Electroplating wastewater treatment device and process

Abstract

The invention relates to the technical field of wastewater treatment, in particular to an electroplating wastewater treatment device and process, and the electroplating wastewater treatment device sequentially comprises an adsorption tower, a sedimentation tank, an ion exchange tank, a heat exchange tank, a heat exchanger and a falling film evaporator, the sedimentation tank is used for adding a reagent for removing cyanide and chromate, the sedimentation tank is connected with the ion exchange tank, and the ion exchange tank is used for exchanging metal ions in the electroplating wastewater; one end of the heat exchange tank is connected with the ion exchange pool, the other end of the heat exchange tank is connected with the heat exchanger, the heat exchange tank is used for introducing electroplating wastewater into the heat exchanger for heat exchange, the heat exchanger is connected with the falling film evaporator, and the falling film evaporator is used for evaporating and concentrating the electroplating wastewater; and a return pipe is also arranged between the heat exchanger and the heat exchange tank and is used for introducing the electroplating wastewater of which the temperature is not enough to evaporate into the heat exchange tank. The electroplating wastewater is evaporated and concentrated after being subjected to precipitation and ion exchange, so that the treatment effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to an electroplating wastewater treatment device and process. Background Art

[0002] The manufacture of printed circuit boards requires a large amount of electroplating technology, which will produce a lot of electroplating wastewater. The water quality of electroplating wastewater is complex and its composition is difficult to control. It contains heavy metal ions such as chromium, cadmium, and nickel, as well as highly toxic substances such as cyanide. Therefore, the treatment process of electroplating water is relatively complicated. Under the existing technology, precipitation and ion exchange methods are usually used to treat electroplating wastewater. Among them, precipitation method is less stable but has lower cost, while ion exchange method has stable effect but higher cost, and the salt content in the treated wastewater is higher. Electroplating wastewater treated by both methods is prone to poor treatment effect. Summary of the invention

[0003] In order to solve the problem that electroplating wastewater treated by precipitation method and ion exchange method in the prior art is prone to poor treatment effect, the present application provides an electroplating wastewater treatment device, and the specific scheme is as follows.

[0004] An electroplating wastewater treatment device comprises an adsorption tower, a sedimentation tank, an ion exchange tank, a heat exchange tank, a heat exchanger, and a falling film evaporator in sequence, wherein the adsorption tower is used to add activated carbon and electroplating wastewater, the adsorption tower is connected to the sedimentation tank, the sedimentation tank is used to add reagents for removing cyanide and chromide, the sedimentation tank is connected to the ion exchange tank, and the ion exchange tank is used to exchange metal ions in the electroplating wastewater; One end of the heat exchange tank is connected to the ion exchange tank, and the other end of the heat exchange tank is connected to the heat exchanger. The heat exchange tank is used to pass the electroplating wastewater into the heat exchanger for heat exchange. The heat exchanger is connected to the falling film evaporator, and the falling film evaporator is used to evaporate and concentrate the electroplating wastewater. A reflux pipe is also provided between the heat exchanger and the heat exchange tank, and the reflux pipe is used to pass electroplating wastewater whose temperature is not high enough for evaporation into the heat exchange tank.

[0005] By adopting the above technical scheme, the electroplating wastewater is not only precipitated by activated carbon, but also undergoes certain ion exchange in the ion exchange tank. Both methods are carried out, which can complement the shortcomings of the other method and reduce the shortcomings of the two methods. In addition, in the subsequent treatment process, the electroplating wastewater is evaporated and concentrated to further separate the waste materials, further improving the treatment effect of the wastewater. Optionally, a heat exchange tube and a discharge pipe are further provided in the heat exchanger, one end of the heat exchange tube is connected to the heat exchange tank, and the other end of the heat exchange tube is provided with a partition, and the partition divides the heat exchange tube into two independent spaces that are not connected to each other, the heat exchange tube on one side of the partition is connected to the discharge pipe, and the end of the discharge pipe away from the heat exchange tube is connected to the falling film evaporator, the heat exchange tube on one side of the partition is connected to the return pipe, and the end of the return pipe away from the heat exchange tube is connected to the heat exchange tank, and a thermistor is provided on the side where the heat exchange tube is connected to the return pipe, and the thermistor expands when heated.

