Comparative study of the sonication effect on the thermal behaviour of 1:1 and 2:1 aluminium phyllosilicate clays

The aim of this work is to compare the effect of sonication on the thermal behaviour of kaolinite and pyrophyllite. The results show that sonication produces a significant particle size reduction of both clays. Besides, this treatment modifies the thermal behaviour of these samples. Nevertheless, the change in particle size and in the modification of the thermal behaviour is different for both clays. Sonication facilitates the dehydroxylation of both clays, although, the temperature shift of the dehydroxylation is more significant for pyrophyllite than for kaolinite. Additionally, the exothermic effect at 987 °C for kaolinite is not affected by sonication while that at 1210 °C for phyrophyllite is shifted to lower temperatures.