the range 20—265°C and does not require the diffractometer to be specially modified. The maximum temperature attained at the surface of the specimen collapses freely-expanding Mgsaturatcd vermiculite and prevents re-expansion of layer silicate minerals once they have been collapsed.
Acid character of nontronite: permanent and pH-dependent charge components of cation exchange capacity
Authors: Kapoor B. S. 
Published: December 2006

AbstractThe cation exchange capacity (C.E.C.) of nontronite was determined by titrating the acid clay, prepared by the action of H-resin on nontronite, in water and some nonaqueous solvents. The base-titratable acidities of the acid nontronite, freshly prepared as well as aged, were found to be greater than the acidities extractable with 1 N NaCl; the difference was attributed to the non-exchangeable pH-dependent component of C.E.C. In the freshly prepared sample, H+ and Fe3+ ions were the only exchangeable cations. Ageing produced basic Fe ions which were exchangeable and whose amount increased at the cost of H− and Fe3+ ions. Whatever the age, the total quantity of these exchangeable cations corresponding to the total isomorphous charge, remained constant. The amount of the pH-dependent acidity also remained unchanged. A likely mechanism to account for the observed pH-dependent component of the C.E.C, of nontronite is suggested.
The Vermiculitization of Trioctahedral Micas
Authors: Rousseaux J. M. , Rouxhet P. G. , Vielvoye L. A. , Herbillon A. J. 
Published: December 2006

AbstractThe alteration of thirty-nine trioctahedral micas to vermiculite has been characterized by the K level, which is determined by repeated measurements of the stationary K concentration in the altering solution and provides a practical way of comparing the sensitivity to alteration. A calculated regression equation allows the K level of a sample to be predicted from its chemical composition. The model proposed for the alteration reaction outlines the physico-chemical meaning of the K level, with its experimental and theoretical limitations.
Palygorskite from Warren Quarry, Enderby, Leicestershire, England
Authors: Tien Pei-Lin 
Published: December 2006

AbstractSpecimens of palygorskite from Warren Quarry, Enderby, Leicestershire, have been studied in the laboratories. The mineral is found in dioritic rocks in association with angular dolomitic rock fragments as the filling material of a joint, the walls of which are sometimes lined with calcite and dolomite. Palygorskite occurs as 3-10 mm long bundles of fibres, 0·03-0·1μm wide. X-ray diffraction data indicate that the mineral may occur in the monoclinic form. The structural formula for the half-unit cell is Si8(Al1.89Fe0.053+Ti0.01Mg1.99)O20(OH)2(OH2)43·61 H2O.Ca0.07. Data obtained from differential thermal and infrared analyses are comparable with those for palygorskite in the literature, but the six-sided transversal cross-section of the fibres as revealed by electron microscopy is unexpected. The mineral was formed after the deposition of the overlying basal Triassic rocks when ground waters penetrated cracks in the dioritic rocks, causing Si and Mg to be released there and above the unconformity.
The Formation of Hydroxy Interlayers in Smectites under the Influence of Organic Bases
Authors: Heller-Kallai L. , Yariv S. , Riemer M. 
Published: December 2006

AbstractSorption of molecular amines by montmorillonite involves protonation of the amine group and hydrolysis of the interlayer cation. Sorption and subsequent desorption of amines may render some of the interlayer cations non-exchangeable, thus causing partial 'chloritization' of the montmorillonite. The effect is stronger with interlayer Al than Ca ions and depends upon the amine sorbed.
Activation of Non-Swelling Bentonite
Authors: Bleifuss R. L. 
Published: December 2006

