Remediation device for soil heavy metal pollution remediation and use method thereof

Abstract

The invention relates to the field of soil pollution remediation, and discloses a remediation device for soil heavy metal pollution remediation and a using method thereof.The remediation device for soil heavy metal pollution remediation comprises an acid mist absorption tower which is arranged on the top face of the ground; a purifying assembly, a crushing assembly, a screening assembly, a humidifying assembly, a transferring assembly, a stirring assembly and a protecting assembly are arranged on the ground. According to the remediation method for soil heavy metal pollution remediation, pollution in soil is effectively detoxified through screening and crushing, reduction reaction, deacidification, neutralization reaction, dehydration and re-burying, the original pollution in a soil leachate is larger than or equal to 2000 mg / kg, the total chromium content is larger than or equal to 10000 mg / kg and is reduced to be smaller than or equal to 3 mg / L, the total chromium content is smaller than or equal to 9 mg / L, Ni is smaller than or equal to 50 mg / L, meanwhile, the pH ranges from 6 to 9, and the remediation effect is good. And acid mist generated in the reduction reaction process can be pumped into the acid mist absorption tower by the anti-corrosion induced draft fan, is neutralized by alkali in the acid mist absorption tower, and is discharged after reaching the discharge standard through the discharge pipe.

Description

Technical Field

[0003]

[0001] The present invention relates to the technical field of soil pollution remediation, and specifically to a remediation device for soil heavy metal pollution and its use method. Background Technique

[0002] Soil heavy metal pollution remediation refers to the process of reducing or removing excessive heavy metals (such as cadmium, lead, arsenic, mercury, etc.) in soil through physical, chemical, biological or combined technologies to restore the ecological function of the soil and ensure human health.

[0003] According to the Chinese patent with the publication number CN207276341U, a water treatment system for heavy metal contaminated soil leaching solution includes a water treatment equipment group consisting of four reaction tanks connected in sequence: an agglomeration tank, a heavy metal reaction tank, a pH adjustment tank, and a flocculation tank, and also includes a dissolution and dosing device for water treatment supporting the water treatment equipment group, including a PAM dissolution and dosing tank, a heavy metal capturer dissolution and dosing tank, a sulfuric acid dissolution and dosing tank, a PAC dissolution and dosing tank, and a liquid alkali dissolution and dosing tank.

[0004] In the above solution, sulfuric acid is used to participate in the reduction reaction of the soil, resulting in the following disadvantages: when sulfuric acid participates in the reduction reaction of severely polluted soil, a large amount of acid mist will be generated, and the direct emission of these acid mists will pollute the nearby air environment. Summary of the Invention

[0005] The purpose of the present invention is to provide a remediation device for soil heavy metal pollution and its use method to solve the problem that when sulfuric acid participates in the reduction reaction of severely polluted soil, a large amount of acid mist will be generated, and the direct emission of these acid mists will pollute the nearby air environment.

[0006] To achieve the above invention purpose, the present invention adopts the following technical scheme: A remediation device for soil heavy metal pollution includes an acid mist absorption tower, the acid mist absorption tower is arranged on the top surface of the ground, and a purification component, a crushing component, a screening component, a humidifying component, a transfer component, a stirring component, and a protection component are arranged on the ground. The purification component is connected to a reduction reaction tank through the stirring component; The purification component includes a detachable closed cover arranged on the top surface of the reduction reaction tank. A connecting pipe is fixed on the top surface of the closed cover, and the other end of the connecting pipe is fixed to the top end of the acid mist absorption tower. A number of anti-corrosion induced draft fans are arranged on the acid mist absorption tower. A discharge pipe penetrates through the acid mist absorption tower. A crushing component for crushing soil is arranged on the ground. A screening component for screening soil is arranged on the ground. A humidifying component for injecting water is arranged on the ground. A transfer component for storing slurry is arranged on the ground. A stirring component for stirring the slurry is arranged in the reduction reaction tank. A protection component for storing sulfuric acid is arranged on the ground. When Restore to When the acid mist is generated, it will be drawn into the acid mist absorption tower by the anti-corrosion induced draft fan. Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower. When the gas meets the emission standards, it will be discharged from the inside of the acid mist absorption tower through the emission pipe.

