Self-Propagating High-Temperature Synthesis of Zirconolite Using CuO and MoO3 as the Oxidants

Synroc is recognized as the second generation waste form for the disposal of high-level radioactive waste (HLW). In this research, one of the mostly studied Synroc minerals, zirconolite (CaZrTi 2 O 7 ), was prepared by self-propagating high-temperature synthesis (SHS). CuO and MoO 3 were employed as the oxidants with Ti as the reductant. Different TiO 2 /Ti ratios were selected to investigate reactivity and adiabatic temperature ( T ad ) of the designed SHS reactions. Zirconolite was successfully synthesized as the main phase at varied TiO 2 /Ti ratios using CuO and MoO 3 as the oxidants. The as-synthesized samples were readily solidified with desirable density and Vickers hardness.