bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cationic Diffusion in Clay Minerals: II. Orientation Effects
Authors: Lai T. M. , Mortland M. M. 
Published: August 2006

AbstractThe effect of orientation of vermiculite particles on the diffusion of Na ion was measured by a tracer technique. The diffusion measurements were made on pellets prepared by pressing freezedried vermiculite in a cylindrical die and the diffusion coefficient evaluated by a thin-film boundary condition of Fick’s law. Because flakes of vermiculite were highly oriented under the pressing force, it was possible to prepare different angles of specimen orientation with respect to the surface where diffusion was initiated. Mathematical relationships of orientation angle, axial ratio of the platelets, and apparent diffusion coefficient were developed. The experimental results on the diffusion of Na ion in K-vermiculite of clay size gave apparent diffusion coefficients of 2·21 × 107cm2 sec−1 when the diffusion flux was parallel with the clay platelets and 0·45 × 10−7 cm2 sec “1 when the flux was perpendicular to the clay platelets. For the diffusion of Na ion into Na-vermiculite, apparent diffusion coefficients were obtained of 1·18 × 10−8cm2sec−1 when the diffusion flux was parallel with the clay platelets, and 0·18 × 10−8 cm2 sec−1 when the flux was perpendicular to the platelets. For K-vermiculite, the change in apparent diffusion coefficient is a simple one of particle geometry. The Na-vermiculite system exhibited more complicated behavior.
Aluminum Interlayers in Layer Silicates Effect of OH/Al Ratio of Al Solution, Time of Reaction, and Type of Structure
Authors: Sawhney B. L. 
Published: August 2006

AbstractAluminum interlayers were synthesized under the same experimental conditions in a number of vermiculites and montmorillonites from different sources to determine the effects of the degree of neutralization of Al solutions, the time of reaction, and the type of structure.Vermiculite fixed Al as well as hydroxy-Al ions in its interlayers, producing a stable 14 Å spacing and decreasing its cation exchange capacity considerably. Heating the Al-interlayered vermiculite at 300°C produced an interstratified mixture, indicating that some interlayers collapsed while others did not. The different collapse was attributed to different charge on vermiculite layers.Neither the aging of vermiculite in Al solutions nor their OH/A1 ratios changed the stability of the interlayers appreciably.Montmorillonites, on the other hand, did not fix Al ions but fixed appreciable amounts of hydroxy-Al ions. In addition, the stability of the interlayers in montmorillonite increased on aging in hydroxy-Al solutions and exceeded the stability of the interlayers produced in vermiculite. To explain the greater stability of montmorillonite interlayers, it was postulated that the more expanded interlayer space in montmorillonite provides a favorable locale for the organization of hydroxy-Al ions into gibbsite structure while the restricted expansion in vermiculite prevents it.
Retention of Crude Oil Bases by Clay-Containing Sandstone
Authors: Reed M. G. 
Published: August 2006

AbstractRetention of basic components of a crude oil by clay-containing reservoir sandstone was studied by flowing crude oil through cores and monitoring the concentration of bases in the effluent. Cores that were H-saturated, H-saturated then aged, and Na-saturated retained 0·82, 0·82, 0·70, and 0·20 meq base/100 g, respectively. Barium exchange capacity values were 0·86, 0·71, and 0·83 meq/100 g. Subsequent floods with water, toluene, and chloroform-acetone removed oil that had increasing concentrations of base and N, indicating that the basic fraction of crude oil was the most difficult fraction to extract from clay mineral surfaces. Retained bases were nitrogenous and the most tenaciously held bases had base/N ratios approaching unity.
Electron Microprobe Study of Kaolin
Authors: Weaver Charles E. 
Published: August 2006

AbstractElectron microprobe studies of kaolinite indicate that most of the Fe is evenly distributed throughout the kaolinite and must either be in the structure or occur as very small particles adsorbed on the surface. In addition to Ti the anatase impurities contain Fe and Mg. Fe, Mg, Mn, V, and K are present in biotite. It is necessary to concentrate the fine-grained mineral impurities in order to study them with the electron microprobe.
Absorption of Pyrimidines, Purines, and Nucleosides by Co-, Ni-, Cu-, and Fe(III)-Montmorillonite (Clay-Organic Studies XIII)
Authors: Lailach G. E. , Thompson T. D. , Brindley G. W. 
Published: August 2006

