Chemical nickel plating wastewater treatment and nickel and phosphorus resourceful treatment device

Abstract

The utility model provides a chemical nickel plating wastewater treatment and nickel and phosphorus resourceful treatment device which is characterized by comprising an oxidation unit, a phosphorus recovery unit and a nickel recovery unit, the oxidation unit comprises a reaction tank; the phosphorus recovery unit consists of a first reaction tank, a second reaction tank and a first sedimentation tank; and the nickel recovery unit consists of a third reaction tank, a fourth reaction tank and a second sedimentation tank. A water inlet pipe is arranged at the lower part of the reaction tank; a first dosing pipe and a second dosing pipe are arranged at the top of the reaction tank; a blow-down pipe is arranged at the bottom of the reaction tank; and baffle plates are sequentially and alternately arranged up and down in the reaction tank. According to the utility model, resource utilization of phosphorus and nickel can be realized on the basis of realizing that all indexes of treated effluent reach the standard.

Description

Technical Field

[0001] The utility model relates to a wastewater treatment and resource utilization device, and more specifically, to a chemical nickel plating wastewater treatment and nickel and phosphorus resource utilization device. Background Technique

[0002] In the chemical nickel plating process, the precise dosing of core chemicals is a crucial step to ensure the quality of the coating. These chemicals mainly include nickel sulfate and nickel chloride as nickel sources, hypophosphite as a reducing agent, ammonia water for finely regulating the stability of the plating solution pH value, and organic complexing agents, which significantly improve the long-term stability and service life of the plating solution by forming stable complexes with nickel ions. However, this series of complex chemical reaction processes also lead to the extreme complexity of the composition of chemical nickel plating wastewater. The wastewater not only contains high concentrations of complexed nickel ions but also is rich in ammonia nitrogen, total phosphorus, and various organic substances. These components are intertwined, increasing the challenge of wastewater treatment. Given the high complexity of the wastewater, traditional single treatment processes often struggle to comprehensively and effectively remove all pollutants and achieve ideal treatment effects. Therefore, for the treatment of chemical nickel plating wastewater, an integrated treatment strategy is required, which may include the organic combination of physicochemical methods (such as coagulation precipitation, adsorption, ion exchange, etc.) and biological treatment technologies, and even the introduction of new technologies such as advanced oxidation to achieve targeted removal and deep purification of different pollutants.

[0003] At present, the common strategies for the treatment of electroless nickel plating wastewater cover various technical approaches such as chemical precipitation, redox, electrolysis, ion exchange, and adsorption. However, these traditional methods generally face a common problem: most of them focus on the removal of a single pollutant and it is difficult to ensure that the three key indicators of total nickel, ammonia nitrogen, and total phosphorus all meet the standards simultaneously to meet the strict limits in Table 3 of GB21900-2008 "Discharge Standard for Pollutants from Electroplating". More regrettably, these methods often neglect the potential for the recycling and reuse of valuable resources such as phosphorus and nickel in the wastewater, resulting in unnecessary resource waste. Specifically in some patent technology cases (such as CN 209583854U, CN 105384298 B, CN 111039441 A, and CN112607893 A), although they have technological innovations, their process flows are complex and they fail to achieve the feasibility of efficient nickel and phosphorus resource recovery in practical applications. In addition, these technologies also fail to fully meet the more stringent discharge standards in specific regions, such as the strict limits on total nickel (<0.3mg / L) and ammonia nitrogen (<15mg / L) in the "Discharge Standard for Water Pollutants from Electroplating in Zhejiang Province" (DB33 / 2260-2020), and the strict requirements for total phosphorus (<8mg / L) in the "Indirect Discharge Limits for Nitrogen and Phosphorus Pollutants in Industrial Enterprises' Wastewater" (DB33 / 887-2013). Therefore, in order to overcome the above challenges, there is an urgent need to develop a more comprehensive and efficient wastewater treatment and resource recovery technology system. Such a system should be able to treat multiple pollutants simultaneously, ensure that all discharge indicators meet the standards, and effectively recover resources such as nickel and phosphorus in the wastewater, achieving a win-win situation for economic and environmental benefits. Summary of the Invention

