bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low-Angle X-Ray Diffraction Studies of the Swelling of Montmorillonite and Vermiculite
Authors: Norrish K. , Rausell-Colom J. A. 
Published: August 2006

AbstractVarious workers have studied the mechanism of swelling of Na-montmorillonite and have demonstrated that its ability to swell is due to water penetrating between the individual silicate sheets. In the present study intraerystalline swelling was followed by diffraction techniques which enabled the movement of the silicate sheets with respect to one another to be measured as a function of electrolyte concentration, with or without an externally applied load. The observations have been made on oriented flakes of Na-montmorillonite and single crystals of Li-vermiculite.Qualitatively the minerals behave similarly when swollen in salt solutions. They both show an initial stage of crystalline swelling, after which there is an explosive increase to the gel state, and then the distance apart of the silicate sheets increases linearly with C-½, where C is electrolyte concentration. Quantitatively, however, their swelling is very different, particularly after the “explosion”, where vermiculite generally gives higher spacings than montmorillonite. There are two other important differences in the swelling of montmorillonite and vermiculite. Firstly, while the swelling of vermiculite appears to be reversible both with respect to electrolyte concentration and applied pressure, the swelling of montmorillonite shows a marked hysteresis. Secondly, in montmorillonite, swelling depends very strongly on pH or chemical treatment.There is little doubt that the development of diffuse “double layers” gives rise to repulsive forces, which cause the silicate sheets to move apart. Van der Waals’ forces have been regarded as providing attraction, but it is found that, at the observed interlayer separations, the magnitude of these attractive forces is inadequate to balance repulsion, both in montmorillonite and vermiculite.The present results demonstrate that in vermiculite swelling proceeds until the interlayer separation causes the repulsion between sheets to drop to a value of ~ 2.5 × 104 dyn/cm2. This attractive force, which limits swelling, appears to be independent of sheet separation and electrolyte concentration. In montmorillonite swelling is opposed by edge-to-face bonds between sheets, whose number and strength can be controlled by chemical treatment. These bonds act to resist any displacement of the sheets, either swelling or contraction. This mechanism is compatible with the observed swelling behavior of montmorillonite, and explains the differences between the swelling of this mineral and that of vermiculite where, because the sheets are considerably larger, the force arising from edge-to-face bonds is small or absent.
Characterization of Montmorillonite Saturated with Short-Chain Amine Cations: 1. Interpretation of Basal Spacing Measurements
Authors: Diamond Sidney , Kinter Earl B. 
Published: August 2006

AbstractBasal spacing measurements were made for a montmorillonite saturated with a series of small aliphatic primary, secondary, and tertiary amine and quaternary ammonium cations, using wet, oven-dry, and glycerol-treated specimens. The spacings ranged from about 12 to 14Å, depending on the cation, indicating that in each case a monolayer of cations is interleaved between adjacent montmorillonite layers. The observed spacings are consistent with the concept that the cations are oriented with their minimum thickness in the c-axis direction, but it is possible that the smallest cations have a long axis in this direction and are partially embedded in the clay surfaces.Montmorillonite saturated with cations containing up to four carbon atoms retained some sensitivity to water, as indicated by a slight contraction of the lattice on oven drying and rapid re-expansion on exposure to the humidity of the laboratory atmosphere.For cations having a layer thickness less than glycerol, limited lattice expansion occurred on glycerol treatment, usually to a spacing sufficient to accommodate a single layer of glycerol molecules. Apparently the cations function as pillars separating the montmorillonite layers, and the glycerol molecules may expand the lattice as necessary to enter the spaces between the pillars. However, exceptions occurred with methylamine-saturated montmorillonite, in which both one- and two-layer complexes of glycerol were present simultaneously in the same specimen, and with trimethylamine-saturated clay, in which two different one-layer complexes were present. It is suggested that the glycerol in one-layer montmorillonite complexes may exist in two orientations, one leading to a layer thickness of about 4.1 Å, the other to a thickness of about 4.6 Å.
Mica-Type Layer Silicates with Alkylammonium Ions
Authors: Weiss Armin 
Published: August 2006

