EXTRACTION PHOSPHORIC ACID PURIFICATION PROCESS Russian patent published in 2001 - IPC

FIELD: inorganic compounds technology. SUBSTANCE: invention, in particular, relates to production of phosphoric acid with low impurity level suitable for use in production of industrial- and food-destination phosphates. In a process including extraction of phosphoric acid with tributyl phosphate and subsequent re-extraction of phosphoric acid from the first extract to give production acid, the two stages being performed by mixing aqueous and organic phases to form emulsion in pulsation mode and by separating the two phases in the end of each stage, washing of extract, according to invention, is accomplished with water- phosphoric acid mixture in washing solution recycling mode (repetition factor 0.7-8). Washing operation lasts until weight concentration of phosphorus pentoxide in washed out extract reaches 6-11%. Washing acid withdrawn from re- extraction stage is used in production of industrial-grade salts, and production acid is used in production of food salts. EFFECT: stabilized quality of production acid and increased yield thereof. 2 cl, 1 tbl