A soil pollution pretreatment apparatus and a pretreatment method thereof

Abstract

The application discloses a kind of contaminated soil pretreatment equipment and its pretreatment method, including screening device, conveying device and winnowing device, the screening device will be broken to dry soil screening, screen out the soil particles with particle size below 2mm, and these small particle soil is conveyed to conveying device, conveying device conveys soil particles to winnowing device, winnowing device will be winded to soil particles, and heavy soil is separated from light soil in soil particles, the winnowing device includes discharge bin and winnowing box, the top of the discharge bin is provided with feed inlet.The application separates soil particles into light and heavy soil particles according to density difference, and judges whether it reaches direct reuse standard by sampling detection of light soil particles, realizes the quality of soil components after winnowing and differentiates processing according to flow.

Description

Technical Field

[0001] This invention relates to the field of environmental protection equipment technology, and in particular to a contaminated soil pretreatment device and its pretreatment method. Background Technology

[0002] In the process of contaminated soil remediation, the soil usually needs to be pretreated, including crushing, screening and conveying, in order to improve the physical properties of the soil and provide suitable feeding conditions for subsequent remediation processes.

[0003] In existing technologies, some contaminated soil pretreatment equipment uses wind-powered screening devices to separate light and heavy components in soil. However, this approach primarily removes light dust from soil particles and cannot effectively classify the soil particles themselves according to density. This makes it difficult to selectively separate soils with different levels of contamination and to achieve precise subsequent treatment. Furthermore, sampling with existing equipment typically requires stopping the machine or manual removal from the discharge port, making online sampling difficult, inconvenient, and resulting in insufficient representativeness of the test results.

[0004] Therefore, how to provide a pretreatment device and method for contaminated soil is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] One objective of this invention is to provide a pretreatment device and method for contaminated soil. This invention separates soil particles into light and heavy soil particles according to their density differences, and determines whether the light soil particles meet the standards for direct reuse by sampling and testing them, thereby realizing the separation and differentiated treatment of soil components according to their quality after air separation.

[0006] According to an embodiment of the present invention, a contaminated soil pretreatment device includes a screening device, a conveying device, and an air separation device. The screening device crushes and screens dry soil to separate soil particles with a particle size of less than 2 mm, and conveys these small soil particles to the conveying device. The conveying device conveys the soil particles to the air separation device, which separates the light soil particles from the heavy soil particles. The air separation device includes a feeding box and an air separation box. The top of the feeding box has an inlet, through which soil particles conveyed by the conveying device directly enter the feeding box. Inside the feeding box, multiple inclined feeding plates are continuously fixed from top to bottom and span the entire cross-section. When soil particles pass through the inlet... After entering the feeding box, the particles fall directly onto the feeding plate and move along the inclined direction of the feeding plate. A partition is fixed between the feeding box and the air classifier. The partition has blowing holes, and nozzles adapted to the blowing holes are fixed inside the blowing holes. The nozzles are connected to an external fan or air pump through pipelines. The nozzles are fixed to the feeding plate. When the dust particles on the feeding plate move to the nozzles, the nozzles spray high-speed airflow, thereby causing the dust particles at the nozzles to be lifted. Due to the different densities of light and heavy soil particles, heavy soil particles settle faster and have a shorter horizontal displacement in the airflow, falling into the near-end area of ​​the air classifier. Light soil particles settle slower and have a longer horizontal displacement, and are carried by the airflow to the far-end area of ​​the air classifier, thereby achieving the separation of light and heavy soil particles.

[0007] The bottom of the air classifier is provided with two collection hoppers, and a triangular wedge is fixed between the two collection hoppers. The two collection hoppers are located on the left and right sides of the triangular wedge, respectively. The cross-section of the triangular wedge is triangular, and its tip is facing upwards and directly opposite the material drop area of ​​the air classifier. The triangular wedge is used to guide and divert the falling heavy and light soil particles along its two inclined surfaces, so that the material falls evenly into the left and right collection hoppers.

[0008] Preferably, each of the collection hoppers is provided with two sampling components. Each sampling component includes an outer tube and a sampling tube. The outer tube is fixedly installed on the wall of the collection hopper, with a portion extending into the hopper. The sampling tube is rotatably and sealingly connected to the inside of the outer tube and can rotate bidirectionally (clockwise or counterclockwise) relative to the outer tube. An elongated feed inlet is provided on the upward-sloping side of the outer tube. A spiral groove is provided on the sampling tube, with fewer than one turn and a length equal to the length of the feed inlet. Simultaneously, the portion of the sampling tube without the spiral groove can completely block the feed inlet. When sampling is required... During sampling, the operator rotates the sampling tube so that the spiral groove on the sampling tube gradually faces and connects to the feed orifice of the outer tube. As the sampling tube rotates continuously, the overlapping position of the spiral groove and the feed orifice gradually moves along the length of the feed orifice. Soil particles in the collection hopper fall into the spiral groove along the feed orifice and continuously enter the interior of the sampling tube along the spiral path, realizing continuous spatial sampling at different positions along the length of the feed orifice. After sampling is completed, the sampling tube is rotated to the closed position so that the outer wall of the sampling tube without the spiral groove blocks the feed orifice, preventing material from continuously entering the interior of the sampling tube during non-sampling periods.

