| 摘要 |
PURPOSE:To obtain a treating soln. for rapidly and efficiently dissolving and removing iron oxide on a metallic surface by adding a specified amount of an org. acid salt of a reductive bivalent metal to a treating soln. contg. a chelating agent and by keeping the pH of the soln. at a specified value. CONSTITUTION:When iron oxide produced on a metallic surface by hot rolling is dissolved and removed, a soln. prepd. by adding 0.05X10<-3>-1.0X10<-3>mol/l org. acid salt of a reductive bivalent metal to a treating soln. contg. a chelating agent is used and the pH of the soln. is kept at 4.0-5.0 during dissolving operation. Then concn. of the chelating agent in the treating soln., is about 1X10<-3>-1X10<-1>mol/l (expressed in terms of a free chelating about) and the temp. of the treating soln. is about 40-90 deg.C. EDTA, nitrilotriacetic acid or the like is used as the chelating agent and iron (II) oxalate, iron (II) fumarate, iron (II) tartrate or the like as the org. acid salt. |
