Automatic treatment system for waste acid liquid generated after metal pickling and process thereof

Abstract

The invention provides an automatic treatment system for waste acid liquid generated after metal pickling and a process thereof, and relates to the technical field of environmental protection and governance. The automatic treatment system comprises an oxidation reaction system, a physical separation system, an ion trapping system and a purification and regeneration system which are connected in sequence. The automatic treatment system has the advantages that the pickling waste acid liquid generated by metal pickling is treated, and dissolved metal ions in the waste acid liquid are recycled, wherein treatment is all performed through automation control over the whole process, thereby saving manpower for on-site monitoring and reducing the cost of human resources, and no secondary pollutionis caused in the whole operation process, so that the system is conducive to environmental protection and has important social, economic and ecological benefits.

Description

Technical field [0001] The invention relates to the technical field of environmental protection treatment, in particular to an automatic treatment system and a process for producing waste acid after metal pickling. Background technique [0002] Before electroplating, in order to achieve the removal of rust and oil stains on the surface of the plated parts, 20-25% hydrochloric acid solution is usually used as a cleaning agent, but as the pickling operation continues, 1kg of acid in the acid solution is consumed for every 1kg. With the continuous consumption of acid, the number of soluble metal chlorides increases. When the acid content in the acid solution drops to about 3%, the acid solution loses its pickling effect. This pickling liquid becomes a hazardous chemical or waste acid. Waste acid liquid contains hydrochloric acid, organic matter and dissolved metal ions. If it is discharged without treatment, it will not only cause serious pollution to the ecological environment, b...

AI Technical Summary

Problems solved by technology

[0004] The hydrochloric acid regeneration method mainly adopts the method of heating, depressurizing, evaporating, spraying and burning. Its system and process directly heat hydrochloric acid to recover hydrochloric acid and ferric chloride. Large investment, high operation and maintenance costs, serious equipment damage, generally unbearable for small and medium-sized enterprises

Therefore, most small and medium-sized enterprises generally adopt the lime neutralization method, expecting to neutralize the waste acid solution and then add water to dilute it to meet the discharge standard. The ions need to be at a pH of about 9-9.5 to precipitate completely, so there will be more metal ions remaining in the water in a dissolved state, even if diluted with water, it is difficult to discharge up to the standard; at the same time, the calcium salt formed after neutralization is mainly The amount of sediment is large and it is extremely difficult to further process, thus causing secondary pollution

Therefore, the lime neutralization method not only consumes a large amount of lime and fresh water, but also fails to meet environmental protection requirements, and also produces a large amount of waste residue to cause secondary pollution.

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