A device for separating microplastics in soil

Abstract

The invention provides a device for separating microplastics in soil, belonging to the technical field of microplastic processing, comprising: a casing equipped with a human-computer interaction page, a liquid separation mechanism, a stirring component, a circulation mechanism, and a separation tank, wherein an oil tank and a water tank are respectively installed on the sides of the separation tank; the liquid separation mechanism is used to seal and connect the oil tank and the water tank to the separation tank respectively, and separate the microplastics when controlling the oil tank and the water tank to be respectively connected to the separation tank; the stirring component is used to control the mixing of soil and water or oil to screen out microplastics; the circulation mechanism is used to connect the oil tank and the water tank to the separation tank, and pump the oil or water in the oil tank or the water tank into the separation tank for stirring. The invention utilizes the low-density characteristics of microplastics to flush the soil with water, so that the microplastics float for preliminary separation, and then injects oil into the soil accompanied by water through the lipophilicity of the microplastics, and takes away the excess microplastics when separating water and oil, so as to achieve efficient separation of microplastics and recovery and reuse of oil.

Description

Technical Field

[0001] The present invention relates to the technical field of microplastic processing, and in particular to a device for separating microplastics in soil. Background Art

[0002] Plastic products are widely used in human production and life due to their low cost, strong ductility and stable properties. Since the large-scale production in the 20th century, the output of plastics has increased year by year. However, while making human life more convenient, plastics have caused serious environmental pollution problems due to their low recycling rate and difficulty in decomposition. Among them, "microplastics" as a new type of pollutant has attracted great attention at home and abroad.

[0003] Generally speaking, there are various types of plastics in our lives, such as polyethylene and polystyrene. These compounds are exposed to the natural environment and are exposed to the wind and sun. Although they cannot be completely degraded, they are gradually getting smaller and becoming microplastics that are smaller than particles. In addition, there are a lot of abrasive particles in the cosmetics or cleaning products we use. These particles are small in size and float on the water. The city's sewage treatment plants have no way to handle them, so they cannot decompose and leave the sewage treatment plants freely.

[0004] After being ingested by organisms, microplastics cannot be digested and absorbed in the body, which will lead to malnutrition, affect the immune function of the organism, and eventually cause growth retardation or death of the organism; microplastics will release organic monomers and toxic additives during the migration and transformation process. Toxic additives include a variety of plasticizers, antibacterial agents and flame retardants including bisphenol A and phthalates. These additives have been proven to affect the endocrine function of organisms, induce genetic abnormalities, and harm reproduction and development. When microplastics are enriched through the food chain and enter the human body, they will have health effects on the human body. Therefore, the treatment of microplastics is particularly important.

[0005] Plastic particles smaller than five millimeters are called microplastics, and microplastics mixed in the soil are difficult to deal with. At present, some methods for dealing with soil microplastics have been published. For example, the patent with the existing publication number CN113042351B is called a device for separating microplastics in soil, which uses a combination of sieving and density separation to separate microplastics. However, due to the adsorption of some particles in the soil, the density method still has the effect of incomplete separation of microplastics. In fact, microplastics themselves are lipophilic, and mixing oil with soil can well separate plastics from the soil, but excessive contact between oil and soil will affect the organic content of the soil. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a device for separating microplastics in soil, which separates microplastics by combining water and oil. Water is first injected and stirred to perform preliminary separation of microplastics, and then oil is injected and mixed into the water-containing soil for stirring, thereby improving the separation effect of microplastics and reducing the impact on the organic content of the soil.

