PHOSPHORIC ACID PURIFICATION PROCESS Russian patent published in 2007 - IPC C01B25/46 

FIELD: inorganic compounds technologies.

SUBSTANCE: invention relates to the field of mineral fertilizers, food-quality phosphates, reagents, and detergents based on processing of phosphate mineral stock, in particular to extractive phosphoric acid processing processes having as objective its recovery and purification. Extraction of phosphoric acid id performed with tributyl phosphate. Process according to invention comprises double-step washing of phosphoric acid extract wherein extract is divided after first-step washing operation into two streams. One of the streams is transferred to reextraction of phosphoric acid to form low-grade product and the other stream is subjected to further washing, which is accomplished with high-quality phosphoric acid being neutralized with monovalent cation base during washing operation. Wash solution obtained after second-step washing is diluted with water and added in the first-step washing, Washed second-step extract is reextracted and re-extract is then additionally purified to remove fluorine in evaporation and bottom residue stemming operations resulting high-quality product.

EFFECT: elaborated economically efficient complex extractive phosphoric acid processing scheme allowing production of technical-grade and simultaneously high-grade (up to reagent-grade) phosphoric acid.

6 cl, 2 dwg, 3 tbl, 3 ex