Release and Diffusion in Clay of Elements Leached from a Borosilicate Glass

The degradation of a borosilicate glass in wet clay leads to the release and diffusion into the clay of the various constituent elements of the glass. An apparatus has been set up in order to study these processes. Tests have been conducted using Boom clay and the borosilicate glass 1117 at 50 and 75 °C. Comparative tests have also been conducted using the French glass SON 68. It appears that, at least up to 225 days, the glass degradation increases linearly with time. No saturation phenomena are apparent. In order to describe the distribution of the different elements in the clay it appears necessary to subdivide the elements into two groups according to their solubility in the interstitial clay water. The values obtained for the diffusion coefficients are presented and discussed.