Thermal Behavior and Decomposition of Intercalated Kaolinite

Magda Gábor1, Mária Tóth2, János Kristóf3 and Gábor Komáromi-Hiller1
1 Institute of Inorganic and Analytical Chemistry, L. Eötvös University, P.O. Box 32, H-1518 Budapest, Hungary
2 Research Laboratory of Geochemistry of the Hungarian Academy of Sciences, Budapest, Hungary
3 Department of Analytical Chemistry, University of Veszprém, H-8201 Veszprém, P.O. Box 158, Hungary

Abstract: Intercalation complexes of a Hungarian kaolinite were prepared with hydrazine and potassium acetate. The thermal behavior and decomposition of the kaolinite-potassium acetate complex was studied by simultaneous TA-EGA, XRD, and FTIR methods. The intercalation complex is stable up to 300°C, and decomposition takes place in two stages after melting of potassium acetate intercalated in the interlayer spaces. Dehydroxylation occurred, in the presence of a molten phase, at a lower temperature than for the pure kaolinite. FTIR studies revealed that there is a sequence of dehydroxylation for the various OH groups of intercalated kaolinite. The reaction mechanism was followed up to 1000°C via identification of the gaseous and solid decomposition products formed: H2O, CO2, CO, C3H6O, intercalated phases with basal spacings of 14.1 Å, 11.5 Å, and 8.5 Å as well as elemental carbon, K4H2(CO3)3 · 1.5H2O, K2CO3 · 1.5H2O, and KAlSiO4.

Key Words: Infrared spectroscopy • Intercalation • Kaolinite • Thermal Analysis • X-ray powder diffraction

Clays and Clay Minerals; April 1995 v. 43; no. 2; p. 223-228; DOI: 10.1346/CCMN.1995.0430209
© 1995, The Clay Minerals Society
Clay Minerals Society (www.clays.org)