[0006] By adopting the above technical scheme, a heat exchange tube and a discharge tube are arranged, and the liquid in the heat exchange tube can absorb the heat energy at the heat exchanger to increase the temperature. The electroplating wastewater reaching the evaporation temperature is discharged into the falling film evaporator through the discharge tube, and the electroplating wastewater is diverted to the reflux tube and the discharge tube through the partition to reduce the overall flow rate of the electroplating wastewater. When the overall electroplating wastewater temperature is high and can reach the evaporation temperature, the diversion at the reflux tube is closed to reduce the volume of the flow channel, thereby increasing the flow rate of the electroplating wastewater meeting the evaporation temperature entering the discharge tube, so that the electroplating wastewater can be passed into the falling film evaporator for evaporation and concentration, reducing the situation where the temperature is too low to evaporate. When the electroplating wastewater cannot close the reflux tube temperature, the reflux tube is opened to pass part of the heated wastewater back to the heat exchange tank to increase the temperature in the heat exchange tank, so that the wastewater in the heat exchange tank can reach a higher temperature during heat exchange, and a small part of the electroplating wastewater that enters the falling film evaporator through the discharge tube can reach the evaporation temperature after the electroplating wastewater after reflux circulation and heating is passed into the mixing.

[0007] Optionally, the thermosensitive block is fixedly connected to the partition, and a rubber pad is fixedly provided on the thermosensitive block, and the rubber pad is used to abut against the inner wall of the heat exchange tube.

[0008] By adopting the above technical solution, a rubber pad is arranged on the thermistor, and the rubber pad can be pressed tightly against the inner wall of the thermistor, thereby reducing the leakage of water from the gap.

[0009] Optionally, the heat exchange tube on the upper side of the partition is connected to the discharge pipe, and the heat exchange tube on the lower side of the partition is connected to the return pipe.

[0010] By adopting the above technical solution, since the density of hot water is less than that of cold water, when electroplating wastewater with temperature difference flows at the same time, the high-temperature hot water is more likely to be in the upper layer of cold water. At this time, the wastewater with higher temperature on the upper side can pass into the falling film evaporator through the discharge pipe, and the wastewater with lower temperature on the lower side can re-enter the heat exchange tank through the reflux pipe for re-heat exchange.

[0011] Optionally, a thermosensitive strip is fixedly disposed in the heat exchange tube, and the thermosensitive strip is disposed along the length direction of the heat exchange tube. When the thermosensitive strip expands, it will not abut against the inner wall of the thermosensitive tube.

[0012] By adopting the above technical solution, a thermosensitive strip is arranged in the heat exchange tank. After the thermosensitive strip expands due to heat, the volume in the heat exchange tube can be further reduced. At this time, the thermosensitive block closes the passage of the reflux pipe. Since the volume at the discharge pipe remains unchanged and the water flow rate per second remains unchanged, the flow rate at the discharge pipe can be further increased. Therefore, when the temperature meets the evaporation conditions, the electroplating wastewater can enter the falling film evaporator through the discharge pipe with faster efficiency.

[0013] Optionally, the thermosensitive strip is arranged on the lower side of the partition, and the thermosensitive strip is arranged along the inner wall of the heat exchange tube and fixedly connected to the inner wall of the heat exchange tube.

[0014] By adopting the above technical solution, the thermosensitive strip is arranged on the lower side of the partition. When the thermosensitive strip expands, it can guide the electroplating wastewater, guiding the electroplating wastewater to a position close to the discharge pipe, further increasing the speed at which the electroplating wastewater that meets the evaporation temperature enters the discharge pipe.

[0015] Optionally, the thermosensitive strip is arranged at a position close to the heat exchange tube and close to the partition, and the thermosensitive strip can abut against the partition when it expands due to heat.

