The Use of Partial-Replenishment Tests in Modeling the Leach behavior of Glasses

The partial-replenishment test can be an important tool in exploring the long-term leach behavior of glasses. In order to demonstrate the use of partial-replenishment test data in modeling, experiments were conducted which show that after a relatively short period test results become largely independent of exchange interval and volume exchange fraction. The results can be characterized by the ratio between these two parameters, which corresponds to the residence time. Sampling of the leachates during a given exchange interval shows that leachate concentrations quickly recover following the exchange, and that this recovery can be satisfactorily described using a simple model based on first-order approach to equilibrium at the silica saturation level.