ATTENUATION OF GLASS DISSOLUTION IN THE PRESENCE OF NATURAL ADDITIVES

The dissolution kinetics of silicate glasses in aqueous environments i n systems which included a variety of natural crystalline solids in ad dition to the glass itself and the aqueous phase are reported. The res ults demonstrate the possibility of a dramatic decrease in the rate of dissolution of silicate glass in the presence of certain varieties of olivine-based materials. This decrease in dissolution rate was shown to be due to the fact that these additives consist mostly of Mg-based material but also contain minor amounts of Al and Ca. The combined pre sence of Mg with these minor species affected the corrosion rate of th e glass as a whole, including its most soluble components such as boro n. This study has potentially important implications to the durability of glasses exposed to natural environments. The results may be releva nt to the use of active backfill materials in burial sites for nuclear waste glasses, as well as to better understanding of the environmenta l degradation of natural and ancient glasses.