Kaolinite

About: Kaolinite is a research topic. Over the lifetime, 8545 publications have been published within this topic receiving 224537 citations. The topic is also known as: myelin.

Fluorescence X-ray microscopy on hydrated tributyltin-clay mineral suspensions

Abstract: Using the scanning transmission X-ray microscope at ID21 beamline of the ESRF in fluorescence mode, we mapped tin at a bulk concentration of 1000 μg(Sn)/ml within hydrated tributyltin (TBT) - clay mineral (Kaolinite) dispersion with sub-300 nm spatial resolution. Using the L absorption edges of tin at 3929, 4156 and 4465 eV fluorescence radiation was excited in tin atoms with incident photon energies of 4 and 4.5 keV. When using 4 keV radiation, only tin fluorescence is excited. For 4.5 keV X rays, both the fluorescence of tin and calcium (which is present in the solid phase) can be measured. Methodologically, we were interested in assessing and proving the possibilities and limitations of fluorescence mapping using the L absorption edges of tin, where the fluorescence yield is significantly lower compared to other elements with their K edges in the same energy range. Scientifically, organotin-clay mineral interactions are of environmental concern because this factor influences significantly the distribution of toxic TBT in the aquatic system. On one hand, the half-life of TBT deposited to the sediment phase increases, and consequently the time of its bioavailability. On the other hand, the adsorption process is reversible, which means that contaminated sediments can act as a source of pollution. The adsorption and desorption effects can be studied directly with high spatial resolution and brought into connection to the surface properties of the clay mineral under study as well as to other experimental parameters, like pH or salinity.

ESEEM of industrial silica-bearing powders: reactivity of defects during wet processing in the ceramics production

Abstract: A study is undertaken to ascertain whether changes in the speciation of inorganic radicals are occurring during the ceramic industrial production that involves abundant silica powders as raw material. Industrial dusts were sampled in two ceramic firms, immediately after the wet mixing stage, performed with the aid of a relevant pressure. The dusts were then characterised by means of X-ray diffraction, analysis of the trace elements through chemical methods, granulometry, continuous-wave electron paramagnetic resonance (EPR) and pulsed electron spin echo envelope modulation (ESEEM) spectroscopies. The results of the characterisation point to a relevant change in the speciation of the two samples; namely, a prevailing contribution due to an inorganic radical different from that pertaining to pure quartz is pointed out. The combined interpretation of EPR and ESEEM data suggests the attribution of the main paramagnetic contribution to the A-centre in kaolinite, a constituent that is added to pure quartz at the initial stage of the ceramic production. In one of the two samples, a second weak EPR signal is attributed to the quartz’s hAl species. By taking into account the relative quantities of quartz and kaolinite mixed in the two samples, and the relative abundances of the two radical species, we propose that the partial or complete suppression of the hAl species in favour of the A-centre of kaolinite has occurred. Although this change is apparently fostered by the mixture between quartz and another radical-bearing raw material, kaolinite, the suppression of the hAl centre of quartz is ascribed to the role played by the pressure and the wet environment during the industrial mixing procedure. This suppression provides a net change of radical speciation associated with quartz, when this phase is in contact with workers’ respiratory system.

The Effect of Kaolinite Structure Changes on Its Transformation Temperature of Phases

Abstract: The relationship between kaolinite structure and the temperature of thermal transformation of phase was discussed in this paper through grinding and heating treatment. The results show that the structure of kaolinite is destroyed rapidly with mechanical grinding time, and the kaolinite structure collapses completely after 1 h grinding. The temperature of thermal transformation of phase of decreases with the destruction of kaolinite structure. This result has a great significance for the utilization of kaolinitic rocks in China coal measures.

Source and diagenesis of Middle Jurassic marine mudstones, Kopet-

Abstract: Middle Jurassic fluvio-deltaic and turbiditic mudstones of the Kashafrud Formation are important hydrocarbon sources in the gas-rich Kopet-Dagh Basin, northeastern Iran. Clay mineral assemblages are important for the interpretation of sediment provenance and for understanding burial diagenetic cementation in sandstones. The clay mineral assemblages in fluvio-deltaic and turbiditic mudrocks in two areas, Saleh-Abad and Senjedak, were investigated by X-ray diffraction analysis. A total of 28 bulk samples (half of which were taken from Saleh-Abad and the other half from Senjedak) were analysed and from 11 of these samples the <2 µm fraction was separated and analysed. The clay minerals identified are mostly kaolinite, illite, muscovite, chlorite, mixed -layer illite-chlorite, and very rarely smectite. Clay mineral assemblages result partly from variable det rital supply and partly from burial diagenesis. Detrital muscovite is more abundant at higher stratigraphic levels. Detrital smectite was rare; the lack of detectable illite -smectite mixed layer clays indicates that low smectite abundance is not the result of illitization. Vitrinite reflectance suggests burial to depths of only 2 –3 km. Burial diagenesis resulted in more chlorite and more ordered mixed -layer chlorite-illite at greater burial depths. The source area for the basin was a rapidly rising area th at included illitic shales, overlying crystalline basement of granite, and low -grade metamorphic rocks, which supplied muscovite and chlorite.

Method of modification of iron-containing surfaces of friction units

Abstract: FIELD: machine engineering.SUBSTANCE: friction surfaces are fed to the treatment zone of a pre-prepared process medium containing a hydrocarbon carrier and 0.01 to 0.15 wt % of the pre-crushed mixture of minerals shungite, kaolinite, talc, dolomite, carbon black, sulfur of a colloidal and surfactant (surfactant) with the following ratio of them in a mixture, wt %: shungite - 0.5…10, kaolinite - 0.1…30, talc - 0.1…25, dolomite - 2…20, gas black - 1…8, sulfur colloid - 0.1…10, surfactant - 2…5. The dispersion of particles of mineral components and surfactants is 0.1…10.0 mcm. In particular embodiments of the invention, the mentioned mixture of minerals uses an increased content of natural fullerenes in the shungite. In mentioned mixture of minerals, black and gas colloidal grease is used as antifriction components used as solid lubricants to reduce the degree of abrasion of kaolinite, talc and dolomite when modifying the contacting surfaces.EFFECT: increasing the efficiency and intensity of formation in the near-surface layers of the friction surfaces of a modified protective antifriction layer of increased wear resistance.3 cl, 1 tbl