METHOD OF PROCESSING SOLID URANIUM-CONTAINING WASTES WITH HIGH CONTENT OF GYPSUM Russian patent published in 2025 - IPC G21F9/04 

FIELD: performing operations.

SUBSTANCE: invention relates to a method of processing solid uranium-containing wastes with uranium content of up to 0.3 wt. % and high content of calcium sulphate hydrate (more than 45 wt. %) and can be used in hydrometallurgy. Method involves a process of leaching with a nitric acid solution, wherein the excess concentration of acid in the leaching solution is 20-60 g/dm³. Leaching process is carried out at temperature from 50 to 70 °C for 1.0-1.5 hours and in ratio of solid and liquid phases S:L = 1:4-6. After leaching, the productive solution is separated from the insoluble sediment by filtration and directed for concentration, which is carried out by ion exchange on a phosphorus-containing ionite. Desorption of uranium from the saturated ionite phase is carried out with a solution of ammonium carbonate in two steps with concentration: at stage 1 – 0.4-0.8 M, at stage 2 – 1.0-1.5 M, at temperature of 30-35 °C with further thermal decomposition of carbonate complexes and obtaining ammonium uranyl phosphate hydrate.

EFFECT: achieving high values of the degree of extraction of uranium from solid uranium-containing wastes with high content of calcium sulphate hydrate (more than 45 wt %) with obtaining the end product with uranium weight fraction of more than 50 %.

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