Method for hydration absorption of phosphorus and recovery of fluorine from flue gas discharged from kiln of kiln-method phosphoric acid technology

The invention discloses a method for hydration absorption of phosphorus and recovery of fluorine from flue gas discharged from a kiln of kiln-method phosphoric acid technology, and the method comprises the following steps: first, P2O5 and fluorine-containing flue gas discharged from the kiln is introduced into a hydration tower, and before the P2O5 and fluorine-containing flue gas discharged from the kiln is introduced into the hydration tower, an acid liquid circulation spray system connected with the hydration tower is started, mass and heat transfer between the flue gas and spraying liquid is performed, most of generated phosphoric acid is absorbed into the spraying liquid, spraying and down-falling phosphoric acid solution enters finally into the acid liquid circulation spray system through a liquid inlet, the flue gas discharged from a flue gas outlet sequentially passes through a phosphoric acid mist catcher tower and a demisting separation tower, phosphoric acid mist entrained in the hydration tower fl