Method for treating low-concentration fluorine-containing wastewater

Abstract

The invention provides a treatment method of low-concentration fluorine-containing wastewater, which is used for subsequent treatment of an etching waste liquid treatment process, energy consumption cost is reduced, meanwhile, a high-concentration ammonium bifluoride solution is obtained through recovery, the resource utilization effect is improved, the fluorine content of discharged water is reduced, and environmental safety is guaranteed. The method comprises the following steps: introducing fluorine-containing treatment wastewater into a pre-reaction tank, and pre-treating the fluorine-containing treatment wastewater and a recovered hydrofluoric acid solution to obtain an ammonium bifluoride solution; then the wastewater is introduced into a microfiltration filter to be filtered, two-stage electrodialysis treatment is performed by adopting an electrodialysis device, first-stage fresh water and first-stage concentrated water are obtained through treatment of a first-stage electrodialysis device, the first-stage fresh water enters a fresh water storage tank, the first-stage concentrated water enters a second-stage electrodialysis device through a first-stage concentrated water tank to be treated, and second-stage fresh water and second-stage concentrated water are obtained; the second-stage fresh water is reused for the first-stage electrodialysis device, and the second-stage concentrated water enters a concentrated water storage tank.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater treatment, in particular to a treatment method for low-concentration fluorine-containing wastewater. Background technique [0002] The etching waste liquid produced by the semiconductor etching process mainly contains hydrofluoric acid and ammonium fluoride. The ammonium bifluoride product can be obtained through the waste liquid treatment process of evaporation and concentration, so as to realize the recycling of resources. However, in the process of evaporation and concentration, the evaporated The distillate will entrain a certain amount of fluorine and ammonia nitrogen, resulting in the treated wastewater formed after condensation containing ammonium fluoride with a mass fraction of about 0.5-5%, that is, the fluorine content is about 2500-26000mg / L, and the ammonia nitrogen content is about 2300~25000mg / L. If this kind of fluorine-containing treatment wastewater is discharged di...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the disadvantages that the fluorine content of the treated wastewater obtained by the existing etching waste liquid evaporation and concentration treatment process is not up to the standard, the direct discharge causes environmental pollution, and the waste water is reused in the waste liquid treatment process, which consumes a lot of energy. The present invention provides a low-concentration fluorine-containing The waste water treatment method is used for the subsequent treatment of the etching waste liquid treatment process. While reducing energy consumption costs, a high-concentration ammonium bifluoride solution is recovered to improve the resource utilization effect, reduce the fluorine content of the discharged water, and ensure environmental safety.

Images