Microplastic extraction apparatus and method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-04-14
Smart Images
Figure CN121847338A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microplastic extraction technology, and in particular to a microplastic extraction device and method. Background Technology
[0002] Microplastics refer to plastic fragments or particles with a diameter of less than 5 mm. As a new type of pollutant, microplastics are widely present in soil. Accurate and efficient separation and extraction of microplastics from soil is a prerequisite for conducting research on their environmental behavior, ecological risk assessment, and pollution control.
[0003] In related technologies, lumpy soil is broken up and mixed with a salt solution of a specific density in a flotation cylinder. Most microplastics, being of low density, float to the surface, and are then retrieved from the surface. However, existing methods have the following drawbacks: density flotation can only float microplastics with lower densities and is not suitable for microplastics with higher densities; furthermore, some organic matter in the soil also floats to the surface and mixes with the microplastics, increasing the difficulty of subsequent identification and sorting; additionally, existing methods involve a lot of manual operation, are time-consuming, and cannot meet the needs of processing large batches of samples. Summary of the Invention
[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a microplastic extraction device that can achieve efficient, continuous, and automated extraction of microplastics, and has the advantages of good extraction effect, wide applicability, and minimal interference from impurities.
[0005] This application also proposes a method for microplastic extraction.
[0006] A microplastic extraction device according to a first aspect embodiment of this application includes a frame, a crushing mechanism, a screening box, a screening disc, and an electrostatic separator. The crushing mechanism is disposed on the frame, the screening box is connected to the discharge port of the crushing mechanism, the bottom end of the screening box is through-hole, the screening disc is rotatably mounted on the frame, the top end of the screening disc extends into the bottom of the screening box and closes the bottom of the screening box, the outer peripheral wall of the screening disc is provided with screening holes, and the electrostatic separator is disposed on the frame and located at the... Below the screening disc; wherein, the crushing mechanism is used to crush the soil and send it to the screening box; when the screening disc rotates to the point where the screening holes are located in the screening box, crushed material with a particle size smaller than the aperture of the screening holes falls into the screening holes; when the screening holes move out of the screening box with the screening disc, the crushed material in the screening holes falls into the electrostatic separator; the electrostatic separator is used to charge the microplastics in the crushed material and to cause the microplastics to deflect in a specific direction through the action of an electric field, thereby separating them from the falling soil particles.
[0007] The microplastic extraction device according to the embodiments of this application has at least the following beneficial effects:
[0008] This application employs the principle of electrostatic separation, which relies on the difference in the charged properties of materials, rather than density, for separation. Therefore, whether low-density or high-density microplastics, as long as their charged properties differ from those of soil particles, they can be effectively separated, greatly expanding the range of extractable microplastics. Most organic matter exhibits similar charged behavior to soil particles, but also differs significantly, making microplastics more prone to charging and deflection, thus significantly improving extraction purity. Furthermore, the screening holes on the outer wall of the screening disc not only enable automatic quantitative feeding of materials, improving process standardization, but also ensure more uniform distribution of crushed material, resulting in better microplastic charging and enhanced electrostatic separation. It also allows for soil screening, preventing large plant impurities and stones from interfering with or damaging the electrostatic separator during microplastic extraction.
[0009] According to some embodiments of this application, the outer peripheral wall of the screening disc is provided with multiple sets of screening holes arranged circumferentially along the screening disc, and the diameter of each set of screening holes is different. The screening disc can be rotated so that the screening holes of different sets are sequentially located in the bottom of the screening box.
[0010] According to some embodiments of this application, the outer peripheral wall of the screening disc is provided with a residual material trough, and the residual material trough and the screening holes are arranged along the circumference of the screening disc. When the screening disc rotates so that the residual material trough is located in the bottom of the screening box, the crushed material that has not fallen into the screening holes is collected.
[0011] According to some embodiments of this application, a partition is provided below the screening disc, and the frame forms an extraction channel and a residual material channel on both sides of the partition, respectively. The screening disc can rotate in a first direction so that the crushed material released from the screening holes falls into the extraction channel, and can rotate in the opposite second direction so that the crushed material released from the residue trough falls into the residue channel.