[0009] Preferably, the two sampling components in the same hopper are inserted obliquely upward from the left side wall of the hopper and extend to the right side inside the hopper. The projections of the two sampling components in the horizontal direction and in the vertical direction are both in a state of left-low and right-high, and the distance between them gradually increases from left to right. The overall arrangement is approximately V-shaped, but the near ends do not contact each other.

[0010] Preferably, the outer tube is rotatably mounted on the wall of the collection hopper. Multiple protrusions are fixedly installed on the outer wall of the section of the outer tube inside the collection hopper. The outer tube can rotate in a certain direction (e.g., clockwise). As the outer tube rotates, the protrusions disturb and loosen the soil particles deposited in the collection hopper, preventing soil particles from settling and compacting at the bottom of the hopper. This keeps the soil at the sampling component in a loose state, facilitating the smooth entry of soil particles into the sampling port. The sampling tube is rotatably and sealingly connected inside the outer tube and rotates in the opposite direction. When sampling is required, the sampling tube rotates to collect the sample without causing the outer tube to rotate. The rotation of the outer tube and the sampling rotation of the sampling tube are independent of each other; they can be performed simultaneously or controlled separately. The protrusions on the outer tube disturb the material, ensuring it remains in a loose and flowable state, creating favorable conditions for sampling. The sampling tube rotates as needed to open and close the sampling port.

[0011] Furthermore, a first hexagonal block is fixed to the end of the outer tube, and a second hexagonal block is fixed to the portion of the sampling tube extending out of the outer tube. The arrangement of the first and second hexagonal blocks facilitates the use of tools to rotate the outer tube and the sampling tube. The same screw is also threaded onto the first and second hexagonal blocks.

[0012] Preferably, among the multiple feeding plates, except for the bottom one which is a complete plate, the other feeding plates are provided with multiple equidistant material dispersing holes, and the material dispersing holes on each feeding plate are staggered in the vertical direction. The blowing holes are narrow holes, and the length of the nozzle is equal to the length of the blowing hole.

[0013] Preferably, the nozzle has a trapezoidal structure, with one of its inclined surfaces having the same inclination as the feed plate, and this inclined surface is continuous with the corresponding feed plate. This ensures a smooth transition of soil particles as they move along the surface of the feed plate to the nozzle, preventing particle accumulation due to abrupt structural changes. The nozzle has an internal cavity to accommodate airflow from an external air source. A long, flat, elongated air outlet is located on the side of the nozzle closest to the air separator, communicating with the cavity. The air outlet gradually narrows from the inside out, flattening the cross-section of the airflow channel, thereby compressing the airflow and increasing its velocity, thus improving the ability to disperse soil particles. Simultaneously, the air outlet is angled upwards, causing the ejected airflow to be directed obliquely upwards, lifting the soil particles moving to the nozzle obliquely upwards. This gives the soil particles an initial upward velocity upon entering the air separator, prolonging their time in the airflow and improving the air separation effect.

[0014] Preferably, guide plates are fixed on both sides of the feeding plate. The two guide plates tighten sequentially along the inclined direction of the feeding plate, gathering the soil particles on the feeding plate towards the center. The distance between the closest ends of the two guide plates is equal to the distance between the farthest sections of the two sampling components in the same collection hopper, so that the gathered soil particles can fall as far as possible into the sampling area of ​​the sampling component.

