EQUILIBRIUM BOUNDARY BETWEEN KAOLINITE AND PYROPHYLLITE

• Published in: Clay Science Vol. 8; no. 5; pp. 297 - 308
• Main Authors: MATSUDA, TOSHIHIKO, KUROSAKI, MAKOTO, HENMI, KITINOSUKE
• Format: Journal Article
• Language: English
• Published: Tokyo The Clay Science Society of Japan 1992; Clay Science Society of Japan
• Subjects: Earth sciences; Earth, ocean, space; Equilibrium boundary; Exact sciences and technology; Hydrothermal experiments; Kaolinite; Mineralogy; Pyrophyllite; Silicates; experimental studies; major elements; pyrophyllite; kaolinite; phase equilibria; clay minerals; sheet silicates; P-T conditions; hydrothermal conditions; X-ray diffraction analysis; chemical reactions
• ISSN: 0009-8574; 2186-3555
• DOI: 10.11362/jcssjclayscience1960.8.297

Hydrothermal experiments have been carried out to find the equilibrium conditions for the reactions: 2kaolinite=pyrophyllite+2diaspore+2water (1) kaolinite+2quartz=pyrophyllite+water (2) As starting materials, a natural mixture of kaolinite-pyrophyllite-boehmite was used for the experiments. Determination of reaction direction was based upon X-ray diffraction patterns. It has been confirmed that the equilibrium curve for the reaction (1) passes through the points 325 ± 10°C at 1kb and 330 ± 10°C at 2kb, and the curve for the reaction (2) passes through 250 ± 10°C at 1kb and 260 ± 10°C at 2kb. The present temperatures for the reaction (2) are lower than any other one reported so far.