METHOD FOR RECOVERING MIXED ACID WITH INCREASED HYDROCHLORIC ACID CONCENTRATION FROM HYDROCHLORIC ACID-HYDROFLUORIC ACID-BASED MIXED ACID WASTE LIQUID

摘要

PROBLEM TO BE SOLVED: To provide a method for recovering a mixed acid with increased hydrochloric acid concentration from a mixed acid waste liquid containing hydrochloric acid and hydrofluoric acid by a simple distillation operation at a low cost.SOLUTION: At least one metal salt selected from the group consisting of metal salts of nitric acid and metal chlorides is dissolved in a mixed acid waste liquid containing hydrochloric acid and hydrofluoric acid and distillation is carried out, whereby a mixed acid with the increased hydrochloric acid concentration is distilled and recovered.