Soil heavy metal pollution treatment device

Abstract

The invention belongs to the technical field of soil remediation, and particularly relates to a soil heavy metal pollution treatment device which comprises a vehicle body, a crushing box, a skid-mounted support, a feeding conveying belt, a reagent pump machine, a stirring pulping cylinder, a dewatering screen, a synergistic elution box, a first discharging conveying belt, a water conveying pipe, a waste water box, a mud-water separator and a second discharging conveying belt. The crushing box is of a hopper-shaped structure, a coarse screen and a hammer type crushing mechanism are arranged at the inlet end of the crushing box, and soil and water in the stirring pulping cylinder are fully mixed and stirred. The agent pump is connected with the synergistic elution box, the synergistic elution box is connected with the mud-water separator and the waste water tank, the mud-water separator sends out standard fine particle soil through a second discharging conveying belt and sends waste water containing heavy metal to the waste water tank through a water conveying pipe, and the waste water tank is connected with the stirring pulping cylinder through the pump. The modularized skid-mounted structure is mainly adopted, a soil leaching system is modularly integrated, then transportation is conducted through a truck, the occupied area is small, and the treatment efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, specifically relating to a device for treating heavy metal pollution in soil. Background Technology

[0002] Soil is a vital natural resource for human survival and development. However, with the acceleration of industrialization and urbanization, heavy metal pollution has become an increasingly prominent problem, posing a significant threat to the ecological environment and public health. Once soil is contaminated with heavy metals, it is not only difficult to remediate naturally, but it also continues to release pollutants for a long period, causing long-term effects on crops, water bodies, air, and human health. Therefore, strengthening the remediation of heavy metal pollution in soil has extremely important practical significance and far-reaching impact.

[0003] Existing technologies for remediating heavy metal pollution in soil mainly include leaching, phytoremediation, solidification / stabilization, soil barrier landfill, and cement kiln co-treatment. Among these, leaching is widely used due to its high treatment efficiency, especially effective for remediating soils with large particle sizes. Leaching includes in-situ soil leaching and ex-situ chemical leaching. In-situ soil leaching involves injecting leaching solution directly into the contaminated site and using physical-chemical reactions to migrate pollutants from the soil to groundwater or collection systems. While it offers advantages such as minimal construction disruption and rapid remediation, it requires a large construction area, and the flow path of the leaching solution in the soil is uncontrollable, easily leading to "preferred flow" and incomplete contact or migration of pollutants. Furthermore, leaching may cause pollutants to migrate underground, resulting in wider pollution spread, especially increasing the risk of groundwater contamination. Existing ex-situ chemical leaching involves excavating the contaminated soil and removing pollutants in a specialized off-site facility by adding chemical leaching agents (such as acids, alkalis, surfactants, or chelating agents). This requires long-distance transportation of the soil, which is far more expensive than in-situ methods. How to reduce soil transportation costs and improve efficiency while minimizing construction area and avoiding groundwater pollution has become an urgent problem to be solved. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, the purpose of this invention is to provide a soil heavy metal pollution remediation device that follows the ex-situ leaching concept, eliminating the need for large-scale on-site construction and reducing damage and pollution to the land. It primarily employs a modular skid-mounted structure, integrating the soil leaching system in a modular fashion, and then transporting it by truck. This results in a small footprint, high processing efficiency, and rapid, mobile deployment for on-site operation.

[0005] This invention adopts the following technical solution: a soil heavy metal pollution treatment device, comprising a vehicle body, a crushing box, a skid-mounted support, a feeding conveyor belt, a reagent pump, a mixing and slurrying cylinder, a dewatering screen, an efficiency-enhancing washing and desalination box, a first discharge conveyor belt, a water supply pipe, a wastewater tank, a mud-water separator, and a second discharge conveyor belt. The vehicle body is towable and movable. The crushing box, feeding conveyor belt, reagent pump, mixing and slurrying cylinder, dewatering screen, efficiency-enhancing washing and extraction box, first discharge conveyor belt, water pipe, wastewater tank, mud-water separator, and second discharge conveyor belt are sequentially installed on the vehicle body from the front to the rear via skid-mounted brackets. The crushing box has a bucket-shaped structure, with a coarse screen and hammer crusher at the inlet end to crush contaminated soil containing large solid waste into particles smaller than 50mm for subsequent processing. A feed conveyor belt is installed below the outlet at the bottom of the crushing box to transport the crushed soil to the inlet of the mixing and slurrying cylinder. The soil and water are thoroughly mixed inside the mixing drum. A dewatering screen is connected to the bottom outlet; the material that passes through the screen is large aggregate particles, while the material that passes through is a slurry enriched with heavy metals. The large aggregate particles are discharged through the outlet and conveyed by the first discharge conveyor belt; the slurry enriched with heavy metals enters the enhanced washing and dewatering tank. The reagent pump is connected to the enhancement washing tank, which is connected to the mud-water separator and the wastewater tank. The mud-water separator sends out the qualified fine-particle soil through the second discharge conveyor belt. The mud-water separator sends the wastewater containing heavy metals to the wastewater tank through the water supply pipe. The wastewater tank is connected to the mixing and slurry making cylinder through the pump.