[0007] In order to solve the above technical problems, the present invention is solved by the following technical solutions

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A device for separating microplastics in soil, characterized in that it comprises: a housing (1) carrying a human-computer interaction page, a separation tank (3) installed inside the housing (1), and an oil tank (4) and a water tank (5) respectively installed on the sides of the separation tank (3);

[0010] Also includes:

[0011] A liquid separation mechanism (6) is used to seal and connect the oil tank (4) and the water tank (5) to the separation tank (3) respectively, and to separate microplastics when the oil tank (4) and the water tank (5) are controlled to be connected to the separation tank (3) respectively;

[0012] A stirring component (7) for controlling the mixing of soil with water or oil to screen out microplastics;

[0013] The circulation mechanism (8) is used to connect the oil tank (4) and the water tank (5) with the separation tank (3) and pump the oil or water in the oil tank (4) or the water tank (5) into the separation tank (3) for stirring.

[0014] Preferably, the top of the separation tank (3) is a conical structure, the liquid separation mechanism (6) is installed on the inclined surface of the separation tank (3) and is connected to the interior thereof, and the separation tank (3) has a detachable base for loading and unloading soil.

[0015] Preferably, the liquid separation mechanism (6) comprises a first pipe (61), a second pipe (62), and a sealing valve (63); the first pipe (61) is perpendicular to the inclined surface of the separation tank (3) and communicates with the interior thereof; the sealing valve (63) is arranged inside the first pipe (61) and seals the pipe opening thereof; the second pipe (62) is arranged vertically; one end of the second pipe (62) is communicated with the first pipe (61) and the other end is communicated with the oil tank (4) or the water tank (5).

[0016] Preferably, the sealing valve (63) comprises a driver (631), a sealing plug (632), and a guide rod (633); the driver (631) is arranged outside the first pipe (61); the driver (631) is connected to the sealing plug (632) via the protruding guide rod (633); the driver (631) drives the sealing plug (632) to move so that the separation tank (3) is connected to the oil tank (4) or the water tank (5) via the second pipe (62).

[0017] Preferably, the stirring assembly (7) comprises a hollow stirrer (71), a driving motor (72), and a rotating connecting piece (73); the hollow stirrer (71) penetrates into the interior of the separation tank (3) from above and rotates with the separation tank; the driving motor (72) is arranged at the top of the separation tank (3) and drives the hollow stirrer (71) to rotate through a bevel gear transmission; and the rotating connecting piece (73) is installed at the top of the hollow stirrer (71).

[0018] Preferably, the circulation mechanism (8) comprises a drive motor (81), a gear pump (82), and a straight pipe three-way valve (83); one side of the straight pipe three-way valve (83) is connected to the gear pump (82), and the other two ports thereof are respectively connected to the oil tank (4) and the water tank (5); one end of the gear pump (82) is connected to the rotating connecting member (73); the drive motor (81) controls the reversing of the straight pipe three-way valve (83) through a flexible component (84); and the drive motor (81) controls the operation of the gear pump (82) through a one-way control mechanism (85).

[0019] Preferably, the straight pipe three-way valve (83) comprises a first interface (831), a second interface (832), and a piston (833); the first interface (831) is located in the middle of the valve body of the straight pipe three-way valve (83) and is connected to the gear pump (82); two second interfaces (832) are symmetrically arranged on both sides of the first interface (831) and are respectively connected to the oil tank (4) and the water tank (5) through hoses; the piston (833) is slidably arranged in the middle of the valve body and can seal the first interface (831); one end of the rod of the piston (833) passes through the straight pipe three-way valve (83) and is connected to the flexible component (84); the drive motor (81) drives the piston (833) to move through the flexible component (84), so that the first interface (831) is opened and one of the second interfaces (832) is sealed.

[0020] Preferably, the flexible component (84) comprises a slide plate (841), a rack (842), an elastic member (843), and a connecting member (844); the rack (842) is slidably mounted inside the slide plate (841); the elastic member (843) is symmetrically arranged at the end of the rack (842) and is connected with teeth; one end of the connecting member (844) is fixed to the rack (842) and the other end is connected and fixed to the rod portion of the piston (833); the driving motor (81) drives the rack (842) to move through gear transmission.

