Aluminum foil wastewater treatment system and process

Abstract

The application discloses an aluminum foil wastewater treatment system and process, and belongs to the field of wastewater treatment. The aluminum foil wastewater treatment system comprises a wastewater collecting tank, a pretreatment device, an ultrafiltration system, a nanofiltration system, a recovery tank and an electrolytic tank. The effluent outlet of the wastewater collecting tank is communicated with the pretreatment device. The supernatant outlet of the pretreatment device is communicated with the ultrafiltration system. The water outlet of the ultrafiltration system is communicated with the nanofiltration system. The water outlet of the nanofiltration system is communicated with the recovery tank. The concentrated water outlet of the nanofiltration system is communicated with the electrolytic tank. The aluminum foil wastewater treatment system and process can realize resourceful treatment of aluminum foil wastewater, recover hydrochloric acid and aluminum metal, and the effluent quality can meet environmental protection requirements.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and particularly relates to an aluminum foil wastewater treatment system and process. Background Technology

[0002] Aluminum foil, due to its excellent barrier properties, thermal conductivity, flexibility, and recyclability, is widely used in many fields such as food packaging, electronics, pharmaceuticals, and construction. With the continuous growth in demand for aluminum foil from various industries, the scale of aluminum foil production is expanding daily. However, the aluminum foil production process generates a large amount of wastewater. If not effectively treated and recycled, it will not only cause serious environmental pollution but also lead to a significant waste of resources.

[0003] Aluminum foil wastewater has a complex composition, with major pollutants including hydrochloric acid, metallic aluminum (existing in the form of aluminum ions), suspended solids, grease, and other organic impurities. The presence of these pollutants makes aluminum foil wastewater highly acidic and has a high chemical oxygen demand (COD). Direct discharge of such wastewater would cause serious harm to aquatic ecosystems, soil, and groundwater.

[0004] Traditional methods for treating aluminum foil wastewater primarily employ neutralization precipitation and coagulation precipitation processes to remove aluminum ions from the wastewater as aluminum hydroxide precipitate, followed by neutralization to meet discharge standards. While this approach reduces the concentration of aluminum ions and acidity in the wastewater, it has several drawbacks. Firstly, the large amount of aluminum hydroxide precipitate requires further treatment, increasing costs and environmental burden. Secondly, the hydrochloric acid and metallic aluminum resources in the wastewater are not effectively recovered, resulting in resource waste. Furthermore, traditional methods often fail to completely remove organic impurities from the wastewater, making it difficult for the effluent to meet increasingly stringent environmental protection requirements. Summary of the Invention

[0005] The purpose of this invention is to provide an aluminum foil wastewater treatment system and process to overcome at least one of the above-mentioned defects in the prior art.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] The present invention provides an aluminum foil wastewater treatment system, comprising a wastewater collection tank, a pretreatment device, an ultrafiltration system, a nanofiltration system, a recovery tank, and an electrolytic cell. The outlet of the wastewater collection tank is connected to the pretreatment device, the supernatant outlet of the pretreatment device is connected to the ultrafiltration system, the permeate outlet of the ultrafiltration system is connected to the nanofiltration system, the permeate outlet of the nanofiltration system is connected to the recovery tank, and the concentrate outlet of the nanofiltration system is connected to the electrolytic cell.

[0008] Preferably, the pretreatment equipment includes a box, a stirring assembly, a transmission assembly, a lifting component, and a lifting frame. The stirring assembly and the lifting component are fixed on the top of the box. The stirring end of the stirring assembly is located inside the box. The lifting component is connected to the stirring assembly through the transmission assembly. The lifting end of the lifting component is fixed with a lifting frame, which is located inside the box.

[0009] Preferably, the stirring assembly includes a first bearing seat, a stirring shaft, and stirring blades. The first bearing seat is fixed to the top of the housing, and the lower part of the stirring shaft passes through the first bearing seat and the top wall of the housing, and extends into the interior of the housing where two layers of stirring blades are fixedly arranged at intervals.

