Solid-state reaction synthesis and aqueous durability of Ce-doped zirconolite-rich ceramics

In this study, Ce-doped zirconolite-rich ceramics were prepared by solid-state reaction process using cerium as the surrogate of tetravalence actinide nuclide. The occupancy of Ce in the waste forms was investigated. The aqueous durability of Ce-doped zirconolite-rich ceramic was examined as well. The results show that zirconolite and pseudobrookite coexisted after being sintered at 1200 °C for 6 h. Meanwhile, perovskite is inevitable generated during the process. CeO2 can be successfully incorporated into the lattice structure of the zirconolite-rich ceramics. The maximum containing capacity of CeO2 is up to 14.95 wt% or y = 0.4. The normalized elemental leaching rates of Ce and Ca are fairly constant in low values of 1.2 × 10−6 and 2.3 × 10−2 g m−2 d−1 after 28 days. The normalized leaching rate of Fe is also in a low value of 2.9 × 10−4 g m−2 d−1 after 7 days.