bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of Clay Minerals by X-Ray Diffraction Analysis
Authors: Brindley George W. 
Published: August 2006

Abstract
Since X-ray diffraction patterns are directly related to crystal
structures. X-ray identification is, in principal, better suited to the
recognition of structural groups and structural varieties than of chemical
species.
Well-formed kaolin, mica, and chlorite structures give rise to
characteristic 7, 10 and 14Å spacings which are relatively easily
identified. Hydrated forms, such as hydrated halloysite
(d = 14Å) and montmorillonoids under normal
conditions (d= 14Å), are recognized either by
low-temperature dehydration giving characteristically diminished spacings,
or by the formation of organic complexes giving characteristically increased
spacings. This introduces at once the principle that X-ray identification
may, and generally does, entail the study of mineral modification by
suitable chemical and/or thermal treatment.
The main requirements in the X-ray technique are: (1) Ability to record
long spacings up to 2.5Å or even higher values; (2) well focused lines with
good resolution; (o) absence of background scattering and white radiation
anomalies. Of these, (1) and C) lie within the control of the investigator,
but (2) depends partly on the material.
The main difficulties of X-ray identification are: (1) The multiplicity
of lines when many components are present, and (2) poorly defined diagrams
arising from poor crystallinity and/or small size of crystals. The first can
be treated experimentally, but the second is inherent in the problem.
Simidification of X-ray diagrams is possible by sedimentation, acid
treatment and thermal treatment and by the use of orientated.specimens. Poor
quality powder diagrams (if not due to poor technique) are of interest in
themselves and may still give valuable information concerning the clay
minerals, more particularly when monomineralic or mainly monomineralic
fractions are used. Line profiles give valuable indications of randomly
displaced layers and of interstratified sequences.
The recognition of chemical species by X-rays is difficult but some
progress can be made if pure or nearly pure specimens are obtainable. The
recognition of di- and tri-octahedral minerals by the (060) spacing is well
known but the recognition of micas and chlorites in any greater detail is
difficult. A consideration of basal spacings and basal intensities may make
more specific identification possible.
Clay Technology in Ceramics
Authors: Henry Edward C. 
Published: August 2006

Abstract
Clays are used in the ceramics industries largely because of their
contribution to the moulding and drying properties of the wares being
produced; many clays, such as the flint clays, are used because of favorable
behavior during firing or because they produce favorable properties in fired
ware.
To assure the most effective use of a clay, the ceramic technologist
must meet problems of purification, aging, bacterial action, and the
improvement of the working properties of clays and bodies through additions
of non-plastic materials or chemicals. He deals with flocculation and
deflocculation, thixotropy, and related phenomena in casting slips. Control
of drying behavior is important. Finally, the ceramist is concerned with the
influence of the clay content of ceramic bodies on their behavior during
firing.
Clay Mineral Investigation of Sediments in the Northern Gulf of Mexico
Authors: Grim Ralph E. , Joitns William D. 
Published: August 2006

AbstractClay mineral studies of recent sediments from a diversity of environments in the vicinity of Rockport, Texas, have been made as part of American Petroleum Institute Project 51.The bulk of the argillaceous material in these sediments is a complex mixture of poorly crystallized three-layer clay minerals. Problems of the identification and nomenclature of the components of such mixtures are considered.Variations in areal distribution of the clay mineral constituents indicate progressive diagenesis in response to changing chemical environment. The gradual loss of montmorillonitic source material with the ultimate formation of poorly crystalline illitic and chloritic phases has been related to variations in environment. Environmental criteria based on clay mineral compositions are suggested.
Clay Mineral Content of Gulf Coast Outcrop Samples
Authors: Simons L. H. , Taggart M. S. 
Published: August 2006

