Heavy metal contaminated soil cleaning and heavy metal recycling device and working method thereof

Abstract

The invention discloses a heavy metal contaminated soil cleaning and heavy metal recycling device and a working method thereof, and relates to the technical field of heavy metal contaminated soil cleaning and heavy metal recycling. A first conductivity sensor is arranged, the first conductivity of the wastewater generated by the secondary cleaning tank is detected, a processor is arranged, whether the first conductivity is larger than or equal to a first preset value or not is judged, if yes, the secondary cleaning tank is controlled to work again till the first conductivity is smaller than the first preset value, and the secondary cleaning tank works again; and a heavy metal recycling part is arranged, and heavy metal in the wastewater is recycled. The effectiveness of soil cleaning is guaranteed in a repeated cleaning mode, meanwhile, the heavy metal recycling process can be completed, waste of heavy metal is avoided, and resource reutilization is further achieved.

Description

Technical Field

[0001] The present application relates to the technical field of heavy metal contaminated soil cleaning and heavy metal recovery, and in particular to a heavy metal contaminated soil cleaning and heavy metal recovery device and a working method thereof. Background Art

[0002] With the rapid development of modern industry, the problem of heavy metal contamination in soil has become increasingly prominent. Heavy metals in soil cannot be decomposed or degraded by microorganisms, gradually accumulate in the soil, and are transmitted and accumulated to the human body through the food chain, seriously endangering human health. Therefore, the removal of heavy metals in soil is of great practical significance.

[0003] Soil cleaning is an effective means of removing heavy metals from heavy metal-contaminated soil. Traditional cleaning devices cannot guarantee the effectiveness of soil cleaning. Traditional cleaning devices can only complete soil cleaning. At this time, the heavy metals removed by cleaning will be directly discharged, causing waste. In comparison, recycling them is a more economical and effective option. Summary of the invention

[0004] The purpose of the present application is to provide a heavy metal contaminated soil cleaning and heavy metal recovery device and a working method thereof, which can ensure the effectiveness of soil cleaning and can recover heavy metals.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a device for cleaning heavy metal contaminated soil and recovering heavy metals, the device for cleaning heavy metal contaminated soil and recovering heavy metals comprising:

[0007] A primary cleaning tank is used to add a surfactant solution to the heavy metal contaminated soil and stir the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater;

[0008] A secondary cleaning tank connected to the primary cleaning tank, used to add clean water to the initially cleaned soil, and to stir the initially cleaned soil and the clean water to produce cleaned soil and wastewater;

[0009] A first conductivity sensor, installed at the drain outlet of the secondary cleaning tank, for detecting a first conductivity of wastewater generated by the secondary cleaning tank;

[0010] a processor, which is in communication connection with the first conductivity sensor, and is used to determine whether the first conductivity is greater than or equal to a first preset value, and if so, control the secondary cleaning box to work again until the first conductivity is less than the first preset value, at which time the cleaned soil produced by the secondary cleaning box is clean soil after heavy metals are removed;

[0011] The heavy metal recovery component is used to treat the wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank to recover the heavy metals in the wastewater.

[0012] In some embodiments, the heavy metal contaminated soil cleaning and heavy metal recovery device further comprises:

[0013] The soil screening machine is used to screen the original heavy metal contaminated soil obtained by mining to obtain heavy metal contaminated soil without sand, gravel and large impurities.

[0014] In some embodiments, the heavy metal contaminated soil cleaning and heavy metal recovery device further comprises:

[0015] A surfactant dosing box, used for storing surfactant solution;

[0016] Water storage tanks for storing clean water;

[0017] The primary cleaning tank is connected to the surfactant dosing tank pipeline; the primary cleaning tank includes a primary drum and a plurality of dosing nozzles located inside the primary drum, and all the dosing nozzles are connected to the surfactant dosing tank pipeline; the primary drum is filled with heavy metal contaminated soil, the dosing nozzles are used to spray the surfactant solution to add the surfactant solution to the heavy metal contaminated soil, and the primary drum is used to rotate to stir the heavy metal contaminated soil and the surfactant solution to produce soil and wastewater after preliminary cleaning;

[0018] The secondary cleaning tank is connected to the water tank pipeline; the secondary cleaning tank includes a secondary drum and a plurality of cleaning nozzles located inside the secondary drum, and all the cleaning nozzles are connected to the water tank pipeline; the secondary drum is filled with preliminarily cleaned soil, the cleaning nozzles are used to spray clean water to add clean water to the preliminarily cleaned soil, the secondary drum is used to rotate to stir the preliminarily cleaned soil and the clean water, and the preliminarily cleaned soil is washed with the clean water to generate cleaned soil and wastewater.

[0019] In some embodiments, the heavy metal contaminated soil cleaning and heavy metal recovery device further comprises:

[0020] A wastewater tank connected to the primary cleaning tank and the secondary cleaning tank, used to store wastewater generated by the primary cleaning tank and wastewater generated by the secondary cleaning tank to obtain mixed wastewater;

[0021] A liquid level sensor, installed in the wastewater tank, for detecting the liquid level of the mixed wastewater in the wastewater tank;

[0022] A second conductivity sensor is installed at the bottom of the wastewater tank and is used to detect a second conductivity of the mixed wastewater in the wastewater tank;

[0023] The processor is respectively connected to the liquid level sensor and the second conductivity sensor for communication, and is used to determine whether the liquid level has reached a preset level. If so, it is determined whether the second conductivity is less than a second preset value. If so, the mixed wastewater in the wastewater tank is used as clean water, and the wastewater tank is used to provide clean water to the secondary cleaning tank.

