Electrophoretic paint wastewater treatment device

Abstract

The utility model relates to an electrophoretic paint wastewater treatment device which comprises an electrophoretic paint wastewater storage tank, a demulsification tank, a first sedimentation tank, a first filter press, a wastewater fine particulate matter separation device, an oxidation alkalization flocculation tank, a second sedimentation tank, a second filter press and a wastewater discharge device which are connected in sequence, the electrophoretic paint wastewater treatment device further comprises a first sludge receiving tank connected with the first filter press and a second sludge receiving tank connected with the second filter press.

Description

Technical Field

[0001] The utility model relates to a device and equipment for treating waste liquid in industrial production, and also relates to a process and method for treating the waste liquid. More specifically, the utility model relates to a device for treating electrophoretic paint waste water and a process for treating electrophoretic paint waste water. Background Art

[0002] Since the development and industrial application of electrophoretic coating technology in the middle of the last century, its excellent properties, water-based environmental protection, high corrosion resistance, high degree of automation and other advantages have made it widely used in the automotive industry, motorcycle industry, household appliances, instrumentation, military industry, building materials and other industries. It has gradually replaced conventional surface coating technology and has become one of the most important coating technologies in the world today.

[0003] However, with the rapid economic development in recent years, the selection of components for electrophoretic paint often includes components of expensive metals. For example, in the coating industry of high-end automobiles, there is often a demand for chrome plating, nickel plating or other precious metal plating on the surface of automobiles to enhance the value and grade of the paint itself. Therefore, during the coating process, the electrophoretic paint wastewater collected is likely to be mixed with a large amount of metal particles. During the wastewater treatment process, if the precious metal particles are mixed with other sludge components, in the subsequent metal recovery application, a large amount of concentrated acid and alkali will have to be used again to salt or ionize the metal particles. Such treatment is not conducive to environmental protection, nor is it conducive to the recovery and reuse of high-value metal components.

[0004] In addition, in some application scenarios, the use of expensive flocculants is required. In the treatment of large amounts of wastewater, how to use expensive flocculants efficiently and accurately is also one of the problems to be solved.

[0005] There are many patent documents and R&D teams that have studied and reported on the treatment of electrophoretic wastewater. For example, China's invention patent CN107265787A involves a process for treating automobile coating wastewater and an automobile coating wastewater treatment system, which uses pretreatment, coagulation reaction, precipitation removal, hydrolysis acidification and molecular decomposition to treat automobile coating wastewater. The pretreatment process can degrease and precipitate the wastewater; then the pretreated wastewater is coagulated with an alkalizer, and the precipitate is removed. The hydrolysis acidification step can convert high-molecular organic matter into small-molecular organic matter, and finally the hydrolyzed acidified wastewater is added to a biological filter tank, and the small-molecular organic matter is decomposed by a biodegradation method. This treatment method relies on the decomposition of microorganisms, has poor controllability and is costly. At the same time, similar R&D and technology do not make special treatment, separation and reuse of precious metal particles in electrophoretic paint wastewater in the high-end automobile industry. Utility Model Content

[0006] The utility model improves one or more of the above needs and deficiencies. The utility model is an electrophoretic paint wastewater treatment device, which includes an electrophoretic paint wastewater storage tank, a demulsification tank, a first sedimentation tank, a first filter press, a wastewater fine particle separation device, an oxidation alkalization flocculation tank, a second sedimentation tank, a second filter press, and a wastewater discharge device connected in sequence. The electrophoretic paint wastewater treatment device also includes a first sludge receiving tank connected to the first filter press and a second sludge receiving tank connected to the second filter press; and

[0007] The first filter press comprises a filter press assembly, and the pore size of the filter cloth in the filter press assembly is between 0.50 mm and 0.90 mm; the second filter press comprises a filter press assembly, and the pore size of the filter cloth in the filter press assembly of the second filter press is between 0.05 mm and 0.30 mm.