[0007] Through the above technical solution, the crushed slurry is added into the reduction reactor. An appropriate amount of 98% concentrated sulfuric acid and a saturated ferrous sulfate solution are added to the inside of the reduction reactor. When the pH value of the mixed slurry inside the reduction reactor reaches a certain level, the reaction can proceed. Restore to During the reduction process, 98% concentrated sulfuric acid is added. The resulting acid mist is drawn into the acid mist absorption tower by the anti-corrosion fan. After being neutralized by alkali inside the acid mist absorption tower, it is discharged through the discharge pipe after meeting the emission standards, thus increasing the safety of the emitted gas.

[0008] Preferably, the crushing assembly includes a storage box disposed on the ground, two bases disposed on the ground, a ball mill disposed on the ground, the bases being fixedly installed on the bottom surface of the ball mill, a belt conveyor disposed inside the storage box, a plurality of arc-shaped plates being fixed on the surface of the belt conveyor, two supporting folding plates being fixed on the surface of the ball mill, and the belt conveyor being disposed between the two supporting folding plates.

[0009] Through the above technical solution, the heavily contaminated soil inside the storage box will be fed into the ball mill by the belt conveyor during operation. The soil inside the ball mill will be processed into slurry, increasing the contact area between the soil and the reactants and increasing the reaction rate.

[0010] Preferably, the screening assembly includes two positioning plates disposed on the top surface of the storage box, an installation frame hinged between the two positioning plates, an inclined screen disposed inside the installation frame, and two support plates fixed on the top surface of the storage box, one side of the support plate being fixed to one side of the installation frame.

[0011] Using the above technical solution, the excavated heavily contaminated soil is dumped onto an inclined screen, which uses a certain angle to remove impurities and foreign objects from the soil, thus preventing these impurities from interfering with subsequent reactions.

[0012] Preferably, the humidification assembly includes two fixed plates mounted on the ball mill. The ball mill is equipped with a water tank, and a water pump is mounted on the bottom surface of the water tank. A water injection pipe is fixed to the drain pipe of the water pump. A water injection hole is opened on the surface of the ball mill. The bottom end of the water injection pipe passes through the bottom surface of the water tank and extends into the interior of the ball mill through the water injection hole. An addition hole is opened on the top surface of the water tank, and an addition pipe is fixed on the top surface of the water tank. The central axis of the addition hole and the addition pipe are aligned with each other.

[0013] With the above technical solution, when the ball mill is crushing heavily polluted soil, the water in the water tank will be pumped into the water injection pipe and injected into the ball mill. This allows for the quantitative addition of water while crushing the soil, resulting in a particle size of 200 mesh after 98% crushing, thus increasing the precision of the material during crushing.

[0014] Preferably, the transfer component includes a sliding opening on the ground, a storage box is slidably disposed inside the sliding opening, a fixing frame is fixed on the top surface of the storage box, and a plurality of mounting openings are provided on the ground, with rollers rotatably disposed inside the mounting openings.

[0015] Through the above technical solution, the slurry produced by the ball mill is discharged into the interior of the storage box. When the storage box is full and slides inside the sliding port, the bottom surface of the fixed frame will roll on the roller, reducing the friction of the storage box when it moves.

[0016] Preferably, the stirring assembly includes a motor disposed on the bottom surface of the reduction reaction vessel, the output shaft of the motor being rotatably inserted into the bottom surface of the reduction reaction vessel, a rotating shaft being fixed on the output shaft of the motor, and a plurality of stirring plates being fixed on the surface of the rotating shaft.

[0017] With the above technical solution, when the slurry reacts inside the reduction reaction tank, the output shaft of the motor will drive the rotating shaft to rotate synchronously, which will drive the stirring plate to stir the slurry inside the reduction reaction tank, so that the slurry and reactants can be in full contact.

[0018] Preferably, the protective assembly includes an underground sulfuric acid tank installed on the ground, with a cover plate mounted on the ground via a hinge.

[0019] Through the above technical solution, sulfuric acid, whether reacted or unreacted, is stored inside an underground sulfuric acid tank, and a cover plate is used to cover the underground sulfuric acid tank to prevent passing workers from falling into the underground sulfuric acid tank, thus increasing the safety of the workers.

[0020] Preferably, the protective assembly further includes two fixed posts fixed to the ground, a connecting plate fixed to one side of the cover plate, a limit opening opened on one side of the connecting plate, a rotating post fixed to the top of the fixed posts, and a limit plate rotatably sleeved on the rotating post.

[0021] With the above technical solution, when the cover plate is placed on the underground sulfuric acid tank, the fixing column will be inside the limiting port. Then, the staff will rotate the limiting plate and use the cross setting of the limiting plate and the limiting port to fix the position of the connecting plate on the ground.

