A heavy metal detoxification and elution system and method for sediment sludge

Abstract

The application discloses a heavy metal detoxification and elution system for sediment sludge, which comprises a material grading system, a heavy metal pollution slurry particle size screening device, a heavy metal ion intensified leaching device for the enriched fine particle level high pollution slurry, a primary energy dissipation and thickening device, a supernatant heavy metal co-precipitation separation device, a high concentration slurry micro-electric field medium removal system, a micro-electric field medium removal system for high concentration slurry solid-liquid separation, a filtrate heavy metal co-precipitation separation device, a heavy metal co-precipitation separation device for supernatant and filtrate precipitation, a secondary energy dissipation and thickening device, a supernatant tail water treatment device, and a heavy metal precipitate slurry cake obtained by a pressure filtration device for precipitate mixed slurry. The application realizes heavy metal pollution deep elution through material grading pretreatment, heavy metal ion intensified leaching, thickening separation, micro-electric field solid-liquid two-phase separation and coupling heavy metal co-precipitation separation technology.

Description

Technical Field

[0001] This invention relates to the field of environmental dredging technology for polluted sediment in mine reservoirs or water sources, and particularly to a system for deep elution of heavy metals enriched in sediment sediment. Background Technology

[0002] With the acceleration of industrialization and urbanization, heavy metal pollution in sediments has become a significant factor affecting the safety of water sources. Sediments act as both a source and sink for water pollutants. Pollutants in water bodies accumulate and are stored in sediments over long periods. When the concentration reaches a certain threshold, these pollutants are continuously released back into the water, posing a serious threat to the ecological environment and human health. Therefore, the treatment of heavy metals in water bodies and sediments at water sources is a crucial measure to ensure water resource security.

[0003] Currently, the core of heavy metal remediation in water bodies is sediment treatment. Conventional methods in water environment management primarily involve dredging sediments to the shore, followed by simple solidification and dewatering of the mud-water mixture to lock the heavy metals within solid particles; or direct mechanical dewatering, mechanically pressing the entire mud slurry and incinerating the mud cake. However, heavy metals in sediments tend to concentrate in finer silty clay particles, while larger particles such as sand and shells show less concentration and pose no risk of endogenous release. Furthermore, sediment dredging initially creates a large mud-water mixture, consuming significant amounts of solidification agents during solidification and stabilization, and simultaneously discharging large quantities of wastewater containing heavy metals. Therefore, conventional treatment methods, on the one hand, increase treatment costs because they do not classify and treat sediments and use solidification methods for all sediments. At the same time, the solidified sediments still have a certain risk of secondary instability and need to be landfilled or properly disposed of, which poses a certain risk of environmental pollution. On the other hand, the large amount of tailwater generated needs to be safely treated. Furthermore, due to the strong adsorption of fine sludge particles, conventional pressing and dewatering cannot effectively remove heavy metals from the sludge, further increasing the overall treatment cost.

[0004] Therefore, the treatment of heavy metals in water bodies and sediments in mine reservoirs or water sources urgently requires breakthroughs in technical bottlenecks such as reasonable classification and pretreatment of sediment materials, elution of heavy metal pollutants, and deep solid-liquid separation, so as to thoroughly achieve the goals of detoxification, elution, and disposal. Summary of the Invention

[0005] To address the problems of unclear material classification, low heavy metal efficiency, incomplete dehydration, and difficulty in detoxifying heavy metals in filtrate in the existing technologies, this invention proposes a sediment sediment heavy metal detoxification and elution system and method. The system achieves deep elution of heavy metal pollution through material classification pretreatment, enhanced leaching of heavy metal ions, concentration separation, micro-electric field solid-liquid two-phase separation coupled with rapid co-precipitation separation technology for heavy metals.

[0006] The technical solution adopted in this invention is:

[0007] A sediment sediment heavy metal detoxification and elution system includes a material classification system, a heavy metal enhanced leaching device, a primary energy-dissipating and concentrating device, a micro-electric field desliming system, a heavy metal co-precipitation and separation device, a secondary energy-dissipating and concentrating device, a tailwater treatment device, and a filter press device.

[0008] The material classification system performs particle size screening on heavy metal contaminated slurry, removes large particle impurities and enriches fine-particle highly contaminated slurry into the heavy metal enhanced leaching device.

[0009] The heavy metal enhanced leaching device includes a homogenizing tank, which is connected to the I drug supply device. An activator is added to the homogenizing tank to form an acidic activation environment, thereby enhancing the leaching of heavy metal ions.

[0010] The feed inlet of the first-stage energy dissipation and concentration device is connected to the discharge outlet of the homogenization tank. The slurry that has undergone heavy metal enhanced leaching enters the first-stage energy dissipation and concentration device to achieve further energy dissipation, conditioning and thickening. The supernatant enriched with heavy metals after thickening and separation is discharged to the heavy metal co-precipitation separation device, and the high-concentration slurry is discharged to the micro-electric field desliming system.

[0011] The micro-electric field desliming system performs solid-liquid separation on high-concentration slurry to form a filter cake and a filtrate enriched with heavy metals, wherein the filtrate is discharged to the heavy metal co-precipitation separation device.

[0012] The heavy metal coprecipitation separation device performs heavy metal complexation coprecipitation treatment on the supernatant and filtrate enriched with heavy metals. The heavy metal coprecipitation separation device is connected to the II drug supply device. Complexing agents are added into the heavy metal coprecipitation separation device to achieve simultaneous precipitation of multiple heavy metal ions.

[0013] The inlet of the secondary energy dissipation and concentration device is connected to the outlet of the heavy metal co-precipitation and separation device to perform concentration separation of the precipitate. The supernatant after concentration separation is discharged to the tailwater treatment device, and the concentrated precipitate mixture is discharged to the filter press device for filter press treatment to obtain heavy metal precipitate cake.