[0015] A method for pretreatment of contaminated soil includes the following steps: S1: The dry soil is fed into the screening device for crushing and screening, and soil particles with a diameter of less than 2mm are screened out. S2: The soil particles screened in S1 are conveyed to the feeding box by the conveying device. The soil particles fall into the multi-layer feeding plate in the feeding box through the inlet and move downward along the surface of the feeding plate. Some of the soil particles pass through the dispersing holes and fall to the next layer of the feeding plate. The soil particles that do not pass through the dispersing holes continue to move along the plate surface to the nozzle. The dispersing holes on each layer of the feeding plate are arranged in a staggered manner in the vertical direction, so that the soil particles are dispersed multiple times during the falling process and avoid concentrated falling. S3: The nozzle sprays a high-speed airflow, which blows away the soil particles that have moved to the nozzle and lifts them obliquely upward, so that the soil particles enter the air classifier evenly and loosely. S4: Soil particles entering the air classifier are separated according to density differences under the action of airflow. Heavy soil particles settle faster and have a shorter horizontal displacement, falling into the near end area of ​​the air classifier, while light soil particles settle slower and have a longer horizontal displacement, being carried by the airflow to the far end area of ​​the air classifier, thus achieving the separation of light and heavy soil particles. S5: After separation, the heavy soil particles are guided by a triangular wedge to fall into the left collection hopper, and the light soil particles are guided by a triangular wedge to fall into the right collection hopper. S6: Samples are taken from each collection hopper by the sampling component. The sampling tube is rotated so that the spiral groove gradually connects with the feed hole of the outer tube. Spatial continuous sampling is carried out at different positions along the length of the feed hole, and the extracted lightweight soil particles are tested. S7: Based on the test results of S6, if the pollutant content of the lightweight soil particles meets the standard, it can be reused directly; if it does not meet the standard, the dosage of the agent will be determined based on the test results, and subsequent remediation treatment will proceed.

[0016] The beneficial effects of this invention are: 1. This invention separates soil particles into light and heavy soil particles according to density differences using an air separation device. By sampling and testing the light soil particles, it determines whether they meet the standards for direct reuse. This achieves the separation and differentiated treatment of soil components according to quality after air separation, avoiding the waste and increased costs caused by uniform dosing, and realizing the precise addition of chemicals.

[0017] 2. The sampling component set on the hopper in this invention gradually connects the spiral groove with the feed orifice by rotating the sampling tube. It can continuously collect soil samples from different locations along the length of the feed orifice, covering different heights and accumulation slopes in the hopper, avoiding detection deviations caused by fixed-point sampling. The sampling process does not require stopping the machine and does not interfere with the normal operation of the air classifier, making it convenient to operate.

[0018] 3. In this invention, a protrusion is provided on the outer wall of the pipe section located inside the collection hopper. By rotating the outer pipe, the protrusion disturbs and loosens the deposited soil particles, preventing material from being deposited and compacted. This ensures that the soil at the sampling component is always in a loose and flowable state, ensuring smooth and continuous sampling. At the same time, the flowability of the loosened soil particles is improved, which is conducive to the smooth discharge of materials in the collection hopper and avoids the problem of poor discharge caused by material bridging or compaction.

[0019] 4. This invention uses a first hexagonal block and a second hexagonal block in conjunction with a screw locking component to easily fix the outer tube and the sampling tube together when not sampling. This allows the outer wall of the sampling tube without the spiral groove to block the feed hole, preventing material from entering the sampling tube during non-sampling periods. The screw also has a positioning marking function, making it easy for operators to accurately determine the orientation of the sampling port. The structure is simple and the operation is intuitive.

[0020] 5. The present invention sets up multiple layers of feeding plates with staggered material dispersing holes in the feeding box, so that the soil particles are dispersed multiple times during the falling process, avoiding concentrated falling, and ensuring that the soil particles are evenly distributed in the vertical direction before entering the air separation box, which effectively improves the subsequent air separation effect.

[0021] 6. The present invention designs the nozzle as a trapezoidal structure, with its inclined surface continuously transitioning to the feed plate to prevent particle accumulation. The air outlet gradually narrows from the inside to the outside to compress the airflow and increase the flow rate. Furthermore, the upward tilting setting causes the soil particles to be lifted obliquely upward, prolonging their action time in the airflow in the air separator and further improving the separation accuracy of light and heavy particles.

[0022] 7. The present invention provides guide plates that tighten sequentially along the inclined direction on both sides of the feeding plate, which gathers soil particles toward the center, so that the feeding area corresponds as much as possible with the sampling area of ​​the sampling component, so that the sampling component can collect more representative samples. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a contaminated soil pretreatment device proposed in this invention; Figure 2 This is a cross-sectional structural diagram of the air separation device in a contaminated soil pretreatment equipment proposed in this invention.

[0024] Figure 3 This is a cross-sectional view of the feeding box in a contaminated soil pretreatment device proposed in this invention.

[0025] Figure 4 This is a cross-sectional structural diagram of the feeding plate and nozzle in a contaminated soil pretreatment device proposed in this invention.

[0026] Figure 5 This is a side sectional view of the feed plate and nozzle in a contaminated soil pretreatment device proposed in this invention.

[0027] Figure 6 This is a schematic diagram of the assembly of the feeding plate and the guide plate in a contaminated soil pretreatment device proposed in this invention.

