DE- INTERCALATED KAOLIN ITES: THE NATURE OF CREATED DEFECTS AND EST IMATION OF STRUCTURAL CHARACTERIST ICS BY THE EXPERT SYSTEM OF PLAN(~ON AND ZACHARIE

ABSTRACT: Initial and de-intercalated (by washing with water from formamide molecules) kaolinite was investigated byX-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 Planqon & Zacharie (1990) decreases; (2) the degree of order of the structure as determined bythe 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 tothe 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 (Vas), 3550 (~'s) and 1650 (v~) cm 1. The results obtained are discussed inrelation to modern ideas on disorder models of kaolinite crystals. Two works published in 1989 (Bookin et al., 1989; Planqon et al., 1989) described a new concept for structural disorder of kaolinites. Bookin et al. (1989) analysed the previous models of structural disorder of kaolinites (Brindley & Robinson, 1946; Murray, 1954; Planqon & Tchoubar, 1977; Brindley, 1980) and concluded that these models are no