Effects of heat treatment temperature and CeO2 content on the phase composition, structure, and properties of monazite phosphate-based glass-ceramics

The influences of heat treatment temperature and CeO2 content on the phase composition, structure, and properties of the monazite phosphate-based glass-ceramics prepared by a glass melt-quenching process were investigated. The results show that the CeO2 addition promotes the formation of monazite CePO4 phase but restrains the Fe(PO3)3 and Fe4(PO4)2O phases formed. The batches with high CeO2 content should be heat treated at higher temperatures to obtain the glass-ceramics with a single monazite CePO4 phase. Moreover, the mechanisms of the variations are discussed. At the heat treatment temperatures of ≤1200°C, the as-prepared glass-ceramics show good aqueous durability and the main networks of pyrophosphate and orthophosphate groups. The CeO2 loading can be increased up to 16 mol% from ∼9 mol% by forming the glass-ceramics through the melt-quenching process. The conclusions provide researchers with the roles of temperature and CeO2 in preparing monazite phosphate-based glass-ceramics as potential hosts for specific nuclear waste.