Mixture Of Kaolin Research Articles

Geophagy in birds of Crater Mountain Wildlife Management Area, Papua New Guinea

AbstractNumerous New Guinea birds, mostly psittaciforms and columbiforms, have been recorded feeding on soil. This study documents geophagy in the Crater Mountain Wildlife Management Area (CMWMA) in the Eastern Highlands of Papua New Guinea. We present the first documented case of geophagy in the palm cockatoo Probosciger aterrimus and in up to 11 other species. Soil from the site where geophagy by palm cockatoos was recorded was highly weathered and acidic, with a mixture of kaolin, gibbsite, goethite and illite in the clay fraction. Analyses may support the hypothesis that soil is ingested to counterbalance the effects of toxic compounds in fruit. We suggest that the accessibility of the site (an exposed bank), rather than the nature of the soil itself, prompted its use by birds. At another site, a blue‐coloured soil on which cassowaries fed was rich in vivianite (an iron phosphate) and contained an iron‐rich smectite, and some kaolin and mica in the clay fraction. Why cassowaries feed on this particular soil is unclear, but they may obtain trace elements from it, or take advantage of its high iron or phosphorus content. Obtaining other elements, in particular calcium and sodium, may also be important. Alternatively, there may simply be an attraction to its blue colour, which also attracted the interest of local people and folklore. Birds were also reported to drink salt water within the CMWMA. Taken together, there may be quite different reasons for ingestion of minerals/soils among as many as 23 bird species from five families.

Effect of kaolin content on structure and functional properties of water-based coatings

The water-based coatings for paperboard were pigmented with a mixture of kaolin and ground calcium carbonate (GCC). The effects of kaolin content on the morphology and gloss of the coatings were determined. Kaolin particle orientation in the coatings was measured with X-ray diffraction (XRD) technique using peak ratio method, which determines the ratio of the integrated peak area intensities of the ( 3 ¯ 3 ¯ 1 ) and (0 0 1) reflections. The gloss values and the number of platy kaolin particles oriented parallel to coating surface increased with increasing kaolin content. Moreover, when measured in machine direction, gloss was higher and the orientation index lower compared to measurements in cross-direction. The laser profilometer measurements indicated that the differences in machine and cross-directions are related to the macroroughness of the surface. Novel method to study the structure of coating was utilized by exposing the reverse-side of the coating with cupriethylenediamine (CED) solution. Scanning electron microscopy (SEM) studies of the reverse-side of the coating illustrated decreasing coating porosity with increasing kaolin content. CED-dissolving was utilized also for preparation of transmission electron microscopy (TEM) samples. Concurrently the utilized characterization techniques complemented each other and provided information of the correlation between the functional properties and the structure of the coatings.

Rheological properties of starch and kaolin mixtures in water during and after heating

Gelatinization characteristics of the starch and kaolin mixtures were investigated with the Brabender viscograph at starch concentration of 40 g/l and different kaolin concentrations from 0 to 60 g/l. The properties of starch gelatinization were affected by the addition of kaolin. Above a kaolin concentration of 12 g/l had, an additional viscosity peak was seen at 73 °C. Further increase of kaolin concentration up to 60g/l led to an increase is the additional peak at 73 °C, while the value of maximum viscosity peak decreased. The rheological features of gelatinized starch and kaolin mixtures were also investigated. Dependence of shear stress on shear rate was obtained with the use of Haake RS 100 rheometer with Z 38 AL sensor. Shear rate was first increased from zero to 200 s −1 and then decreased from 200 s −1 to zero within 400 s period. Those measurements were obtained at the 20, 40, 60 and 70 °C for the mixtures containing 10 or 20 g/l of starch and for kaolin concentrations ranging from 0 to 15 g/l. The results showed the independence between final viscosity and kaolin concentration in the mixtures. Viscosity was affected only by the temperature of the measurment and the starch concentration (10 or 20 g/l). A mathematical model for the rheological behavior of gelatinized starch, was developed which contains the number and volume of macromolecule aggregates as well as the number of bonds between aggregates. According to this model, the bonds energy between the aggregates reached the value of 2–8 kJ/mol, which seemed to be close to the Van der Waals bonds energy.

