| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating cyan-containing waste water, in which even if the cyan-containing waste water contains a cyan compound, that is used for forming a complex together with a metal ion, and organic matter except a cyan ion, the cyan compound can be removed efficiently and the cyan concentration of the cyan-containing waste water can be lowered satisfactorily.SOLUTION: The method for treating cyan-containing waste water comprises steps of: adding copper salt and a reducer to the cyan-containing waste water; adding ferric salt to the resulting cyan-containing waste water; and adjusting the pH of the ferric salt-added cyan-containing waste water to 6-8. The amount of the ferric salt to be added is made equal to or larger than twice of a molar quantity of the cyan compound in the cyan-containing waste water and made equal to or smaller than seven times thereof. The amount of the copper salt to be added is 5-20 mol% of the amount of the ferric salt to be added. The amount of the reducer to be added is made equal to or larger than thrice of the molar equivalent to be required for reducing the copper salt and made equal to or smaller than fifteen times thereof. |