[0008] In an optional technical solution, the wastewater fine particle separation device includes:

[0009] A pump for conveying wastewater containing fine particulate impurities transmitted from a pipeline of a first filter press at an upper stage;

[0010] A fine particle collection device, comprising a water storage tank for storing wastewater, a metal particle separation mechanism partially immersed in the water storage tank, and a metal particle recovery mechanism; and

[0011] The metal particle separation mechanism comprises a plurality of cathode electrode plates disposed in the water storage tank, a plurality of submerged rollers disposed between the cathode electrode plates, and a plurality of suspended rollers disposed above the plurality of cathode electrode plates; wherein the plurality of submerged rollers are submerged in the filtrate of the water storage tank;

[0012] The device also includes an electric motor disposed above the suspended roller, a driving roller driven by the electric motor, and a driven roller;

[0013] an endless steel belt, the endless steel belt being wound around the driving roller, the driven roller, the plurality of submerged rollers, and the plurality of suspended rollers;

[0014] A direct current power supply, one end of which applies a negative voltage to the cathode electrode plate and a positive voltage to the endless steel belt;

[0015] A metal particle recovery mechanism comprises a recovery box and a stripping portion above the recovery box, wherein the stripping portion is closely attached to the surface of the endless steel belt and is fixed.

[0016] In an optional technical solution, the pore size of the filter cloth of the first filter press at the water inlet is 0.80 mm to 0.85 mm, and the pore size of the filter cloth at the filtrate outlet side is controlled to be 0.50 mm to 0.55 mm; and

[0017] The pore size of the filter cloth of the second filter press on the side where the filtrate enters is 0.15mm to 0.20mm, and the pore size of the filter cloth on the side where the filtrate flows out is 0.06mm to 0.08mm.

[0018] In a further optional technical solution, the first filter press comprises:

[0019] Filter press components;

[0020] An inclined guide plate, the inclined guide plate is located below the filter press assembly and receives filter press mud cake from the filter press assembly;

[0021] a first motor connected to the inclined guide plate and used to drive the transmission of the inclined guide plate;

[0022] The first filter press further comprises a cutting device, a screw, a connecting rod, and a second motor, wherein the cutting device is in a square grid shape in the horizontal direction;

[0023] The connecting rod is threadedly connected to the screw rod, and the screw rod is driven to rotate by the second motor, so that the screw rod drives the connecting rod to move horizontally above the cutting device when it rotates; and

[0024] The connecting rod is connected with a pressing roller, which rolls the mud cake on the cutting device so that the mud cake is divided by the cutting device in the shape of a square grid.

[0025] In a further optional technical solution, the first filter press further includes:

[0026] A storage bin, the storage bin is located below the cutting device; a conveying pipe is fixed at the lower end of the storage bin, a third motor is fixed at one end of the conveying pipe, wherein the third motor drives the spiral blade in the conveying pipe to rotate, so as to convey the divided mud cake inside the conveying pipe;

[0027] A liquid collecting tank is arranged below the filter press assembly to collect the liquid after filter pressing, wherein a spiral stirring paddle is also arranged in the liquid collecting tank.

[0028] In a further optional technical solution, the recovery box is arranged below the portion of the endless steel belt that is not immersed in the water storage tank.

[0029] In a further optional technical solution, the plurality of cathode electrode plates are arranged on both sides of each immersion roller.

[0030] In the following, the technical solutions and advantages of the present utility model will be explained and illustrated in more detail in combination with the specific implementation methods. It should be understood that the contents presented in the specification and the specific implementation methods are only for the purpose of more clearly illustrating the technical solutions and advantages of the present utility model, and do not limit the protection scope of the present utility model. Those skilled in the art can obtain the changed technical solutions based on the disclosed contents of the specification for various reasonable transformations. As long as they do not deviate from the spirit of the present utility model, the various changed technical solutions should be understood to be included in the protection scope of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the specific embodiments of the present application, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure.

[0032] Figure 1 It is a schematic diagram of the connection relationship of various parts of the electrophoretic paint wastewater treatment system (device) of the utility model;

[0033] Figure 2 It is a cross-sectional schematic diagram of the filter press equipment used in the implementation scheme of the utility model;

[0034] Figure 3 Schematic diagram of the cross section of the fine particle collection device used in the embodiment of the utility model.