[0016] By adopting the above technical solution, the thermistor strip is set near the partition. The thermistor strip can assist the thermistor block in shielding the reflux pipe. When the heat of the electroplating wastewater meets the evaporation conditions, the situation of the electroplating wastewater entering the reflux pipe is further reduced.

[0017] Optionally, the partition is arranged along the length direction of the heat exchange tube and along the axis of the heat exchange tube, the spatial cross-sectional areas on the upper and lower sides of the partition are the same, and the partition is fixedly connected to the inner wall of the heat exchange tube.

[0018] By adopting the above technical solution, the partition is arranged along the length direction of the heat exchange tube and along the axis of the heat exchange tank, and the cross-sectional areas on the upper and lower sides of the partition are the same, thereby reducing the different flow rates of electroplating wastewater entering the discharge pipe and the reflux pipe.

[0019] The present application also provides an electroplating wastewater treatment process, comprising the electroplating wastewater treatment device described above, using the following method: a. Send the electroplating wastewater into the adsorption tower for adsorption by activated carbon; b. Passing the adsorbed electroplating wastewater into a sedimentation tank for further precipitation and treatment of cyanide and chromide; c. Pass the electroplating wastewater into the ion exchange tank for ion exchange; d. Pass the electroplating wastewater into the heat exchange tank and pump the electroplating wastewater into the heat exchanger for heat exchange; e. The electroplating wastewater with sufficient temperature for evaporation is passed into the falling film evaporator, and the electroplating wastewater with insufficient temperature is returned to the heat exchange tank.

[0020] By adopting the above technical scheme, the electroplating wastewater can be treated by the precipitation method and the ion exchange method successively. The advantages and disadvantages of the precipitation method and the ion exchange method complement each other to improve the treatment effect. Subsequently, the treated wastewater is passed into a falling film evaporator for evaporation and concentration to further separate the waste from the wastewater, thereby reducing the situation of poor treatment effect during wastewater treatment.

[0021] In summary, this application has at least the following beneficial effects: 1. The present application solves the problem that electroplating wastewater treated by precipitation method and ion exchange method under the prior art is prone to difficult cost control and poor treatment effect. The present application treats the electroplating wastewater by two methods in succession. The two treatment methods complement each other and can reduce the situation where the treatment effect is poor when only one method is used for treatment. At the same time, an evaporation concentration treatment method is added after the two methods to further improve the treatment effect of the wastewater.

[0022] 2. The present application also provides a heat exchanger that can determine whether the electroplating wastewater meets the evaporation temperature, and refluxes the electroplating wastewater that does not meet the evaporation temperature, thereby reducing the situation where the temperature of the electroplating wastewater cannot meet the evaporation temperature during the evaporation and concentration process, and further improving the treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a stereogram of this embodiment.

[0024] Figure 2 is a cross-sectional view of this embodiment.

[0025] Description of reference numerals: 1. Adsorption tower; 2. Sedimentation tank; 3. Ion exchange cell; 4. Heat exchange tank; 5. Heat exchanger; 51. Reflux pipe; 52. Heat exchange pipe; 521. Baffle; 522. Thermistor block; 523. Rubber pad; 524. Thermistor strip; 53. Discharge pipe; 6. Falling film evaporator; 7. Water pump. DETAILED DESCRIPTION

[0026] The present application is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0027] An electroplating wastewater treatment device, such as Figure 1As shown, it includes an adsorption tower 1, a sedimentation tank 2, an ion exchange tank 3, a heat exchange tank 4, a heat exchanger 5, and a falling film evaporator 6 in sequence. The adsorption tower 1 is used to add activated carbon and electroplating wastewater. The adsorption tower 1 is connected to the sedimentation tank 2. The sedimentation tank 2 is used to add reagents for removing cyanide and chromide. The sedimentation tank 2 is connected to the ion exchange tank 3. The ion exchange tank 3 is used to exchange metal ions in the electroplating wastewater. In specific implementation, a water pump 7 is set at each connection to extract the wastewater. The electroplating wastewater can reduce COD in the adsorption tower 1 and remove it. In the sedimentation tank 2, a decyanation agent such as hydrogen peroxide can be added to remove cyanide. The chromide is directly added by adding a dechroming agent. Then, the ion exchange tank 3 uses a commonly used ion exchange method to perform a replacement reaction on various ions, thereby completing the removal of various ions, thereby completing the preliminary treatment.

