Pickling and phosphating sewage treatment

Pickling refers to the use of pickling solutions such as hydrochloric acid, sulfuric acid, etc. to wash off the oxide layer and dust and other substances on the workpiece, which has the effect of cleaning the surface.

A large amount of wastewater is generated in the pickling and phosphating process, and the sewage mainly comes from the pickling sewage, rinsing water and part of the phosphating sewage of motor parts, containing pollutants such as zinc ions, iron ions, monohydrogen phosphate ions and dihydrogen phosphate ions, and the sewage is acidic, and the treatment of this kind of sewage focuses on removing metal ions and neutralizing acidic substances. Through the screening of chemicals and processes, it was determined that the physicochemical method, that is, the conditioning-coagulation-precipitation process was used for treatment.

Process principle:

The use of lime to treat sewage can not only reduce the acidity of sewage, but also precipitate calcium phosphate and promote the concentration of phosphorus ions to be controlled to a certain extent. Moreover, the lime treatment process can also reduce the concentration of other heavy metals, and the treatment process has certain economic and environmental protection characteristics.