Three wastes and treatment measures of the hottest

2022-09-23
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Three wastes and treatment measures of electrophoretic coating

1.1 the wastewater and sludge of electrophoretic coating mainly come from pre washing drainage, degreasing and derusting sludge and the washing drainage after treatment, phosphating sludge and washing drainage after phosphating, and washing drainage after electrodeposition. The main components of wastewater or sludge from these processes are:

a. pre washing drainage: mainly physical impurities, such as oil, sediment, etc., pH ≥ 7

b, degreasing and derusting sludge: invalid pickling solution, corrosion inhibitor, surfactant and other additives, as well as fe2+, Fe2O3, oil stain, sediment and other impurities, pH 7

c, wash and drain water after oil and rust removal; Residual pickling solution and its additives, fe2+, ca2+, and other impurities, pH 7

d, phosphating sludge: invalid phosphating solution, containing Fe, Zn, Mn phosphate and ca2+, mg2+, po43-, no3- plasma, pH 7

e, washing and drainage after phosphating, which is divided into two parts

① tap water washing and drainage: residual phosphating solution and additives and computer screen control and display experimental force and experimental curve acrobatics, pH 7

② pure water washing and drainage: there are very few impurities, mainly C, which pushes the external but not like wood and treated wood wall insulation materials to the top of the storm, a2+, mg2+, etc., pH ≤ 7

f, washing water after electrodeposition: a small amount of paint particles, pH ≤ 7

1.2 waste gas is mainly acid mist and toxic solvents. Source:

A. some volatile acid mist will be emitted into the atmosphere from the pickling solution used in the derusting process, and the amount of emission will vary depending on the pickling solution products used

b. When the wet film after electrodeposition is dried and solidified, the residual organic additives will be released from the film and pollute the atmosphere

According to the analysis, the seriousness of the "three wastes" of electrophoretic coating lies not only in the discharge of sewage (a small and medium-sized coating line consumes about 7t/h), but also in the pH value of the wastewater and the impurities (composition and content) contained, which exceed the allowable range of environmental protection in many aspects. According to the properties (acidity and alkalinity), components and causes of formation of wastewater, waste gas and sludge in electrophoretic coating, the treatment of "three wastes" can be started from the following aspects:

2.1 some wastewater caused by physical impurities (such as oil and sediment in pre washing drainage) can be treated by natural sedimentation method and oil-water separation method, and then discharged after removing oil and silt

2.2 in the treatment of waste gas, it is mainly to introduce new materials, new products and new technologies to minimize the emission of waste gas, mainly including:

a. for the material and surface state of precoated parts, introduce efficient and environmental friendly cleaning agents, and select some cleaning agents that are energy-saving and less volatile in acid mist on the premise of ensuring the cleaning effect

b, developing and purchasing low solvent coatings is also a common goal pursued by the coating industry and the coating industry

c. According to the material and surface state of the precoated parts, select some surface treatment methods and processes with strong pertinence, good cleaning effect and less acid mist, such as A3 cold-rolled plates with oil pollution as the main part, rust free or slightly rusty, instruments and meters with high finish, etc. if the ultrasonic comprehensive surface treatment technology is adopted, it is better than the general acid washing method (or two in one method), because the ultrasonic method is used to treat this kind of workpiece, It can not only obtain better treatment quality and economic effect, but also be safe. With less acid mist, Changzhou No.6 element material technology Co., Ltd. is a national high-tech enterprise specializing in the research, development, production and sales of graphene powder, which has less environmental pollution

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