THE CHANGE IN STRUCTURE OF CLAY MINERALS AND ELUTION OF CS AND SR BY HEAT TREATMENT

Abstract

 Clay minerals may change under the influence of heat treatment as follows: loss of adsorbed water, interlayer water and constitution water of clay minerals, and decomposition and recrystallization of clay minerals. Cs and Sr are adsorbed on clay minerals with different behavior and strength.Therefore, in this study, it was examined whether structural changes of clay minerals influenced on the characteristics of Cs and Sr elution by heat treatment. XRD peak intensity of kaolinite, dickite, montmorillonite and hydrobiotite changed remarkably by heat temperature. CEC of most clay minerals decreased with high temperature, however, CEC of hydrobiotite increased. The elution rate of Cs in the heated clay minerals decreased and Sr elution rate of some clay minerals increased by heat treatment. This study indicated that the physical and chemical characteristics of clay minerals were changed by heat treatment and that those changes influenced on Cs and Sr elution in the heated clay minerals.