AbstractClay samples were taken from formations outcropping between Corpus Christi and Uvalde, Texas, during the annual field trip of the Corpus Christi Geological Society in 1953. The geologic age of the formations sampled ranges from Quaternary to Upper Cretaceous. Both surface and near-surface samples were taken. The results of examination of these samples by use of x-ray diffraction and electron microscope techniques indicate marked differences in the relative proportions of montmorillonite, kaolinite, and illite. Comparison of surface and near-surface samples indicates the probable course of weathering.
The Solubility of Silica in Hydrogen Beidellite
Authors: Woodruff C. M. 
Published: August 2006

AbstractElectrodialyzed suspensions of clay minerals are viewed generally as insoluble silicates in which the exchange complex is saturated with hydrogen. An investigation of the relative activities of different exchangeable ions on beidellite clay brought to light the fact that a freshly prepared hydrogen clay containing a trace of the non-adsorbed chloride ion, when filtered, yielded a solution containing the chloride ion in association with silica rather than with hydrogen.The filtrate from the freshly prepared suspension was clear and had a pH value of 5.5. After standing 24 hours the filtrate became cloudy and the pH value dropped to 3.5 corresponding to the concentration of acid produced by the chlorides in association with hydrogen. Analysis of the clear filtrate revealed that the chlorides were associated with silica. The amount of soluble silica in the filtrate from the clay suspension was related directly to the amount of exchangeable hydrogen in the clay. No soluble silica was present in the filtrate from clay which had been neutralized with either potassium or calcium hydroxide.
An American Occurrence of Volkonskoite
Authors: McConnell Duncan 
Published: August 2006

AbstractChromium-bearing members of the montmorillonite group have been reported heretofore only for Russian localities, where they have been related genetically to serpentines. A green mineral which occurs in high-angle fissures in the Morrison formation (Upper Jurassic) near Thompsons, Utah, contains about 2 percent Cr2O3. Data were obtained by optical and electron microscopy, x-ray powder diffraction, and gravimetric and spectroscopic chemical methods. The ultimate source of the chromium remains an unresolved geochemical question, as do the sources of vanadium and uranium in the Morrison sandstone.
Distribution of Clay Minerals and Ion-Exchange Capacity in Some Sedimentary Materials
Authors: Hathaway John C. , Carroll Dorothy 
Published: August 2006

AbstractThe cation-exchange capacity of the clay fraction was determined in 67 samples of various types of sedimentary materials, and the clay minerals were identified from x-ray diffractometer patterns of oriented aggregates. The probable quantitative clay mineral composition was established for each sample assuming a comparable degree of crystallinity for the clay minerals in the sample. Agreement was poor between the ion-exchange capacities determined and those predicted from the clay mineral composition. The results suggest that the figure obtained for the ion-exchange capacity of a sample of sedimentary material may be misleading as a guide to the types of clay minerals present.The residual soils among the sedimentary materials examined had clay fractions with greater variation in ion-exchange capacity than did unconsolidated sediments generally of alluvial origin.
Thermogravimetric Analysis of Clay and Clay-Like Minerals
Authors: Mielenz Richard C. , Schieltz N. Cyril , King Myrle E. 
Published: August 2006

AbstractThe thermogravimetric method offers a new approach to the study of clay and clay-like minerals as well as other minerals and compounds that gain or lose weight upon heating. This method is complementary to differential thermal analysis, which records energy gains or losses upon heating. Thermogravimetric curves for clay and clay-like minerals are presented and correlated with curves obtained by the differential thermal method. The apparatus, procedures, limitations, and application of the method are described and illustrated.
Multifunctional Ionization as Illustrated by the Clay Minerals
Authors: Marshall C. E. 
Published: August 2006

