Research on the Effect of Silica Gel in the Formation of Glass Solidified Body Containing Radioactive Iodine: Structure and Properties

Maximizing the retention of radioactive iodine in the solidified body is the fundamental solution to handling iodine-containing silica gel waste. Herein, the waste was directly treated as one of the raw components of the glass, and the B–Bi–Zn–silica gel material was prepared at 550 °C. Research showed that silica gel was beneficial in increasing the density of the glass to 2.03 g·cm–3. The addition of silica gel caused the formation of a new crystalline phase (Zn2SiO4) in the glass. The glass transition temperature of the B–Bi–Zn glass was 337 °C. The silica gel had no effect on the glass transition temperature of the glass but decreased the heat of the reaction of the material. In addition, it could be concluded from the infrared spectrum that silica gel had a significant effect on the structural unit of the B–Bi–Zn material, and the intensity of the structural unit in the absorption band of 400–1600 cm–1 was weakened. The iodine element was uniformly distributed in the cured glass, and its leaching result of 7 days was 1.1 × 10–4 g·m–2·d–1, indicating that the immobilized matrix of iodine-containing glass-ceramics was stable.