METHOD OF PURIFYING PHOSPHATE-FLUORIDE CONCENTRATE OF REE Russian patent published in 2014 - IPC C01F17/00 C22B59/00 C22B3/08 

FIELD: chemistry.

SUBSTANCE: invention relates to purification of a phosphate-fluoride concentrate of rare earth elements (REE), obtained in the complex apatite processing. A method of purification of the phosphate-fluoride concentrate of REE, which contains admixtures of calcium and thorium, includes processing of the concentrate with a solution of sulphuric acid with a concentration of 4-6 wt % in the presence of sulphoxide cationite. REE, admixtures of thorium and calcium are absorbed by sulphoxide cationite, transfer of fluorine together with phosphorus into the sulphuric acid solution, separation of the sulphuric acid solution from sulphoxide cationite, desorption from cationite of REE and admixtures of thorium and calcium with an ammonium salt solution with obtaining desorbate and its neutralisation with an ammonium compound in three stages. At the first stage neutralisation is carried out until pH 4.2-5.0 is achieved with formation and separation of a thorium-containing residue, at the second stage - until pH 7.0-7.5 is achieved with formation and separation of a concentrate of REE, and at the third stage - until pH not less than 8.5 is achieved with formation and separation of a calcium-containing residue.

EFFECT: invention ensures a high degree of purification of REE concentrate from phosphorus, thorium and fluorine and increase of REE content in the purified concentrate, as well as reduction of energy consumption.

7 cl, 4 ex