AbstractAbsorptions of purine and pyrimidine derivatives by Co- and Ni- montmorillonite at pH < 6 and by Cu-montmorillonite at pH < 3 are similar to their absorption by Ca-montmorillonite and take place primarily by a cation exchange process. In the weakly acidic to weakly alkaline range, absorption is due to complex formation with the inorganic cations, and decrease in the order Cu ≫ Ni > Co ≫ Ca. Adenine, 7-methyladenine, hypoxanthine, and purine are strongly absorbed, 9-methyladenine, 6-chloropurine, and cytosine are weakly absorbed, and thymine and uracil are not absorbed. At pH < 5, the nucleosides are absorbed by Co-, Ni-, and Cu-montmorillonite in approximately the same manner as by Ca-montmorillonite, but at pH > 6 their absorptions decrease in the order Cu ≫ Ni > Co > Ca. Fe(III)-montmorillonite behaves quite differently from the other mont-morillonites studied. With purines and pyrimidines, there is strong absorption from pH 3 to pH 7–8; with the nucleosides, the absorption varies considerably with the compounds considered decreasing in the order adenosine > cytidine ≫ guanosine ≫ inosine.
Heterogeneity of Montmorillonite Surface and Its Effect on the Nature of Hydroxy-Aluminum Interlayers
Authors: Hsu Pa Ho 
Published: August 2006

AbstractA specimen montmorillonite (Arizona bentonite) was treated with hydroxy-aluminum solutions of various basicity. The cation exchange sites of this clay were found not to be homogeneous in their strength of retaining hydroxy-aluminum polymers; this strength varied from very weak, with which the Al polymers were only loosely held, to very strong, with which stable interlayer Al-clay complexes were formed. When a large amount of clay was treated with a small amount of solution, the polymers were held only in positions of strong affinity; the polymers were difficult to extract with neutral salt solutions and did not change to crystalline Al(OH)3 during prolonged aging. When a small amount of clay was treated with a large amount of solution, the exchange sites were completely occupied by polymers; a portion of these polymers was easily extractable with neutral salt solutions and, during aging, changed to Al(OH)3. This contrast is significant in any attempt to compare results obtained under different experimental conditions and to correlate laboratory experimentation with the occurrence of gibbsite and interlayer Al-clay complexes in nature.
Quantitative Analysis of Naturally Occurring Multicomponent Mineral Systems by X-Ray Diffraction
Authors: Moore Charles A. 
Published: August 2006

AbstractA theory for the quantitative analysis of multicomponent mineral systems by means of X-ray diffraction is presented. A linear interaction between mineral pairs is postulated. The theory is verified experimentally for bicomponent and tricomponent systems using a variety of sample preparation techniques including random powder mounts, suspensions sedimented onto glass slides, and pressed powder pellets. The minerals studied include quartz, fluorite, kaolinite, glauconite, illite, and montmorillonite.The determination of the linear interaction factors for mineral pairs is treated theoretically and experimentally. Emphasis is placed upon techniques that are applicable to naturally occurring mineral systems. Four approaches are presented for determining linear interaction coefficients for various types of such mineral systems. These approaches are applied to the experimental data and the results are compared. Results accurate within 2 per cent are commonly obtained.Experimental techniques are discussed and a qualitative and quantitative error analysis is presented. It is shown that the indicated quantities present may not be particularly sensitive to the value of the linear interaction coefficient.
Analysis Of Iron In Layer Silicates By Mossbauer Spectroscopy
Authors: Taylor G. L. , Ruotsala A. P. , Keeling R. O. 
Published: August 2006

AbstractAnalysis of Mossbauer effect in layer silicates provides a spectroscopic method for determining valences and coordination of iron. In this study Mossbauer spectra were obtained for amesite, cronstedtite, nontronite, two glauconites, biotite, lepidomelane, chlorite, minnesotaite, vermiculite. stilpnomelane, and chloritoid.Trivalent iron was detected in tetrahedral coordination. Abundant trivalent iron in octahedral coordination apparently causes quadrupole splitting values of divalent iron in the same mineral to decrease. This phenomenon was noted in cronstedtite and glauconite. In cases where divalent iron predominates in the mineral, the quadrupole splitting is larger. It is generally accepted that ferrous iron is largely in octahedral coordination. This suggests that the octahedral sites may be more distorted when ferric iron is present in the octahedral sheet. In biotite, quadrupole splitting of divalent iron is decreased when trivalent iron is present in tetrahedral sheets. This suggests that there is also more distortion in the octahedral sheet because of iron in tetrahedral positions.
Sealing Properties of Bentonite Suspensions
Authors: Rollins M. B. 
Published: August 2006

