Kaolin analysis

Sokolowska, Z. and Sokolowski, S. (1999). Influence of humic acid on surface fractal dimension of kaolin analysis of mercury porosimetry and water vapour adsorption data. Geoderma, 88, 233-249. 

The PLS calibration set was built mixing in an agate mortar different amounts of Mancozeb standard with kaolin, a coadjuvant usually formulated in agrochemicals. Cluster analysis was employed for sample classification and to select the adequate PLS model acording with the characteristics of the sample matrix and the presence of other components. 

The table data show that the stress/strain properties of compositions are improved by additional dispersion (mixing). Ultrasonic analysis is sufficiently reliable and informative as a means of mixing quality assessment. The very small change of the characteristics for filled compositions (chalk + kaolin) can be due to the fact that these fillers are readily distributed in the matrix as they are. 

For the start-up of the RCC Unit DZ-40 was used. It was a combination of Ultrastable hydrogen Y, partially treated with rare earth, and ground to as fine a zeolite structure as commercially available and reasonable, and well dispersed in a specially developed silica-alumina cogel/Kaolin matrix. Table IV provides a typical analysis. 

The rate of disproportionation increases with decreasing pH and rising temperature and these conditions also favour oxide reduction. To achieve a reasonable rate of dissolution, one has to compromise on the pH. A pH of 3 is used in kaolin bleaching (Jepson, 1988), whereas in soil analysis the system is usually buffered with citrate and bicarbonate at ca. pH 7 (Mehra Jackson, 1960). Citrate also complexes the dissolved Fe " and prevents its precipitation as Fe" sulphide. For the dithionite/EDTA system, Rueda et al. (1992) found a maximum efficiency at pH 5-6 and an activation energy for goethite dissolution of 70 kj mol". They stressed the importance of adsorption of S2O4 on the surface to ensure reduction of Fe ". 

A wide variety of instrumental techniques, including X-ray diffraction, thermal analysis, electron microscopy, MAS-NMR and infrared spectroscopy, have been employed at different levels of complexity to investigate the effects of mechanochemical treatment on kaolin. Unfortunately, vibrational spectroscopy has only been used at a superficial level in the study of milled kaolin despite the considerable contribution that it has made to the understanding of the structure and reactivity of kaolin itself. 

Thermal analysis, and to a lesser extent infrared spectroscopy, has shown that grinding kaolin reduces the number of structural hydroxyls and increases the amount of sorbed water. However, the infrared studies have been restricted to... 

Periodically, these mixtures were centrifuged and an aliquot of the clay-free supemate taken for counting analysis. Two naturally-occurring clays were selected for the experiments one was labeled kaolin (for the mineral kaolinite) while the second was referred to as attapulgite (or polygorshite). Both were obtained from the Source Clay Mineral Repository (3) as standard clays representative of each class of clay and were used as received. Stable, colloidal suspensions of each were prepared by ultrasonically dispersing weighed quantities of each clay in triple-distilled water. 

The ash of true leather tanned with tannin consists essentially of calcium carbonate with traces of iron and of phosphates. Coloured leathers may contain metals from the mordants used (tin, copper, iron, chromium, aluminium) tin may also be introduced as stannous chloride used for bleaching. Small quantities of silicates (talc, kaolin) may be employed in the treatment of the leather. Finally, other mineral matters (barium, magnesium and lead salts and sodium chloride) may have been added as filling to increase the weight. Complete quantitative analysis of the ash is rarely necessary, but determination of its calcium content is sometimes required, this being made by the ordinary methods. 

Bio, G., Contado, C., Fagioli, F., Bollain Rodgiguez, M. H., and Dondi, F. (1995). Analysis of kaolin by sedimentation field-flow fractionation and electrothermal atomic absorption spectrometry detection. Chromatographia 41,715-721. 

This study focuses on a systematic analysis of the chemical activation of kaolin with HCl solutions under different conditions of time and temperature, with a complete discussion of the phenomena governing this process and a wide characterization of the solids obtained. Such a systematic study lacks in the literature and the interest in looking for new applications of natural clays justifies it. By this reason, we have carried out the acid activation of the metakaolins obtained by calcination of a kaolin between 600-900°C and a complete study of the solids prepared, where the porous properties of the prepared materials receive special attention, due to the high importance that these properties have over the industrial applications of the final solids. 

