A pretreatment device for treating anode oxidation nickel-containing wastewater by using chelation separation and complex precipitation technology

Abstract

The utility model relates to wastewater treatment technical field especially utilizes a kind of pretreatment device for treating anode oxidation nickel-containing wastewater using chelation separation and composite precipitation technology, including reaction zone, first sedimentation zone, second sedimentation zone and back call area, the reaction zone is used to carry out alkaline adjustment and precipitation treatment to wastewater, the first sedimentation zone is used to carry out primary sedimentation treatment to wastewater after alkaline adjustment and precipitation pretreatment, the second sedimentation zone is used to carry out secondary sedimentation treatment to wastewater after primary sedimentation treatment, the back call area is used to carry out acid-base neutralization treatment to wastewater after secondary sedimentation treatment.The utility model precipitates chelated nickel precipitate by reaction separation, and combined with the composite type sedimentation treatment of first sedimentation zone and second sedimentation zone, can remove nickel-containing pollutants comprehensively, efficiently and stably, ensure that effluent is continuously stable, to reach standard requirement.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology. Background Technology

[0002] With the increasing demand for high-performance aluminum materials from industries such as automobiles, consumer electronics, building materials, and aerospace, anodizing is a common metal surface treatment technology, mainly used for surface modification of aluminum and its alloys to improve corrosion resistance, wear resistance and decorative properties. However, this process also leads to an increase in the discharge of nickel-containing wastewater. In the anodizing industry, nickel-containing wastewater mainly originates from the use of nickel-containing sealants, commonly nickel acetate and nickel fluoride, to improve the corrosion resistance of aluminum oxide films. This leads to nickel ions entering the wastewater. Since nickel is a heavy metal pollutant, non-compliant discharge can cause various harms, including significant health risks. Long-term exposure to or ingestion of nickel-containing wastewater can lead to skin allergies (nickel dermatitis), respiratory diseases, liver and kidney damage, and even cancer. It also causes considerable toxicity to aquatic organisms, as nickel ions can damage cell membranes and enzyme systems, leading to the death of fish and algae and affecting the ecological balance of aquatic bodies. Furthermore, it causes significant soil pollution. Nickel-containing wastewater seeps into the soil, inhibits plant growth, and enters the food chain through bioaccumulation in crops, ultimately harming human health. Therefore, the state has very strict restrictions on the discharge of nickel-containing wastewater. The current traditional pretreatment method is to use alkaline adjustment and precipitation. By adjusting the pH to alkaline 10-11, Ni(OH)2 precipitate is generated. Then, it is separated and removed by PAC and PAM flocculation and sedimentation tank to remove nickel heavy metals. However, this pretreatment method often has significant drawbacks. Traditional sedimentation tanks do not completely settle nickel precipitates with high suspended solids, resulting in low removal efficiency, unstable physicochemical effluent, and easy for nickel to exceed the standard. Utility Model Content

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology.

[0004] To achieve the above objectives, this utility model provides a pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology. The device includes a reaction zone, a first precipitation zone, a second precipitation zone, and a setback zone. The reaction zone is used for alkaline adjustment and precipitation treatment of the wastewater. The first precipitation zone is used for primary precipitation treatment of the wastewater that has undergone alkaline adjustment and precipitation pretreatment. The second precipitation zone is used for secondary precipitation treatment of the wastewater that has undergone primary precipitation treatment. The setback zone is used for acid-base neutralization treatment of the wastewater that has undergone secondary precipitation treatment.

[0005] Preferably, the reaction zone includes an alkali adjustment tank, a chelation tank, a PAC tank, and a PAM tank. The alkali adjustment tank is used to add alkaline reagents to the wastewater to adjust the pH. The chelation tank is used to add chelating heavy precipitants to the pH-adjusted wastewater to form chelated nickel precipitates. The PAC tank is used to rapidly coagulate the wastewater after the chelated nickel precipitates have precipitated. The PAM tank is used to flocculate and settle the rapidly coagulated wastewater.

[0006] Preferably, the alkali adjustment tank is connected to the chelation tank, the chelation tank is connected to the PAC tank, the PAC tank is connected to the PAM tank, and the PAM tank is connected to the first sedimentation zone.

