METHOD OF RECOVERING FLUORINE COMPOUNDS FROM VAPORS EXITING WET PROCESS PHOSPHORIC ACID EVAPORATORS

摘要

A method and apparatus for removing fluorine compounds from solutions formed in the concentration of "wet-process" phosphoric acid is disclosed, characterized by contacting the exit vapor stream from a phophoric acid concentrating stage (2) with a scrubbing liquor that is sprayed into the vapor exit duct (42) of the phophoric acid concentrator, draining a liquid fraction from the exit duct that contains condensed fluorine compounds, and passing the remaining exit vapor stream/sprayed scrubbing liquor mixture into a cyclonic-type entrainment separator (4) where the entrained scrubbing liquor and condensed fluorine compounds are separated from uncondensed vapors, with the uncondensed vapors passing to a barometric condensor (70) where additional separation of impurities by condensation is effected. In one embodiment, identified as "single stage FSA recovery", the vapor exit duct from the acid concentrator is connected to an entrainment separator and the scrubbing liquor is contacted with the evaporator exit vapor stream by spraying the liquor into the vapor exit duct via a series of spray heads.