Synthesis of the chemically durable glass-ceramic matrix for radioactive waste immobilisation

Abstract

The Strontium oxide (SrO) loaded borosilicate glass-ceramics were synthesised, and the effect of loading on phase and chemical durability of the matrix was explored. The glass of composition 53.6SiO2-5.6B2O3-8Na2O-2.4BaO-8CaO-2.4Al2O3-10SrO-10TiO2 and a series of samples, loaded with varying content of SrO (from 10 to 25 mol%) were prepared through the melt-quench method. The ceramic phase in the samples is getting more pronounced with the increasing content of SrO from 10 to 25 mol%. The elemental mapping of the matrix has revealed a homogeneous distribution of Sr element throughout the matrix. The normalised leaching rates of Si (LRSi), B (LRB), Ba (LRBa), Ca (LRCa), Sr (LRSr) and Ti (LRTi) were obtained as 1.22 × 10−8, 3.72 × 10−9, 3.58 × 10−10, 3.32 × 10−9, 1.02 × 10−8 and 6.89 × 10−12 g. m−2. day−1, respectively, after 30 days with the loading of 25 mol% of SrO. The chemical durability results suggest that glass-ceramic wasteforms with a perovskite phase are advantageous for immobilisation of Short-lived radionuclides such as Sr etc.