This work describes the separation of alunite from natural alunitic kaolins by applying a selective flocculation procedure. In order to determine the most efficient separating procedure preliminary experiments were performed with artificial mixtures of alunite and kaolin. The same procedure was then applied to natural alunitic kaolin which enabled the preparation of kaolin of considerable purity.

The effect of heat treatment on surface area, pore volume, pore size distribution, physical and chemical structure up to 700°C have been studied on samples of naturally occurring chrysotile minerals from California and Quebec. Techniques used included thermogravimetric analysis, low-temperature nitrogen adsorption, electron microscopy, X-ray powder and electron diffraction. The materials behaved similarly on heating to 100°C showing a 0.5% weight loss attributable to desorption of physisorbed water. At 500°C, Quebec samples retained the chrysotile crystal structure while Californian samples were X-ray amorphous. Forsterite was formed by dehydration of both chrysotiles at 700°C; the greater stability of the Quebec samples to this process is explained by the presence of brucite as an impurity which enters into stray solid-solid interactions with the chrysotile.

This Article is a follow-up to a recent Gazette Article about a probabilistic betting game studied by Abdin et al. [1]. We examine the speed of convergence of the probability needed to investigate this game by giving concrete examples, using the large deviation, which is a valuable tool for estimating probabilities of repeated trials (see [2], [3, Chapter 6], [4, Section 5.11]). Moreover, to get a deep understanding of the game, we study fairness when it is repeated infinite times. Let us call it fairness in the sense of infinity, whose exact definition will be given in the final section.

The adsorption mechanism of iso-propylammonium (PAH+), the cationic component of Roundup, by various homoionic montmorillonites and the structures of the associations obtained in the interlayer space were investigated, using infrared, X-ray, and carbon analysis methods. Adsorption from aqueous and ethanol solutions of Roundup was studied. The infrared spectra were compared with those obtained by the treatment of montmorillonites with ethanol and CCl4 solutions of the free iso-propylamine (PA). The adsorption of PA from ethanol gives rise to protonation of the amine. PA sorbed from CCl4 solution forms an ammonium-amine association. Adsorption of PAH+ from alcohol solution of Roundup occurs by the mechanism of cation exchange. With transition metal exchangeable cations, PAH+ is sorbed in excess, forming hydrogen bonds between NH3+ groups and hydroxyls resulting from dissociation of water molecules. The process of adsorption of PAH+ from aqueous solutions of Roundup depends on the concentration of the solution. If montmorillonite is reacted with 0.5% solution of Roundup, PAH+ is adsorbed by exchanging metal cations and the adsorption capacity of the clay does not exceed the c.e.c. If the montmorillonite is reacted with 5.0% solution of Roundup, the PAH+ exchanges protons originating from the hydrolysis of the interlayer water. Protons which are transferred from the interlayer space to the water solution are accepted by the anion component of Roundup. The amounts of PAH+ adsorbed from concentrated Roundup solutions are much higher than the cation exchange capacity of montmorillonite. Hydrogen bonds are formed between the ammonium and water or hydroxyl groups on the interlayer space. With the trivalent exchange ions Al and Fe, which tend to polymerize in the interlayer space, excess sorption gives rise to hydrogen bonding of NH3+ to oxygen of the polymer.

Infrared absorption spectra show important changes in the positions and form of the absorption bands of a film of attapulgite after it has been pumped out. An attempt to differentiate among some of the multiple frequencies due to OH groups is based on the information obtained from dehydration and deuteration experiments. The 1198 cm−1 shoulder, characteristic of attapulgite, is assigned to a Si-O vibration. When attapulgite is refluxed with 5N HCl for 5 hr the octahedral layer is dissolved. The acid attack causes the disappearance of the Si-O-Si absorption bands from attapulgite giving rise to a characteristic vibration at 1090 cm−1, as well as another absorption at 960 cm−1. The latter indicates the presence of silanol groups.

Abnormal scatterings of X-rays take place between Bragg spots. Their study in hydrated Mg- and Ni-vermiculites shows that they appear in reciprocal space in the form of modulated lines, elongated along the Z* axis. These scatterings demonstrate a two-dimensional organization of the compensating cations and of the water molecules in the interlamellar layer. In such ordered domains, the cations are situated at the nodes of a biperiodic centered lattice with parameters 3a,b.

The distribution of compensating cations must conform with the charge distribution which they neutralize; it can therefore be concluded that the distribution of effective negative charges (tetrahedral negative charges less positive octahedral charges) is also at least partially ordered.

