Rapid disposal of simulated Ce-bearing radioactive soil waste using self-propagating synthesized zirconolite-rich waste matrice

Simulated radioactive soil waste has been immobilized rapidly by self-propagating high-temperature synthesis (SHS) using CuO as the oxidant. CeO 2 was incorporated into the soil waste as the surrogate of radioactive actinide nuclides. The phase composition, microstructure, elemental distribution, density and chemical durability of obtained waste forms have been characterized. These results show that the radioactive soil waste forms were successfully prepared with zirconolite (2M-CaZrTi 2 O 7 ), soil (SiO 2 ) and Cu as the main phases. Simulated nuclide Ce was successfully immobilized in the solidified zirconolite-rich ceramic body. Moreover, the radioactive soil waste solidified body exhibits excellent chemical durability. The normalized leaching rates (42 d) of Si and Ca are in low values of 4.1 × 10 −3 and 2.5 × 10 −3 g m −2 d −1 , while that of Ce is kept as 10 −4 − 10 −6 g m −2 d −1 within 42 days. This result indicates a potential application of SHS for the safety disposal of radioactive contaminated soil waste.