Development of a Novel Design for Diesel Particulate Filter

A novel design for diesel particulate emission filter based on wall structure of pore channels of honeycomb filter is proposed. Our anticipation in this new design is that, if whiskers are coated on walls of the pore channels of honeycomb filter, the trapping efficiency of honeycomb filter will be improved and also the pressure drop will be substantially reduced. In present study, cordierite whiskers were coated on cordierite based honeycomb support (diameter 13 cm, and height 14.5 cm, 600 cells/inch2) by in-situ method. Whisker coating was carried out on walls of the pore channels of cordierite support from aqueous slurry containing a mixture of kaolin, talc, alumina and silica. Coating was performed by wash coat method. Firing was carried out at 1350∘C for 4 h under flowing air atmosphere. XRD measurements revealed us complete formation of cordierite phase. SEM analysis on the coating showed the formation of three-dimensional network of cordierite whiskers on cordierite support. In order to evaluate the particulates trapping efficiency of the newly developed honeycomb filter, smoke test was carried out with a 2L diesel engine for the both un-coated and coated cordierite honeycomb samples and the results were discussed with respect to their microstructures.

Laminar and Turbulent Transition of Fine-Grained Slurries

An experimental investigation of flow behavior of fine-grained highly concentrated slurries, i.e., water mixtures of kaolin and fly ash from a fluidic-type combustion chamber produced during the process of desulphurization, in horizontal straight pipes is presented. A pipe loop with hydraulically smooth stainless steel pipes was used to measure the slurry flow parameters. Kaolin slurry has time-independent, yield pseudo-plastic response for volume concentrations higher than about 6%. In contrast, fluidic fly ash-gypsum water mixture is time dependent and showed substantial decrease of flow resistance due to the effect of shearing during the initial period of pumping. An intensive shearing of concentrated fluidic fly ash-gypsum slurry results in a substantial reduction of the hydraulic gradient in the laminar region and in a marked shift of the laminar/turbulent transition point towards a lower velocity value. After shearing in a turbulent regime a reduction in the hydraulic gradient at the transition point reached about 50% of its original value. The transition from laminar to turbulent regime results in an abrupt increase of flow resistance. The flow patterns become fundamentally different for the two regimes. It was found that pressure fluctuation could well indicate the laminar/turbulent transition. The transition from laminar to turbulent flow is very important for accurate and efficient design and operation of dense slurry pipelining. The optimum operational condition is slightly above the laminar/turbulent transition point, where flow conditions are often very attractive from an economic point of view.

Kaolin modified with new resin–iron chelate as flame retardant system for polypropylene

AbstractPolypropylene's fire‐retardant properties can be improved by using modified kaolin. Modification was done by reaction of kaolin with a prepared resin–iron chelate. Polypropylene samples were loaded with different amounts of kaolin, modified kaolin, and their mixture. Ignition properties of the produced samples were evaluated using cone calorimeter, UL 94, and thermogravimetric analysis techniques. It was found that sample S2 loaded with a mixture of kaolin and modified kaolin had significantly reduced the smoke generation and had a heat release rate comparable to that with kaolin. It was also found that samples S4 and S5 loaded with modified kaolin burned out earlier than did the other samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3119–3125, 2004

Experimental Subsolidus Studies on Epidote Minerals

Despite the fact that epidote group minerals are very typical for metamorphism at very low pressure, e.g., in geothermal fields (Bird and Spieler 2004), the first successful synthesis of zoisite and epidotess was reported by Coes (1955) in a paper in the Journal of American Ceramic Society entitled “High pressure minerals.” Synthesis conditions were 1 GPa at 800°C; zoisite was obtained from a mixture of kaolin, SiO2, CaO, and CaCl2, whereas epidote was formed by adding FeCl2•H2O to the previous mixture. Once experimental facilities enabled pressures exceeding a few hundred MPa, zoisite and epidote minerals were easily obtained from a variety of starting materials, made of oxides, gels and glasses. Historically, early experimental studies on epidote focused on the formation at low pressure conditions, and then ventured into the simple system CaO-Al2O3-SiO2-H2O at conditions attainable by piston cylinder equipment (Newton and Kennedy 1963; Boettcher 1970) in which zoisite was found to have an extremely large temperature stability. Then, the role of Fe3+ was investigated systematically at pressures typical for the middle and lower continental crust (Holdaway 1972; Liou 1973). Epidote minerals in bulk compositions directly applicable to natural rocks were not investigated experimentally until the early 70’s (Liou et al. 1974; Apted and Liou 1983). Subsequent studies in the context of the very popular hydrous phase stabilities at subduction conditions in the 90’s extended the experimentally determined stability of epidotess in natural compositions to 3.5 GPa. With the relatively easy access to multi-anvil machines, the pressure stability of zoisite was defined (Poli and Schmidt 1998). The increasing number of experimental studies on epidote minerals reveals that the members of this group of ubiquitous rock forming minerals have …

