A waste liquid recovery treatment system for a chemical nickel plating bath

Abstract

The utility model discloses a kind of waste liquid recovery treatment systems of chemical nickel plating bath, it is related to the technical field of waste liquid treatment, including sedimentation separation device, electrodeposition recovery device, ion exchange device, oxidation device and evaporative condenser, chemical nickel plating bath is passed into first sedimentation separation pool, first sedimentation separation pool is used for the sedimentation reaction of chemical nickel plating bath and adjusts the pH value of chemical nickel plating bath, pressure filter and clear liquid collection barrel are arranged between first sedimentation separation pool and nickel electrodeposition tank, electrodeposition barren liquid recovery mechanism is used to recover the nickel in the electrodeposition barren liquid discharged in nickel electrodeposition tank;Second sedimentation separation pool, electro-catalytic oxidation tank and three-effect evaporator are sequentially arranged behind electrodeposition barren liquid recovery mechanism.The waste liquid recovery treatment system of chemical nickel plating bath of the utility model can efficiently recover the nickel in bath, and recycle and utilize the phosphorus resource in bath.

Description

Technical Field

[0001] This utility model relates to the technical field of waste liquid treatment, and in particular to a waste liquid recycling and treatment system for electroless nickel plating baths. Background Technology

[0002] Electroless nickel plating solutions typically use nickel sulfate and nickel acetate as main salts, and hypophosphite, sodium borohydride, borane, hydrazine, etc. as reducing agents, with various additives added. The process is carried out in acidic solutions at 90℃ or in neutral or alkaline solutions near room temperature. Depending on the reducing agent used, electroless nickel-phosphorus plating and electroless nickel-boron plating are two main categories. The plating exhibits superior uniformity, corrosion resistance, hardness, solderability, magnetism, and decorative properties.

[0003] After a period of use, electroless nickel plating solutions are disposed of. However, due to their complex composition, containing complexing agents, hypophosphite, pH buffers, and other substances, the complexing agents in the wastewater can combine with nickel ions to form small complex molecules. These complex molecules are relatively stable, making it difficult for nickel ions to precipitate with sodium hydroxide or other heavy metal chelating agents. Therefore, the disposal of electroless nickel plating solutions is very difficult, and companies typically entrust the disposal of the waste solution to a third-party hazardous waste management company.

[0004] Therefore, providing an efficient and environmentally friendly method for recycling chemical nickel plating bath solutions is a technical problem that urgently needs to be solved. Utility Model Content

[0005] The purpose of this invention is to provide a waste liquid recycling and treatment system for electroless nickel plating baths, in order to solve the problems existing in the prior art, and to efficiently recover nickel from the bath and recycle phosphorus resources from the bath.

[0006] To achieve the above objectives, this utility model provides the following solution: This invention provides a waste liquid recycling and treatment system for electroless nickel plating baths, comprising a precipitation separation device, an electrowinning recovery device, an ion exchange device, an oxidation device, and an evaporation and condensation device. The precipitation separation device includes a first precipitation separation tank and a second precipitation separation tank. The electrowinning recovery device includes a nickel electrowinning tank. The ion exchange device includes an electrowinning lean solution recovery mechanism. The oxidation device includes an electrocatalytic oxidation tank. The evaporation and condensation device includes a triple-effect evaporator. The electroless nickel plating bath is fed into the first precipitation separation tank, which is used for the precipitation reaction of the electroless nickel plating bath and to adjust the pH value of the electroless nickel plating bath. A filter press and a clear liquid collection tank are provided between the first precipitation separation tank and the nickel electrowinning tank. The electrowinning lean solution recovery mechanism is used to recover nickel from the electrowinning lean solution discharged from the nickel electrowinning tank. The second precipitation separation tank, the electrocatalytic oxidation tank, and the triple-effect evaporator are sequentially arranged behind the electrowinning lean solution recovery mechanism.

[0007] In one embodiment, the electroless nickel plating bath solution is contained in a raw water tank for electroless nickel plating bath solution, and the raw water tank for electroless nickel plating bath solution is connected to the inlet of the first sedimentation separation tank via a booster pump.

[0008] In one embodiment, a liquid alkali tank is also included, which is used to introduce liquid alkali into the first precipitation separation tank, the nickel electrowinning tank, and the second precipitation separation tank, respectively.

