| 摘要 |
PURPOSE:To recover valuable metals such as Cu, Ni or Zn, by allowing acidic waste water containing valuable metal ions such as Cu, Ni, or Zn ions along with Al and Fe components to pass a limestone layer to remove Al and Fe components as a precipitate. CONSTITUTION:Acidic waste water containing valuable metal ions such as Cu, Ni or Zn ions along with Al an Fe components is passed through a limestone layer with a particle size of about 1-20cm. By this treatment, the pH of acidic waste water is stably held to about 5, and Al and Fe ions form a precipitate in a hydroxide form but Cu, Ni and Zn can be allowed to remain in waste water as an ion form. Subsequently, a chelate agent such as alkali dithiocarbamate or a salt thereof is added to waste water to effectively recover valuable metals such as Cu, Ni or Zn.
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