Thermal Behavior and Decomposition of Intercalated Kaolinite

Abstract

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: H 2 O, CO 2 , CO, C 3 H 6 O, intercalated phases with basal spacings of 14.1 Å, 11.5 Å, and 8.5 Å as well as elemental carbon, K 4 H 2 (CO 3 ) 3 · 1.5H 2 O, K 2 CO 3 · 1.5H 2 O, and KAlSiO 4 .