CN219112500U

CN219112500U - System for treating heavy metal contaminated soil by using foaming agent-containing shield slag soil

Info

Publication number: CN219112500U
Application number: CN202223531732.2U
Authority: CN
Inventors: 刘烨煊; 李青; 邹永立; 刘武; 王旭伟; 胡娜
Original assignee: China Railway Hi Tech Industry Corp Ltd; China Railway Environmental and Technology Engineering Co Ltd
Current assignee: China Railway Hi Tech Industry Corp Ltd; China Railway Environmental and Technology Engineering Co Ltd
Priority date: 2022-12-29
Filing date: 2022-12-29
Publication date: 2023-06-02
Anticipated expiration: 2032-12-29

Abstract

The utility model provides a system for treating heavy metal contaminated soil by using shield residue soil containing a foaming agent. The system comprises a soil mixing mechanism, a pulping mechanism, a particle separating mechanism, an elution mechanism, a first wastewater treatment mechanism and a second wastewater treatment mechanism, wherein a feed inlet and a pulp outlet of the pulping mechanism are respectively communicated with a soil discharge outlet of the soil mixing mechanism and the particle separating mechanism, a water inlet of the pulping mechanism is communicated with a first water outlet of the first wastewater treatment mechanism and/or a water outlet of the second wastewater treatment mechanism, an outlet of the particle separating mechanism is communicated with the feed inlet of the elution mechanism, a liquid outlet of the elution mechanism is communicated with a water inlet of the first wastewater treatment mechanism, and a second water outlet of the first wastewater treatment mechanism is communicated with a water inlet of the second wastewater treatment mechanism. The system of the utility model utilizes the shield residue soil containing the foaming agent which needs harmless treatment to treat the heavy metal polluted soil, thereby achieving the purpose of treating the pollution by using the pollution and reducing the cost of treating the polluted soil.

Description

System for treating heavy metal contaminated soil by using foaming agent-containing shield slag soil

Technical Field

The utility model belongs to the technical field of heavy metal contaminated soil treatment, and particularly relates to a system for treating heavy metal contaminated soil by using shield slag soil containing a foaming agent.

Background

The foaming agent is added into the dregs, so that the mechanical abrasion of the shield machine can be effectively reduced, the plastic fluidity of soil in a soil bin can be adjusted, and the water permeability of the dregs can be reduced. The construction of urban subways generates a large amount of shield slag soil containing the foaming agent, and the foaming agent has potential harm to the growth of organisms and needs to be subjected to harmless treatment. The prior art mainly adopts the method for treating the shield slag soil containing the foaming agent to carry out landfill treatment after dehydration, and the value of the shield slag soil is not utilized enough.

The prior art mainly adopts methods of solidification and stabilization, leaching and the like for treating the heavy metal polluted soil, and has the defect of higher treatment cost due to the addition of solidification and stabilization agents, leaching agents and the like in the treatment process.

Disclosure of Invention

The utility model aims to provide a system for treating heavy metal contaminated soil by utilizing shield slag soil containing a foaming agent, which needs innocent treatment, so that the purpose of treating the contaminated soil by using the sewage is achieved, and the cost of treating the contaminated soil can be reduced.

In order to achieve the above purpose, the utility model provides a system for treating heavy metal contaminated soil by using foaming agent-containing shield muck, which comprises a soil mixing mechanism, a pulping mechanism, a particle separating mechanism, an eluting mechanism, a first wastewater treatment mechanism for removing heavy metals and a second wastewater treatment mechanism for removing foam agents, wherein a soil feed inlet of the pulping mechanism is communicated with a soil discharge outlet of the soil mixing mechanism, a water inlet of the pulping mechanism is communicated with a first water outlet of the first wastewater treatment mechanism and/or a water outlet of the second wastewater treatment mechanism, and a slurry outlet of the pulping mechanism is communicated with a feed inlet of the particle separating mechanism; the outlet of the particle separating mechanism is communicated with the feeding port of the eluting mechanism, the liquid outlet of the eluting mechanism is communicated with the water inlet of the first wastewater treatment mechanism, and the second water outlet of the first wastewater treatment mechanism is communicated with the water inlet of the second wastewater treatment mechanism.

