DE-INTERCALATED KAOLINITES - THE NATURE OF CREATED DEFECTS AND ESTIMATION OF STRUCTURAL CHARACTERISTICS BY THE EXPERT SYSTEM OF PLANCON AND ZACHARIE

Initial and de-intercalated (by washing with water from formamide molecules) kaolinite was investigated by X-ray and IR spectroscopic methods. As a result of de-intercalation by water washing, changes in structural characteristics and in some physical-chemical properties of kaolinites take place: (1) the content of low-defect phase (%ldp) evaluated by the expert system of Plancon & Zacharie (1990) decreases; (2) the degree of order of the structure as determined by the Hinckley index decreases; (3) the size of coherent scattering regions (CSR) determined by the method of fourth moments decrease; (4) the rate of repeated introduction of the formamide molecules to the interlayer increases. The cause of these changes are water molecules introduced into the kaolinite interlayer as a result of de-intercalation. These water molecules have IR absorption bands at 3646 (nu(as)), 3550 (nu(s)) and 1650 (nu(alpha)) cm 1. The results obtained are discussed in relation to modern ideas on disorder models of kaolinite crystals.