Effect of varying Nd2O3 contents on the structure and mechanical properties of the radioactive waste form: aluminosilicate glass-ceramics

The magmatic diagenetic environment was simulated by high-temperature melting and natural cooling. A series of glass-ceramics with different Nd 2 O 3 contents were prepared by using complex component granite (aluminosilicate material). The phase evolution of the matrix at different temperatures was studied by X-ray diffraction (XRD). The structure of glass-ceramics was analyzed by infrared spectroscopy (IR) and scanning electron microscopy (SEM). The mechanical properties of glass-ceramics were also evaluated. The results showed that the glass transition of pure matrix begins at 1200 °C, and the sample with the highest degree of vitrification is obtained at 1500 °C. The addition of Nd 2 O 3 promoted the melting of Fe 3 O 4 crystal, resulting in the complete amorphous matrix when the Nd 2 O 3 amount is in the range of 20–26  wt .%. With the further increase of Nd 2 O 3 content, Nd-bearing feldspar first appeared. No raw material Nd 2 O 3 was found, indicating that the formation of Nd-bearing feldspar may increase the carrying capacity of the material. The Gaussian fitting results showed that the glass-ceramic samples with Nd 2 O 3 content of 29  wt .% are mainly composed of Q 2 and Q 3 structural units. In the EDS result, part of neodymium was clustered with small bright spots, while the spots were uniformly distributed on the sample surface as a whole. Meanwhile, the addition of Nd 2 O 3 increased the mechanical properties of the samples (3.20 g/cm 3 , 8.33 GPa for the sample with 29  wt .% of Nd 2 O 3 ). The results provide a strategy for the treatment of solid waste with radioactive residual actinides.