In a specific embodiment, the soil mixing mechanism comprises a shell, a soil feeding hole arranged at the front end of the shell, a soil discharging hole arranged at the rear end of the shell and a spiral stirrer arranged in the shell.

In a specific embodiment, the particle separating mechanism comprises a first separating unit for separating large-size sundries and large-particle-size aggregates, a second separating unit for separating medium-particle-size aggregates and a third separating unit for separating fine aggregates, wherein a feed inlet of the first separating unit is communicated with a slurry outlet of the slurry making mechanism, a discharge outlet of the first separating unit is communicated with a feed inlet of the second separating unit, a discharge outlet of the second separating unit is communicated with a feed inlet of the third separating unit, and a discharge outlet of the third separating unit is communicated with a feed inlet of the elution mechanism.

In a specific embodiment, the first separation unit comprises a vibrating screen and a first flushing machine for cleaning oversize products of the vibrating screen, a feed inlet of the vibrating screen is communicated with a pulp outlet of the pulping machine, an undersize product outlet of the vibrating screen is communicated with the second separation unit, the first oversize products and first suspension are obtained after separation by the vibrating screen, the first oversize products are large-size sundries and large-particle-size aggregates, and the first suspension enters the second separation unit through an undersize product outlet of the vibrating screen.

In a specific embodiment, the second separation unit comprises a drum screen and a second flushing machine for cleaning oversize products of the drum screen, a feed inlet of the drum screen is communicated with an undersize product outlet of the vibrating screen, an undersize product outlet of the drum screen is communicated with the third separation unit, the oversize products and second suspension are obtained after separation by the drum screen, the second oversize products are medium-grain-diameter aggregates, and the second suspension enters the third separation unit through the undersize product outlet of the drum screen.

In a specific embodiment, the third separation unit comprises a cyclone and a wheel sand washer which are communicated, the feed inlet of the cyclone is communicated with the undersize outlet of the drum screen, the underflow opening of the cyclone is communicated with the feed inlet of the wheel sand washer, and the overflow opening of the cyclone and the discharge opening of the wheel sand washer are both communicated with the feed inlet of the elution mechanism.

In a specific embodiment, the elution mechanism comprises a flocculation tank and a plate-and-frame filter press, wherein a feed inlet of the flocculation tank is communicated with an outlet of the particle separation mechanism, a concentrate outlet of the flocculation tank is communicated with a feed inlet of the plate-and-frame filter press, and a supernatant outlet of the flocculation tank and a filtrate outlet of the plate-and-frame filter press are both communicated with a water inlet of the first wastewater treatment mechanism.

In a specific embodiment, the elution mechanism further comprises a doser in communication with the inlet of the flocculation tank, the doser for adding a flocculant to the flocculation tank.

In a specific embodiment, the system further comprises a conveying mechanism, wherein the conveying mechanism comprises a conveying belt communicated with the soil mixing mechanism and the pulping mechanism, a lifting hopper communicated with the pulping mechanism and the particle separating mechanism, a slurry pump communicated with the particle separating mechanism and the eluting mechanism, a first water pump communicated with the eluting mechanism and the first wastewater treatment mechanism, and a second water pump communicated with the first wastewater treatment mechanism and the second wastewater treatment mechanism.

In a specific embodiment, the conveying mechanism further comprises a first spiral feeder communicated with the vibrating screen and the rotary screen, and a second spiral feeder communicated with the rotary screen and the cyclone.

The beneficial effects of the utility model at least comprise:

the utility model provides a system for treating heavy metal contaminated soil by using foaming agent-containing shield muck, which comprises a soil mixing mechanism, a pulping mechanism, a particle separation mechanism, an elution mechanism, a first wastewater treatment mechanism for removing heavy metals and a second wastewater treatment mechanism for removing foam agents, wherein a soil feed inlet of the pulping mechanism is communicated with a soil discharge outlet of the soil mixing mechanism, a water inlet of the pulping mechanism is communicated with a first water outlet of the first wastewater treatment mechanism and/or a water outlet of the second wastewater treatment mechanism, and a slurry outlet of the pulping mechanism is communicated with a feed inlet of the particle separation mechanism; the outlet of the particle separating mechanism is communicated with the feeding port of the eluting mechanism, the liquid outlet of the eluting mechanism is communicated with the water inlet of the first wastewater treatment mechanism, and the second water outlet of the first wastewater treatment mechanism is communicated with the water inlet of the second wastewater treatment mechanism. Thus, the foam agent-containing shield muck and heavy metal polluted soil which are uniformly mixed by the soil mixing mechanism enter the pulping mechanism to perform pulping to obtain a mixture comprising aggregate and slurry, the foam agent is subjected to primary elution reaction on heavy metal, the mixture is separated and graded by the particle separating mechanism to obtain multistage aggregate and slurry, the slurry enters the eluting mechanism to perform secondary elution reaction on the heavy metal by the foam agent, mud cakes and wastewater are obtained after the separation by the eluting mechanism, and the wastewater enters the first wastewater treatment mechanism to remove heavy metal and/or the second wastewater treatment mechanism to remove foam agent and then is reused or directly discharged, so that the purpose of pollution control by pollution is achieved, the comprehensive utilization of resources is realized, and the cost of soil treatment is reduced.