[0007] Preferably, the first sedimentation zone includes a first cavity, a vertical pipe disposed in the first cavity, and a reflector plate used in conjunction with the vertical pipe. The reflector plate is disposed on the inner wall of the first cavity and is located below the vertical pipe. The end of the vertical pipe near the reflector plate is provided with a flared opening, and a guide pipe is connected between the vertical pipe and the PAM pool.

[0008] Preferably, the reflector plate penetrates the inner wall of the first cavity.

[0009] Preferably, a first sedimentation space is provided at the bottom of the first cavity, and the first sedimentation space is funnel-shaped, wider at the top and narrower at the bottom.

[0010] Preferably, the second sedimentation zone includes a second cavity, an inclined tube disposed in the second cavity, and an inclined plate used in conjunction with the inclined tube. The inclined plate is disposed on the inner wall of the second cavity, and the inclined tube and the inclined plate are inclined relative to the second cavity. The first cavity is in communication with the inclined tube.

[0011] Preferably, multiple inclined plates are provided, and the multiple inclined plates are spaced apart along the length direction of the second cavity, and the multiple inclined plates are located below the inclined tube.

[0012] Preferably, a second sedimentation space is provided at the bottom of the second cavity, and the second sedimentation space is funnel-shaped, wider at the top and narrower at the bottom.

[0013] Preferably, the callback area includes a callback pool and a clean water pool connected to the callback pool, and a water valve is connected between the callback pool and the clean water pool.

[0014] The beneficial effects of this invention are as follows: chelated nickel precipitates are separated by reaction, and the composite precipitation treatment of the first and second precipitation zones can comprehensively, efficiently and stably remove nickel-containing pollutants, ensuring continuous and stable effluent quality to meet standard requirements. Attached Figure Description

[0015] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0016] Figure 1 This is a top view of the structure of this utility model.

[0017] Figure 2 For the present utility model Figure 1 A schematic diagram of the cross-sectional structure of AA.

[0018] The reference numerals in the figures include: 1—Reaction Zone; 11—Alkali Adjustment Tank; 12—Chelation Tank 13 - PAC pool 14 - PAM pool 2—First sedimentation zone; 21—First cavity; 22—Vertical pipe 23 - Reflector 24 - Horn Mouth 25 - Guide Pipe 26—First Sedimentation Space 3—Second sedimentation zone; 31—Second cavity; 32—Inclined tube 33—Inclined plate; 34—Second sedimentation space 4——Callback Zone 41——Callback Pool 42——Clear Water Pool. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figures 1 to 2 As shown, this utility model discloses a pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology. The device includes a reaction zone 1, a first precipitation zone 2, a second precipitation zone 3, and a setback zone 4. The reaction zone 1 is used for alkalinity adjustment and precipitation treatment of the wastewater. The first precipitation zone 2 is used for primary precipitation treatment of the wastewater that has undergone alkalinity adjustment and precipitation pretreatment. The second precipitation zone 3 is used for secondary precipitation treatment of the wastewater that has undergone primary precipitation treatment. The setback zone 4 is used for acid-base neutralization treatment of the wastewater that has undergone secondary precipitation treatment.

[0022] In wastewater treatment, nickel-containing wastewater enters reaction zone 1 for alkaline adjustment and precipitation treatment. The wastewater pH is adjusted to alkaline, generating Ni(OH)₂ precipitate. However, alkaline adjustment alone is insufficient to completely break the complex and destroy the bond between nickel ions and the complexing agent. Some nickel ions remain stably complexed by the complexing agent, hindering precipitate formation and resulting in low removal efficiency. To address this, a chelating heavy metal precipitant needs to be creatively added. This helps promote the complete precipitation of the remaining nickel ions, effectively replacing the single alkaline adjustment method and thoroughly removing hydrogen and oxygen. The process involves precipitating nickel heavy metals using alkali adjustment as an aid, along with the addition of chelating heavy metal precipitants to promote the formation of stable chelated nickel precipitates for smooth precipitation. The wastewater then undergoes primary precipitation in the first precipitation zone 2 and secondary precipitation in the second precipitation zone 3. This two-stage, deep precipitation treatment efficiently removes and separates large particles, highly suspended solids, small particles, and micro-dust particles, significantly improving precipitation efficiency far superior to single-stage precipitation treatments. This composite precipitation treatment ensures stable effluent and excellent separation results. Finally, acid (such as...) is precisely added in the recovery zone 4. H2SO4, HCl) or alkali (such as H2SO4, HCl) or bases (such as H2SO4, HCl) NaOH and Na2CO3 are used to adjust the pH of the precipitated wastewater back to neutral or the target range, typically 6.5–8.0, providing a standard pH for wastewater reuse or discharge, thus preventing corrosion and scaling of the environment or equipment. This invention uses reaction separation to precipitate chelated nickel precipitates, combined with a composite precipitation treatment in the first precipitation zone 2 and the second precipitation zone 3, to comprehensively, efficiently, and stably remove nickel-containing pollutants, ensuring continuous and stable effluent quality to meet standard requirements.