[0014] In the above scheme, the material classification system includes a cyclone device and a vibrating screen device; the vibrating screen device includes a primary filter screen layer, a secondary filter screen layer, and a slurry storage tank; the heavy metal contaminated sludge first enters the primary filter screen layer with a filter particle size of N1, and the material larger than N1 is separated out, while the material smaller than N1 enters the undersize slurry storage tank; the cyclone device's cyclone inlet is connected to the slurry storage tank, and the undersize slurry from the primary filter screen layer enters the cyclone device with a classification particle size of N2, where N2 < N1. Fine particles smaller than N2 are discharged from the cyclone overflow pipe to the heavy metal enhanced leaching device, while coarse particles larger than N2 are discharged from the cyclone underflow outlet and enter the secondary filter screen layer with a filter particle size of N2.

[0015] In the above scheme, the material on the screen of the secondary filter screen is an impurity larger than N2, while the material smaller than N2 enters the under-screen storage tank and continues to be processed in a circulating grading process.

[0016] In the above scheme, the setting range of N1 is 5mm~10mm; the setting range of N2 is 40μm~45μm.

[0017] In the above scheme, the activator includes Activator No. 1 and Activator No. 2. Activator No. 1 is a strong acid complex agent; Activator No. 2 is a strong oxidizing complex agent.

[0018] In the above scheme, the primary energy dissipation and thickening device includes a mixing chamber, an overflow trough, a tapered thickening structure, a countercurrent energy dissipation inclined plate, and an underflow discharge port. The overflow trough is located at the top of the mixing chamber, the countercurrent energy dissipation inclined plate is located inside the mixing chamber and below the overflow trough, the feed inlet of the primary energy dissipation and thickening device is located on the mixing chamber and below the countercurrent energy dissipation inclined plate, the tapered thickening structure is located at the bottom of the mixing chamber, and the underflow discharge port is located at the bottom end of the tapered thickening structure.

[0019] In the above scheme, the countercurrent energy dissipation inclined plate includes multiple inclined plates arranged side by side at intervals, and the angle between the inclined plate and the vertical axis is in the range of 20°~30°.

[0020] In the above scheme, the micro-electric field desliming system includes a diaphragm filter press and an electrified filter cloth device. The filter chamber of the diaphragm filter press is equipped with the electrified filter cloth device to accelerate the efficient pressing and discharge of heavy metal ions with the filtrate. The electrified filter cloth device includes a positive electrode, a negative electrode, an internal wire, a positive filter cloth electrode, and a negative filter cloth electrode. The positive and negative filter cloth electrodes are respectively laid on the inner walls of both sides of the filter chamber. The positive and negative electrodes are respectively installed on the outside of the diaphragm filter press. The positive electrode is connected to the positive filter cloth electrode through the internal wire, and the negative electrode is connected to the negative filter cloth electrode through the internal wire.

[0021] In the above scheme, the energized filter cloth device also includes an insulating frame. The two ends of the positive filter cloth electrode and the negative filter cloth electrode are respectively fixedly connected to the insulating frame, and two adjacent insulating frames are pressed and sealed together with the adjacent plate.

[0022] In the above scheme, the diaphragm filter press includes a fixed end plate, a diaphragm plate, a solid plate, a fixed tail plate, a pressing gas channel, a slurry inlet channel, a drainage branch pipe, and a filtrate drainage channel. The diaphragm plate and the solid plate are alternately arranged between the fixed end plate and the fixed tail plate, forming a filter chamber with a certain cavity in the middle. High-concentration slurry enters the filter chamber through the slurry inlet channel. The diaphragm plate is hollow in the middle and its upper end is connected to the pressing gas channel. When high-pressure air enters the diaphragm plate, it expands and forms an outward squeezing action. The drainage branch pipe is set at the bottom of the diaphragm filter press and is connected to the filtrate drainage channel. The filtrate is discharged from the filtrate drainage channel through the drainage branch pipe.

[0023] In the above scheme, the structure of the secondary energy dissipation and concentration device is the same as that of the primary energy dissipation and concentration device.

[0024] In the above scheme, the press water from the filter press is discharged into the heavy metal co-precipitation separation device for circulating co-precipitation treatment.

[0025] In the above scheme, the complexing agent includes complexing agent No. 1 and complexing agent No. 2. Complexing agent No. 1 is a heavy metal composite precipitation material, used to chemically react with various heavy metals to form complex precipitation products; complexing agent No. 2 is an alkaline neutralizing material, used to adjust the pH to neutral while deeply precipitating difficult-to-precipitate metal ions.

[0026] This invention also proposes a method for detoxifying and eluting heavy metals from sediments, employing the aforementioned sediment heavy metal detoxification and elution system, comprising the following steps:

[0027] S1. The pollutant material is subjected to particle size screening and gravity classification to remove large particulate impurities and obtain a fine-particle, highly polluting phase.

[0028] S2. Inject the enriched fine-particle, highly polluted phase into the heavy metal enhanced leaching device, add a composite activator to form an acidic activation environment, and enhance the leaching of heavy metal ions.

[0029] S3. The slurry that has been leached with heavy metals is injected into the first-stage energy dissipation and concentration device. The supernatant enriched with heavy metals after thickening and separation is discharged to the heavy metal co-precipitation separation device, and the high-concentration slurry is discharged to the micro-electric field desliming system.