[0028] Figure 7 This is a schematic diagram of the assembly of the collection trough, triangular wedge, and sampling components in a contaminated soil pretreatment device proposed in this invention.

[0029] Figure 8 This is a top view schematic diagram of the material collection trough, triangular wedge, and sampling component in a contaminated soil pretreatment device proposed in this invention.

[0030] Figure 9 This is a schematic diagram of the sampling component in a contaminated soil pretreatment device proposed in this invention.

[0031] Figure 10This is a schematic diagram of the outer tube of the sampling component in a contaminated soil pretreatment device proposed in this invention.

[0032] Figure 11 This is a schematic diagram of the sampling tube in a sampling component of a contaminated soil pretreatment device proposed in this invention.

[0033] In the diagram: 1. Screening device; 2. Conveying device; 3. Air separator; 4. Feeding box; 5. Air separator box; 6. Feeding plate; 7. Baffle plate; 8. Blowing hole; 9. Nozzle; 91. Cavity; 92. Air outlet; 10. Dispersion hole; 11. Guide plate; 12. Collecting hopper; 13. Triangular wedge; 14. Sampling assembly; 15. Outer tube; 16. Sampling tube; 17. Feed elongated hole; 18. Spiral groove; 19. First hexagonal block; 20. Second hexagonal block; 21. Screw; 22. Protrusion. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0035] Example 1 refer to Figure 1-11 The contaminated soil pretreatment equipment includes a screening device 1, a conveying device 2, and an air separation device 3. The screening device 1 crushes and screens the dry soil, separating soil particles with a diameter of less than 2 mm. These small soil particles are then conveyed to the conveying device 2, which in turn conveys them to the air separation device 3. The air separation device 3 separates the soil particles into light and heavy soil particles. Heavy soil particles refer to those containing heavy metal pollutants and having a higher density, while light soil particles refer to those containing little or no heavy metals. Under the action of airflow separation, pollutants and low-density soil particles are separated. Heavy soil particles settle at the near end of the air separation box, while light soil particles are carried to the far end by the airflow. This allows for the separate collection of light and heavy soil particles after air separation. The light soil particles are then tested to determine if they meet the standards for direct reuse, while the heavy soil particles undergo further remediation treatment. Furthermore, the pollutant content of the light and heavy soil particles after air separation differs, allowing for the application of different dosages of remediation agents, thus achieving precise dosing and rational use of the agents.

[0036] The air classifier 3 includes a feeding box 4 and an air classifier box 5. The top of the feeding box 4 has an inlet. Soil particles conveyed by the conveying device 2 enter the feeding box 4 directly through the inlet. Inside the feeding box 4, multiple inclined feeding plates 6 are continuously fixed from top to bottom and span the entire cross-section. When soil particles enter the feeding box 4 through the inlet, they fall directly onto the feeding plates 6 and move along the inclined direction of the feeding plates 6. A partition 7 is fixed between the feeding box 4 and the air classifier box 5. The partition 7 has blowing holes 8, and a device for blowing dust is fixed inside the blowing holes 8. The nozzle 9 is adapted to the hole 8. The nozzle 9 is connected to an external fan or air pump through a pipeline. The nozzle 9 is fixed to the feed plate 6. When the dust particles on the feed plate 6 move to the nozzle 9, the nozzle 9 sprays out a high-speed airflow, which drives the dust particles at the nozzle 9 to rise. Due to the different densities of light and heavy soil particles, the heavy soil particles settle faster and have a shorter horizontal displacement in the airflow, falling into the near-end area of ​​the air classifier 5; the light soil particles settle slower and have a longer horizontal displacement, and are carried by the airflow to the far-end area of ​​the air classifier 5, thereby achieving the separation of light and heavy soil particles.

[0037] Two collection hoppers 12 are provided at the bottom of the air classifier 5. A triangular wedge 13 is fixed between the two collection hoppers 12. The two collection hoppers 12 are located on the left and right sides of the triangular wedge 13, respectively. The cross-section of the triangular wedge 13 is triangular, with its tip pointing upwards and facing the material drop area of ​​the air classifier 5. The triangular wedge 13 is used to guide and divert the falling heavy and light soil particles along its two inclined surfaces, so that the material falls evenly into the two collection hoppers 12.

