METHOD FOR PROCESSING MONAZITE CONCENTRATE Russian patent published in 2021 - IPC C22B59/00 C22B60/02 C22B3/06 C22B3/44 

FIELD: rare earth elements extracting.

SUBSTANCE: invention relates to a technology for extracting rare earth elements (REE) from monazite concentrate and can be used in the chemical and metallurgical industries. The monazite concentrate is treated with phosphoric acid with a concentration of 35-45 wt.% at a temperature of 60-80°C with the transfer of rare earth elements and thorium to sulfonic cationite. After that, the sulfonic cation exchanger is separated from the phosphoric acid solution and the undecomposed residue, and the REE is desorbed. From the sulfonic cation exchanger, REE and thorium are desorbed together at a temperature of 70-90°C with a solution of sodium nitrate or sodium chloride with a concentration of 5.0-5.3 mol/l to obtain an eluate. The eluate is neutralized with sodium hydroxide or sodium carbonate, first to pH 4.0-4.4 with precipitation and separation of thorium concentrate, and then to pH 7.35-7.5 with precipitation and separation of the REE concentrate.

EFFECT: extraction of up to 89.8% of REE into a non-radioactive concentrate and production of thorium-rich cakes, reduction of the temperature of phosphoric acid decomposition, solution of the problem of desorption of radionuclides from sulfonic cation exchanger and exclusion of the use of hydrochloric acid for desorption of REE.

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