[0012] According to some embodiments of this application, the top surface of the partition is configured as an arc surface coaxial with the screening disc, and the bottom surface of the screening disc is in contact with the top surface of the partition.
[0013] According to some embodiments of this application, the screening box includes: Two opposing first walls, with the two axial end faces of the screening disc respectively abutting the inner sides of the two first walls; Two opposing second walls, the outer peripheral wall of the screening disc is attached to the bottom ends of the two second walls.
[0014] According to some embodiments of this application, scrapers are provided on the inner sides of the two second walls, the two sides of the scrapers are attached to the two first walls, and the bottom end of the scrapers abuts against the outer peripheral wall of the screening disc.
[0015] According to some embodiments of this application, an atomizing nozzle is also included, disposed on the frame, for spraying water mist onto the shredded material as it falls from the sieve holes into the electrostatic separator.
[0016] According to some embodiments of this application, the electrostatic separator includes a corona electrode and a parallel plate electrode. The corona electrode is used to charge the microplastics in the crushed material released from the sieve orifice. The parallel plate electrode is located below the corona electrode and is used to generate an electric field to cause the charged microplastics to be directionally deflected.
[0017] According to the microplastic extraction method of the second aspect of this application, based on the microplastic extraction device described in the first aspect of the embodiment, the method includes the following steps: The soil is crushed to form a crushed material, which is then sent to the screening box. Rotate the screening disc so that the screening holes are located inside the screening box to receive the crushed material; Rotate the screening disc to move the screening holes out of the screening box and release the crushed material into the electrostatic separator; The electrostatic separator charges the microplastics in the crushed material and causes them to deflect in a specific direction under the influence of an electric field, thereby separating them from the falling soil particles.
[0018] The microplastic extraction method according to the embodiments of this application has at least the following beneficial effects: The microplastic extraction equipment according to the first aspect of this application can achieve efficient, continuous and automated extraction of microplastics, and has the advantages of good extraction effect, wide applicability and less interference from impurities.
[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and some of these additional aspects and advantages will become apparent from the description or may be learned by practice of this application. Attached Figure Description
[0020] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the overall structure of the microplastic extraction equipment; Figure 2 A schematic diagram showing the rotation direction of the screening disc after the sieving holes receive the crushed material; Figure 3 This is a schematic diagram showing the rotation direction of the screening disc after the shredded material is received in the waste material trough.
[0021] Icon labels: Frame 100; partition 101; extraction channel 102; waste material channel 103; 200 grinding mechanism; Screening box 300; First wall 301; Second wall 302; Scraper 303; Screening disc 400; Screening holes 401; Residue trough 402; Electrostatic separator 500; Corona electrode 501; Parallel plate electrode 502; Atomizing nozzle 600; First receiving box 700; Second receiving box 800. Detailed Implementation
[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0023] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are 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, and therefore should not be construed as a limitation of this application.
[0024] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.
[0025] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.
[0026] The following is for reference. Figures 1 to 3 This application describes a microplastic extraction apparatus and method according to embodiments thereof.
[0027] refer to Figures 1 to 3 As shown, the microplastic extraction device according to the first aspect of this application includes a frame 100, a crushing mechanism 200, a screening box 300, a screening disc 400, and an electrostatic separator 500.
[0028] The crushing mechanism 200 is located on the frame 100. The crushing mechanism 200 may include a box and a stirring shaft located inside the box. The stirring shaft is equipped with stirring blades and can be connected to a drive motor. The top of the box may be equipped with a feed hopper and the bottom is equipped with a discharge port. The collected soil is fed into the box through the feed hopper. The drive motor drives the stirring shaft to rotate, and the stirring shaft drives the stirring blades to rotate, thereby crushing the lumpy soil into crushed material.
[0029] The top of the screening box 300 can be connected to the discharge port at the bottom of the crushing mechanism 200, and the bottom of the screening box 300 is through. The screening box 300 can be a square box.
