PHOSPHORUS ABSORPTION BY HYDRATION AND FLUORINE RECOVERY FOR SMOKE EXITING KILN IN KILN PROCESS FOR PRODUCTION OF PHOSPHORIC ACID

摘要

Disclosed is a method for phosphorus absorption by hydration and fluorine recovery for a smoke exiting a kiln in a kiln process for the production of phosphoric acid, comprising the following steps: before a smoke containing P₂O₅ and fluorine exiting a kiln is first introduced into a hydration tower, an acid liquor circulating and spraying system connected to the hydration tower is turned on, the smoke performs heat and mass transfer with the sprayed liquid, with most of the phosphoric acid produced being absorbed into the sprayed liquid; the phosphoric acid solution falling from the spraying finally enters the acid liquor circulating and spraying system via a liquid inlet; the smoke discharged from a smoke outlet then passes through a phosphoric acid fog capturing tower and a fog removing and separating tower successively, such that the phosphoric acid fog entrained in the smoke exiting the hydration tower is further captured; the concentrated phosphoric acid solution in the acid liquor circulating and spraying system can enter a phosphoric acid refining procedure, and the fluorine-containing smoke discharged from the fog removing and separating tower enters a subsequent fluorine recovery procedure. The present invention has the advantages of simplified process flow, reasonable layout, low equipment investment cost, strong adaptability, meeting environmental standards, and good recovery effects on both phosphorus and fluorine etc.