[0006] According to another embodiment of the invention or any of the foregoing embodiments, the soil heavy metal pollution treatment device, wherein the enhanced elution box, through the structure of rotating blades and baffles, prolongs the reaction time and strengthens the physical contact between the soil and the agent, thereby increasing the migration rate of heavy metals.

[0007] According to another embodiment of the invention or any of the foregoing embodiments, the soil heavy metal pollution treatment device includes a reagent pump that delivers a leaching solution made of a citric acid solution in a preset ratio.

[0008] According to another embodiment of the invention or any of the foregoing embodiments, the soil heavy metal pollution treatment device uses a vibrating grading screen to separate clean soil particles larger than 2mm from the slurry and output them through a first discharge conveyor belt.

[0009] According to another embodiment of the invention or any of the foregoing embodiments, the soil heavy metal pollution treatment device is provided, wherein the mixing and slurry making cylinder adopts a double propeller blade and water spraying system.

[0010] According to another embodiment of the invention or any of the foregoing embodiments, the soil heavy metal pollution treatment device is wherein the feeding conveyor belt, the first discharge conveyor belt, and the second discharge conveyor belt are rubber belts and adopt a retractable and foldable design.

[0011] The beneficial effects of this invention are: 1. The soil heavy metal pollution remediation device disclosed in this invention integrates various functional modules on a skid-mounted support, which facilitates the overall loading, unloading and deployment of transport vehicles and is suitable for rapid switching of operations in multiple locations; the operation is carried out by a mobile transport vehicle, which reduces damage to the soil structure at the pollution site and prevents heavy metal migration; the entire process from crushing, pulping, chemical washing, separation to washing liquid recovery is integrated into one device, which has a small footprint and high efficiency. 2. The present invention has a compact structure and can operate in a cyclical manner: the reagent pump, water delivery pipe, and the efficiency-enhancing washing and desorption tank and wastewater tank form a closed-loop circulation system, which is energy-saving and environmentally friendly; it is suitable for various soil heavy metal pollution treatment scenarios such as industrial parks, mining areas, and construction land. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the principle of soil heavy metal pollution remediation upon which this invention is based; Figure 2 This is a side view of the soil heavy metal pollution treatment device of the present invention; Figure 3 for Figure 2 An enlarged schematic diagram of part A; Figure 4 This is a three-dimensional schematic diagram of the soil heavy metal pollution treatment device according to the present invention; In the diagram: 1. Vehicle body; 2. Crushing box; 3. Skid-mounted support; 4. Feed conveyor belt; 5. Chemical pump; 6. Mixing and slurrying cylinder; 7. Dewatering screen; 8. Enhanced washing and dewatering box; 9. First discharge conveyor belt; 10. Water supply pipe; 11. Wastewater tank; 12. Mud-water separator; 13. Second discharge conveyor belt. Detailed Implementation

[0013] 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.

[0014] like Figure 2 As shown, a soil heavy metal pollution remediation device includes a vehicle body 1, a crushing box 2, a skid-mounted support 3, a feeding conveyor belt 4, a reagent pump 5, a mixing and slurrying cylinder 6, a dewatering screen 7, an efficiency-enhancing washing and descaling box 8, a first discharge conveyor belt 9, a water supply pipe 10, a wastewater tank 11, a mud-water separator 12, and a second discharge conveyor belt 13. like Figure 2As shown, the vehicle body 1 is towable and movable. The crushing box 2, feeding conveyor belt 4, reagent pump 5, mixing and slurrying cylinder 6, dewatering screen 7, efficiency-enhancing washing and dewatering box 8, first discharge conveyor belt 9, water pipe 10, wastewater tank 11, mud-water separator 12, and second discharge conveyor belt 13 are sequentially installed on the vehicle body 1 from the front to the rear via skid-mounted brackets 3. like Figure 4 As shown, the crushing box 2 has a bucket-shaped structure, with a coarse screen and hammer crushing mechanism at the inlet end to crush contaminated soil containing large solid waste into particles smaller than 50mm for subsequent processing; a feed conveyor belt 4 is installed below the outlet at the bottom of the crushing box 2 to transport the crushed soil to the inlet of the mixing and slurrying cylinder 6. like Figure 2 , 3 As shown, the soil and water are thoroughly mixed in the mixing drum 6. The bottom outlet is connected to the dewatering screen 7. The material on the screen is large aggregate particles, and the material under the screen is slurry enriched with heavy metals. The large aggregate particles are discharged through the discharge port and conveyed by the first discharge conveyor belt 9. The slurry enriched with heavy metals enters the enhancement washing and dewatering box 8. The dewatering screen 7 adopts a vibrating grading screen to separate clean soil particles larger than 2mm from the slurry. The particles are then output through the first discharge conveyor belt 9. The mixing drum 6 adopts a double helical blade and water spray system.

