A heavy metal contaminated soil pretreatment device beneficial to uniform mixing

Abstract

The application belongs to the technical field of soil pretreatment, and discloses a heavy metal contaminated soil pretreatment device facilitating uniform mixing, which comprises a mounting frame, a stirring chamber is fixedly connected to the middle of the mounting frame, a feeding conveyor belt is installed on one side of the stirring chamber, a discharging conveyor belt is installed on the other side of the stirring chamber, a lower hopper is fixedly connected to the side of the stirring chamber close to the top of the feeding conveyor belt, through the cooperation of the structures such as the back-to-back sleeve, the slide rod, the eccentric slide column and the chain, the synchronous reciprocating motion of the moving plate, the double-layer screen, the vibrating frame and the re-screening screen is facilitated, the driving source is fully utilized, the crushing, grinding, primary screening and re-screening processes are combined and distributed, the soil clods are made from large to small, different crushing tools are used in different stages, the crushing and screening efficiency is improved, the collapse of the precision cutter, the rolling of the cutter, the tearing and deformation of the screen are effectively avoided, the failure rate and the maintenance cost are greatly reduced, and the service life of the core precision parts is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of soil pretreatment technology, specifically a pretreatment device for heavy metal contaminated soil that facilitates uniform mixing. Background Technology

[0002] Heavy metal contaminated soil pretreatment equipment is specifically designed for the preliminary treatment of soil contaminated with heavy metals before remediation. These devices aim to prepare soil materials that meet the requirements for subsequent core remediation stages, such as stabilization, leaching, and bioremediation, through a series of physical or chemical methods. The main pretreatment process includes crushing and grinding, screening and separation, mixing and homogenization. First, large pieces of soil are crushed into smaller particles, then screened to remove large-diameter impurities such as stones and construction waste from the soil. Then, the remediation agent is brought into full and uniform contact with the contaminated soil particles to facilitate subsequent soil remediation work.

[0003] The prior art document CN119114204B discloses a soil sample pre-crushing treatment device for soil pollution detection, which relates to the field of soil sample crushing technology. It includes: a mounting frame; a crushing chamber rotatably mounted on the mounting frame; a stirring and crushing device rotatably mounted inside the crushing chamber; a grinding frame rotatably mounted inside the crushing chamber and grinding the soil sample during rotation; and multiple locking components arranged in a ring array fixed to the inner surface of the grinding frame. This invention uses the stirring and crushing device to crush the soil sample through rotation. Simultaneously, after crushing, it drives the grinding frame, a filter device, and the filter to rotate, adjusting the sample drop direction in the crushing chamber and adjusting the filtration fineness. This allows the filter to filter out easily ground soil lumps during crushing and to filter out finely ground soil samples that meet the requirements during grinding.

[0004] Although the above-mentioned device allows the filtration device to adjust the fineness of filtration, it mainly uses a mixing and crushing device for soil crushing, which is not suitable for the pretreatment of various types of soil. For example, when treating soil with a high stone content, it is easy to cause the precision blades to chip or roll, and the filter screen to tear or deform, reducing the service life of precision parts. Summary of the Invention

[0005] To address the problem mentioned in the background art that existing devices are difficult to apply to the pretreatment of various types of soil, the present invention provides a pretreatment device for heavy metal contaminated soil that facilitates uniform mixing.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a pretreatment device for heavy metal contaminated soil that facilitates uniform mixing, comprising a mounting frame, a mixing chamber fixedly connected to the middle of the mounting frame, a feeding conveyor belt installed on one side of the mixing chamber, a discharging conveyor belt installed on the other side of the mixing chamber, and a discharge hopper fixedly connected to the top of the feeding conveyor belt near the mixing chamber; further comprising: a crushing and screening mechanism connected to the feeding conveyor belt; and an automatic grinding mechanism located on the crushing and screening mechanism.

[0007] The crushing and screening mechanism first crushes large pieces of soil into small pieces, then screens them to remove impurities, and finally refines the soil through an automatic grinding mechanism. The crushing and screening mechanism includes a pretreatment box fixed above the feed conveyor belt.

[0008] The automatic grinding mechanism includes a fixed plate fixed to the middle of the pretreatment box. Several grinding grooves are evenly opened on the fixed plate. The grinding grooves are divided into two inverted conical designs, one wider at the top and one narrower at the bottom. A conical grinding column 1 is movably fitted on the lower side of each grinding groove. The top of the multiple conical grinding columns 1 is fixed to the conical grinding column 2 through connecting columns. The bottom of the multiple conical grinding columns 1 is rotatably connected to a vibration frame. The four corners of the vibration frame are also elastically connected to the corner plates through helical springs. The side walls of the vibration frame are also fixed with U-shaped sleeves.