[0009] In one embodiment, the outlet of the liquid alkali tank is provided with a main pipeline and three branch pipelines. One end of the main pipeline is connected to the outlet of the liquid alkali tank, and a liquid pump is installed on the main pipeline. The other end of the main pipeline is connected to the three branch pipelines respectively, and each branch pipeline is provided with a valve.

[0010] In one embodiment, a first plate and frame filter press is provided between the first sedimentation separation tank and the clear liquid collection tank. The first plate and frame filter press is used to perform solid-liquid separation on the water after sedimentation reaction in the first sedimentation separation tank, and the filtrate is discharged to the clear liquid collection tank.

[0011] In one embodiment, the inlet of the nickel electrodeposition cell is located at the lower part of the nickel electrodeposition cell, and the outlet of the nickel electrodeposition cell is located at the upper side of the nickel electrodeposition cell; the nickel electrodeposition cell is equipped with a heating device and a ventilation fan; and an adjustable-flow water pump is installed on the connecting pipeline between the clear liquid collection tank and the nickel electrodeposition cell.

[0012] In one embodiment, the electrowinning lean solution recovery mechanism uses a nickel recovery resin column, the outlet of which is connected to the second precipitation separation tank.

[0013] In one embodiment, the nickel recovery resin column is also connected to a pure water storage tank and a dilute sulfuric acid preparation tank, and the outlet of the nickel recovery resin column is also connected to a nickel-rich desorption liquid collection tank, which is connected to the inlet of the nickel electrowinning cell.

[0014] In one embodiment, a lime slurry storage tank is also included. The lime slurry storage tank is connected to a second sedimentation separation tank. A second plate and frame filter press is provided between the second sedimentation separation tank and the electrocatalytic oxidation tank. The second plate and frame filter press is used to perform solid-liquid separation on the water after sedimentation reaction in the second sedimentation separation tank, and the filtrate is sent into the electrocatalytic oxidation tank.

[0015] In one embodiment, the outlet of the triple-effect evaporator is also connected to a condensate collection tank and a crystallized salt storage tank, respectively.

[0016] The present invention achieves the following technical advantages over the prior art: This invention discloses a waste liquid recovery and treatment system for electroless nickel plating baths, comprising a precipitation separation device, an electrowinning recovery device, an ion exchange device, an oxidation device, and an evaporation and condensation device. The precipitation separation device includes a first precipitation separation tank and a second precipitation separation tank; the electrowinning recovery device includes a nickel electrowinning tank; the ion exchange device includes an electrowinning lean solution recovery mechanism; the oxidation device includes an electrocatalytic oxidation tank; and the evaporation and condensation device includes a triple-effect evaporator. The electroless nickel plating bath solution is fed into the first precipitation separation tank, which is used for the precipitation reaction of the electroless nickel plating bath solution and to adjust the pH value of the solution. A filter press and a clear liquid collection tank are installed between the first precipitation separation tank and the nickel electrowinning tank. The electrowinning lean solution recovery mechanism is used to recover nickel from the lean solution discharged from the nickel electrowinning tank. The second precipitation separation tank, the electrocatalytic oxidation tank, and the triple-effect evaporator are sequentially arranged after the electrowinning lean solution recovery mechanism. This invention's waste liquid recovery and treatment system for electroless nickel plating baths can efficiently recover nickel from the bath solution and recycle phosphorus resources from it. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a waste liquid recovery and treatment system for electroless nickel plating baths; In the diagram: 1. Raw water tank for electroless nickel plating bath; 2. First sedimentation separation tank; 3. Liquid alkali tank; 4. First plate and frame filter press; 5. Clear liquid collection tank; 6. Nickel electrowinning tank; 7. Ventilation fan; 8. Acid mist absorption tank; 9. Nickel recovery resin column; 10. Dilute sulfuric acid preparation tank; 11. Nickel-rich desorption liquid collection tank; 12. Second sedimentation separation tank; 13. Lime solution storage tank; 14. Second plate and frame filter press; 15. Electrocatalytic oxidation tank; 16. Triple-effect evaporator; 17. Condensate collection tank; 18. Pure water storage tank; 19. Crystallized salt storage tank. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] The purpose of this invention is to provide a waste liquid recycling and treatment system for electroless nickel plating baths, in order to solve the problems existing in the prior art, and to efficiently recover nickel from the bath and recycle phosphorus resources from the bath.

