TREATMENT OF STEEL PICKLING WASTE

PURPOSE:To conduct well and economically the separation by precipitation of steel pickling waste utilizing effectively electric furnace slug by neutralizing the waste liquid at least with the slug. CONSTITUTION:Acid pickling with hydrochloric acid and sulfuric acid is conducted for cleaning the surface of a steel material by removing oxidized scale, etc., sticking on the surface of a heat treated steel material. Electric furnace slug, preferably reduced slug, containing magnesium, iron, aluminum, etc., besides an equivalent amount of calcium is used as a neutralizing agent for neutralizing waste liquid after acid pickling. Lime slurry is preferably used as a neutralizing agent in combination with the electric furnace slug. The waste liquid, after being neutralized to pH4-5 with the electric furnace slug, is completely neutralized with the lime slurry. In this way, the separation by precipitation of the pickling waste can be conducted promptly and economically.