[0024] In some embodiments, the heavy metal recovery component comprises:

[0025] A filter, used for filtering the mixed wastewater in the wastewater tank to obtain filtered wastewater;

[0026] A heavy metal recovery device is connected to the filter and the reverse osmosis device, and is used to determine whether the third conductivity of the influent of the heavy metal recovery device is greater than or equal to a third preset value. If so, the influent of the heavy metal recovery device is electrochemically precipitated using electrodes to recover heavy metals from the influent of the heavy metal recovery device to obtain recovered heavy metals and wastewater to be discharged; if not, the influent of the heavy metal recovery device is transported to the reverse osmosis device; wherein the influent of the heavy metal recovery device is filtered wastewater or a mixture of filtered wastewater and concentrated water;

[0027] The reverse osmosis device is connected to the heavy metal recovery device and is used to perform reverse osmosis treatment on the influent water of the heavy metal recovery device to generate concentrated water and produced water, and transport the concentrated water to the heavy metal recovery device.

[0028] In some embodiments, the filter comprises a paper filter and a membrane filter connected in sequence;

[0029] The paper filter is used to filter the mixed wastewater to separate the solid and liquid and obtain the initially filtered wastewater;

[0030] The membrane filter is used to filter the wastewater after preliminary filtration to perform solid-liquid separation to obtain filtered wastewater.

[0031] In some embodiments, the heavy metal recovery device comprises:

[0032] Electrochemical reaction cell, water inlet equipped with heavy metal recovery device;

[0033] The electrode is installed inside the electrochemical reaction cell and is used to electrochemically precipitate the influent of the heavy metal recovery device, recover the heavy metals from the influent of the heavy metal recovery device, and obtain the recovered heavy metals and wastewater to be discharged;

[0034] A third conductivity sensor, installed inside the electrochemical reaction cell, for detecting a third conductivity of the influent water of the heavy metal recovery device;

[0035] a processor, which is in communication with the third conductivity sensor and the power supply, and is used to determine whether the third conductivity of the influent water of the heavy metal recovery device is greater than or equal to a third preset value, and if so, control the power supply to operate;

[0036] A power source is electrically connected to the electrode and is used to supply power to the electrode.

[0037] In some embodiments, the reverse osmosis device is further connected to a water storage tank for delivering produced water to the water storage tank.

[0038] In some embodiments, the processor is further configured to deliver the mixed wastewater to the filter when the second conductivity is greater than or equal to a second preset value.

[0039] In a second aspect, the present application provides a method for cleaning heavy metal contaminated soil and recovering heavy metals, which is applied to any one of the above-mentioned heavy metal contaminated soil cleaning and heavy metal recovery devices, and the heavy metal contaminated soil cleaning and heavy metal recovery method comprises:

[0040] Controlling the operation of the primary cleaning tank to add a surfactant solution to the heavy metal contaminated soil, and stirring the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater;

[0041] Controlling the operation of the secondary cleaning tank to add clean water to the initially cleaned soil, and to stir the initially cleaned soil and the clean water to produce cleaned soil and waste water;

[0042] obtaining a first conductivity of wastewater generated by the secondary cleaning tank;

[0043] Determining whether the first conductivity is greater than or equal to a first preset value;

[0044] If yes, the cleaned soil is used as the primary cleaned soil and the process returns to the step of "controlling the operation of the secondary cleaning box";

[0045] If not, the cleaned soil produced by the secondary cleaning tank is used as the clean soil after heavy metal removal;

[0046] The wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank are treated to recover the heavy metals in the wastewater.

[0047] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0048] The present application provides a heavy metal contaminated soil cleaning and heavy metal recovery device and a working method thereof, comprising: a primary cleaning tank, used to add a surfactant solution to the heavy metal contaminated soil, and stir the heavy metal contaminated soil and the surfactant solution to produce preliminary cleaned soil and wastewater; a secondary cleaning tank, used to add clean water to the preliminary cleaned soil, and stir the preliminary cleaned soil and the clean water to produce cleaned soil and wastewater; a first conductivity sensor, used to detect a first conductivity of the wastewater produced by the secondary cleaning tank; a processor, used to determine whether the first conductivity is greater than or equal to a first preset value, and if so, control the secondary cleaning tank to work again until the first conductivity is less than the first preset value, at which time the cleaned soil produced by the secondary cleaning tank is clean soil after heavy metals are removed. The present application introduces a first conductivity sensor and a processor, and can judge whether the heavy metal contaminated soil has been effectively cleaned by the first conductivity of the wastewater discharged after cleaning with clean water. When the first conductivity is less than the first preset value, it means that the heavy metal contaminated soil has been effectively cleaned. At this time, the cleaned soil obtained by cleaning with clean water is used as the clean soil after removing heavy metals, and the effectiveness of soil cleaning can be ensured by repeated cleaning. In addition, the present application also provides a heavy metal recovery component for treating the wastewater generated by the first cleaning tank and the wastewater generated by the second cleaning tank to recover the heavy metals in the wastewater, thereby completing the heavy metal recovery process, avoiding the waste of heavy metals, and further realizing resource reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 This is a schematic structural diagram of a heavy metal contaminated soil cleaning and heavy metal recovery device provided in Example 1 of the present application.

