CN106216368B - One kind containing Cr6+Contaminated soil processing unit and its method - Google Patents

Abstract

The invention discloses a treatment device for contaminated soil containing Cr ⁶⁺ , comprising a wet vibration sorter, a hydrocyclone I, a mixer, a hydrocyclone II, and a vibration dehydration device; the wet vibration sorter passes through a conveying pipeline Connect with hydrocyclone I, said hydrocyclone I is connected with hydrocyclone II through mixer, hydrocyclone II is connected with vibrating dehydration device, both hydrocyclone I and hydrocyclone II pass sedimentation The tank is connected to the pressure filter; the vibration dehydration device is connected to the primary mixer and the secondary mixer in turn; the wet vibration sorter is connected to the supplementary water storage tank through a water pipe. Disclosed the treatment method of Cr ⁶⁺ contaminated soil, selected the composite technology of "soil washing + chemical reduction + fixation", adopted economical and effective soil purification conditions, and effectively realized soil purification.

Description

A device and method for treating Cr6+-contaminated soil

technical field

The invention belongs to the technical field of contaminated soil treatment, and in particular relates to a treatment device and method for contaminated soil containing Cr6 ⁺ .

Background technique

Due to rapid economic development and resulting industrialization, serious environmental pollution caused by various pollutants occurs. In particular, China has achieved rapid economic development starting from the 1990s, but the treatment and recycling of pollutants caused by industrial activities is not good.

The current trend of developed countries headed by the United States is to pass from the first-generation after-treatment technology to the second-generation pollution prevention technology, and recently enter the third-generation environmental purification technology, and invest in the purification and regeneration of polluted soil and groundwater. Huge financial and human resources, the global market for the purification of polluted soil and groundwater was 14.3 billion US dollars in 1994, 19.5 billion US dollars in 1998, and 23.7 billion US dollars in 2001. It is continuously increasing. On the contrary, compared with the seriousness of domestic soil and groundwater pollution, the development and actual field application of environmental purification technology is very insufficient, and the practical level of this technology is very low. Therefore, in order to protect the environment and maintain the health of the people, it is urgent to develop technologies for effectively purifying and restoring soil and groundwater contaminated by pollutants.

The source of soil pollution in China is that the by-products of industrial activities have not been properly treated, and the random discharge has caused the surrounding soil to be polluted or in a state of being polluted. In particular, when the pollutants contain a trace amount of heavy metals, continuous discharge will cause disturbance of the natural ecosystem predation chain, bioaccumulation, and human pathological phenomena or toxicity, causing problems. Among them, hexavalent chromium, a representative pollution source in China, is distributed in about 5 million tons of polluted soil in 21 regions.

As a relatively rare metal, chromium exists on average at about 100 ppm as a constituent element in the earth's crust, and at a concentration of 20 ppm in soil. The ore contains about 2-3000ppm of chromium, and the most widely used commercial source ores are chromite (chromite), chromite (FeCr ₂ O ₄ ) and the like. Surface and groundwater are polluted due to chromium flowing out from industrial activities into the environment, especially the main source of pollution is the pollution of chromium dissolved in silver metal mines. It has been reported that 84 μg/l of chromium was detected in surface water and 50 μg/l in groundwater (USEPA, 1987). Compared with trivalent chromium compounds such as chromium oxide (chromium trioxide, chrome green) and chromium hydroxide, hexavalent chromium compounds, namely chromic acid (chromium trioxide), chromate, dichromate, etc., are easy to penetrate The skin and mucous membranes have a great influence on the living body, and change into trivalent in the living body. Usually Cr ⁶⁺ compounds are more toxic than Cr ³⁺ compounds. The toxicity of chromium is mainly caused by Cr ⁶⁺ . Causes liver and kidney disorders, internal bleeding, respiratory disorders, and vomiting as acute symptoms. Because of the wide range of pollution and the large impact, it has long been a pollutant managed by various countries. The immobilization technology has a remarkable effect on the treatment of inorganic substances and radioactive substances, and it is generally applicable to the purification of areas polluted by non-halogen and halogen SVOCs. However, the purification effect of volatile organic pollutants, oil and gunpowder is not good, especially for the treatment of Cr ⁶⁺ contaminated soil. To deal with soil pollution, the most appropriate method should be selected according to natural and social conditions such as pollution degree, diffusion, geology, surrounding area conditions, and land use plans. Therefore, how to choose the purification technology according to the limitation of the applicable technology of pollutants has important practical significance.

