SEQUESTRATION OF CESIUM AND STRONTIUM BY TOBERMORITE SYNTHESIZED FROMFLY ASHES

Tobermorites were synthesized from oxides and from fly ashes under mil d hydrothermal conditions, The bulk compositions of the ash-based form ulations were adjusted to give the same [Ca]/[Si + Al] ratio as for th e oxides, Selective Cs and Sr exchange with these tobermorites was mea sured, Compared to those prepared from the oxides and from class C fly ash, the tobermorites obtained from class F Ay ash exhibited superior Cs and Sr selective properties, This is apparently a result of more e xtensive Al incorporation with class F fly ash, For example, tobermori te synthesized from class F fly ash exhibited a cesium K-d (mL/g) of 3 826 while those prepared from oxides and from class C fly ash showed K -d values of 1112 and 796, respectively, under the same conditions, Th ese results suggest that fly ash waste materials can be converted into tobermorite, which can serve as a resource in the separation, immobil ization, and disposal of radioactive species such as Cs and Sr.