METHOD OF RECOVERING RARE-EARTH ELEMENTS FROM EUDIALYTE CONCENTRATE SOLUTION SUBJECTED TO HYDROCHLORIC ACID DECOMPOSITION

摘要

FIELD: mining industry.;SUBSTANCE: invention relates to rare-earth element recovery technology in integrated processing of mineral stock, especially to hydrogen chloride technology of eudialyte concentrate. Method according to invention comprises introduction of nitrate ion into initial chloride solution containing rare-earth and impurity elements. Chloride-nitrate solution thus obtained is treated with tributyl phosphate extractant to transfer nitrates of rare-earth elements and a part of impurity elements into first organic phase, which is then separated from chloride-nitrate solution to form first extract and first raffinate containing major part of impurity elements. First extract is washed with nitrate solution and wash solution is then returned into initial chloride solution. Rare-earth element nitrates are reextracted with water and first reextract is separated. Concentrated 35-37% hydrochloric acid is added to the first raffinate to provide 5-10% excess of the acid relative to nitrate ion content. Raffinate is treated with tributyl phosphate to transfer nitric acid into second organic phase and to form chloride solution of the major part of impurity elements. Second organic phase is separated to form extract and second raffinate, after which nitric acid is reextracted from the second extract with alkali solution to form second reextract in the form of nitrate solution, which is used to wash the first extract.;EFFECT: increased rare-earth element recovery efficiency under better environmental conditions.;5 cl, 1 dwg, 3 ex