In addition to the objects, features and advantages described above, the present utility model has other objects, features and advantages. The present utility model will be described in further detail with reference to the drawings.

Drawings

FIG. 1 is a schematic structural diagram of a system for treating heavy metal contaminated soil with foaming agent-containing shield slag soil according to an embodiment of the present utility model;

fig. 2 is a process flow diagram of a system for treating heavy metal contaminated soil with foaming agent-containing shield slag soil according to an embodiment of the utility model.

Reference numerals illustrate:

Detailed Description

The embodiments of the utility model are described in detail below with reference to the attached drawings, but the utility model can be defined and covered in a number of different embodiments according to the claims.

Referring to fig. 1 and 2, the present utility model provides a system 100 for treating heavy metal contaminated soil with foaming agent shield slag, wherein the system 100 comprises a soil mixing mechanism 10, a pulping mechanism 20, a particle separating mechanism 30, an eluting mechanism 40, a first wastewater treatment mechanism 50 and a second wastewater treatment mechanism 60 which are sequentially communicated.

The soil mixing mechanism 10 is used for mixing the shield slag soil containing the foaming agent and the heavy metal polluted soil to obtain mixed soil; the pulping mechanism 20 is used for mixing the mixed soil with water to obtain a mixture comprising aggregate and slurry; the particle separating mechanism 30 is used for separating aggregates of different grades and obtaining clean large-medium-particle-diameter aggregates and slurry comprising fine aggregates, heavy metals and foaming agents; the elution mechanism 40 is used for further separating heavy metals and foaming agents in the fine aggregate and the slurry into water phases to obtain mud cakes and wastewater containing the heavy metals and the foaming agents, the wastewater enters the first wastewater treatment mechanism 50 for further treatment, the mud cakes which are detected to be qualified are subjected to landfill treatment or recycling, and the mud cakes which are not detected to be qualified are returned to the pulping mechanism 20 together with the wastewater from which the heavy metals are removed by the first wastewater treatment mechanism 50 for further pulping; the first wastewater treatment mechanism 50 is used for removing heavy metals in wastewater, the second wastewater treatment mechanism 60 is used for removing foaming agent in wastewater, and the treated wastewater reaching standards can be used for pulping by the pulping mechanism 20 or can be directly discharged or used for other purposes.

According to the utility model, by utilizing the property that the foaming agent can be combined with heavy metal ions in soil, when the pulping mechanism 20 mixes the mixed soil with water, the foaming agent can adsorb the heavy metal ions in the soil and activate the heavy metal in the soil to be separated from the aggregate and enter the slurry, so that the foaming agent and the heavy metal are combined, and both substances enter liquid phases to finish primary elution; the utility model adopts a secondary elution technology, can adsorb heavy metal ions in soil by using the foaming agent in shield slag soil, achieves the purpose of treating sewage by using sewage, is convenient for subsequent treatment of the wastewater containing heavy metals, and has the advantages of low treatment cost and good treatment effect.

The soil mixing mechanism 10 comprises a shell 11, a soil feeding hole 12 arranged at the front end of the shell 11, a soil discharging hole 13 arranged at the rear end of the shell 11 and a spiral stirrer 14 arranged in the shell 11.

The shell 11 is provided with an accommodating space for accommodating shield slag soil and heavy metal contaminated soil, the soil feeding port 12 is used for feeding the shield slag soil and the heavy metal contaminated soil, the soil discharging port 13 is communicated with the soil feeding port of the pulping mechanism 20, and the spiral stirrer 14 is used for stirring the shield slag soil and the heavy metal contaminated soil to be uniformly mixed.

