Properties and vibrational spectra of iron borophosphate glasses/glass-ceramics containing lanthanum

Abstract

Glass forming ability, structure and properties of La2O3 containing iron borophosphate compounds have been studied by XRD, SEM, FTIR, DTA, Raman spectroscopy and aqueous dissolution rate. The results show that the 36Fe2O3–10B2O3–54P2O5 glass with 3 mol% La2O3 is homogeneously amorphous. Partial crystallization occurs for the glass containing up to 6 mol% La2O3 and the insoluble lanthanum is mainly concentrated in the formed crystalline LaPO4. The structure of the samples is mainly based on pyrophosphate, orthophosphate and [BO4] units, and becomes more depolymerized with addition of La2O3. Moreover, Tg values increase with La2O3 content in the glass forming range. The dissolution rates of the studied glasses are about 10−9 g cm−2 min−1, demonstrating that the studied glasses and glass-ceramics posses high aqueous chemical durability. The doped La2O3 and the formed LaPO4 crystal insignificantly affect the dissolution rates of the base glass. The conclusions indicate that the studied iron borophosphate glasses are potential hosts for the disposal of high-level nuclear wastes which are rich in lanthanum.