Leaching of borosilicate glasses containing simulated high-level waste from the experimental and demonstration center of the mining and chemical combine in mineralized water of a granitoid formation

Abstract

Leaching of borosilicate glass samples containing 10, 15, and 20 wt % simulated high-level waste (HLW) at 20 and 90°C in mineralized water simulating the composition of underground waters on the site suggested for disposal of vitrified HLW was studied. Water was mineralized by long-term leaching of a crushed granite core sample taken from the borehole that had been sunken on the site promising for the construction of an underground repository. The leach rates and diffusion coefficients of components of the above glasses were determined. The character and extent of the influence of the varied experiment parameters on the characteristics being determined were estimated by correlation analysis. The chemical resistance of the glasses being studied to leaching in mineralized water is lower than their leach resistance in deionized water. On the other hand, interaction of glass components that passed into the solution with some components of mineralized water leads to their reprecipitation. The hypothesis that the glass surface can be passivated owing to secondary phase formation was put forward.