Self-propagating synthesis of Nd2O3-incorporated zirconolite/Mo composites and their aqueous durability

In this study, zirconolite/Mo composites were rapidly synthesized by a self-propagation reaction that uses MoO 3 as the oxidant accompanied with pressing. Zirconolite is one of the several materials that are being researched as host for lanthanides and actinides in nuclear waste . Nd was used in this study as a surrogate for actinides and was substituted into zirconolite at a stoichiometric ratio to charge balance the Ca and Zr sites (nominal formulation of Ca 1-x Zr 1-x Nd 2x Ti 2 O 7 ). Perovskite , zirconia, and rutile were generated as the minor phases with the addition of Nd 2 O 3 . The XRD results demonstrated that the Nd 2 O 3 loading is approximately 30 wt%. Nd was mainly incorporated into the lattice structure of zirconolite and perovskite. A 42-day leaching test of the Nd-bearing zirconolite/Mo composite showed that the computed normalized leaching rates for Ca and Nd at fairly low values of 9.02 × 10 −2 and 2.10 × 10 −4  g m −2  d −1 , respectively.