[0035] 1- storage tank for electrophoretic paint wastewater; 2- demulsification tank; 3- first sedimentation tank; 4- first filter press;

[0036] 5-wastewater fine particle separation device; 6-oxidation alkalization flocculation tank; 7-second sedimentation tank; 8-second filter press; 9-wastewater discharge device; 10-first sludge receiving tank; 11-second sludge receiving tank;

[0037] 401 - filter press assembly; 402 - inclined guide plate; 403 - first motor; 404 - cutting device;

[0038] 405-screw rod; 406-connecting rod; 407-second motor; 408-storage bin; 409-transport pipe;

[0039] 410 - third motor; 411 - liquid collecting tank;

[0040] 501-pump; 502-fine particle collection device; 503-water storage tank; 504-metal particle separation mechanism; 505-metal particle recovery mechanism; 506-cathode electrode plate; 507-immersion roller; 508-suspended roller; 509-electric motor; 510-driving roller; 511-driven roller; 512-annular steel belt; 513-discharge outlet; 514-recovery box; 515-peeling part; 516-DC power supply. DETAILED DESCRIPTION

[0041] The present invention is described in more detail below to facilitate understanding of the present invention.

[0042] Before describing the specific implementation scheme, it should be noted that those skilled in the art can select appropriate raw materials according to the enlightenment and teaching of the present disclosure, and use relevant testing equipment to perform relevant tests and obtain corresponding results. For raw materials without specific manufacturers or pathways, those skilled in the art can select raw materials that meet corresponding requirements as reaction starting materials according to the disclosure and requirements of this specification. The reaction raw materials of the process part compounds are derived from the initial products synthesized in the preamble step of the present utility model, which can also be understood according to the present disclosure.

[0043] This embodiment will describe the treatment equipment and process of electrophoretic paint wastewater, which involves important equipment and devices used in the relevant technology. For equipment or devices that can be obtained in the existing technology, or equipment and devices that those skilled in the art know should be used, in order to omit unnecessary space in the specification, the specific description will be omitted. Those skilled in the art can obtain the specific process or equipment for the corresponding implementation based on the description of the utility model specification and the relevant professional and technical knowledge in the field.

[0044] The electrophoretic paint wastewater used in this embodiment and the equipment operation is from FAW-Volkswagen Shenyang Audi A6L TM In the metallic paint electrophoretic coating workshop, the initial wastewater contains some metallic paint metal dust and particles (mainly Cr and a small amount of Ni, and its oxide particles), and the initial COD measurement value is about 9000 mg / L.

[0045] Example 1

[0046] This embodiment describes the electrophoretic paint wastewater treatment device (system) preferably used in the present invention, which can be applied to execute the corresponding electrophoretic paint wastewater treatment process in a typical device structure.

[0047] Combination Figure 1It can be seen that the electrophoretic paint wastewater treatment system 1 includes an electrophoretic paint wastewater storage tank 1, a demulsification tank 2, a first sedimentation tank 3, a first filter press 4, a wastewater fine particle separation device 5, an oxidation alkalization flocculation tank 6, a second sedimentation tank 7, a second filter press 8, and a wastewater discharge device 9, which are connected in sequence. The electrophoretic paint wastewater treatment system also includes a first sludge receiving tank 10 connected to the first filter press 4 and a second sludge receiving tank 11 connected to the second filter press 8.

[0048] The following is a more detailed description of the structure of the first filter press 4 used in the present invention. The present invention preferably adopts the filter press structure described below, but it is known to those skilled in the art that other filter press devices with similar structures can also be used within the technical scope known to those skilled in the art, as long as they can meet the key points of the present invention.

[0049] refer to Figure 2 The first filter press 4 includes a filter press assembly 401 and an inclined guide plate 402, wherein the inclined guide plate 402 is located below the filter press assembly 401 and receives the mud cake of the filter press sludge from the filter press assembly 401 (combining with Example 1, it can be the first sludge in step 3, and according to the working conditions, the mud cake can be transferred by transportation or other means). The first motor 403 is connected to the inclined guide plate 402 and is used to drive the transmission of the inclined guide plate 402. The equipment also includes a cutting device 404, a screw 405, a connecting rod 406, and a second motor 407. When the inclined guide plate 402 transfers the mud cake, the mud cake will fall on the upper end of the cutting device 404, and the screw 405 will be driven to rotate by starting the second motor 407. The connecting rod 406 is threadedly connected to the screw 405, so that when the screw 405 rotates, it drives the connecting rod 406 to move horizontally on the upper end of the cutting device 404. During the movement of the connecting rod 406, a pair of pressure rollers (not shown in the figure) connected by the connecting rod 406 will crush the mud cake on the cutting device 404, so that the mud cake is divided into specific sizes by the cutting device 404 (the cutting device 404 is in a square grid shape in the horizontal direction) and falls downward into the storage bin 408; a conveying pipe 409 is fixed to the lower end of the storage bin 408, and a third motor 410 is fixed to one end of the conveying pipe 409. In an optional subsequent process, the third motor 410 is started to drive the spiral blades in the spiral conveying pipe 409 to rotate, so that the divided mud cake inside the conveying pipe 409 can be conveyed, which is convenient for subsequent transportation operations.