[0010] Preferably, the lifting component includes a motor, a first rotating shaft, a first bevel gear, a second bevel gear, a second bearing seat, a second rotating shaft, a cam, a connecting frame, a guide sleeve, and a guide rod. The top of the housing is fixed with the motor and the second bearing seat. The top of the motor is fixed with the first rotating shaft. The top of the first rotating shaft is fixed with the first bevel gear. The left end of the second rotating shaft is fixed with the second bevel gear, which meshes with the first bevel gear. The right end of the second rotating shaft is fixed with the cam. Guide sleeves are fixed on both the left and right sides of the top of the housing. The bottom end of the guide rod passes through the guide sleeve and the top wall of the housing and extends into the interior of the housing where the lifting frame is fixed. The left and right guide rods are connected by a connecting frame, and the cam contacts the bottom wall of the connecting frame.

[0011] Preferably, the transmission assembly includes a driving wheel, a driven wheel, and a transmission belt. The driving wheel is fixed to the first rotating shaft, the driven wheel is fixed to the stirring shaft, and the driving wheel and the driven wheel are connected by the transmission belt.

[0012] Preferably, the lifting frame includes a ring, a first horizontal plate, a second horizontal plate, and a vertical plate. The first horizontal plate is fixed to both the left and right side walls of the ring. The vertical plate is fixed to the outer end of the first horizontal plate. The second horizontal plate is fixed to the inner side of the lower part of the vertical plate. The stirring blades in the upper layer are located between the first and second horizontal plates. The second horizontal plate is located between the upper and lower stirring blades. The stirring shaft passes through the ring. The bottom end of the guide rod is connected to the top end of the vertical plate.

[0013] Preferably, it also includes a medicine storage tank, a third bearing, a vertical pipe, a sealing ring, and a first valve. The medicine storage tank is fixed to the top of the housing, and the bottom of the medicine storage tank is fixedly connected to the vertical pipe. The vertical pipe is equipped with the first valve. The stirring shaft has a first cavity inside, and the third bearing is fixed above the inside of the first cavity. The bottom end of the vertical pipe passes through the third bearing. A sealing ring is provided between the vertical pipe and the side wall of the stirring shaft. The stirring blade has a second cavity inside that communicates with the first cavity. The front and rear side walls of the stirring blade both have first through holes that communicate with the second cavity.

[0014] Preferably, it also includes an air pump, a connecting pipe, and a second valve. An air pump is fixed to the top of the housing. The right side of the air pump's outlet pipe is fixedly connected to a connecting pipe. The right end of the connecting pipe is fixedly connected to a vertical pipe, and the connection point is located below the first valve. The connecting pipe is equipped with a second valve.

[0015] Preferably, it also includes a hose and a third valve. The side wall of the ring has a third cavity. The interior of the first horizontal plate, the second horizontal plate, and the vertical plate all have a fourth cavity. The fourth cavity of the first horizontal plate is connected to the third cavity and the fourth cavity of the vertical plate. The fourth cavity of the vertical plate is connected to the fourth cavities of the vertical plate and the second vertical plate. The front and rear side walls of the first horizontal plate, the second horizontal plate, and the vertical plate all have second through holes that communicate with their respective fourth cavities. One end of the hose is fixedly connected to the left side of the air outlet pipe of the air pump, and the other end of the hose is connected to the fourth cavity of the first horizontal plate. The hose is equipped with a third valve.

[0016] This invention also provides an aluminum foil wastewater treatment process, which uses the above-mentioned aluminum foil wastewater treatment system and includes the following steps: sending aluminum foil wastewater into a wastewater collection tank, homogenizing and equalizing the wastewater in the collection tank, and then sending it into a pretreatment device for pretreatment. The supernatant after pretreatment is sent into an ultrafiltration system for ultrafiltration treatment. The permeate obtained from ultrafiltration is sent into a nanofiltration system for nanofiltration treatment. The permeate obtained from nanofiltration is sent into a recovery tank to recover hydrochloric acid. The concentrated water obtained from nanofiltration is sent into an electrolytic cell for electrolysis treatment to obtain metallic aluminum.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. To achieve resource-based treatment of aluminum foil wastewater, recover hydrochloric acid and metallic aluminum, and ensure that the effluent quality meets environmental protection requirements.

[0019] 2. By combining the stirring assembly with the lifting components and lifting frame, not only is thorough mixing achieved through the stirring assembly, but the vertically adjustable lifting frame also disturbs the liquid, breaking down the vertical stratification of the water. This allows the mixture at different heights to fully blend, ensuring uniform distribution of the coagulant throughout the entire water body, improving coagulation efficiency, and creating a complex flow field. This complex flow field diversifies the liquid's flow path, increasing the collision opportunities between fluid micro-clusters. The interweaving of water flows at different directions and speeds allows the coagulant to come into contact with pollutant particles in the wastewater more frequently, thereby promoting coagulation and flocculation reactions and helping to form larger and denser flocs.

