Component effects on crystallization of RE-containing aluminoborosilicate glass

Lanthanide-aluminoborosilicate (LABS) glass is one option for immobilizing rare earth (RE) oxide fission products generated during reprocessing of pyroprocessed fuel. This glass system can accommodate a high loading of RE oxides and has excellent chemical durability. The present study describes efforts to model equilibrium crystallinity as a function of glass composition and temperature as well as liquidus temperature (TL) as a function of glass composition. The experimental method for determining TL was ASTM C1720-11. Typically, three crystalline phases were formed in each glass: Ce-borosilicate (Ce3BSi2O10), mullite (Al10Si2O19), and corundum (Al2O3). Cerianite (CeO2) was a common minor crystalline phase and Nd-silicate (Nd2Si2O7) occurred in some of the glasses. In the composition region studied, TL decreased as SiO2 and B2O3 fractions increased and strongly increased with increasing fractions of RE oxides; Al2O3 had a moderate effect on the TL but, as expected, it strongly affected the precipitation of Al-containing crystals.