[0050] In the first filter press 4 of this embodiment, a filter cloth with a larger pore size than that of the filter press in the related art is preferably used. In the technical solution of the embodiment, the filter cloth material is a polypropylene woven filter cloth, the pore size of the filter cloth at the liquid inlet is selected to be 0.80mm to 0.85mm, and the pore size of the filter cloth at the filtrate outlet side is controlled to be 0.50mm to 0.55mm.

[0051] Usually, in the selection of filter cloth for filter press, the pore size is usually less than 0.3mm, and more preferably less than 0.2mm, which is usually for more effective removal of solid residues or waste. However, in the implementation process of the present invention, in order to effectively obtain high value-added metal fine particles (such as Ni, Cr in high-grade metal electrophoretic paint) or dust retained in the electrophoretic paint, a larger size filter cloth is preferred to filter the finer metal particles (and possibly other oxides or solid particle impurities) and retain them in the filtrate.

[0052] The liquid filtered by the filter press assembly 401 is collected by the liquid collection tank 411. In a preferred embodiment of the utility model, a spiral stirring paddle is arranged in the liquid collection tank 411 to continuously stir the liquid to prevent the precipitation of fine metal particles in the filtrate, so as to facilitate the screening of metal particles in the subsequent steps and improve the sorting efficiency. The liquid collection tank 411 can be pumped to the next step for further processing.

[0053] Furthermore, this embodiment describes the wastewater fine particle separation device 5 used in the apparatus.

[0054] refer to Figure 3 , Figure 3 A schematic cross-sectional view of a wastewater fine particle separation device 5 is shown. The processing waste removal unit 5 has wastewater FW containing fine particle impurities delivered from the pipeline of the first filter press 4 of the previous stage via a pump 501. The wastewater fine particle separation device 5 is provided with a fine particle collection device 502, which introduces the wastewater FW. The fine particle collection device 502 includes a water storage tank 503 for storing the wastewater FW, a metal particle separation mechanism 504 partially immersed in the water storage tank 503, and a metal particle recovery mechanism 505.

[0055] During the operation of the fine particle collection device 502, the metal particle separation mechanism 504 will separate the solids carrying the metal fine particles M and other solid / liquid wastes, so that the metal fine particles M are separated from the wastewater FW stored in the water tank 503. The metal particle separation mechanism 504 includes a plurality of cathode electrode plates 506 disposed in the water storage tank 503, and a plurality of immersion rollers 507 disposed between the cathode electrode plates 506. A plurality of suspended rollers 508 are disposed above each cathode plate 506. In addition to the plurality of suspended rollers 508, the device also has a plurality of suspended rollers 508 disposed above the suspended rollers 508. Figure 3 The right electric motor 509 , the driving roller 510 driven by the electric motor 509 , and the driven roller 511 .

[0056] During the process, the endless steel belt 512 is wound around the driven roller 511 and the Figure 3On each of the above rollers shown. One end of the DC power supply 516 in the figure applies a negative (-) voltage to the cathode electrode plate 506, and applies a positive (+) voltage to the endless steel belt 512. The endless steel belt 512 is made by cutting a thin stainless steel plate. The immersion roller 507 wound with the endless steel belt 512 is immersed in the wastewater FW stored in the water tank 503. At this time, the fine metal particles M are mixed with other solid impurities and liquid phases, and may be located in the lower and middle parts of the water tank 503. A discharge port 513 (with a control switch) is also provided in a direction perpendicular to the cross-sectional view to discharge the wastewater after the fine metal particles M have been removed for use in the next stage of treatment at an appropriate time.

