PURIFICATION OF PHOSPHORIC ACID

摘要

. A process for the purification of phosphoric acid which comprises:a) contacting an aqueous phosphoric acid phase containing from 1% to about 55% P205 by weight and dissolved ionic metallic impurities selected from the group consisting of calcium, magnesium, aluminum and iron (II and III) with an organic extractant phase comprising a water immiscible organic solvent containing at least one water immiscible organic sulfonic acid having at least 12 carbon atoms and at least one water immiscible organic phosphate, phosphonate or half ester thereof dissolved therein to form: i. a purified phosphoric acid phase; and ii. a loaded organic extractant phase containing ionic metallic impurities selected from the group consisting of calcium, magnesium, aluminum, and iron (II and III) and P205 values; and b) separating the loaded organic extractant phase from the purified aqueous phosphoric acid phase. The water immiscible organic phosphate used in conjunction with the waterimmiscible organic sulphonic acids results in the improved process for purification of phosphoric acid by providing an increase in the extraction of ionic metallic impurities and a decrease in the extraction of P205 values from the aqueous phosphoric acid phase.