Formulation of high-Al2O3 waste glasses from projected Hanford waste compositions

Abstract High alumina high-level waste (HLW) is stored at the Hanford Site. This waste will be vitrified into borosilicate glasses at the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The efficiency of the WTP operation will be strongly influenced by the loading of high Al2O3 wastes in HLW glass and the melter processing rate. A study was performed to formulate glasses with high loading of Al2O3-rich HLW and demonstrate their processability. Glasses with Al2O3 concentrations ranging from 30 to 35 mass% were designed and tested. One example glass with Al2O3 loading of 34 mass% was processed in a small-scale continuous melter. These compositions showed promising properties and good processability, suggesting that loading Hanford HLW glasses with excess of 30 mass% Al2O3 can be successfully produced at the WTP. The ability of existing glass property-composition models to predict the properties of HLW glasses with high Al2O3 content was evaluated. Viscosity and electrical conductivity model predictions appeared reasonably close to measured values, while crystallization and product consistency test model predictions were found to be significantly different from measured values.