[0057] In the device, a metal particle recovery mechanism 505 is provided, which has a recovery box 514. During the operation of the device, a DC power supply 516 energizes the cathode electrode plate 506 and the endless steel belt 512, and operates the electric motor 509 to move the endless belt 512 as shown by the arrow. As the steel belt rotates in the direction shown, the metal fine particles M, which are negatively charged due to the opposite voltage applied by the electrodes, are repelled by the negatively charged cathode plate 506; at the same time, as the endless steel belt 512 is positively charged, the metal fine particles M are quickly adsorbed and brought out of the liquid surface by the rotation of the steel belt to complete the separation.

[0058] Here, the metal fine particles M absorbed on the endless steel belt 512 are transported by the endless belt, stripped at the stripping portion 515 on the recovery box 514, fall into the recovery box 514 and are recovered. In this way, the metal fine particles M are effectively extracted and collected from the wastewater FW stored in the water tank 503. The stripping portion 515 is selected as a non-metallic resin sheet or plastic sheet, and the stripping portion 515 is close to the surface of the endless steel belt 512 and fixed. It is worth noting that among the fine particles in the electrophoresis wastewater, there are not only metal fine particles, but also undesirable impurity particles in other electrochemical reactions, such as organic particles or oxide particles oxidized by the electrochemical process. However, the charging efficiency of organic particles and oxide particles under the action of electrode orientation is much lower than that of metal particles, so most of these particles will not be extracted, and the residual metal fine particles in the liquid are significantly and effectively separated and extracted.

[0059] In the process implemented by the present invention, the DC power supply 516 is only set to repel and adsorb metal particles, and it is not expected to induce unnecessary electrochemical reactions. Therefore, in the process implemented by the present application, the voltage of the DC power supply is controlled at 30V to 90V, and should not exceed 100V. In the industrial application process, according to the experiments of the utility model, the voltage of the DC power supply 516 that is most effective in separating metal fine particles and other impurities is preferably set to 48V or 64V.

[0060] In the setting and operation of the equipment, the immersion roller 507 is preferably immersed at about one-half of the entire depth of the water tank 503. If the immersion depth is too shallow, the area of ​​the electrode-driven metal particles to move and adsorb is reduced. If the immersion depth is too deep, the resistance of the steel belt during movement increases, which is not conducive to the efficient operation of the equipment. In addition, a spiral stirring device is provided at the cathode electrode plate 506 at the bottom of the water tank 503 and / or the outside of the cathode electrode plate 506. The spiral stirring device runs at a relatively low speed (60r / min to 100r / min), which is conducive to stirring and mixing the metal particles precipitated at the bottom in the middle of the wastewater, and does not interfere with or hinder the directional adsorption of the metal particles toward the steel belt.

[0061] The wastewater discharged from the discharge port 513 is further processed and discharged through the oxidation alkalization flocculation tank 6, the second sedimentation tank 7, the second filter press 8, and the wastewater discharge device 9, so as to complete the entire electrophoresis wastewater treatment process.

[0062] According to the combination of the wastewater fine particle separation device and the specific filter press device of Example 1, metal particles in the electrophoretic wastewater with high added value are effectively extracted and utilized. In the wastewater treatment process collected in the typical motor vehicle metal paint electrophoretic coating process, 150 grams of metal Cr and Ni fine particles per ton of waste liquid can be obtained in the wastewater fine particle separation device. These particles can effectively increase the added value of the by-products of the electrophoretic wastewater in the batch wastewater treatment process, and facilitate the continuous operation and production of the entire extraction process.

[0063] Example 2

[0064] This example describes the wastewater treatment process performed by the apparatus of Example 1.

