Process principles for steel pipe factory electroplating wastewater treatment: electroplating wastewater from the electroplating process plating, the bath filtration, waste bath emissions. Wastewater containing mainly acid and alkali metal ions, cyanide, ammonia and various additives (such as brighteners, detergents, surfactants, etc.). Many species of heavy metals in waste water treatment, and can be divided into the following two categories:

(1) the solubility of heavy metals into an insoluble or poorly soluble metal compounds, thereby removing it from the water. There hydroxide precipitation method commonly used method of sulfide precipitation, electrolysis, ferrite, ion flotation, membrane electrolysis and so on.

(2) without changing the chemical form of heavy metal concentration and separation situations, there is a method commonly used in reverse osmosis, electrodialysis, ion exchange, and concentrated by evaporation method.

For example: wastewater containing cyanide and chromium-containing wastewater should be strictly shunt, steel plant for wastewater containing cyanide oxidation of collected through NaCLO a cyanate, and then the two oxidized to CO2 and N2 and removed. Chromium waste and mixed waste water containing in FeSO4 as the reducing agent, the Cr6 + is reduced to Cr3 +, adding a base to Cr3 + and other heavy metal ions (Mn + indicates) there were precipitation, generates M (OH) n · Fe (OH) 3, and then by through air, heating, aging and other processes that occur in wastewater various hydroxide complex solid phase chemistry reaction to form ferrite, precipitated the effluent discharge standards. Sinotrans sludge landfill emissions or recovery of useful substances.