[0038] Each collection hopper 12 is equipped with two sampling components 14. These components are used to sample soil particles so that personnel can test and determine the pollutant content in the lightweight particles, thereby determining whether the lightweight soil can be used directly or requires further treatment. Even if further treatment is required, this test can determine the dosage of chemicals used, thus achieving the goal of rational chemical use. Each sampling component 14 includes an outer tube 15 and a sampling tube 16. The outer tube 15 is fixedly installed on the wall of the collection hopper 12, with a portion extending into the hopper 12. The sampling tube 16 is rotatably and sealed to the inside of the outer tube 15 and can rotate bidirectionally (clockwise or counterclockwise) relative to the outer tube 15. An elongated feed hole 17 is provided on the upward-sloping side of the outer tube 15. A spiral groove 18 is provided on the sampling tube 16, with fewer than one turn and a length equal to the feed hole length. The length of the inlet hole 17 is such that the portion of the sampling tube 16 without the spiral groove 18 can completely block the feed hole 17. When sampling is required, the operator rotates the sampling tube 16 so that the spiral groove 18 on the sampling tube 16 gradually faces and connects to the feed hole 17 of the outer tube 15. As the sampling tube 16 rotates continuously, the overlapping position of the spiral groove 18 and the feed hole 17 gradually moves along the length of the feed hole 17. Soil particles in the collection hopper 12 fall into the spiral groove 18 along the feed hole 17 and continuously enter the interior of the sampling tube 16 along the spiral path, realizing continuous spatial sampling at different positions along the length of the feed hole 17. After sampling is completed, the sampling tube 16 is rotated to the closed position so that the outer wall portion of the sampling tube 16 without the spiral groove 18 blocks the feed hole 17, preventing materials from continuously entering the interior of the sampling tube 16 during non-sampling periods.

[0039] In this implementation scheme, sampling of soil particles facilitates personnel's determination of whether lightweight soil can be directly reused. In cases where reuse is not possible, the amount of reagent required for lightweight soil particles can be determined more accurately, which differs from the uniform reagent addition method in existing technologies and saves reagent usage. At the same time, the sampling component 14 can directly take samples from the collection hopper 12 without interfering with the normal operation of the air classifier 3, and the collected samples cover different height positions within the collection hopper 12, avoiding detection deviations caused by fixed-point sampling and improving the representativeness of the detection results.

[0040] Example 2 refer to Figure 7-8 The two sampling components 14 in the same hopper 12 are inserted obliquely upward from the left side wall of the hopper 12 and extend to the right side inside the hopper 12. The projections of the two sampling components 14 in the horizontal direction and in the vertical direction are both in a state of left-low and right-high, and the distance between them gradually increases from left to right. The overall arrangement is approximately V-shaped, but the near ends do not contact each other.

[0041] Because the airflow from left to right is blown by the air classifier, heavy soil particles settle in the left collection hopper 12, while light soil particles are carried by the airflow to the right collection hopper 12. Due to the rightward thrust of the airflow, the materials in both collection hoppers 12 are piled up with a lower elevation on the left and a higher elevation on the right. The insertion direction of the two sampling components 14 is approximately the same as the direction of the slope of the material accumulation in their respective collection hoppers 12, so that soil particles can be collected at different heights along the slope of the material accumulation during sampling, ensuring the representativeness of the samples.

[0042] Example 3 refer to Figure 9-11 In this embodiment, the outer tube 15 is rotatably installed on the wall of the collection hopper 12. Multiple protrusions 22 are fixedly provided on the outer wall of the pipe section of the outer tube 15 located in the collection hopper 12. The outer tube 15 can rotate in a certain direction (such as clockwise). When the protrusions 22 rotate with the outer tube 15, they disturb and loosen the soil particles deposited in the collection hopper 12, preventing the soil particles from being deposited and compacted at the bottom of the collection hopper 12, thereby making the soil at the sampling component 14 in a loose state, which is conducive to the soil particles entering the sampling port smoothly.

[0043] The sampling tube 16 is rotatably and sealed inside the outer tube 15 and rotates in the opposite direction. When sampling is required, the sampling tube 16 rotates to take a sample without causing the outer tube 15 to rotate.

[0044] The rotation of the outer tube 15 and the sampling rotation of the sampling tube 16 are independent of each other. They can be carried out simultaneously or controlled separately. The protrusions 22 on the outer tube 15 disturb the material to ensure that the material is in a loose and flowable state, creating favorable conditions for sampling. The sampling tube 16 rotates as needed to open and close the sampling port.

[0045] In addition, the continuous disturbance of the material in the hopper 12 by the protrusion 22 not only creates loose conditions for sampling, but also helps to improve the discharge flow at the bottom of the hopper 12, prevent the material from bridging or compacting due to long-term sedimentation, and ensure smooth discharge.

[0046] In this embodiment, both the outer tube 15 and the sampling tube 16 can be made of one-way bearings to achieve unidirectional rotation and reverse locking.

