著者

中井 信 吉永 長則

出版者

日本粘土学会

雑誌

粘土科学 (ISSN:04706455)

巻号頁・発行日

vol.27, no.3, pp.153-161, 1987-09-05

被引用文献数

1

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Dissolution of various crystalline clay minerals and soil clays by hot acid oxalate treatment was assessed by the procedure of difference infrared absorption spectroscopy. The treatment dissolved lepidocrocite and vermiculite seriously, but partly hematite, goethite, kaolinite, halloysite (geological origin), montmorillonite and illite. Although halloysite from weathered pumice deposit may contain some amount of allophanic material, the difference infrared spectrum showed clearly the dissolution of a fair amount of the mineral. This specimen may be lower in "crystallinity" and, so, more susceptible to the treatment than that of geological origin. Relatively high value of weight loss for chlorite was ascribed to the dissolution of accessary minerals, such as vermiculite and halloysite. Severe dissolution of vermiculite may be due partly to that the mineral sample was tri-octahedral type. The difference infrared spectrum of limestone-derived soil clay showed the dissolution of the crystalline components, such as vermiculite and halloysite. On the other hand, the ash-derived soil clays showed almost complete dissolution of allophane and imogolite which were present as the principal components. All the above results point to that the acid oxalate treatment can never be selective for non and poorly crystalline clay materials, but dissolves the crystalline minerals considerably although the extent of the dissolution depends on the kind or type of minerals. This should be taken into account particularly when the soil clays containing much crystalline minerals are examined by the selective dissolution technique with acid oxalate.