[0022] This invention also provides a remediation method for a soil heavy metal pollution remediation device, the specific steps of which are as follows: Step 1: The heavily contaminated soil that was excavated ( Soil containing ≥2000mg / kg of chromium and ≥10000mg / kg of total chromium is poured onto an inclined screen to remove impurities. The screened soil falls into a storage box and is then conveyed by a belt conveyor into a ball mill. The ball mill crushes the soil, while a water pump injects water from a tank into the mill. The particle size of the soil or chromium slag entering the ball mill must be ≤10mm, and it must be free of impurities such as bricks, stones, cement, and plastics. The slag volume entering the ball mill is 10-20t / h, and the water volume is 15-30t / h. The solid-liquid content of the slurry discharged from the ball mill is 30%-60%. Step Two: The heavily contaminated soil, after being ground in a ball mill, is made into a slurry. This slurry is then added to a reduction reactor. A suitable amount of 98% concentrated sulfuric acid and ferrous sulfate saturated solution is added to the reactor at a mass ratio of 0.2:1. The pH value is monitored; when the pH of the mixed slurry reaches 4-5, the reduction reaction has reached its endpoint. The dissolved... Fully restored to The entire reduction reaction takes no less than 8 hours, and the final leachate contains... ≤3mg / L, total chromium ≤9mg / L, and Ni ≤50mg / L, while pH is within the range of 6~9. After sampling and testing the reduced slurry, it was ensured that... After passing the inspection, proceed to the next stage of the process; Step 3, ensuring After passing the test, the generated acid mist will be drawn into the acid mist absorption tower by the anti-corrosion fan. Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower. When the gas meets the emission standard, it will be discharged from the inside of the acid mist absorption tower through the emission pipe. At this time, the pH of the slurry is 6~9. Step 4: After taking out 98% concentrated sulfuric acid from the underground sulfuric acid tank, the staff will put the cover plate on the underground sulfuric acid tank, drive the fixing column to be inserted into the limit port, and use the limit plates that cross on the limit port to fix the connecting plate to the ground. Step 5: The mixed slurry completed in the reduction stage will be added to the neutralization reaction tank, and slaked lime milk for neutralization reaction will be added to the neutralization reaction tank. After thorough stirring, the pH of the slurry in the neutralization reaction tank will be adjusted to about 6-7, which is the end point of the neutralization reaction. The pH will be kept constant for half an hour while stirring. The entire neutralization reaction time will be no less than 1 hour. Then the neutralized slurry will be discharged and solid-liquid separation will be carried out through a high-pressure diaphragm plate and frame filter press. Step 6: Use a slurry pump to pump the slurry to the high-pressure diaphragm plate and frame filter press in the dewatering workshop for solid-liquid separation. The resulting filter cake has a moisture content of about 50%, and is then transferred to the inspection plant for temporary storage. Step 7: The wastewater after solid-liquid separation will be injected into the sedimentation pipe. At the same time, the chromium slag to be tested in the wastewater will be settled by static sedimentation. After preliminary sedimentation, the supernatant will be pumped out by the metering pump and reused in the ball mill and reduction reaction tank.

[0023] Compared with existing technologies, the remediation device and its application method for soil heavy metal pollution remediation using the above-mentioned technical solution have the following beneficial effects: 1. The crushed slurry is added to the inside of the reduction reactor. An appropriate amount of 98% concentrated sulfuric acid and a saturated ferrous sulfate solution are added to the reactor. When the pH of the mixed slurry inside the reduction reactor reaches 4-5, the reaction can proceed. Restore to During the reduction process, 98% concentrated sulfuric acid is added. The resulting acid mist is drawn into the acid mist absorption tower by the anti-corrosion fan. After being neutralized by alkali inside the acid mist absorption tower, it is discharged through the discharge pipe after meeting the emission standards, which increases the safety of the emitted gas. 2. The heavily contaminated soil inside the storage box will be fed into the ball mill by the belt conveyor during operation. The soil inside the ball mill will be processed into slurry to increase the contact area between the soil and the reactants and increase the reaction rate. The heavily contaminated soil that is dug out will be poured onto the inclined screen. The inclined screen with a certain angle will be used to remove impurities and foreign objects from the soil to avoid these impurities interfering with the subsequent reaction. 3. When the ball mill is crushing heavily contaminated soil, the water in the water tank is pumped into the water injection pipe and injected into the ball mill. This allows for the addition of water in a measured amount while crushing the soil, resulting in a particle size of 200 mesh after 98% crushing. This increases the precision of the material during crushing. The slurry produced by the ball mill is discharged into the storage box. When the storage box is full and slides inside the sliding port, the bottom surface of the fixed frame rolls on the rollers, reducing the friction of the storage box during movement. IV. When the slurry reacts inside the reduction reaction tank, the output shaft of the motor will drive the rotating shaft to rotate synchronously, which will drive the stirring plate to stir the slurry inside the reduction reaction tank, so that the slurry and reactants can be in full contact. 5. Reacted or unreacted sulfuric acid will be stored inside the underground sulfuric acid tank and covered with a cover plate to prevent passing workers from falling into the underground sulfuric acid tank, thus increasing the safety of the workers. When the cover plate is on the underground sulfuric acid tank, the fixing column will be inside the limiting port. Then the workers will rotate the limiting plate and use the cross setting of the limiting plate and the limiting port to fix the position of the connecting plate on the ground. Attached Figure Description