[0047] Furthermore, a first hexagonal block 19 is fixed to the end of the outer tube 15, and a second hexagonal block 20 is fixed to the portion of the sampling tube 16 extending beyond the outer tube 15. The arrangement of the first hexagonal block 19 and the second hexagonal block 20 facilitates the use of tools to rotate the outer tube 15 and the sampling tube 16. The same screw 21 is also threaded onto the first hexagonal block 19 and the second hexagonal block 20. When not sampling, the screw 21 is used to fix the first hexagonal block 19 and the second hexagonal block 20 together, thereby securing the outer tube 15 and... The sampling tube 16 is fixed as a whole. At this time, the outer wall part of the sampling tube 16 without the spiral groove 18 is sealed at the feed hole 17 of the outer tube 15 to prevent material from entering. The screw 21 is also used as a positioning mark. When the screw 21 is at the top, it indicates that the feed hole 17 is facing upward, which makes it easy for personnel to accurately judge the relative position of the outer tube 15 and the sampling tube 16. When sampling is required, loosening the screw 21 can release the locking state of the outer tube 15 and the sampling tube 16, so that the two can rotate independently.

[0048] Example 4 refer to Figure 3-4 In a plurality of feeding plates 6, except for the bottommost plate which is a complete plate, the other feeding plates 6 are provided with multiple equidistant dispersing holes 10. The dispersing holes 10 on each feeding plate 6 are staggered vertically. When soil particles fall into the topmost feeding plate 6 through the inlet, they move downwards along the plate surface. Some soil particles pass through the dispersing holes 10 and fall into the next feeding plate 6, while soil particles that do not pass through the dispersing holes 10 continue to move along the plate surface to the nozzle 9. The high-speed airflow from the nozzle 9 disperses and lifts these soil particles. Soil particles that pass through the dispersing holes 10 continue to fall into the next feeding plate 6, and the above dispersion process is repeated on that feeding plate 6. This process continues until the particles finally fall onto the bottommost complete feeding plate 6. Through the above structure, Soil particles are dispersed on each layer of the feeding plate 6. Due to the staggered arrangement of the dispersing holes 10 in each layer, the soil particles are dispersed multiple times during the fall, avoiding concentrated falling of soil particles. Since the dispersing holes 10 are set at equal intervals, the soil particles can be evenly distributed on each layer of the feeding plate 6, without any local overabundance or underabundance of particles. Combined with the staggered arrangement of the dispersing holes 10 in each layer, the soil particles are evenly dispersed in the vertical falling direction, which significantly improves the uniformity of soil particle dispersion before entering the air classifier box 5. At the same time, the blowing hole 8 is a narrow and long hole, and the length of the nozzle 9 is equal to the length of the blowing hole 8. The airflow ejected by the nozzle 9 is a narrow and long airflow, which can further disperse and lift the soil particles falling from each layer of the feeding plate 6, thereby improving the air classification effect.

[0049] Example 5 refer to Figure 5The nozzle 9 has a trapezoidal structure, with one of its inclined surfaces having the same inclination as the feed plate 6. This inclined surface is continuous with the corresponding feed plate 6 to ensure a smooth transition when soil particles move along the surface of the feed plate 6 to the nozzle 9, avoiding particle accumulation due to structural abrupt changes. The nozzle 9 has an internal cavity 91 to accommodate airflow generated by an external air source. The side of the nozzle 9 closest to the air classifier box 5 has a long, flat air outlet 92, which is connected to the cavity 91. The air outlet 92 gradually narrows from the inside to the outside, making the cross-section of the air outlet channel successively flattened, thereby compressing the airflow and increasing the flow velocity, improving the ability to disperse soil particles. At the same time, the air outlet 92 is inclined upwards, so that the direction of the ejected airflow is obliquely upwards, lifting the soil particles that move to the nozzle 9 obliquely upwards, giving the soil particles an upward initial velocity when entering the air classifier box 5, prolonging their contact time in the airflow, and improving the air classification effect.

[0050] Example 6 refer to Figure 6 The two sides of the feeding plate 6 are fixed with guide plates 11. The two guide plates 11 tighten in sequence along the inclined direction of the feeding plate 6, and gather the soil particles on the feeding plate 6 towards the center. The distance between the closest ends of the two guide plates 11 is equal to the distance between the farthest ends of the two sampling components 14 in the same collection hopper 12, so that the gathered soil particles can fall as far as possible into the sampling area of ​​the sampling component 14, so as to ensure that the sampling component 14 can collect representative samples.