AbstractSealing with waterborne clays is a rapid and low cost method of controlling seepage through porous media whenever the clay source is within economical shipping distance of the sealing site. But more must be learned about this method of sealing before it can be fully utilized.Water impedance of waterborne bentonites, as measured by water loss in the filter press test, was correlated with their physical, chemical and mineralogical properties. A multiple linear regression analysis showed clay content and exchangeable sodium percentage (ESP) were most highly correlated with water impedance. Swelling, viscosity and gelation of these clays play only a secondary role in forming a water barrier when used as dilute waterborne sealants as suggested by these and other data.There were strong positive correlations between water loss and samples high in silt-sized cristobalite, quartz and feldspar; and negative correlations between water loss and samples high in clay-sized montmorillonite, chlorite and illite.Predicted minimum clay contents (of prospective sealers) were found to be 65–75 per cent clay at 70 and 20 per cent exchangeable sodium, respectively.
The Nature of Anauxite
Authors: Langston Robert B. , Pask Joseph A. 
Published: August 2006

AbstractAnauxite crystals are reported to contain a higher SiO2:Al2O3 ratio than the 2:1 ratio found in kaolinite. A structure proposed for anauxite places the excess silica in double silica sheets, but an exact structure for anauxite has never specifically been determined. Many workers believe that anauxite is kaolinite associated with some extremely fine-grained excess silica which is not a part of the structure. Eight specimens studied in this work included portions of type materials from Bilin, Czechoslovakia, and the lone formation in California.Amorphous silica and alumina are readily soluble in boiling (N/2)NaOH. Kaolinite is only slowly soluble in this reagent, but becomes readily soluble after dehydroxylation. Weight loss, differential solution rate, kinetic and X-ray diffraction studies were used to establish that the kaolinite clay fraction in the anauxite specimens had the composition of:\$\end{document}Some of the anauxite grains are single crystals, while others are aggregates. The latter appear to be bound together by an amorphous silica phase. Hot caustic leaching extracts the amorphous silica and breaks up the aggregates producing “fines.” Improved characterizations of minor impurities were obtained when the residues from hot caustic treatments were studied with X-ray diffraction techniques.
Hydrothermal Argillation of Volcanic Pipes in Limestone in Mexico
Authors: Keller W. D. , Hanson Robert F. 
Published: August 2006

AbstractPreviously reported deposits of kaolin of hydrothermal origin in Mexico have been described from igneous parent rocks dominantly extrusive in occurrence. Recently observed evidence from other localities confirms an intrusive mode of occurrence, however, for hydrothermally kaolinized agglomerate and tuff within limestone host rock. Three such occurrences have been recognized near Jasso-Calera, north of Mexico City, and near Coacoyula, Guerrero, and Sombrerete, Zacatecas.The contacts of these clay deposits with limestone show regularly a concentration of iron-rich minerals such as red to brown oxides and/or nontronite, but less commonly an irregular development of grossularite, and bands or pockets of endellite. Silica gossans indicate that hypogene altering solutions were active into the current geomorphic cycle. Kaolinite at the center of the clay body and endellite at the border zones are interpreted as originating, respectively, from in situ alteration of solid rock and deposition from ambient solutions.
Determination of Surface Area by Surfactant Adsorption in Aqueous Suspension — I. Dodecylamine Hydrochloride
Authors: Kalb G. William , Curry R. Bruce 
Published: August 2006