[0009] Preferably, the crushing and screening mechanism further includes a feed hopper fixed to the top of the pretreatment box, the inner cavity of the feed hopper is rotatably connected to a guide plate, and the edge of the feed hopper is attached to the guide plate by a rubber baffle.

[0010] Preferably, a movable plate is slidably connected to the bottom of the guide plate, and movable crushing teeth are fixedly connected to the side wall of the movable plate. Fixed teeth are fixedly connected to the upper side of the inner cavity of the pretreatment box. An elastic telescopic rod and a movable pull rod are rotatably connected to the bottom edge of the movable plate, and both are rotatably connected to the pretreatment box through a support plate. Eccentric shafts are fixedly connected to both sides of the movable plate.

[0011] Preferably, a double-layer screen is slidably connected to the upper side of the middle part of the pretreatment box, and a secondary screen is slidably connected to the lower side. Multiple corner plates are fixed to the corners of the inner cavity of the pretreatment box. The double-layer screen and the secondary screen are elastically connected to the corner plates by helical springs. Several discharge troughs are provided on both sides of the pretreatment box.

[0012] Preferably, the side walls of the double-layer screen and the composite screen are both fixedly connected with U-shaped sleeves, and the sides of the U-shaped sleeves are both fixedly connected with sliding rods, and the sliding rods are slidably connected to the pretreatment box through limiting sleeves.

[0013] Preferably, the automatic grinding mechanism further includes a protective shell fixed to the side wall of the pretreatment box, a drive motor fixed to the side wall of the protective shell, a rotating shaft fixed to the output end of the drive motor, and four rotating shafts, each of which is meshed with a chain through gears.

[0014] Preferably, the rotating shaft mentioned above is fixedly connected to the eccentric shaft, and the remaining three rotating shafts are slidably connected to the U-shaped sleeve through eccentric sliding columns. Each rotating shaft has a sliding groove, and the eccentric sliding column is slidably connected to the sliding groove through a threaded rod, with the end of the threaded rod rotatably connected to the rotating shaft.

[0015] Preferably, the inner cavity of the second conical grinding column is movably connected to a telescopic top cap, which is fixed to the pretreatment box via a positioning rod. The inner cavity of the telescopic top cap is elastically connected to a corrugated groove column, the bottom of which is fixed to the inner surface of the bottom of the first conical grinding column. The lower end of the inner cavity of the telescopic top cap is fixed to a pressing slider, which is slidably connected to the groove of the corrugated groove column.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] This invention, through the combination of structures such as a spiral sleeve, sliding rod, eccentric sliding column, and chain, facilitates the synchronous reciprocating motion of the moving plate, double-layer screen, vibrating frame, and secondary screen. It makes full use of the drive source, effectively saves energy, and the crushing, grinding, primary screening, and secondary screening processes are interleaved and distributed, allowing soil clods to be graded from large to small using different crushing tools. This improves crushing and screening efficiency while effectively preventing chipping and curling of precision tools and tearing and deformation of the screen, significantly reducing failure rate and maintenance costs, and extending the service life of core precision components.

[0018] This invention achieves a graded grinding effect by combining a conical grinding column one, a conical grinding column two, and a corrugated groove column, thus grinding the soil into a finer particle. During the grinding process, the soil enters the grinding groove on the fixed plate. Due to the design of the two inverted conical grooves, which are wider at the top and narrower at the bottom, the soil first passes through the wider gap at the top for grinding and then reaches the narrower gap at the bottom for further graded grinding. Under the fixing and limiting action of the positioning rod on the telescopic cap, the telescopic cap located in the inner cavity of the conical grinding column two is squeezed and slid within the corrugated groove column by the squeezing slider, causing the conical grinding column one and the conical grinding column two to rotate intermittently and synchronously, thereby increasing the crushing and grinding effect, grinding the soil into a finer particle, and preventing the soil from clogging the grinding groove.