[0023] In this embodiment, reaction zone 1 includes an alkali adjustment tank 11, a chelation tank 12, a PAC tank 13, and a PAM tank 14. The alkali adjustment tank 11 is used to add alkaline reagents to the wastewater to adjust its pH. The chelation tank 12 is used to add a chelating agent to the pH-adjusted wastewater to form chelated nickel precipitates. The PAC tank 13 is used for rapid coagulation of the wastewater after the chelated nickel precipitates have formed. The PAM tank 14 is used for flocculation and sedimentation of the rapidly coagulated wastewater. Specifically, nickel-containing wastewater enters the alkali adjustment tank 11. Alkaline reagents (such as NaOH, Ca(OH)2, MgO, etc.) are added to adjust the pH of the wastewater, causing nickel metal ions or other soluble components to form insoluble hydroxides or salt precipitates under alkaline conditions. Then, a chelating agent is added to form chelated nickel precipitates, which precipitate out and react with Ni... 2+ Ions form a hydrophobic chelate precipitate, achieving solid-liquid separation. At 25°C, the solubility product of nickel hydroxide, Ksp, ≈ 5.48 × 10⁻⁶. -16Among them, dithiocarbamates (DTCs) are highly efficient heavy metal chelating agents, and they react with Ni... 2+ A hydrophobic chelate precipitate is formed, and its chemical reaction formula is as follows: The solubility product of DTC-Ni chelate is significantly lower than that of Ni(OH)2, resulting in more thorough and complete precipitation. This promotes a very low level of residual nickel ions dissolved in water, ensuring stable compliance with standards and achieving strong chelation of nickel metal ions. Subsequently, PAC tank 13 rapidly coagulates the wastewater from which the chelated nickel precipitate has been released. PAC is first added to complete rapid coagulation. The colloidal particles in the wastewater are negatively charged, and the aluminum ions in PAC can compress their double electric layer, reducing the repulsive force between particles and making them easier to aggregate. Then, anionic PAM is added for flocculation and sedimentation. The PAM molecular chain has amide or ionic groups, which can generate charge interactions with the surface of suspended particles, causing the particles to aggregate into large flocs. The flexibility of the polymer chain allows the flocs to sweep in the water flow, capturing more fine particles, increasing the sedimentation rate, and facilitating subsequent sedimentation treatment.

[0024] In this embodiment, the alkali conditioning tank 11 is connected to the chelation tank 12, the chelation tank 12 is connected to the PAC tank 13, the PAC tank 13 is connected to the PAM tank 14, and the PAM tank 14 is connected to the first sedimentation zone 2. Specifically, the connection between the alkali conditioning tank 11 and the chelation tank 12 facilitates the smooth entry of wastewater after alkali conditioning into the chelation tank 12. The connection between the chelation tank 12 and the PAC tank 13 facilitates the smooth entry of wastewater after the precipitation of chelated nickel into the PAC tank 13. The connection between the PAC tank 13 and the PAM tank 14 facilitates the smooth entry of wastewater after rapid coagulation into the PAM tank 14. The connection between the PAM tank 14 and the first sedimentation zone 2 facilitates the smooth entry of wastewater after flocculation and sedimentation into the first sedimentation zone 2 for primary sedimentation treatment. The structure is compact and the design is reasonable.