AbstractConductometric titrations of clay suspensions with surfactant solutions offer a rapid method of surface area determination of clay particles suspended in aqueous media. A cationic surfactant, dodecylamine hydrochloride, was used in this investigation. This surfactant was adsorbed by electrostatic bonding at cation exchange sites and by van der Waals forces. A monomolecular or bimolecular layer of the surfactant coats the particle and the completion of the layer is determined from a change in slope of the conductometric titration curve due to the formation of micelles. Good agreement between this method and BET determined values were obtained for kaolinite. The bentonite suspensions had a strong tendency to flocculate after the initial stage of adsorption causing the results to vary considerably. This method of surface area measurement of clay particles offers many advantages over the present techniques: (1) a dry particle is not required; (2) the equipment is inexpensive and available in many laboratories; (3) the method is rapid; (4) vacuum and high temperature are not required, and (5) the method measures the internal as well as external surface area.
Hydraulic and Electrical Flows in Clays
Authors: Arulanandan Kandiah 
Published: August 2006

AbstractThe electrical conductivity of saturated kaolinite clay-water-electrolyte systems of different particle size distributions and of illite and montmorillonite clays were determined over the frequency range of 50–108 c/s. The conductivity increases as the frequency increases, and the experimental values show two distinct dispersions, one in the low frequency range and the other in the high frequency range. The frequency range over which the first dispersion occurs is experimentally shown to be dependent on particle size. The average particle size is uniquely related to the frequency at which half the dispersion occurs. The magnitude of conductivity variation, the high frequency conductivity and the streaming potential values are related to the microscopic permeability coefficient. This microscopic permeability coefficient, evaluated from a knowledge of the above electrical properties, is shown to be uniquely related to the Darcy permeability coefficient at various consolidation states of the kaolinite clays. Similar unique relationships have been observed in illitic clays.
Complex Viscosity of a Kaolin Clay
Authors: Franklin Arley G. , Krizek Raymond J. 
Published: August 2006

AbstractThe complex viscosity of a material is a two-component quantity, comprising real and imaginary parts. The real part of the complex viscosity is often very useful because in many materials it approaches the ordinary steady-flow viscosity at low frequencies. Because many materials with high viscosities are very slow in reaching a steady-flow condition, the determination of the steady-flow viscosity may be very difficult; however, an approximation can often be obtained from low-frequency values of the real part of the complex viscosity. In this study, the complex viscosity of a Georgia kaolin has been determined by measurements made on specimens subjected to oscillatory simple shear, over three decades of frequency. Other independent variables in the study are the water content of the clay and the shear strain amplitude. Data were obtained from experimental measurements in the form of values of the magnitude, or absolute value, of the complex viscosity, and the phase angle between the imposed oscillatory strain and the stress response. Empirical functional relationships are developed to relate these quantities to the independent variables, and these are in turn used to obtain the real and imaginary parts of the complex viscosity as functions of the independent variables. The results of this study indicate that the complex viscosity is not linear, but decreases approximately as a power function of the strain amplitude; the relation between the complex viscosity and the water content is approximately an inverse logarithmic one, and changes very rapidly at water contents near the liquid limit; and the phase angle increases with increasing strain amplitude approximately as a power function.
Abrasion pH, an Index of Chemical Weathering
Authors: Grant Willard H. 
Published: August 2006

AbstractIf a series of rock samples with granitic composition in various stages of chemical weathering is ground in a mortar with distilled water and the pH of the slurry produced is determined, it will be evident that the pH declines as the weathering increases. This relationship can be made useful by plotting abrasion pH against some other index of weathering such as the percentage of clay mineral or the bulk density of the weathered rock. Factors controlling abrasion pH are the cations such as K, Na, Ca, and Mg and the amount of clay mineral present.
Kinetics of Acid-Dissolution of Palygorskite (Attapulgite) and Sepiolite
Authors: Abdul-Latif Numan , Weaver Charles E. 
Published: August 2006

AbstractPalygorskite and sepiolite were digested with large excesses of hydrochloric acid at constant temperature for various periods of time. The reaction was found to be of first order with respect to the magnesium, aluminum and iron components in the clay and also with respect to hydrochloric acid concentration.The reaction rate constant for Mg is larger than for Fe, which is larger than for Al. Approximately one-third of the octahedral-type cations are extraneous, suggesting that only three of the five octahedral positions are filled. The reaction rate constant of Mg in sepiolite is about 240 times that for palygorskite. This may be an indication that sepiolite is less stable to chemical weathering than palygorskite.The activation energies for Mg, Al and Fe in palygorskite were found to be the same and equal to about 18·4 kcal per mole.Treatment of partially acid-digested palygorskite with magnesium ions under alkaline conditions resulted in an increase in the X-ray intensity of the 10·5 Å spacing, suggesting some of the palygorskite was reconstituted.
New Data for Tosudite
Authors: Shimoda Susumu 
Published: August 2006

