CLINOPTILOLITE WITH CESIUM IMMOBILIZATION TO POTASSIUM MAGNESIUM PHOSPHATE MATRIX

The possibility of potassium magnesium phosphate (PMP) matrix application for immobilization of clinoptilolite with simulator of radioactive cesium isotopes was investigated. X-ray phase analysis of the natural clinoptilolite sample has shown that it includes two main phases of clinoptilolite (Na,K)4CaAl6Si30O72·24H2O, and mordenite (Na2Ca, K2) 4Al8Si40O96 · 28H2O. In addition, impurities of SiO2, Fe2O3 and TiO2 phases are observed. To saturate clinoptilolite with cesium, 0.5 M solution of cesium chloride was used. A chemical analysis of clinoptilolite after saturation with cesium has demonstrated that the content of cesium in clinoptilolite was about 2 wt.%. After the introduction of clinoptilolite with cesium in the PMP matrix, the obtained material was identified as potassiummagnesium phosphate with the presence of clinoptilolite, mordenite, TiO2 and unreacted MgO phases. The results of the electron microscopy analysis have shown that cesium was dislocated between PMP matrix and clinoptilolite, incorporated into the PMP matrix. Normalized leaching rate of cesium from PMP matrix with 25wt.% clinoptilolite was about 3.2.10-4 g / cm2 per day after 7 days testing.