In this embodiment, the number of the soil inlets 12 is one, that is, the shield slag soil and the heavy metal contaminated soil are fed from the same inlet, and in other implementations, the number of the soil inlets 12 may be two, and the shield slag soil and the heavy metal contaminated soil are fed from different soil inlets 12.

The pulping mechanism 20 comprises a pulping pool and a stirring device arranged in the pulping pool, a water inlet of the pulping mechanism 20, a soil feed inlet of the pulping mechanism 20 and a pulp outlet of the pulping mechanism 20 are all arranged on the pulping pool, mixed soil and water are uniformly stirred in the pulping pool by the stirring device to obtain a mixture comprising aggregate and slurry, and primary elution of the foaming agent on heavy metals in the soil is completed.

Preferably, the pulping mechanism 20 further includes an outlet in communication with the elution mechanism 40.

The particle separating mechanism 30 comprises a first separating unit 31 for separating large-sized sundries and large-sized aggregates, a second separating unit 32 for separating medium-sized aggregates and a third separating unit 33 for separating fine aggregates, wherein a feed port of the first separating unit 31 is communicated with a slurry outlet of the slurry making mechanism 20, a discharge port of the first separating unit 31 is communicated with a feed port of the second separating unit 32, a discharge port of the second separating unit 32 is communicated with a feed port of the third separating unit 33, and a discharge port of the third separating unit 33 is communicated with a feed port of the eluting mechanism 40.

It will be appreciated that the particle size of the aggregates used for separation by the first, second and

third separation units

31, 32 and 33 is from large to small, and the particle size of the aggregates to be separated by the first, second and

third separation units

31, 32 and 33 is determined by the particle sizes of the raw shield slag and heavy metal soil. For ease of understanding, if the particle size range of the aggregate is 0 to 10 cm, then the aggregate of more than 5 cm may be referred to as large particle size aggregate, the aggregate of 0.8 cm to 5 cm may be referred to as medium particle size aggregate, and the aggregate of less than 0.8 cm may be referred to as fine aggregate; if the particle size range of the aggregate is 0 to 5 cm, the aggregate of more than 3 cm may be referred to as a large-size aggregate, the aggregate of 0.8 cm to 3 cm may be referred to as a medium-size aggregate, and the aggregate of less than 0.8 cm may be referred to as a fine aggregate.

In this embodiment, the first separation unit 31 includes a vibrating screen 311, and a first flushing machine for cleaning oversize products of the vibrating screen 311, a feed inlet of the vibrating screen 311 is communicated with a pulp outlet of the pulp machine 20, an undersize product outlet of the vibrating screen 311 is communicated with the second separation unit 32, and the undersize products and a first suspension are obtained after separation by the vibrating screen 311, wherein the first oversize products are large-size impurities and large-particle-size aggregates, and the first suspension enters the second separation unit through the undersize product outlet of the vibrating screen 311.

It should be noted that, the vibrating screen 311 and the first flushing machine may be integrally provided, that is, the vibrating screen 311 is provided with the first flushing machine, or may be two independent devices, that is, the vibrating screen 311 is provided with the first flushing machine, and both the two setting modes do not affect the implementation of the technical scheme of the present utility model. By providing a first flushing machine to clean the foam and heavy metals on the oversize product of the vibrating screen 311 and to enter the first suspension, the cleaned first oversize product can be recycled.

Preferably, the vibration 311 is a two-layer vibrating screen with a water spraying device (first flushing machine) for flushing while vibrating. The large-size sundries refer to branches, plastics and the like.

In this embodiment, the second separation unit 32 includes a drum screen 321, and a second flushing machine for cleaning the oversize product of the drum screen 321, where a feed inlet of the drum screen 321 is communicated with an undersize outlet of the vibrating screen 311, and an undersize outlet of the drum screen is communicated with the third separation unit 33, and after separation by the drum screen 321, a second oversize product and a second suspension are obtained, and the second suspension enters the third separation unit 33 through an undersize outlet of the drum screen.