[0024] Figure 1 This is a three-dimensional schematic diagram of an embodiment.

[0025] Figure 2 This is an exploded three-dimensional schematic diagram of an embodiment.

[0026] Figure 3 This is an exploded view of the fixing plate and water tank in the embodiment.

[0027] Figure 4 This is an exploded view of the storage box and mounting frame in the embodiment.

[0028] Figure 5 This is an exploded view of the sliding opening and storage box in the embodiment.

[0029] Figure 6 This is an exploded view of the rotating shaft and stirring plate in the embodiment.

[0030] Figure 7 for Figure 5 A magnified schematic diagram of the local structure at point A in the middle.

[0031] In the diagram: 1. Ground; 2. Acid mist absorption tower; 3. Reduction reaction tank; 4. Sealing cover; 5. Connecting pipe; 6. Corrosion-resistant induced draft fan; 7. Storage box; 8. Ball mill; 9. Base; 10. Belt conveyor; 11. Arc plate; 12. Discharge pipe; 13. Supporting folding plate; 14. Positioning plate; 15. Mounting frame; 16. Inclined screen; 17. Support plate; 18. Fixing plate; 19. Water tank; 20. Water pump; 21. Water injection hole; 22. Water injection pipe; 23. Addition hole; 24. Addition pipe; 25. Sliding port; 26. Storage box; 27. Fixing frame; 28. Mounting port; 29. ​​Roller; 30. Motor; 31. Rotating shaft; 32. Stirring plate; 33. Sulfuric acid underground tank; 34. Cover plate; 35. Fixing column; 36. Connecting plate; 37. Limiting port; 38. Rotating column; 39. Limiting plate. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figure 1 and Figure 2 As shown, a remediation device for soil heavy metal pollution remediation includes an acid mist absorption tower 2, which is installed on the top surface of ground 1. Ground 1 is equipped with a purification component, a crushing component, a screening component, a humidification component, a transfer component, a stirring component, and a protection component. The purification component is connected to the reduction reaction tank 3 through the stirring component. The purification components include a detachable sealing cover 4 installed on the top surface of the reduction reaction tank 3. A connecting pipe 5 is fixed to the top surface of the sealing cover 4, and the other end of the connecting pipe 5 is fixed to the top of the acid mist absorption tower 2. Several corrosion-resistant induced draft fans 6 are installed on the acid mist absorption tower 2, and an exhaust pipe 12 is installed through the acid mist absorption tower 2. A crushing component for breaking up soil is installed on the ground 1, a screening component for screening soil is installed on the ground 1, a humidification component for injecting water is installed on the ground 1, a transfer component for storing slurry is installed on the ground 1, a stirring component for stirring slurry is installed inside the reduction reaction tank 3, and a protective component for storing sulfuric acid is installed on the ground 1. Restore to When the acid mist is generated, it will be drawn into the acid mist absorption tower 2 by the anti-corrosion induced draft fan 6. Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower 2. When the gas reaches the emission standard, it will be discharged from the inside of the acid mist absorption tower 2 through the emission pipe 12.

[0034] During use, the crushed slurry is added into the reduction reaction tank 3. An appropriate amount of 98% concentrated sulfuric acid and a saturated ferrous sulfate solution are added to the inside of the reduction reaction tank 3. When the pH value of the mixed slurry inside the reduction reaction tank 3 reaches 4-5, the slurry can be... Restore to During the reduction process, 98% concentrated sulfuric acid is added, and the resulting acid mist is drawn into the acid mist absorption tower 2 by the anti-corrosion fan 6. After being neutralized by alkali inside the acid mist absorption tower 2, it is discharged through the discharge pipe 12 after meeting the emission standards, thus increasing the safety of the emitted gas.