[0030] The screening disc 400 is rotatably mounted on the frame 100, for example, it can be rotatably mounted on the frame 100 about a horizontal axis. The screening disc 400 can be connected to a drive motor, which drives the screening disc 400 to rotate. The top of the screening disc 400 extends into the bottom of the screening box 300 and seals the bottom of the screening box 300. That is, the top of the screening disc 400 and the bottom of the screening box 300 are in a sealed fit. The screening box 300 does not obstruct the rotation of the screening disc 400, while the screening disc 400 seals the bottom of the screening box 300 to prevent the crushed material inside the screening box 300 from falling out. The outer peripheral wall of the screening disc 400 is provided with screening holes 401. There can be multiple screening holes 401. During the rotation of the screening disc 400, at least some of the screening holes 401 can be located at the bottom of the screening box 300. The crushed material with a particle size smaller than the aperture of the screening hole 401 falls into the screening hole 401, while the crushed material with a particle size larger than the aperture of the screening hole 401, such as large plant impurities and stones, cannot enter the screening hole 401, thereby achieving screening. Afterwards, the screening holes 401 can be rotated out from the bottom of the screening box 300.
[0031] An electrostatic separator 500 is mounted on the frame 100 and located below the screening disc 400. The electrostatic separator 500 can charge microplastics, while soil particles, due to their different dielectric constants, will not be charged or will only carry a trace amount of charge. The electrostatic separator 500 also generates an electric field, which can cause the charged microplastics to deflect in a specific direction, while soil particles are less affected by the electric field.
[0032] The crushing mechanism 200 is used to crush the soil and send it to the screening box 300. When the screening disc 400 rotates to the screening hole 401 inside the screening box 300, the crushed material with a particle size smaller than the aperture of the screening hole 401 falls into the screening hole 401. When the screening hole 401 moves out of the screening box 300 with the screening disc 400, the crushed material in the screening hole 401 falls into the electrostatic separator 500. The electrostatic separator 500 is used to charge the microplastics in the crushed material and to cause the microplastics to deflect in a specific direction through the action of an electric field, thereby separating them from the falling soil particles.
[0033] This application employs the principle of electrostatic separation, which relies on the difference in the charged properties of materials rather than their density. Therefore, whether the microplastics are low-density or high-density, as long as their charged properties differ from those of soil particles, they can be effectively separated, greatly expanding the range of extractable microplastics. Most organic matter exhibits similar charged behavior to soil particles, but also differs significantly from them; microplastics are more easily charged and deflected, thus significantly improving extraction purity. Furthermore, the screening holes on the outer periphery of the screening disc 400 not only enable automatic quantitative feeding of materials, improving process standardization, but also ensure more uniform distribution of the crushed material, resulting in better charging of microplastics and enhanced electrostatic separation. It also allows for soil screening, preventing large plant impurities and stones from interfering with or damaging the electrostatic separator 500 during microplastic extraction.
[0034] refer to Figure 2 and Figure 3 As shown, in some embodiments of this application, the outer peripheral wall of the screening disc 400 is provided with multiple sets of screening holes 401 arranged circumferentially along the screening disc 400. The diameter of each set of screening holes 401 is different, and the screening disc 400 can be rotated so that the screening holes 401 of different sets are sequentially located in the bottom of the screening box 300. For example, the outer peripheral wall of the screening disc 400 can be formed with multiple screening sections along the circumferential direction, and the screening holes 401 of different sets are respectively opened in different screening sections. There can be multiple screening holes 401 in the same set, for example, multiple rows can be arranged along the axial direction of the screening disc 400, and each row can include multiple screening holes 401 arranged circumferentially along the screening disc 400.
[0035] In this embodiment, the screening disc 400 is rotated so that different groups of screening holes 401 are sequentially located at the bottom of the screening box 300. The feeding amount of the automatic quantitative feed can be adjusted according to the needs. In addition, different groups of screening holes 401 can be sequentially located at the bottom of the screening box 300 according to the aperture size from small to large. This allows microplastics of different sizes to enter the screening holes 401 of different aperture sizes, realizing the graded extraction of microplastics of different sizes, which makes it more convenient to study the content of microplastics of different sizes in the soil.
