Electroplating wastewater multi-stage treatment device and treatment method

Abstract

The invention relates to the technical field of electroplating wastewater treatment, in particular to an electroplating wastewater multi-stage treatment device and method. The oil separation mechanism is used for standing the waste liquid to remove impurities; the air flotation mechanism is used for demulsifying and removing impurities from the waste liquid; the driving mechanism is used for driving the impurity removal assembly; the oil separation mechanism and the air flotation mechanism are symmetrically arranged on the two sides of the oil separation mechanism, and the driving mechanism is arranged on the supporting plate. The arranged electrode plates rotating along with the rotating column are communicated through the contact elastic pieces, and the polarities of the electrode plates are periodically switched in the rotating process, so that floccules and microbubbles can be periodically generated on the surfaces of the electrode plates with different polarities, the contact probability of the bubbles and the floccules is greatly increased, and the flocculation effect is improved. Meanwhile, microbubbles generated by continuous flowing are relatively small in diameter and are in contact with a flocculating constituent in the wastewater, so that the treatment effect on the grease is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroplating wastewater treatment, and in particular to a multi-stage electroplating wastewater treatment device and a treatment method. Background Art

[0002] The electroplating industry is a key component of mechanical manufacturing and surface treatment. However, the wastewater generated during its production process is complex, containing high concentrations of heavy metal ions, organic additives, emulsified oils, and other pollutants. This wastewater is highly toxic and poorly biodegradable. If discharged without effective treatment, it will severely damage the aquatic ecosystem and endanger human health.

[0003] Existing electroplating wastewater treatment processes mostly utilize a multi-stage process combining physical and chemical pretreatment with biochemical advanced treatment. The pretreatment stage typically involves coagulation-flocculation-flotation, aiming to separate suspended solids and grease by adding demulsifiers and flocculants. However, existing technologies have some shortcomings. Electroplating wastewater contains a large amount of emulsified grease with fine particle size and high stability. Traditional flotation processes, which mostly use conventional perforated tube aeration, employ a crude aeration method, resulting in large and unevenly distributed bubbles that are difficult to fully collide with and adhere to oil droplets. This results in incomplete oil-water separation and a high residual grease content.

[0004] High levels of residual grease can easily trap heavy metal ions and organic pollutants, hindering flocculation and sedimentation efficiency. Furthermore, grease coats the surface of biofillers, inhibiting microbial activity and reducing biochemical treatment efficiency. This, in turn, impacts electroplating wastewater treatment effectiveness. To address this issue, we propose a multi-stage electroplating wastewater treatment device and method. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-stage treatment device and treatment method for electroplating wastewater, which solves the problem in the prior art that the contact efficiency between aeration bubbles and oil droplets is low, affecting the grease treatment efficiency in wastewater.

[0006] To achieve the above object, the present invention provides the following technical solutions: A multi-stage electroplating wastewater treatment device and method includes a support plate; Oil separator, used to keep waste liquid stationary and remove impurities; Air flotation mechanism, used to demulsify and remove impurities from waste liquid; A driving mechanism, used for driving the impurity removal component; The oil separation mechanism and the air flotation mechanism are symmetrically arranged on both sides of the oil separation mechanism, and the driving mechanism is arranged on the support plate.

[0007] Preferably, the oil separator mechanism includes an oil separator, the oil separator is fixedly connected to the side of the support plate, a limit plate is fixedly connected to the oil separator, and a collection tank is fixedly connected to the end of the limit plate.

[0008] Preferably, the flotation mechanism comprises a flotation tank, which is fixedly connected to the side of the support plate away from the grease trap, a downwardly inclined deflection plate is fixedly connected inside the flotation tank, and a flocculation component is provided inside the flotation tank.

[0009] Preferably, a collection box is connected above the grease trap and the flotation tank, the collection box is fixedly connected to the support plate, a scraper is fixedly connected to the top of the collection box, and a connecting waterway is fixedly connected between the grease trap and the flotation tank.

[0010] Preferably, the limiting plate includes a top plate and a bottom plate, the top plate is fixedly connected to the top of the pretreatment tank, and one end of the top plate is tilted downward, the top plate is fixedly connected to one side of the short side of the collection tank, the bottom plate is fixedly connected to the bottom of the pretreatment tank, and one end of the bottom plate is tilted upward, and the bottom plate is fixedly connected to one side of the long side.