[0051] Figure 2 This is a schematic diagram of the structure of the soil cleaning and wastewater recovery components provided in Example 1 of the present application.

[0052] Figure 3 This is a schematic diagram of the structure of the soil screening machine provided in Example 1 of the present application.

[0053] Figure 4 This is a schematic diagram of the structure of the primary cleaning box provided in Example 1 of the present application.

[0054] Figure 5This is a schematic diagram of the structure of the secondary cleaning box provided in Example 1 of the present application.

[0055] Figure 6 This is a schematic diagram of the working logic of the soil cleaning and wastewater recovery components provided in Example 1 of the present application.

[0056] Figure 7 This is a schematic diagram of the structure of the heavy metal recovery component provided in Example 1 of the present application.

[0057] Figure 8 This is a schematic diagram of the working logic of the heavy metal recovery component provided in Example 1 of the present application.

[0058] Reference numerals:

[0059] 1-soil screen; 2-surfactant dosing box; 3-water storage tank; 4-primary cleaning tank; 5-secondary cleaning tank; 6-first conductivity sensor; 7-soil storage tank; 8-wastewater tank; 9-second conductivity sensor; 10-gauze; 11-primary roller; 12-dosing nozzle; 13-secondary roller; 14-cleaning nozzle; 15-filter; 16-vacuum pump; 17-electrochemical reaction cell; 18-electrode; 19-third conductivity sensor; 20-power supply; 21-high pressure pump; 22-reverse osmosis device. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] Example 1

[0062] This embodiment provides a device for cleaning heavy metal contaminated soil and recovering heavy metals, and the device for cleaning heavy metal contaminated soil and recovering heavy metals comprises:

[0063] The primary cleaning tank is used to add a surfactant solution to the heavy metal contaminated soil and stir the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater.

[0064] The secondary cleaning tank is connected to the primary cleaning tank and is used for adding clean water to the soil after preliminary cleaning and stirring the soil after preliminary cleaning and the clean water to generate cleaned soil and waste water.

[0065] The first conductivity sensor is installed at the drain outlet of the secondary cleaning tank and is used to detect the first conductivity of the wastewater generated by the secondary cleaning tank.

[0066] The processor is connected to the first conductivity sensor for determining whether the first conductivity is greater than or equal to a first preset value. If so, the secondary cleaning box is controlled to operate again until the first conductivity is less than the first preset value. At this time, the cleaned soil produced by the secondary cleaning box is clean soil after heavy metals are removed.

[0067] The heavy metal recovery component is used to treat the wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank to recover the heavy metals in the wastewater.

[0068] This embodiment is designed with a first conductivity sensor to detect the first conductivity of the wastewater generated by the secondary cleaning tank, and performs cleaning again when the first conductivity is greater than or equal to the first preset value until the first conductivity is less than the first preset value, thereby ensuring the effectiveness of soil cleaning. This embodiment is designed with a heavy metal recovery component to recover heavy metals in wastewater to avoid waste of heavy metals.

[0069] The heavy metal contaminated soil cleaning and heavy metal recovery device provided in this embodiment includes soil cleaning and wastewater recovery components, such as Figure 1 and Figure 2 As shown, specifically including:

[0070] (1) Soil Screening Machine

[0071] The soil screening machine 1 is used to screen the original heavy metal contaminated soil obtained by mining to obtain the heavy metal contaminated soil without sand, gravel and large impurities.

[0072] like Figure 3 As shown, the soil screening machine 1 is divided into two layers, the upper and lower layers are separated by a mesh 10 in the middle, and the original heavy metal contaminated soil obtained by mining is directly introduced into the upper layer of the soil screening machine 1. The soil screening machine 1 screens the original heavy metal contaminated soil by vibration, and the vibration can break up the large pieces of original heavy metal contaminated soil, and make the small particles therein pass through the mesh 10 and enter the lower layer. The small particles entering the lower layer are the heavy metal contaminated soil, which can be subsequently transported to the primary cleaning box 4 by the crawler, and the large plant debris, stones and large particles left on the upper layer of the soil screening machine 1 will be discarded. Through the screening process of the soil screening machine 1, it is ensured that the subsequent cleaning process is more effective.

[0073] (2) Surfactant dosing box

[0074] The surfactant dosing box 2 is used to store surfactant solution. The surfactant solution refers to a solution composed of surfactant and water. The surfactant refers to a substance with fixed hydrophilic and lipophilic groups, which can be arranged in a directional manner on the surface of the solution and can significantly reduce the surface tension.

[0075] (3) Water tank

[0076] The water storage tank 3 is used to store clean water, which is ordinary water.

[0077] (4) Primary cleaning tank

[0078] The primary cleaning tank 4 is used to add a surfactant solution into the heavy metal contaminated soil and stir the heavy metal contaminated soil and the surfactant solution to produce preliminarily cleaned soil and wastewater.

