| 摘要 |
PURPOSE:To enhance the removal efficiency of mercury, by preliminarily removing a fine floated substance and colloidal mercury obstructing the removal of mercury from a mercury-containing waste solution before passing said waste solution through a resin. CONSTITUTION:An acid such as sulfuric acid or hydrochloric acid is added to the waste solution with pH14 or more from a Zn amalgam manufacturing process to adjust the pH thereof to 8-11 and a metal contained in said waste solution is precipitated, for example, by converting Zn to Zn(OH)2. Next, a high- molecular flocculant is added to the waste solution to grow flocs of the neutralized product of the contained metal and said flocs are subjected to solid-liquid separation to remove SS. An acid such as sulfuric acid or hydrochloric acid is added to the filtrate after solid-liquid separation to adjust the pH thereof to 5 or less to release CO3<2-> in the solution. Further, an oxidizing agent such as NaClO is added to the waste solution after the removal of CO3<2-> to perform stirring so as to oxidize colloidal mercury to Hg<2+> ion. When pH is low, pH of the treated waste solution is made weak acidic by an alkali agent and said waste solution is passed through a resin to lower Hg in waste water to a large extent from a waste water prescribing value.
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