[0020] 3. During the floc formation process, the up-and-down movement of the lifting frame changes the speed and direction of the water flow, causing the floc particles to move in different water flow environments. It brings together particles that were originally in different positions, increases the probability of collision between particles, and promotes the growth and aggregation of flocs.

[0021] 4. The rotation of the stirring blades, combined with the lifting of the lifting frame, applies a certain shearing force to the flocs, making the particles inside the flocs more compact and orderly. This well-structured flocs have better settling performance, which is beneficial to the subsequent solid-liquid separation process and reduces sedimentation time and floor space.

[0022] 5. The water flow fluctuations generated during the movement of the lifting frame can also flush the walls of the tank, which can reduce the adhesion and accumulation of flocs and impurities on the walls, keep the tank walls clean, prevent scaling from adversely affecting the coagulation effect, and maintain good water flow inside the tank.

[0023] 6. Only one drive source (motor) is needed to realize the up-and-down reciprocating motion of the lifting frame and the continuous stirring operation of the stirring blade. The two actions are linked to achieve the stirring operation while disturbing the liquid, effectively ensuring the full coagulation and sedimentation process.

[0024] 7. The movement of the first and second horizontal plates generates additional disturbances to the liquid around the stirring blades, making the vortex formed by the stirring blades more complex.

[0025] 8. Adding the coagulant directly from the mixing end while stirring ensures that the coagulant can be quickly and evenly dispersed in the wastewater within the tank.

[0026] 9. During the mixing process, the jetting air breaks the laminar flow of the liquid, allowing the coagulant and other components to disperse more quickly and evenly in the mixture.

[0027] 10. The complex and varied movement trajectory of the bubbles interacts with the water flow generated by the stirring blades and the lifting frame, further increasing the flow complexity of the mixture. This complex flow field allows the liquid in different areas to mix more thoroughly, reducing the concentration gradient and velocity gradient that may exist in the mixture, and enabling the coagulation reaction to proceed under more uniform conditions.

[0028] 11. The bubbles generated by the injected airflow can act as coagulation nuclei, attracting colloidal particles and fine suspended solids in the wastewater. These particles aggregate on the bubble surface, gradually forming tiny flocs. As the bubbles rise and the stirring blades agitate, more particles are adsorbed onto the flocs, promoting floc growth.

[0029] 12. As the bubbles rise, they exert a certain buoyancy and impact force on the flocs, causing the flocs to be continuously subjected to external forces during their formation. These external forces help the particles inside the flocs to bind more tightly, thus enhancing the structural strength of the flocs.

[0030] 13. The injected gas forms sufficient dissolved oxygen, which helps to promote some oxidation reactions in the water. Some pollutants are more easily removed by coagulants under aerobic conditions. For example, some reducing substances can be oxidized into forms that are easier to precipitate under the action of dissolved oxygen. In addition, dissolved oxygen can also inhibit the growth of some harmful microorganisms and prevent them from having a negative impact on the coagulation process.

[0031] 14. Each valve can be opened and closed according to actual usage needs, adapting to different operational requirements and offering high flexibility.

[0032] 15. Gas is ejected from the first and second through holes, which will have a certain scouring effect on the surface of the stirring blade and the lifting frame. This can prevent flocs and impurities from adhering to and accumulating on the surface of the stirring blade and the lifting frame, keep them clean, and ensure normal operation. Attached Figure Description

[0033] Figure 1 This is a system block diagram of the present invention.

[0034] Figure 2 This is a schematic diagram of the first state structure of the pretreatment device of the present invention.

[0035] Figure 3 This is a partial front view structural schematic diagram of the stirring assembly of the present invention.

[0036] Figure 4 This is a schematic diagram of the cooperative structure of the lifting component, transmission component, and stirring component of the present invention.

[0037] Figure 5 This is a right-side structural schematic diagram of the second rotating shaft and cam of the present invention.

[0038] Figure 6 This is a cross-sectional structural diagram of the lifting frame of the present invention.

