Recovery of Chromic Acid Solution:
Passivation solutions containing hexavalent chromium are not allowed to be discharged. Currently, cationic exchange resins are commonly used to first recover the hexavalent chromium. Subsequently, reducing agents such as ferrous sulfate are employed to reduce the hexavalent chromium, followed by neutralization with lime milk and precipitation separation. After separation, the supernatant can be discharged.
Treatment of Waste Phosphating Solution:
The treatment of waste phosphating solutions generally adopts the method of neutralization and precipitation with lime milk.