It should be noted that, the trommel 321 and the second flushing machine may be integrally provided, that is, the trommel 321 may be provided with the second flushing machine, or may be two independent devices, that is, the trommel 311 is provided with the second flushing machine, and both the two setting modes do not affect the implementation of the technical scheme of the present utility model. By providing a second flushing machine to clean the foam and heavy metals on the oversize product of the trommel 321 and to enter the second suspension, the cleaned second oversize product can be recycled.

Preferably, the trommel 321 is provided with a water jet (second flushing device), i.e. a commercially available trommel 321 has the function of flushing oversize.

The aperture of the trommel 321 is smaller than the aperture of the vibrating screen 311.

In this embodiment, the third separation unit 33 includes a cyclone 331 and a wheel sand washer 332 that are connected, a feed inlet of the cyclone 331 is connected to an undersize outlet of the drum screen 321, a bottom flow port of the cyclone 331 is connected to a feed inlet of the wheel sand washer 332, and an overflow port of the cyclone 331 and a discharge port of the wheel sand washer 332 are both connected to the elution mechanism 40.

After being separated by the cyclone 331, the fine aggregate with a relatively large particle size is discharged from the bottom flow port of the cyclone 331, enters the wheel type sand washer 332 to further clean the foaming agent and heavy metal remained on the surface of the fine aggregate, and then enters the eluting mechanism 40, and the fine aggregate with a relatively small particle size discharged from the overflow port of the cyclone 331 directly enters the eluting mechanism 40.

Preferably, the elution mechanism 40 includes a flocculation tank 41, a plate-and-frame filter press 42, and a doser in communication with the drug inlet of the flocculation tank 41. The feed inlet of the flocculation tank 41 is communicated with the outlet of the particle separating mechanism 30, the concentrate outlet of the flocculation tank 41 is communicated with the feed inlet of the plate-and-frame filter press 42, and the supernatant outlet of the flocculation tank 41 and the filtrate outlet of the plate-and-frame filter press 42 are both communicated with the water inlet of the first wastewater treatment mechanism 50.

The flocculant is added into the flocculation tank 41 through the chemical adder to flocculate, precipitate and concentrate mud, the supernatant directly enters the first wastewater treatment mechanism 50 through the supernatant outlet of the flocculation tank 41, the concentrated solution enters the plate-and-frame filter press 42 through the concentrated solution outlet of the flocculation tank 41 to further filter to obtain mud cakes and filtrate, the filtrate enters the first wastewater treatment mechanism 50, the mud cakes are further treated based on the detection result after the residual quantity of the co-foaming agent and the heavy metal is detected by the detection personnel, the qualified mud cakes can be directly buried or subjected to other recycling treatment, and the unqualified mud cakes are returned to the pulping mechanism 20 to be eluted again. In this embodiment, unqualified mud cakes are detected and accumulated in a partition. After the primary treatment of the shield slag soil and the heavy metal contaminated soil containing the foaming agent is completed, the shield slag soil and the heavy metal contaminated soil are shoveled into a pulping pool by a forklift in a concentrated manner, and secondary pulping is carried out.

The flocculant added to flocculation tank 41 is a commercially available flocculant, and belongs to the prior art.

The first wastewater treatment mechanism 50 is used for removing heavy metals, and the first wastewater treatment mechanism 50 is a device disclosed in the prior art and is obtained directly through commercial purchasing.

The water inlet of the first wastewater treatment mechanism 50 is respectively communicated with the supernatant outlet of the flocculation tank 41 and the filtrate outlet of the plate-and-frame filter press 42, the first water outlet of the first wastewater treatment mechanism 50 is communicated with the water inlet of the pulping mechanism 20, and the second water outlet of the first wastewater treatment mechanism 50 is communicated with the water inlet of the second wastewater treatment mechanism 60.

The wastewater after being treated by the first wastewater treatment mechanism 50 is determined to be going based on the mud cake detection result, and if the heavy metals remained in the mud cake are qualified, the wastewater after removing the heavy metals can directly enter the second wastewater treatment mechanism 60 for treatment of the foam removing agent; if the residual heavy metal in the mud cake exceeds the standard, the waste water for removing the heavy metal and the unqualified mud cake both need to enter a pulping tank for pulping, enter an elution mechanism 40 after pulping, further utilize a first-stage elution reaction and a second-stage elution reaction for treatment until the qualified mud cake is obtained, and the step can utilize a foaming agent in the waste water for eluting the heavy metal again.