[0030] S4. High-concentration sludge is dewatered by high-pressure plate and frame pressing through a micro-electric field dewatering system. The filter cloth in the filter chamber is designed as a conductive, electrically conductive filter cloth device. A micro-electric field is constructed during the pressing and dewatering process. Under the synergistic effect of the micro-electric field, the dewatering of heavy metal ions is promoted, and the heavy metals are prevented from being reverse-adsorbed by the sludge cake particles. After solid-liquid separation, a filter cake and a filtrate enriched with heavy metals are formed. The filtrate is discharged to a heavy metal co-precipitation separation device.

[0031] S5. Add coprecipitant to the heavy metal coprecipitation separation device to perform heavy metal complexation coprecipitation treatment on the supernatant and filtrate enriched with heavy metals, so as to achieve simultaneous precipitation of multiple heavy metal ions.

[0032] S6. The precipitate obtained in S5 is injected into the secondary energy dissipation and thickening device in the form of mixed mud for secondary thickening and separation. The supernatant after thickening and separation is discharged to the tailwater treatment device, and the concentrated precipitate mixed slurry is discharged to the filter press device for filter press treatment to obtain stable heavy metal precipitate cake.

[0033] The above method also includes step S7, which involves guiding the press water from the filter press to a heavy metal co-precipitation separation device for circulating co-precipitation treatment.

[0034] The beneficial effects of this invention are:

[0035] 1. The sediment sediment heavy metal detoxification and elution system of the present invention achieves deep elution of heavy metal pollution through material classification and pretreatment, enhanced leaching of heavy metal ions, concentration separation, micro-electric field solid-liquid two-phase separation coupled with rapid co-precipitation separation technology for heavy metals. Firstly, based on the concentration distribution of heavy metal pollutants in the sediment, the sediment material is rationally classified and pretreated, which reduces the workload of deep treatment, improves efficiency, and lowers costs. Then, a high-efficiency activation technology for heavy metal pollutants is used to rapidly activate and release heavy metal pollutants from the sediment into the water body. The inclined plate of the high-efficiency counter-current energy-dissipating thickening device achieves efficient energy dissipation, enabling rapid concentration and sedimentation of particulate matter while reducing the turbidity of the supernatant. The concentrated slurry undergoes high-pressure pressing and dewatering in the micro-electric field dewatering system, and under the synergistic effect of the micro-electric field, heavy metal ion dewatering is promoted, preventing heavy metals from being reverse-adsorbed by the filter cake particles, thus obtaining a filter cake with extremely low residual free metal ions, reducing the risk of secondary pollution. Finally, rapid co-precipitation separation of heavy metal pollutants is used to precipitate and detoxify the heavy metals in the water body.

[0036] 2. By further installing a secondary energy-dissipating thickening device, a tailwater treatment device, and a filter press after the heavy metal co-precipitation separation device, the precipitate is further concentrated and separated in the secondary energy-dissipating thickening device. The supernatant after thickening is discharged to the tailwater treatment device, and the concentrated precipitate mixture is injected into the filter press for filtration treatment, thereby obtaining a stable heavy metal precipitate cake with extremely low residual levels of free metal ions, reducing the risk of secondary pollution. At the same time, the press water from the filter press is discharged to the heavy metal co-precipitation separation device for further circulation and co-sedimentation treatment, ensuring that the effluent quality meets the standards.

[0037] 3. To accelerate the efficient removal of heavy metals with the filtrate during pressing, the filter cloth of the micro-electric field dewatering system is designed as a conductive, electrically powered filter cloth device. During the pressing and dewatering process, a micro-electric field is constructed. Under the synergistic effect of the micro-electric field, the removal of heavy metal ions is promoted, preventing heavy metals from being reverse-adsorbed by the sludge particles, thus improving dewatering efficiency and reducing heavy metal residue in the sludge. Simultaneously, the conductive filter cloth has a simple structure, is easy to replace, and has low maintenance costs.

[0038] 4. The overall process system is closely integrated, the integrated process is highly operable, the equipment structure is reasonable, the modular design is compact, and it occupies little space. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the heavy metal detoxification and elution system for sediment bottom sediment of the present invention;

[0041] Figure 2 yes Figure 1 A schematic diagram of the material classification system shown in the figure;

[0042] Figure 3 yes Figure 1 A schematic diagram of the micro-electric field descaling system shown in the figure.

[0043] Figure 4 yes Figure 3 A schematic diagram of the energized filter cloth device in the micro-electric field desliming system shown.

[0044] Figure 5 yes Figure 4 Enlarged view of section A of the electrically powered filter cloth device shown.

[0045] In the diagram: 1. Cutter suction dredger; 101. Mud pipe;

[0046] 2. Hydrocyclone device; 201. Hydrocyclone overflow pipe; 202. Hydrocyclone inlet; 203. Hydrocyclone underflow outlet;

[0047] 3. Vibrating screening device; 301. Slurry inlet; 302. Lower coarse screen plate; 303. Upper fine screen plate; 304. Vibrating base; 305. Linear vibrating motor unit; 306. Slurry storage tank; 307. No. 1 mud pump; 308. No. 1 lifting pipe; 309. Composite shock absorber; 310. Upper fine sand; 311. Lower coarse slag;

[0048] 4. Heavy metal enhanced leaching device; 401. Mixing tank; 402. Stirring device; 403. No. 2 mud pump; 404. No. 2 riser pipe;

[0049] 5. Primary energy dissipation and thickening device; 501. Mixing bin; 502. Overflow trough; 503. Tapered thickening structure; 504. Countercurrent energy dissipation inclined plate; 505. Underflow discharge port; 506. No. 3 mud pump; 507. No. 3 riser pipe;