[0021] Preferably, the one-way control mechanism (85) comprises a rotating shaft (851) that is rotatably supported, a conical wheel disc (852) symmetrically arranged on the rotating shaft (851), and a ratchet (853) mounted on a side of the conical wheel disc (852); the rotating shaft (851) is in transmission cooperation with the bearing teeth of the gear pump (82); the conical wheel disc (852) is in rotation cooperation with the rotating shaft (851); the ratchet (853) is sleeved on the rotating shaft (851); and a ratchet pawl that meshes with the ratchet (853) is mounted on the conical wheel disc (852).

[0022] Preferably, the two ratchet wheels (853) are centrally symmetrically arranged, a drive shaft is fixed to the end of the output shaft of the drive motor (81), the drive shaft is in transmission cooperation with the rack (842), a cone wheel is sleeved on the end of the drive shaft, and the cone wheel can mesh with the two cone wheel discs (852) at the same time.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a device for separating microplastics in soil. The device utilizes the low density of microplastics to flush the soil with water, allowing the microplastics to float for preliminary separation. The device then uses the lipophilicity of the microplastics to inject oil into the soil accompanied by water. When the water and oil are separated, the excess microplastics are taken away, thereby achieving efficient separation of microplastics and recovery and reuse of oil.

[0025] The present invention adopts water injection for preliminary separation and then oil injection for screening to achieve efficient filtration. At the same time, the water injected first is recovered, and then oil is injected and stirred to allow the oil to quickly contact with the soil and separate using water, thereby reducing the contact time between the oil and the soil and reducing the impact on the organic content of the soil.

[0026] The present invention adopts a driving motor to control the reversing of the straight pipe three-way valve and the operation of the gear pump. The reversing of the straight pipe three-way valve is driven by the forward and reverse rotation of the driving motor. The rotation of the driving motor always controls the gear pump injection operation, thereby avoiding oil-water mixing and insufficient oil recovery.

[0027] In the present invention, a hollow stirrer is used to stir the soil, and oil or water is injected through the middle of the hollow stirrer to quickly mix it with the soil, thereby improving the separation effect of microplastics. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the overall bottom-up structure of the present invention;

[0030] Figure 2 It is a schematic diagram of the front side of the internal component structure of the casing of the present invention;

[0031] Figure 3 It is a schematic diagram of the rear structure of the internal components of the casing of the present invention;

[0032] Figure 4 It is a schematic diagram of the cross-sectional disassembly structure of the separation tank and related components of the present invention;

[0033] Figure 5 It is a schematic diagram of the cross-sectional structure of the liquid separation mechanism of the present invention;

[0034] Figure 6 It is a schematic diagram of the structure of the stirring assembly of the present invention;

[0035] Figure 7 It is a schematic diagram of the circulation mechanism structure of the present invention;

[0036] Figure 8 It is a schematic diagram of the cross-sectional structure of the straight pipe three-way valve of the present invention;

[0037] Fig. 9 It is a schematic diagram of the structure of the flexible component of the present invention;

[0038] Fig.10 It is a schematic diagram of the structure of the one-way control mechanism of the present invention.

[0039] Explanation of the figure numbers: 1. Casing; 3. Separation tank; 4. Oil tank; 5. Water tank; 6. Liquid separation mechanism; 61. First pipeline; 62. Second pipeline; 63. Sealing valve; 631. Driver; 632. Sealing plug; 633. Guide rod; 7. Stirring assembly; 71. Hollow agitator; 72. Driving motor; 73. Rotating connector; 8. Circulation mechanism; 81. Driving motor; 82. Gear pump; 83. Straight pipe three-way valve; 831. First interface; 832. Second interface; 833. Piston; 84. Flexible assembly; 841. Slide plate; 842. Rack; 843. Elastic member; 844. Connector; 85. One-way control mechanism; 851. Rotating shaft; 852. Cone wheel; 853. Ratchet. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings.

