Ceramics-Silikáty 43, (4) 175 - 180 (1999)

The presented Monte Carlo method solves the mathematics of transition state theory and describes the glass dissolution process on a microscopic scale. In the model, the glass is considered as a random mixture of a slowly dissolving, solubility limited component and a fast dissolving component. As the model parameters are similar to those in the Grambow model, the parameters of both models can be compared with each other, as well as with experimental values. The Monte Carlo method is used to investigate recent experimental results according to which the protection provided by the gel should be the major factor determining the glass dissolution rate. Although these results contradict the Grambow model, they are consistent with the presented simulations: protection by the gel is indeed important in glass dissolution. On a qualitative level, the simulation results agree with experimental observations. In particular, protective surface layer is expected(1) in static tests, (2) at high surface to volume ratios and (3) at long leaching times.