At present, the method to treat the waste liquid of pickling stainless steel containing HF at home and abroad is chemical method, in which F- ions are separated out in some salts and directly discharged by means of acid and alkali neutralization. Domestic large and small enterprises almost all use this method, obviously this treatment method will cause serious pollution to the environment. Based on the principle of electrolysis, this project conducts electrolysis treatment on the waste liquid, selects the appropriate electrode and adds the active agent to the waste liquid, and finally achieves the precipitation of only metal ions on the cathode in the acidic waste liquid without the precipitation of H+ reduction.

In this way, if acid is further added to the waste liquid after treatment, the cleaning liquid will continue to be used, solving the problem of discharge pollution. Because of the high potential of F- ion oxidation precipitation, there is no problem of F- oxidation precipitation consumption in the electrolytic process, and it always exists in the waste liquid.