Author: Marisa
Difficulties in the treatment of three wastes in hot-dip galvanizing production lines: zinc fume collection, acid mist collection, rinse water treatment, and waste acid recovery.
I. Zinc fume collection
Currently, there are two types of zinc fume collection methods: closed type and open type. The former has a higher collection rate than the latter.
Closed type: fixed hood, mobile hood.
Open type: trough side double blowing type, trough side blowing and suction type, end blowing and end suction type.
II. Suppression and collection of acid mist
Acid mist suppression and isolation method: add acid mist inhibitor, cover the surface with plastic balls, and seal the acid tank.
Acid mist collection: side blowing and side suction, double-side suction.
III. Hydrochloric acid regeneration treatment
1. Oxidation roasting method, suitable for strip steel, not suitable for steel wire, steel pipe, structural parts galvanizing plant.
2. Negative pressure evaporation crystallization method.
3. Sulfuric acid replacement method.
IV. Rinse water treatment
The main sources of wastewater from hot-dip galvanizing enterprises are alkaline rinsing, pickling rinsing and post-plating cooling.
1. Use a rinse water-free process, but strengthen the iron removal management of the plating tank.
2. Membrane separation method can effectively treat zinc-containing chloride wastewater.
3. Electrodialysis method, low energy consumption for desalination, high cost performance, but low salt removal rate.