[0011] Preferably, the driving mechanism includes a rotating column, which is rotatably connected in the middle of a support plate, a motor is provided on the support plate, a synchronous wheel is fixedly connected to the rotating column and the end of the motor output shaft, a synchronous belt is provided on the outer side of the synchronous wheel, a synchronous wheel 2 is fixedly connected to the rotating column, and a synchronous belt 2 is provided on the outer side of the synchronous wheel 2.

[0012] Preferably, the oil separator mechanism also includes a skimming assembly, which includes a support frame fixedly connected to the second side of the synchronous belt, the bottom end of the support frame is rotatably connected to a skimming plate, and one end of the skimming plate is fixedly connected to a spring.

[0013] Preferably, the flocculation component includes a bracket, which is fixedly connected to the outside of the second synchronous belt, and a slag cleaning plate is rotatably connected to the bracket, and a second spring is fixedly connected to the slag cleaning plate, and an electrode plate is fixedly connected to the bottom end of the slag cleaning plate.

[0014] Preferably, a contact spring is connected to the side of the flotation tank, and the contact spring includes an elastic contact piece fixedly connected to the slag cleaning plate and a terminal slide rail fixedly connected to the side of the flotation tank.

[0015] Preferably, the method comprises the following steps: S1. Pretreatment of wastewater; S1.1. Static treatment of wastewater: The electroplating wastewater is passed into the grease trap and slowly moved in the grease trap to achieve static treatment, so that the light oil layer floats up and the sediment sinks to achieve preliminary impurity removal; S1.2, Demulsification treatment of wastewater: After standing, the wastewater flows into the flotation tank, where the complex generated by the electrode plate and the oil droplets undergo electrostatic neutralization to form flocs. The microbubbles generated by the electrode plate can make the flocs float, achieving secondary demulsification and impurity removal. S2. Primary treatment of wastewater: The pre-treated wastewater flows to the primary treatment equipment, where it reacts with heavy metal ions in the wastewater through multiple series-connected reaction tanks to generate precipitates, and the precipitates are separated to remove heavy metal ions in the wastewater; S3. Secondary treatment of wastewater: The wastewater that has completed primary treatment flows to the secondary treatment equipment, where it is biologically treated by a biochemical treatment device or oxidized by an oxidation treatment device; S4, sludge treatment; the sludge collected in steps S1, S2, and S3 is concentrated, and the concentrated sludge is dehydrated to form a mud cake to facilitate subsequent sludge treatment.

[0016] By means of the above technical solution, the present invention provides a multi-stage electroplating wastewater treatment device and treatment method having at least the following beneficial effects: (1) The present invention connects the electrode plates that rotate with the rotating column through contact springs, and periodically switches the polarity of the electrode plates during the rotation process, so that flocs and microbubbles are periodically generated on the surfaces of the electrode plates with different polarities, greatly increasing the probability of contact between bubbles and flocs. At the same time, the microbubbles generated by continuous flow have a smaller diameter and contact with the flocs inside the wastewater, thereby improving the treatment effect on grease.

[0017] (2) The present invention can dissolve the passivation layer produced by anode corrosion by using the cathode phase reduction reaction by setting the electrode plate with continuously switching polarity, thereby maintaining the activity of the electrode plate as an anode, extending the life of the electrode plate, reducing the frequency of electrode plate replacement, and improving the treatment effect of wastewater.

[0018] (3) The skimming plate and the slag cleaning plate provided in the present invention can slide on the surface of the wastewater, collect and clean the grease or flocculent impurities floating on the surface of the wastewater, and improve the grease cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application: Figure 1 The structure of the present invention is schematically shown Figure 1 ; Figure 2 The structure of the present invention is schematically shown Figure 2 ; Figure 3 It is a schematic structural diagram of the oil separation mechanism of the present invention; Figure 4 Schematic diagram of the internal structure of the oil separator mechanism of the present invention; Figure 5 For the present invention Figure 4 A magnified schematic diagram of point A; Figure 6 Schematic diagram of the oil separation mechanism of the present invention Figure 1 ; Figure 7 Schematic diagram of the oil separation mechanism of the present invention Figure 2 ; Figure 8 Schematic diagram of the internal structure of the oil separator mechanism of the present invention; Figure 9 It is a schematic structural diagram of the slag cleaning plate of the present invention.