[0019] This invention improves screening efficiency by using a combination of double-layer and triple-layer screens. Both the double-layer and triple-layer screens are inclined relative to the pretreatment box, allowing impurities to be discharged smoothly along the slope after screening. The two layers of the double-layer screen form an angle, with opposite discharge directions to prevent mixing. After screening in the upper layer, the soil is screened again through the lower layer with denser mesh to prevent large soil particles from affecting the next grinding process. The triple-layer screen removes impurities from the soil after secondary crushing, leaving fine soil that falls onto the feed conveyor belt. The position of the eccentric sliding column in the rotating shaft can also be adjusted, i.e., the eccentric displacement can be adjusted, thereby regulating the screen amplitude and changing the screening rate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram showing the structural fit between the pretreatment box and the feed hopper of the present invention;

[0022] Figure 3 This is a rear-view stereoscopic structural diagram of the present invention;

[0023] Figure 4 This is a top view of the structure of the present invention;

[0024] Figure 5 This is a schematic diagram showing the structural fit between the double-layer screen and the pretreatment box of the present invention;

[0025] Figure 6 For the present invention Figure 5 A magnified view of the structure at point A in the middle;

[0026] Figure 7 For the present invention Figure 5 A magnified schematic diagram of the structure at point B in the middle;

[0027] Figure 8 This is a schematic diagram showing the structural fit between the conical grinding column and the vibration frame of the present invention;

[0028] Figure 9 This is a schematic diagram showing the structural fit between the vibration frame and the spiral sleeve of the present invention;

[0029] Figure 10 This is a schematic diagram showing the structural fit between the rotating shaft and the eccentric sliding column of the present invention;

[0030] Figure 11 This is a schematic diagram showing the structural fit between the threaded rod and the rotating shaft of the present invention;

[0031] Figure 12 This is a schematic diagram showing the structural fit between the extrusion slider and the corrugated column of the present invention.

[0032] In the picture:

[0033] 1. Mounting frame; 2. Crushing and screening mechanism; 201. Pre-treatment box; 202. Feed hopper; 203. Guide plate; 204. Rubber baffle; 205. Fixed teeth; 206. Moving crushing teeth; 207. Discharge chute; 208. Moving plate; 209. Double-layer screen; 2010. Complementary screen; 2011. Helical spring; 2012. Angle plate; 2013. Elastic telescopic rod; 2014. Movable tie rod; 2015. Eccentric shaft; 2016. Slide rod; 2017. Limiting sleeve; 2018. Return sleeve; 3. Automatic grinding Mechanism; 301, Protective shell; 302, Chain; 303, Rotating shaft; 304, Gear; 305, Drive motor; 306, Vibrating frame; 307, Conical grinding column one; 308, Fixing plate; 309, Grinding groove; 3010, Telescopic top cap; 3011, Slide groove; 3012, Eccentric sliding column; 3013, Threaded rod; 3014, Extrusion slider; 3015, Corrugated groove column; 3016, Conical grinding column two; 3017, Positioning rod; 4, Feed conveyor belt; 5, Discharge hopper; 6, Mixing chamber; 7, Discharge conveyor belt. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figures 1 to 12 As shown, the present invention provides a pretreatment device for heavy metal contaminated soil that facilitates uniform mixing. It includes a mounting frame 1, a mixing chamber 6 fixedly connected to the middle of the mounting frame 1, a feeding conveyor belt 4 installed on one side of the mixing chamber 6, a discharging conveyor belt 7 installed on the other side of the mixing chamber 6, and a discharge hopper 5 fixedly connected to the top of the feeding conveyor belt 4 near the mixing chamber 6. The device also includes: a crushing and screening mechanism 2 connected to the feeding conveyor belt 4; and an automatic grinding mechanism 3 located on the crushing and screening mechanism 2.

[0036] Among them, the crushing and screening mechanism 2 first crushes large soil pieces into small soil pieces, and after screening to remove impurities, the soil is further refined by the automatic grinding mechanism 3. The crushing and screening mechanism 2 includes a pretreatment box 201 fixed above the feed conveyor belt 4.

[0037] The automatic grinding mechanism 3 includes a fixed plate 308 fixed to the middle of the pretreatment box 201. Several grinding grooves 309 are evenly provided on the fixed plate 308. The grinding grooves 309 are divided into two inverted conical designs with a wider top and a narrower bottom. Conical grinding columns 307 are movably fitted on the lower side of each grinding groove 309. Conical grinding columns 3016 are fixed to the top of the multiple conical grinding columns 307 through connecting columns. The bottom of the multiple conical grinding columns 307 are rotatably connected to a vibration frame 306. The four corners of the vibration frame 306 are also elastically connected to the corner plates 2012 through helical springs 2011. The side walls of the vibration frame 306 are also fixed with U-shaped sleeves 2018.

