Dissolution of lithium disilicate glass under flow conditions

Previous research on the flow dissolution of glass has mainly focused on complex glasses like those used in the encapsulation of nuclear waste. The goal of this research was to examine how flow dissolution may affect a lithium disilicate glass. Flow experiments were conducted at temperatures of 50 °C and 95 °C and flow rates of 0.333 mL/min and 1 mL/min and then compared to static experiments at the same temperature. Results showed little difference in dissolution due to the flow rate at 50 °C but noticeable changes at 95 °C. Lithium dissolution trends indicated that the solution concentration and the total normalized mass loss increased with higher temperatures and lower flow rates. Flow had little effect on the silicon total normalized mass loss but there was a large difference at 95 °C between static and flow experiments. This was thought to be due to the higher pH in the static system increasing the dissolution of silica. While the trends for concentration were similar to those identified in previous research, those between the total normalized mass loss and flow rate were different compared to complex glasses. It was hypothesized that this difference was due to the presence of a precipitation layer that did not occur in lithium disilicate.