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

摘要

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 degrees 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 tip 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 x 10(-6) and 23 x 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 x 10(-4) g m(-2) d(-1) after 7 days. (C) 2015 Elsevier B.V. All rights reserved.