[0050] 6. Micro-electric field desliming system; 61. Diaphragm filter press device; 611. Fixed end plate; 612. Diaphragm plate; 613. Solid plate; 614. Fixed tail plate; 615. Filter chamber; 616. Pressing gas channel; 617. Slurry inlet channel; 618. Drainage branch pipe; 619. Filtrate drainage channel; 62. Electrolyzed filter cloth device; 621. Insulating frame; 622. Positive electrode; 623. Negative electrode; 624. Built-in wire; 625. Positive filter cloth electrode; 626. Negative filter cloth electrode; 63. Hydraulic device; 64. Slurry inlet; 65. Pressing air inlet; 66. Drainage pipe; 67. Filter cake;

[0051] 7. Heavy metal co-precipitation separation device; 701. Reaction tank; 702. Stirring blades; 703. Mud pump No. 4; 704. Lifting pipe No. 4;

[0052] 8. Secondary energy dissipation and thickening unit; 806. No. 5 mud pump; 807. No. 5 riser pipe; 808. Tailwater outlet;

[0053] 9. I. Drug supply device; 901. Activator No. 1; 902. Activator No. 2;

[0054] 10. II drug supply device; 1001. No. 1 complexing agent; 1002. No. 2 complexing agent;

[0055] 11. Wastewater treatment device;

[0056] 12. Filter press; 1201. Heavy metal precipitate cake. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] It should be noted that the illustrations provided in the embodiments of the present invention are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0059] In this invention, it should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive and distinguishing purposes and should not be construed as indicating or implying relative importance.

[0060] Furthermore, it should be noted that the features of the various embodiments of the present invention can be combined or integrated in whole or in part, and as those skilled in the art will understand, they can interact and operate in different ways. Each embodiment can be implemented independently of each other or in association with one another.

[0061] like Figure 1 As shown, an embodiment of the present invention provides a sediment sediment heavy metal detoxification and elution system, comprising a material classification system, a heavy metal enhanced leaching device 4, a primary energy-dissipating and concentrating device 5, a micro-electric field desliming system 6, a heavy metal co-precipitation and separation device 7, a secondary energy-dissipating and concentrating device 8, a first-stage chemical supply device 9, a second-stage chemical supply device 10, a tailwater treatment device 11, and a filter press device 12.

[0062] The material classification system primarily performs particle size sieving and gravity classification of materials, removing large particulate impurities and enriching fine-particle, highly contaminated phases. (See also...) Figure 1-2The system includes a cyclone device 2 and a vibrating screening device 3. The vibrating screening device 3 includes a slurry inlet 301, a lower coarse screen plate 302 (primary filtration screen), an upper fine screen plate 303 (secondary filtration screen), a vibrating base 304, a linear vibrating motor unit 305, a slurry storage tank 306, a No. 1 mud pump 307, a No. 1 lift pipe 308, and a composite shock absorber 309. The lower coarse screen plate 302, the upper fine screen plate 303, and the side plates are fixedly connected to form an integral screen frame. Four composite shock absorbers 309 are designed at the lower end of the screen frame and sit together on the upper support of the slurry storage tank 306. The vibrating base 304 is fixedly connected to the top of the screen frame, and the linear vibrating motor unit 305 is mounted on the vibrating base 304. Two parallel vibrating motors configured on the linear vibrating motor unit 305 rotate in opposite directions, forming a linear reciprocating inertial traction force, driving the entire screen frame to perform high-frequency linear vibration.

[0063] The sediment contaminated with heavy metals is first forcefully suctioned by a cutter suction dredger 1 and transported in the form of a mixed slurry through the mud pipe 101 to the sediment heavy metal detoxification and washing system on shore to achieve ecological and environmentally friendly dredging. The heavy metal contaminated mud enters the lower coarse screen plate 302 of the vibrating screening device 3, i.e., the primary filter screen layer, through the slurry inlet 301 connected to the mud pipe 101. The screen is designed with a 5mm filter particle size. Under the action of high-frequency vibration, impurities larger than 5mm can be separated, and materials smaller than 5mm enter the under-screen storage tank 306 to achieve the first-level classification of particle size. The undersize slurry is pumped by mud pump 307 through riser pipe 308 to hydrocyclone device 2. It enters the hydrocyclone at high speed through inlet 202, forming a swirling field. Within this field, material particles are subjected to a combination of gravity and centrifugal force. Fine particles smaller than the cut-off diameter of 45μm rise through the inner swirling flow to the overflow port and are discharged from overflow pipe 201. Extensive field studies have shown that heavy metal contaminated sediment is primarily enriched in fine clay particles smaller than 40μm. This embodiment uses 45μm as the grading particle size to achieve separation of highly contaminated particles. Simultaneously, low-contamination coarse particles larger than the cut-off diameter of 45μm collect at the bottom of the hydrocyclone under the influence of the outer swirling flow, forming a high-concentration coarse particle slurry, which is discharged from the underflow port 203 and enters the upper fine screen plate 303. The upper fine screen plate 303 is designed as a 45μm filter screen. Under the action of high frequency vibration, it can separate impurities larger than 45μm. Materials smaller than 45μm enter the under-screen storage tank 306 and continue to be recycled to complete the second-stage particle size classification.

[0064] like Figure 2As shown, the heavy metal-contaminated sludge enters the material classification system. After two stages of high-frequency vibrating screening and one stage of cyclone classification, it forms three types of materials: a lower layer of coarse slag (311) larger than 5 mm, an upper layer of fine sand (310) between 45 μm and 5 mm, and a fine clay sludge highly enriched with heavy metals. The first two materials have low heavy metal content and do not require detoxification treatment, thus greatly reducing the workload of subsequent heavy metal treatment processes and saving treatment costs.

