The liquidus temperature (TL) of rare earth (RE) was determined for alumino-borosilicate glasses for
treating americium and curium that have been studied previously. Their work
covers a wide range of glass composition with various crystalline phases as
primary phase. Present work is aimed at understanding the effect of glass
composition on TL for waste glasses designed for vitrifying RE oxides wastes. In a
sufficiently narrow composition region, this effect can be represented by a
first-order model fitted measured TL versus composition data. Test glasses were formulated by varying of
component fractions one-at-a-time. The glasses contained SiO2,
B2O3, and Al2O3 as glass formers
and Nd2O3 with CeO2 as simulated RE waste.
Twenty glasses were made to investigate crystallization as a function of
temperature and glass composition. The primary crystalline phase was
Ce-borosilicate (Ce3BSi2O10), secondary phases
were Al-containing crystals (Al2O3 and
Al10Si2O19), and crystalline
CeO2. A first-order model was fitted to crystal fraction versus glass
composition data. Generally, SiO2 and B2O3 tend
to suppress crystallization, Al2O3 has little effect, and,
as expected, RE components (Nd2O3 and CeO2)
promote it. The correlation coefficient, R2, was 0.89 for the primary crystalline phase TL as a linear function of composition.