[0041] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be used for other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0042] Those skilled in the art should understand that, in the disclosure of the present invention, the directions or positions indicated by the terms "longitudinal", "lateral", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, which are only simplified descriptions for the convenience of describing the present invention, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the above terms should not be understood as limitations on the present invention.

[0043] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity. Example

[0044] See also Figure 1-10 , a device for separating microplastics in soil, comprising: a housing 1 carrying a human-computer interaction page, a separation tank 3 installed inside the housing 1, and an oil tank 4 and a water tank 5 are respectively installed on the sides of the separation tank 3;

[0045] Also includes:

[0046] The liquid separation mechanism 6 is used to seal and connect the oil tank 4 and the water tank 5 to the separation tank 3, and to separate the microplastics when controlling the oil tank 4 and the water tank 5 to be respectively connected to the separation tank 3;

[0047] A stirring component 7, used to control the mixing of soil and water or oil to screen out microplastics;

[0048] The circulation mechanism 8 is used to connect the oil tank 4 and the water tank 5 with the separation tank 3, and pump the oil or water in the oil tank 4 or the water tank 5 into the separation tank 3 for stirring.

[0049] Some implementation methods of the present application are described in detail below with reference to the accompanying drawings:

[0050] The present application uses the separation tank 3 as the center to hold randomly selected soil for separation and extraction of microplastics. A stirring assembly 7 is installed in the separation tank 3 to stir the soil. An oil tank 4 and a water tank 5 are respectively arranged on both sides of the separation tank 3. The oil or water in the oil tank 4 and the water tank 5 are respectively injected into the separation tank 3 through a circulation mechanism 8. It should be noted that the soil in the separation tank 3 should be stirred when the oil or water is injected, and the low density and lipophilicity of the microplastics are utilized to separate the microplastics from the soil.

[0051] The top of the separation tank 3 adopts a conical structure, and the bottom adopts a columnar structure. The cone is wide at the top and narrow at the bottom. A liquid separation mechanism 6 is installed vertically on the cone. The liquid separation mechanism 6 is also connected to the oil tank 4 or the water tank 5, and is used for water or oil to adsorb microplastics and then flow back to the oil tank 4 and the water tank 5. The bottom of the main body is a detachable base, which is used to place samples or take soil for separating microplastics each time the base is removed.

[0052] In the present application, two liquid separation mechanisms 6 are symmetrically arranged on both sides of the separation tank 3, and the two liquid separation mechanisms 6 are respectively connected to the oil tank 4 and the water tank 5. The liquid separation mechanism 6 is in a sealed state. After the separation tank 3 completes the separation of microplastics, the liquid separation mechanism 6 is opened to allow the upper water or oil to flow back into the oil tank 4 and the water tank 5. Among them, the liquid separation mechanism 6 is composed of a first pipe 61, a second pipe 62, and a sealing valve 63. The first pipe 61 is used to communicate with the separation tank 3, and the second pipe 62 is used to communicate with the oil tank 4 or the water tank 5. The first pipe 61 is connected to the second pipe 62, and water or oil flows back through the first pipe 61 and the second pipe 62. The sealing valve 63 is installed inside the first pipe 61, and the opening of the separation tank 3 is sealed.

[0053] During the implementation process, the first pipeline 61 is arranged perpendicular to the inclined surface of the separation tank 3 and connected with its interior, the sealing valve 63 seals the pipe mouth of the first pipeline 61, and the second pipeline 62 is vertically arranged in the middle of the first pipeline 61 to be connected. By driving the sealing valve 63 to open, water and oil reflux is achieved.

[0054] The sealing valve 63 is composed of a driver 631, a sealing plug 632, a guide rod 633, etc. The sealing plug 632 is slidably arranged in the first pipe 61 and seals. The driver 631 is arranged outside the first pipe 61 and is connected to the sealing plug 632 through the guide rod 633. By driving the sealing plug 632 to move, water and oil reflux is achieved.

