A polyphase geoceramic matrix for joint immobilization of the strontium-cesium and rare earth fractions of high-level waste

Polyphase geoceramic matrices of the (silico)phosphate type for joint immobilization of the strontium-cesium and rare earth fractions of high-level waste with residual actinide content were synthesized. The charge components were iron oxide, technical-grade phosphoric acid, and apatite ore dressing tails. The synthesis method involves fine dispersion of the starting materials and two-step ceramization at 920 and 910°C for 20 min. The total content of the radionuclides in the matrix is on the level of 15 wt %. The cesium leach rate under the conditions of kinetic control (at 90°C) is 5 × 10−7 g cm−2 day−1.