The crystal-chemical principle in designing mineral-like phosphate ceramics for immobilization of radioactive waste

Abstract

The crystal-chemical principle of designing multicomponent compounds of the desired structure was applied to the development of solid matrices for immobilization of radioactive waste components. The approach to designing mineral-like crystalline materials was based on the structural features and isomorphism concept. The structural types of monazite, kosnarite (NZP), and langbeinite were considered as matrices for the incorporation of simulated wastes containing f elements and certain uni-, bi-, and trivalent elements involved in radiochemical processes. Phosphates of complex cationic compositions were prepared and studied by X-ray phase analysis and scanning electron microscopy. The main phases of the expected structures (monazite, kosnarite, langbeinite) and additional phases (Al and Fe phosphates, Zr pyrophosphate, Pd metal) were identified. The phase formation in the temperature range 80–1300°C was analyzed.