In this embodiment, the system further includes a conveying mechanism, where the conveying mechanism includes a conveying belt that communicates the soil mixing mechanism 10 and the pulping mechanism 20, a hopper that communicates the pulping mechanism 20 and the vibrating screen 311 in the particle separating mechanism 30, a first spiral feeder 71 that communicates the vibrating screen 311 and the drum screen 321, a second spiral feeder 72 that communicates the drum screen 321 and the cyclone 331, and a slurry pump that communicates the wheel sand washer 332 and the elution mechanism 40.

The conveying mechanism further comprises a plurality of water pumps, the supernatant of the flocculation tank 41 and the filtrate of the plate-and-frame filter press 42 are pumped to the first wastewater treatment device 40 through the first water pump, the wastewater from which heavy metals are removed through the first wastewater treatment device 40 is pumped to the second wastewater treatment device 50 through the second water pump or pumped to the pulping mechanism 20 through the third water pump, and the wastewater from which foaming agents are removed through the second wastewater treatment device 50 is pumped to the pulping mechanism 20 through the fourth water pump.

The treatment process of the heavy metal contaminated soil is further described, specifically:

the heavy metal contaminated soil and the shield residue soil containing the foaming agent enter the soil mixing and stirring mechanism 10 from a soil feed inlet of the soil mixing and stirring mechanism, the mixing time and the stirring frequency are controlled by a spiral stirrer, the mixed soil is uniformly stirred, and the foaming agent and the heavy metal are primarily uniformly mixed. The evenly mixed soil is conveyed into a pulping pool of the pulping mechanism 20 from a soil discharge port of the soil mixing and stirring mechanism 10 through a conveying belt, and is subjected to water adding and wet stirring pulping, so that the foamy slag soil and the heavy metal soil are fully and evenly mixed, and the primary elution reaction of the foamy on the heavy metal is carried out. The mixture after pulping is fed into a vibrating screen 311 by a lifting hopper for vibrating screening, the vibrating screen is a two-layer vibrating screen, a water spraying device is arranged, the mixture is washed while vibrating, and the separated sundries such as branches, plastics and the like and large-particle-size aggregates are washed to remove foaming agents and heavy metals remained on the mixture. The undersize material of the vibrating screen 311 after separation is conveyed into a rotary screen 321 by a screw feeder 71, and is screened and washed again, medium-diameter aggregate is screened out, and foaming agent and heavy metal remained on the screened-out material are removed. The undersize of the trommel 321 is fed from the screw feeder 72 into a cyclone 331 and a wheel type sand washer 332, further separating out fine aggregates in the slurry, and washing out foaming agent and heavy metal remaining on the fine aggregates. And pumping the separated slurry into a flocculation tank 41, adding a medicament, flocculating, precipitating and concentrating the slurry, feeding the supernatant into a first wastewater treatment device 50 for heavy metal removal treatment, feeding the concentrated solution into a plate-and-frame filter press 42 for further dehydration and drying, pumping the separated water phase into the first wastewater treatment device 50 for heavy metal removal treatment, and feeding the wastewater pump for heavy metal removal into a second wastewater treatment device 60 or a pulping mechanism 20 according to a mud cake detection result. The wastewater treated by the second wastewater treatment equipment 60 can reach the standard and be discharged or recycled for pulping water.

The foregoing is a further detailed description of the utility model in connection with specific preferred embodiments, and is not intended to limit the practice of the utility model to such description. It will be apparent to those skilled in the art that several simple deductions and substitutions can be made without departing from the spirit of the utility model, and these are considered to be within the scope of the utility model.

Claims

1. A system for treating heavy metal contaminated soil by using shield residue soil containing a foaming agent is characterized by comprising a soil mixing mechanism, a pulping mechanism, a particle separation mechanism, an elution mechanism, a first wastewater treatment mechanism for removing heavy metals and a second wastewater treatment mechanism for removing foaming agents, wherein a soil feed inlet of the pulping mechanism is communicated with a soil discharge outlet of the soil mixing mechanism, a water inlet of the pulping mechanism is communicated with a first water outlet of the first wastewater treatment mechanism and/or a water outlet of the second wastewater treatment mechanism, and a slurry outlet of the pulping mechanism is communicated with a feed inlet of the particle separation mechanism; the outlet of the particle separating mechanism is communicated with the feeding port of the eluting mechanism, the liquid outlet of the eluting mechanism is communicated with the water inlet of the first wastewater treatment mechanism, and the second water outlet of the first wastewater treatment mechanism is communicated with the water inlet of the second wastewater treatment mechanism.