[0036] refer to Figure 2 and Figure 3 As shown, in some embodiments of this application, the outer peripheral wall of the screening disc 400 is provided with a material trough 402. The material trough 402 and the screening holes 401 are arranged along the circumference of the screening disc 400. When the screening disc 400 rotates so that the material trough 402 is located in the bottom of the screening box 300, the crushed material that has not fallen into the screening holes 401 is collected.
[0037] The soil may contain large stones and plant impurities that cannot fall into the screening holes 401 and will accumulate in the screening box 300, forming residual material that affects the subsequent screening of microplastics. The top of the screening box 300 is connected to the crushing mechanism 200, and the bottom is inserted by the top of the screening disc 400, making it inconvenient to remove and prone to causing residual material to spill out when removed.
[0038] In this embodiment, when the screening disc 400 rotates until the residue trough 402 aligns with the bottom of the screening box 300, residual impurities that are too large to pass through the screening holes 401 are automatically collected into the residue trough 402. Then, by rotating the residue trough 402 out of the bottom of the screening box 300, the residue is released. This design avoids the cumbersome operation of disassembling the screening box 300 to clean the residue, as required by traditional structures. It not only eliminates potential material spillage during disassembly but also significantly improves the automation and continuity of equipment operation. The periodic cleaning function of the residue trough 402 ensures a suitable screening environment within the screening box 300, thereby ensuring the stable and efficient microplastic screening process and preventing confusion with subsequent soil samples, which could affect the detection of microplastic content.
[0039] refer to Figures 1 to 3 As shown, in some embodiments of this application, a partition 101 is provided below the screening disc 400, and the frame 100 forms an extraction channel 102 and a residual material channel 103 on both sides of the partition 101 respectively; the screening disc 400 can rotate in a first direction so that the crushed material released from the screening hole 401 falls into the extraction channel 102, and can rotate in the opposite second direction so that the crushed material released from the residual material trough 402 falls into the residual material channel 103.
[0040] In this embodiment, by controlling the forward and reverse rotation of the sieving disc 400, and in conjunction with the extraction channel 102 and the residue channel 103 formed by the partition 101, the automatic and physical separation and guided collection of small-sized crushed material mixed with most microplastics and large-particle residue are achieved. This further optimizes the sieving and extraction process, prevents cross-contamination, and makes sample collection more orderly and efficient.
[0041] refer to Figure 1 As shown, in some embodiments of this application, the top surface of the partition 101 is configured as an arc surface coaxial with the screening disk 400, and the bottom surface of the screening disk 400 is in contact with the top surface of the partition 101.
[0042] In this embodiment, the arc surface at the top of the partition 101 is tightly fitted with the bottom surface of the screening disc 400, forming a dynamic sealed flow guiding structure. This effectively guides materials exiting from different directions to accurately fall into the corresponding channels, while also preventing the leakage of fine microplastics from gaps, thus effectively improving the microplastic extraction effect.
[0043] refer to Figures 1 to 3 As shown, in some embodiments of this application, the screening box 300 includes two opposing first walls 301 and two opposing second walls 302. The two axial end faces of the screening disc 400 are respectively attached to the inner sides of the two first walls 301, and the outer peripheral wall of the screening disc 400 is attached to the bottom ends of the two second walls 302.
[0044] In this embodiment, this configuration allows the top of the screening disc 400 to be sealed and fitted to the bottom of the screening box 300, resulting in a better sealing effect on the screening box 300, and without affecting the rotation of the screening disc 400.
[0045] refer to Figure 2 and Figure 3 As shown, in some embodiments of this application, scrapers 303 are provided on the inner sides of the two second walls 302, the two sides of the scrapers 303 are attached to the two first walls 301, and the bottom end of the scrapers 303 abuts against the outer peripheral wall of the screening disc 400. For example, the surface of the scraper 303 may be parallel to the axial direction of the screening disc 400.
