Investigations on the structural evolution and aqueous durability of [CsxBay][Fe3+2y+xTi4+8-2y-x]O16 ceramics for radioactive cesium storage

Hollandite ceramics are considered as a promising host matrix for cesium immobilization. In the paper, [Cs x Ba y ][Fe 3+ 2 y + x Ti 4+ 8-2 y - x ]O 16 (0.3 ​≤ ​ x , y  ​≤ ​0.75) ceramics were synthesized by solid-state reaction method using 133 Cs and 133 Ba as the substitutes for radioactive Cs and its daughter product Ba. It was found that the as-prepared (Cs,Ba)-hollandite solid solution shows a tetragonal structure ( I 4/m) with >90% crystallinity and good Cs retention at 1250 ​°C. Moreover, the normalized release rates of Cs and Ba are in the order of 10 −3  ​g ​m −2  ​d −1 for 28 days, exhibiting excellent aqueous durability.