METHOD OF PROCESSING LIQUID RADIOACTIVE WASTES Russian patent published in 2019 - IPC C02F1/28 G21F9/12 

FIELD: chemistry.

SUBSTANCE: invention relates to decontamination of liquid radioactive wastes of low and medium activity level. Method of complex treatment of liquid radioactive wastes includes stages of preliminary purification, reverse-osmosis desalination with separation of flows into permeate (filtrate) with salt content <0.5 g/l and high-salt concentrate with subsequent post-treatment of filtrate on sorbents and localization of high-salt concentrate. Ultrafiltration of the solution is carried out in two steps. First stage is performed in non-flow (frontal) mode, and the second stage is performed in flow (tangential) mode. Solution is cleaned from cesium at the stage of ultrafiltration by adding a suspension of fine sorbents based on ferrocyanides of transition metals. Desalination of liquid radioactive wastes is carried out by reverse osmosis in two successive steps and highly selective membranes for seawater desalination are used at the second stage. Concentration at the third stage of osmosis is limited to 10–50 g/l in order to prevent precipitation of poorly soluble compounds, and before the evaporation stage concentrates are subjected to oxidative decomposition of organic substances.

EFFECT: invention enables to optimize the process of filtering and reverse osmosis, reduce the amount of secondary wastes.

5 cl, 1 dwg, 1 ex