Stability of simulated wasted forms (Sr1-1.5xYx) TiO3 immobilizing 90Y

Abstract

In order to study the stability of perovskite-type SrTiO3 used for immobilizing Y3+, Sr (NO3)2, TiO2 and Y2O3 are used as starting materials. The synthesized Y2O3-doped SrTiO3 can be generally represented as Sr1-1.5xYxTiO3 (0≤ x≤0.12) with the high temperature solid reaction. The phases, structures and microcosmic shapes of synthetic condensates are characterized by the X-ray diffraction, Raman and scanning electron microscopy, and long-term chemical stability is studied at 90 ℃. The results indicate that the phases of compounds change from perovskite to pyrocholre phase when the value of x is more than 0.08. The leaching rates of Sr2+ and Y3+ in waste form increase with the increase of immersion time. The highest leaching concentrations of Sr2+ and Y3+ for 42-day immersion are no more than 0.004 and 0.02 μg·mL-1, respectively.