Contents of the invention

Aiming at the technical problem of poor treatment effect of Cr ^{6+ -contaminated} soil existing in the prior art, the object of the present invention is to provide a treatment method for Gr ^{6 + -contaminated} soil.

The technical scheme that the present invention takes is:

A treatment device for contaminated soil containing Cr ⁶⁺ , comprising a wet vibration sorter, a hydrocyclone I, a mixer, a hydrocyclone II, and a vibration dehydration device; The hydrocyclone I is connected with the hydrocyclone II through the mixer, and the hydrocyclone II is connected with the vibration dehydration device. Both the hydrocyclone I and the hydrocyclone II pass through the sedimentation tank and pressure filtration machine connection; the vibration dehydration device is connected to the primary mixer and the secondary mixer in turn; the wet vibration sorting machine is connected to the supplementary water storage tank through a water pipe.

Further, the wet vibrating sorter is provided with a sieve plate, the upper surface of the sieve plate is set as a diamond-shaped screen, the lower intersection of the diamond-shaped screen is arranged in parallel with a partition tube, and the two sides of the sieve plate are provided with inclined baffles , the lower edge of the inclined baffle is provided with two rows of parallel and staggered spray holes, and the spray holes are connected with a high-pressure water pump through a water pipe.

Further, the continuous polluted soil first washing device composed of the wet vibration sorter and the hydrocyclone I; the continuous polluted soil second washing device composed of the mixer and the hydrocyclone II, the mixer There is a high-pressure jet pipe in it.

Further, the hydrocyclone I and the hydrocyclone II are equipped with eddy current detectors, and the tiny soil and sand below 3.0 mm are separated in particle size through the hydrocyclone, and the polluted micro soil and sand below 0.15 mm are separated from the polluted The wash water moves through the vortex detector of the hydrocyclone to the sedimentation and neutralization tank.

A method for processing contaminated soil containing ^Cr , specifically comprising the steps of:

(1) The first cleaning of soil: take the polluted soil, put it on the sieve plate of the wet vibrating sorting machine of the first soil washing device, spray and wash the polluted soil according to the volume ratio of polluted soil and water 1:3 liquid, and the mixed material is centrifuged through a hydrocyclone I to obtain soil I and waste water I containing pollutants;

(2) Soil 1 secondary washing: the soil 1 obtained by hydrocyclone 1 processing in step (1) is placed in the soil secondary washing device, according to the volume ratio of water and soil is 1:1, to the soil 1st Add water to the agitator of the secondary washing device, and add hydrochloric acid with 10 times the Cr6 ⁺ equivalent in the polluted soil at the same time, stir for 10-20min, and the mixed material is centrifuged through the hydrocyclone II to obtain the soil II and the contaminated substance. Wastewater II;

(3) Wastewater treatment: the waste water I obtained by step (1) hydrocyclone I treatment and the waste water II obtained by step (2) hydrocyclone II treatment are placed in the settling tank, and added with hydrochloric acid in the settling tank Add an equivalent amount of NaOH solution and ferrous sulfate with the same equivalent concentration of Cr ⁶⁺ in the polluted soil, precipitate for 2-2.5 hours, and filter the filtrate into a pressure filter to obtain treated water with a particle size of 0.075 Soil below mm;

(4) Soil II is stirred once: the soil II obtained by step (2) hydrocyclone II treatment is placed in a vibration dehydration device, and dehydration obtains soil III and waste water III containing pollutants, according to the volume ratio of water and soil. 1:4, add water to the soil in the vibration dehydration device, and add ferrous sulfate equivalent to 3 times the Cr ⁶⁺ in the polluted soil at the same time, and stir evenly for 0.5-0.8h;

(5) Soil II secondary stirring: in the soil III after stirring in step (4), according to the potassium phosphate of Cr ⁶⁺ equivalent 3 times in soil III, stir 0.5-0.8h, filter, obtain particle diameter and be 0.075mm- 3mm of decontaminated soil.

Further, in the step (1), the screening particle size of the wet vibrating sorter is 3.0 mm, the soil and sand below 3.0 mm are injected into the mixing and stirring device, and the gravel above 3.0 mm is separated into clean gravel and discharged.