AbstractThe electrochemical properties of clays are discussed under four rules which arise from considerations of the bonding energy of ions associated with charged surfaces. The mean free bonding energy of a cation associated with a negatively charged surface is determined by calculation from conventional potentiometric measurements with membrane electrodes.The first three rules are concerned with the effects of valency upon ionization. They arise directly from the method of calculating cationic mean free bonding energies, applicable to monofunctional surfaces as regards Rule 3, and to polyfunctional surfaces also as regards Rules 1 and 2.The fourth rule (Jarusov’s rule) deals with mixtures of cations on polyfunctional surfaces. It may be expressed verbally by stating that the cation with the higher mean free bonding energy preempts those positions on the surface which manifest greater mean free bonding energy.The incidence of each rule is examined, using data from studies of cationic activities in clay systems. The factors which cause deviations from these idealized rules are discussed. Graphical data are presented for Wyoming bentonite, Arizona bentonite (montmorillonite), and Putnam clay (montmorillonite group); illite, kaolinite and attapulgite.
Chemical Determination of Tetrahedral Ions in Nontronite and Montmorillonite
Authors: Osthaus B. B. 
Published: August 2006

AbstractSamples of nontronite and montmorillonite were digested with dilute hydrochloric acid for various periods of time. Chemical determinations of the acid-soluble ions were made for each period of digestion. Curves are presented showing the rates of solution of these minerals as decreasing exponential functions of time. A change in the slopes of the curves, as plotted on semilogarithmic paper against time on the linear scale, suggests different rates of solution for the ions in the tetrahedral and octahedral layers. The initial slope of the curves represents the simultaneous rates of solution of the octahedral and tetrahedral layers with the octahedral layer predominating. The second slope of the curves represents the rate of solution of the tetrahedral layer predominantly. Extrapolation of this slope to zero time is thought to give the percent of the tetrahedrally substituted ions within very close limits. Solubility curves of nontronite suggest the presence of both iron and aluminum in the tetrahedral layer. The solubility curves for Polkville montmorillonite indicate there is no substitution for silicon in the tetrahedral layer. Experimental values of tetrahedral substitution in nontronite check very closely with values postulated from the theoretical calculations obtained from the chemical analysis of the mineral.
Electron Microscopy of Clay Surfaces
Authors: Bates Thomas F. , Comer J. J. 
Published: August 2006

AbstractImprovements in replica techniques have made possible the high magnification study of textural characteristics and surface features of clay aggregrates found either in nature or in the laboratory. The most successful method of sample preparation involves pre-shadowing the specimen with platinum and backing this with a layer of carbon prior to removal of the clay with a suitable solvent.Data on orientation and packing of clay particles are readily obtained. The method is useful to investigate clays in which the characteristic morphology is easily affected by environmental conditions or by sample preparation for other methods of study.Replicas of kaolinite indicate that many of the pseudohexagonal plates seen in electron micrographs are cleavage fragments. Investigations of halloysite (4 H2O) using this technique prove that the tubes exist as such in the bulk clay. Striations on montmorillonite flakes that intersect at an angle of sixty degrees suggest a degree of morphological crystallinity that is apparently destroyed when the material is dispersed prior to study in the electron microscope. Replicas of dickite, attapulgite and weathered feldspar also show features that have not heretofore been seen in electron micrographs.
Structural Irregularities in Hydrous Magnesium Silicates
Authors: Bradley W. F. 
Published: August 2006

AbstractThe crystal structures of chrysotile, antigorite, attapulgite, sepiolite, vermiculite, and montmorillonite are discussed in the light of the degree to which they resemble chlorite.The proposal is advanced that the perfection of articulation between tetrahedrally and octahedrally coordinated layers is temperature-sensitive, and that the several crystallizations reflect the degree to which difficulty of articulation limits the growth of particular compositions.
DTA of Kaolinite and Montmorillonite Under Water Vapor Pressures up to Six Atmospheres
Authors: Stone Robert L. , Rowland Richards A. 
Published: August 2006