[0025] The first sedimentation zone 2 in this embodiment includes a first cavity 21, a vertical pipe 22 disposed in the first cavity 21, and a reflector 23 used in conjunction with the vertical pipe 22. The reflector 23 is disposed on the inner wall of the first cavity 21 and is located below the vertical pipe 22. A flared mouth 24 is provided at one end of the vertical pipe 22 near the reflector 23. A guide pipe 25 is connected between the vertical pipe 22 and the PAM pool 14. Specifically, the wastewater after flocculation and sedimentation enters the vertical pipe 22 through the guide pipe 25, and then pours downward through the vertical pipe 22 and impacts the reflector plate 23. In the vertical flow sedimentation tank, the reflector plate 23 can guide the eddy spray of the wastewater to the inner wall of the first cavity 21, change the flow direction of the wastewater, and prevent the wastewater from directly impacting the bottom or inner wall of the first cavity 21. Since the bell mouth 24 is set at the end of the vertical pipe 22, the bell mouth 24 increases the cross-sectional area of ​​the pipe. According to the formula for calculating liquid flow velocity: flow velocity V = flow rate Q / pipe cross-sectional area A, the flow velocity of the wastewater is slowed down, the residence time of the wastewater on the reflector plate 23 is extended, the solid-liquid separation rate is further improved, uniform sedimentation is promoted, and the turbidity of the effluent is reduced.

[0026] In this embodiment, the reflector 23 penetrates the inner wall of the first cavity 21. Specifically, the reflector 23 penetrates the inner wall of the first cavity 21, that is, the reflector 23 is arranged laterally on both sides of the inner wall of the first cavity 21, increasing the contact area with wastewater, so that the wastewater forms a uniform flow field in the first cavity 21, avoiding the formation of sedimentation dead zones, and improving sedimentation efficiency and reaction contact rate. The reflector 23 is generally made of plastic (such as polypropylene), fiberglass, etc., with a smooth surface that is not easy to adhere to dirt, which is conducive to the sliding of suspended solids. These materials have the advantages of corrosion resistance, light weight, and easy installation.

[0027] In this embodiment, a first sedimentation space 26 is provided at the bottom of the first cavity 21. The first sedimentation space 26 is funnel-shaped, wider at the top and narrower at the bottom. Specifically, the funnel-shaped first sedimentation space 26 increases the sedimentation area. By shortening the sedimentation distance of suspended matter, the funnel-shaped first sedimentation space 26 accelerates the separation of impurities, shortens the sedimentation time, and improves the sedimentation efficiency.

[0028] The second precipitation zone 3 in this embodiment includes a second cavity 31, an inclined tube 32 disposed in the second cavity 31, and an inclined plate 33 used in conjunction with the inclined tube 32. The inclined plate 33 is disposed on the inner wall of the second cavity 31. The inclined tube 32 and the inclined plate 33 are inclined relative to the second cavity 31. The first cavity 21 is connected to the inclined tube 32. Specifically, since the first chamber 21 is connected to the inclined tube 32, and the inclined tube 32 and inclined plate 33 are set at an inclination relative to the second chamber 31, the wastewater that has undergone primary sedimentation treatment enters the second chamber 31 along the inclined tube 32. The wastewater flows from top to bottom, further improving the sedimentation efficiency. The sludge is concentrated at the bottom of the second chamber 31. By eliminating the single sedimentation tank, the problems of poor removal effect, low interception efficiency, some precipitated substances still floating out with the water flow, unstable effluent, and difficulty in controlling effluent quality are effectively solved. Now, a composite sedimentation tank with vertical flow and inclined tube 32 sedimentation is used. On the one hand, the vertical flow at the front of the composite sedimentation tank can remove and separate most of the large particles and highly suspended solids. On the other hand, the remaining small particles and micro-dust particles are removed by the inclined tube 32 sedimentation at the back of the composite sedimentation tank. The overall combination greatly increases the sedimentation efficiency, which is far superior to that of a single sedimentation tank. This composite sedimentation tank can ensure stable effluent and significant separation effect.

[0029] In this embodiment, multiple inclined plates 33 are provided, spaced apart along the length of the second cavity 31, and located below the inclined tube 32. Specifically, the multiple inclined plates 33 spaced apart along the length of the second cavity 31 and located below the inclined tube 32 not only help to form a uniform water flow layer during the flushing of the multiple inclined plates 33, avoiding the formation of local flushing dead zones, but also allow suspended particles to settle along the longer path of the inclined plates 33, reducing the turbidity of the effluent.

[0030] In this embodiment, a second sedimentation space 34 is provided at the bottom of the second cavity 31. The second sedimentation space 34 is funnel-shaped, wider at the top and narrower at the bottom. Specifically, the funnel-shaped second sedimentation space 34 increases the sedimentation area. By shortening the sedimentation distance of suspended matter, the funnel-shaped second sedimentation space 34 accelerates the separation of impurities, shortens the sedimentation time, and improves the sedimentation efficiency.

