Immobilization of partitioned cesium- and strontium- rich waste from TRPO process in pollucite matrix

The present work developed pollucite-based waste forms suited for the immobilization of cesium- and strontium-rich waste (CSRW) derived from the TRPO process. The sintering conditions and waste loading were varied, and their effects on waste forms phase composition, microstructure, mechanical properties and durability were investigated. It was found that with a CSRW loading of 7.5 wt% and sintered at 1150 °C for 4 h, CSRW could be effectively incorporated into the pollucite waste forms, with only a minor glass phase present. The corresponding waste forms exhibited a microhardness of ∼ 563 HV and a thermal conductivity of ∼ 1.36 W·m -1 ·K -1 . Moreover, the normalized leaching rates of Cs, Sr, Ba, Rb, Fe, and Mo were 3.07×10 -2 , 2.76×10 -2 , 3.3×10 -3 , 9.9×10 -3 , 3.9×10 -3 and 3.1×10 -3 g·m -2 ·d -1 and the leaching indexes were > 9, exhibiting good chemical durability. This work demonstrated the feasibility of pollucite as a stable host material for the immobilization of CSRW.