AbstractThermograms of kaolinite and montmorillonite were obtained at water-vapor pressures varying from approximately 0.0001 to 4,500 mm. of Hg with a variable pressure, dynamic gas, differential thermal analysis apparatus. The beginning of the kaolinite endotherm is shifted to a higher temperature with increasing water-vapor pressure. The sharp kaolinite exotherm is shifted to a lower temperature until at six atmospheres water-vapor pressure it makes a small broad peak at approximately 900° C. The dehydroxylation endotherm of montmorillonite is almost unaffected. The 900° C endotherm and the recrystallization exotherm are shifted to a lower temperature with increasing water-vapor pressure. The temperatures of the start of the endothermic peaks associated with exchange cations are shifted upward by increased gas (N2) pressure.
Reference Chlorite Characterization for Chlorite Identification in Soil Clays
Authors: Martin R. Torrence 
Published: August 2006

AbstractLiterature pertaining to differential thermal and X-ray diffraction of chlorite minerals is reviewed. Optical, DTA, and X-ray data for eleven chlorite samples of clinochlore, prochlorite, thuringite, corundophilite, and leuchtenbergite are given. The effect of particle size (105 to −1 μ) on DTA, X-ray diffraction, glycol retention, and cation exchange capacity are given for two thuringites, one clinochlore, and one prochlorite.Identification of chlorite by DTA in a soil clay containing a mixture of minerals is improbable at the present time except under very favorable circumstances. However, for relatively pure chlorite samples, variations in chemical composition are reflected in the differential thermal curves. The largest change in the thermogram is produced by ferric iron which lowers the peak temperature from 720° C to 610° C. Differences in thermal behavior between low and high ferric iron chlorite species are maintained for any given particle size. Chlorite thermograms obtained by different investigators show much greater variation than the differences in thermograms for other clay minerals determined on different equipment.X-ray diffraction can be used to positively identify chlorite in a soil clay, (a) by careful analysis of reflections at least as great as 14 Å, and (b) by the influence heat treatment (550° C for 30 minutes) has on the X-ray pattern. Heat treatment produces marked changes in the X-ray pattern of the finer particle size samples and the magnitude of the change effected is greater for high iron chlorites (thuringite) than for low iron chlorites (clinochlore and prochlorite). Olivine is not the recrystallization product for thuringite. The smallest size fractions show no tendency toward vermiculite or montmorillonoid.Cation exchange capacity for silt size chlorites varies from 4 to 32 m.e./100gm., and for −2 μ chlorite particles from 30 to 47 m.e./100gm. Cation exchange capacities for −2 μ and −1 μ chlorites are essentially the same.Ethylene glycol retention increases with decreasing particle size. Glycol retention for −2 μ chlorite samples varies from 25 to 40 mg, glycol/gm, clay. For −1 μ chlorite material, glycol retention is 2 to 4 times greater than for −2 μ material.
Water Sorption Properties of Homoionic Montmorillonite
Authors: White W. Arthur 
Published: August 2006

AbstractHomoionic samples of four montmorillonite clays, selected on the basis of the properties which control their economic uses, were prepared by treating with two normal neutral solutions of ammonium acetate, lithium, sodium, potassium, calcium, and magnesium chloride. Atterberg plastic and liquid limits, slopes of the liquid limit curves, and water sorption curves were determined. Among the results suggested, the following are particularly considered:1.The plastic state is reached when enough water is put into the system to fill all the pore space and to supply all the montmorillonite layers with water adequate for rigid layers plus a slight additional amount.2.The type of cation is not the only factor which controls the properties of montmorillonite.3.The structure of the lattice also appears to determine the properties of montmorillonite.
Peptization Resistance of Selected Samples of Kaolinitic, Montmorillonitic, and Illitic Clay Materials
Authors: Whitehouse U. Grant , Jeffrey Lela M. 
Published: August 2006

