METHOD FOR CRYSTALLIZATION ISOLATION AND CLEANING OF NITRATE URANIUM HEXAHYDRATE AND DEVICE FOR ITS IMPLEMENTATION

摘要

1. Method for crystallization isolation and purification of uranyl nitrate hexahydrate, including continuous crystallization of uranyl nitrate hexahydrate from concentrated uranyl nitrate nitrate solution, separation of uranyl nitrate hexahydrate crystals and mother liquor, countercurrent washing of uranyl nitrate hexahydrate crystals with washing solution, withdrawal of mother liquor collection and unloading of washed crystals of uranyl nitrate hexahydrate, characterized in that the compositions of the concentrated uranyl nitrate solution supplied to the process and the washing solution are maintained in accordance with the ratio [UO (NO)] = 78.49 - k [HNO], where [UO ( NO)] and [HNO] -concentrations of uranyl nitrate and nitric acid in the liquid phase, wt%, 78.49 is the concentration of uranyl nitrate in crystals of uranyl nitrate hexahydrate, wt%, k is a coefficient that determines the position of the working line of the process and has numerical value from 1.50 to 2.24, preferably from 1 , 55 to 1.80, while the concentration of uranyl nitrate in the concentrated nitric acid solution of uranyl nitrate is at least 60 wt%, and in the washing solution - below the concentration corresponding to the intersection of the working line with the crystallization isotherm of uranyl nitrate hexahydrate, up to a uranium-free composition, the completion of the crystallization process of uranyl nitrate hexahydrate and the transition of uranyl nitrate hexahydrate crystals to the washing zone is carried out under isothermal conditions, the washed uranyl nitrate hexahydrate crystals are sent to a collection container filled with a washing solution displaced by crystals of uranyl nitrate hexahydrate