[0035] like Figures 2-4 As shown, the crushing assembly includes a storage box 7 set on the ground 1, two bases 9 set on the ground 1, a ball mill 8 set on the ground 1, the bases 9 and the bottom surface of the ball mill 8 are fixedly installed, a belt conveyor 10 is set inside the storage box 7, several arc plates 11 are fixed on the surface of the belt conveyor 10, two supporting folding plates 13 are fixed on the surface of the ball mill 8, and the belt conveyor 10 is set between the two supporting folding plates 13. The screening assembly includes two positioning plates 14 set on the top surface of the storage box 7, an installation frame 15 is hinged between the two positioning plates 14, an inclined screen 16 is set inside the installation frame 15, two support plates 17 are fixed on the top surface of the storage box 7, and one side of the support plate 17 is fixed to one side of the installation frame 15.

[0036] During use, the heavily contaminated soil inside the storage box 7 is fed into the ball mill 8 by the belt conveyor 10. The soil inside the ball mill 8 is processed into a slurry to increase the contact area between the soil and the reactants and increase the reaction rate. The heavily contaminated soil that is excavated is poured onto the inclined screen 16. The inclined screen 16, which has a certain angle, is used to remove impurities and foreign objects from the soil to prevent these impurities from interfering with the subsequent reaction.

[0037] like Figure 3 and Figure 5 As shown, the humidification assembly includes two fixed plates 18 mounted on the ball mill 8. A water tank 19 is mounted on the ball mill 8. A water pump 20 is mounted on the bottom surface of the water tank 19. A water inlet pipe 22 is fixed to the drain pipe of the water pump 20. A water inlet hole 21 is opened on the surface of the ball mill 8. The bottom end of the water inlet pipe 22 passes through the bottom surface of the water tank 19 and extends into the interior of the ball mill 8 through the water inlet hole 21. An addition hole 23 is opened on the top surface of the water tank 19. An addition pipe 24 is fixed on the top surface of the water tank 19. The central axis of the addition hole 23 and the addition pipe 24 are aligned. The transfer assembly includes a sliding port 25 opened on the ground 1. A storage box 26 is slidably mounted inside the sliding port 25. A fixed frame 27 is fixed on the top surface of the storage box 26. Several installation ports 28 are opened on the ground 1. Rollers 29 are rotatably mounted inside the installation ports 28.

[0038] During use, when the ball mill 8 is crushing heavily polluted soil, the water in the water tank 19 is pumped into the water injection pipe 22 by the water pump 20 and injected into the ball mill 8. This allows for the addition of water in a measured amount while crushing the soil, resulting in a particle size of 200 mesh after 95% crushing, which increases the precision of the material during crushing. The slurry produced by the ball mill 8 is discharged into the storage box 26. When the storage box 26 is full and slides inside the sliding port 25, the bottom surface of the fixed frame 27 rolls on the roller 29, reducing the friction of the storage box 26 during movement.

[0039] like Figure 6 As shown, the stirring assembly includes a motor 30 disposed on the bottom surface of the reduction reaction vessel 3. The output shaft of the motor 30 is rotatably inserted into the bottom surface of the reduction reaction vessel 3. A rotating shaft 31 is fixed on the output shaft of the motor 30, and several stirring plates 32 are fixed on the surface of the rotating shaft 31.

[0040] During use, when the slurry reacts inside the reduction reaction tank 3, the output shaft of the motor 30 will drive the rotating shaft 31 to rotate synchronously, which will drive the stirring plate 32 to stir the slurry inside the reduction reaction tank 3, so that the slurry and reactants can be in full contact.

[0041] like Figure 2 , Figure 5 and Figure 7 As shown, the protective assembly includes a sulfuric acid underground tank 33 installed on the ground 1. A cover plate 34 is rotatably installed on the ground 1 via a hinge. The protective assembly also includes two fixed posts 35 fixed on the ground 1. A connecting plate 36 is fixed to one side of the cover plate 34. A limit opening 37 is opened on one side of the connecting plate 36. A rotating post 38 is fixed to the top of the fixed post 35. A limit plate 39 is rotatably sleeved on the rotating post 38.

