Method for increasing fluosilicic acid recovered from wet process phosphoric acid production

摘要

A method is disclosed for increasing the fluosilicic acid (FSA) recovered from a wet process phosphoric acid manufacturing process. The filtrate obtained by washing a filter cake is pumped to a stripper and reacted with H2SO4 to converting the dissolved FSA to gaseous SiF4. A defoamer is added to the acid-filtrate mixture to reduce the foam produced by the reaction and increase the amount of gaseous SiF4 recovered from the reaction. The gaseous SiF4 is recovered from the acid-filtrate reaction mixture and converted to FSA for commercial use.