[0065] See also Figure 1 The fine clay slurry contaminated with highly concentrated heavy metals is discharged through the hydrocyclone overflow pipe 201 to the heavy metal enhanced leaching device 4. The heavy metal enhanced leaching device 4 includes a homogenizing tank 401, which contains a built-in stirring device 402 and is connected to a chemical supply device 9. Activator 1 901 and Activator 2 902 are added to the homogenizing tank 401 through the chemical supply device 9, creating a strong redox acidic activation environment in the tank. This rapidly ionizes, leaches, neutralizes, and modifies the heavy metal elements. With the assistance of the powerful stirring device 402, efficient homogenization and activation are achieved, enhancing the leaching efficiency of heavy metal ions. After the heavy metal enhanced leaching, the heavy metal ions dissolve rapidly in the liquid phase in a free state, detaching from the solid particles.

[0066] See also Figure 1The slurry, after being leached with heavy metals, is pumped by mud pump No. 2 403 and enters the primary energy dissipation and thickening device 5 through riser pipe No. 2 404 for further energy dissipation, conditioning, and thickening. The primary energy dissipation and thickening device 5 includes a mixing chamber 501, an overflow trough 502, a tapered thickening structure 503, a countercurrent energy dissipation inclined plate 504, and an underflow discharge port 505. The overflow trough 502 is located at the top of the mixing chamber 501. The countercurrent energy dissipation inclined plate 504 is located inside the mixing chamber 501 and below the overflow trough 502, and includes multiple inclined plates arranged side by side. The feed inlet of the primary energy dissipation and thickening device 5 is located on the mixing chamber 501 and below the countercurrent energy dissipation inclined plate 504. The tapered thickening structure 503 is located at the bottom of the mixing chamber 501, and the underflow discharge port 505 is located at the bottom end of the tapered thickening structure 503. When the mixed slurry rapidly fills the mixing chamber 501 with the hydraulically miscible flow, the miscible flow encounters the counter-current energy-dissipating inclined plate 504 during its upward movement. As the slurry rises counter-currently from below, the obstruction of the inclined plate reduces its upward velocity and turbulence, thus canceling out energy. Solid particles begin to settle under gravity, while clear water, carrying a small amount of suspended particles, steadily rises and overflows along the gaps between the inclined plates. As the suspended particles climb along the inclined plates, they settle and adhere to the surface, accumulating to a certain thickness before sliding down in clumps. Simultaneously, the solid particles gradually settle and converge at the tapered thickening structure 503. Therefore, the efficient counter-current energy-dissipating thickening device can quickly achieve rapid energy dissipation of the hydraulically miscible flow of the mixed slurry under the action of the counter-current energy-dissipating inclined plate 504, resulting in rapid particle deposition and thickening. The supernatant enriched with heavy metals after thickening and separation is collected from the overflow trough 502 at the top of the mixing chamber 501 and discharged to the heavy metal co-precipitation separation device 7, while the high-concentration mud is discharged from the underflow discharge port 505 and injected into the micro-electric field desliming system 6 by the No. 3 mud pump 506 through the No. 3 riser pipe 507 under high pressure from the slurry inlet 64.

[0067] See also Figure 1 The micro-electric field desliming system 6 is used for solid-liquid separation of high-concentration slurry, forming a filter cake 67 with low water content and a filtrate highly enriched with heavy metals. The filtrate is discharged through a drain pipe 66 to the heavy metal co-precipitation separation device 7. See also Figure 3 The micro-electric field dewatering system 6 includes a diaphragm filter press 61, an electrically conductive filter cloth device 62, and a hydraulic device 63. The diaphragm filter press 61 is used to achieve high-pressure plate and frame pressing dewatering. The filter chamber of the diaphragm filter press 61 is equipped with an electrically conductive filter cloth device 62 to accelerate the efficient pressing and discharge of metals along with the filtrate. The hydraulic device 63 is used to provide clamping force to the diaphragm filter press 61.

[0068] The diaphragm filter press 61 includes a fixed end plate 611, a diaphragm plate 612, a solid plate 613, a fixed tail plate 614, a pressing gas channel 616, a slurry inlet channel 617, a drainage branch pipe 618, and a filtrate drainage channel 619. The diaphragm plate 612 and the solid plate 613 are alternately arranged between the fixed end plate 611 and the fixed tail plate 614, forming a filter chamber 615 with a certain cavity. High-concentration slurry enters the filter chamber 615 through the slurry inlet channel 617. The diaphragm plate 612 is hollow in the middle, and its upper end is connected to the pressing gas channel 616. When high-pressure air enters the diaphragm plate 612, it expands, creating an outward pressing action. A drainage branch pipe 618 is provided at the bottom of the diaphragm filter press 61, which is connected to the filtrate drainage channel 619. The filtrate is discharged from the filtrate drainage channel 619 through the drainage branch pipe 618. The filtrate drainage channel 619 is connected to a drainage pipe 66, which is connected to a heavy metal co-precipitation separation device 7. The pressing gas passage 616 is connected to the pressing air inlet 65, which can be connected to a high-pressure gas source.