[0042] During use, sulfuric acid, whether reacted or unreacted, is stored inside the sulfuric acid underground tank 33, and a cover plate 34 is used to cover the sulfuric acid underground tank 33 to prevent passing workers from falling into the sulfuric acid underground tank 33, thus increasing the safety of the workers. When the cover plate 34 is fastened on the sulfuric acid underground tank 33, the fixing post 35 will be inside the limiting port 37. Then, the worker rotates the limiting plate 39, and the connecting plate 36 is fixed at the position of the ground 1 by using the cross arrangement of the limiting plate 39 and the limiting port 37.

[0043] This invention also provides a remediation method for a soil heavy metal pollution remediation device, the specific steps of which are as follows: Step 1: The heavily contaminated soil that was excavated ( Soil containing ≥2000mg / kg and total chromium ≥10000mg / kg is poured onto an inclined screen 16. After being screened by the inclined screen 16 to remove impurities, the screened soil falls into the storage box 7 and is then conveyed by the belt conveyor 10 into the ball mill 8. The ball mill 8 is used to crush the soil. At the same time, the water pump 20 injects water from the water tank 19 into the ball mill 8. The particle size of the soil or chromium slag entering the ball mill 8 must be ≤10mm, and it must be free of impurities such as bricks, stones, cement, and plastics. The amount of slag entering the ball mill 8 is 10-20t / h, and the amount of water entering the ball mill 8 is 15-30t / h. The solid-liquid content of the slurry discharged from the ball mill 8 is 30%-60%. Step 2: The heavily contaminated soil, after being ground by ball mill 8, will be made into a slurry. This slurry will then be added to the reduction reaction tank 3. A suitable amount of 98% concentrated sulfuric acid and ferrous sulfate saturated solution will be added to the reduction reaction tank 3 at a mass ratio of 0.2:1. The pH value will be monitored; when the pH of the mixed slurry reaches 4-5, the reduction reaction will reach its endpoint. The dissolved... Fully restored to The entire reduction reaction takes no less than 8 hours, and the final leachate contains... The concentrations of pollutants must be ≤3 mg / L, total chromium ≤9 mg / L, and Ni ≤50 mg / L. The pH must be within the range of 6-9. The test results of the detoxified products must simultaneously meet the following requirements: the exceedance rate of the samples must not exceed 20%, and the arithmetic mean of the exceedance sample test results must not exceed 120% of the control index limit. This must comply with the "Pollution Control Standard for General Industrial Solid Waste Storage and Disposal Sites." After sampling and testing the reduced slurry, ensuring… After passing the inspection, proceed to the next stage of the process; Step 3, ensuring After passing the test, the generated acid mist will be drawn into the acid mist absorption tower 2 by the anti-corrosion induced draft fan 6. Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower 2. When the gas reaches the emission standard, it will be discharged from the inside of the acid mist absorption tower 2 through the emission pipe 12. At this time, the pH of the slurry is 6~9. Step 4: After taking out 98% concentrated sulfuric acid from the underground sulfuric acid tank 33, the staff will put the cover plate 34 on the underground sulfuric acid tank 33, drive the fixing column 35 to be inserted into the limit port 37, and use the limit plate 39 that crosses on the limit port 37 to fix the connecting plate 36 to the ground. Step 5: The mixed slurry completed in the reduction stage will be added to the neutralization reaction tank, and slaked lime milk for neutralization reaction will be added to the neutralization reaction tank. After thorough stirring, the pH of the slurry in the neutralization reaction tank will be adjusted to about 6-7, which is the end point of the neutralization reaction. The pH will be kept constant for half an hour while stirring. The entire neutralization reaction time will be no less than 1 hour. Then the neutralized slurry will be discharged and solid-liquid separation will be carried out through a high-pressure diaphragm plate and frame filter press. Step 6: Use a slurry pump to pump the slurry to the high-pressure diaphragm plate and frame filter press in the dewatering workshop for solid-liquid separation. The resulting filter cake has a moisture content of about 50%, and is then transferred to the inspection plant for temporary storage. Step 7: The wastewater after solid-liquid separation will be injected into the sedimentation pipe. At the same time, the chromium slag to be tested in the wastewater will be settled by static sedimentation. After preliminary sedimentation, the supernatant will be pumped out by the metering pump and reused in the ball mill 8 and the reduction reaction tank 3.

