A Crystal-Chemical Approach in the Development of Phosphate Materials as Environmentally Safe Chemical Forms of Utilization of Spent Cs-Containing Ferrocyanide Sorbents

摘要

Crystalline materials are developed as environmentally safe forms of chemical binding of components of spent cesium-containing ferrocyanide sorbents. Data on cationic compositions of ferrocyanides are summarized. Using structural-chemical modeling, compositions based on orthophosphates of framework structure, crystallizing in the structural type of langbeinite mineral, are chosen for the immobilization of cesium and ferrocyanide cations. The cationic composition includes cesium, some bivalent d elements, iron (molar ratio 2 : 3 : 2), and the cations added. The substances synthesized are characterized by X-ray phase analysis, DSC, and IR spectroscopy. Upon heat treatment of the samples for 5 h at 800 deg C, cesium does not pass to the gas phase. The leaching rate on the fifth day at 90 deg C in the dynamic mode was R velence 3 X 10~(-5) g cm~(-2) day~(-1). The results of thermal and hydrolytic tests show that the crystalline forms chosen enhance the safety barrier for the incorporated cesium in the course of prolonged storage with isolation from the biosphere.