[0039] Figure 7 This is a schematic diagram of the assembly structure of the third bearing, vertical tube, sealing ring, and stirring shaft of the present invention.

[0040] Figure 8 This is a partial front view structural schematic diagram of the present invention.

[0041] Figure 9 This is a partial cross-sectional view of the stirring assembly of the present invention.

[0042] Figure 10 This is a schematic diagram of the second state structure of the pretreatment device of the present invention.

[0043] The labels in the attached diagram are as follows: 100-Wastewater collection tank, 200-Pretreatment equipment, 300-Ultrafiltration system, 400-Nanofiltration system, 500-Recovery tank, 600-Electrolytic cell, 1-Box body, 2-Agitator assembly, 3-Transmission assembly, 4-Lifting component, 5-Lifting frame, 21-First bearing seat, 22-Agitator shaft, 23-Agitator blade, 41-Motor, 42-First rotating shaft, 43-First bevel gear, 44-Second bevel gear, 45-Second bearing seat, 46-Second rotating shaft, 47-Cam, 48-Connecting frame, 49 - Guide sleeve, 410 - Guide rod, 31 - Driving wheel, 32 - Driven wheel, 33 - Transmission belt, 51 - Ring sleeve, 52 - First horizontal plate, 53 - Second horizontal plate, 54 - Vertical plate, 6 - Medicine storage box, 7 - Third bearing, 8 - Vertical pipe, 9 - Sealing ring, 10 - First valve, 221 - First cavity, 231 - Second cavity, 232 - First through hole, 11 - Air pump, 12 - Connecting pipe, 13 - Second valve, 14 - Hose, 15 - Third valve, 511 - Third cavity, 55 - Fourth cavity, 56 - Second through hole. Detailed Implementation

[0044] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0045] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not 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 the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] like Figures 1 to 10 As shown, the aluminum foil wastewater treatment system provided in this embodiment includes a wastewater collection tank 100, a pretreatment device 200, an ultrafiltration system 300, a nanofiltration system 400, a recovery tank 500, and an electrolytic cell 600. The outlet of the wastewater collection tank 100 is connected to the pretreatment device 200, the supernatant outlet of the pretreatment device 200 is connected to the ultrafiltration system 300, the product water outlet of the ultrafiltration system 300 is connected to the nanofiltration system 400, the product water outlet of the nanofiltration system 400 is connected to the recovery tank 500, and the concentrate outlet of the nanofiltration system 400 is connected to the electrolytic cell 600.

[0047] This embodiment also provides an aluminum foil wastewater treatment process, which uses the above-mentioned aluminum foil wastewater treatment system for treatment, including the following steps:

[0048] Aluminum foil wastewater (mainly containing 1% HCl and 6% aluminum chloride) is sent to wastewater collection tank 100. After homogenization and equalization in wastewater collection tank 100 for a period of time, it is sent to pretreatment equipment 200. Coagulant is added for pretreatment, causing colloids, fine suspended solids and other impurities in the wastewater to coagulate into larger particles and be removed. The supernatant after pretreatment is sent to ultrafiltration system 300 for ultrafiltration treatment. Because pretreatment is carried out before ultrafiltration, most of the colloids, fine suspended solids and other impurities are removed, reducing the amount of impurities entering ultrafiltration system 300, thereby reducing the risk of ultrafiltration membrane fouling, extending the service life of ultrafiltration membrane, and reducing the frequency of membrane cleaning and replacement. After pretreatment, most of the suspended and some dissolved pollutants in the wastewater are removed before entering ultrafiltration system 300 for further filtration. Ultrafiltration system 300 can effectively intercept the remaining suspended solids, colloids, large molecular organic matter, etc., thereby ensuring the water quality of ultrafiltration permeate. The permeate from ultrafiltration is fed into nanofiltration system 400 for further treatment. Driven by pressure differential, divalent and polyvalent ions in the wastewater are retained, resulting in hydrochloric acid being the primary permeate through the nanofiltration membrane. This achieves the separation and purification of hydrochloric acid. The permeate from nanofiltration is then sent to recovery tank 500 to recover hydrochloric acid for reuse in the workshop. Since divalent and polyvalent ions are retained on the concentrate side of nanofiltration system 400, the concentrate is primarily a concentrated aluminum chloride solution. Nanofiltration system 400 removes small-molecule organic matter from the wastewater, working in conjunction with ultrafiltration system 300 to thoroughly remove organic impurities. The concentrate from nanofiltration is then sent to electrolytic cell 600 for electrolytic treatment. A reduction reaction occurs at the cathode, where aluminum ions gain electrons to generate metallic aluminum. The high-purity metallic aluminum collected at the cathode is then collected. This process achieves resource recovery of aluminum foil wastewater, recovering hydrochloric acid and metallic aluminum, while ensuring the effluent quality meets environmental protection requirements.