[0044] Working principle: Heavily polluted soil is first screened by an inclined screen 16 to remove impurities. The screened soil falls into a storage box 7 and is then conveyed to a ball mill 8 by a belt conveyor 10. While the ball mill 8 is crushing the soil, a water pump 20 injects water from a water tank 19 through a water injection pipe 22, forming a slurry with a particle size of 200 mesh, improving the efficiency of subsequent reactions. After the slurry enters the reduction reaction tank 3, a saturated solution of 98% concentrated sulfuric acid and ferrous sulfate is added. The slurry is mixed with a stirring plate 32 by a motor 30 driving a rotating shaft 31, maintaining the pH value within the range of 4-5, promoting… Restore to The acid mist generated during the reaction is drawn into the acid mist absorption tower 2 by the corrosion-resistant induced draft fan 6. After being neutralized by alkali, the qualified gas is discharged through the discharge pipe 12 to avoid environmental pollution.

[0045] Sulfuric acid is stored in an underground sulfuric acid tank 33. The cover 34 is locked to the fixed column 35 by a limiting plate 39 to prevent accidental contact by personnel. After ball milling, the slurry is temporarily stored in a storage box 26, and rollers 29 reduce the friction during transfer.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A remediation device for soil heavy metal pollution remediation, comprising an acid mist absorption tower (2), wherein the acid mist absorption tower (2) is disposed on the top surface of the ground (1), characterized in that, The ground (1) is equipped with a purification component, a crushing component, a screening component, a humidification component, a transfer component, a stirring component and a protective component. The purification component is connected to the reduction reaction tank (3) through the stirring component. The purification assembly includes a detachable sealing cover (4) installed on the top surface of the reduction reaction tank (3). A connecting pipe (5) is fixed to the top surface of the sealing cover (4). The other end of the connecting pipe (5) is fixed to the top of the acid mist absorption tower (2). Several anti-corrosion induced draft fans (6) are installed on the acid mist absorption tower (2). An exhaust pipe (12) is installed through the acid mist absorption tower (2). A crushing assembly for crushing soil is installed on the ground (1). A screening assembly for screening soil is installed on the ground (1). A humidifying assembly for injecting water is installed on the ground (1). A transfer assembly for storing slurry is installed on the ground (1). A stirring assembly for stirring slurry is installed inside the reduction reaction tank (3). A protective assembly for storing sulfuric acid is installed on the ground (1). Restore to When the acid mist is generated, it will be drawn into the interior of the acid mist absorption tower (2) by the anti-corrosion induced draft fan (6). Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower (2). When the gas reaches the emission standard, it will be discharged from the interior of the acid mist absorption tower (2) through the emission pipe (12).

2. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The crushing assembly includes a storage box (7) set on the ground (1), two bases (9) are set on the ground (1), a ball mill (8) is set on the ground (1), the bases (9) are fixedly installed on the bottom surface of the ball mill (8), a belt conveyor (10) is set inside the storage box (7), a number of arc plates (11) are fixed on the surface of the belt conveyor (10), two supporting folding plates (13) are fixed on the surface of the ball mill (8), and the belt conveyor (10) is set between the two supporting folding plates (13).

3. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The screening assembly includes two positioning plates (14) disposed on the top surface of the storage box (7), and an installation frame (15) is hinged between the two positioning plates (14). An inclined screen (16) is disposed inside the installation frame (15). Two support plates (17) are fixed on the top surface of the storage box (7), and one side of the support plate (17) is fixed to one side of the installation frame (15).

4. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The humidification assembly includes two fixed plates (18) on the ball mill (8). A water tank (19) is provided on the ball mill (8). A water pump (20) is provided on the bottom surface of the water tank (19). A water injection pipe (22) is fixed to the drain pipe of the water pump (20). A water injection hole (21) is provided on the surface of the ball mill (8). The bottom end of the water injection pipe (22) passes through the bottom surface of the water tank (19) and extends into the interior of the ball mill (8) through the water injection hole (21). An addition hole (23) is provided on the top surface of the water tank (19). An addition pipe (24) is fixed on the top surface of the water tank (19). The central axis of the addition hole (23) and the addition pipe (24) are on the same straight line.

5. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The transfer assembly includes a sliding opening (25) on the ground (1), a storage box (26) is slidably arranged inside the sliding opening (25), a fixing frame (27) is fixed on the top surface of the storage box (26), and a number of installation openings (28) are provided on the ground (1), and rollers (29) are rotatably arranged inside the installation openings (28).

6. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The stirring assembly includes a motor (30) installed on the bottom surface of the reduction reaction tank (3). The output shaft of the motor (30) is rotatably inserted into the bottom surface of the reduction reaction tank (3). A rotating shaft (31) is fixed on the output shaft of the motor (30), and several stirring plates (32) are fixed on the surface of the rotating shaft (31).

