Properties of a Ball Clay from Thailand-Comparison with the Clay from Germany for Pencil Leads.

DOI
  • HAYASHI Tsuyoshi
    Department of Environmental and Material Engineering, Teikyo University of Science and Technology
  • OTSUKA Nozomu
    Department of Environmental and Material Engineering, Teikyo University of Science and Technology
  • HASEGAWA Takashi
    Department of Research and Developement, Tombow Pencil Co., Ltd.
  • KOUNO Haruhito
    Department of Research and Developement, Tombow Pencil Co., Ltd.
  • KAZUNO Akihisa
    Department of Research and Developement, Tombow Pencil Co., Ltd.

Bibliographic Information

Other Title
  • タイ国産ボールクレーの性質　　鉛筆用ドイツ産粘土との比較

Description

The properties of a ball clay from Lansaka, Thailand, were compared with those of Klingenberg clay from Germany, which is used in manufacturing pencil leads due to its high plasticity. The clay fraction under 2μm in size in Klingenberg clay is mainly composed of kaolinite with a small amount of illite, and has a mean particle size of 0.4μm and a specific surface area of approximately 90m2/g. This clay is also characterized by a thermal property that the metastable transition period, from the temperature at which mullite begins to form to the temperature at which its growth stops, is long during heating. Lansaka ball clay resembles Klingenberg clay in some properties; both clays are composed of disordered kaolinite with fine particle size and are black due to the presence of carbonaceous organic substances. Furthermore, round grains with size on the micrometer order are commonly present in coarse fractions, presumably resulting from the disintegration during transport processes of the source rocks in rivers where fedspar is finely ground. On the other hand, the clay particles of Lansaka clay have a wider particle size distribution than those of Klingenberg clay because of the presence of a relatively large amount of illite, which results in a narrow metastable transition period during heating. Good moldability of pencil leads during the trial preparation was achieved by using Lansaka clay fractions under 10μm in size, which have a mean particle size of 1.7μm and a specific surface area of 27.1m2/g. The resulting pencil lead provided smoothness in writing with blackness of HB grade, although its bending strength was rather low because its firing temperature was above the optimum range.

Journal

Keywords

Details 詳細情報について

  • CRID
    1390001204111073280
  • NII Article ID
    130004307686
  • DOI
    10.11362/jcssjnendokagaku1961.40.90
  • ISSN
    21863563
    04706455
  • Text Lang
    ja
  • Data Source
    • JaLC
    • CiNii Articles
  • Abstract License Flag
    Disallowed

Report a problem

Back to top