[0079] The primary cleaning tank 4 is connected to the surfactant dosing tank 2 by pipeline. Figure 4 As shown, the primary cleaning box 4 includes a primary drum 11 and a plurality of dosing nozzles 12 located inside the primary drum 11, and all the dosing nozzles 12 are connected to the surfactant dosing box 2 pipeline. The primary drum 11 contains heavy metal contaminated soil, and the dosing nozzles 12 are used to spray surfactant solution to add surfactant solution to the heavy metal contaminated soil. The primary drum 11 is used to rotate to stir the heavy metal contaminated soil and the surfactant solution, and use the surfactant solution to wash the heavy metal contaminated soil to produce soil and wastewater after preliminary cleaning. The spraying process of the dosing nozzle 12 and the rotation process of the primary drum 11 can be synchronized. During the rotation of the primary drum 11, with the help of the dosing nozzle 12 for spraying the surfactant solution, the heavy metal contaminated soil will be evenly infiltrated by the surfactant solution, helping the heavy metal contaminated soil to release the heavy metals adsorbed on the heavy metal contaminated soil, and producing soil and wastewater after preliminary cleaning.

[0080] (5) Secondary cleaning tank

[0081] The secondary cleaning tank 5 is connected to the primary cleaning tank 4 and is used to add clean water to the soil after preliminary cleaning and to stir the soil after preliminary cleaning and the clean water to produce cleaned soil and waste water.

[0082] In this embodiment, the primary cleaning tank 4 and the secondary cleaning tank 5 are connected and separated by a baffle. The baffle is controlled by the user or by the processor. After the baffle is lifted, the soil after preliminary cleaning in the primary cleaning tank 4 will naturally move to the secondary cleaning tank 5 due to centrifugal force and gravity.

[0083] The secondary cleaning tank 5 is connected to the water storage tank 3 by pipeline. Figure 5As shown, the secondary cleaning tank 5 includes a secondary drum 13 and a plurality of cleaning nozzles 14 located inside the secondary drum 13, and all the cleaning nozzles 14 are connected to the water storage tank 3 pipeline. The secondary drum 13 contains the preliminarily cleaned soil, and the cleaning nozzles 14 are used to spray clean water to add clean water to the preliminarily cleaned soil. The secondary drum 13 is used to rotate to stir the preliminarily cleaned soil and the clean water, and use the clean water to wash the preliminarily cleaned soil to produce cleaned soil and waste water. The spraying process of the cleaning nozzle 14 and the rotation process of the secondary drum 13 can be synchronized. During the rotation of the secondary drum 13, with the help of the cleaning nozzles 14 for spraying clean water, the heavy metals remaining on the preliminarily cleaned soil will be repeatedly washed until most of the heavy metals are taken away by the clean water, producing cleaned soil and waste water.

[0084] The primary drum 11 and the secondary drum 13 of this embodiment are both rotatable drums, and several nozzles capable of spraying clean water or surfactant solution are installed inside the primary drum 11 and the secondary drum 13. The biggest difference between the primary cleaning tank 4 and the secondary cleaning tank 5 is that the primary cleaning tank 4 is connected to the surfactant dosing tank 2 by pipeline, and the nozzle inside the primary drum 11 is a dosing nozzle 12 for spraying surfactant solution, while the secondary cleaning tank 5 is connected to the water storage tank 3 by pipeline, and the nozzle inside the secondary drum 13 is a cleaning nozzle 14 for spraying clean water. In this embodiment, the surfactant dosing tank 2 can be installed on the primary drum 11.

[0085] (6) First conductivity sensor

[0086] The first conductivity sensor 6 is installed at the drain outlet of the secondary cleaning tank 5 and is used to detect the first conductivity of the wastewater generated by the secondary cleaning tank 5 .

[0087] (7) Processor

[0088] The processor is connected to the first conductivity sensor for determining whether the first conductivity is greater than or equal to a first preset value. If so, the secondary cleaning tank 5 is controlled to work again until the first conductivity is less than the first preset value. At this time, the cleaned soil produced by the secondary cleaning tank 5 is clean soil after heavy metals are removed.

[0089] (8) Soil storage tank

[0090] The soil storage tank 7 is used to store clean soil and dry it through air circulation and sunlight.

[0091] Since the clean soil after washing has a very high water content, it needs to be stored in the soil storage tank 7 to achieve a certain degree of dehydration and finally transported to the mining site.

[0092] (9) Wastewater tank

[0093] The wastewater tank 8 is connected to the primary cleaning tank 4 and the secondary cleaning tank 5, and is used to store the wastewater generated by the primary cleaning tank 4 and the wastewater generated by the secondary cleaning tank 5, and mix the wastewater generated by the primary cleaning tank 4 and the wastewater generated by the secondary cleaning tank 5 to obtain mixed wastewater.

[0094] (10) Liquid level sensor

[0095] The liquid level sensor is installed in the wastewater tank 8 and is used to detect the liquid level of the mixed wastewater in the wastewater tank 8 .

[0096] (11) Second conductivity sensor 9

[0097] The second conductivity sensor 9 is installed at the bottom of the wastewater tank 8 and is used to detect the second conductivity of the mixed wastewater in the wastewater tank 8 .