AbstractMore than 8000 different derivatives of mica-type layer silicates (muscovite, biotite, illite, vermiculite, beidellite, montmorillonite) with alkylammonium ions and different organic molecules as swelling liquids were prepared and characterized analytically by X-ray and chemical methods. The following results have been discussed in some detail.Layer-lattice compounds are formed in simple stoichiometric relations. In n-alkyl-ammonium compounds, for instance, the sum (n-Cx,H2x+1NH3++n-CxH2x+1Y) per (Si, Al)4O10 is equal to 2.0 (Y = OH-, Cl-, Br-, NH2-, COH-, CONH2-, CN-).The layer distance of the pure n-alkylammonium derivatives enables one to determine the charge density in the silicate layers. But in soils the ability of humic acids to undergo two-dimensional intracrystalline swelling and to react with alkylammonium ions must also be considered.The properties of n-alkylammonium layer silicates are similar to those of alkyl-ammonium-uranium micas and of swelling vanadates (e.g. hewettite and pascoite). The swelling properties of alkyl-(α, ω)-diammonium ions are markedly influenced by the opportunities for hydrogen bonding. Mica-type layer silicates may show catalytic properties like protease or oxidase with ammonium ions, which are of general interest.
Adsorption by Organo-Clay Complexes—Part 2
Authors: Cowan C. T. 
Published: August 2006

AbstractA detailed investigation of the adsorption of phenol and m-cresol from dilute aqueous solution by dodecyl- and tetradecylammonium bentonites has been carried out. The Freundlich isotherms for the tetradecylammonium bentonite system indicate that during adsorption, the process proceeds in two stages, the partial molar heat of adsorption changing from a positive to a negative value with a relatively small change in concentration of adsorbate. In the light of these findings, the aspects of the adsorption are discussed in terms of thermodynamic quantities, spatial considerations, and interlamellar expansion of the clay mineral.
X-Ray Diffraction Studies of Organic Cation-Stabilized Bentoniteby
Authors: Rosauer E. A. , Handy R. L. , Demirel Turgut 
Published: August 2006

AbstractStudies of quaternary ammonium chlorides containing long unsaturated hydrocarbon chains have shown their effectiveness in stabilizing soils primarily by waterproofing the clay fraction. The nature of the interaction between organic salts and Wyoming bentonite was studied by means of X-ray diffraction.Treatment of bentonite with a dialkyl dimethyl ammonium salt in an amount less than the exchange capacity results in the appearance of water-stable spacings of 10, 13 and 19 Å, but only if the sample has been dry cured. Moist curing a bentonite paste results in a marked expansion of the lattice despite treatment. The necessity of dry curing may relate to orientation of organic cations around bentonite aggregates; grinding prior to rewetting destroys the waterproofing action, and the clay lattice again expands.Additions of the quaternary ammonium cations close to or in excess of the exchange capacity of the bentonite waterproofs regardless of dry curing or grinding, or both. Clays treated in this manner show spacings of the pure crystalline chemicals and other spacings which relate to interlayer penetration by water. There is no direct evidence for interlayer penetration by the organic cation, perhaps because of the unwieldy tetra-hedral arrangement of the organic molecule. The degree to which organic cations are held depends on the nature of the surface as the cations are readily leached from quartz powder but are held more strongly on kaolinite and bentonite.
Perspectives in Applied Organo-Clay Chemistry
Authors: Nahin Paul G. 
Published: August 2006

AbstractSome aspects of organo-clay chemistry that have interested a growing number of scientists are reviewed and discussed. Particular attention is directed to published evidence for the “reality” of clay compounds, the possible effects of high energy radiation on clay properties, industrial applications of modified clays and the increasing number of patents being granted in this field of applied chemistry. A number of areas of inadequate information where further basic research could lead to useful applications is pointed out.
Attapulgite: Properties and Uses
Authors: Haden W. L. 
Published: August 2006

AbstractThe clay mineral attapulgite derives its non-swelling needle-like morphology from its three-dimensional crystal structure. The shape and size of the needles result in unique colloidal properties, especially resistance to high concentrations of electrolytes, and give high surface area, high porosity particles when thermally activated. Examples of industrial applications of attapulgite are reviewed with emphasis on how these characteristic properties function in the various end-uses.
Organophilic Clay-Base Thickeners
Authors: Jordan J. W. 
Published: August 2006

