Aluminum surface treatment wastewater treatment technology

Introduction: Aluminum surface treatment of water, produce more waste water, harmful substances in the wastewater discharge. If not dealt with, it will pollute the environment. At the same time with China's tax on sewage discharge, but also increase the cost and burden on enterprises. Therefore, from the corporate social responsibility and effectiveness of both considerations, the implementation of wastewater treatment is necessary and necessary. The author summarizes many years of aluminum surface treatment and wastewater treatment technology research and management experience, put forward a set of practical wastewater treatment and reuse programs for peer reference.

1, aluminum surface treatment of wastewater sources and types:

A: The aluminum surface treatment of wastewater pre-treatment degreasing and acid washing water, caustic alkali washing water after acid etching acid washing water, acidic water washing after oxidation, after coloring containing Ni2 + Sn2 +, acidic washing water, electrophoretic paint ion exchange device generated waste acid, waste alkali and a small amount of electrophoretic paint wastewater. The mixed wastewater is acidic and contains cations such as Al3 +, Ni2 +, Sn2 +, Sn4 +, Na +, and Cr3 +, as well as anions such as SO42-, F-, NO3-, Cl-, AlO2- and Ac- and surfactants and acrylic acid Resin and other organic matter. The waste liquid is defatted and neutralized to generate waste sulfuric acid, waste nitric acid and waste sulfuric acid produced by oxidation, waste liquor generated by coloring, waste acrylic acid liquid produced by electrophoretic painting, and the waste liquid containing Ni2 +, F-

2, to reduce waste water and waste emissions approach:

A: The method of reducing waste water and waste liquid has reasonable control of water control time and control the loading angle to reduce the amount of bath liquid, try to use two level three countercurrent rinsing to reduce water consumption. After acid etching and degreasing water washing for alkali corrosion after washing, oxidation after washing water for acid etching and degreasing after washing. In addition, in order to reduce or avoid the discharge of waste water and waste liquid, the production line should design and use various recovery devices such as acid recovery device, alkali recovery device, anodized aluminum removal device, coloring solution RO recovery device, electrophoretic paint RO Recycling plant, the use of these recycling devices can be the amount of waste water and waste emissions to minimize, but also to minimize the production costs.

3, aluminum surface treatment wastewater treatment principles and methods:

A: Aluminum surface treatment of waste water, mainly acid-base wastewater, containing a small amount of harmful ions such as Ni2 +, Sn2 +, F-, the treatment is acid and alkali neutralization. Waste water is generally acidic, must be added alkali and adjust PH value to about 7 to 8.5. At the same time in the process of neutralization of the cation Al3 +, Ni2 +, Sn2 +, Cr3 +, etc. are formed hydroxide precipitate. After neutralization and precipitation of waste water into the coalescing tank pump, while using a quantitative pump into the dissolved polyamide flocculant and wastewater coagulation, coalescence of waste water into the sedimentation tank, the precipitation of a precipitation ramp method, flotation Method, centrifugal precipitation method, etc., I believe that the use of centrifugal precipitation method is relatively stable, after precipitation, the supernatant from the overflow overflow into the discharge tank or re-treatment of the reservoir. After the above-mentioned treatment of wastewater can discharge standards, if you want to reuse the wastewater, the wastewater can be rough after filtration into the RO device for processing, remove excess yin and yang, organic matter, the water PH value may be low , Can be adjusted by the anion exchange device to achieve reuse standards. Sludge produced by the sedimentation is periodically discharged into the sludge tank and processed into plate-shaped cake-pressing machine or belt-type dehydrator to become industrial waste, which is sent to the industrial waste treatment plant.