Non-volatile immobilization of iodine by the cold-sintering of iodosodalite.

A cold-sintering process at a very low temperature (300 °C) achieved stable immobilization of simulated radioiodine waste incorporated in sodalite (iodosodalite). The reported sintering temperature was much lower than conventional ceramic waste form processing temperatures (600-1100 °C) and had no effect on the stability of the loaded iodine waste. Excellent iodine retention (>93%) with relative sintered density 91% were achieved by the cold-sintering at 300 °C, respectively. The sintered body exhibited a micro-hardness value of 3.9 ± 0.1 GPa and compressive strength of 198 ± 11 MPa. The seven-day product consistency test found iodine leaching rates on order of the magnitude 10 g/m⋅d. These results are the first example of the low temperature consolidation of iodine-bearing sodalite without using any additional material (e.g. glass, cement, etc.). High retention of the loaded simulated radioiodine without volatilization warrants the cold-sintering process for the environmental-friendly disposal of radioiodine.