[0051] Working principle: The screening device 1 crushes and screens the dry soil to below 2mm, and then sends it into the feeding box 4 via the conveying device 2. After the soil particles fall into the feeding box 4 through the inlet, they fall down step by step along the multi-layer feeding plate 6. Some particles pass through the staggered material dispersing holes 10 of each layer, while the remaining particles move along the plate surface to the nozzle 9 and are blown away by the high-speed airflow. This process is repeated layer by layer, so that the soil particles are dispersed multiple times during the falling process, avoiding concentrated falling. At the same time, the narrow, upward-sloping high-speed airflow sprayed from the nozzle 9 further disperses and lifts the soil particles that have moved to the nozzle 9, so that the soil particles enter the air classifier box 5 evenly and loosely.

[0052] After entering the air classifier 5, under the action of the horizontal airflow, due to the different densities of light and heavy soil particles, the heavy soil particles settle faster and have a shorter horizontal displacement, falling into the near-end area of ​​the air classifier 5; the light soil particles settle slower and have a longer horizontal displacement, and are carried by the airflow to the far-end area of ​​the air classifier 5, thus achieving the separation of light and heavy soil particles.

[0053] After separation, the soil particles are guided by triangular wedges 13. Heavy particles fall into the left collection hopper 12, and light particles fall into the right collection hopper 12. Two sampling components 14 in each collection hopper 12 are inserted along the material accumulation slope. Operators can rotate the sampling tube 16 to gradually connect the spiral groove 18 with the feed hole 17 of the outer tube 15, so as to achieve continuous spatial sampling at different positions along the length of the feed hole 17 and test the light particles. If the pollutant content of the light soil particles meets the standard, they can be directly reused; if they do not meet the standard, the dosage of the reagent is determined according to the test results and subsequent treatment is carried out. At the same time, the heavy soil particles will also enter the subsequent remediation treatment, thereby achieving precise classification and remediation of contaminated soil.

[0054] The pretreatment method for contaminated soil includes the following steps: S1: The dry soil is fed into the screening device 1 for crushing and screening, and soil particles with a particle size of less than 2mm are screened out. S2: The soil particles screened in S1 are conveyed to the feeding box 4 via the conveying device 2. The soil particles fall into the multi-layer feeding plate 6 in the feeding box 4 through the inlet and move downward along the surface of the feeding plate 6. Some of the soil particles pass through the dispersing hole 10 and fall to the next layer of the feeding plate 6. The soil particles that do not pass through the dispersing hole 10 continue to move along the plate surface to the nozzle 9. The dispersing holes 10 on each layer of the feeding plate 6 are arranged in a staggered manner in the vertical direction, so that the soil particles are dispersed multiple times during the falling process to avoid concentrated falling. S3: Nozzle 9 ejects a high-speed airflow, which blows away the soil particles that have moved to nozzle 9 and lifts them obliquely upward, so that the soil particles enter the air classifier box 5 evenly and loosely. S4: Soil particles entering the air classifier 5 are separated according to density differences under the action of airflow. Heavy soil particles settle faster and have a shorter horizontal displacement, falling into the near end area of ​​the air classifier 5. Light soil particles settle slower and have a longer horizontal displacement, being carried by the airflow to the far end area of ​​the air classifier 5, thus achieving the separation of light and heavy soil particles. S5: After separation, the heavy soil particles are guided by the triangular wedge 13 to fall into the left collection hopper 12, and the light soil particles are guided by the triangular wedge 13 to fall into the right collection hopper 12. S6: Samples are taken from each collection hopper 12 by sampling component 14, and the spiral groove 18 is gradually connected to the feed hole 17 of outer tube 15 by rotating sampling tube 16. Spatial continuous sampling is carried out at different positions along the length of feed hole 17, and the extracted lightweight soil particles are tested. S7: Based on the test results of S6, if the pollutant content of the lightweight soil particles meets the standard, it can be reused directly; if it does not meet the standard, the dosage of the agent will be determined based on the test results, and subsequent remediation treatment will proceed.

[0055] 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 contaminated soil pretreatment device, characterized in that, Includes a screening device (1) for crushing and screening dry soil to screen out soil particles with a particle size within a set range; A conveying device (2) is installed at the discharge end of the screening device (1) for conveying the screened soil particles; The air separation device (3) is set at the discharge end of the conveying device (2) and is used to air separate the soil particles conveyed by the conveying device (2) into light soil particles and heavy soil particles. The collection hopper (12) is located at the bottom of the air separation device (3) and is used to collect light soil particles and heavy soil particles separated by air separation respectively. The sampling component (14) is set on the collection hopper (12) and is used to collect soil samples from the collection hopper (12) when the equipment is running, so as to detect the lightweight soil particles and determine whether they meet the direct reuse standard.

