Combustion synthesis and characterization of Nd-Al codoped zirconolite-rich waste forms using CuO as the oxidant

Abstract

Zirconolite-rich composite material was rapidly obtained from combustion synthesis (CS) using CuO as the oxidant and Ti as the reductant. As the surrogate of trivalent actinides, Nd was incorporated to substitute the Ca site of zirconolite with Al2O3 as the charge compensator. The results demonstrate that Nd-bearing calcium zirconium titanium oxide (CZTO) was produced as the main phase after Nd2O3 and Al2O3 addition. Nd2O3 was consolidated into the lattice structure of zirconolite-rich waste forms with waste loading of about 20wt%. The 42 days normalized leaching rates (LRi) of Cu, Ca and Nd in the tested CNA-3 sample were evaluated to be 1.98×10−2, 7.36×10−2 and 6.35×10−5 gm−2·d−1.