[0049] The pretreatment equipment 200 includes a box 1, a stirring assembly 2, a transmission assembly 3, a lifting component 4, and a lifting frame 5. The stirring assembly 2 and the lifting component 4 are fixed on the top of the box 1. The stirring end of the stirring assembly 2 is located inside the box 1. The lifting component 4 is connected to the stirring assembly 2 through the transmission assembly 3. The lifting end of the lifting component 4 is fixed with the lifting frame 5, which is located inside the box 1.

[0050] To ensure improved treatment efficiency of the ultrafiltration system 300, it is crucial to ensure a thorough coagulation and sedimentation process, allowing as many large particles as possible to settle. Incomplete sedimentation results in excessive large particles entering the ultrafiltration system 300, accumulating on the membrane surface. While not as severely clogging as fine particles, this can still affect the operational stability of the ultrafiltration system 300. Therefore, this invention utilizes a combination of a stirring assembly 2, a lifting element 4, and a lifting frame 5. This not only ensures thorough mixing through the stirring assembly 2 but also, simultaneously, agitates the liquid vertically through the lifting frame 5. This breaks down the vertical stratification of the water, allowing the mixture at different heights to fully blend and ensuring uniform distribution of the coagulant across the entire water volume, thus improving coagulation efficiency. Furthermore, a complex flow field is created, diversifying the liquid's flow path and increasing collision opportunities between fluid particles. The interweaving of water flows at different directions and speeds allows for more frequent contact between the coagulant and pollutant particles in the wastewater, promoting coagulation and flocculation reactions and contributing to the formation of larger, denser flocs. During floc formation, the up-and-down movement of the lifting frame 5 alters the speed and direction of the water flow, causing floc particles to move in different water flow environments. This brings together particles that were originally in different positions, increasing the probability of collisions between particles and promoting floc growth and aggregation. Furthermore, applying a certain shear force to the flocs makes the particles inside the flocs more compact and orderly. This well-structured floc has better settling performance, which is beneficial for subsequent solid-liquid separation processes and reduces sedimentation time and floor space requirements. Additionally, the water flow fluctuations generated by the lifting frame 5 during its movement can also flush the walls of the tank 1, reducing the adhesion and accumulation of flocs and impurities on the walls, keeping the tank walls clean, preventing scaling from adversely affecting coagulation, and maintaining good water flow conditions inside the tank 1.

[0051] The stirring assembly 2 includes a first bearing seat 21, a stirring shaft 22, and stirring blades 23. The first bearing seat 21 is fixed to the top of the housing 1. The lower part of the stirring shaft 22 passes through the first bearing seat 21 and the top wall of the housing 1, and extends into the interior of the housing 1 where two layers of stirring blades 23 are fixedly arranged vertically. The rotation of the stirring shaft 22 drives the stirring blades 23 to rotate, thereby improving the mixing efficiency.

[0052] The lifting component 4 includes a motor 41, a first rotating shaft 42, a first bevel gear 43, a second bevel gear 44, a second bearing seat 45, a second rotating shaft 46, a cam 47, a connecting frame 48, a guide sleeve 49, and a guide rod 410. The top of the housing 1 is fixed with the motor 41 and the second bearing seat 45. The top of the motor 41 is fixed with the first rotating shaft 42. The top of the first rotating shaft 42 is fixed with the first bevel gear 43. The left end of the second rotating shaft 46 is fixed with the second bevel gear 44, which meshes with the first bevel gear 43. The right end of the second rotating shaft 46 is fixed with the cam 47. The left and right sides of the top of the housing 1 are both fixed with guide sleeves 49. The bottom end of the guide rod 410 passes through the guide sleeve 49 and the top wall of the housing 1, and extends into the interior of the housing 1 where the lifting frame 5 is fixed. The left and right guide rods 410 are connected by the connecting frame 48. The cam 47 contacts the bottom wall of the connecting frame 48. The transmission assembly 3 includes a drive wheel 31, a driven wheel 32, and a transmission belt 33. The drive wheel 31 is fixed to the first rotating shaft 42, and the driven wheel 32 is fixed to the stirring shaft 22. The drive wheel 31 and the driven wheel 32 are connected by the transmission belt 33.