[0098] The processor is respectively connected to the liquid level sensor and the second conductivity sensor 9 for communication, and is used to determine whether the liquid level has reached a preset level. If so, it is determined whether the second conductivity is less than a second preset value. If so, the mixed wastewater in the wastewater tank 8 is used as clean water, and the wastewater tank 8 is used to provide clean water to the secondary cleaning tank 5.

[0099] This embodiment provides a wastewater tank 8 with a conductivity detection function, which is used to store wastewater from two different drums. In the wastewater tank 8, the wastewater generated by the first drum 11 and the wastewater generated by the second drum 13 will be mixed to obtain mixed wastewater. In order to manage and optimize resource use, a second conductivity sensor 9 is installed in the wastewater tank 8 to detect the second conductivity of the mixed wastewater, which is a key indicator for judging whether the mixed wastewater is suitable for reuse. Conductivity is an indicator for measuring the total amount of dissolved solids in water. Through this indicator, the purity of water quality and possible metal pollutants contained in it can be inferred. If the second conductivity is less than the second preset value, it indicates that the content of metal pollutants in the mixed wastewater is low and it can still be safely reused without causing further pollution to the soil. Such reuse can significantly reduce the consumption of water resources and meet the goal of energy conservation and emission reduction. On the contrary, if the second conductivity is greater than or equal to the second preset value, it indicates that the content of metal pollutants in the mixed wastewater is high, and the continued use of this mixed wastewater may cause serious pollution to the soil. Therefore, this part of the mixed wastewater will not be used again, but transferred to the next treatment system for further purification or treatment to prevent further damage to the environment. Through such a setting, the efficiency and environmental safety of wastewater management can be ensured.

[0100] like Figure 6As shown, the working process of the soil cleaning and wastewater recovery component is as follows: the large pieces of original heavy metal contaminated soil are vibrated and separated into small particles of heavy metal contaminated soil by the soil screening machine 1, and the remaining large particles of stones and plant debris are discarded, and the small particles of heavy metal contaminated soil are transported to the primary drum 11 through the crawler. In the primary drum 11, the soil is chemically cleaned, and the dosing nozzle 12 in the primary drum 11 adds the surfactant solution into the primary drum 11. The primary drum 11 starts to rotate, stirring the heavy metal contaminated soil and the surfactant solution, so that the heavy metal contaminated soil and the surfactant solution are mixed, which helps to release the heavy metals attached to the heavy metal contaminated soil, and produce the initially cleaned soil and wastewater. The relatively high concentration of wastewater produced in this process is transported to the wastewater tank 8. At the same time, the primary drum 11 can be tilted. At this time, the outlet of the primary drum 11 is opened, and the initially cleaned soil in the primary drum 11 naturally moves toward the outlet and enters the secondary drum 13. In the secondary drum 13, the soil is cleaned with water, and the cleaning nozzle 14 in the secondary drum 13 adds clean water into the secondary drum 13. The secondary drum 13 starts to rotate, stirring the soil and clean water after preliminary cleaning, which is equivalent to using clean water to clean the soil after preliminary cleaning. The rotation of the secondary drum 13 can ensure that all the soil after preliminary cleaning is evenly contacted with the water flow, and help the clean water to flush the residual heavy metals, thereby generating cleaned soil and waste water. The waste water generated in this process is transported to the waste water tank 8. The cleaned soil is temporarily retained in the secondary drum 13. After the waste water in the secondary drum 13 is discharged, the conductivity is measured by the first conductivity sensor 6 located at the drain port of the secondary drum 13. If the measured first conductivity is greater than or equal to the first preset value, it means that there are still a large amount of heavy metals in the soil after cleaning, and it is necessary to rinse with water again, and re-measure the conductivity of the generated waste water after rinsing, until the first conductivity is less than the first preset value, it means that the heavy metals have been fully removed from the soil after cleaning, and clean soil is obtained, and then the clean soil is released.

[0101] All the wastewater generated is temporarily stored in the wastewater tank 8. When the mixed wastewater in the wastewater tank 8 reaches a certain capacity, the capacity can be characterized by the liquid level. Specifically, when the liquid level of the mixed wastewater in the wastewater tank 8 reaches the preset liquid level, the conductivity of the mixed wastewater is measured. If the second conductivity of the mixed wastewater is less than the second preset value, the mixed wastewater is regarded as reusable and can be used as clean water. At this time, the wastewater tank 8 can be used to provide clean water to the secondary drum 13; if the second conductivity of the mixed wastewater is greater than or equal to the second preset value, the mixed wastewater is regarded as non-reusable and needs to be discharged.

[0102] In this embodiment, soil cleaning and wastewater recovery components are provided. The sieved heavy metal contaminated soil will be cleaned chemically and with water to finally complete the soil cleaning. In this process, repeated cleaning is used to ensure the effectiveness of the cleaning. At the same time, the generated wastewater will be recycled as much as possible.

[0103] In order to process the non-reusable mixed wastewater in the wastewater tank 8, this embodiment further designs a heavy metal recovery component, such as Figure 7 and Figure 8 As shown, the details are as follows:

[0104] (1) Filter

[0105] The processor is also used to transport the mixed wastewater to the filter 15 through a vacuum pump when the second conductivity is greater than or equal to a second preset value. The filter 15 is used to filter the mixed wastewater in the wastewater tank 8 to obtain filtered wastewater.