AbstractTosudite from the Takatama mine is found as an alteration mineral of the wall rocks (tuff and tuffaceous sediments of Tertiary age) of gold-silver-quartz veins. A specimen free from impurities was obtained by the sedimentation method. Chemical composition: SiO2 42·14%; Al2O3 37·38%; Fe2O3 0·30%; MgO 0·08%; CaO 1·65%; Na2O 0·15%; K2O 1·40%; H2O+ 11·22%; H2O− 6·16%; total 100·48%. A negligible amount of MgO indicates that both octahedral sheets of the chlorite structure are dioctahedral. Structural formula is given as (K0.58 Na0.09 Ca0.57)(Mg0.04 Fe3+0.07 Al12.05) (Al2.28 Si13.72) O40.00(OH)20.008.88H2O.A reflection at 30 Å with its higher order reflections and another reflection at 1·493 Å are observed. After heating at 300°C, a 27 Å phase has appeared, in which a single plane of water molecules was confirmed as the interlayer water of montmorillonite. The structures in air-dried state and in dehydrated steps were proved by comparing the calculated and observed F-values, and by Fourier synthesis. The DTA and TG curves and the i.r. absorption spectrum are reported in this paper.
Surface Area of Vermiculite with Nitrogen and Carbon Dioxide as Adsorbates
Authors: Thomas Josephus , Bohor Bruce F. 
Published: August 2006

AbstractSurface-area studies were made on several homoionic vermiculites with both nitrogen and carbon dioxide as adsorbates. These studies show that only very slight penetration occurs between individual vermiculite platelets. This is in contrast to an earlier investigation of montmorillonite where it was found that the degree of penetration between layers is quite high, particularly for carbon dioxide, and is governed by the size and charge of the interlayer cation. The inability of these adsorbates to penetrate substantially between vermiculite platelets is due primarily to this mineral’s high surface-charge density.The extent of penetration of nitrogen and carbon dioxide at the edges of vermiculite platelets, though slight, is influenced by the coordinated water retained within the sample at a given degassing temperature. Forces between layers are weakened with increasing water content, which permits slightly greater penetration by adsorbate gases. Thus, the surface area of vermiculite, as determined by gas adsorption, is larger than the calculated external surface area based upon particle size and shape considerations. In addition, “extra” surface is provided by the lifting and scrolling of terminal platelets. These morphological features are shown in scanning electron micrographs of a naturally occuring vermiculite.
Montmorillonite Deposits in Nevada
Authors: Papke Keith G. 
Published: August 2006

AbstractNevada has produced one-third million tons of montmorillonite clays; a major portion was natural adsorbent clay from the Ash Meadows district. Four properties, 3 with swelling and 1 with non-swelling montmorillonite, are currently producing.Detailed geologic and laboratory studies were made of thirty Nevada montmorillonite deposits. Pyroclastic and other volcanic rocks, mainly Miocene and Pliocene in age, were the host for most of these. The montmorillonite deposits are believed to have been formed in four ways: (1) eleven deposits by alteration of volcanic ash shortly after it settled in lacustrine basins; (2) two deposits by deposition of fine-grained clastic materials; (3) eleven deposits by hydrothermal alteration of a variety of rock types near structural channelways; and (4) six deposits by partial leaching and alteration of glassy, rhyolitic volcanic rocks by ground water.Montmorillonite is the predominant clay mineral in all the deposits except Ash Meadows, where saponite is present. Sodium is much more common as the exchangeable cation than calcium and/or magnesium. Kaolinite and illite are present in one-fifth of the samples; chlorite or mixed-layer material are rarely present. Quartz, cristobalite, feldspars, calcite, and gypsum are common impurities.The tests performed on the clay samples were: color; texture; slaking reaction; percentage swelling in water; plastic viscosity, yield point and gel strength of clay-water slurry; colloid content; and pH. Some montmorillonites formed by incomplete alteration of pyroclastic rocks can be wet separated to yield a light-colored, — 2μ fraction with superior viscosity and thixotropy.