[0021] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, this utility model provides a waste liquid recycling system for electroless nickel plating baths, including a precipitation separation device, an electrowinning recovery device, an ion exchange device, an oxidation device, and an evaporation and condensation device. The precipitation separation device includes a first precipitation separation tank 2 and a second precipitation separation tank 12. The electrowinning recovery device includes a nickel electrowinning tank 6. The ion exchange device includes an electrowinning lean liquid recovery mechanism. The oxidation device includes an electrocatalytic oxidation tank 15. The evaporation and condensation device includes a triple-effect evaporator 16. The electroless nickel plating bath is fed into the first precipitation separation tank 2, which is used for the precipitation reaction of the electroless nickel plating bath and to adjust the pH value of the electroless nickel plating bath. A filter press and a clear liquid collection tank 5 are installed between the first precipitation separation tank 2 and the nickel electrowinning tank 6. The electrowinning lean liquid recovery mechanism is used to recover nickel from the electrowinning lean liquid discharged from the nickel electrowinning tank 6. The second precipitation separation tank 12, the electrocatalytic oxidation tank 15, and the triple-effect evaporator 16 are sequentially arranged behind the electrowinning lean liquid recovery mechanism.

[0023] In one embodiment, the electroless nickel plating bath solution is contained in an electroless nickel plating bath solution raw water tank 1, which is connected to the inlet of the first sedimentation separation tank 2 via a booster pump. It also includes a liquid alkali tank 3, which is used to introduce liquid alkali into the first sedimentation separation tank 2, the nickel electrowinning tank 6, and the second sedimentation separation tank 12, respectively. Specifically, the outlet of the liquid alkali tank 3 is provided with a main pipeline and three branch pipelines. One end of the main pipeline is connected to the outlet of the liquid alkali tank 3, and a liquid pump is installed on the main pipeline. The other end of the main pipeline is connected to the three branch pipelines, and each branch pipeline is equipped with a valve. A first plate and frame filter press 4 is installed between the first sedimentation separation tank 2 and the clear liquid collection tank 5. The first plate and frame filter press 4 is used to perform solid-liquid separation on the water after the sedimentation reaction in the first sedimentation separation tank 2, and the filtrate is discharged to the clear liquid collection tank 5.

[0024] The system comprises two sets of precipitation separation devices. The first precipitation separation tank 2 is used to neutralize the electroless nickel plating bath solution with acid and alkali, precipitate impurity ions such as ferric iron and aluminum, and remove suspended solids from the solution. The second precipitation separation tank 12 is used to precipitate phosphate and phosphite ions in the solution using calcium salts to obtain a phosphorus-rich solid product. Both sets of devices consist of a wastewater lift pump, a liquid alkali tank 3, a lime solution storage tank 13, a reagent lift pump, a reaction tank with a stirrer, a pH meter, and a plate and frame filter press. The installation of the lift pump, the reaction tank with a stirrer, and the pH meter are all mature technologies, and conventional settings can meet the usage requirements; therefore, further details are omitted here.

[0025] In one embodiment, the electrowinning recovery device comprises a nickel electrowinning tank 6, an electrowinning solution booster pump, an electrowinning solution heating device, a ventilation fan 7, an acid mist absorption tank 8, and a temperature detector. The main body of the nickel electrowinning tank 6 is made of PVC, with a nickel foam cathode and a titanium-coated lead dioxide anode, and an electrode spacing of 1.5 cm. The function of the nickel electrowinning tank 6 is to directly electrowinet the clarified liquid in the first precipitation separation tank 2 to recover valuable nickel metal; the heating device heats the electrowinning solution to 60-75°C to improve the current efficiency during electrowinning; the acid mist generated during electrowinning is adsorbed by the ventilation fan 7 and discharged into the acid mist absorption tank 8 containing 5% liquid alkali. The inlet of the nickel electrowinning tank 6 is located at the lower part of the nickel electrowinning tank 6, and the outlet of the nickel electrowinning tank 6 is located on the upper side of the nickel electrowinning tank 6; the nickel electrowinning tank 6 is equipped with a heating device and a ventilation fan 7; an adjustable-flow inlet pump is installed on the connecting pipeline between the clarified liquid collection tank 5 and the nickel electrowinning tank 6.