2. The system for treating heavy metal contaminated soil with foaming agent shield muck according to claim 1, wherein the soil mixing mechanism comprises a shell, a soil feed inlet arranged at the front end of the shell, a soil discharge outlet arranged at the rear end of the shell and a spiral stirrer arranged in the shell.

3. The system for treating heavy metal contaminated soil with foaming agent shield muck according to claim 1, wherein the particle separating mechanism comprises a first separating unit for separating large-size sundries and large-particle-size aggregates, a second separating unit for separating medium-particle-size aggregates and a third separating unit for separating fine aggregates, a feed inlet of the first separating unit is communicated with a slurry outlet of the pulping mechanism, a discharge outlet of the first separating unit is communicated with a feed inlet of the second separating unit, a discharge outlet of the second separating unit is communicated with a feed inlet of the third separating unit, and a discharge outlet of the third separating unit is communicated with a feed inlet of the eluting mechanism.

4. A system for treating heavy metal contaminated soil with a foaming agent shield slag soil according to claim 3, wherein the first separation unit comprises a vibrating screen and a first flushing machine for cleaning oversize products of the vibrating screen, a feed inlet of the vibrating screen is communicated with a slurry outlet of the slurry making machine, an undersize product outlet of the vibrating screen is communicated with the second separation unit, a first oversize product and a first suspension are obtained after separation by the vibrating screen, the first oversize product is large-size sundries and large-size aggregates, and the first suspension enters the second separation unit through an undersize product outlet of the vibrating screen.

5. The system for treating heavy metal contaminated soil with foaming agent shield residue soil according to claim 4, wherein the second separation unit comprises a drum screen and a second flushing machine for cleaning oversize products of the drum screen, a feed inlet of the drum screen is communicated with an undersize outlet of the vibrating screen, an undersize outlet of the drum screen is communicated with the third separation unit, the second oversize products and a second suspension are obtained after separation by the drum screen, the second oversize products are medium-grain aggregate, and the second suspension enters the third separation unit through the undersize outlet of the drum screen.

6. The system for treating heavy metal contaminated soil with foaming agent shield slag soil according to claim 5, wherein the third separation unit comprises a cyclone and a wheel type sand washer which are communicated, wherein a feed inlet of the cyclone is communicated with an undersize outlet of the drum screen, a bottom flow port of the cyclone is communicated with a feed inlet of the wheel type sand washer, and an overflow port of the cyclone and a discharge port of the wheel type sand washer are communicated with a feed inlet of the elution mechanism.

7. The system for treating heavy metal contaminated soil with foamer-containing shield muck according to claim 1, wherein the elution mechanism comprises a flocculation tank and a plate and frame filter press, wherein a feed inlet of the flocculation tank is communicated with an outlet of the particle separating mechanism, a concentrate outlet of the flocculation tank is communicated with a feed inlet of the plate and frame filter press, and a supernatant outlet of the flocculation tank and a filtrate outlet of the plate and frame filter press are both communicated with a water inlet of the first wastewater treatment mechanism.

8. The system for treating heavy metal contaminated soil with foamer-containing shield muck of claim 7 wherein said elution mechanism further includes a doser in communication with a feed port of said flocculation tank for adding a flocculant to said flocculation tank.

9. The system for treating heavy metal contaminated soil with foamer shield muck of claim 6 further comprising a conveyor mechanism including a conveyor belt communicating the soil mixing mechanism with the slurrying mechanism, a hopper communicating the slurrying mechanism with the particle separating mechanism, a slurry pump communicating the particle separating mechanism with the elution mechanism, a first water pump communicating the elution mechanism with the first wastewater treatment mechanism, and a second water pump communicating the first wastewater treatment mechanism with the second wastewater treatment mechanism.

10. The system for treating heavy metal contaminated soil with foaming agent shield slag of claim 9, wherein said conveying mechanism further comprises a first spiral feeder in communication with said vibrating screen and said trommel, a second spiral feeder in communication with said trommel and said cyclone.