[0065] Step 1) Demulsification step: In the demulsification tank, inorganic salts are added to the electrophoretic paint wastewater to be treated for demulsification, 20 g / L of magnesium sulfate is added to the demulsification tank according to the mass of the wastewater, the wastewater mixed liquid system is stirred for 3-5 minutes, and then 10 wt% of dilute sulfuric acid is gradually added to adjust the pH value, and the pH value is detected by the pH value monitor in the demulsification tank until the pH value is adjusted to 1-3, and then the addition of sulfuric acid is stopped;

[0066] Step 2) flocculation precipitation: add flocculant polyacrylamide (addition amount 10g / L) to the demulsification system in step 1), and let it stand for 15 minutes, so that the solid impurities in the system form colloidal polymerization nuclei, and the colloidal molecules collide and combine with each other to form huge colloidal molecules, thereby forming a flocculated precipitate;

[0067] Step 3) First filter pressing step: The precipitate and liquid phase obtained in step 2) are transported to a first filter press device. The specific device and structure of the first filter press will be described in Example 2. In the selection of filter cloth for the first filter press, the filter cloth material is a polypropylene woven filter cloth. The pore size of the filter cloth at the liquid inlet is selected to be 0.80 mm to 0.85 mm, and the pore size of the filter cloth at the filtrate outlet side is controlled to be 0.50 mm to 0.55 mm. The solid part obtained after the filter pressing is further treated as solid waste (first sludge), and the pressed filtrate enters the next step for further treatment;

[0068] Step 4) separation of fine particles from wastewater: the filtrate (containing fine metal particles) in step 3) is passed through a conveying pipeline into a wastewater fine particle separation device to separate fine metal particles. In this step, fine metal particles with a particle size of less than 0.5 mm are directly separated from the filtrate in step 3). The specific process of this step and the wastewater fine particle separation device have been described in more detail in Example 1. The waste liquid treated by the annular belt suction device, the electrode device and the solid recovery device of the wastewater fine particle separation device is further transported to the next step;

[0069] Step 5) Oxidation flocculation step: the waste liquid separated from the fine particles in step 4) enters an oxidation alkalization flocculation device, into which ozone (H2O2, concentration of 0.05 mg / L) is introduced for oxidation, and after oxidation, a sodium hydroxide solution with a mass concentration of 2%wt is added to adjust the pH value to 9 to 11; then 0.5 to 1.5 mg / L of ferrous sulfate solution is added for disinfection and impurity removal; then polyaluminium chloride flocculant (PAC) is added to the system, and the addition amount is controlled at 150-170 ppm, and then it enters a sedimentation tank for precipitation;

[0070] Step 6) Second filter pressing step: filter the mixed solution delivered from step 5) by filter pressing, the filter pressing equipment adopts the same filter press device as step 3), except that the pore size of the filter cloth on the side where the filtrate enters is selected to be 0.15 to 0.2 mm, and the pore size of the filter cloth on the side where the filtrate flows out is selected to be 0.06-0.08 mm;

[0071] After step 6), the obtained sludge (second sludge) enters the subsequent treatment process, and the filtered water reaches the discharge and secondary utilization standards, and can be subjected to the corresponding post-treatment and recycling steps.

[0072] According to the process steps of Example 2, 150 grams of metal Cr and Ni fine particles per ton of waste liquid can be obtained in the wastewater fine particle separation device in step 4), and the particles can be directly screened and transported to the non-ferrous metal or other alloy chemical fields for subsequent fine processing without being subjected to strong oxidation treatment with the first sludge to form salt and then subjected to deep processing. The recycling and utilization of fine metal particles in this process significantly improves the recycling value of by-products in the electrophoretic paint wastewater recycling process, and avoids the environmental pressure and post-processing cost when strong acids and alkalis are used in large quantities to dissolve harmful metals in subsequent treatment processes.

[0073] Example 3

[0074] In Example 3, most of the processes of Example 2 are performed using the equipment of Example 1. Different from Example 2, in step 5) the oxidation flocculation step, alkali and flocculant are used separately in multiple steps.

[0075] Specifically, in this embodiment, step 5) is an oxidation flocculation step: the waste liquid separated from fine particles in step 4) enters an oxidation alkalization flocculation device, and ozone (H2O2, concentration is 0.05mg / L) is introduced therein for oxidation. After oxidation, 2%wt of sodium hydroxide solution is first added to adjust the pH value to 7.5-8.5, and then 0.5 to 1.5mg / L of ferrous sulfate solution is added for disinfection and impurity removal; then 30ppm of the first polyaluminum chloride flocculant (PAC) is added to the system and fully stirred; then, 1%wt of sodium hydroxide solution is added to adjust the pH value to 9-10, and 40ppm of the second polyaluminum chloride flocculant (PAC) is added for full stirring; again, 1%wt of sodium hydroxide solution is added to adjust the pH value to 10.5-11.5, and 20ppm of the third polyaluminum chloride flocculant (PAC) is added for full stirring. Subsequently, the waste liquid enters a sedimentation tank for sedimentation operation (step 6) and step 7) of embodiment 1.