[0026] In one embodiment, the electrowinning solution recovery mechanism uses a nickel recovery resin column 9, the outlet of which is connected to a second precipitation separation tank 12. The nickel recovery resin column 9 is also connected to a pure water storage tank 18 and a dilute sulfuric acid preparation tank 10. The outlet of the nickel recovery resin column 9 is also connected to a nickel-rich desorption solution collection tank 11, which is connected to the inlet of the nickel electrowinning cell 6.

[0027] The ion exchange unit includes a wastewater booster pump, a nickel recovery resin column 9, an acid desorption solution preparation tank, and a pure water tank. The nickel recovery resin column 9 is an ion exchange resin column made of acrylic or fiberglass, filled with 50-70% of its capacity of 432 chelating resin. It is used to treat the lean electrolyte produced by the aforementioned electrowinning recovery unit, deeply recovering nickel from the lean electrolyte. The treated electrolyte is discharged to the second precipitation separation tank 12. After the resin is saturated, the nickel-rich desorption solution generated by desorption is discharged to the electrowinning recovery unit.

[0028] In one embodiment, the oxidation device includes an aerator, an electrocatalytic oxidation tank, and a booster pump. Its function is to oxidize the clarified liquid produced in the second sedimentation separation tank 12, oxidizing residual hypophosphite, phosphite, and some organic matter in the clarified liquid. It also includes a lime slurry storage tank 13, which is connected to the second sedimentation separation tank 12. A second plate and frame filter press 14 is installed between the second sedimentation separation tank 12 and the electrocatalytic oxidation tank 15. The second plate and frame filter press 14 is used to perform solid-liquid separation on the water after the sedimentation reaction in the second sedimentation separation tank 12, and the filtrate is sent to the electrocatalytic oxidation tank 15.

[0029] In one embodiment, the evaporation apparatus comprises various pumps, a steam supply system, and a triple-effect evaporator 16. Its function is to concentrate the effluent from the oxidation system to obtain phosphorus-rich crystalline salt. The outlet of the triple-effect evaporator 16 is also connected to a condensate collection tank 17 and a crystalline salt storage tank 19.

[0030] The treatment method for the waste liquid recovery and treatment system of electroless nickel plating bath includes the following steps: Step 1) Use a booster pump to pass the electroless nickel plating bath solution into the first sedimentation separation tank 2, add liquid alkali into it, adjust the pH to 6.5-7.5, and stir for 30 minutes; Step 2) The water after sedimentation reaction in the first sedimentation separation tank 2 is sent to the first plate and frame filter press 4 for filtration. The filtrate is discharged to the clear liquid collection tank 5. The filter residue is cleaned and unloaded regularly and collected into the electroplating sludge for unified treatment. Step 3) After the clear liquid is fed into the nickel electrodeposition cell 6 from the bottom of the electrodeposition cell, turn on the heating device and the ventilation fan 7. When the temperature of the solution in the cell reaches about 70°C, turn on the power supply of the electrodeposition cell and control the current density to 100A / m2. At the same time, adjust the flow rate of the clear liquid inlet pump so that the clear liquid stays in the cell for 3-4 hours. The overflowing electrodeposition lean liquid is sent to the next device. Step 4) The lean electrolyte solution is fed into the nickel recovery resin column 9 at a flow rate of 5-10 BV / h using a booster pump, and the solution after exchange is sent to the second precipitation separation tank 12. After the resin is saturated, it is washed with pure water and desorbed with 10% sulfuric acid. The desorbed solution is sent to the nickel-rich desorbed solution collection tank, and the desorbed solution in the nickel-rich desorbed solution collection tank is periodically discharged to the nickel electrodeposition tank 6. Step 5) When the liquid level in the second sedimentation separation tank 12 reaches more than 80%, turn on the agitator and add lime slurry to precipitate anions such as phosphite, phosphate, and citrate in the liquid. When the pH of the solution in the tank reaches 9.5, stop adding lime and stir for another hour. Then, send the solution to the second plate and frame filter press 14 and the filtrate to the electrocatalytic oxidation tank 15. The filter residue can be cleaned and unloaded regularly or sold as raw material for phosphate fertilizer and collected into the electroplating sludge for unified treatment. Step 6) Turn on the DC power supply for the electrocatalytic oxidation, control the current density to 200A / m2, and adjust the electrocatalytic oxidation water pump to make the relative residence time of the solution 2h. After the reaction, the solution is discharged to the triple-effect evaporator 16. Step 7) During the evaporation process, the concentration ratio of the liquid is controlled to be 20-25 times to obtain by-product crystalline salt. The condensate is discharged to the condensate storage tank, and after the tank is full, it is discharged into the electroplating general external drainage.

