Common problems of electroplating production line and treatment methods of electroplating wastewater reuse

[Participants’ questions] Electroplating production lineCommon problems and treatment methods of electroplating wastewater reuse?

[Answer] With the rapid development of the industry, the types and numbers of wastewater have increased rapidly, and the pollution of water bodies has become increasingly widespread and serious, threatening human health and safety. For the protection of the environment, the treatment of industrial wastewater is more important than the treatment of urban sewage. Although the treatment of industrial wastewater started as early as the end of the 19th century, and a large number of experimental studies and production practices have been carried out in the following half a century, but due to the complex composition and changeable nature of many industrial wastewater, there are still some technical problems that have not been completely resolved. , Electroplating wastewater is one of the important objects. Let’s analyze the problems that often occur in electroplating production lines:

The production process is backward

(2) Unclear separation of wastewater

(3) Water volume exceeds facility processing capacity

(4) Concentration of pollutants in wastewater is too high

(5) Generate new pollutants

The main sources of wastewater from electroplating and metal adding are degreasing water, cyanide-containing wastewater, and chromium-containing wastewater pickling solution. Pollutants are transferred to the rinse water through the metal rinsing process. The pickling process includes first immersing the metal (zinc or copper) in a strong acid to remove oxides on the surface, and then immersing it in a brightener containing strong chromic acid for brightening treatment. The wastewater contains a large amount of hydrochloric acid, zinc, copper and other heavy metal ions and organic brighteners, etc., which are relatively toxic, and some also contain carcinogenic, teratogenic, and mutagenic highly toxic substances, which are extremely harmful to humans. Therefore, the electroplating wastewater must be recycled and treated carefully to eliminate or reduce its environmental pollution. We can take the following measures:

1. Except for gold plating, cyanide-free electroplating must be used instead of cyanide electroplating.

2. Appropriate organic film processing devices are used for developing and washing equipment;

3. Use sodium persulfate instead of ammonium persulfate for coarsening;

4. Use high-purity raw materials.

5. Separate and single treatment of wastewater.

6. Cyanide wastewater, complex wastewater (copper precipitation and alkaline etching), organic wastewater, chemical nickel wastewater, etc. should be split for pretreatment;

7. Separation of complex wastewater from comprehensive wastewater, using separate reactions, precipitation and sludge dehydration;

8. Each stream of wastewater should be connected to the wastewater treatment station through pipelines as much as possible;

9. Change ground mixed flow to pipe diversion;

10, electroless plating nickel wastewater should be separately pretreated by oxidation;

11. Continuously carry out technical upgrades and change manual plating to automatic production line.

12. Improve the level of clean production, improve the rinsing process, and reduce waste water discharge, such as the use of multi-stage counter-current bleaching process;

13. Reuse the rinsing water by tank-side treatment to improve the utilization rate of waste water and reduce the amount of waste water discharge;

14. Improve the hanging method of hangers and plating parts, reduce the amount of liquid brought out, and reduce the concentration of rinsing water;

15. Add plating solution recovery tank on the production line;

16. The electroplating concentrated waste liquid produced by deplating or replacing the plating bath should not be discharged into the wastewater treatment station, and it should be collected separately and handed over to a qualified professional company for outbound treatment;

17. Improve the wastewater treatment process from primary treatment to secondary treatment;

18. Waste acid or waste lye can be used as water treatment chemicals for waste utilization.

The above content is organized based on the problems encountered by the students in their actual work for reference. If you have any problems, please communicate and correct them in time.