[0020] In the figure: 1. Support plate; 2. Oil separator; 21. Oil separator; 22. Limit plate; 221. Top plate; 222. Bottom plate; 23. Collecting trough; 24. Skimmer assembly; 241. Support frame; 242. Skimmer plate; 243. Spring 1; 3. Flotation mechanism; 31. Flotation tank; 32. Steering plate; 33. Flocculation assembly; 331. Bracket; 332. Cleaning plate; 334. Electrode plate; 34. Contact spring; 341. Elastic contact piece; 342. Terminal slide rail; 4. Collecting box; 5. Scraper; 6. Connecting waterway; 7. Driving mechanism; 71. Rotating column; 72. Motor; 73. Synchronous wheel 1; 74. Synchronous belt 1; 75. Synchronous wheel 2; 76. Synchronous belt 2. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Example 1 A multi-stage electroplating wastewater treatment device, such as Figure 1-Figure 5 As shown, it includes a support plate 1; an oil separation mechanism 2 is provided on the side of the support plate 1 for statically removing impurities from the waste liquid; a driving mechanism 7 is provided on the support plate 1 for driving the impurity removal component.

[0023] Specifically, the oil separator 2 includes a grease trap 21, fixedly attached to the side of the support plate 1. A limit plate 22 is fixedly attached to the grease trap 21, and a collection trough 23 is fixedly connected to the end of the limit plate 22. The grease trap 21 allows the electroplating waste liquid to rest, allowing the oil in the waste liquid to float up and the sediment to sink and separate. The grease trap 21 has a small height difference at both ends, allowing the wastewater to flow slowly from one end to the other. The collection trough 23 includes a short side close to the grease trap 21 and a long side away from the grease trap 21.

[0024] Furthermore, the limiting plate 22 includes a top plate 221 and a bottom plate 222. The top plate 221 is fixedly connected to the top of the pretreatment tank, and one end of the top plate 221 is tilted downward. The top plate 221 is fixedly connected to one side of the short side of the collection tank 23. The downward tilted top plate 221 can guide the grease floating on the top when the wastewater flows, which is convenient for the collection operation of the grease. At the same time, the collection tank 23 is a U-shaped structure, and the top plate 221 can guide the grease to be collected inside the collection tank 23.

[0025] On this basis, the bottom plate 222 is fixedly connected to the bottom of the pretreatment tank, and one end of the bottom plate 222 is tilted upward. The bottom plate 222 is fixedly connected to one side of the long side of the collection tank 23. The upward tilted bottom plate 222 can guide and collect the sediment on the bottom layer. The top plate 221 and the bottom plate 222 cooperate with each other to form an eight-shaped structure, which facilitates the flow of wastewater to the subsequent treatment structure after guiding the impurities on the top and bottom layers into the collection tank 23.

[0026] It is worth noting that the drive mechanism 7 includes a rotating column 71, which is rotatably connected to the middle of the support plate 1. The support plate 1 is provided with a motor 72. The end of the rotating column 71 and the end of the output shaft of the motor 72 are fixedly connected to a synchronous wheel 73. The outer side of the synchronous wheel 73 is provided with a synchronous belt 74. The rotating column 71 is structurally rotatably connected to the support plate 1 and can be driven by the motor 72. The synchronous wheel 73 and the synchronous belt 74 can transmit the rotation output by the motor 72 to the rotating column 71. The rotating column 71 is fixedly connected to the synchronous wheel 75, and the outer side of the synchronous wheel 75 is provided with a synchronous belt 76.

[0027] The grease trap 21 is then moved back to the top of the grease trap 21 and the grease is then moved back to the top of the grease trap 21. The grease is then moved back to the top of the grease trap 21 and the grease is then moved back to the top of the grease trap 21.

[0028] In addition, a collection box 4 is connected above the grease trap 21, and the collection box 4 is fixedly connected to the support plate 1. A scraper 5 is fixedly connected to the top of the collection box 4. The collection box 4 structure can collect grease impurities on the skimming plate 242, and the scraper 5 structure can clean the surface of the skimming plate 242.

[0029] Example 2 like Figure 1 、 Figure 2 、 Figure 6-Figure 9 As shown, on the basis of Example 1, an air flotation mechanism 3 is provided on the side of the support plate 1 for demulsifying and removing impurities from the waste liquid.