[0031] Because the output of electroless nickel plating bath solutions fluctuates greatly in electroplating enterprises and the supply of raw water to the system is unstable, the system does not need to meet the requirements of continuous treatment. In actual treatment, a single-tank reaction-segmented advancement treatment mode is often adopted.

[0032] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A waste liquid recycling and treatment system for electroless nickel plating baths, characterized in that: The system includes a precipitation separation device, an electrodeposition recovery device, an ion exchange device, an oxidation device, and an evaporation and condensation device. The precipitation separation device includes a first precipitation separation tank and a second precipitation separation tank. The electrodeposition recovery device includes a nickel electrodeposition tank. The ion exchange device includes an electrodeposition lean solution recovery mechanism. The oxidation device includes an electrocatalytic oxidation tank. The evaporation and condensation device includes a triple-effect evaporator. The electroless nickel plating bath solution is fed into the first precipitation separation tank, which is used for the precipitation reaction of the electroless nickel plating bath solution and to adjust the pH value of the electroless nickel plating bath solution. A filter press and a clear liquid collection tank are installed between the first precipitation separation tank and the nickel electrodeposition tank. The electrodeposition lean solution recovery mechanism is used to recover nickel from the electrodeposition lean solution discharged from the nickel electrodeposition tank. The second precipitation separation tank, the electrocatalytic oxidation tank, and the triple-effect evaporator are sequentially arranged behind the electrodeposition lean solution recovery mechanism.

2. The waste liquid recycling and treatment system for electroless nickel plating bath according to claim 1, characterized in that: The electroless nickel plating solution is stored in a raw water tank for electroless nickel plating solution, and the raw water tank for electroless nickel plating solution is connected to the inlet of the first sedimentation separation tank through a booster pump.

3. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 1, characterized in that: It also includes a liquid alkali tank, which is used to introduce liquid alkali into the first precipitation separation tank, the nickel electrowinning tank and the second precipitation separation tank respectively.

4. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 3, characterized in that: The liquid alkali tank has a main pipeline and three branch pipelines at its outlet. One end of the main pipeline is connected to the outlet of the liquid alkali tank, and a liquid pump is installed on the main pipeline. The other end of the main pipeline is connected to the three branch pipelines respectively, and each branch pipeline is equipped with a valve.

5. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 1, characterized in that: A first plate and frame filter press is installed between the first sedimentation separation tank and the clear liquid collection tank. The first plate and frame filter press is used to perform solid-liquid separation on the water after sedimentation reaction in the first sedimentation separation tank, and the filtrate is discharged to the clear liquid collection tank.

6. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 1, characterized in that: The inlet of the nickel electrodeposition cell is located at the lower part of the nickel electrodeposition cell, and the outlet of the nickel electrodeposition cell is located at the upper side of the nickel electrodeposition cell; the nickel electrodeposition cell is equipped with a heating device and a ventilation fan; an adjustable-flow water pump is installed on the connecting pipeline between the clear liquid collection tank and the nickel electrodeposition cell.

7. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 1, characterized in that: The electrolytic lean solution recovery mechanism uses a nickel recovery resin column, and the outlet of the nickel recovery resin column is connected to the second precipitation separation tank.

8. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 7, characterized in that: The nickel recovery resin column is also connected to a pure water storage tank and a dilute sulfuric acid preparation tank. The outlet of the nickel recovery resin column is also connected to a nickel-rich desorption liquid collection tank, which is connected to the inlet of the nickel electrowinning cell.

9. The waste liquid recycling and treatment system for electroless nickel plating bath according to claim 1, characterized in that: It also includes a lime slurry storage tank, which is connected to a second sedimentation separation tank. A second plate and frame filter press is installed between the second sedimentation separation tank and the electrocatalytic oxidation tank. The second plate and frame filter press is used to perform solid-liquid separation on the water after sedimentation reaction in the second sedimentation separation tank, and the filtrate is sent into the electrocatalytic oxidation tank.

10. The waste liquid recovery and treatment system for electroless nickel plating bath according to claim 1, characterized in that: The outlet of the triple-effect evaporator is also connected to a condensate collection tank and a crystallized salt storage tank.

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