[0046] In this embodiment, a scraper 303 is provided. When the screening disc 400 rotates, the bottom end of the scraper 303 can scrape the material from the outer peripheral wall of the screening disc 400, preventing the crushed material outside the screening disc 400 from moving with the screening disc 400 and forming a gap between the outer peripheral wall of the screening disc 400 and the bottom end of the second wall 302 of the screening box 300, which would cause the crushed material in the screening box 300 to be discharged randomly from the gap.
[0047] refer to Figure 1 As shown, in some embodiments of this application, the microplastic extraction device further includes an atomizing nozzle 600 disposed on the frame 100 for spraying water mist onto the crushed material as it falls from the sieve hole 401 into the electrostatic separator 500.
[0048] In this application, the atomizing nozzle 600 sprays water mist onto the falling crushed material, which can slightly increase the overall humidity of the material. This not only helps to suppress the flying of dry soil dust, reducing internal equipment pollution and its impact on operators, but more importantly, appropriate moisture can regulate the surface conductivity of the material. Specifically, it can significantly increase the surface conductivity of soil particles while having a smaller impact on the surface conductivity of microplastics. This, in turn, can significantly reduce the charge on soil particles while having little impact on the charge on microplastics, thereby potentially improving the selectivity and efficiency of electrostatic separation.
[0049] refer to Figure 1As shown, in some embodiments of this application, the electrostatic separator 500 includes a corona electrode 501 and a parallel plate electrode 502. The corona electrode 501 is used to charge the microplastics in the crushed material released from the sieve hole 401. The parallel plate electrode 502 is disposed on the frame 100 and located below the corona electrode 501, and is used to generate an electric field to cause the charged microplastics to be directionally deflected.
[0050] In this embodiment, the corona electrode 501 charges the microplastics, and the uniform electric field formed by the parallel plate electrode 502 causes the charged microplastics to undergo controllable directional deflection. This design provides a clear separation force and stable effect, and the separation effect can be easily optimized by adjusting the voltage parameters. It is suitable for soil and microplastic samples with different properties.
[0051] It should be noted that both the corona electrode 501 and the parallel plate electrode 502 are common structures, and their structures and working principles will not be elaborated here. Furthermore, the electrostatic separator 500 can also have other structures, which will not be described further here.
[0052] refer to Figure 1 As shown, in some embodiments of this application, the top of the parallel plate electrode 502 may be provided with a feed inlet, and the size of the feed inlet along the arrangement direction of the two electrode plates of the parallel plate electrode 502 is smaller than the distance between the two electrode plates of the parallel plate electrode 502.
[0053] In this way, after the crushed material enters through the feed inlet, the soil particles will fall directly downwards, while the microplastics will be deflected to the side directly below the feed inlet under the influence of the electric field, thus facilitating separation from the soil particles.
[0054] refer to Figure 1 As shown, in some embodiments of this application, the frame 100 is provided with two first receiving boxes 700 and second receiving boxes 800. The first receiving box 700 is used to receive the crushed material falling from the residual material channel 103 and the soil particles falling from the extraction channel 102. The second receiving box 800 is used to receive the microplastics falling from the extraction channel 102, so as to facilitate the collection of the screened material.
[0055] According to the microplastic extraction method of the second aspect of this application, based on the microplastic extraction device of the first aspect embodiment described above, the method includes the following steps: The soil is crushed into crushed material and sent to a screening box 300. Rotate the screening disc 400 so that the screening hole 401 is located inside the screening box 300 to receive the crushed material; Rotate the screening disc 400 to move the screening hole 401 out of the screening box 300, and release the crushed material to the electrostatic separator 500. The electrostatic separator 500 charges the microplastics in the crushed material and causes them to deflect in a specific direction under the action of an electric field, thereby separating them from the falling soil particles.
[0056] According to the method of the embodiments of this application, by employing the microplastic extraction equipment of the first aspect of this application, the method can achieve efficient, continuous and automated extraction of microplastics, and has the advantages of good extraction effect, wide applicability and less interference from impurities.