[0053] The rotation of motor 41 drives the first rotating shaft 42 to rotate, which in turn drives the first bevel gear 43 to rotate, which in turn drives the second bevel gear 44 to rotate, which in turn drives the second rotating shaft 46 to rotate, causing the cam 47 to rotate. Under the action of the cam 47 and gravity, the connecting frame 48 moves up and down reciprocally, which in turn drives the guide rod 410 to move up and down reciprocally, which in turn drives the lifting frame 5 to move up and down reciprocally. At the same time, the rotation of the first rotating shaft 42 drives the drive wheel 31 to rotate, which drives the driven wheel 32 to rotate through the transmission belt 33, causing the stirring shaft 22 to rotate. In this way, only one drive source (motor 41) is needed to realize the up and down reciprocating motion of the lifting frame 5 and the continuous stirring operation of the stirring blade 23. By linking the two actions, the liquid is disturbed while stirring, which effectively ensures that the coagulation and sedimentation process is complete.

[0054] The lifting frame 5 includes a ring 51, a first horizontal plate 52, a second horizontal plate 53, and a vertical plate 54. The first horizontal plate 52 is fixed to both the left and right side walls of the ring 51. The vertical plate 54 is fixed to the outer end of the first horizontal plate 52, and the second horizontal plate 53 is fixed to the inner side of the lower part of the vertical plate 54. The upper stirring blade 23 is located between the first horizontal plate 52 and the second horizontal plate 53, and the second horizontal plate 53 is located between the upper and lower stirring blades 23. The stirring shaft 22 passes through the ring 51, and the bottom end of the guide rod 410 is connected to the top end of the vertical plate 54. The spaces between the first horizontal plate 52 and the upper stirring blade 23, between the upper stirring blade 23 and the second horizontal plate 53, and between the second horizontal plate 53 and the lower stirring blade 23 form special flow field regions when the components move. The movement of the first horizontal plate 52 and the second horizontal plate 53 generates additional disturbance to the liquid around the stirring blade 23, making the vortex formed by the stirring blade 23 more complex. This complex flow field increases the collision frequency between fluid micro-clusters, allowing the coagulant to come into more full contact with the pollutant particles in the wastewater, thereby accelerating the coagulation and flocculation reaction.

[0055] The system also includes a medicine storage tank 6, a third bearing 7, a vertical pipe 8, a sealing ring 9, and a first valve 10. The medicine storage tank 6 is fixed to the top of the housing 1, and the bottom of the medicine storage tank 6 is fixedly connected to the vertical pipe 8. The vertical pipe 8 is equipped with the first valve 10. The stirring shaft 22 has a first cavity 221 inside, and the third bearing 7 is fixed to the upper part of the first cavity 221. The bottom end of the vertical pipe 8 passes through the third bearing 7. A sealing ring 9 is provided between the vertical pipe 8 and the side wall of the stirring shaft 22. The stirring blade 23 has a second cavity 231 inside that communicates with the first cavity 221. The front and rear side walls of the stirring blade 23 both have a first through hole 232 that communicates with the second cavity 231.

[0056] When coagulant needs to be added, the first valve 10 is opened and the coagulant enters the vertical pipe 8 from the storage tank 6, then enters the first cavity 221, and finally enters the tank 1 through the first through hole 232. The coagulant is added directly from the stirring end while stirring, which can ensure that the coagulant can be quickly and evenly dispersed in the wastewater in the tank 1.

[0057] It also includes an air pump 11, a connecting pipe 12, and a second valve 13. The air pump 11 is fixed on the top of the housing 1. The right side of the air outlet pipe of the air pump 11 is fixedly connected to the connecting pipe 12. The right end of the connecting pipe 12 is fixedly connected to the vertical pipe 8, and the connection point is located below the first valve 10. The connecting pipe 12 is equipped with a second valve 13.

