METHOD OF OBTAINING EXTRACTION PHOSPHORIC ACID Russian patent published in 2016 - IPC C01B25/22 

FIELD: chemistry.

SUBSTANCE: Khibiny apatite concentrate, which contains 14-40% of fraction +0.16 mm, with content 30-33% P₂O₅ and 0.72-1.10% Al₂O₃, is decomposed with mixture of phosphoric and sulphuric acids with introduction of additive of acid-soluble compounds of aluminium for 2.5-3.5 h with crystallisation of easily-filtering sediment of calcium sulphate dihydrate. Recicrulated pulp is present in decomposition zone. Obtained circulated calcium sulphate pulp in phosphoric acid in quantity 30-100% is subjected to air-cooling in mode of foam layer and ripening. Production phosphoric acid is separated by filtration. Sediment of calcium sulphate dihydrate is washed in mode of contraflow with water with formation of circulating phosphoric acid and its return to decomposition stage.

EFFECT: invention makes it possible to provide intensification of process of production of extraction phosphoric acid from Khibiny apatite concentrate.

3 cl, 1 tbl, 2 ex