[0106] The filter 15 includes a paper filter and a membrane filter connected in sequence. The paper filter is used to filter the mixed wastewater to perform solid-liquid separation to obtain preliminarily filtered wastewater; the membrane filter is used to filter the preliminarily filtered wastewater to perform solid-liquid separation to obtain filtered wastewater.

[0107] The filter 15 of this embodiment is composed of two parts: a paper filter and a membrane filter. These two parts work together to convert the mixed wastewater into filtered wastewater. This process will remove larger particles that may affect the electrochemical precipitation process and the reverse osmosis process. The filtered wastewater obtained through this process is then transported by the vacuum pump 16 to the multifunctional electrochemical reaction cell 17.

[0108] (2) Heavy metal recovery device

[0109] The heavy metal recovery device is connected to the filter 15 and the reverse osmosis device 22, and is used to determine whether the third conductivity of the influent of the heavy metal recovery device is greater than or equal to the third preset value. If so, the influent of the heavy metal recovery device is electrochemically precipitated by the electrode 18 to recover the heavy metals from the influent of the heavy metal recovery device to obtain the recovered heavy metals and the wastewater to be discharged; if not, the influent of the heavy metal recovery device is transported to the reverse osmosis device 22. The influent of the heavy metal recovery device is the filtered wastewater or the mixed water of the filtered wastewater and concentrated water.

[0110] Heavy metal recovery equipment includes:

[0111] The electrochemical reaction cell 17 is equipped with a water inlet of a heavy metal recovery device.

[0112] The electrode 18 is installed inside the electrochemical reaction cell 17 and is used to electrochemically precipitate the influent of the heavy metal recovery device, recover the heavy metals from the influent of the heavy metal recovery device, and obtain the recovered heavy metals and wastewater to be discharged.

[0113] The third conductivity sensor 19 is installed inside the electrochemical reaction cell 17 and is used to detect the third conductivity of the influent water of the heavy metal recovery device.

[0114] The processor is in communication with the third conductivity sensor 19 and the power supply 20, and is used to determine whether the third conductivity of the influent water of the heavy metal recovery device is greater than or equal to a third preset value. If so, the power supply 20 is controlled to operate.

[0115] The power source 20 is electrically connected to the electrode 18 and is used to supply power to the electrode 18 .

[0116] The electrochemical reaction cell 17 of this embodiment not only receives the filtered wastewater output by the filter 15, but also receives the concentrated water output by the reverse osmosis device 22. In this embodiment, the filtered wastewater and concentrated water entering the electrochemical reaction cell 17 are collectively referred to as the influent of the heavy metal recovery device. The design feature of the electrochemical reaction cell 17 is its inclined bottom, which facilitates the collection and use of the influent. Through this design, the influent can be collected again and recycled. The electrochemical reaction cell 17 can not only process influent of different concentrations, but also transport the influent to the reverse osmosis device 22, which depends on the concentration of the influent.

[0117] A third conductivity sensor 19 is installed in the electrochemical reaction cell 17, a power supply 20 is installed outside the electrochemical reaction cell 17, and an electrode 18 with adjustable height is installed in the electrochemical reaction cell 17 to adapt to different water flows and water surface inclinations. The power supply 20 is electrically connected to the electrode 18, and the electrode 18 is used to recover heavy metals from the incoming water through electrochemical precipitation technology when powered by the power supply 20. Only when the heavy metals in the influent water reach a certain concentration, that is, when the third conductivity is greater than or equal to the third preset value, the power supply 20 will start to work and supply power to the electrode 18. At this time, the electrode 18 recovers the heavy metals from the influent water by electrochemical precipitation technology. Specifically, the electrode 18 adsorbs the heavy metals in the influent water of various concentrations by electrochemical precipitation. After the electrochemical precipitation is completed, the electrode 18 can be taken out, and then the heavy metals attached to the electrode 18 can be collected by physical means. Since the volume of the influent water has been greatly reduced at this time, and the concentration will be greatly increased at the same time, it may cause the reverse osmosis device 22 to be unusable after entering the reverse osmosis device 22. Therefore, the wastewater to be discharged after the electrochemical precipitation will be discharged through the reverse osmosis device 22. When the third conductivity is less than the third preset value, the influent water in the electrochemical reaction cell 17 will be transported to the reverse osmosis device 22 under the pressure of the high-pressure pump 21.

[0118] (3) Reverse osmosis device

[0119] The reverse osmosis device 22 is connected to the heavy metal recovery device, and is used to perform reverse osmosis treatment on the influent water of the heavy metal recovery device to generate concentrated water and produced water, and transport the concentrated water to the heavy metal recovery device.

[0120] In this embodiment, the reverse osmosis device 22 is also connected to the water storage tank 3 for conveying the produced water to the water storage tank 3 .