[0058] When air supply is required, the air pump 11 and the second valve 13 are opened. The gas enters the vertical pipe 8 through the connecting pipe 12, then enters the first cavity 221, and finally is ejected through the first through hole 232. In this way, the ejected airflow breaks the laminar flow state of the liquid while stirring and mixing, allowing the coagulant and other components to disperse more quickly and evenly in the mixture. The complex and varied trajectories of the bubbles interact with the water flow generated by the stirring blades 23 and the lifting frame 5, further increasing the flow complexity of the mixture. This complex flow field allows for more thorough mixing of liquids in different areas, reducing potential concentration and velocity gradients in the mixture, and enabling the coagulation reaction to proceed under more uniform conditions. The bubbles generated by the injected airflow act as coagulation nuclei, attracting colloidal particles and fine suspended solids in the wastewater. These particles aggregate on the bubble surface, gradually forming tiny flocs. As the bubbles rise and the stirring blades 23 agitate, more particles are adsorbed onto the flocs, promoting floc growth. As bubbles rise, they exert buoyancy and impact on the flocs, subjecting them to continuous external forces during formation. These forces help the particles within the flocs to a tighter bond, enhancing the flocs' structural strength. Stable flocs are less prone to breakage during subsequent sedimentation, improving solid-liquid separation. The introduced gas creates sufficient dissolved oxygen, promoting oxidation reactions in the water. Certain pollutants are more easily removed by coagulants under aerobic conditions; for example, some reducing substances can be oxidized to more easily precipitated forms under dissolved oxygen. Furthermore, dissolved oxygen inhibits the growth of harmful microorganisms, preventing their negative impact on the coagulation process.

[0059] The system also includes a hose 14 and a third valve 15. The side wall of the ring 51 has a third cavity 511, which surrounds the ring 51. The first horizontal plate 52, the second horizontal plate 53, and the vertical plate 54 each have a fourth cavity 55. The fourth cavity 55 of the first horizontal plate 52 connects to the third cavity 511 and the fourth cavity 55 of the vertical plate 54. The fourth cavity 55 of the vertical plate 54 connects to the fourth cavities 55 of the vertical plate 54 and the second vertical plate 54. The front and rear side walls of the first horizontal plate 52, the second horizontal plate 53, and the vertical plate 54 each have a second through hole 56 that communicates with the fourth cavity 55 inside. One end of the hose 14 is fixedly connected to the left side of the air outlet pipe of the air pump 11, and the other end of the hose 14 is connected to the fourth cavity 55 of the first horizontal plate 52. The hose 14 is equipped with a third valve 15.