Sodium-saturated montmorillonite was used to prepare aqueous suspensions of varying concentration between 0.06% and 3.0%. Compacted columns of glass beads and carborundum constituted the porous media. The system was maintained under saturated flow conditions at hydraulic gradients of 2 and 4. In order to study the relationship of clay properties to those of the porous media, the zeta potential of both suspension and media was determined. A mathematical model of the system was developed that would predict the deposition of clay at various depths in the columns, given concentration and flow rate of the suspensions. In order to test this model, a procedure was developed for tagging the clay with 46Sc, sampling the columns, and determining the amount of deposition using a single-channel gamma-ray spectrometer. Using an activity level of 0.15 microcurie per liter of a 1% suspension it was possible to detect reliably 10 mg of clay in a 40 g sample of the porous media. The results indicate two mechanisms operating in the process of removal of the clay from suspension. One of these, interstitial straining, operates at the surface of the porous media column; while the second, a combination of diffusion and gravitational settling, operates below the surface.

The results of this research have potential applications in the solution of engineering problems relating to water resources conservation such as reservoir seepage control, infiltration of sediment-laden water into the soil, and ground water recharge. Also, the results may be important for answering questions concerning pollutant movement into the water supply through porous strata. All the above are examples in which a colloidal suspension is moving into or through porous media; therefore, an improved understanding of the principles of flow of colloidal suspensions in porous media can contribute to the solution of these engineering problems.

X-ray diffraction patterns of garnierites indicate that most samples resemble serpentine-group minerals or a talc-like mineral, or a mixture of these forms, and give respectively 7 Å and 10 Å basal reflections. From a survey of some 40 garnierites, four of predominantly serpentine type and seven of predominantly talc-like type were selected for detailed study. The talc-like garnierites exhibit little variation of the 10 Å basal spacing with low-temperature heating or with immersion in liquids, though some may contain a small proportion of expandable layers. Chemical analyses show considerable deviations of octahedral/tetrahedral cation ratios from the values 3/2 and 3/4 for normal serpentine and talc minerals, and may be interpreted in terms of mixed 1:1 and 2:1 layer types, either as separate phases and/or as interstratifications, or as defect structures of various kinds. The H2O + contents of the talc-like forms of garnierite are considerably greater than that of normal talc and point to a mineral of composition 3(Mg, Ni)O·4SiO2. 2H2O or [(Mg, Ni)3Si4O10(OH)2]H2O—a talc mono-hydrate formula. The green color of garnierites is related to the NiO weight per cent and a color index is derived based on the Munsell color charts.

A thermodynamic study has been made of the ion exchange equilibria of the n-alkylammonium ions in sodium montmorillonite. Exchange isotherms of ammonium, methylammonium, ethylammonium, propylammonium and butylammonium with sodium montmorillonite were determined at 4°, 25° and 55°C. From these data the changes in free energy, enthalpy and entropy for the exchange reactions were calculated. In the temperature region used in this work, no enthalpy change was observed. Thus the exchange was only controlled by entropy effects. The thermodynamic excess functions were calculated from the surface activity coefficients. The affinity of the organic ions for the clay increases with chain length. It is shown that this increase can not be ascribed to van der Waals forces, but must be due to the combined effect of variations in electrostatic interactions with the clay lattice and of the hydration state.

An orthochlorite (sheridanite) was heated to 610°C to dehydroxylate the hydroxide sheet and to oxidize ferrous iron. The heated sample was shaken for 20 min in a mixed solution of 0·2 N HCl and 0·2 N NaCl to dissolve the dehydroxylated hydroxide sheet. X-ray diffraction, thermal, infrared absorption and chemical analyses showed that the resulting product was similar to Kenya vermiculite. The procedure shows promise for the individual determination of the composition of the hydroxide sheet and of the mica layer in the chlorite structure. The experiments indicate that the hydroxide sheet in orthochlorites must be structurally disturbed before it can be selectively removed. In nature, structural disorganization of the hydroxide sheet of chlorite by dehydroxylation and oxidation of ferrous iron might occur during meta-morphic processes, and chlorite to vermiculite transformation could take place during subsequent acid weathering. In pedogenic weathering conditions it is likely that oxidation of ferrous iron plays a major role in initiation of the structural disorder required for the selective removal of the hydroxide sheet in the weathering of chlorite to vermiculite.