[0055] In the present application, the stirring component 7 stirs the soil when injecting water or oil into the separation tank 3, and takes advantage of the low density and lipophilicity of microplastics to achieve rapid separation of microplastics and improve the separation effect.

[0056] It should be noted that the stirring assembly 7 is composed of a hollow agitator 71, a driving motor 72, and a rotating connecting piece 73. The hollow agitator 71 is vertically inserted from the top of the separation tank 3. The driving motor 72 is installed on the top of the separation tank 3. The driving motor 72 drives the hollow agitator 71 to rotate through a bevel gear transmission. The hollow agitator 71 is used to stir the soil. A rotating connecting piece 73 is installed on the top of the hollow agitator 71. The hollow agitator 71 is connected to the gear pump 82 for oil or water injection through the rotating connecting piece 73. The rotating connecting piece 73 is used to prevent the hollow agitator 71 from affecting the oil or water injection when rotating.

[0057] In the present application, the circulation mechanism 8 includes a hose, a drive motor 81, a gear pump 82, a straight pipe three-way valve 83, etc. The two hoses are respectively connected to the oil tank 4 and the water tank 5, and the other end of the hose is connected to the straight pipe three-way valve 83, the straight pipe three-way valve 83 is connected to the gear pump 82, and the gear pump 82 is connected to the rotating connector 73. Oil or water is respectively injected into the gear pump 82 through the pressurization. The drive motor 81 controls the reversing of the straight pipe three-way valve 83 through the flexible component 84 to realize the switching of oil injection or water injection. The drive motor 81 also controls the gear pump 82 to work through the one-way control mechanism 85.

[0058] First, a driving shaft is fixed on the output shaft of the driving motor 81 , a gear is installed on the driving shaft for transmission cooperation with the flexible component 84 , and a cone wheel is installed at the end of the driving shaft for transmission cooperation with the one-way control mechanism 85 .

[0059] It should be noted that a first interface 831 and a second interface 832 are provided on the straight pipe three-way valve 83, and a piston 833 is installed inside the straight pipe three-way valve 83. The first interface 831 is located in the middle of the valve body of the straight pipe three-way valve 83 and is connected to the gear pump 82. The two second interfaces 832 are symmetrically arranged on both sides of the first interface 831 and are respectively connected to the oil tank 4 and the water tank 5 through hoses. The piston 833 is slidably arranged in the middle of the valve body to seal the first interface 831. The rod of the piston 833 passes through the straight pipe three-way valve 83 from one end and is connected to the flexible component 84. The driving motor 81 drives the piston 833 to move through the flexible component 84, so that the first interface 831 is open and one of the second interfaces 832 is sealed.

[0060] In the straight pipe three-way valve 83, the initial piston position 833 is in the middle of the stem valve body, sealing the first interface 831. In the working state, the flexible component 84 will drive the piston 833 to move and seal one of the second interfaces 832, that is, the other second interface 832 is connected to the first interface 831 to achieve oil or water injection.

[0061] It should be noted that, when performing microplastic separation, the present application needs to first fill the separation tank 3 with water, let the water level be higher than the liquid separation mechanism 6, and then use the bottom density of the microplastics to suspend them, and after opening the liquid separation mechanism 6, let the upper microplastics and a small amount of water flow back to the water tank 5. Then, oil is added to the separation tank 3, and the remaining microplastics are adsorbed by the lipophilicity of the microplastics. After standing, the incompatibility of oil and water is used to achieve automatic stratification, and the oil absorbs the microplastics and floats on the upper layer of the water surface. After opening another liquid separation mechanism 6, the upper oil and microplastics are allowed to flow back to the oil tank 4. In addition, liquid level detection devices are installed in both the oil tank 4 and the water tank 5 to identify changes in the liquid level and automatically remind to add oil or water. In addition, the oil tank 4 and the water tank 5 are plugged and installed with a filter near the top, and the microplastics adsorbed in the reflux water or oil are filtered by the filter for recovery.