[0060] The third valve 15 can be opened simultaneously with the addition of chemicals, allowing gas to enter the fourth cavity 55 through the hose 14 and then be ejected from the second through hole 56. This combined operation of adding chemicals while stirring significantly improves the dispersion efficiency of the coagulant in the wastewater and enhances the mixing uniformity. Alternatively, the third valve 15 can be opened simultaneously with the second valve 13, or the third valve 15 can be opened while the second valve 13 and the first valve 10 are closed. The specific opening and closing of each valve is determined according to actual usage requirements, adapting to different operational needs and offering high flexibility. The gas ejected from the first through hole 232 and the second through hole 56 will have a certain scouring effect on the surfaces of the stirring blades 23 and the lifting frame 5. This prevents flocculents and impurities from adhering to and accumulating on the surfaces of the stirring blades 23 and the lifting frame 5, keeping them clean and ensuring normal operation.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum foil wastewater treatment system, characterized in that: It includes wastewater collection tanks, pretreatment equipment, ultrafiltration systems, nanofiltration systems, recovery tanks, and electrolytic cells; The outlet of the wastewater collection tank is connected to the pretreatment equipment; The supernatant outlet of the pretreatment equipment is connected to the ultrafiltration system; The product water outlet of the ultrafiltration system is connected to the nanofiltration system; The permeate outlet of the nanofiltration system is connected to the recovery tank, and the concentrate outlet of the nanofiltration system is connected to the electrolyzer. The pretreatment equipment includes a housing, a stirring assembly, a transmission assembly, a lifting component, and a lifting frame; The top of the box is fixed with a stirring assembly and a lifting component, and the stirring end of the stirring assembly is located inside the box. The lifting component is connected to the stirring component via a transmission assembly. The lifting end of the lifting component is fixed with a lifting frame, and the lifting frame is located inside the box body; The stirring assembly includes a first bearing housing, a stirring shaft, and stirring blades; The top of the box is fixed with a first bearing seat, and the lower part of the stirring shaft passes through the first bearing seat and the top wall of the box, and extends into the interior of the box where two layers of stirring blades are fixed at intervals. The lifting component includes a motor, a first rotating shaft, a first bevel gear, a second bevel gear, a second bearing seat, a second rotating shaft, a cam, a connecting frame, a guide sleeve, and a guide rod; The top of the housing is fixed with a motor and a second bearing seat; The top of the motor is fixed with a first rotating shaft, and the top of the first rotating shaft is fixed with a first bevel gear. A second bevel gear is fixed to the left end of the second rotating shaft, and the second bevel gear meshes with the first bevel gear. A cam is fixed to the right end of the second rotating shaft. Guide sleeves are fixed on both the left and right sides of the top of the box. The bottom end of the guide rod passes through the guide sleeve and the top wall of the box, and extends into the interior of the box where the lifting frame is fixed. The left and right guide rods are connected by a connecting bracket; The cam contacts the bottom wall of the connecting frame; The lifting frame includes a ring, a first horizontal plate, a second horizontal plate, and a vertical plate; The left and right side walls of the ring are each fixed with a first horizontal plate, the outer end of the first horizontal plate is fixed with a vertical plate, and the inner side of the lower part of the vertical plate is fixed with a second horizontal plate. The upper stirring blade is located between the first and second horizontal plates, and the second horizontal plate is located between the upper and lower stirring blades; The stirring shaft passes through the ring sleeve, and the bottom end of the guide rod is connected to the top end of the vertical plate; It also includes a medicine storage tank, a third bearing, a vertical pipe, a sealing ring, and a first valve; A medicine storage box is fixed to the top of the box body, and a vertical pipe is fixedly connected to the bottom of the medicine storage box. A first valve is provided on the vertical pipe. The stirring shaft has a first cavity inside, and a third bearing is fixed above the inside of the first cavity. The bottom end of the vertical tube passes through the third bearing; A sealing ring is provided between the vertical tube and the side wall of the stirring shaft; The stirring blade has a second cavity that communicates with the first cavity. The front and rear side walls of the stirring blade each have a first through hole communicating with the second cavity; It also includes an air pump, connecting pipes, a second valve, a hose, and a third valve; An air pump is fixed to the top of the box, and a connecting pipe is fixedly connected to the right side of the air pump's outlet pipe. The right end of the connecting pipe is fixedly connected to the vertical pipe, and the connection point is located below the first valve. The connecting pipe is equipped with a second valve; The sidewall of the ring sleeve has a third cavity; The first horizontal plate, the second horizontal plate, and the vertical plate each have a fourth cavity inside. The fourth cavity of the first horizontal plate is connected to the third cavity and the fourth cavity of the vertical plate. The fourth cavity of the vertical plate is connected to the fourth cavity of the second vertical plate; The front and rear side walls of the first horizontal plate, the second horizontal plate, and the vertical plate all have a second through hole communicating with the fourth cavity inside them; One end of the hose is fixedly connected to the left side of the air outlet pipe of the air pump, and the other end of the hose is connected to the fourth cavity of the first horizontal plate. The hose is equipped with a third valve.

2. The aluminum foil wastewater treatment system according to claim 1, characterized in that: The transmission assembly includes a driving wheel, a driven wheel, and a transmission belt; The driving wheel is fixed to the first rotating shaft, the driven wheel is fixed to the stirring shaft, and the driving wheel and the driven wheel are connected by a transmission belt.

3. A process for treating aluminum foil wastewater, characterized in that, The aluminum foil wastewater treatment system according to any one of claims 1-2 is used for treatment, comprising the following steps: Aluminum foil wastewater is sent to a wastewater collection tank. After homogenization and equalization in the wastewater collection tank, it is sent to a pretreatment device for pretreatment. The supernatant after pretreatment is sent to an ultrafiltration system for ultrafiltration treatment. The permeate obtained from ultrafiltration is sent to a nanofiltration system for nanofiltration treatment. The permeate obtained from nanofiltration is sent to a recovery tank to recover hydrochloric acid. The concentrated water obtained from nanofiltration is sent to an electrolytic cell for electrolysis treatment to obtain metallic aluminum.

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