Effect of cerium oxide on phase composition, structure, thermal stability and aqueous durability of sodium-iron-boron-phosphate based glasses

In this paper, the effect of CeO2, as the surrogate for actinide oxides and with concentrations deliberately higher than the solubility limit of the baseline glass, on phase composition, structural features, thermal stability and aqueous durability of sodium-iron-boron-phosphate (SIBP) based glasses/glass and crystal composites prepared by melt-quenching process was investigated. The results show that, at the acceptable melting temperature of 1200 degrees C, the solubility limit of CeO2 in the SIBP baseline glass is about 10 mol% and the incorporation of CeO2 higher than the solubility limit induces the precipitation of monazite CePO4 phase. Moreover, the structural variations, thermal stability and the precipitation of monazite phase induced by the CeO2 addition are discussed. Generally, the prepared SIBP based glasses/composites containing up to 25 mol% CeO2, with and without monazite phase, show acceptable thermal stability and good aqueous durability. The conclusions provide researchers with the roles of CeO2 in phase composition, structure features and properties of SIBP glasses as potential hosts for immobilization of specific HLW which are rich in sodium and actinides. (C) 2021 Elsevier B.V. All rights reserved.