[0038] The above scheme is adopted as follows: First, the soil clods are put into the crushing and screening mechanism 2. After primary crushing, primary screening, secondary crushing and grinding and re-screening, the fine soil is left to fall onto the feed conveyor belt 4. After continuous feeding of the medicine by the medicine hopper 5, it is then transferred to the mixing chamber 6 for thorough mixing. Finally, it is conveyed out through the discharge conveyor belt 7 to complete the pretreatment, so as to facilitate the subsequent soil remediation.

[0039] like Figures 2 to 6 As shown, the crushing and screening mechanism 2 also includes a feed hopper 202 fixed to the top of the pretreatment box 201. A guide plate 203 is rotatably connected to the inner cavity of the feed hopper 202. The edge of the feed hopper 202 is connected to the guide plate 203 by a rubber baffle 204. A movable plate 208 is slidably connected to the bottom of the guide plate 203. A movable crushing tooth 206 is fixed to the side wall of the movable plate 208. A fixed tooth 205 is fixed to the upper side of the inner cavity of the pretreatment box 201. An elastic telescopic rod 2013 and a movable pull rod 2014 are rotatably connected to the bottom edge of the movable plate 208, and both are rotatably connected to the pretreatment box 201 by a support plate. An eccentric shaft 2015 is fixed to both sides of the movable plate 208.

[0040] like Figures 5 to 9 As shown, a double-layer screen 209 is slidably connected to the upper side of the middle part of the pretreatment box 201, and a secondary screen 2010 is slidably connected to the lower side. Multiple corner plates 2012 are fixedly connected to the corners of the inner cavity of the pretreatment box 201. The double-layer screen 209 and the secondary screen 2010 are elastically connected to the corner plates 2012 through helical springs 2011. Several discharge troughs 207 are opened on both sides of the pretreatment box 201. The side walls of the double-layer screen 209 and the secondary screen 2010 are fixedly connected to the U-shaped sleeves 2018. Slide rods 2016 are fixedly connected to both sides of the U-shaped sleeves 2018. The slide rods 2016 are slidably connected to the pretreatment box 201 through limiting sleeves 2017.

[0041] The above scheme employs a double-layer screen 209 and a secondary screen 2010, both inclined relative to the pretreatment chamber 201. This allows impurities to be discharged smoothly along the slope after screening, and the two layers of the double-layer screen 209 form an angle, with opposite discharge directions. The mesh sizes of the upper and lower layers of the double-layer screen 209 and the secondary screen 2010 progressively decrease to ensure thorough screening. When small clods of soil fall onto the double-layer screen 209, they are first screened on the first layer, while larger particles such as stones are discharged from the discharge chute 207. Workers can then re-feed the clods and impurities based on their distribution, continuing the crushing cycle. After screening in the upper layer, the clods are screened again through the denser mesh of the lower layer to prevent larger particles from affecting the next grinding step.

[0042] like Figures 8 to 11 As shown, the automatic grinding mechanism 3 also includes a protective shell 301 fixed to the side wall of the pretreatment box 201. A drive motor 305 is fixed to the side wall of the protective shell 301. A rotating shaft 303 is fixed to the output end of the drive motor 305. There are four rotating shafts 303, and each of the four rotating shafts 303 is meshed with a chain 302 through a gear 304.

[0043] like Figures 8 to 12 As shown, the upper rotating shaft 303 is fixedly connected to the eccentric shaft 2015, and the remaining three rotating shafts 303 are slidably connected to the U-shaped sleeve 2018 through eccentric sliding columns 3012. Each rotating shaft 303 has a sliding groove 3011 inside, and the eccentric sliding column 3012 is slidably connected to the sliding groove 3011 through a threaded rod 3013. The end of the threaded rod 3013 is rotatably connected to the rotating shaft 303. The inner cavity of the conical grinding column 3016 is movably connected to... Telescopic cap 3010 is fixed to pretreatment box 201 via positioning rod 3017. The inner cavity of telescopic cap 3010 is elastically connected to a wave groove column 3015. The bottom of wave groove column 3015 is fixed to the bottom inner surface of conical grinding column 307. The lower end of the inner cavity of telescopic cap 3010 is fixed to a pressing slider 3014, and the pressing slider 3014 is slidably connected in the groove of wave groove column 3015.

