| 摘要 |
Treatment of plating effluents, including at least chromium plating effluent and, in plants having it, zinc plating effluent as well as effluents from plating copper, cadmium, or nickel, removing from these effluents the heavy metal ions. Hexavalent chromium ions are removed directly, without first reducing them to trivalent forms, by adding barium acetate. When other plating effluents are treated, the formed barium compounds are used as a coagulant for their hydroxides, which may be formed by mixing any of these other effluents with the formed barium compound and adjusting the pH to the value enabling precipitation of the hydroxides. Sulfuric acid may be used for this pH adjustment, thereby also precipitating out any remaining barium ions in solution.
|