[0004] To solve the above technical problems, the present utility model provides a device for treating electroless nickel plating wastewater and recycling nickel and phosphorus, adopting the following technical solutions:

[0005] A device for treating electroless nickel plating wastewater and recycling nickel and phosphorus, characterized in that it includes an oxidation unit, a phosphorus recovery unit, and a nickel recovery unit; the oxidation unit includes a reaction tank; the phosphorus recovery unit consists of a first reaction tank, a second reaction tank, and a first sedimentation tank; the nickel recovery unit consists of a third reaction tank, a fourth reaction tank, and a second sedimentation tank.

[0006] Furthermore, a water inlet pipe is provided at the lower part of the reaction tank; a first chemical addition pipe and a second chemical addition pipe are provided at the top of the reaction tank; a drain pipe is provided at the bottom of the reaction tank; and baffle plates are alternately arranged up and down inside the reaction tank.

[0007] Further, a third chemical addition pipe and a fourth chemical addition pipe are provided at the top of the first reaction tank, a fifth chemical addition pipe is provided at the top of the second reaction tank, a sixth chemical addition pipe is provided at the top of the third reaction tank, and a seventh chemical addition pipe is provided at the top of the fourth reaction tank.

[0008] Further, stirrers and pH on-line monitors are provided in the reaction tank, the first reaction tank and the third reaction tank, stirrers are provided in the second reaction tank and the fourth reaction tank, and sludge discharge pipes are provided at the bottoms of the first sedimentation tank and the second sedimentation tank.

[0009] Further, a first overflow pipe is provided between the oxidation unit and the phosphorus recovery unit, and a second overflow pipe is provided between the phosphorus recovery unit and the nickel recovery unit.

[0010] Further, a water outlet pipe is provided at the upper part of the second sedimentation tank.

[0011] Compared with the prior art, the advantages of the utility model are as follows:

[0012] (1) This device stands out with its excellent convenience in operation, environmental friendliness and the advantage of no secondary pollution, ensuring that the effluent water quality meets the standards stably. Specifically, the total nickel concentration is strictly controlled below 0.3 mg / L, the total phosphorus is below 8 mg / L, and the ammonia nitrogen content does not exceed 15 mg / L, fully meeting the stringent discharge standards.

[0013] (2) This device not only effectively treats wastewater, but also converts waste into valuable resources. Through the resource recovery of nickel and phosphorus, it actively responds to the national "dual carbon" strategic goal and promotes green and sustainable development.

[0014] (3) To achieve the precise dosing and efficient utilization of chemicals, this device innovatively introduces an on-line pH meter to intelligently control the acid / alkali pump, ensuring precise control of the pH value. At the same time, the dosing amounts of sodium hypochlorite and ferric chloride are dynamically adjusted according to the real-time monitoring data of the total phosphorus, ammonia nitrogen and total phosphorus content in the wastewater, effectively avoiding excessive dosing of chemicals and reducing cost waste.

[0015] (4) In the nickel and phosphorus recovery links, this device makes full use of the chemical properties of iron phosphate and nickel hydroxide, and carefully designs the recovery sequence of phosphorus first and then nickel. This strategy greatly reduces the number of pH adjustments, simplifies the treatment process and improves the overall treatment efficiency.

[0016] (5) This device realizes high-value conversion in the recovery and utilization of phosphorus. Compared with traditional phosphate fertilizers, gypsum and other materials, iron phosphate gives new life and value-added space to the recovered materials due to its wide application prospects and higher economic value.

[0017] (6) The device is designed flexibly, easy for modular and standardized production and rapid replication and deployment, capable of flexibly meeting the electroless nickel plating wastewater treatment requirements of different scales and characteristics, showing strong adaptability and economic practicality, and providing users with a more convenient, efficient and economical wastewater treatment solution. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the present utility model.

