METHOD OF RESTORING EXTRACTANT IN THE EXTRACTION PHOSPHORIC ACID PURIFICATION PROCESS

摘要

FIELD: inorganic substances technologies.;SUBSTANCE: invention relates to technology of restoring extractant in the purification process of extraction phosphoric acid obtained via sulfuric acid decomposition of naturally occurring phosphates utilizing liquid extraction with tributyl phosphate. Extractant is purified by washing it with water at volume ratio (1-2):1, respectively, and temperature 20 to 55°C in one-two steps followed by transferring water phase into phosphoric acid purification process and transferring extractant to vacuum distillation stage carried out at 140-200°C and pressure 5-20 mm Hg. Resulting distillate is recycled to phosphoric acid purification process and bottom residue is otherwise utilized or sent to secondary vacuum distillation.;EFFECT: increased extractant purification degree, reduced number of process stages, and accelerated washing operation.;3 cl, 1 tbl, 5 ex