[0062] After each liquid level detection, the separation tank 3 will have some water left, and the soil will be removed for filtration. In some embodiments, a valve with a filter screen will be installed on the base of the separation tank 3, and the excess water can be filtered out after the microplastics are separated and added to the water tank 5. Therefore, each time the soil sample microplastics are stratified, water needs to be added to the water tank 5 again to facilitate the next use.

[0063] In the present application, the flexible component 84 that drives the straight pipe three-way valve 83 to change direction is composed of a slide plate 841, a rack 842, an elastic member 843, a connecting member 844, etc. The rack 842 is slidably installed inside the slide plate 841, the elastic member 843 is symmetrically arranged at the end of the rack 842 and is connected with teeth, one end of the connecting member 844 is fixed on the rack 842, and the other end is connected and fixed to the rod of the piston 833. The driving motor 81 drives the rack 842 to move through gear transmission, controls the movement of the connecting member 844 and the piston 833, and controls the oil tank 4 hose and the water tank 5 hose to be unobstructed when the driving motor 81 rotates forward and reverse.

[0064] In the present application, the driving motor 81 is connected to the one-way control mechanism 85 through a bevel gear, and the gear pump 82 is driven to work by controlling the one-way control mechanism 85. When the driving motor 81 is transmitted through the one-way control mechanism 85 during forward or reverse rotation, the gear pump 82 always maintains one-way rotation, thereby pumping oil or water in the separation tank 3.

[0065] Specifically, the one-way control mechanism 85 is composed of a rotating shaft 851, a cone wheel disc 852, a ratchet 853, a pawl, etc. Two cone wheel discs 852 are symmetrically arranged on the rotating shaft 851, the ratchet 853 is installed on the side of the cone wheel disc 852, and the pawl is installed on the cone wheel disc 852 and can be unidirectionally meshed with the ratchet 853. In addition, the ratchet 853 is centrally symmetrically arranged, the cone wheel disc 852 and the rotating shaft 851 are rotated in coordination, and the ratchet 853 is sleeved on the rotating shaft 851, so that the cone wheel is meshed with the two cone wheel discs 852 at the same time. When the cone wheel rotates, it will drive the two cone wheel discs 852 to rotate at the same time, and only the pawl on one cone wheel disc 852 is meshed with the ratchet 853. Therefore, whether the cone wheel material rotates forward or reverse, the rotating shaft 851 rotates in a single direction, so that the rotating shaft 851 and the bearing teeth of the gear pump 82 are driven and matched, so that the gear pump 82 always performs a unidirectional conveying operation.

[0066] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A device for separating microplastics in soil, characterized in that: include: A housing (1) carrying a human-machine interactive page, a separation tank (3) installed inside the housing (1), and an oil tank (4) and a water tank (5) respectively installed on the sides of the separation tank (3); Also includes: A liquid separation mechanism (6) is used to seal and connect the oil tank (4) and the water tank (5) to the separation tank (3) respectively, and to separate microplastics when the oil tank (4) and the water tank (5) are controlled to be connected to the separation tank (3) respectively; A stirring component (7) for controlling the mixing of soil with water or oil to screen out microplastics; A circulation mechanism (8) is used to connect the oil tank (4) and the water tank (5) with the separation tank (3) and pump the oil or water in the oil tank (4) or the water tank (5) into the separation tank (3) for stirring; The top of the separation tank (3) is a conical structure, the liquid separation mechanism (6) is installed on the inclined surface of the separation tank (3) and is connected to the interior thereof, and the separation tank (3) has a detachable base for loading and unloading soil; The liquid separation mechanism (6) comprises a first pipeline (61), a second pipeline (62), and a sealing valve (63); the first pipeline (61) is perpendicular to the inclined surface of the separation tank (3) and communicates with the interior thereof; the sealing valve (63) is arranged inside the first pipeline (61) and seals the pipe opening thereof; the second pipeline (62) is arranged vertically; one end of the second pipeline (62) is communicated with the first pipeline (61) and the other end is communicated with the oil tank (4) or the water tank (5); The sealing valve (63) comprises a driver (631), a sealing plug (632), and a guide rod (633). The driver (631) is arranged outside the first pipe (61). The driver (631) is connected to the sealing plug (632) via the protruding guide rod (633). The driver (631) drives the sealing plug (632) to move so that the separation tank (3) is connected to the oil tank (4) or the water tank (5) via the second pipe (62).

