The effects of temperature and composition on the solubility of chromium in multi-component alkali-borosilicate glass melts

The solubility of Cr in waste glass melts has an enormous impact on the cost and schedule of waste vitrification in the U.S. The solubility of Cr was studied in the context of liquidus temperature (T_L) in this study, which required development of new, more accurate, experimental methods.; It was hypothesized that the solubility of Cr in glass melts was influenced by its ability to achieve an acceptable oxygen coordination environment within the cages of the network structure. The flexibility of these network cages to accommodate Cr is related to the concentrations and potentials of other ions in the melt. This led to the development of a model that relates the ion potential (IP) of melt components to T_L.; The IP model was found to accurately predict the T_L of glasses in the spinel ([Fe,Ni,Mn][Fe,Cr,Mn]₂O₄) primary phase field. The model was rigorously validated and compared to other existing models. For the fundamental assumptions of the model to be valid, it must also be capable of predicting the effects of composition on T_L of alkali-borosilicate glasses in other primary phase fields. The model was applied to simulated waste glass melts in the zircon (ZrSiO₄) primary phase field with equal success.; The impacts of this study include a better understanding of the fundamental processes that affect the solubility of components in multi-component alkali-borosilicate melts. This model can be directly applied to predict T_L of waste glass melts in the two most important primary phase fields and with further development can be applied to prediction of T_L of other multi-component silicate glass melts covering a variety of primary phase fields.