2. The contaminated soil pretreatment equipment according to claim 1, characterized in that, The air separation device (3) includes a feeding box (4) and an air separation box (5). The top of the feeding box (4) is provided with a feeding port for receiving soil particles conveyed by the conveying device (2). The air separation box (5) is connected to the discharge end of the feeding box (4). A partition (7) is provided between the feeding box (4) and the air separation box (5). A blowing hole (8) is provided on the partition (7). A nozzle (9) is fixed in the blowing hole (8). The nozzle (9) is connected to an external air source through a pipeline.

3. The contaminated soil pretreatment equipment according to claim 2, characterized in that, The material box (4) has multiple inclined material plates (6) continuously fixed inside from top to bottom. Among the multiple material plates (6), except for the one at the bottom which is a complete plate, the other material plates (6) are provided with multiple equidistant material dispersing holes (10). The material dispersing holes (10) on each material plate (6) are staggered in the vertical direction to disperse the soil particles multiple times during the falling process.

4. The contaminated soil pretreatment equipment according to claim 2, characterized in that, The nozzle (9) has a cavity (91) inside. The nozzle (9) has a long, flat air outlet (92) on the side near the air separator (5). The air outlet (92) is connected to the cavity (91), and the air outlet (92) gradually narrows from the inside to the outside and is tilted upwards.

5. The contaminated soil pretreatment equipment according to claim 1, characterized in that, Two sampling components (14) are installed in the same collection hopper (12). Both sampling components (14) are inserted obliquely upward from the left side wall of the collection hopper (12) and extend to the right side inside the collection hopper (12). The distance between the two sampling components (14) gradually increases from left to right, and the whole is arranged in a V shape. The tilting direction of the sampling components (14) is consistent with the direction of the material accumulation slope in the collection hopper (12).

6. The contaminated soil pretreatment equipment according to claim 1, characterized in that, The sampling assembly (14) includes an outer tube (15) and a sampling tube (16). The outer tube (15) is installed on the wall of the hopper (12). Part of the outer tube (15) extends into the hopper (12). The section of the outer tube (15) located in the hopper (12) has a feed elongated hole (17). The sampling tube (16) is rotatably and sealed to the inside of the outer tube (15). A spiral groove (18) is provided on the outer wall of the sampling tube (16). The spiral groove (18) has fewer than one turn, and the axial length of the spiral groove (18) is equal to the length of the feed elongated hole (17). The outer wall of the sampling tube (16) without the spiral groove (18) can completely block the feed elongated hole (17).

7. The contaminated soil pretreatment equipment according to claim 6, characterized in that, The outer tube (15) is fixedly installed on the wall of the hopper (12).

8. The contaminated soil pretreatment equipment according to claim 6, characterized in that, The outer tube (15) is rotatably installed on the wall of the collection hopper (12). Multiple protrusions (22) are fixedly provided on the outer wall of the pipe section inside the collection hopper (12) of the outer tube (15) to disturb the soil particles inside the collection hopper (12) when rotating.

9. The contaminated soil pretreatment equipment according to claim 8, characterized in that, The end of the outer tube (15) is fixed with a first hexagonal block (19), and the end of the sampling tube (16) extending out of the outer tube (15) is fixed with a second hexagonal block (20). The first hexagonal block (19) and the second hexagonal block (20) are detachably mounted with the same screw (21) for fixing the outer tube (15) and the sampling tube (16) into one piece.

10. A method for pretreating contaminated soil, using the contaminated soil pretreatment equipment according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1: The dry soil is fed into the screening device (1) for crushing and screening to obtain soil particles with a particle size ≤2mm; S2: The sieved soil particles are fed into the feeding box (4) by the conveying device (2), and fall down through multiple feeding plates (6) in stages. Some particles pass through the dispersing holes (10), and the remaining particles move along the plate surface to the nozzle (9). The dispersing holes (10) of each layer are arranged vertically and alternately, so that the particles are dispersed multiple times during the falling process. S3: The nozzle (9) sprays out a high-speed airflow, which blows the soil particles apart and lifts them obliquely upwards, so that they enter the air classifier (5) in a uniform and loose manner. S4: Soil particles entering the air separator (5) are separated according to density differences under the action of airflow. Heavy soil particles fall into the near end area, while light soil particles are carried to the far end area. S5: The separated heavy and light soil particles are guided by the triangular wedge (13) to fall into the left and right collection hoppers (12) respectively. S6: Samples are taken from each collection hopper (12) by sampling component (14), and the sampling tube (16) is rotated to connect the spiral groove (18) with the feed hole (17) of the outer tube (15). Samples are continuously taken at different positions along the length of the feed hole (17) to detect the light soil particles. S7: If the lightweight soil particles meet the standards according to the test results, they can be reused directly; if they do not meet the standards, the dosage of the agent will be determined according to the test results, and subsequent remediation treatment will be carried out.

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