[0076] According to step 5) of Example 3, by precisely controlling the wastewater pH value and the amount of PAC added, a better COD purification effect can be achieved (the COD content of the effluent from the sedimentation tank of Example 1 is 650 mg / L, while the COD content of the effluent from the sedimentation tank of Example 3 is 590 mg / L), while reducing the use of the expensive flocculant polyaluminum chloride flocculant (PAC), which can save about 15% of the flocculant polyaluminum chloride flocculant.

[0077] According to the implementation scheme and technical content recorded in the specification of the utility model, the utility model can at least provide the following technical solutions: Although the present disclosure includes specific embodiments, it is obvious to those skilled in the art that various formal and detailed replacements or changes can be made to these embodiments without departing from the main points and scope of the utility model of the present claims and their equivalent technical solutions. The embodiments described herein should be considered to be illustrative only and not for the purpose of limitation. The description of the features and aspects in each embodiment is considered to be applicable to similar features and aspects in other embodiments. Therefore, the scope of the present disclosure should not be limited by the specific description, but by the technical solutions of the claims, and all changes within the scope of the claims and their equivalents are interpreted as being included in the technical solutions of the present disclosure.

Claims

1. An electrophoretic paint wastewater treatment device, characterized in that: The electrophoretic paint wastewater treatment device comprises an electrophoretic paint wastewater storage tank, a demulsification tank, a first sedimentation tank, a first filter press, a wastewater fine particle separation device, an oxidation alkalization flocculation tank, a second sedimentation tank, a second filter press, and a wastewater discharge device connected in sequence, and the electrophoretic paint wastewater treatment device also comprises a first sludge receiving tank connected to the first filter press and a second sludge receiving tank connected to the second filter press; as well as The first filter press comprises a filter press assembly, wherein the pore size of the filter cloth in the filter press assembly is between 0.50 mm and 0.90 mm; the second filter press comprises a filter press assembly, wherein the pore size of the filter cloth in the filter press assembly of the second filter press is between 0.05 mm and 0.30 mm, and The pore size of the filter cloth of the first filter press at the water inlet is 0.80 mm to 0.85 mm, and the pore size of the filter cloth at the filtrate outlet side is controlled to be 0.50 mm to 0.55 mm; and The pore size of the filter cloth of the second filter press on the side where the filtrate enters is 0.15mm to 0.20mm, and the pore size of the filter cloth on the side where the filtrate flows out is 0.06mm to 0.08mm.

2. An electrophoretic paint wastewater treatment device according to claim 1, characterized in that: The wastewater fine particle separation device comprises: A pump for conveying wastewater containing fine particulate impurities transmitted from a pipeline of a first filter press at an upper stage; A fine particle collection device, comprising a water storage tank for storing wastewater, a metal particle separation mechanism partially immersed in the water storage tank, and a metal particle recovery mechanism; and The metal particle separation mechanism comprises a plurality of cathode electrode plates disposed in the water storage tank, a plurality of submerged rollers disposed between the cathode electrode plates, and a plurality of suspended rollers disposed above the plurality of cathode electrode plates; wherein the plurality of submerged rollers are submerged in the filtrate of the water storage tank; The device also includes an electric motor disposed above the suspended roller, a driving roller driven by the electric motor, and a driven roller; an endless steel belt, the endless steel belt being wound around the driving roller, the driven roller, the plurality of submerged rollers, and the plurality of suspended rollers; A direct current power supply, one end of which applies a negative voltage to the cathode electrode plate and a positive voltage to the endless steel belt; A metal particle recovery mechanism comprises a recovery box and a stripping portion above the recovery box, wherein the stripping portion is closely attached to the surface of the endless steel belt and is fixed.

3. The electrophoretic paint wastewater treatment device according to claim 2, characterized in that: The recovery box is arranged below the portion of the endless steel belt that is not immersed in the water storage tank.

4. The electrophoretic paint wastewater treatment device according to claim 2, characterized in that: The plurality of cathode electrode plates are disposed on both sides of each immersion roller.

Images