[0030] In this embodiment, the flotation mechanism 3 includes a flotation tank 31, which is fixedly connected to the side of the support plate 1 away from the oil-water separator 21. A downward-inclined deflector plate 32 is fixedly connected to the inside of the flotation tank 31. A flocculation component 33 is provided inside the flotation tank 31. The flotation tank 31 can re-treat the wastewater after oil-water treatment. The deflector plate 32 structure has a function similar to that of the top plate 221, and can guide the floating impurities for collection and treatment.

[0031] On this basis, a collection box 4 is connected above the flotation tank 31, and a connecting waterway 6 is fixedly connected between the grease trap 21 and the flotation tank 31. The connecting waterway 6 can connect the grease trap 21 and the flotation tank 31 to each other, so that the waste liquid treated in the grease trap 21 flows into the flotation tank 31.

[0032] Furthermore, the flocculation assembly 33 includes a bracket 331, which is fixedly connected to the outside of the second synchronous belt 76. A slag removal plate 332 is rotatably connected to the bracket 331, and an electrode plate 334 is fixedly connected to the bottom end of the slag removal plate 332. The bracket 331 structure supports the flocculation assembly 33, allowing the flocculation assembly 33 to continuously rotate with the second synchronous belt 76. At the same time, the electrode plate 334 structure can treat the slowly flowing wastewater in the flotation tank 31. The electrode plate 334 is made of stainless steel, and the end of the electrode plate 334 is made of an insulating material. The electrode plate 334 has a mesh or grid structure to facilitate the passage of wastewater through the electrode plate 334.

[0033] On this basis, a contact spring 34 is connected to the side of the flotation tank 31. The contact spring 34 includes an elastic contact member 341 fixedly connected to the slag cleaning plate 332 and a terminal rail 342 fixedly connected to the side of the flotation tank 31. The contact spring 34 ensures that the electrode plate 334 remains energized during rotation with the bracket 331. The contact spring 34 also enables the electrode plate 334 to switch its polarity during rotation. The terminal rail 342 is located in the middle area of ​​the side of the flotation tank 31 to prevent short circuits caused by contact between the electrode plates 334 at both ends of the flotation tank 31 as the slag cleaning plate 332 rotates.

