Natural magmatic granite as matrix for immobilizing simulated An4+ waste

Abstract In nature, many rocks contain radionuclides, and returning radioactive waste to nature is an environmentally friendly way. In this work, a natural magmatic granite rock has been studied as a host matrix for simulated An4+ waste disposal. The blank granite, in the form of powder, was firstly treated by muffle furnace heating in the temperature range of 800 °C to 1400 °C. It was found that the lowest crystallinity of the samples was obtained at 1300 °C. Moreover, 8 wt.% of simulated tetravalent actinides (CeO2) could be successfully immobilized in the natural granite at 1300 °C for 60 min. Raman results show the structure disordering in samples tends to increase with the increased amount of CeO2. SEM-EDS observation shows that the distribution of Ce was relatively uniform in the matrix. Moreover, the hardness of solidified body is comparable to traditional glasses and it decreases with the increase of CeO2 content.