AbstractVariations in the peptization resistance of selected samples of clay mineralogical materials toward alkaline dispersing agents are discussed from a quantitative point of view.Clay samples, collected from South Carolina, Wyoming, Illinois, New Mexico, South Wales, Great Britain and Cornwall, England were subjected to the action of solutions of Calgon (“sodium hexametaphosphate”), ammonia, sodium hydroxide, sodium carbonate, sodium pyrophosphate, and “sodium lignosulfonate.” The resulting apparent dispersion, in each case, was expressed as a function of the employed concentration and chemical nature of the dispersing agent. Pipette analysis and Oden balance techniques at constant temperature were used to measure the degree of dispersion. All clay samples employed were identified as to type by X-ray diffraction, chemical analysis, thermal analysis, and electron microscopy.All samples examined exhibited a maximum in apparent dispersion (suspension stability) at a specific concentration of dispersing agent. Such maximum was followed by a sudden decrease in apparent dispersion, i.e., flocculation, at higher concentrations of dispersing agent. Concentrations of dispersing agent were varied in steps of one part per thousand. One hundred and twenty experimental runs were made on each type of material examined. Differences in the degree of apparent dispersion attained by use of different dispersing agents were expressed in terms of a threshold concentration which altered “equivalent diameter” one tenth of a phi unit. Among dispersing agents employed, “sodium lignosulfonate” was found to be least selective of clay mineral type in its peptizing action.An equation for the calculation of a “peptization resistance factor” is presented. Results obtained by application of this equation indicate that differences in the response of the same clay material to different alkaline dispersing agents may be attributed, in part, to differences in degree of peptization achieved by “threshold mechanisms” of peptization and by “adjustment mechanisms” along the peptization path. Such equation may have future value in the differentiation of marine and terrestrial clay deposits.
Ion Pair Activities in Bentonite Suspensions
Authors: Davis Lannes E. 
Published: August 2006

AbstractThe thermodynamic activities of ion pairs were measured electrometrically in a series of aqueous mixtures of monoionic bentonite and the corresponding chlorides. Ion exchange membranes and Ag-AgCl electrodes were used. The lyotropic order for the various cation species varied somewhat for two different preparations. The apparent relative escaping tendencies of the various cations did not correspond to that usually assumed on the basis of related phenomena: ion exchange selectivity, electromigration velocities, flocculation values or rates, etc.
Clay Minerals in Some Illinois Soils Developed from Loess and Till Under Grass Vegetation
Authors: Beavers A. H. , Johns W. D. , Grim R. E. , Odell R. T. 
Published: August 2006

AbstractClay mineral analyses were made of three groups of soil profiles — one developed from Peorian loess overlying Illinoian till — one associated with glacial till of Wisconsin age — one developed on deep to thin loess overlying Wisconsin till. These groups were investigated to determine the influence of parent material and intensity of weathering upon the soil profile development and clay mineral composition.Montmorillonite, illite, and chlorite are the dominant clay minerals in all the samples studied. In known loess samples, montmorillonite is invariably the most abundant clay mineral component. In the samples of unweathered till of Wisconsin age, illite and chlorite are the abundant clay minerals.
The Effect of Acid and Heat Treatment on Montmorillonoids
Authors: Mathers A. C. , Weed S. B. , Coleman N. T. 
Published: August 2006

AbstractH-montmorillonite, -beidellite, and -nontronite were found to change spontaneously into Al-clays. Rates of conversion of H- to Al-clay were slow at 0°C, but at temperatures of around 100°C, moist H-montmorillonite changed to Al-saturated montmorillonite within 24 hours. It appeared that Al-ions moved from lattice positions to exchange positions, with octahedral Al moving more rapidly than tetrahedral Al.Treatment of montmorillonoids with HCl solutions at 80°C resulted in the removal of large quantities of Fe, Mg, and Al. The residue after hot acid treatment appeared to be a mixture of essentially unaltered montmorillonoid and SiO2, rather than a new mineral.On heat treatment, H- and Al-montmorillonites became largely non-expanding of 300°C, and lost the bulk of the CEC which could be attributed to permanent lattice charge, H- and Al-nontronite and -beidellite, on the other hand, did not suffer irreversible dehydration and loss of CEC until heated to sufficiently high temperatures to cause the expulsion of lattice OH. Montmorillonites with largely octahedral charge had smaller CEC’s after heating to 500°C than did montmorillonites with appreciable tetrahedral charge.