Incorporation of Ba in Al and Fe pollucite

Abstract Ba, the transmutation product of radioactive Cs, can be incorporated at levels of up to ∼0.07 formula units in Cs (1−2x) Ba x AlSi 2 O 6 aluminium pollucite formed by sol-gel methods and sintering at 1400 °C, with more Ba forming BaAl 2 Si 2 O 8 phases. The effect of Ba substitution in pollucite-structured CsFeSi 2 O 6 was also studied and no evidence of Ba substitution in the pollucite structure via cation vacancies or Fe 2+ formation was obtained. The Ba entered a Fe-silicate glass structure. Charge compensation was also attempted with a Cs + + Fe 3+ ↔ Ba 2+ + Ni 2+ scheme but again the Ba formed a glass and NiO was evident. PCT leaching data showed CsFeSi 2 O 6 to be very leach resistant.