2. A device for separating microplastics in soil according to claim 1, characterized in that: The stirring assembly (7) comprises a hollow stirrer (71), a driving motor (72), and a rotating connecting piece (73); the hollow stirrer (71) penetrates into the interior of the separation tank (3) from above and rotates with the separation tank; the driving motor (72) is arranged at the top of the separation tank (3) and drives the hollow stirrer (71) to rotate through a bevel gear transmission; and the rotating connecting piece (73) is installed at the top of the hollow stirrer (71).

3. A device for separating microplastics in soil according to claim 2, characterized in that: The circulation mechanism (8) comprises a driving motor (81), a gear pump (82), and a straight pipe three-way valve (83); one side of the straight pipe three-way valve (83) is in communication with the gear pump (82), and the other two ports thereof are respectively in communication with the oil tank (4) and the water tank (5); one end of the gear pump (82) is in communication with the rotating connecting member (73); the driving motor (81) controls the switching of the straight pipe three-way valve (83) through a flexible component (84); and the driving motor (81) controls the operation of the gear pump (82) through a one-way control mechanism (85).

4. A device for separating microplastics in soil according to claim 3, characterized in that: The straight pipe three-way valve (83) comprises a first interface (831), a second interface (832), and a piston (833); the first interface (831) is located in the middle of the valve body of the straight pipe three-way valve (83) and is connected to the gear pump (82); two second interfaces (832) are symmetrically arranged on both sides of the first interface (831) and are respectively connected to the oil tank (4) and the water tank (5) through hoses; the piston (833) is slidably arranged in the middle of the valve body and can seal the first interface (831); one end of the rod of the piston (833) passes through the straight pipe three-way valve (83) and is connected to the flexible component (84); the driving motor (81) drives the piston (833) to move through the flexible component (84), so that the first interface (831) is opened and one of the second interfaces (832) is sealed.

5. A device for separating microplastics in soil according to claim 4, characterized in that: The flexible component (84) comprises a slide plate (841), a rack (842), an elastic member (843), and a connecting member (844); the rack (842) is slidably mounted inside the slide plate (841); the elastic member (843) is symmetrically arranged at the end of the rack (842) and is connected with teeth; one end of the connecting member (844) is fixed to the rack (842) and the other end is connected and fixed to the rod portion of the piston (833); the driving motor (81) drives the rack (842) to move through gear transmission.

6. A device for separating microplastics in soil according to claim 5, characterized in that: The one-way control mechanism (85) comprises a rotating shaft (851) that is rotatably supported, a cone wheel disc (852) symmetrically arranged on the rotating shaft (851), and a ratchet (853) mounted on the side of the cone wheel disc (852); the rotating shaft (851) is in transmission cooperation with the bearing teeth of the gear pump (82); the cone wheel disc (852) is in rotation cooperation with the rotating shaft (851); the ratchet (853) is sleeved on the rotating shaft (851); and a ratchet pawl that meshes with the ratchet (853) is mounted on the cone wheel disc (852).

7. A device for separating microplastics in soil according to claim 6, characterized in that: The two ratchet wheels (853) are centrally symmetrically arranged, the end of the output shaft of the drive motor (81) is fixed with a drive shaft, the drive shaft is in transmission cooperation with the rack (842), the end of the drive shaft is sleeved with a cone wheel, and the cone wheel can mesh with the two cone wheel discs (852) at the same time.

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