| 摘要 |
PURPOSE:To clean and remove sludge produced due to scale and cleaning, by cleaning in a hydrogen peroxide solution after acid-cleaning. CONSTITUTION:Acid liquid (e.g., hydrochloric acid, sulfuric acid, citric acid, etc.) having a density of approximately 1 to 10 percent is poured into a system, and is circulated in such a condition as heats at a normal temperature or at a temperature below a boiling point. Afterwards, acid liquid is drained, and acid liquid and non- soluble part being dispersed are drained out of the system, and then a washing-in- water is performed. After washing in water, remaining acid is neutralized by performing a neutralization corrosion-proof treatment, and a corrosion-proof film is provided at an activated metal surface as a result of washing in acid. After washing in water agains, about 0.1 to 5 percent hydrogen peroxide solution is poured into a system where sludges are piled in heaps, and the sludges in heaps will be disolved due to the hydrogen peroxide foaming action. |