AbstractThe clay minerals, generally characterized by their small particle size, affinity for water, and response to chemical changes in their environment, are noted for their gelling and viscosity-increasing abilities in aqueous systems. Rendered organophilic by association with long-ohain organic compounds, several of the clay minerals exhibit similar or even greater gelling abilities in various organic liquids.Methods of preparing organophilic clays are discussed and data shown for ion exchange reactions between long-chain organic cations and montmorillonite minerals. Properties of modified clays in various liquid systems are illustrated, and industrial applications are cited.
Density Studies in Clay—Liquid Systems, Part II: Application to Core Analysis
Authors: Deeds C. T. , van Olphen H. 
Published: August 2006

AbstractIn Part I (Deeds and van Olphen, 1961) pycnometric data on expanding clays in water and in other displacement fluids were analyzed in terms of inaccessible void space within aggregates and of possible density anomalies of the adsorbed fraction of the displacement fluids.Further details of this work are reported, and the consequences for the interpretation of core analysis data are discussed. It is concluded that in core analysis the density of the connate water can be assumed to be normal while the fraction of the total pore space which is filled with oil is computed, provided that the total pore space is determined by using water or a polar organic liquid. If a hydrocarbon liquid or an inert gas is used, a small correction for inaccessible pore space can be applied.
Diagenesis of Clays in Sedimentary and Petroliferous Series
Authors: Kulbicki Georges , Millot Georges 
Published: August 2006

AbstractIn the argillaceous fraction of a sedimentary series of petroliferous sandstones from the Sahara two successive diagenetic changes are considered. The first is kaolinization of the original silicates. This is followed by illitization of the kaolinite by saline waters. The same formation is kaolinitic where it produces petroleum and illitic where it is nonproductive.
Effect of Radiation Damage on Mullite Formation in Kaolinite
Authors: Head C. M. , Moody W. E. , Mitchell Lane , Young R. A. 
Published: August 2006

AbstractKaolin was irradiated with 0.67 meV gamma-rays from a Cs137 source. Irradiation dosages of more than 1019 eV/g retarded mullite formation whereas smaller dosages appeared to have enhanced mullite formation slightly. It appears that preferentially oriented mullite formation from kaolinite is energetically favored and is adversely affected by radiation-produced nb/3 shifting of the Al ions. A possible mechanism for the effects of the radiation on mullite formation is suggested.
Proposed Reference Illite from the Ouachita Mountains of Southeastern Oklahoma
Authors: Mankin C. J. , Dodd C. G. 
Published: August 2006

AbstractAn exceptionally pure illitic clay is present in outcrops of the Blaylock Formation (Silurian) in the Ouachita Mountains of southeastern Oklahoma. Unweathered claystone samples from this unit in Beavers Bend State Park have been found to consist of a well-crystallized illite or hydrous mica. Impurities commonly found in illites such as non-clay minerals and non-micaceous clay minerals are conspicuously absent. The sample cannot be classified as a mica because it is hydrated and the particle-size distribution is in the clay size range. A detailed examination of the deposit suggests that it may have value as a reference illitic clay mineral.
Research on Evolution of Clay Minerals and Argillaceous and Siliceous Neoformation
Authors: Millot Georges , Lucas Jacques , Wey Raymond 
Published: August 2006

AbstractThe following recent work is reviewed.In the Triassic basin of the Jura detrital illite changes into chlorite (chlorite and chloritie mixed layers) toward the middle of the basin.In the profiles of podzolic soils and podzols, illite and chlorite change, through illite— vermiculite and chlorite-vermiculite stages, into vermiculite.In Cambrian sandstones of the Sahara two successive diagenetic changes have taken place: early postdepositional kaolinization, and illitization by salt waters.Neoformation of aluminomagnesian clays in the alkaline sediments of the Eocene basins in Africa produces a sedimentary and geochemical sequence of montmorillonite, attapulgite and sepiolite.When siliceous neoformation is produced by crystal growth, the growth is regular in the production of quartz, and irregular or hindered in the formation of chalcedony or opal-cristobalite.Kaolinite has been synthesized at low temperatures in dilute solutions.Transformations of triphormic clay minerals in the hydrosphere consist of a progressive expansion of layers. Environment controls the equilibrium between interlayer cations and adjacent layers. Siliceous and argillaceous neoformation consists of organization of silica tetrahedrons; this organization depends on the environment and especially on the environmental cations. Transformation by diagenesis is more intense and allows direct passage from illite to kaolinite.
Research Work on Clay Minerals and Argillaceous Rocks in Czechoslovakia
Authors: Konta Jiří 
Published: August 2006