Further, the waste water III obtained by processing in the step (4) is placed in the sedimentation tank, and the contaminated soil is added to the sedimentation tank with 5% NaOH equivalent to the dosage of hydrochloric acid and the contaminated soil Cr ⁶⁺ 5% of the equivalent concentration. % ferrous sulfate, precipitated for 2-2.5h, and the filtrate obtained by filtering was placed in a pressure filter for pressure filtration to obtain waste water with high pollution concentration and soil with a particle size below 0.075mm.

Further, the amount of HCl added in the step (2) is 10 times the equivalent of Cr in the ^polluted soil; the amount of NaOH added in the step (2) is equivalent to the amount of HCl added.

The beneficial effects of the present invention are:

When the washing technology in the present invention adopts sand and gravel whose optimal particle size of polluted soil is controlled at more than 0.25mm, the effect of washing technology can be brought into play to the greatest extent. Efficiency will be greatly improved.

The soil treatment process of the present invention regards economy and efficiency as the most suitable technology, and has selected the composite technology of "soil washing (3 times)+chemical reduction+fixation", and has selected the use of distilled water for soil washing as the reagent used in the technology , hydrogen chloride; chemical reduction using ferrous sulfate; chemical reduction: reducing hexavalent chromium to trivalent and then precipitated as hydroxide for removal. Acidifying agents such as sulfur or reducing agents such as Fe ²⁺ promote the reduction of Cr ⁶⁺ to Cr ³⁺ . The acidic state promotes the release of Fe ²⁺ from the soil to reduce Cr ⁶⁺ .

The invention firstly washes once with distilled water, then uses hydrochloric acid to reduce the pollution concentration, and at the same time has the effect of lowering the pH value. After the soil washing stage, ferrous sulfate was used to reduce to trivalent, and finally potassium phosphate product was used for immobilization technology. An economical and effective soil purification condition can be selected that not only meets the legal soil standard of 30mg/kg in China, but also saves costs.

After one wash with distilled water, another wash with hydrogen chloride was performed. After that, the chemical reduction technology using ferrous sulfate and the immobilization technology using potassium phosphate were carried out. The liquid-solid ratio of the contaminated soil to the solution was made 1:3, and the operation time was carried out in stages every 30 minutes. Using the results of the soil purification unit, the final hexavalent chromium concentration was lower than the Chinese legal standard of 30mg/kg.

The equipment adopted in the present invention is a structure of large-capacity equipment. Since the soil and sand produced after wet vibration sorting contains a large amount of washing water during the first washing, a vibrating dehydration device is installed to successfully separate it from the waste water. In the agitator of the secondary washing device, a settling tank, that is, a reaction tank, is additionally set up, thereby performing two washings to reduce pollutants; the first stirring and the second stirring do not use a batch method but a continuous project, so that Projects keep flowing during high-capacity processing.

It is beneficial to the operation of the project to store the small volume of washing water in one place before processing, but it is necessary to treat all the washing water and regenerate it when treating a large volume, so it should be supplemented by continuous engineering. The trough handles the fine soil and sand that flows in, while the fine soil and sand deposited in the lower part is removed with a solid-liquid separator. Redox tanks for treating hexavalent chromium wastewater are continuously installed so that removal can be performed at any time along the incoming water flow.

The treatment of hexavalent chromium in the washing water is carried out under acidic conditions, that is, the pH value is below 3. It is not necessary to add special chemicals. It is only necessary to mix the first washing water and the second washing water to adjust to acidic conditions. The cost of medicines needed to adjust the pH can be saved. Add ferrous sulfate in the reduction tank, and remove it in the precipitation tank after forming hydroxide in the neutralization tank. However, there may be a defect in equipment (adjusting the pH value to a strong alkalinity) in the neutralization tank, so the second stirring tank is installed to adjust the pH value again and then transferred to the sedimentation tank.

Description of drawings

Fig. 1 is a flow chart of the soil treatment process in the present invention.

1. Wet vibration sorting machine; 2. Hydrocyclone I; 3. Mixer; 4. Hydrocyclone II; 5. Vibration dehydration device; 6. Primary mixer; 7. Secondary mixer; 8. Sedimentation tank; 9. Filter press; 10. Supplementary water storage tank.

Detailed ways

Further illustrate the present invention below in conjunction with accompanying drawing.