[0069] Some free heavy metal ions remain in the mud cake particles. Because the mud cake particles are fine powder with a large specific surface area and strong adsorption capacity, some of these free heavy metal ions will be re-adsorbed onto the particle surface during the pressing and dewatering process, making it difficult to separate these free heavy metals. To accelerate the efficient pressing and discharge of heavy metals with the filtrate, this invention designs the filter cloth of filter chamber 615 as a conductive, electrically powered filter cloth device 62. For example... Figure 4-5 As shown, the electrified filter cloth device 62 includes a positive electrode 622, a negative electrode 623, an internal wire 624, a positive filter cloth electrode 625, and a negative filter cloth electrode 626. The positive filter cloth electrode 625 and the negative filter cloth electrode 626 are respectively laid on the inner walls of both sides of the filter chamber 615, and the positive electrode 622 and the negative electrode 623 are respectively installed on the outside of the diaphragm filter press device 61. The positive electrode 622 is connected to the positive filter cloth electrode 625 through the internal wire 624, and the negative electrode 623 is connected to the negative filter cloth electrode 626 through the internal wire 624, forming a stable electric field. The electrified filter cloth device 62 also includes an insulating frame 621. The two ends of the positive filter cloth electrode 625 and the negative filter cloth electrode 626 are respectively welded to the insulating frame 621, and adjacent insulating frames 621 and adjacent plates are pressed and sealed together. The insulating frame 621 is made of insulating flexible material. Its function is to be welded together with the conductive electrode filter cloth to play a fixing role and to form an insulating area at the edge to avoid direct contact and short circuit between adjacent positive and negative electrodes.

[0070] The diaphragm filter press device 61 and the electrically conductive filter cloth device 62 together form a micro-electric field filter press function. During the pressing and dewatering process, a micro-electric field is constructed. Under the synergistic effect of the micro-electric field, the removal of heavy metal ions is promoted, preventing heavy metals from being reverse-adsorbed by the sludge cake particles, thereby improving dewatering efficiency and reducing heavy metal residues in the sludge cake. Figure 1 and Figure 3As shown, when the slurry to be pressed enters the filter press system through the dual inlet channel 617, it quickly fills the filter chamber 615. Solid particles are filtered and intercepted by the positive filter cloth electrode 625 and the negative filter cloth electrode 626 to form a filter cake. The clean water passes through the filter cloth and is discharged from the filtrate drainage channel 619 through the drainage branch pipe 618. As slurry continues to enter, after a high-density filter cake is formed in the filter chamber 615, the dual inlet channel 617 is closed. High-pressure air is connected through the pressing gas channel 616 and enters the diaphragm plate 612 to expand, forming an outward squeezing action, further discharging the filtrate with highly enriched heavy metals and reducing the moisture content of the slurry cake. During the pressing process, in the same chamber, two electrically conductive filter cloths are connected to external positive and negative electrodes 623 respectively through built-in wires 624 and equipped with a DC power supply to form a stable micro electric field, which causes heavy metal ions to accumulate towards the electrode filter cloth, reducing the phenomenon of heavy metal reverse adsorption. During the membrane pressing and dehydration process, they are discharged with the filtrate, improving the descaling rate of ionized heavy metals and forming a low-pollution filter cake 67, thus achieving the goal of efficient detoxification of bottom mud.

[0071] See also Figure 1 The supernatant and filtrate from the primary energy-absorbing concentration unit 5 and the micro-electric field desliming system 6, which contain almost all the heavy metals, are drawn into the heavy metal co-precipitation separation unit 7 for heavy metal complexation co-precipitation treatment. The heavy metal co-precipitation separation unit 7 includes a reaction tank 701 and a stirring blade 702 installed in the reaction tank 701. A secondary dosing device 10 is installed above the reaction tank 701. Co-precipitating agents, namely complexing agent 1001 and complexing agent 1002, are added to the heavy metal co-precipitation separation unit 7 through the secondary dosing device 10 to achieve simultaneous and rapid precipitation of multiple heavy metal ions, forming a very stable precipitate and achieving stabilization treatment.

[0072] See also Figure 1 The secondary energy dissipation and thickening unit 8 has the same structure as the primary energy dissipation and thickening unit 5. Its inlet is connected to the outlet of the heavy metal co-precipitation and separation unit 7. The precipitate, in the form of mixed slurry, is transported to the secondary energy dissipation and thickening unit 8 by mud pump 703 through riser 704 for secondary thickening and separation. Under the action of counter-current energy dissipation inclined plate 504, the hydraulic mixed flow rapidly dissipates energy, and the solid precipitate begins to settle and concentrate under the action of gravity. The supernatant after thickening and separation is discharged from the tailwater outlet 808 of overflow tank 502 to tailwater treatment unit 11; the concentrated precipitate mixed slurry is injected into filter press 12 by mud pump 806 through riser 807 for filter press treatment, thereby obtaining a stable heavy metal precipitate cake 1201. The heavy metal precipitate cake 1201 has a very low residual amount of free metal ions, reducing the risk of secondary pollution. Meanwhile, the pressed water from the filter press 12 is discharged into the heavy metal co-precipitation separation device 7 for continued circulation and co-precipitation treatment to ensure that the effluent water quality meets the standards.

[0073] The system of this invention ultimately forms low-leaching, high-enrichment heavy metal precipitated sludge (heavy metal precipitate cake 1201), low-pollution coarse particle slag on the screen (lower layer coarse slag 311, upper layer fine sand 310), low-pollution detoxification and demediuming cake, and effluent that meets discharge standards, thus achieving efficient detoxification of bottom sediment, enrichment of heavy metal pollutants, and safe disposal of effluent that meets discharge standards.

[0074] Further optimization resulted in the secondary energy dissipation and concentration device 8 having the same structure as the primary energy dissipation and concentration device 5.

[0075] To further optimize the design and avoid particle blockage, the angle between the counter-current energy dissipation inclined plate 504 and the vertical axis is designed to be 20°-30°, while maintaining a certain gap.

[0076] Further optimization resulted in activator No. 1 being a strong acid complex agent and activator No. 2 being a strong oxidizing complex agent (such as ferrous salt or iron-manganese-based oxidant).

[0077] Further optimizations were made: Complexing agent No. 1 is a heavy metal composite sedimentation material that reacts chemically with various heavy metals to form complex precipitates; Complexing agent No. 2 is an alkaline neutralizing material that adjusts the pH to neutral while focusing on the deep sedimentation of difficult-to-precipitate metal ions.

