| abstract |
PURPOSE:To regenerate and recover all fluorinated products and alkaline component in a waste liquid as reutilizable alkali and gaseous HF by using an ion exchange membrane electrodialyzing device. CONSTITUTION:Alkaline waste liquid of fluorinated products contg. metal ions and oil is neutralized by the addn. of hydrofluoric acid, and the oil is removed. Then, the metal ions are removed by adsorbing to a chelate resin, then, the waste liquid is separated to alkali and HF in an ion exchange membrane electrodialyzing device constructed by a combination of a bipolar membrane B, an anion exchange resin A, and a cation exchange resin C, and the acid and the alkali are regenerated and recovered. Thus, the fluorinated products and the alkaline component in the waste liquid are all regenerated and recovered as reutilizable alkali and soln. of gaseous HF. In this case, a part of the recovered HF is used for the HF to be added to the waste liquid. |