METHOD FOR EMBEDDING SODIUM NITRATE CONTAINING LIQUID RADIOACTIVE WASTES IN CERAMIC MATRIX Russian patent published in 1997 - IPC

FIELD: recovery of sodium containing liquid radioactive wastes. SUBSTANCE: method involves mixing of liquid radioactive wastes with ceramics-forming material, nitrate-ion reducing agent (carbamide in our case), and mineralizer whose function is performed by ammonium silicofluoride. Used as ceramics-forming material is bentonite, mixture of tripolite and aluminium hydroxide, as well as loam. Carbamide content should be 80% above stoichiometric value. Mixture is dewatered to residual moisture content not over 10% by weight at temperature of maximum 100 C. Then mixture is heated to 100-180 C for 6-8 h and after that, from 180 to 900 C for at least 4 h, annealed at 900 C for at least an hour, and cooled down. EFFECT: eliminated emission of toxic radioactive nuclides during their curing, low porosity of ceramics-like product obtained resulting in its resistance to washing radionuclides out of it. 4 cl