Electrochemical behavior of the catalyst with kaolinite-bentonite substrate in water

Due to the fact that oxidation-reduction potential and rH2 value of every water are its crucial features, numerous efforts have been made to use electrochemical means for water preparation. In this paper, we report the results of electrochemical influence research of magnesium-aluminium silicate catalyst, in the form of ceramics made of kaolinite and bentonite clays, on the rH2, pH and EOR changes of the waters of particular characteristics in the wanted direction. Particularly, the possibility of changing "active water" characteristics was investigated. The composite made with micro alloyed aluminium exhibits a very negative stationary potential and its interaction with water results in water reduction. Addition of some active components to the mixture of kaolin and bentonite can provide clay mixtures, which after sintering at high temperatures produce very porous ceramics with microcrystalline and amorphous regions of stoichiometric and nonstoichiometric new oxides and some metallized surface (in our case-mainly with magnesium surplus). Nonstoichiometric oxide mixtures and metallized amorphous ceramics regions show high electrochemical and chemical activities in contact with water. This leads to redox potential changes and appearance of Mg2+ ions in the magnesium aluminium silicate-water system.

Features of SiAlON synthesis from kaolin

Under conditions of experimental–industrial synthesis of SiAlON from kaolin with the use of carbothermal reduction the fabrication of single-phase β′-SiAlON with z=2 is limited by a set of technological parameters: temperature and time of treatment, composition and volume of mixture. The introduction of iron additives in mixture is accompanied by the formation of iron silicides. The regions of melt of the highest iron silicides are the zones of SiAlON formation according to the VLS-mechanism. The powders synthesized in the temperature range of 1723–1873 K from the mixtures of kaolin, carbon, silicon carbide, and iron are the composite ones.

Volume change behaviour of clays: the influence of mineral composition, pore fluid composition and stress state

This paper analyses the influence of mineral composition, pore fluid composition and stress state on volume change behaviour of four different clayey soils: the Ponza bentonite, a commercial kaolin, the Bisaccia and the Marino clays. In order to investigate the role of the smectite content, also artificial bentonite–kaolin mixtures were tested. Oedometer tests were carried out on the materials “reconstituted”––according to Burland’s suggestions [Géotechnique XL (3) (1990) 329–378]––with distilled water, concentrated NaCl solutions and a non-polar fluid (cyclohexane). Some tests were carried out on dry materials. The results show that volume change behaviour of artificial mixtures and natural soils reconstituted with distilled water is strongly influenced by mineral composition and, in particular, by the smectite fraction. The influence on compression and swelling indices decreases with increasing axial stress, whereas, with respect to the coefficients of consolidation and swelling, it remains high in the whole considered stress range. An increase in pore solution concentration causes a reduction in compressibility. The effect increases with the smectite content, thus reducing the differences among the different soils. In particular, compressibility of the bentonite reconstituted with concentrated salt solutions becomes more similar to that of the commercial kaolin––which, in turn, is poorly influenced by pore solution concentration––than to that of the water-saturated bentonite. The dependence on the stress level of the effects of pore solution composition on both volume change indices and coefficients, is qualitatively similar to that of the effects of mineral composition. The materials prepared with cyclohexane behave similarly to the dry ones and they both are less compressible than the materials prepared with aqueous solutions. The coefficient of consolidation increases dramatically and swelling is negligible in the whole considered stress range. The changes seem to depend on an increase in resistance to interparticle sliding. In the case of the Ponza and Bisaccia clays, this hypothesis is supported also by the results of direct shear tests.