[0078] Accordingly, this invention also proposes a method for detoxifying and eluting heavy metals in sediment, using the aforementioned sediment heavy metal detoxification and elution system, comprising the following steps:

[0079] S1. The pollutant material is subjected to particle size screening and gravity classification to remove large particulate impurities and obtain a fine-particle, highly polluting phase.

[0080] S2. Inject the enriched fine-particle, highly polluted phase into the heavy metal enhanced leaching device 4, add a composite activator to form an acidic activation environment, and enhance the leaching of heavy metal ions.

[0081] S3. The slurry that has been leached with heavy metals is injected into the first-stage energy dissipation and concentration device 5. The supernatant enriched with heavy metals after thickening and separation is discharged to the heavy metal co-precipitation separation device 7. The high-concentration slurry is discharged to the micro-electric field desliming system 6.

[0082] S4. High-concentration sludge is dewatered by high-pressure plate and frame pressing through the micro electric field dewatering system 6, and the filter cloth of the filter chamber is designed as a conductive electric filter cloth device 62. A micro electric field is constructed during the pressing and dewatering process. Under the synergistic effect of the micro electric field, the dewatering of heavy metal ions is promoted to avoid the reverse adsorption of heavy metals by the sludge cake particles. After solid-liquid separation, a filter cake and a filtrate enriched with heavy metals are formed. The filtrate is discharged to the heavy metal coprecipitation separation device 7.

[0083] S5. Add coprecipitant to heavy metal coprecipitation separation device 7 to perform heavy metal complexation coprecipitation treatment on the supernatant and filtrate enriched with heavy metals, so as to achieve simultaneous precipitation of multiple heavy metal ions.

[0084] S6. The precipitate obtained in S5 is injected into the secondary energy dissipation thickening device 8 in the form of mixed mud for secondary thickening separation. The supernatant after thickening separation is discharged to the tailwater treatment device 11, and the concentrated precipitate mixed slurry is discharged to the filter press device 12 for filter press treatment to obtain stable heavy metal precipitate cake.

[0085] S7. The pressed water from the filter press 12 is discharged into the heavy metal co-precipitation separation device 7 for circulating co-precipitation treatment.

[0086] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0087] The order of the steps in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0088] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A sediment sludge heavy metal detoxification elution system, characterized in that, It includes a material classification system, a heavy metal enhanced leaching device, a primary energy-dissipating and concentrating device, a micro-electric field desliming system, a heavy metal co-precipitation and separation device, a secondary energy-dissipating and concentrating device, a tailwater treatment device, and a filter press device; The material classification system performs particle size screening on heavy metal contaminated sludge, removing large particles and enriching fine-particle, highly contaminated sludge into the heavy metal enhanced leaching device. The material classification system includes a cyclone device and a vibrating screen device. The vibrating screen device includes a primary filter screen, a secondary filter screen, and a sludge storage tank. The heavy metal contaminated sludge first enters the primary filter screen with a filter particle size of N1. Materials larger than N1 are separated, and materials smaller than N1 enter the undersize sludge storage tank. The cyclone device's cyclone inlet is connected to the sludge storage tank. The undersize sludge from the primary filter screen enters the cyclone device with a classification particle size of N2. N2 < N1. Fine particles smaller than N2 are discharged from the cyclone overflow pipe to the heavy metal enhanced leaching device, while coarse particles larger than N2 are discharged from the cyclone underflow outlet and enter the secondary filter screen with a filter particle size of N2. The heavy metal enhanced leaching device includes a homogenizing tank, which is connected to the I drug supply device. An activator is added to the homogenizing tank to form an acidic activation environment, thereby enhancing the leaching of heavy metal ions. The feed inlet of the first-stage energy dissipation and concentration device is connected to the discharge outlet of the homogenization tank. The slurry that has undergone heavy metal enhanced leaching enters the first-stage energy dissipation and concentration device to achieve further energy dissipation, conditioning and thickening. The supernatant enriched with heavy metals after thickening and separation is discharged to the heavy metal co-precipitation separation device, and the high-concentration slurry is discharged to the micro-electric field desliming system. The micro-electric field desliming system performs solid-liquid separation on high-concentration slurry, forming a filter cake and a filtrate enriched with heavy metals. The filtrate is then discharged to the heavy metal co-precipitation separation device. The micro-electric field desliming system includes a diaphragm filter press and an electrically conductive filter cloth device. The filter chamber of the diaphragm filter press is equipped with the electrically conductive filter cloth device to accelerate the efficient pressing and discharge of heavy metal ions with the filtrate. The electrically conductive filter cloth device includes a positive electrode, a negative electrode, an internal wire, a positive filter cloth electrode, and a negative filter cloth electrode. The positive and negative filter cloth electrodes are respectively laid on the inner walls of both sides of the filter chamber. The positive and negative electrodes are respectively installed on the outside of the diaphragm filter press. The positive electrode is connected to the positive filter cloth electrode through the internal wire, and the negative electrode is connected to the negative filter cloth electrode through the internal wire. The heavy metal coprecipitation separation device performs heavy metal complexation coprecipitation treatment on the supernatant and filtrate enriched with heavy metals. The heavy metal coprecipitation separation device is connected to the II drug supply device. Complexing agents are added into the heavy metal coprecipitation separation device to achieve simultaneous precipitation of multiple heavy metal ions. The inlet of the secondary energy dissipation and concentration device is connected to the outlet of the heavy metal co-precipitation and separation device to perform concentration separation of the precipitate. The supernatant after concentration separation is discharged to the tailwater treatment device, and the concentrated precipitate mixture is discharged to the filter press device for filter press treatment to obtain heavy metal precipitate cake.

