Preparation of homogeneous (Th0.8U0.2)O2 powders by mechanical blending of Th(C2O4)2·6H2O and U(C2O4)2·6H2O powders

Thorium oxalate and uranium (IV) oxalate powders were prepared and characterized by chemical, TGA/DTG, IR and X-ray diffraction analysis. Th(C2O4)2·6H2O and U(C2O4)2·6H2O powders (80% Th and 20% U) were mechanically mixed in a diagonal rotating drum for 3 h. Mechanically mixed oxalates were decomposed at 623 K, calcined at 1173 K for 24 h in air and reduced for 2 h at 923 K in hydrogen atmosphere. The powders were compacted into pellets and sintered in flowing CO2 at 1373 K for 1 h. The XRD pattern of (Th0.8U0.2)O2 obtained showed that a complete solid solution was formed.