IMPROVED DEVICE FOR PREPARING PHOSPHORIC ACID FROM KILN EGRESSION FLUE GAS OF PHOSPHORIC ACID PROCESS OF KILN METHOD, AND PHOSPHORIC ACID PREPARING PROCESS

摘要

Provided are improved device for preparing phosphoric acid from kiln egression flue gas of a phosphoric acid process of a kiln method, and a phosphoric acid preparing process. The process comprises: introducing the kiln egression flue gas that contains P2O5 and fluorine to a hydration tower (1), and before the introducing, opening an acid liquor circulation spraying system connected to the hydrated tower (1), wherein a great portion of the phosphoric acid generated in the heat and mass exchanging between the flue gas and spraying liquid is absorbed into the spraying liquid; allowing the sprayed phosphoric acid solution to circulate into the acid liquid circulation spray system finally through a liquid inlet (14); then allowing the egression flue gas from an egression flue gas outlet (12) to pass through a phosphoric acid gas scrubber (3) and an electrostatic mist precipitator (4) in sequence, so that phosphoric acid gas mixed in the egression flue gas from the hydrated tower (1) is further collected, and the concentrated phosphoric acid solution in the acid liquid circulation spray system can enter a refining process; and allowing the flue gas containing fluorine from a mist separation tower to enter a follow-up fluorine recycling processing.