Sadik F, Fincher JH, Hartman CW. X-Ray diffraction analysis for identification of kaolin NF and bentonite USP. / Pharm Sci 1971 60 916-918. 

Kinetics. The kinetics of the reactions of bentonite 2 and kaolin 2 clays with standard synthetic waste solution were studied at three different temperatures 50°, 75°, and 100°C. The extent of the kaolin reaction was measured by determining (using thermal analysis) the amount of hydroxyl water associated with the unreacted kaolin in the solid product. The amount of unreacted bentonite was estimated by measuring the area of the endotherm attributed to loss of hydroxyl water from the bentonite. Reaction rate curves for the kaolin clay-waste reaction and bentonite clay-waste reaction at the above temperatures are shown in Figures 1 and 2, respectively. The great effect of temperature on the rate of reaction is apparent from these curves. It should be pointed out that there was an excess of clay in these experiments so that the maximum amount of clay reacted could be only 80%. Since the standard waste solution contains only 3.6M NaOH, it is expected that higher concentrations of hydroxide will increase the reaction rate. 

A number of FCC catalysts was used in the present study. For comparison of the effects of quinoline and phenanthrene additions to the n-hexadecane feedstock a model catalyst of composition, zeolite US-Y (30%), silica binder (25%), Kaolin (25%) and ps do Boehmite matrix (20%) was used. Quinoline and phenanthrene additions to the n-hexadecane amounted to 1% and 10%. The catalysts used to assess the effect of composition on product yields varied from a basic matrix material through a variety of zeolitic catalysts containing 20% zeolite and 15% silica binder, the remainder being clay, to a pure zeolite catalyst. Data for all the catalysts used are presented in Table 1. In addition for the C NMR analysis a sample of coked refinery catalyst obtained from a unit processing heavy feedstock was obtained. The coke level on this catalyst was 0.9% and 30g. of this catalyst was demineralised by standard HF treatment to produce a 250 mg sample of coke concentrate containing 65% carbon. 

Significant TS applications have been described by Butteridge et al., Bellchamber et al., and Shimada, " and one example is included here. Thermo-sonimetry has been applied to study the dehydroxy-lation behavior of kaolin, which show two regions of acoustic activity. The low temperature region corresponds to dehydroxylation and the high temperature region corresponds to recrystalization as metakaolinite. The relevant temperature regions of acoustic activity are defined by the coupled DTA analysis. 

In a second set of experiments, -74 pm size kaolin particles were leached with hot alkaline solutions to study the conversion of kaolinite to various sodium hydroaluminosilicate compounds (Table III) under different leaching conditions. In each experiment, 15 g. of kaolin was leached with 120 ml. of alkaline solution. The solid reaction product was recovered by filtration, washed with water, dried in an oven at 95 C, and analyzed by XRD. Although this method of analysis identified the minerals present, it could provide only an approximate indication of the relative proportions of the various minerals present. The amount of quartz was particularly difficult to assess because the method of detection was very sensitive to this mineral. Therefore, the results are reported only in terms of major, minor, and trace quantities present in the product as indicated by XRD (Table IV). Because the small amount of titania in the kaolin was apparently not affected by even the most rigorous leaching conditions, the product always contained a trace of this material and no further mention seems necessary. 

The clay minerals used in this study were kaolinite (AI281205(OH) ), illite (Kj A1jSi2+ (OH)2), and montmorillonite which was approximately 1/2 (Ca, Na)Q (Al, Mg, Fe) (Si, ADqO q (OH). n H2O. The clays were natural samples purchased from Ward s Natural Science Establishment, Inc. The kaolinite sample was obtained from a kaolin deposit in Georgia. X-ray diffraction (XRD) patterns on this material showed peaks only for kaolinite, and scanning electron micro-scope-energy dispersive x-ray (SEM-EDX) analysis yielded peaks for Al, Si, and minor amounts of Ti. The illite was a green shale from New York which Ward s listed as 85% illite. XRD patterns of this... 

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