Patent ID: 6666973
Filing Date: 2003-12-23
Classification: C02F

Abstract:
A method of fixing and precipitating fluorine and phosphorus from waste water wherein the waste water includes a fluorophosphate compound, the method comprising the steps of adding hydrochloric acid to said waste water within a treating vessel, said hydrochloric acid being added in an amount so that a concentration of said hydrochloric acid in said waste water is in the range of 2% to 10% by weight, heating within said treating vessel said waste water to which said hydrochloric acid has been added to a temperature in the range of more than 80Â° C. to the boiling point of said waste water to decompose said fluorophosphate compound into a hydrogen fluoride and a phosphoric acid, hydrogen chloride gas being generated during the decomposition of said fluorophosphate compound, directing the generated hydrogen chloride gas out of said treating vessel and into a condenser provided outside of said treating vessel, and adding a calcium compound to said waste water after said decomposition to fix and precipitate the fluorine and the phosphorus.