METHOD OF REACTANT PURIFICATION FROM CAESIUM RADIONUCLIDES Russian patent published in 2009 - IPC G21F9/28 

FIELD: treatment facilities.

SUBSTANCE: invention relates to environmental protection field, territory rehabilitation, polluted by anthropogenic radioactive species. Method of ground reactant purification from caesium radionuclides consists in treatment of grounds by water solutions. Solution contains decontaminate reagents - mineral acids. They correspond mixture of sulfur and phosphoric acids with correlation of its concentrations, expressed in moles 1-3. Concentration of phosphoric acid is 0.5-2 M. Process is implemented at temperature 50-100°C with following separation of water solution with decontaminate reagents from treated ground. Then there are extracted caesium radionuclides from separated water solution with decontaminate reagents by means of feeding into solution of ferrocyanide alkaline metals or ammonium up to concentration 6·10^-4-7·10^-2 M with sediment formation, consisting caesium radionuclides, which are directed for storage. Before treatment of ground by water solution it is defined optimal processing time. Above mentioned treatment of grounds by water solution is implemented in several cycles up to receiving of rated value of ground activity by caesium. In the first cycle of ground treatment by water solution it is implemented separation of water solution from sandy and pelitic fractions of ground. Pelitic fraction is directed to storage. Sandy fraction is directed for following treatment cycles of ground by water solution. Water solution is separated from sandy fraction up to receiving of rated value ground activity by caesium. Sulfur and phosphoric acids are added up to operation concentrations into water solution with residual of decontaminate reagents in the second treatment cycle. Weight relation of liquid and solid phases is 0.5:1.

EFFECT: reduction of reactant purification time of ground from radioactive caesium, increasing of decontamination factor of ground from caesium and reduction of decontaminate reagents amount.