[0015] like Figure 2 , 4 As shown, the reagent pump 5 is connected to the enhanced elution tank 8. The enhanced elution tank 8, through its rotating blades and baffle structure, extends the reaction time and enhances the physical contact between the soil and the reagent. The reagent pump 5 delivers a leaching solution made from a preset proportion of citric acid solution. The enhanced elution tank 8 is connected to the mud-water separator 12 and the wastewater tank 11. The mud-water separator 12 delivers qualified fine-particle soil through the second discharge conveyor belt 13. The mud-water separator 12 delivers heavy metal-containing wastewater to the wastewater tank 11 through the water pipe 10. The wastewater tank 11 is connected to the mixing and slurry-making cylinder 6 via a pump. The feed conveyor belt 4, the first discharge conveyor belt 9, and the second discharge conveyor belt 13 are rubber belts with a retractable and foldable design.

[0016] Working principle of the invention: like Figure 1 As shown, the soil heavy metal pollution treatment device provided by the present invention is based on the technical route of "ex-situ rinsing + modular skid-mounted", with physical crushing, chemical elution, solid-liquid separation and waste liquid recycling as the core processing chain. Relying on the skid-mounted modular integrated structure, it realizes rapid mobile treatment, deep decontamination and resource recycling of polluted soil.

[0017] During operation, the contaminated soil is first crushed and screened to reduce particle size and remove impurities, ensuring that the soil particle size is suitable for subsequent screening and washing processes. After being fed into the mixing and slurrying cylinder 6 by the feed conveyor belt 4, it falls onto the upper part of the dewatering screen 7. The material on the screen is large aggregate particles, and the material under the screen is slurry and fine sand. The large aggregate particles are discharged through the discharge port and transported by the first discharge conveyor belt 9.

[0018] Subsequently, the heavy metal-enriched slurry enters the enhanced elution tank 8, where chelating agents (such as EDTA, citric acid, etc.) and appropriate amounts of water are added via the reagent pump 5 to form a highly dispersed soil slurry. Under the action of spiral stirring and water spraying, heavy metals begin to desorb and dissolve from the surface and pores of soil particles into the liquid phase. To further extend the contact time between the reagent and the soil, mechanical stirring is used to enhance the reaction kinetics and improve the elution efficiency of heavy metals. After the reaction is completed, the slurry enters the mud-water separator for coarse particle screening and slurry concentration. Through the mud-water separator 12 (such as a horizontal screw centrifuge, settling tank, vacuum filter, etc.), the fine soil in the slurry is further separated from the waste liquid containing heavy metals, realizing the recovery of clean soil and the centralized collection of polluted liquid. The separated waste liquid enters the wastewater tank 11 through the water pipe 10, where it can be further treated using sedimentation, flocculation, activated carbon adsorption, or membrane separation technologies, and can be reused for mixing and slurry preparation in the stirring and slurry preparation tank 6, realizing closed-loop operation of the system.

[0019] The entire process is scheduled through a centralized control system, which enables automatic control and remote monitoring of parameters such as reagent dosage ratio, feed and discharge flow rate, and equipment start-up and shutdown, ensuring the safe, stable, and efficient operation of the system.

[0020] The soil heavy metal pollution remediation device provided by this invention mainly follows the concept of "ex-situ leaching + modular skid-mounted" to achieve efficient remediation of contaminated soil. Its working process is as follows: Step 1: Equipment Relocation and Deployment: The various modules of the device are integrated on a skid-mounted base and transported as a whole by a transport truck to the area near the contaminated soil. After positioning and leveling are completed using hydraulic outriggers or fixing devices, and the power supply, electrical control, and water supply pipelines are connected, the device can be put into operation.

[0021] Step 2: Polluted soil feeding and crushing pretreatment: Polluted soil is fed into the crushing box 2 at the front of the device by excavation equipment (such as grab bucket, loader). Large soil, bricks or lumps are crushed into soil particles with a diameter of less than 50mm to facilitate subsequent slurry mixing and reaction.

[0022] Step 3: Conveying and mixing the agent to make slurry: The crushed soil is fed into the mixing drum 6 through the feed conveyor belt 4. Inside the mixing drum, the soil and water are fully mixed under the action of the double propeller blades and the spray water to form a homogeneous slurry, creating good conditions for the leaching reaction.