[0028] like Figure 1 As shown, one end of the heat exchange tank 4 is connected to the ion exchange cell 3, and the other end of the heat exchange tank 4 is connected to the heat exchanger 5. The heat exchange tank 4 is used to pass the electroplating wastewater into the heat exchanger 5 for heat exchange. The heat exchanger 5 is connected to the falling film evaporator 6. The falling film evaporator 6 is used to evaporate and concentrate the electroplating wastewater. A reflux pipe 51 is also provided between the heat exchanger 5 and the heat exchange tank 4. The reflux pipe 51 is used to pass the electroplating wastewater whose temperature is not enough for evaporation into the heat exchange tank 4. In specific implementation, the electroplating wastewater that has completed the first few steps can be sent to the falling film evaporator 6 for subsequent further treatment, but before being sent to the falling film evaporator 6, the electroplating wastewater needs to reach a temperature that meets the evaporation temperature before it can be evaporated and concentrated normally in the falling film evaporator 6. In other embodiments, multiple heat exchangers 5 can be arranged in the heat exchange tank 4 and the falling film evaporator 6 to further improve the effect of increasing the temperature of the electroplating wastewater, so that the electroplating wastewater can meet the evaporation temperature before entering the falling film evaporator 6. A crystallization separation device can also be arranged after the falling film evaporator 6 to further treat the wastewater and further increase the treatment effect of the wastewater.

[0029] like Figure 1 and Figure 2As shown, the heat exchanger 5 is also provided with a heat exchange tube 52 and a discharge tube 53. One end of the heat exchange tube 52 is connected to the heat exchange tank 4, and the other end of the heat exchange tube 52 is provided with a partition 521. The partition 521 divides the heat exchange tube 52 into two independent spaces that are not connected to each other. The heat exchange tube 52 on one side of the partition 521 is connected to the discharge tube 53, and the end of the discharge tube 53 away from the heat exchange tube 52 is connected to the falling film evaporator 6. The heat exchange tube 52 on one side of the partition 521 is connected to the return tube 51, and the end of the return tube 51 away from the heat exchange tube 52 is connected to the heat exchange tank 4. A thermistor block 522 is provided at the side where the heat exchange tube 52 is connected to the return tube 51, and the thermistor block 522 blocks the passage when it expands due to heat. In a specific implementation, the heat exchanger 5 can heat the electroplating wastewater in the heat exchange tube 52. Since the partition 521 divides the heat exchange tube 52 into two parts, when the electroplating wastewater in the heat exchange tube 52 rises to meet the evaporation temperature, the thermistor block 522 blocks the branch at the return pipe 51. At this time, the flow rate to the discharge pipe 53 increases. Since the volume at the position of the discharge pipe 53 remains unchanged, the flow rate at this time can be increased, so that the electroplating wastewater that meets the evaporation temperature can be accelerated. When the temperature of the electroplating wastewater is low, the thermistor 522 shrinks and opens the passage, and the electroplating wastewater with insufficient temperature is re-entered into the heat exchange tank 4 to heat the wastewater in the heat exchange tank 4. At this time, the flow rate at the discharge pipe 53 is reduced, and the flow rate entering the falling film evaporator 6 is also reduced. When the wastewater meeting the evaporation condition temperature is subsequently introduced, it can be re-introduced into the falling film evaporator 6 at a faster speed and mixed with the previously introduced wastewater, so that the wastewater in the falling film evaporator 6 reaches the evaporation condition.

