METHOD OF TREATING ACID WASTE LIQUID CONTAINING ZINC AND IRON, AND TREATING AGENT

摘要

PROBLEM TO BE SOLVED: To provide a method of treating an acid waste liquid containing zinc and iron discharged in a hot dip galvanizing process efficiently with lowered sludge production quantity. SOLUTION: In the method of treating the acid waste water containing zinc and iron discharged from the hot dip galvanizing process, a liquid to be treated is mixed with an alkali aqueous solution having pH >=11 at >=50 deg.C to form a mixed liquid having >=50 deg.C and pH 6-11 to precipitate the dissolved zinc ion and iron ion as a hardly soluble material.