[0057] It should be noted that since the method can adopt all the technical solutions of the microplastic extraction device of the first aspect embodiment, it has at least all the beneficial effects brought about by the technical solutions of the first aspect embodiment. These additional beneficial effects will not be elaborated here.
[0058] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.
Claims
1. A microplastic extraction device, characterized in that, include: frame; A crushing mechanism is located on the frame; A screening box is connected to the discharge port of the crushing mechanism, with the bottom of the screening box extending through it; A screening disc is rotatably mounted on the frame. The top of the screening disc extends into the bottom of the screening box and closes the bottom of the screening box. Screening holes are provided on the outer peripheral wall of the screening disc. An electrostatic separator is mounted on the frame and located below the screening disc; The crushing mechanism is used to crush the soil and send it to the screening box. When the screening disc rotates to the point where the screening hole is inside the screening box, the crushed material with a particle size smaller than the aperture of the screening hole falls into the screening hole. When the screening hole moves out of the screening box along with the screening disc, the crushed material in the screening hole falls into the electrostatic separator; The electrostatic separator is used to charge the microplastics in the crushed material and to deflect the microplastics in a specific direction through an electric field, so as to separate them from the falling soil particles.
2. The microplastic extraction device according to claim 1, characterized in that, The outer peripheral wall of the screening disc is provided with multiple sets of screening holes arranged circumferentially along the screening disc. The diameter of each set of screening holes is different. The screening disc can be rotated so that the screening holes of different sets are located sequentially in the bottom of the screening box.
3. The microplastic extraction device according to claim 1, characterized in that, The outer peripheral wall of the screening disc is provided with a residual material trough, and the residual material trough and the screening holes are arranged along the circumference of the screening disc. When the screening disc rotates and the residual material trough is located in the bottom of the screening box, the crushed material that has not fallen into the screening holes is collected.
4. The microplastic extraction device according to claim 3, characterized in that, A partition is provided below the screening disc, and the frame forms an extraction channel and a residue channel on both sides of the partition, respectively. The screening disc can rotate in a first direction so that the crushed material released from the screening holes falls into the extraction channel, and can rotate in the opposite second direction so that the crushed material released from the residue trough falls into the residue channel.
5. The microplastic extraction device according to claim 4, characterized in that, The top surface of the partition is configured as an arc surface coaxial with the screening disc, and the bottom surface of the screening disc is in contact with the top surface of the partition.
6. The microplastic extraction device according to claim 1, characterized in that, The screening box includes: Two opposing first walls, with the two axial end faces of the screening disc respectively abutting the inner sides of the two first walls; Two opposing second walls, the outer peripheral wall of the screening disc is attached to the bottom ends of the two second walls.
7. The microplastic extraction device according to claim 6, characterized in that, Scrapers are provided on the inner sides of the two second walls, and the two sides of the scrapers are respectively attached to the two first walls, with the bottom end of the scrapers abutting against the outer peripheral wall of the screening disc.
8. The microplastic extraction device according to claim 1, characterized in that, Also includes: An atomizing nozzle, disposed on the frame, is used to spray water mist onto the pulverized material as it falls from the sieve holes into the electrostatic separator.
9. The microplastic extraction device according to claim 1, characterized in that, The electrostatic separator includes: A corona electrode is used to charge the microplastics in the crushed material released from the sieve orifice; A parallel plate electrode, located below the corona electrode, is used to generate an electric field to cause the charged microplastics to undergo directional deflection.
10. A method for extracting microplastics, based on the microplastic extraction equipment according to claim 1, characterized in that, include: The soil is crushed into a crushed material and sent to the screening box; Rotate the screening disc so that the screening holes are located inside the screening box to receive the crushed material; Rotate the screening disc to move the screening holes out of the screening box and release the crushed material into the electrostatic separator; The electrostatic separator charges the microplastics in the crushed material and causes them to deflect in a specific direction under the influence of an electric field, thereby separating them from the falling soil particles.