[0121] After the influent of this embodiment enters the reverse osmosis device 22, the pressure will be controlled to control the water flux. In this process, the heavy metal concentration in the influent will be increased, the total influent amount will be reduced, and concentrated water and a certain amount of produced water will be generated. The produced water will enter the water storage tank 3 and will be used for soil cleaning later. The concentrated water will be transported to the electrochemical reaction cell 17, and the reverse osmosis process will be repeated to continuously increase the total metal content in the influent until the third conductivity in the influent is greater than or equal to the third preset value. The power supply 20 will start to work and supply power to the electrode 18, and the electrode 18 will start electrochemical precipitation in the electrochemical reaction cell 17. The mixed wastewater is concentrated by the heavy metal recovery component to improve the efficiency of its electrochemical precipitation. Finally, the heavy metals collected by electrochemical precipitation can generate economic benefits, and the produced water can be reused to improve resource utilization.

[0122] In the cleaning and heavy metal recovery device for removing heavy metals from soil provided in this embodiment, the sieved heavy metal contaminated soil will be cleaned by chemical cleaning and water cleaning to obtain clean soil. In this process, the mixed wastewater generated will be recycled as much as possible, and at the same time, the effectiveness of cleaning will be ensured by repeated cleaning. In addition, if the second conductivity of the mixed wastewater is greater than or equal to the second preset value, the generated mixed wastewater will be used in the next treatment step. Specifically, after being filtered by the filter 15, the filtered wastewater will enter the electrochemical reaction cell 17, and from there enter the reverse osmosis device 22 for concentration. This process will simultaneously produce produced water and concentrated water. The produced water will be reused in the soil cleaning process, and the concentrated water will enter the electrochemical reaction cell 17 again, repeating until the third conductivity is greater than or equal to the third preset value, and then electrochemical precipitation is started to collect the heavy metals therein, and the wastewater to be discharged that cannot be treated by the reverse osmosis device 22 will be discharged. This embodiment recovers heavy metals while removing heavy metals from the soil, and in this process ensures the circulation of water and the effectiveness of soil cleaning and metal recovery.

[0123] Example 2

[0124] This embodiment provides a method for cleaning heavy metal contaminated soil and recovering heavy metals, which is applied to the device for cleaning heavy metal contaminated soil and recovering heavy metals described in Example 1. The method for cleaning heavy metal contaminated soil and recovering heavy metals comprises:

[0125] (1) Controlling the operation of the primary cleaning tank to add a surfactant solution into the heavy metal contaminated soil, and stirring the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater.

[0126] (2) Controlling the operation of the secondary cleaning tank to add clean water to the initially cleaned soil, and stirring the initially cleaned soil and the clean water to generate cleaned soil and wastewater.

[0127] (3) Obtaining the first conductivity of the wastewater generated by the secondary cleaning tank.

[0128] (4) Determine whether the first conductivity is greater than or equal to a first preset value.

[0129] (5) If yes, the cleaned soil is used as the preliminary cleaned soil and the process returns to the step of “controlling the operation of the secondary cleaning tank”.

[0130] (6) If not, the cleaned soil produced by the secondary cleaning tank is used as the clean soil after heavy metal removal.

[0131] (7) Treat the wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank to recover the heavy metals in the wastewater.

[0132] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A device for cleaning heavy metal contaminated soil and recovering heavy metals, characterized in that: The heavy metal contaminated soil cleaning and heavy metal recovery device comprises: A primary cleaning tank is used to add a surfactant solution to the heavy metal contaminated soil and stir the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater; A secondary cleaning tank connected to the primary cleaning tank, used to add clean water to the initially cleaned soil, and to stir the initially cleaned soil and the clean water to produce cleaned soil and wastewater; A first conductivity sensor, installed at the drain outlet of the secondary cleaning tank, for detecting a first conductivity of wastewater generated by the secondary cleaning tank; a processor, which is in communication connection with the first conductivity sensor, and is used to determine whether the first conductivity is greater than or equal to a first preset value, and if so, control the secondary cleaning box to work again until the first conductivity is less than the first preset value, at which time the cleaned soil produced by the secondary cleaning box is clean soil after heavy metals are removed; The heavy metal recovery component is used to treat the wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank to recover the heavy metals in the wastewater.

2. The heavy metal contaminated soil cleaning and heavy metal recovery device according to claim 1, characterized in that: The heavy metal contaminated soil cleaning and heavy metal recovery device also includes: The soil screening machine is used to screen the original heavy metal contaminated soil obtained by mining to obtain heavy metal contaminated soil.

3. The heavy metal contaminated soil cleaning and heavy metal recovery device according to claim 1, characterized in that: The heavy metal contaminated soil cleaning and heavy metal recovery device also includes: A surfactant dosing box, used for storing surfactant solution; Water storage tanks for storing clean water; The primary cleaning tank is connected to the surfactant dosing tank pipeline; the primary cleaning tank includes a primary drum and a plurality of dosing nozzles located inside the primary drum, and all the dosing nozzles are connected to the surfactant dosing tank pipeline; the primary drum is filled with heavy metal contaminated soil, the dosing nozzles are used to spray the surfactant solution to add the surfactant solution to the heavy metal contaminated soil, and the primary drum is used to rotate to stir the heavy metal contaminated soil and the surfactant solution to produce soil and wastewater after preliminary cleaning; The secondary cleaning tank is connected to the water tank pipeline; the secondary cleaning tank includes a secondary drum and a plurality of cleaning nozzles located inside the secondary drum, and all the cleaning nozzles are connected to the water tank pipeline; the secondary drum is filled with preliminarily cleaned soil, the cleaning nozzles are used to spray clean water to add clean water to the preliminarily cleaned soil, the secondary drum is used to rotate to stir the preliminarily cleaned soil and the clean water, and the preliminarily cleaned soil is washed with the clean water to generate cleaned soil and wastewater.