[0044] The above-mentioned scheme employs an open design on the upper side of the grinding trough 309 to facilitate the collection of soil blocks and prevent accumulation. After primary screening, the soil blocks enter the grinding trough 309 on the fixed plate 308. Due to the reciprocating movement of the vibrating frame 306, the first conical grinding column 307 drives the second conical grinding column 3016 to repeatedly approach the upper and lower parts of the grinding trough 309, further crushing the falling soil blocks. The two inverted conical grooves of the grinding trough 309 are wider at the top and narrower at the bottom, resulting in a larger gap between the second conical grinding column 3016 and the grinding trough 309 than the gap between the first conical grinding column 307 and the grinding trough 309. Therefore, the soil blocks are first ground through the wider gap at the top and then through the narrower gap at the bottom, achieving a further graded grinding effect.

[0045] Working principle and usage process of this invention:

[0046] First, soil clods are fed into the feed hopper 202. The drive motor 305 is started, which drives the eccentric shaft 2015 to rotate via the rotating shaft 303. This, in turn, causes the moving plate 208 to reciprocate in a circular motion. The elastic telescopic rod 2013 and the movable pull rod 2014 limit and support the moving plate 208, causing the moving crushing teeth 206 to continuously approach the fixed teeth 205. This is equivalent to continuous vibration and compression, breaking the large soil clods into smaller ones. Furthermore, during the movement of the moving plate 208, the guide plate 203 also rotates slightly, loosening the accumulated soil clods downwards to facilitate continuous feeding.

[0047] Driven by the chain 302, all four shafts 303 rotate via gears 304. This causes the eccentric sliding column 3012 on the shafts 303 to continuously slide and compress the loop sleeve 2018. Since the loop sleeve 2018 is limited within the limiting sleeve 2017 by the sliding rod 2016, it can reciprocate axially along the sliding rod 2016. The three loop sleeves 2018 synchronously drive the double-layer screen 209, the vibrating frame 306, and the secondary screen 2010, causing them to move up and down. The spiral spring 2011 and the angle plate 2012 assist in vibration and support. When small clods of earth fall onto the double-layer screen 209, they are first screened on the first layer. Larger particles such as stones are discharged from the discharge chute 207. Workers can then re-feed the clods and impurities according to their distribution, continuing the crushing cycle. After the upper layer is screened, it is screened again through a lower layer with a denser mesh to prevent the soil clods from being too large and affecting the next grinding process.

[0048] Next, the soil blocks after primary screening enter the grinding trough 309 on the fixed plate 308. As the vibrating frame 306 moves up and down reciprocally, the first conical grinding column 307 drives the second conical grinding column 3016 to reciprocate close to the upper and lower parts of the grinding trough 309, further crushing the falling soil blocks. The two inverted conical grooves of the grinding trough 309 are wider at the top and narrower at the bottom, making the gap between the second conical grinding column 3016 and the grinding trough 309 larger than the gap between the first conical grinding column 307 and the grinding trough 309. Therefore, the soil blocks are first ground through the wider gap at the top and then ground through the narrower gap at the bottom, achieving a further graded grinding effect. Furthermore, under the fixing and limiting effect of the positioning rod 3017 on the telescopic cap 3010, when the conical grinding column one 307 and the conical grinding column two 3016 vibrate continuously, the telescopic cap 3010 located in the inner cavity of the conical grinding column two 3016 is squeezed and slid within the corrugated column 3015 by the squeezing slider 3014, and reset by the elastic force of the internal spring. The conical grinding column one 307 is rotatably connected to the vibrating frame 306. Therefore, driven by the corrugated column 3015, the conical grinding column one 307 and the conical grinding column two 3016 can rotate intermittently synchronously, thereby increasing the crushing and grinding effect, grinding the soil into finer particles, and preventing soil particles from clogging the grinding groove 309. In addition, according to the soil requirements, the threaded rod 3013 can be rotated in advance to adjust the position of the eccentric sliding column 3012 in the rotating shaft 303, that is, to adjust the eccentric displacement, thereby achieving the function of adjusting the amplitude, changing the screening rate and the size of the grinding particles;

