METHOD OF CLEANING SANDY SOIL FROM RADIONUCLIDES Russian patent published in 2011 - IPC G21F9/28 

FIELD: physics, nuclear.

SUBSTANCE: invention relates to environmental protection, rehabilitation of territories contaminated with medium and low specific activity level radio nuclides. The method involves initial breaking of soil aggregates, surface muddy layer covering sand grains and pebbles, with mechanical separation of the initial soil into pebbles (3-100 mm) and pulp containing particles with size (<3 mm). After separation and washing, the pebbles are added to the process cycle. Through water-gravity separation, the pulp is divided into a sand fraction (>0.1 mm) and a fine-dispersed fraction (<0.1 mm), which, after thickening and dehydration, is taken to the radioactive waste storage. The sand fraction is washed with water, dehydrated and subjected to reagent treatment with 0.5-1 M sulphuric acid solution in an autoclave at temperature 100-140°C, with ratio of the liquid to the solid phase equal to 0.5/1-1/1, at the end of which the reagent solution is separated and the soil is washed with water. The separated reagent solution and the water used to wash the soil are mixed. Radionuclides are precipitated and the precipitate is taken to the radioactive waste storage. After reagent treatment and washing with water, the sand fraction is divided into a fine-dispersed (<0.1 mm) and a sand (>0.1 mm) fraction. After thickening and dehydration, the fine-dispersed fraction is taken to the radioactive waste storage and the sand is returned to the collection site.

EFFECT: less amount of reagent required for decontamination while maintaining the value of the decontamination factor.

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