Silica-intercalated hectorite with an 001 spacing of 12.6 Å and a N2 BET surface area of 220 m2/ g was prepared by hydrolysis and oxidation at 500°C of hectorite containing a silicon acetylacetonate complex. The intercalate swelled to higher spacings upon adsorption of water, glycerol, and pyridine, but the silica was not expelled when the interlayers swelled and contracted in successive adsorption/desorption cycles. The surface area measured by isobutane adsorption agrees with the N2BET surface area, suggesting that the interlayers are available for adsorption of aliphatic hydrocarbons. The intercalated silica did not inhibit the ability of the interlayers to enter into cation-exchange reactions, as judged from Cu2+-binding experiments. Infrared studies of NH3-, pyridine-, and NO2-adsorption indicate the presence of Bronsted acidity and the absence of Lewis acidity in the interlayer regions.

Recent sediments of the Niger delta contain the detrital clay minerals kaolinite, mont-morillonite and a small amount of illite. The montmorillonite content increases with water depth and distance from the shore, and the results of laboratory experiments on natural Niger delta clay support the assumption that this is due to differential floc-culation and sedimentation.

The easterly Guinea Current, transporting montmorillonite-rich floccules in suspension, may cause an increase in the montmorillonite content of the clays in the ©cistern part of the delta.

Mineralized faecal pellets are present in most marine sediment samples. Chamosite occurs authigenically in coastal water shallower than 35 fathoms, as brown and dark-green pellets. Green pellets, composed of highly expandable, montmorillonite-type glauconite, are particularly common around the 100 fathom isobath. Both chamosite and glauconite have a high magnesium content, which seems to be usual during their early stages of formation.

The formation of chamosite and glauconite is governed by redox potential and the availability of iron. If no reduction takes place, the pellets remain grey and their composition is similar to that of the clay matrix. Grey pellets are less restricted to a particular depth than are the chamosite and glauconite pellets, but distinct maxima occur around the 250 fathom isobath.

Beginning with Soliloquy I for solo violin in 1998, the author has been engaged in creating a series of highly virtuosic solo pieces for various instruments. Each piece presents a different character, yet all are framed by a single protagonist who narrates in different languages.

This article focuses particularly on analyses of Soliloquies II, VI, VII, VIII and IX, but also offers a discussion of the genesis of and processes involved in the whole cycle, which now embraces instruments from every section of the orchestra; the most recent, Soliloquy IX, for solo trumpet, was written in 2022. The suitability of the title Soliloquy is also considered; this article in turn could itself be considered a soliloquy.

A smectite rich in ferrous iron and low in aluminum occurs abundantly in the Red Sea Geothermal Deposits, and appear to be forming at present.

Chemical analyses and Mössbauer spectra indicate the mineral is intermediate in composition between nontronite and the as yet undescribed trioctahedral ferrous iron end member.

The sorption of water, at 490°C and ca. 23–24 torr, on clay mineral surfaces has been studied using thermogravimetry and infrared absorption spectroscopy. Results from a series of synthetic hectorites, with and without lattice fluoride (see Granquist and Pollack, 1960), point to the presence of F− in the clay lattice as an important condition for the sorption. Similar studies on natural hectorite and montmorillonite, synthetic interstratified montmorillonite/mica with and without fluoride, and Al2F6 support this interpretation of the role of the F− ion and show that dioctahedral 2:1 clays sorb more water at 490°C than do trioctahedral 2:1 clays. The infrared spectra demonstrate that the sorbed water is for the most part hydrogen-bonded to the surface.

Oxidation of acetaldehyde molecules adsorbed on Na- and Mg-Wyoming montmorillonite at room temperature (20-25°C) and in N2 atmosphere has been studied by I.R. spectroscopy, A comparison between clay-acetic acid complex and that prepared from acetaldehyde is given. The influence of the nature of the saturating cation as well as the clay pretreatment on this oxidation process are discussed and reaction pathways are proposed. Acetic acid directly adsorbed on the clay surface is almost removed at 110°C, while that produced from the oxidation of the adsorbed acetaldehyde appears to be strongly held. Within a temperature range 180-230°C, the fixed acetic acid molecules dissociate to acetate form; then occurs an interaction of the acetate and the residual acid with the lattice OH of the clay at 200–300°C. This interaction involves the loss of the structural OH and deposition of carbon on the clay surfaces. The thermal decomposition of the residual complex is almost completed at 500–600°C