Four Points Should Be Paid Attention To in The Recovery Of Square Rectangular Tube Acid Solution

Rectangular tubes need to be pickled during surface treatment such as electroplating. At present, the pickling solution used is transitioned from a single acid solution to a mixed acid solution and a composite acid solution. Single-acid waste acid liquid has always been a difficult problem for environmental protection, and the treatment of complex mixed acid and compound acid is even more difficult. When dealing with acid recovery, we should pay attention to the following four points:

(1) Whereabouts of regeneration acid

Since the acid recovery technology has been used in recent years, many design units have not designed regenerated acid recovery devices in the square tube production process. How to digest the residual acid in the waste pickling liquid after recovery, especially the whereabouts of various mixed acids is the first issue that enterprises must consider.

(2) Characteristics of various mixed acid waste pickling solutions

Environmental treatment usually adopts an alkali neutralization method for a waste acid solution to change the pH value of the solution to achieve neutrality. The disadvantages of using milk of lime to treat ordinary waste pickling liquid are not easy to appear, and there are no other technical problems except a waste of cost. However, many kinds of mixed acid waste liquids are different. The pollution of single acid waste liquid is only PH and Fe, while many kinds of mixed acid waste pickling liquids have F, P, NOx anions and chromium, nickel, zinc, etc. in addition to PH and Fe metal ions. For special ions, some pre-processing equipment needs to be added to the production process of square rectangular tubes.

(3) Wastewater treatment

Some companies believe that as long as the pH value of the waste pickling solution is neutral, it can replace sewage treatment, and some companies require comprehensive treatment by mixing degreasing wastewater, waste acid solution, flushing wastewater, and emulsion together. These treatment processes are not feasible. The acid recovery technology and equipment are only a link in the treatment process of industrial wastewater produced by square and rectangular pipes, and cannot replace the entire enterprise wastewater treatment.

(4) Characteristics of single-acid waste pickling solution for metal products

The pickling waste liquid of metal products has a single component, which is mainly the material of the metal product itself and the added elements of the material. Therefore, the salt composition in the waste liquid is not too complicated, most of the metal ions are divalent ions, the "effect" of separation is obvious, and no more pretreatment equipment is needed.