[0030] like Figure 1 and Figure 2 As shown, the thermosensitive block 522 is fixedly connected to the partition 521, and a rubber pad 523 is fixedly arranged on the thermosensitive block 522, and the rubber pad 523 is used to abut against the inner wall of the heat exchange tube 52. In specific implementation, the rubber pad 523 can fit closely with the inner wall of the heat exchange tube 52, reducing the outflow of electroplating wastewater from the gap and reducing the flow rate of wastewater that meets the evaporation temperature.

[0031] like Figure 2 As shown, the heat exchange tube 52 on the upper side of the partition 521 is connected to the discharge pipe 53, and the heat exchange tube 52 on the lower side of the partition 521 is connected to the return pipe 51. In specific implementation, since the density of hot water is lower than the temperature of cold water, the hot water is usually on the upper side of the cold water, so when the temperature is insufficient and the waste water is diverted, it can be ensured that the waste water with higher temperature enters the discharge pipe 53.

[0032] like Figure 2As shown, a thermosensitive strip 524 is fixedly arranged in the heat exchange tube 52. The thermosensitive strip 524 is arranged along the length direction of the heat exchange tube 52. When the thermosensitive strip 524 expands, it will not abut the inner wall of the thermosensitive tube. The thermosensitive strip 524 is arranged on the lower side of the partition 521. The thermosensitive strip 524 is arranged along the inner wall of the heat exchange tube 52 and is fixedly connected to the inner wall of the heat exchange tube 52. The thermosensitive strip 524 is arranged at a position close to the heat exchange tube 52 and close to the partition 521. When the thermosensitive strip 524 expands due to heat, it can abut against the partition 521, and assist the thermosensitive block 522 in shielding the return pipe 51. In specific implementation, when the thermosensitive strip 524 expands due to heat, the thermosensitive strip 524 will squeeze upward to reduce the volume in the heat exchange tube 52. Since the water intake is unchanged, the wastewater flow rate in the heat exchange tube 52 will increase at this time, thereby further increasing the speed at which the wastewater that meets the evaporation temperature enters the discharge pipe 53.

[0033] like Figure 2 As shown, the partition 521 is arranged along the length direction of the heat exchange tube 52 and along the axis of the heat exchange tube 52. The spatial cross-sectional areas on the upper and lower sides of the partition 521 are the same. The partition 521 is fixedly connected to the inner wall of the heat exchange tube 52 by seamless welding.

[0034] The present application also provides an electroplating wastewater treatment process, comprising the electroplating wastewater treatment device described above, using the following method: a. Send the electroplating wastewater into the adsorption tower 1 for adsorption by activated carbon; b. Passing the adsorbed electroplating wastewater into sedimentation tank 2 to further precipitate and treat cyanide and chromide; c. passing the electroplating wastewater into the ion exchange tank 3 for ion exchange; d. Pass the electroplating wastewater into the heat exchange tank 4 and pump the electroplating wastewater into the heat exchanger 5 for heat exchange; e. The electroplating wastewater with sufficient temperature for evaporation is passed into the falling film evaporator 6, and the electroplating wastewater with insufficient temperature is returned to the heat exchange tank 4.

[0035] Working principle: The electroplating wastewater passes through various components in sequence, and is treated by sedimentation and ion exchange methods in succession. The electroplating wastewater is then sent to the falling film evaporator 6 to evaporate and concentrate the electroplating wastewater, thereby completing the wastewater treatment.

[0036] The above are preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An electroplating wastewater treatment device, characterized in that: The invention comprises an adsorption tower (1), a sedimentation tank (2), an ion exchange tank (3), a heat exchange tank (4), a heat exchanger (5), and a falling film evaporator (6), wherein the adsorption tower (1) is used to add activated carbon and electroplating wastewater, the adsorption tower (1) is connected to the sedimentation tank (2), the sedimentation tank (2) is used to add reagents for removing cyanide and chromium compounds, the sedimentation tank (2) is connected to the ion exchange tank (3), and the ion exchange tank (3) is used to exchange metal ions in the electroplating wastewater; One end of the heat exchange tank (4) is connected to the ion exchange tank (3), and the other end of the heat exchange tank (4) is connected to the heat exchanger (5). The heat exchange tank (4) is used to pass the electroplating wastewater into the heat exchanger (5) for heat exchange. The heat exchanger (5) is connected to the falling film evaporator (6). The falling film evaporator (6) is used to evaporate and concentrate the electroplating wastewater. A reflux pipe (51) is also provided between the heat exchanger (5) and the heat exchange tank (4), and the reflux pipe (51) is used to pass electroplating wastewater whose temperature is not high enough for evaporation into the heat exchange tank (4).

