Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

Abstract

Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water during the corrosion process, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other simultaneously occurring processes. In this work, an inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting simulated nuclear waste glass coupons, the 6-oxide CJ-6 and the 26oxide SON68, with a non-aqueous solution of 6 LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-offlight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6 Li is faster in the simplified CJ-6 (D6Li ≈ 4.0-8.0 × 10-21 m 2 /s) compared to the more complex SON68 (D6Li ≈ 2.0

Impact of alkali on the passivation of silicate glass

“…A higher selectivity of the gel is observed for Na, K, and Cs rather than Li following the order K > Cs > Na ) Li Such an order is surprising at first, considering that previous works have shown a higher mobility of Li than the other cations, with an unexpected ability of Li to diffuse inside the pristine glass in aqueous 9 and non-aqueous media. 26,27 However, while the capacity of aqueous Li to diffuse in glass was observed, it was not quantified. The order observed here is close to the order of the Hofmeister series (also called lyotropic series).…”

Various effects of magnetite on international simple glass (ISG) dissolution: implications for the long-term durability of nuclear glasses

“…The behavior of iron into the surface as well as methylene blue, a nonreactive 1 nm diameter molecule, and Li, which has been shown to diffuse into the pristine glass at a rate higher than other hydrous species, were monitored. 49 Figure 10 shows a comparison of a monolith before the addition of magnetite and 6 months after addition (at which time iron was seen incorporated into the alteration layer). Since these components are not within the glass composition they cannot be normalized and thus only give a qualitative view of diffusion into the alteration layers.…”

Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information

“…The components, preparation, and leaching procedure of the SON68 glass have been described elsewhere [20,27]. In brief, it was made by batching carbonates and oxides of the various metals, melting in a furnace, and quenching on a stainless steel plate.…”

“…This virtue is very valuable in glass corrosion research. As mentioned earlier, isotopically enriched glass samples have been introduced to elucidate the corrosion mechanisms of glass, and SIMS has been a major technique to characterize isotopic depth profiles in these samples [27] 56 Fe + (m/z = 55.935), and a minimum mass resolution of 2500 is required to distinguish them. In practice, at least twice the minimum mass resolution is required to obtain reasonable measurement precision.…”