[0034] When the multi-stage electroplating wastewater treatment device of the present invention is used, the electroplating wastewater is first fed into the grease trap 21. The wastewater then flows slowly along the spiral grease trap 21, and the grease and sediment in the wastewater are gradually separated from the wastewater during the slow flow. Simultaneously, the rotating column 71 and the synchronous belt 2 76 rotate continuously under the drive of the motor 72, and the skimmer plate 242 is driven to rotate continuously via the support frame 241. The rotation direction of the synchronous belt 2 76 is the same as the flow direction of the wastewater, and the rotation speed of the synchronous belt 2 76 is faster than the flow speed of the wastewater and slower than 1.5 times the flow speed of the wastewater. Therefore, the relative speed between the synchronous belt 2 76 and the wastewater is low. In addition, the inclination direction of the skimmer plate 242 is the rotation direction of the synchronous belt 2 76. The skimmer plate 242, which moves slowly along the wastewater, can skim grease from the surface of the wastewater to the inclined surface of the skimmer plate 242. When the skimmer plate 242 rotates with the support frame 241 to the top plate 221, the end of the top plate 221 restrains the skimmer plate 242, causing it to rotate from tilting in the same direction as the rotation to tilting in the opposite direction. As the skimmer plate 242 rotates, grease on its surface slides between the skimmer plate 242 and the top plate 221. After rotating, the skimmer plate 242, sliding along the top plate 221 in its reversed direction, scrapes the grease between the two sides into the collection tank 23. The skimmer plate 242 then rotates above the collection tank 4, where the scraper 5 completely scrapes any remaining grease from the skimmer plate 242 into the collection tank 4. Because the wastewater flows slowly, impurities that settle to the bottom of the wastewater do not flow with the wastewater. Even if impurities do flow with the wastewater, the upward-tilted bottom plate 222 guides them into the collection tank 23. After the skimmer plate 242 moves away from the scraper 5 or the top plate 221, the spring 1 243 rotates and resets the skimmer plate 242 due to its own elasticity. Wastewater treated in the grease trap 21 flows along the connecting waterway 6 into the flotation tank 31. The slag cleaning plate 332 and electrode plate 334 on the bracket 331 rotate continuously along the synchronous belt 2 76. Simultaneously, the elastic contact member 341 on the bracket 331 contacts the terminal slide 342 fixedly connected to the side of the flotation tank 31, connecting the electrode plates 334. Adjacent electrode plates 334 have opposite polarities, causing the electrode plates 334 to alternately form cathodes and anodes. The iron in the anode electrode plate 334 dissolves to form ferrous ions, which are oxidized by dissolved oxygen in the wastewater to form ferric ions. The ferrous ions hydrolyze to form a colloid of a polynuclear hydroxyl complex. The positively charged colloid then neutralizes the negative charge of the oil droplets or heavy metals. Simultaneously, the colloidal network captures suspended particles to form floc nuclei. Ultrafine hydrogen bubbles are generated near the cathode electrode plate 334, preferentially adhering to oil droplets and hydrophobic flocs. As the bracket 331 rotates continuously with the synchronous belt 2 76, the elastic contact member 341 on the bracket 331 slides and switches between different terminal rails 342, continuously switching the polarity of the electrode plate 334 within a set time. During the switching and stirring of the electrode plate 334, hydrogen bubbles are generated directly near the flocs, significantly increasing the probability of collision between the flocs and the bubbles, thereby increasing the probability of the flocs floating.The continuously switching electrode plates 334 exhibit a self-cleaning and anti-passivation effect, dissolving the passivation layer at set intervals, thereby maintaining the activity of the anode electrode plates 334. The cleaning plates 332 scrape floccules that rise to the wastewater surface toward the deflector plates 32. Within the constraints of the deflector plates 32, the cleaning plates 332 rotate and switch their tilt. When the electrode plates 334 move toward the end of the deflector plates 32 or the end of the scraper plates 5, the deflector plates 32 or scraper plates 5 remove impurities adhering to the surface of the electrode plates 334, preventing them from affecting their function. The wastewater, having completed the flotation treatment, is discharged for subsequent treatment.

[0035] Example 3 A multi-stage treatment method for electroplating wastewater, such as Figures 1-9 As shown, the following steps are included: First, the wastewater is pretreated. The electroplating wastewater is passed into the grease trap 21, where it is allowed to settle slowly, causing the light oil layer to float up and the sediment to sink, achieving preliminary impurity removal. After settling, the wastewater flows into the flotation tank 31, where the complex generated by the electrode plate 334 electrostatically neutralizes the oil droplets, forming flocs. The microbubbles generated by the electrode plate 334 can cause the flocs to float, achieving secondary demulsification and impurity removal. The wastewater is then subjected to primary treatment. The pre-treated wastewater flows into the primary treatment equipment, where it reacts with the heavy metal ions in the wastewater through multiple series-connected reaction tanks to generate precipitates, which are then separated to remove the heavy metal ions in the wastewater. Then the wastewater undergoes secondary treatment; the wastewater that has completed primary treatment flows to the secondary treatment equipment, where it undergoes biological treatment through a biochemical treatment device or oxidation treatment through an oxidation treatment device. The sludge generated and collected during the pretreatment, primary treatment and secondary treatment of wastewater is concentrated, and the concentrated sludge is dehydrated to form mud cake to facilitate subsequent sludge treatment.

[0036] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0037] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multi-stage electroplating wastewater treatment device, characterized by: comprising a support plate (1); An oil separator (2) is used to allow the waste liquid to stand and remove impurities; An air flotation mechanism (3) is used to demulsify and remove impurities from the waste liquid; A driving mechanism (7) for driving the impurity removal component; The oil separation mechanism (2) and the air flotation mechanism (3) are symmetrically arranged on both sides of the oil separation mechanism (2), and the driving mechanism (7) is arranged on the support plate (1).

2. The multi-stage electroplating wastewater treatment device according to claim 1, characterized in that: The oil separator mechanism (2) comprises an oil separator (21), the oil separator (21) being fixedly connected to the side of the support plate (1), a limiting plate (22) being fixedly connected to the oil separator (21), and a collecting tank (23) being fixedly connected to the end of the limiting plate (22).