[0031] In this embodiment, the return zone 4 includes a return tank 41 and a clear water tank 42 connected to the return tank 41. A water valve connects the return tank 41 and the clear water tank 42. Specifically, wastewater that has undergone secondary sedimentation treatment enters the return tank 41. Through a series of operations, the treated water quality is made more stable to meet discharge standards. Filtration is the most basic and common treatment method, which can remove suspended particulate matter and soluble solids from the water through different filter media. Reverse osmosis uses high pressure to pass water through a membrane to remove ions, organic matter, etc. from the water. Electrolysis uses electrical energy to precipitate dissolved ions in the water onto the anode and cathode. Oxidation uses chemical oxidants to oxidize and decompose organic pollutants in the water into harmless substances. The treatment agent in the return tank 41 must be maintained at an appropriate concentration and dosage to ensure the treatment effect. At the same time, the return tank 41 also needs to be cleaned and maintained regularly. Since there is a water valve connecting the return tank 41 and the clear water tank 42, the clear water in the clear water tank 42 can be conveniently used to clean the return tank 41 by opening or closing the water valve, so as to ensure the long-term stable operation of the equipment and the water purification effect. The quality of the effluent must be monitored and tested to promptly detect and solve problems such as equipment failure and substandard effluent.

[0032] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology, characterized in that: It includes a reaction zone, a first sedimentation zone, a second sedimentation zone, and a setback zone. The reaction zone is used for alkaline adjustment and precipitation treatment of wastewater. The first sedimentation zone is used for primary sedimentation treatment of wastewater that has undergone alkaline adjustment and precipitation pretreatment. The second sedimentation zone is used for secondary sedimentation treatment of wastewater that has undergone primary sedimentation treatment. The setback zone is used for acid-base neutralization treatment of wastewater that has undergone secondary sedimentation treatment.

2. The pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 1, characterized in that: The reaction zone includes an alkali adjustment tank, a chelation tank, a PAC tank, and a PAM tank. The alkali adjustment tank is used to add alkaline reagents to the wastewater to adjust the pH. The chelation tank is used to add chelating heavy precipitants to the pH-adjusted wastewater to form chelated nickel precipitates. The PAC tank is used to rapidly coagulate the wastewater after the chelated nickel precipitates have precipitated. The PAM tank is used to flocculate and settle the rapidly coagulated wastewater.

3. The pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 2, characterized in that: The alkali adjustment tank is connected to the chelation tank, the chelation tank is connected to the PAC tank, the PAC tank is connected to the PAM tank, and the PAM tank is connected to the first sedimentation zone.

4. The pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 3, characterized in that: The first sedimentation zone includes a first cavity, a vertical pipe disposed in the first cavity, and a reflector plate used in conjunction with the vertical pipe. The reflector plate is disposed on the inner wall of the first cavity and is located below the vertical pipe. The end of the vertical pipe near the reflector plate is provided with a flared mouth. A guide pipe is connected between the vertical pipe and the PAM pool.

5. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 4, characterized in that: The reflector plate penetrates the inner wall of the first cavity.

6. The pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 5, characterized in that: The bottom of the first cavity is provided with a first sedimentation space, which is funnel-shaped with a wider top and a narrower bottom.

7. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 4, characterized in that: The second sedimentation zone includes a second cavity, an inclined tube disposed in the second cavity, and an inclined plate used in conjunction with the inclined tube. The inclined plate is disposed on the inner wall of the second cavity. The inclined tube and the inclined plate are inclined relative to the second cavity. The first cavity is connected to the inclined tube.

8. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 7, characterized in that: Multiple inclined plates are provided, and the multiple inclined plates are spaced apart along the length direction of the second cavity, and the multiple inclined plates are located below the inclined tube.

9. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 7, characterized in that: The bottom of the second cavity is provided with a second sedimentation space, which is funnel-shaped with a wider top and a narrower bottom.

10. A pretreatment device for treating nickel-containing wastewater from anodizing using chelation separation and composite precipitation technology according to claim 1, characterized in that: The callback area includes a callback pool and a clear water pool connected to the callback pool, and a water valve is connected between the callback pool and the clear water pool.

Images