[0019] Wherein 1 is the oxidation unit, 2 is the phosphorus recovery unit, 3 is the nickel recovery unit, 4 is the reaction tank, 5 is the first reaction tank, 6 is the second reaction tank, 7 is the first sedimentation tank, 8 is the third reaction tank, 9 is the fourth reaction tank, 10 is the second sedimentation tank, 11 is the water inlet pipe, 12 is the first chemical addition pipe, 13 is the second chemical addition pipe, 14 is the vent pipe, 15 is the baffle plate, 16 is the third chemical addition pipe, 17 is the fourth chemical addition pipe, 18 is the fifth chemical addition pipe, 19 is the sixth chemical addition pipe, 20 is the seventh chemical addition pipe, 21 is the stirrer, 22 is the pH on-line monitor, 23 is the sludge discharge pipe, 24 is the first overflow pipe, 25 is the second overflow pipe, 26 is the water outlet pipe. Detailed Embodiments

[0020] The following further elaborates and explains the present utility model in conjunction with the drawings and detailed embodiments.

[0021] As Figure 1 shown, a device for treating electroless nickel plating wastewater and recycling nickel and phosphorus provided by the present utility model includes an oxidation unit 1, a phosphorus recovery unit 2, a nickel recovery unit 3, a reaction tank 4, a first reaction tank 5, a second reaction tank 6, a first sedimentation tank 7, a third reaction tank 8, a fourth reaction tank 9, a second sedimentation tank 10, a water inlet pipe 11, a first chemical addition pipe 12, a second chemical addition pipe 13, a vent pipe 14, a baffle plate 15, a third chemical addition pipe 16, a fourth chemical addition pipe 17, a fifth chemical addition pipe 18, a sixth chemical addition pipe 19, a seventh chemical addition pipe 20, a stirrer 21, a pH on-line monitor 22, a sludge discharge pipe 23, a first overflow pipe 24, a second overflow pipe 25, and a water outlet pipe 26.

[0022] The device includes an oxidation unit 1, a phosphorus recovery unit 2 and a nickel recovery unit 3; the oxidation unit 1 includes a reaction tank 4; the phosphorus recovery unit 2 is composed of a first reaction tank 5, a second reaction tank 6 and a first sedimentation tank 7; the nickel recovery unit 2 is composed of a third reaction tank 8, a fourth reaction tank 9 and a second sedimentation tank 10.

[0023] The lower part of the reaction tank 4 is provided with a water inlet pipe 11; the top of the reaction tank 4 is provided with a first chemical addition pipe 12 and a second chemical addition pipe 13; the bottom of the reaction tank 4 is provided with a vent pipe 14; and the inside of the reaction tank 4 is provided with baffle plates 15 alternately arranged up and down.

[0024] A third chemical addition pipe 16 and a fourth chemical addition pipe 17 are provided at the top of the first reaction tank 5, and a fifth chemical addition pipe 18 is provided at the top of the second reaction tank 6; a sixth chemical addition pipe 19 is provided at the top of the third reaction tank 8; a seventh chemical addition pipe 20 is provided at the top of the fourth reaction tank 9.

[0025] Agitators 21 and pH on-line monitors 22 are provided in the reaction tank 4, the first reaction tank 5 and the third reaction tank 8; agitators 21 are provided in the second reaction tank 6 and the fourth reaction tank 9; sludge discharge pipes 23 are provided at the bottoms of the first sedimentation tank 7 and the second sedimentation tank 10.

[0026] A first overflow pipe 24 is provided between the oxidation unit 1 and the phosphorus recovery unit 2; a second overflow pipe 25 is provided between the phosphorus recovery unit 2 and the nickel recovery unit 3.

[0027] A water outlet pipe 26 is provided at the upper part of the second sedimentation tank 10.

[0028] The working principle of this device is as follows:

[0029] Oxidation unit: Wastewater enters the reaction tank through the inlet pipe, sodium hypochlorite enters the reaction tank through the first chemical addition pipe, and sulfuric acid or hydrochloric acid solution enters the reaction tank through the second chemical addition pipe. In the reaction tank, sodium hypochlorite removes ammonia nitrogen in the wastewater through breakpoint reaction; sodium hypochlorite oxidizes non-orthophosphate in the wastewater into orthophosphate by its own oxidizing property, and at the same time oxidizes complex nickel, converting complex nickel into ionic nickel.