7. The remediation device for soil heavy metal pollution remediation according to claim 1, characterized in that: The protective assembly includes an underground sulfuric acid tank (33) set on the ground (1), and a cover plate (34) is provided on the ground (1) by means of a hinge.

8. The remediation device for soil heavy metal pollution remediation according to claim 7, characterized in that: The protective assembly also includes two fixed posts (35) fixed on the ground (1), a connecting plate (36) fixed on one side of the cover plate (34), a limit opening (37) opened on one side of the connecting plate (36), a rotating post (38) fixed at the top of the fixed post (35), and a limit plate (39) rotatably sleeved on the rotating post (38).

9. A remediation method for a soil heavy metal pollution remediation device according to any one of claims 1-8, characterized in that, The specific steps are as follows: Step 1: The heavily contaminated soil that was excavated ( ≥2000mg / kg, total chromium ≥10000mg / kg) are poured onto the inclined screen (16). After the inclined screen (16) removes impurities from the soil, the soil will fall into the storage box (7) and be conveyed by the belt conveyor (10) into the ball mill (8). The ball mill (8) is used to crush the soil. At the same time, the water pump (20) will inject water from the water tank (19) into the ball mill (8). The particle size of the soil or chromium slag entering the ball mill (8) is required to be ≤10mm, and it is required to be free of bricks, stones, cement, plastics and other impurities. The amount of slag entering the ball mill (8) is 10-20t / h, the amount of water entering the ball mill (8) is 15-30t / h, and the solid-liquid content of the slurry discharged from the ball mill (8) is 30%-60%. Step 2: The heavily contaminated soil, after being ground by a ball mill (8), will be made into a slurry. The slurry will then be added into the reduction reaction tank (3). A suitable amount of 98% concentrated sulfuric acid and ferrous sulfate saturated solution will be added to the reduction reaction tank (3) at a mass ratio of 0.2:

1. By detecting the pH value, when the pH of the mixed slurry reaches 4~5, the reduction reaction endpoint is reached. The dissolved... Fully restored to The entire reduction reaction takes no less than 8 hours, and the final leachate contains... ≤3mg / L, total chromium ≤9mg / L, and Ni ≤50mg / L, while pH is within the range of 6~9. After sampling and testing the reduced slurry, it was ensured that... After passing the inspection, proceed to the next stage of the process; Step 3, ensuring After passing the test, the generated acid mist will be drawn into the interior of the acid mist absorption tower (2) by the anti-corrosion induced draft fan (6). Then, the acid mist will be neutralized by alkali inside the acid mist absorption tower (2). When the gas reaches the emission standard, it will be discharged from the interior of the acid mist absorption tower (2) through the discharge pipe (12). At this time, the pH of the slurry is 6~9. Step 4: After taking out 98% concentrated sulfuric acid from the underground sulfuric acid tank (33), the staff will put the cover plate (34) on the underground sulfuric acid tank (33), drive the fixing column (35) to be inserted into the limit port (37), and use the limit plate (39) that crosses on the limit port (37) to fix the connecting plate (36) on the ground (1); Step 4: After taking out 98% concentrated sulfuric acid from the underground sulfuric acid tank (33), the staff will put the cover plate (34) on the underground sulfuric acid tank (33), drive the fixing column (35) to be inserted into the limit port (37), and use the limit plate (39) that crosses on the limit port (37) to fix the connecting plate (36) on the ground. Step 5: The mixed slurry completed in the reduction stage will be added to the neutralization reaction tank, and slaked lime milk for neutralization reaction will be added to the neutralization reaction tank. After thorough stirring, the pH of the slurry in the neutralization reaction tank will be adjusted to about 6-7, which is the end point of the neutralization reaction. The pH will be kept constant for half an hour while stirring. The entire neutralization reaction time will be no less than 1 hour. Then the neutralized slurry will be discharged and solid-liquid separation will be carried out through a high-pressure diaphragm plate and frame filter press. Step 6: Use a slurry pump to pump the slurry to the high-pressure diaphragm plate and frame filter press in the dewatering workshop for solid-liquid separation. The resulting filter cake has a moisture content of about 50%, and is then transferred to the inspection plant for temporary storage. Step 7: The wastewater after solid-liquid separation will be injected into the sedimentation pipe. At the same time, the chromium slag to be tested in the wastewater will be settled by static sedimentation. After preliminary sedimentation, the upper clear liquid will be extracted by metering pump and reused in the ball mill (8) and reduction reaction tank (3).

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