Cesium stabilization by engineered alkaline attack of glass for pharmaceutical containers

An innovative method for immobilizing cesium has been developed through the alkali activation of boro-alumino-silicate glass. Glass powders from discarded pharmaceutical vials, suspended in CsOH-based activating solutions yield cementitious matrices upon drying at nearly room temperature. Solid blocks are formed through bridging of adjacent particles by condensation reactions in hydrated surface layers. Silicates, borates, and aluminates released into the solution, along with atmospheric CO2 interact with Cs+ and NH4+ ions, forming additional phases, with various chemical stability. When exposed to boiling water the blocks are stable. Boro-pollucite (CsBSi2O6) formed as the result of chemical reactions in the system is stable and does not dissolve. However, boiling results in dissolution of cesium carbonate. A mixed attack by CsOH-NH4OH instead of CsOH reduces the formation of cesium carbonate, maximizing the immobilization of cesium in a stable matrix.