[0049] The ground soil clods are then passed through a continuously vibrating screen 2010 to further remove stones and other impurities. Finally, the fine soil falls onto the feed conveyor belt 4, where it is continuously fed with chemicals through the chemical feeding hopper 5. It is then transported to the mixing chamber 6 for thorough mixing and finally conveyed out through the discharge conveyor belt 7, completing the pretreatment to facilitate subsequent soil remediation.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pretreatment device for heavy metal contaminated soil that facilitates uniform mixing, comprising a mounting frame (1), wherein a mixing chamber (6) is fixedly connected to the middle of the mounting frame (1), a feeding conveyor belt (4) is installed on one side of the mixing chamber (6), and a discharging conveyor belt (7) is installed on the other side of the mixing chamber (6), wherein a discharging hopper (5) is fixedly connected to the top of the feeding conveyor belt (4) near the mixing chamber (6), characterized in that: Also includes: Crushing and screening mechanism (2), wherein the crushing and screening mechanism (2) is connected to the feeding conveyor belt (4); An automatic grinding mechanism (3) is located on the crushing and screening mechanism (2); The crushing and screening mechanism (2) first crushes large soil pieces into small soil pieces, then screens them to remove impurities and then refines the soil through an automatic grinding mechanism (3). The crushing and screening mechanism (2) includes a pretreatment box (201) fixed above the feed conveyor belt (4). The automatic grinding mechanism (3) includes a fixed plate (308) fixed to the middle of the pretreatment box (201). Several grinding grooves (309) are evenly provided on the fixed plate (308). Conical grinding columns (307) are movably fitted inside the grinding grooves (309). The bottoms of the multiple conical grinding columns (307) are rotatably connected to a vibrating frame (306). The four corners of the vibrating frame (306) are also elastically connected to the corner plates (2012) by helical springs (2011). The side walls of the vibrating frame (306) are also fixed with U-shaped sleeves (2018). The automatic grinding mechanism (3) also includes a protective shell (301) fixed to the side wall of the pretreatment box (201). A drive motor (305) is fixed to the side wall of the protective shell (301). A rotating shaft (303) is fixed to the output end of the drive motor (305). There are four rotating shafts (303). Each of the four rotating shafts (303) is meshed with a chain (302) through a gear (304). The rotating shaft (303) mentioned above is fixedly connected to the eccentric shaft (2015). The remaining three rotating shafts (303) are slidably connected to the spiral sleeve (2018) through the eccentric sliding column (3012). Each rotating shaft (303) has a sliding groove (3011). The eccentric sliding column (3012) is slidably connected to the sliding groove (3011) through the threaded rod (3013). The end of the threaded rod (3013) is rotatably connected to the rotating shaft (303). The inner cavity of the conical grinding column (307) is movably connected to a telescopic top cap (3010), and the inner cavity of the telescopic top cap (3010) is elastically connected to a wave groove column (3015). The bottom of the wave groove column (3015) is fixed to the bottom inner surface of the conical grinding column (307). The lower end of the inner cavity of the telescopic top cap (3010) is fixed to a pressing slider (3014), and the pressing slider (3014) is slidably connected to the groove of the wave groove column (3015).

2. The heavy metal contaminated soil pretreatment device for uniform mixing according to claim 1, characterized in that: The crushing and screening mechanism (2) also includes a feed hopper (202) fixed to the top of the pretreatment box (201). The inner cavity of the feed hopper (202) is rotatably connected to a guide plate (203), and the edge of the feed hopper (202) overlaps the guide plate (203) through a rubber baffle (204).

3. The heavy metal contaminated soil pretreatment device for uniform mixing according to claim 2, characterized in that: The bottom of the guide plate (203) is slidably connected to a movable plate (208), and the side wall of the movable plate (208) is fixedly connected to a movable crushing tooth (206). The upper side of the inner cavity of the pretreatment box (201) is fixedly connected to a fixed tooth (205). The bottom edge of the movable plate (208) is rotatably connected to an elastic telescopic rod (2013) and a movable pull rod (2014), and both are rotatably connected to the pretreatment box (201) through a support plate. Eccentric shafts (2015) are fixedly connected to both sides of the movable plate (208).

4. The heavy metal contaminated soil pretreatment device for uniform mixing according to claim 3, characterized in that: The pretreatment box (201) is slidably connected to a double-layer screen (209) on the upper side of the middle part and to a double screen (2010) on the lower side. Multiple corner plates (2012) are fixed to the corners of the inner cavity of the pretreatment box (201). The double-layer screen (209) and the double screen (2010) are elastically connected to the corner plates (2012) by a helical spring (2011). Several discharge troughs (207) are opened on both sides of the pretreatment box (201).

5. The heavy metal contaminated soil pretreatment device for uniform mixing according to claim 4, characterized in that: The side walls of the double-layer screen (209) and the composite screen (2010) are both fixed with a spiral sleeve (2018). The spiral sleeve (2018) is fixed with a sliding rod (2016) on both sides. The sliding rod (2016) is slidably connected to the pretreatment box (201) through a limiting sleeve (2017).

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