Hydrochloric acid - a method for recovering the hydrochloric acid and hydrofluoric acid, respectively from hydrofluoric acid mixed acid waste

摘要

PROBLEM TO BE SOLVED: To provide a method for separately recovering a hydrochloric acid-based mixed acid and a hydrofluoric acid-based mixed acid from a mixed acid waste liquid containing hydrochloric acid and hydrofluoric acid by simple distillation operations at a low cost.;SOLUTION: The method for separately recovering hydrochloric acid and hydrofluoric acid from a hydrochloric acid-hydrofluoric acid-based mixed acid waste liquid includes: a first distillation step of distilling a mixed acid liquid containing hydrochloric acid and hydrofluoric acid at a distillation rate of 20-89 mass% from a mixed acid waste liquid containing hydrochloric acid and hydrofluoric acid to obtain a first distillate; a second distillation step of dissolving lithium nitrate in the first distillate and distilling a mixed acid liquid with an increased composition ratio of hydrochloric acid from the resulting solution to obtain a second distillate; and a third distillation step of distilling a mixed acid liquid with an increased composition ratio of hydrofluoric acid from a distillation residual liquid obtained at the first distillation step to obtain a third distillate.;COPYRIGHT: (C)2011,JPO&INPIT