4. The heavy metal contaminated soil cleaning and heavy metal recovery device according to claim 3, characterized in that: The heavy metal contaminated soil cleaning and heavy metal recovery device also includes: A wastewater tank connected to the primary cleaning tank and the secondary cleaning tank, used to store wastewater generated by the primary cleaning tank and wastewater generated by the secondary cleaning tank to obtain mixed wastewater; A liquid level sensor, installed in the wastewater tank, for detecting the liquid level of the mixed wastewater in the wastewater tank; A second conductivity sensor is installed at the bottom of the wastewater tank and is used to detect a second conductivity of the mixed wastewater in the wastewater tank; The processor is respectively connected to the liquid level sensor and the second conductivity sensor for communication, and is used to determine whether the liquid level has reached a preset level. If so, it is determined whether the second conductivity is less than a second preset value. If so, the mixed wastewater in the wastewater tank is used as clean water, and the wastewater tank is used to provide clean water to the secondary cleaning tank.

5. The device for cleaning heavy metal contaminated soil and recovering heavy metals according to claim 4, characterized in that: Heavy metal recycling parts include: A filter, used for filtering the mixed wastewater in the wastewater tank to obtain filtered wastewater; A heavy metal recovery device is connected to the filter and the reverse osmosis device, and is used to determine whether the third conductivity of the influent of the heavy metal recovery device is greater than or equal to a third preset value. If so, the influent of the heavy metal recovery device is electrochemically precipitated using electrodes to recover heavy metals from the influent of the heavy metal recovery device to obtain recovered heavy metals and wastewater to be discharged; if not, the influent of the heavy metal recovery device is transported to the reverse osmosis device; wherein the influent of the heavy metal recovery device is filtered wastewater or a mixture of filtered wastewater and concentrated water; The reverse osmosis device is connected to the heavy metal recovery device and is used to perform reverse osmosis treatment on the influent water of the heavy metal recovery device to generate concentrated water and produced water, and transport the concentrated water to the heavy metal recovery device.

6. The heavy metal contaminated soil cleaning and heavy metal recovery device according to claim 5, characterized in that: The filter includes a paper filter and a membrane filter connected in sequence; The paper filter is used to filter the mixed wastewater to separate the solid and liquid and obtain the initially filtered wastewater; The membrane filter is used to filter the wastewater after preliminary filtration to perform solid-liquid separation to obtain filtered wastewater.

7. The device for cleaning heavy metal contaminated soil and recovering heavy metals according to claim 5, characterized in that: Heavy metal recovery equipment includes: Electrochemical reaction cell, water inlet equipped with heavy metal recovery device; The electrode is installed inside the electrochemical reaction cell and is used to electrochemically precipitate the influent of the heavy metal recovery device, recover the heavy metals from the influent of the heavy metal recovery device, and obtain the recovered heavy metals and wastewater to be discharged; A third conductivity sensor, installed inside the electrochemical reaction cell, for detecting a third conductivity of the influent water of the heavy metal recovery device; a processor, which is in communication with the third conductivity sensor and the power supply, and is used to determine whether the third conductivity of the influent water of the heavy metal recovery device is greater than or equal to a third preset value, and if so, control the power supply to operate; A power source is electrically connected to the electrode and is used to supply power to the electrode.

8. The device for cleaning heavy metal contaminated soil and recovering heavy metals according to claim 5, characterized in that: The reverse osmosis device is also connected to a water storage tank for conveying produced water to the water storage tank.

9. The device for cleaning heavy metal contaminated soil and recovering heavy metals according to claim 5, characterized in that: The processor is also used to transport the mixed wastewater to the filter when the second conductivity is greater than or equal to a second preset value.

10. A method for cleaning heavy metal contaminated soil and recovering heavy metals, applied to the device for cleaning heavy metal contaminated soil and recovering heavy metals according to any one of claims 1 to 9, characterized in that: The method for cleaning heavy metal contaminated soil and recovering heavy metals comprises: Controlling the operation of the primary cleaning tank to add a surfactant solution to the heavy metal contaminated soil, and stirring the heavy metal contaminated soil and the surfactant solution to produce initially cleaned soil and wastewater; Controlling the operation of the secondary cleaning tank to add clean water to the initially cleaned soil, and to stir the initially cleaned soil and the clean water to produce cleaned soil and waste water; obtaining a first conductivity of wastewater generated by the secondary cleaning tank; Determining whether the first conductivity is greater than or equal to a first preset value; If yes, the cleaned soil is used as the primary cleaned soil and the process returns to the step of "controlling the operation of the secondary cleaning box"; If not, the cleaned soil produced by the secondary cleaning tank is used as the clean soil after heavy metal removal; The wastewater generated by the primary cleaning tank and the wastewater generated by the secondary cleaning tank are treated to recover the heavy metals in the wastewater.

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