AbstractExamination of field samples shows that the alteration of the bentonite beds of Wyoming and Montana near the surface to produce high-quality, highswelling, commercial bentonites is analogous to pedocal soil development. The near surface bentonite has undergone extensive calcification, and in some zones it is so heavily altered as to diminish its swelling properties. These low-swelling bentonites can be activated by conventional soda-ash additions. The naturally high-swelling materials have undergone only partial calcification and do not require soda-ash modification. The relatively unaltered 'grey' or 'blue' bentonites have undergone little or no calcification. The latter have the highest Na to Ca ratios, are non-swelling, and do not respond markedly to soda-ash additions. Such low-swelling materials will respond to calcium-activation with markedly improved physical quality parameters of flocculation as measured by Marsh Funnel and Fann viscosimeter. The study indicates that vast reserves of low-swelling bentonites in Montana-Wyoming may be susceptible to controlled calcium activation and expanded commercial utilization.
The Adsorption of Aromatic, Heterocyclic and Cyclic Ammonium Cations by Montmorillonite
Authors: Vansant E. F. , Uytterhoeven J. B. 
Published: December 2006

AbstractThe adsorption of organic ions derived from ammonium, containing aromatic and saturated rings, was studied using different techniques. The ions with acid character produced a complicated set of reactions including aluminium extraction, proton adsorption, a real ion-exchange with the organic ions and an excess adsorption of ammonium salts. With non-acidic compounds only a stoichiometric ion-exchange process was observed. X-ray diffraction and infrared spectroscopy were used to determine the orientation of the organic ions and to characterize the nature of the co-adsorbed organic material.
The Formation of 2:1–2:2 Intergrade Clays in some Norwegian Podzols
Authors: Kapoor B. S. 
Published: December 2006

AbstractThe distribution of 2:1-2:2 intergrade clays has been investigated in some podzolized soils from Norway. In some of the profiles the intergrade clay mineral appears to be concentrated in the A2 horizon; in others, where smectite is predominant in the surface horizon, the maximum accumulation of the intergrade is observed in the B2 horizon. Smectite and vermiculite have been found to be the precursors of the intergrades of the A2 and B2 horizons respectively. A possible explanation to account for the observed variable pattern of occurrence of intergrades in soils is suggested.
The Clay Mineralogy of the Haldon Gravels
Authors: Hamblin R. J. O. 
Published: December 2006

AbstractThe less than 10 μm and less than 3 μm fractions of the heterogenous Haldon Gravels have been examined by X-ray diffractometry. Kaolinite of high to low crystallinity is the dominant clay mineral, with variable amounts of illite (clay mica) ; quartz, a little feldspar and anatase also occur. The kaolinite has been ranked using the crystallinity index of Hinckley and also by indices derived from the ratio of peak height to background height for the 10 and 11 peaks.Clay from the matrix of the psaphitic members of the Buller's Hill Gravel contains intermediate grade kaolinite with a little illite, but clay bodies included in this formation contain only low grade kaolinite with a high, but variable proportion of illite. The Tower Wood Gravel contains two distinct populations; one is identical to that of the Buller's Hill Gravel, the other consists of high crystallinity kaolinite with a little illite. Head Gravel formed from the Buller's Hill Gravel by solifluction contains intermediate to low crystallinity kaolinite.
Thickening Flocculated Kaolinite Slurries in the Nozzle Discharge, Multidisc, Bowl Centrifuge
Authors: Brociner R. E. , Vollans E. C. 
Published: December 2006

AbstractThree semi-empirical equations are derived to characterize the performance of the nozzle discharge centrifuge as a thickener for flocculated kaolinite slurries. The first equation relates mass throughput to machine size and speed, the number and size of nozzles and the product concentration. The second equation relates the maximum clear effluent rate to the settling characteristics of the slurry and to machine parameters. The third equation relates power consumption to product and effluent rates and to machine parameters. Finally a numerical example of the use of the equations is given.
The Alteration Characteristics of the Lower Oxford Clay
Authors: Jackson J. O. 
Published: December 2006

AbstractAlternating 'hard' and 'soft' bands at close intervals are exhibited by the slope faces of brick-pits in the Lower Oxford Clay which have been subjected to prolonged exposure. This phenomenon was investigated to evaluate the geotechnical properties which were significant in its development. The results of laboratory tests indicate that the alteration or short-term weathering characteristics of clay-shales may be influenced by the higher degree of preferred orientation of the clay-mineral component, in inducing a stronger inter-particle bond in 'hard' samples which inhibits weathering.