Synthesis of Al4SiC4

The conditions necessary for synthesizing Al4SiC4 from mixtures of aluminum, silicon, and carbon and kaolin, aluminum, and carbon, as starting materials, were examined in the present study. The standard Gibbs energy of formation for the thermodynamic reaction SiC(s) + Al4C3(s) = Al4SiC4(s) changed from positive to negative at 1106°C. SiC and Al4C3 formed as intermediate products when the mixture of aluminum, silicon, and carbon was heated in argon gas, and Al4SiC4 then formed by reaction of the SiC and Al4C3 at >1200°C. Al4C3, SiO2, Al2O3, SiC, and Al4O4C formed as intermediate products when the mixture of kaolin, aluminum, and carbon was heated under vacuum, and Al4SiC4 formed from a reaction of those intermediate products at >1600°C.

Involvement of spinal tyrosine kinase in inflammatory and N-methyl- d-aspartate-induced hyperalgesia in rats

Phosphorylation of a subunit of N-methyl- d-aspartate (NMDA) receptor by protein tyrosine kinase (PTK) Src or Trk is known to enhance its channel activity. We examined whether a spinally administered selective PTK inhibitor, lavendustin A, which has high affinity for Src and Trk tyrosine kinases, could influence the development and maintenance of inflammatory hyperalgesia or NMDA-induced hyperalgesia. Inflammation was induced by injection of a mixture of carrageenan and kaolin into the tail base of rats. In another group of rats, hyperalgesia was induced by intrathecal administration of NMDA. Intrathecal administration of lavendustin A (1.0 μg) or NMDA receptor antagonist, (+)-5-methyl-10,11-dihydro-5 H-dibenzo[ a, d]cycloheptane-5,10-iminemaleate, MK-801 (3.0 μg) before injection of a mixture of carrageenan and kaolin or after the development of inflammation inhibited carrageenan–kaolin-induced mechanical hyperalgesia. Intrathecal injection of 1.0 μg NMDA produced thermal and mechanical hyperalgesia. Co-administration of 1.0 μg lavendustin A with NMDA significantly reduced the duration of spontaneous pain behaviour and inhibited NMDA-induced hyperalgesia. Lavendustin A itself did not cause any sedation, motor impairment or analgesia. Our results suggest that inhibition of PTK could be therapeutically effective as an analgesic in some NMDA receptor-mediated hyperalgesic states.

Chemical Variability in Clays and Pottery from a Traditional Cooking Pot Production Village: Testing Assumptions in Pereruela*

This paper explores analytically the contemporary pottery‐making community of Pereruela (north‐west Spain) that produces cooking pots from a mixture of red clay and kaolin. Analyses by different techniques (XRF, NAA, XRD, SEM and petrography) showed an extremely high variability for cooking ware pottery produced in a single production centre, by the same technology and using local clays. The main source of chemical variation is related to the use of different red clays and the presence of non‐normally distributed inclusions of monazite. These two factors induce a high chemical variability, not only in the output of a single production centre, but even in the paste of a single pot, to an extent to which chemical compositions from one ‘workshop’, or even one ‘pot’, could be classified as having different provenances. The implications for the chemical characterization and for provenance studies of archaeological ceramics are addressed.

Role of B2O3in formation of mullite from kaolinite and α-Al2O3mixtures

The microstructure, phase constitution, and physical properties of mullite bodies prepared from α-Al2O3- kaolin mixtures with added B2O3 were investigated. Densification was found to be enhanced with small additions of B2O3. The results indicate that 0.5 wt-% B2O3 increases the content and growth rate of the mullite. It was found to be the optimum addition with respect to densification and resulting properties.

In situ synthesis of Al 2O 3–ZrO 2–SiC w ceramic matrix composites by carbothermal reduction of natural silicates

In situ formations of Al 2O 3+ZrO 2+SiC W ternary composite powders have been obtained by carbothermal reduction of a mixture of Sillimanite, Kaolin and Zircon using two different carbon sources. Products formed were mixtures of alumina and zirconia along with silicon carbide in the form of whiskers. The effects of composition of the reactants, the role of fineness of the starting precursors and the nature of the carbon source on the final product powder obtained are presented. XRD and SEM analyses indicate complete reaction of the precursors to yield Al 2O 3+ZrO 2+SiC W as product powders, with the SiC having whisker morphology. It is also seen that zirconia could be stabilised to some extent in the tetragonal form without any stabilising agent by tailoring the starting materials and their composition.

