Clay Science
Online ISSN : 2186-3555
Print ISSN : 0009-8574
ISSN-L : 0009-8574
Volume 26, Issue 3-4
Displaying 1-4 of 4 articles from this issue
Invited Review
  • Yoshiaki Fukushima
    2022 Volume 26 Issue 3-4 Pages 39-45
    Published: November 30, 2022
    Released on J-STAGE: December 01, 2022
    JOURNAL FREE ACCESS

    Studies on arrangement of silicate layers in aqueous suspensions from a viewpoint of liquids/solids bridging matters were reviewed. Results of X-ray diffraction, direct observation by using a scanning electron-assisted dielectric microscopy (SE-ADM), and analyses of small-angle neutron scattering coupling with rheological measurements (Rheo-SANS) of the aqueous suspensions-were indicated. Based on the results, the origin of the Thixotropic flow was discussed. From another viewpoint of clay minerals as organic/inorganic bridging matter, a development of organic polymer/clay minerals was reported. Properties of the hybrids were discussed associated with true nano-structured material. The microstructure of surfaces of Yohen Tenmoku bowl was introduced as an example of the true nano-structured material.

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Letter
  • Takafumi Aizawa, Munehiro Kubota, Takeo Ebina
    2022 Volume 26 Issue 3-4 Pages 47-52
    Published: November 30, 2022
    Released on J-STAGE: December 01, 2022
    Advance online publication: August 09, 2022
    JOURNAL FREE ACCESS

    In this study, the He gas permeability of films made of natural smectite and butenediol vinyl alcohol copolymers, which are polymers with high gas barrier properties, was measured in a wide range of compositions from 100% natural smectite to 100% polymer between 40°C and 160°C. The gas permeation behavior was discussed in terms of activation energy. Since butenediol vinyl alcohol copolymers form intra/intermolecular hydrogen bond networks, it was found that the activation energy of gas permeation is reduced by the addition of clay, which may be due to the suppression of the mobility of polymer molecules by clay. Moreover, the gas barrier deterioration was more suppressed with high temperature than with the polymer alone. The calculated gas permeability of the 25-µm coating layer at 160°C was less than 10 mL m−2 day−1 bar−1 in the polymer range of 10–40 wt%, indicating excellent gas barrier properties even at high temperatures.

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Papers
  • Ngon Ngon Gilbert Francois, Lassou Siamsia Maxime, Mbog Michel Bertran ...
    2022 Volume 26 Issue 3-4 Pages 53-64
    Published: November 30, 2022
    Released on J-STAGE: December 01, 2022
    JOURNAL FREE ACCESS

    This study focused on elaborating geochemical maps of clay materials in the Babouri-Figuil basin (North Cameroon) in order to evaluate the raw material for use in the manufacture of clinker. Particle size distribution, X-Ray diffraction, X-Ray Fluorescence spectrometry (XRF) and alumina-iron ratio (AR) were used in order to determine the quality of the raw material. Surf software and ArcGIS constituted the software used in elaborating the geochemical maps. The maps revealed two main types of sediments in the study area which include claystones (sandy clay and argillite) and fine limestones. The particles of claystones are essentially constituted of fine under 20 µm. Their bulk of mineralogical composition is constituted of kaolinite (22.4–25.8%), smectite (9.2–13.8%), calcite (10.3–12.1%), quartz (44.0–46.8%), feldspar (3.2–4.6%), which are the most predominant minerals; while chlorite (1.2–2.8%), hematite (1.7–2.3%) and goethite (1.7–2.3%) are accessories. These claystones have 21.13 to 58.31% of SiO2, 7.51 to 21.88% of Al2O3 and 4.61 to 12.98% of Fe2O3. Alkali and alkaline earth oxides (CaO, MgO, K2O and Na2O) have weak contents with the exception of CaO (0.68–8.38%) whose relative high content is linked to the presence of limestones in the field. All these properties show that these clays studied in the Babouri-Figuil basin are suitable raw materials for manufacturing of clinker. The extension of clays with good AR (1.3< AR<2.0) is 45 out of 69 blocks, which cover 65% of the study area. This justifies why cement factories exploit these clays.

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  • Hidetaka Miyahara, Yohey Hashimoto, Kazuko Mampuku, Masaya Suzuki
    2022 Volume 26 Issue 3-4 Pages 65-72
    Published: November 30, 2022
    Released on J-STAGE: December 01, 2022
    Advance online publication: August 17, 2022
    JOURNAL FREE ACCESS

    Enhancement of CO2 removal using adsorbent agents is a promising technique to reduce the atmospheric CO2 levels. The objectives of this study were to develop novel porous aluminum silicates with different Si/Al molar ratios and to investigate their properties for CO2 adsorption and recovery with the pressure swing adsorption (PSA) process. At a pressure less than 5 kPa, the amount of CO2 adsorption by the porous aluminum silicates at each pressure increased with decreasing the Si/Al molar ratios from 2.0 to 1.1. Adsorption of CO2 by the porous aluminum silicates is closely related to the number of ultra-micropores at a pressure less than 5 kPa and the specific surface area at a pressure greater than 8 kPa. At a CO2 partial pressure less than 18 kPa, Zeolite-13X has a greater CO2 recovery than any other porous aluminum silicates. Contrarily, the porous aluminum silicates have a greater CO2 recovery than Zeolite-13X at a CO2 partial pressure greater than 18 kPa. The efficient CO2 recovery by porous aluminum silicates at a pressure greater than 8 kPa requires a large number of pores with 1.3 to 2.9 nm in diameter and a large specific surface area.

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