| 摘要 |
PURPOSE:To effectively remove ions from an iron ion-contg. liquid by bringing the iron ion-contg. liquid and an extracting agent contg. at least one kind of primary and quaternary amines into contact with each other and bringing the extracting agent into contact with a back extracting agent having specific pH and contg. a reducing agent. CONSTITUTION:The iron ion-contg. liquid such as electrogalvanizing bath liquid and the extracting agent contg. at least one kind among the primary and quaternary amines are brought into contact with each other via a solid film 2 consisting of a polytetrafluoroethylene, etc., in an extracting device 3. The extracting agent is then brought into contact with the back extracting agent having <=3.5pH and contg. the reducing agent (e.g., dithionite) to back extract the iron ions. As a result, the iron ions in the iron ion-contg. liquid is efficiently removed and the iron ions are back extracted with high back extraction efficiency. The extracting agent can be, therefore, cyclically used. The amt. of the waste liquid to be treated is extremely small. Since the accumulation of the SS in the extracting agent is prevented, the efficient extraction is continuously executed.
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