METHOD OF RESTORATION OF EXTRACTING AGENT IN THE COURSE OF CLEANING EXTRACTION PHOSPHORIC ACID

摘要

FIELD: technology of restoration of extracting agent in the course of cleaning extraction phosphoric acid obtained by sulfuric acid decomposition of natural phosphates by means of liquid extraction with tributyl phosphate followed by separation of aqueous and organic phases and re-extraction of phosphoric acid from organic phase by means of water.;SUBSTANCE: extraction and re-extraction are performed in pulsation columns by mixing the aqueous and organic phases for forming emulsion under action of air at extraction temperature of 30-50°C and re-extraction temperature of 40-80°C during process of mixing with water and organic phases for forming emulsion under action of air in pulsation mode when part of circulating extracting agent is separated for washing with alkaline solution and water followed by returning it to extraction stage; aqueous phase which is just alkaline solution is treated with phosphoric acid at concentration of 20-54% and volume ratio of V_alk. : (V₁ + V₂) = (0.4-2.5) : 1 at 10-60°C in two stages in succession separating the phosphoric acid flow in volume ratio of V₁:V₂ = 1: (0.5-13) obtaining salt solution at pH of 4-7 at 1st stage, pH of 1-3 at 2nd stage followed by separation of gummy agents at 1^st stage, settling and decanting and filtration at 2^nd stage.;EFFECT: reduced losses of extracting agent; enhanced purity of phosphoric acid salts.;3 cl, 1 tbl, 1 ex