Immobilize Nd2O3 as simulated nuclear waste in silicate-apatite glass-ceramics

The solidification of nuclear waste has far-reaching developmental implications. Nuclear waste management is not only essential for the earth’s ecological balance but also can address the increasing depletion of human exploitable resources in the future. Scientists are dedicated to finding a better solidification matrix and ensuring the sustainable development of the nuclear industry in search of alternative energy sources. The present work has fabricated a simulated nuclear waste form using a sintering process of diopside. The results have shown that the Fe element in diopside granite porphyry shows an impact on the amorphization process and mechanical properties of the final waste form. Moreover, the study finds a natural analog in the glassy bulk, i.e. (Ca2Nd8(SiO4)6O2 or (K, Na)Nd9(SiO4)6O2), which can solidify the simulated trivalent actinide of Nd3+. The FT-IR results suggested that the polymerization degree of glass components in waste form decreased initially and then increased with Nd2O3 doping. Q3 unit is considered to be a key component in the waste forms. Finally, the loading capacity of Nd2O3 in waste form reached 19 wt.%. The waste form has the characteristics of glass-ceramics containing a silicate-apatite structure that is evenly distributed and has a quite considerable prospect for mechanical properties.