LIQUIDUS TEMPERATURES OF HLW-GLASSES WITH ZIRCONIUM-CONTAINING PRIMARY CRYSTALLINE-PHASES

Three empirical models are investigated for predicting liquidus temper atures (T-L) as a function of glass composition for high-level waste ( HLW) glasses with zirconium-containing primary crystalline phases. The three models are: (1) first-order multiple regression, (2) first-orde r single regression, and (3) second order multiple regression. For eac h of two HLW data sets and their union, the models were developed usin g least squares regression on data from glasses with any zirconium-con taining primary phase, and for the subset of glasses with zircon (ZrSi O4) as the primary phase. The fitted models, evaluations of their perf ormances, and interpretations of results are presented. The first-and second-order models fit very well for four of the six combinations of data set (A, B, A + B) and primary phase (zircon, zirconium-containing ), and reasonably well for the other two combinations. For the composi tion regions and primary phases studied, T-L is: (i) increased by ZrO2 , Al2O3, and MgO, (ii) decreased by Na2O and Li2O, and (iii) moderatel y to negligibly affected by SiO2, B2O3, and CaO. (C) 1997 Elsevier Sci ence B.V.