Simultaneous immobilization of cesium and strontium by crystalline zirconium phosphate

In the present study, simultaneous gross immobilization of radioactive Cs and Sr in zirconium phosphate was investigated by two methods. In the "dry method," a mixture of HZr2(PO4)(3) with varying amounts of CsNO3 and Sr(NO3)(2) was heat-treated at 700 degrees C for 5 h to prepare Cs + Sr immobilized samples. At Cs + Sr immobilization of 0.3 + 0.15, the leaching amounts of Cs and Sr in 1 mol.dm(-3) of HCl solution treated at 160 degrees C for 24 h were 2.9 x 10(-4)g.m(-2) and 3.9 x 10(-4) g.m(-2), respectively. In the "autoclave method," aqueous solutions containing 0.5 and 0.25 mol of CsNO3 and Sr(NO3)(2), respectively, against 1 mol of (H3O)Zr-2(PO4)(3) were thermal-treated at 150- 250 degrees C for 24 h to prepare Cs + Sr immobilized samples; immobilization of Cs and Sr was observed at 150 degrees C. The immobilized amount of Cs and Sr increased as the treated temperature increased, while the leaching amounts of Cs and Sr in 1 mol.dm(-3) of HCl solution treated at 160 degrees C for 24 h decreased. The amount of immobilized Cs and Sr on (H3O)Zr-2(PO4)(3) at 250 degrees C were 0.30 and 0.20, and leaching amounts of Cs and Sr were 1.0 x 10(-3) g.m(-2) and 1.4 x 10(-3) g.m(-2), respectively. (C) 2022 The Ceramic Society of Japan. All rights reserved.