The Effect of Mechanical Treatment on the Crystal Structure and Thermal Behavior of Kaolinite

Éva Kristóf1, A. Zoltán Juhász1 and István Vassányi2
1 Department of Silicate Chemistry and Technology, University of Veszprém P.O. Box 158, H-8201 Veszprém, Hungary
2 Department of Mineralogy, University of Veszprém, P.O. Box 158 H-8201 Veszpræm, Hungary

Abstract: The destruction of the crystal structure of kaolinite caused by mechanical forces was investigated by X-ray diffraction, thermal analysis, infrared spectroscopy, and specific surface area determination. Attention was also directed to the change of thermal reactions of milled kaolinite. Grinding experiments for 5 min, 10 min, and 1, 2, 4, 6, and 10 h were carried out in an AGO I planetary mill. After 1 h of grinding, the crystalline order of kaolin is destroyed; but the amorphization continues in the course of prolonged grinding. Grinding for 1 h produces a favorable state for forming mullite-type crystals after heating even at 1000°C.

Key Words: Amorphization • Crystal structure • Grinding • Kaolinite • Mechanochemistry • Thermal behavior

Clays and Clay Minerals; October 1993 v. 41; no. 5; p. 608-612; DOI: 10.1346/CCMN.1993.0410511
© 1993, The Clay Minerals Society
Clay Minerals Society (www.clays.org)