2. The electroplating wastewater treatment device according to claim 1, characterized in that: The heat exchanger (5) is further provided with a heat exchange tube (52) and a discharge tube (53). One end of the heat exchange tube (52) is connected to the heat exchange tank (4), and the other end of the heat exchange tube (52) is provided with a partition (521). The partition (521) divides the heat exchange tube (52) into two upper and lower independent spaces that are not connected to each other. The heat exchange tube (52) on one side of the partition (521) is connected to the discharge tube (53). The end of the heat exchange tube (53) away from the heat exchange tube (52) is connected to the falling film evaporator (6), the heat exchange tube (52) on one side of the partition (521) is connected to the return tube (51), the end of the return tube (51) away from the heat exchange tube (52) is connected to the heat exchange tank (4), and a thermistor block (522) is provided on the side where the heat exchange tube (52) is connected to the return tube (51), and the thermistor block (522) blocks the passage when it expands due to heat.

3. The electroplating wastewater treatment device according to claim 2, characterized in that: The thermosensitive block (522) is fixedly connected to the partition (521), and a rubber pad (523) is fixedly arranged on the thermosensitive block (522), and the rubber pad (523) is used to abut against the inner wall of the heat exchange tube (52).

4. The electroplating wastewater treatment device according to claim 2, characterized in that: The heat exchange tube (52) on the upper side of the partition (521) is connected to the discharge tube (53), and the heat exchange tube (52) on the lower side of the partition (521) is connected to the return tube (51).

5. The electroplating wastewater treatment device according to claim 4, characterized in that: A thermosensitive strip (524) is also fixedly arranged inside the heat exchange tube (52). The thermosensitive strip (524) is arranged along the length direction of the heat exchange tube (52). When the thermosensitive strip (524) expands, it will not abut against the inner wall of the thermosensitive tube.

6. The electroplating wastewater treatment device according to claim 5, characterized in that: The thermosensitive strip (524) is arranged on the lower side of the partition (521); the thermosensitive strip (524) is arranged along the inner wall of the heat exchange tube (52) and is fixedly connected to the inner wall of the heat exchange tube (52).

7. The electroplating wastewater treatment device according to claim 6, characterized in that: The thermosensitive strip (524) is arranged at a position close to the heat exchange tube (52) and close to the partition (521); the thermosensitive strip (524) can abut against the partition (521) when it expands due to heat.

8. The electroplating wastewater treatment device according to claim 2, characterized in that: The partition (521) is arranged along the length direction of the heat exchange tube (52) and along the axis of the heat exchange tube (52); the spatial cross-sectional areas on the upper and lower sides of the partition (521) are the same; and the partition (521) is fixedly connected to the inner wall of the heat exchange tube (52).

9. A process for treating electroplating wastewater, comprising the electroplating wastewater treatment device according to any one of claims 1 to 9, using the following method: a. sending the electroplating wastewater into an adsorption tower (1) for adsorption by activated carbon; b. passing the adsorbed electroplating wastewater into a sedimentation tank (2) to further precipitate and treat cyanide and chromium compounds; c. passing the electroplating wastewater into an ion exchange tank (3) for ion exchange; d. passing the electroplating wastewater into the heat exchange tank (4) and pumping the electroplating wastewater into the heat exchanger (5) for heat exchange; e. The electroplating wastewater with a temperature sufficient for evaporation is passed into the falling film evaporator (6), while the electroplating wastewater with an insufficient temperature is returned to the heat exchange tank (4).

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