3. The multi-stage electroplating wastewater treatment device according to claim 1, characterized in that: The flotation mechanism (3) comprises an air flotation tank (31), the air flotation tank (31) being fixedly connected to a side of the support plate (1) away from the oil separator (21), a deflection plate (32) tilted downward being fixedly connected inside the air flotation tank (31), and a flocculation assembly (33) being provided inside the air flotation tank (31).

4. The multi-stage electroplating wastewater treatment device according to claim 2, characterized in that: A collection box (4) is connected above the grease trap (21) and the flotation tank (31), the collection box (4) is fixedly connected to the support plate (1), a scraper (5) is fixedly connected to the top of the collection box (4), and a connecting waterway (6) is fixedly connected between the grease trap (21) and the flotation tank (31).

5. The multi-stage electroplating wastewater treatment device according to claim 2, characterized in that: The limiting plate (22) comprises a top plate (221) and a bottom plate (222), wherein the top plate (221) is fixedly connected to the top of the pretreatment tank, and one end of the top plate (221) is tilted downward, and the top plate (221) is fixedly connected to one side of the short side of the collecting tank (23), and the bottom plate (222) is fixedly connected to the bottom of the pretreatment tank, and one end of the bottom plate (222) is tilted upward, and the bottom plate (222) is fixedly connected to one side of the long side of the collecting tank (23).

6. The multi-stage electroplating wastewater treatment device according to claim 1, characterized in that: The driving mechanism (7) includes a rotating column (71), the rotating column (71) is rotatably connected to the middle of a support plate, a motor (72) is provided on the support plate, a synchronous wheel is fixedly connected to the rotating column (71) and the end of the output shaft of the motor (72), a synchronous belt is provided on the outer side of the synchronous wheel, a second synchronous wheel (75) is fixedly connected to the rotating column (71), and a second synchronous belt (76) is provided on the outer side of the second synchronous wheel (75).

7. The multi-stage electroplating wastewater treatment device according to claim 6, characterized in that: The oil separation mechanism (2) further includes a skimming assembly (24), the skimming assembly (24) including a support frame (241), the support frame (241) being fixedly connected to the side of the synchronous belt 2 (76), the bottom end of the support frame (241) being rotatably connected to a skimming plate (242), and one end of the skimming plate (242) being fixedly connected to a spring 1 (243).

8. The multi-stage electroplating wastewater treatment device according to claim 3, characterized in that: The flocculation assembly (33) includes a bracket (331), the bracket (331) is fixedly connected to the outside of the synchronous belt (76), a slag cleaning plate (332) is rotatably connected to the bracket (331), a spring (333) is fixedly connected to the slag cleaning plate (332), and an electrode plate (334) is fixedly connected to the bottom end of the slag cleaning plate (332).

9. The multi-stage electroplating wastewater treatment device according to claim 3, characterized in that: A contact spring (34) is connected to the side of the flotation tank (31), and the contact spring (34) comprises an elastic contact piece (341) fixedly connected to the slag cleaning plate (332) and a terminal slide rail (342) fixedly connected to the side of the flotation tank (31).

10. A multi-stage treatment method for electroplating wastewater, used in a multi-stage treatment device for electroplating wastewater according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Pretreatment of wastewater; S1.1, static treatment of wastewater; passing the electroplating wastewater into the grease trap (21), and slowly moving the wastewater in the grease trap (21) to achieve static treatment, so that the light oil layer floats up and the sediment sinks; S1.2, demulsification treatment of wastewater; after standing, the wastewater flows into the flotation tank (31), where the complex generated by the electrode plate (334) and the oil droplets undergo electrostatic neutralization to form flocs, which can be floated by the microbubbles generated by the electrode plate (334); S2. Primary treatment of wastewater: The pre-treated wastewater flows to the primary treatment equipment, where it reacts with heavy metal ions in the wastewater through multiple series-connected reaction tanks to generate precipitates, and the precipitates are separated to remove heavy metal ions in the wastewater; S3. Secondary treatment of wastewater: The wastewater that has completed primary treatment flows to the secondary treatment equipment, where it is biologically treated by a biochemical treatment device or oxidized by an oxidation treatment device; S4, sludge treatment; the sludge collected in steps S1, S2, and S3 is concentrated, and the concentrated sludge is dehydrated to form a mud cake.

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