ABSTRACTA study was conducted on glasses based on a simulated transuranic waste with
high concentrations of ZrO2and Bi2O3 to
determine the compositional dependence of primary crystalline phases and
liquidus temperature (TL). Starting from a baseline composition, glasses were formulated by
changing mass fractions of Al2O3,
B2O3, Bi2O3, CeO2,
Li2O, Na2O, P2O5,
SiO2, and ZrO2, one at a time, while keeping the
remaining components in the same relative proportions as in the baseline
glass. Liquidus temperature was measured by heat treating glass samples for
24 h in a uniform temperature furnace. The primary crystalline phase in the
baseline glass and the majority of the glasses was zircon
(ZrSiO4). A change in the concentration of certain components
(Al2O3, ZrO2, Li2O,
B2O3 and SiO2) changed the primary phase
to baddeleyite (ZrO2), while cerium oxide (CeO2)
precipitated from glasses with more than 3 wt% CeO2. Zircon
TL was strongly increased by Al2O3,
Zrb2 and CeO2, and slightly by
P2O5 and SiO2; decreased strongly by
Li2O and Na2O and moderately by
B2O3. A first-order model was constructed for
TL as a function of composition for zircon primary crystalline phase
glass.
Results from Phase 1, 2, and 3 Studies on Nepheline Formation in High-Level Waste Glasses Containing High Concentrations of Alumina