The invention provides a method for treating acid-washing
wastewater and metallic ions in iron and steel industry, which comprises steps as follows: acid-washing
wastewater naturally flows into a water collecting well and enters a preneutralization filter chamber under the elevation action of a pump, the preneutralization filter chamber is provided with 10-200mm limestone which is in a graded distribution mode, and after the acid-washing
wastewater is preneutralized by the limestone, the pH value of the
effluent water is controlled at 5-6, wherein the method provided by the invention greatly lowers the chemical expenses and
operating cost as compared with the conventional method of directly adding an alkali solution; the acid-washing wastewater, which is subjected to initial pH value regulation, naturally flows into an
oil separation regulating chamber, so that iron ions in the wastewater react with the alkali solution to form a
precipitation mixture of
ferric hydroxide,
zinc hydroxide and the like; and the wastewater is elevated into a membrane
solid-liquid separator to complete
solid-liquid separation, so that the wastewater can be discharged after reaching the standard. The invention thoroughly solves the problems that the precipitate can not easily settle, the iron can not be easily removed, and the iron ions are dissolved out. The invention has the advantages of simple technique, high economy, low requirements for technical levels of workers, and high
controllability, is reliable to operate, and has wide market prospects.