Smut remover, its manufacturing method and smut removal method using it

摘要

PROBLEM TO BE SOLVED: To provide a smut remover having a small environmental load by strongly removing smut generated in a steel material after pickling. SOLUTION: This is a smut remover composed of polyhydric phenol and alkali, having a pH of more than 12 and an oxidation-reduction potential of −250 mV or less, a method for producing the same, and a method for removing smut using the same. .. [Selection diagram] None