[0023] Step 4: Enhanced Reaction – Synergistic Elution The mixed slurry flows into the dewatering screen 7, where relatively clean soil material with particles larger than 2mm is screened out and transported to the temporary storage area via the first discharge conveyor belt 9 for backfilling or secondary use. The heavy metal-enriched slurry enters the enhanced washing tank 8, while a pre-proportioned washing solution (such as EDTA, citric acid solution, etc.) is added to the slurry mixing cylinder by the reagent pump 5. The contact time between the reagent and the soil is further extended by a rotary agitator and baffles, enhancing the leaching effect of heavy metals and improving reagent utilization. In this step, pollutants are desorbed from the surface or pores of soil particles and enter the liquid phase.

[0024] Step 5: Mud-water separation—fine soil recycling The screened slurry is fed into a slurry separator 12, where fine soil particles are further separated from the heavy metal-containing wastewater using methods such as horizontal screw centrifugation, sedimentation + flocculation, or vacuum filtration. The separated fine soil particles are output via a second discharge conveyor belt 13; the remaining waste liquid enters the wastewater treatment system.

[0025] Step 6: Washing solution recovery and recycling Wastewater containing heavy metals is sent to wastewater tank 11 through water pipe 10. After purification by flocculation sedimentation, activated carbon adsorption and other methods, it can be partially reused in the mixing and pulping step of mixing and pulping drum 6, thus forming a closed-loop treatment system and significantly reducing water consumption and sewage discharge.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments are merely illustrative of the technical concept and characteristics of the present invention, intended to enable those skilled in the art to understand and implement the invention, and should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A soil heavy metal pollution remediation device, characterized in that: Includes vehicle body (1), crushing box (2), skid-mounted support (3), feed conveyor belt (4), reagent pump (5), mixing and slurrying cylinder (6), dewatering screen (7), efficiency-enhancing washing and dewatering box (8), first discharge conveyor belt (9), water supply pipe (10), wastewater tank (11), mud-water separator (12), and second discharge conveyor belt (13). The vehicle body (1) is towable and movable. The crushing box (2), feeding conveyor belt (4), reagent pump (5), mixing and slurry making cylinder (6), dewatering screen (7), efficiency washing and dewatering box (8), first discharge conveyor belt (9), water pipe (10), wastewater tank (11), mud-water separator (12), and second discharge conveyor belt (13) are installed on the vehicle body (1) from front to rear via skid-mounted brackets (3). The crushing box (2) has a bucket-shaped structure, with a coarse screen and hammer crushing mechanism at the inlet end to crush contaminated soil containing large solid waste into particles smaller than 50mm for subsequent processing; a feed conveyor belt (4) is installed below the outlet at the bottom of the crushing box (2) to transport the crushed soil to the inlet of the mixing and slurrying cylinder (6). The soil and water are thoroughly mixed in the mixing drum (6), and the bottom outlet is connected to a dewatering screen (7). The material on the screen is large aggregate particles, and the material under the screen is slurry enriched with heavy metals. The large aggregate particles are discharged through the discharge port and transported by the first discharge conveyor belt (9). The slurry enriched with heavy metals enters the enhancement washing and dewatering tank (8). The agent pump (5) is connected to the enhancement washing tank (8), which is connected to the mud-water separator (12) and the wastewater tank (11). The mud-water separator (12) sends out the qualified fine-particle soil through the second discharge conveyor belt (13). The mud-water separator (12) sends the heavy metal-containing wastewater to the wastewater tank (11) through the water pipe (10). The wastewater tank (11) is connected to the stirring and slurry making cylinder (6) through the pump.

2. The soil heavy metal pollution remediation device according to claim 1, characterized in that: The enhanced elution chamber (8) extends the reaction time and strengthens the physical contact between the soil and the agent through the construction of rotating blades and baffles, thereby increasing the migration rate of heavy metals.

3. The soil heavy metal pollution remediation device according to claim 1, characterized in that: The pharmaceutical pump (5) delivers a rinsing solution made from a citric acid solution in a preset ratio.

4. The soil heavy metal pollution remediation device according to claim 1, characterized in that: The dewatering screen (7) uses a vibrating grading screen to separate clean soil particles larger than 2mm from the slurry and output them through the first discharge conveyor belt (9).

5. The soil heavy metal pollution remediation device according to claim 1, characterized in that: The mixing and slurry making cylinder (6) adopts a double propeller blade and water spray system.

6. The soil heavy metal pollution remediation device according to claim 1, characterized in that: The feeding conveyor belt (4), the first discharge conveyor belt (9), and the second discharge conveyor belt (13) are rubber belts with a telescopic and foldable design.

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