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The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus >
No.23 (1976/12) >

Title :壷屋焼陶器の原料中の粘土鉱物について(農芸化学科)
Title alternative :Clay minerals in potter's earth for an Okinawan pottery, Tsuboya-yaki (Department of Agricultural Chemistry)
Authors :渡嘉敷, 義浩
Authors alternative :Tokashiki, Yoshihiro
Issue Date :1-Dec-1976
Abstract :沖縄産陶器の原料中特に壷屋焼陶器の原料として用いられる古我知, 喜瀬, 安富祖, 前兼久, 山田および喜名の6陶土について2,3の理化学性を調べ, そしてX線回折分析, 示差熱分析, 電子顕微鏡観察によって粘土およびシルト部分の鉱物組成を調べた。得られた結果は以下のように要約することができる。1.陶土の理化学性 いずれの陶土も土壌反応は強酸性を呈し, 粘土およびシルト部分の含量は素地土として用いられる古我知, 前兼久, 山田および喜名陶土の方が, 化粧土として用いられる喜瀬および安富祖陶土よりも高い傾向を示した。また, 他の陶土に比べ前兼久陶土は細砂部分の含量が, 喜名陶土は粘土部分の含量がそれぞれ著しく高いのが特徴である。喜瀬および安富祖陶土は粘土部分に含まれる非晶質成分および遊離酸化鉄の含量が著しく少なく, 古我知-a, 山田および喜名陶土は非晶質成分および遊離酸化鉄の含量が著しく多かった 2.粘土およびシルト部分の鉱物組成 古我知, 喜瀬, 安富祖, 山田および喜名陶土の粘土部分にはいずれもイライト, カオリナイト, 石英が含まれ, そして古我知, 喜瀬および安富祖陶土はイライトおよび石英が粘土部分の主体を占めた。また, 古我知-a, 山田および喜瀬陶土の粘土部分には, これらの鉱物の他にゲータイトが含まれた。一方これらの陶土のシルト部分には, 粘土部分と同様にいずれも石英, イライト, カオリナイトが含まれ, 安富祖, 山田および喜名陶土のシルト部分には石英がすこぶる優勢であった。前兼久陶土の粘土部分にはハロイサイト, カオリナイト, バーミキュライトが含まれ, ハロイサイトおよびカオリナイトが粘土部分の主体を占めた。また, シルト部分には石英, カオリナイトが含まれ, 石英が優勢であった。
Okinawan potteries are gaining popularity in these days and increasing buy of customers is causing them short in supply. The office of Okinawa prefecture is, in order to promote pottery industry, faced to argent need of exploitation of potter's earth besides privately owned ones that are used to be the main source of Okinawan potteries. The office, on the other hand, is required to make specifications of the potter's earth to keep the quality of the potteries. Very few, however, are scientifically studied on the potter's earth. The present study was to investigate physical, chemical and mineralogical properties of the potter's earth which were specifically used for Tsuboya-yaki, a kind of typical Okinawan potteries. Samples were collected from such six mines as Kogachi (-a and -b), Kise (-a and -b), Afuso, Maeganeku (-a and -b), Yamada, and Kina, all of those are located along the East China Sea side near the central part of Okinawa Island. The clay fractions were examined by means of selective dissolution, X-ray diffraction analysis, differential thermal analysis, and electron microscopy. Obtained results were as follows : i) All of the potter's earth sampled were strong acid as measured in suspension. ii) The contents of clay (<0.002mm) and silt (0.02-0.002mm) were higher (50-80%) in the samples from Kogachi, Yamada, and Kina which were being used for body of Tsuboya-yaki than those of Kise and Afuso (40-50%) which were for make-up of that pottery. The clay fraction was highest in Kina sample, but the fine sand fraction (0.2-0.02mm) was highest in Maeganeku samples. iii) The contents of amorphous materials and free iron oxides were negligible in the clay fractions of Kise-b and Afuso samples, but remarkably high in those of Kogachi-a, Yamada, and Kina samples. iv) The major crystalline minerals in the clay fractions were illite and quartz for Kogachi-a and -b, Kise-a and -b, and Afuso samples; halloisite and kaolinite for Maeganeku-a and -b samples. Kaolinite was also found in Kogachi-a and -b, Kise-a and -b, Afuso, Yamada, and Kina samples; vermiculite in Maeganeku-a and -b samples; and goethite in Kogachi-a, Yamada, and Kina samples as minor ones, respectively. v) In the silt fractions of Kogachi-a and -b, Kise-a and -b, Afuso, Yamada, and Kina samples found were quartz, illite and kaolinite, among which quartz was predominant in Afuso, Yamada, and Kina samples. Quartz was also the dominant crystalline mineral accompanied with a lesser amount of kaolinite in the silt fractions of Maeganeku.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4295
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.23 p.153 -164
Appears in Collections:No.23 (1976/12)

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