Infra-red study of the interaction between caesium chloride and kaolinite

The interaction of CsCl with kaolinite leads to delamination of the tactoid followed by hydration of the kaolinite layer. A kaolinite-CsCl-H₂O complex is obtained. The 3700, 3674 and 3657 cm^-1 OH stretching bands of kaolinite are shifted to 3606, 3588 and 3507 cm^-1. The AlOH deformation bands are also shifted from 937 and 912 cm^-1 to 900 cm^-1. These shifts may be due to weak hydrogen bonding between the sorbed water molecules and the inner-surface OH groups. Most of the bands which are associated with perpendicular vibrations are sharpened. Thermal weight loss study shows that some of the water in the complex forms hydrates which are stable at temperatures above 500°C. From X-ray data, it appears that as a result of delamination of the tactoid and hydration of the kaolinite layer, the layers do not settle in a preferred orientation. Washed samples regain the tendency to settle in a preferred orientation and tactoids are formed. However, these tactoids differ from the original ones. The formation of the kaolinite-CsCl-H₂O complex depends on the time of grinding and the time which elapses after the components have been mixed.