A new elastic viscoplastic model for time-dependent behaviour of normally and overconsolidated clays: theory and verification

This paper presents a new three-dimensional elastic viscoplastic (3D EVP) constitutive model for the time-dependent stress–strain behaviour of both normally consolidated and overconsolidated clays. There are two major new developments in the 3D EVP model: (i) incorporation of a nonlinear creep function with a limit for the creep volume strain under isotropic stressing conditions; (ii) adoption of a new loading surface function with a smooth shape on the π plane. Based on the "equivalent time" concept of Yin and Graham, the formulation of the new 3D EVP model is derived using the new nonlinear creep function and loading surface function. A new approach to determining all model parameters is presented. The 3D EVP model is calibrated using data from one conventional isotropic stress creep test and consolidated-undrained triaxial tests on soft Hong Kong marine deposits (HKMD). The model is verified by comparing model results with those from both normally and overconsolidated triaxial tests on HKMD and a mixture of kaolin and bentonite.Key words: creep, time-dependent, viscoplastic, equivalent time, stress–strain, constitutive model, verification, clay.

Determinação do espectro de reflectância de misturas de caulim através da Função de Kubelka-Munk

O caulim é um importante mineral industrial, cujo principal parâmetro é uma propriedade colorimétrica, que depende do espectro de reflectância da amostra, a alvura. A alvura por ser um parâmetro colorimétrico apresenta problemas na sua predição para mistura de caulins. Esse estudo descreve uma metodologia para determinação do espectro de reflectância de misturas de caulim.

Effect of the bonding ceramic material on the size of pores in porous ceramic materials

The results of studies on the effect of the grain size and amount of ceramic bonding materials (ceramic binder) on the size of pores in porous ceramic materials are presented. Electrocorundum and silicon carbide of various grain sizes were used as the grain material. Borosilicate glass was used as a ceramic binder for electrocorundum, whereas a mixture of kaolin with feldspars was used as that for silicon carbide. The sintering conditions were chosen so as the borosilicate glass was in a melted form, and the ceramic binder for silicon carbide only sintered during the sintering process. The studies showed that the mean pore size of the porous ceramic material decreases with an increase in the amount of the sintering ceramic binder and increases with that of the melting ceramic binder during the sintering process.

Hot Forging of Mullite‐Based Ceramics Prepared from Kaolin–Alumina

Mullite‐based ceramics prepared from a mixture of kaolin and alumina were plastically deformed in uniaxial compression tests at high strain rates (= 10−2–10−3 s−1) at 1450° and 1500°C. Deformation occurred with barreling in tests that used SiC platens coated with h‐BN. This study shows that more‐suitable lubricants and molds (platens) must be found, to reduce friction between the mullite‐based ceramics and molds. However, this hot‐working method can be used to give a fine, textured surface to mullite‐based ceramic substrates for polycrystalline silicon thin‐film solar cells.

Fouling performance in the filtration of water containing humic acid and/or kaolin with microporous membrane

Acceleration tests were done using the small-scale microporous membrane (MF) module to predict the increase in transmembrane pressure at the constant flow rate dead-end filtration in a pilot plant for treating the river water or dam water. The kaolin suspension, solution of humic acid and the mixture of kaolin and humic acid were used as feed water in the acceleration tests. The conventional equations of medium blocking filtration were applied to predict the pressure increase for both pilot plant tests and small-scale ones. The experimental results are summarized as follows: (1) The pilot plant tests: The time course of transmembrane pressure was expressed by the complete blocking filtration equation or the standard one when the unstable time at the beginning of operation was excluded. (2) The acceleration tests using small-scale membrane module:(a) No increase in transmembrane pressure was observed when the kaolin suspension and the bentonite one were used as feed water, (b) The increasing rate of transmembrane pressure was lowered by the addition of coagulant into the humic acid solution, (c) The humic acid had a great influence on the increasing rate of transmembrane pressure in the filtration of water containing kaolin or no kaolin and (d) Similar curves of filtration time vs. transmembrane pressure were obtained in the acceleration tests as were obtained in pilot plant tests.