How to Treat Aluminum Surface Wastewater


Release time:

2022-06-21

The wastewater produced by the surface treatment of aluminum profiles includes pretreated degreasing and neutralizing acid washing water, alkali washing water after alkali corrosion, pickling water after acid etching, pickling water after oxidation, and painting wastewater after coloring. The mixed waste water is acidic and contains organic substances such as surfactants and acrylic resins.

1. Key analysis of the source and type of aluminum surface wastewater

aluminum profile surface treatment The wastewater generated includes pretreated degreasing and neutralizing acid washing water, alkali washing water after alkali corrosion, and acid washing water after acid etching., Pickling water after oxidation, painting wastewater after coloring. The mixed waste water is acidic and contains organic substances such as surfactants and acrylic resins. The waste liquid includes waste sulfuric acid produced by degreasing neutralization, waste nitric acid and waste sulfuric acid produced by oxidation, waste liquid produced by coloring, waste acrylic liquid produced by electrophoretic painting, and waste liquid of Ni 2 + and F + produced by sealing waste.

2. Methods to reduce waste water and waste liquid discharge

Methods to reduce waste water and waste liquid include reasonable control of water control time and filling angle to reduce the amount of liquid carried in the water tank, and try to use two-stage and Three-stage countercurrent flushing to reduce water consumption. The washing water after acid etching and degreasing is used for washing after alkali etching, and the washing water after oxidation is used for washing for acid etching and degreasing. In addition, in order to reduce or avoid the discharge of wastewater and waste liquid tanks, the production line should design and use various recycling equipment, such as acid corrosion recycling equipment, alkali corrosion recycling equipment, anodized aluminum removal equipment, coloring liquid RO recycling equipment, Electrophoretic paint RO recycling equipment, the use of these recycling equipment can minimize the discharge of wastewater and waste liquid, and also minimize production costs.

3. The principle and method of aluminum profile surface treatment wastewater treatment

Aluminum profile surface treatment The wastewater produced is mainly acid and alkali wastewater, which contains a small amount of harmful anions and cations, such as Ni2 +, Sn2 + and F-. The treatment method is acid-base neutralization. The waste water is usually acidic, so it must be neutralized by adding alkali, and the pH should be adjusted to 7-8.5. At the same time, the cations Al3 +, Ni2 +, Sn2 + and Cr3 + all form hydroxide precipitates during neutralization. The neutralized and precipitated wastewater is pumped into the coagulation tank by a pump, and the dissolved polyamide flocculant and wastewater are coagulated by a quantitative pump at the same time, so that the coagulated wastewater enters the sedimentation tank. The settlement method includes inclined plate settlement and air floatation. Xiaobian believes that the centrifugal sedimentation method is more stable. After settling, the clear liquid overflows from the upper overflow and enters the drain or post-treatment tank. After the above treatment, the wastewater can reach the standard discharge.

If you want to reuse the wastewater, you can treat the wastewater through reverse osmosis equipment after coarse filtration to remove excess anions, cations and organic matter. At this time, the pH value of the water may be low, and the reuse standard can be reached after adjustment by anion exchange and cation exchange devices. The sludge produced by sedimentation is regularly discharged into the sludge tank, and after being treated by a flat filter press or a belt dehydrator, it becomes industrial waste residue and is sent to an industrial waste residue treatment plant.

The treatment of surface wastewater and waste liquid mainly adopts countercurrent washing, and the first stage adopts two-dimensional and three-stage treatment, which can effectively reduce water consumption. The whole process is more complicated. The zero discharge process of surface wastewater is realized, and the treatment of surface wastewater and waste liquid reflects the social responsibility of enterprises. The damage caused by surface wastewater to soil and water sources is irreversible. The state also imposes severe fines and strict investigations on companies that privately discharge such waste water.