AbstractThe investigation of clay minerals and argillaceous rocks started in the territory of Czechoslovakia as early as the later part of the eighteenth century and has continued up to today. During this long period many interesting results have been obtained. In about 1949 modern laboratory techniques were introduced. Most of the work in this country deals with the mineralogy, petrology, and geology of argillaceous rocks, the chemical composition and physical properties of clay materials which are useful for the purposes of the ceramic, glass, chemical, construction-engineering and mining industries, etc. This paper is subdivided into the following parts: (a) Classical research period; (b) Modern research period; (c) Kaolins (primary); (d) Other argillaceous rocks of sedimentary origin; (e) Bentonites; (f) Laterites and bauxitic rocks; (g) Clay minerals in sedimentary iron ores; (h) Clay minerals in carbonaceous rocks; (i) Clay minerals of hydro-thermal origin; (j) Kinds of apparatus for DTA and gravimetric thermal analysis; (k) Imbibometric study using water and organic liquids; (1) Problems of classification and terminology.
De Natura Lutorum
Authors: Mackenzie R. C. 
Published: August 2006

AbstractDespite recent advances in clay mineralogy there is still no generally accepted definition of the terms clays and clay minerals. This problem is discussed from the historical aspect: the similarities of definitions given from the 16th century to the present are remarkable and lead one to consider whether possible simple modifications might not eventuate in some measure of universal agreement. Comparison of nomenclature and classification schemes shows that from the time of Theophrastus to that of Agricola there appears to have been little advance, but a change becomes noticeable by the end of the 18th century, and by the end of the 19th old names, such as porcelain clay, etc., have given place to what are now regarded as names of mineral species or varieties. Only after the 1920’s have satisfactory groupings been obtained, but no internationally acceptable classification has yet been devised. Finally, the various factors operative during clay formation by weathering and diagenesis are discussed, and it is stressed that field and laboratory studies are complementary.
Interlayering of Expansible Layer Silicates in Soils by Chemical Weathering
Authors: Jackson M. L. 
Published: August 2006

AbstractInterlayering of 2: 1 layer silicates varies as a function of chemical weathering from the simple, homogeneous K or Na interlayers of micas to the heterogeneous systems of mica intercalated with expanded 2: 1 layer silicates. “Frayed edge” type of weathering at dislocation planes of mica is collated with K release and preferential cation-exchange uptake of K relative to Ca by such expansible layer silicate systems; mica islands maintain alignment of the silica sheet cavities, which facilitates recapture of lattice K. Intercalation of the expanded 2: 1 layer silicates with alumina interlayers appears to be a characteristic function of chemical weathering in soils, with the formation of 2: 1–2: 2 intergrades not only of 14 Å spacing but also of swelling 18 Å types that give small 12, 14, 18 Å and higher spacing peaks (along with the 10 Å peak) at 550°C. Interlayer precipitates appear to be characteristic of soil clays, contrasting with “pure” minerals of deposits developed in less “open” environments than those of soils. The “2: 2 lattice building” phenomenon in expansible 2: 1 layer silicates relates to layer charge density and crystal size, and frequently tends to inhibit the formation of free gibbsite in soil chemical weathering so long as there are expansible layer silicates present to become intercalated with aluminum hydroxide—a weathering phenomenon that may be called an “antigibbsite effect”. Accumulation of alumina (possibly with some iron, magnesium, and allophane) as interlayers in 2: 1 minerals of soils is seen as a genetic stage in the 2: 2 → 1: 1 weathering sequence through which kaolinite and halloysite develop in soils.
Negative Charge of Dioctahedral Micas as Related to Weathering
Authors: Cook M. G. , Rich C. I. 
Published: August 2006

