METHOD FOR RECOVERING HYDROFLUORIC ACID

摘要

A method for recovering hydrofluoric acid is provided to prevent scales from being generated in an evaporator and suppress the decrease of electrothermal efficiency, thereby recovering refined hydrofluoric acid having fewer impurities at a high yield. An evaporator(1) heats waste hydrofluoric acid to recover crude hydrofluoric acid of a vapor state, and separate enriched waste. A first distillation column(21) distills the crude hydrofluoric acid to separate into the enriched waste having a concentration higher than the crude hydrofluoric acid and recovery water. A second distillation column(22) distills the enriched waste to separate into refined hydrofluoric acid and waste. Enough sulfuric acid is added into the waste hydrofluoric acid in the evaporator, thereby suppressing metal components from being extracted.