[0030] Phosphorus recovery unit: The effluent from the oxidation unit enters the first reaction tank through the first overflow pipe, ferric chloride solution enters the first reaction tank through the third chemical addition pipe, and sulfuric acid or hydrochloric acid solution enters the first reaction tank through the fourth chemical addition pipe. In the first reaction tank, ferric ions and orthophosphate react with each other to form tiny suspended iron phosphate particles; the effluent from the first reaction tank enters the second reaction tank, and polyacrylamide solution enters the second reaction tank through the fifth chemical addition pipe. In the second reaction tank, the tiny suspended iron phosphate particles are aggregated into large iron phosphate particles that are easy to precipitate through the flocculation of polyacrylamide; the effluent from the second reaction tank enters the first sedimentation tank to complete the separation of iron phosphate sludge and wastewater. The iron phosphate precipitated sludge is discharged into the sludge tank through the sludge discharge pipe, and the sludge is lifted to a plate and frame filter press by a sludge pump for pressure filtration. After pressure filtration, the iron phosphate sludge is dried to obtain a dry iron phosphate product.

[0031] Nickel recovery unit: the effluent from the first sedimentation tank enters the third reaction tank, the sodium hydroxide solution enters the third reaction tank through the sixth dosing pipe, and the ionic nickel can react with hydroxide to form tiny suspended nickel hydroxide particles; the effluent from the third reaction tank enters the fourth reaction tank, and the polyacrylamide enters the fourth reaction tank through the seventh dosing pipe, and the tiny suspended nickel hydroxide particles are aggregated into easily precipitated nickel hydroxide particles through the flocculation effect of polyacrylamide; the effluent from the fourth reaction tank enters the second sedimentation tank to complete the separation of nickel hydroxide sludge and wastewater. The treated effluent is discharged through the outlet pipe, and the nickel hydroxide sludge is discharged from the sludge discharge pipe into the sludge tank, and is lifted to the plate and frame filter press by the sludge pump for filtration. After filtration, the nickel hydroxide sludge is dried to obtain a dry nickel hydroxide product.

[0032] The traditional treatment method for chemical nickel plating wastewater is difficult to ensure that the three key indicators of total nickel, ammonia nitrogen and total phosphorus meet the standards at the same time, and ignores the recycling potential of valuable resources such as phosphorus and nickel in the wastewater, so its application has limitations. The utility model can achieve resource utilization of phosphorus and nickel on the basis of achieving full standards of treated effluent. Example

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments.

[0034] like Figure 1 As shown, this project adopts the above technical solution to trial-produce a chemical nickel plating wastewater treatment and nickel and phosphorus resource treatment device, and the treatment object is chemical nickel plating wastewater.

[0035] The device comprises an oxidation unit 1, a phosphorus recovery unit 2 and a nickel recovery unit 3; the oxidation unit 1 comprises a reaction tank 4; the phosphorus recovery unit 2 comprises a first reaction tank 5, a second reaction tank 6 and a first precipitation tank 7; the nickel recovery unit 2 comprises a third reaction tank 8, a fourth reaction tank 9 and a second precipitation tank 10.

[0036] A water inlet pipe 11 is provided at the lower part of the reaction tank 4; a first chemical addition pipe 12 and a second chemical addition pipe 13 are provided at the top of the reaction tank 4; a drain pipe 14 is provided at the bottom of the reaction tank 4; baffle plates 15 are alternately arranged up and down inside the reaction tank 4. A third chemical addition pipe 16 and a fourth chemical addition pipe 17 are provided at the top of the first reaction tank 5, a fifth chemical addition pipe 18 is provided at the top of the second reaction tank 6; a sixth chemical addition pipe 19 is provided at the top of the third reaction tank 8; a seventh chemical addition pipe 20 is provided at the top of the fourth reaction tank 9. Stirrers 21 and pH on-line monitors 22 are provided in the reaction tank 4, the first reaction tank 5 and the third reaction tank 8; stirrers 21 are provided in the second reaction tank 6 and the fourth reaction tank 9; sludge discharge pipes 23 are provided at the bottoms of the first sedimentation tank 7 and the second sedimentation tank 10. A first overflow pipe 24 is provided between the oxidation unit 1 and the phosphorus recovery unit 2; a second overflow pipe 25 is provided between the phosphorus recovery unit 2 and the nickel recovery unit 3. An outlet water pipe 26 is provided at the upper part of the second sedimentation tank 10.

