METHOD FOR RECOVERING HYDROCHLORIC ACID FROM WASTE IRON-HYDROCHLORIC ACID TREATMENT LIQUID

PROBLEM TO BE SOLVED: To recover high-concentration hydrochloric acid from a waste iron-hydrochloric acid treatment liquid at a low cost. SOLUTION: The waste iron-hydrochloric acid treatment liquid containing ferric chloride is continuously or intermittently poured into a waste iron-hydrochloric acid treatment liquid which contains at least 65 mass% ferric chloride and 7-28 mass% water and from which hydrochloric acid is being extracted at 125-150°C under a reduced pressure; thereby, this waste iron-hydrochloric acid treatment liquid after the above-described pouring is caused to retain its temperature and its above-described ferric chloride content and water content. Thus, ferric chloride is hydrolyzed, and iron oxide and hydrochloric acid of a high concentration of at least 20 mass% are continuously extracted and recovered. COPYRIGHT: (C)2004,JPO