AbstractNegative charge and related characteristics of dioctahedral micas have been investigated by conducting artificial weathering studies on a muscovite from Ontario, Canada, and saprolitic micas from Virginia. Emphasis is given to the relationship between loss of potassium, increase in net negative charge, or cation exchange capacity, and expansion characteristics.Boiling solutions of acetic acid, sodium chloride and magnesium chloride removed potassium and sodium from a saprolitic mica but produced a negligible increase in cation exchange capacity. Expansion of the mica structure occurred following treatment with salt solutions but not with acid solutions. Boiling solutions of sodium citrate removed potassium effectively, produced marked expansion, and caused a large increase in cation exchange capacity. The small increase in cation exchange capacity resulting from acid and salt treatments is attributed to the hydrolysis of exchangeable aluminum to form hydroxy-aluminum polymeric groups, which can occupy exchange sites but remain non-exchangeable. The results of the sodium citrate tratement are attributed to the complexing of aluminum by citrate, thus releasing the hydroxy-aluminum polymeric groups from exchange positions and permitting an increase in cation exchange capacity.Molten lithium nitrate treatment of specimen muscovite produced a greater increase in cation exchange capacity than in the case of muscovite separated from soil-forming mica phyllite. The observed difference in charge characteristics, concomitant with the greater expansion of the muscovite, suggest that soil micas and specimen-type micas differ in their alteration tendencies.When interlayer hydroxy groups are eliminated and account is taken of residual sodium, potassium, and water, dioctahedral micas apparently lose no negative charge on expansion to vermiculite-like minerals.
Weathering of Stone Mountain Granite
Authors: Grant Willard H. 
Published: August 2006

AbstractThe weathering of Stone Mountain Granite (adamellite) forms kaolinite, endellite, allophane and gibbsite of which kaolinite is the most stable. Bulk density ranges from 2.65 in fresh rock to a minimum of 1.48 in saprolite. It is a good index of weathering. Abrasion pH ranges from 5.0 in saprolite to 9.3 in fresh rock, and is directly related to bulk density and the amount of clay mineral. Among the original minerals, biotite is least stable, followed by oligoclase. Residual microcline fragments occur at the base of the B horizon indicating that it is not completely weathered. Muscovite weathers slightly and quartz appears quite stable.Evidence shows that solution and reconstitution is necessary in the formation of some if not all clay minerals. This is particularly evident in the formation of endellite veins.Expansion of the rock in the early phases of weathering occurs but does not produce a significant increase in volume.
Characteristics of 14 Å Clay Minerals in the B Horizons of Podzolized Soils of Alberta
Authors: Pawluk S. 
Published: August 2006

AbstractRecent investigations of soils from widely distributed sites reveal the presence of clay minerals with 14 Å d spacings in the B horizons of podzolized soils in Alberta. The minerals appear to be concentrated in the 2.0–0.2 micron clay fraction, the fraction less than 0.2 micron being comprised primarily of material amorphous to X-ray. Despite the presence of montmorillonite in the eluvial horizon and soil parent material only interstratified minerals of this group appear in association with the 14 Å mineral. Smaller amounts of quartz, kaolinite and illite are also noted in these B horizons.The data available reveal that the 14 Å mineral is derived from montmorillonite and that formation occurs in situ in the B horizons.It is apparent from the investigations conducted that weathering of associated feldspars under mildly acid conditions, releases hydrated alumina ions. These ions not only move into the interlayer regions of montmorillonite of fine clay size, where they exist in a discontinuous manner, but are also adsorbed onto the surfaces of these minerals binding adjacent particles into aggregates of coarse clay size. Adsorbed hydrated alumina hydroxy ions in the interlayer region are responsible for the observed 14 Å d spacings.
Solid-Gas Interface in Weathering Reactions
Authors: Wayman Cooper H. 
Published: August 2006

AbstractMost weathering reactions have been interpreted in terms of the solid-liquid interface. In dry climates or at low humidity, weathering might be initiated or controlled by a solid-gas reaction. The stability of gibbsite and some hydrous borates involves the activity of water vapor; and the stability of azurite depends on a ratio of the partial pressures of both water vapor and carbon dioxide. Much additional work is required on the rates of equilibrium dehydration to contribute to our knowledge of the solid-gas interface in weathering.