2. The sediment sludge heavy metal detoxification elution system according to claim 1, characterized in that, The material on the screen of the secondary filter layer consists of impurities larger than N2, while the material smaller than N2 enters the under-screen storage tank for further recycling and grading.

3. The sediment sludge heavy metal detoxification elution system according to claim 1, characterized in that, The setting range for N1 is 5mm to 10mm; the setting range for N2 is 40μm to 45μm.

4. The sediment sludge heavy metal detoxification elution system according to claim 1, characterized in that, The activator includes Activator No. 1 and Activator No.

2. Activator No. 1 is a strong acid complex agent, and Activator No. 2 is a strong oxidizing complex agent.

5. The sediment sludge heavy metal detoxification elution system according to claim 1, wherein, The primary energy dissipation and thickening device includes a mixing chamber, an overflow trough, a tapered thickening structure, a counter-current energy dissipation inclined plate, and an underflow discharge port. The overflow trough is located at the top of the mixing chamber, the counter-current energy dissipation inclined plate is located inside the mixing chamber and below the overflow trough, the feed inlet of the primary energy dissipation and thickening device is located on the mixing chamber and below the counter-current energy dissipation inclined plate, the tapered thickening structure is located at the bottom of the mixing chamber, and the underflow discharge port is located at the bottom end of the tapered thickening structure.

6. The sediment sludge heavy metal detoxification elution system according to claim 5, characterized in that, The counter-current energy dissipation inclined plate includes multiple inclined plates arranged side by side at intervals, with the angle between the inclined plate and the vertical axis ranging from 20° to 30°.

7. The sediment heavy metal detoxification and elution system according to claim 1, characterized in that, The electrically conductive filter cloth device also includes an insulating frame. The two ends of the positive and negative filter cloth electrodes are respectively fixedly connected to the insulating frame, and two adjacent insulating frames are pressed and sealed together with the adjacent plate.

8. The sediment heavy metal detoxification and elution system according to claim 1, characterized in that, The diaphragm filter press includes a fixed end plate, a diaphragm plate, a solid plate, a fixed tail plate, a pressing gas channel, a slurry inlet channel, a drainage branch pipe, and a filtrate drainage channel; the diaphragm plate and the solid plate are alternately arranged between the fixed end plate and the fixed tail plate, forming a filter chamber with a certain cavity in the middle, and high-concentration slurry enters the filter chamber through the slurry inlet channel; The diaphragm plate is hollow in the middle and its upper end is connected to the pressing gas channel. When high-pressure air enters the diaphragm plate, it expands and forms an outward squeezing action. The bottom of the diaphragm filter press is provided with a drainage branch pipe that is connected to the filtrate drainage channel. The filtrate is discharged from the filtrate drainage channel through the drainage branch pipe.

9. The sediment heavy metal detoxification and elution system according to claim 1, characterized in that, The structure of the secondary energy dissipation and concentration device is the same as that of the primary energy dissipation and concentration device.

10. The sediment heavy metal detoxification and elution system according to claim 1, characterized in that, The press water from the filter press is discharged into the heavy metal co-precipitation separation device for circulating co-precipitation treatment.

11. The sediment heavy metal detoxification and elution system according to claim 1, characterized in that, The complexing agent includes Complexing Agent No. 1 and Complexing Agent No.

2. Complexing Agent No. 1 is a heavy metal composite precipitation material, used to chemically react with various heavy metals to form complex precipitates. Complexing Agent No. 2 is an alkaline neutralizing material, used to adjust the pH to neutral while deeply precipitating difficult-to-precipitate metal ions.

12. A method for detoxifying and eluting heavy metals from sediment bottom sediment, characterized in that, The sediment heavy metal detoxification and elution system according to any one of claims 1-11 includes the following steps: S1. The pollutant material is subjected to particle size screening and gravity classification to remove large particulate impurities and obtain a fine-particle, highly polluting phase. S2. Inject the enriched fine-particle, highly polluted phase into the heavy metal enhanced leaching device, add a composite activator to form an acidic activation environment, and enhance the leaching of heavy metal ions. S3. The slurry that has been leached with heavy metals is injected into the first-stage energy dissipation and concentration device. The supernatant enriched with heavy metals after thickening and separation is discharged to the heavy metal co-precipitation separation device, and the high-concentration slurry is discharged to the micro-electric field desliming system. S4. High-concentration sludge is dewatered by high-pressure plate and frame pressing through a micro-electric field dewatering system. The filter cloth in the filter chamber is designed as a conductive, electrically conductive filter cloth device. A micro-electric field is constructed during the pressing and dewatering process. Under the synergistic effect of the micro-electric field, the dewatering of heavy metal ions is promoted, and the heavy metals are prevented from being reverse-adsorbed by the sludge cake particles. After solid-liquid separation, a filter cake and a filtrate enriched with heavy metals are formed. The filtrate is discharged to a heavy metal co-precipitation separation device. S5. Add coprecipitant to the heavy metal coprecipitation separation device to perform heavy metal complexation coprecipitation treatment on the supernatant and filtrate enriched with heavy metals, so as to achieve simultaneous precipitation of multiple heavy metal ions. S6. The precipitate obtained in S5 is injected into the secondary energy dissipation and thickening device in the form of mixed mud for secondary thickening and separation. The supernatant after thickening and separation is discharged to the tailwater treatment device, and the concentrated precipitate mixed slurry is discharged to the filter press device for filter press treatment to obtain stable heavy metal precipitate cake.

13. The method for detoxifying and eluting heavy metals from sediment bottom mud according to claim 12, characterized in that, It also includes step S7, which involves guiding the press water from the filter press to the heavy metal co-precipitation separation device for circulating co-precipitation treatment.

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