| 摘要 |
PURPOSE:To provide a method of the purification of metal plating waste water, wherein to waste water containing EDTA, HCHO, Cu, etc. are added a mineral acid, an oxidizing agent, a ferrous salt and an alkali in this order so that organic contaminants in the waste water can be decomposed and removed with a higher elimination rate. CONSTITUTION:In order to decompose and remove organic contaminants with a higher elimination rate from a chemical copper plating solution, which dose not mean a copper electroplating solution containing cyanide compounds, for example a chemical copper plating waste solution containing EDTA, HCHO, Cu, etc., a mineral acid, such as sulfuric acid is added to the waste solution to adjust its pH value to 1 to 2, the resulting precipitate is removed, then the filtrate (if desired, this filtrate is subjected to electrolysis to separate off copper for recovery) is added with an oxidizing agent such as hydrogen peroxide, oxidizing agents containing chlorine or the like to be subjected to oxidizing treatment and then is added with a ferrous salt, thereafter is added with an alkali (NaOH) to adjust its pH value to between 4 and 10 so that precipitation will be resulted, and a gas containing oxygen is introduced into the thus treated solution to floculate the precipitate to be removed. |