[0037] This device is used for treating electroless nickel plating wastewater in a certain electroplating wastewater treatment plant in Ningbo. The total nickel concentration in the electroless nickel plating wastewater is about 1000 mg / L, the total phosphorus concentration is about 8000 mg / L, and the ammonia nitrogen concentration is about 100 mg / L. After being treated by the inventive device, the effluent water quality is shown in Table 1, and the sludge content analysis is shown in Table 2.

[0038] Table 1 Effluent water quality

[0039] Table 2 Sludge content analysis

[0040] It can be seen from Table 1 that after treating the electroless nickel plating wastewater with this device, the total nickel concentration in the effluent water quality is less than 0.3 mg / L, the total phosphorus is less than 8 mg / L, and the ammonia nitrogen is less than 15 mg / L, meeting the discharge requirements. It can be seen from Table 2 that after the wastewater is treated by the device, the nickel ions in the wastewater are converted into nickel hydroxide. According to the detection method in the national standard GB / T20507-2018, the nickel hydroxide content is 90-95%, which can be directly reused, realizing the recycling of nickel ions in the wastewater; the total phosphorus in the wastewater is converted into iron phosphate. According to the detection method in the standard HG / T4701-2014, the content of iron phosphate is about 98.0%-99.8%. A small amount of impurities do not meet the requirements of the iron phosphate for batteries. Battery-grade iron phosphate can be obtained through impurity removal. Through this scheme, an iron phosphate primary product can be formed, realizing the recycling of phosphorus in the wastewater.

[0041] The above-described embodiments are only used to illustrate one implementation manner of the present utility model, rather than limiting it. It should be noted that those of ordinary skill in the art can modify the technical solutions recorded in the above embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present utility model.

Claims

1. A device for treating chemical nickel plating wastewater and recycling nickel and phosphorus, characterized in that: It comprises an oxidation unit, a phosphorus recovery unit and a nickel recovery unit; the oxidation unit comprises a reaction tank; the phosphorus recovery unit consists of a first reaction tank, a second reaction tank and a first precipitation tank; the nickel recovery unit consists of a third reaction tank, a fourth reaction tank and a second precipitation tank.

2. A chemical nickel plating wastewater treatment and nickel and phosphorus resource treatment device according to claim 1, characterized in that: The lower part of the reaction tank is provided with a water inlet pipe; the top of the reaction tank is provided with a first dosing pipe and a second dosing pipe; the bottom of the reaction tank is provided with a vent pipe; and the inside of the reaction tank is provided with baffles alternately arranged up and down.

3. The device for treating chemical nickel plating wastewater and recycling nickel and phosphorus according to claim 1, characterized in that: The top of the first reaction tank is provided with a third dosing tube and a fourth dosing tube, the top of the second reaction tank is provided with a fifth dosing tube; the top of the third reaction tank is provided with a sixth dosing tube; the top of the fourth reaction tank is provided with a seventh dosing tube.

4. The device for treating chemical nickel plating wastewater and recycling nickel and phosphorus according to claim 1, characterized in that: The reaction tank, the first reaction tank and the third reaction tank are each provided with an agitator and a pH online monitor; the second reaction tank and the fourth reaction tank are each provided with an agitator; and the bottom of the first sedimentation tank and the second sedimentation tank are each provided with a mud discharge pipe.

5. The device for treating chemical nickel plating wastewater and recycling nickel and phosphorus according to claim 1, characterized in that: A first flow pipe is arranged between the oxidation unit and the phosphorus recovery unit; and a second flow pipe is arranged between the phosphorus recovery unit and the nickel recovery unit.

6. The device for treating chemical nickel plating wastewater and recycling nickel and phosphorus according to claim 1, characterized in that: A water outlet pipe is provided at the upper portion of the second sedimentation tank.

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