Example 1

A treatment device for contaminated soil containing Cr ⁶⁺ , comprising a wet vibration sorter, a hydrocyclone I, a mixer, a hydrocyclone II, and a vibration dehydration device; The hydrocyclone I is connected with the hydrocyclone II through the mixer, and the hydrocyclone II is connected with the vibration dehydration device. Both the hydrocyclone I and the hydrocyclone II pass through the sedimentation tank and pressure filtration machine connection; the vibration dehydration device is connected to the primary mixer and the secondary mixer in turn; the wet vibration sorting machine is connected to the supplementary water storage tank through a water pipe.

The equipment adopted in the present invention is a structure of large-capacity equipment. Since the soil and sand produced after wet vibration sorting contains a large amount of washing water during the first washing, a vibrating dehydration device is installed to successfully separate it from the waste water. In the agitator of the secondary washing device, a settling tank, that is, a reaction tank, is additionally set up, thereby performing two washings to reduce pollutants; the first stirring and the second stirring do not use a batch method but a continuous project, so that During large-capacity treatment, the project remains downstream. When using sand and gravel with the optimum particle size of polluted soil controlled at 0.25 mm or more, the effect of washing technology can be maximized, and there are a large number of tiny silt and clay below 0.25 mm. , the washing efficiency will be greatly reduced.

Example 2

On the basis of embodiment 1, in the technical scheme of difference and embodiment 1, the continuous polluted soil washing device for the first time that above-mentioned wet vibrating sorting machine and hydrocyclone 1 are formed; Described agitator and hydrocyclone The continuous polluted soil secondary washing device composed of II, the mixer is equipped with a high-pressure air jet pipe, the soil to be washed and the HCl detergent are put into the hopper of the washing device together, and the pollutants, soil and sand are removed by physical mixing and chemical reaction. The washing water and polluted soil and sand are mixed in the wet vibrating sorter of the first washing device and transferred to the device, and the high-pressure air jet pipe is installed in the mixer of the second washing device for strong turbulent flow.

Example 3

On the basis of Example 1, different from the technical solution of Example 1, a sieve plate is arranged in the wet vibratory sorting machine, the upper surface of the sieve plate is set as a diamond-shaped screen, and the lower intersection of the diamond-shaped screen is arranged in parallel. There are inclined baffles on both sides of the sieve plate, and two rows of parallel and staggered spray holes are arranged on the lower edge of the inclined baffle. The spray holes are connected to the high-pressure water pump through water pipes. The structure setting of the diamond-shaped screen on the sieve plate and the structure of the baffle ensure that the granular material must be flatly attached to the screen surface and move along the screen surface when sieving, reducing the mis-screening rate and solving the problem of high mis-screening rate of granular materials and sieve failure. At the same time, it solves the problem that the vibration direction of the traditional vibrating screen is difficult to ensure the accuracy, thereby improving the screening efficiency.

Example 4

On the basis of embodiment 1, in the technical scheme that is different from embodiment 1, the above-mentioned hydrocyclone I and hydrocyclone II are provided with eddy current detectors, by affecting the slurry in the boundary layer on the outer surface of the logistics detector behavior to improve hydrocyclone performance. Separation of the boundary layer is induced such that fluid flow in the free edge region of the sidewall surface provides effective separation of overflow and boundary layer flow. The tiny soil and sand below 3.0mm are separated by particle size through the hydrocyclone, and the polluted micro soil and sand and polluted washing water below 0.15mm are moved to the sedimentation tank and neutralization tank through the eddy current detector of the hydrocyclone.

Example 5

As shown in Figure 1, a kind of containing Cr ^Contaminated soil processing method specifically comprises the following steps:

(1) The first cleaning of soil: take the polluted soil, put it on the sieve plate of the wet vibrating sorting machine of the first soil washing device, spray and wash the polluted soil according to the volume ratio of polluted soil and water 1:3 liquid, the mixed material is centrifuged through a hydrocyclone I to obtain soil I and waste water I containing pollutants;

In the step (1), the screening particle size of the wet vibrating sorter is 3.0 mm, the soil and sand below 3.0 mm are injected into the mixing device, and the gravel above 3.0 mm is separated into clean gravel and discharged.

(2) Soil 1 secondary washing: the soil 1 obtained by hydrocyclone 1 processing in step (1) is placed in the soil secondary washing device, according to the volume ratio of water and soil is 1:1, to the soil 1st Add water to the mixer of the secondary washing device, and at the same time add hydrochloric acid 10 times the equivalent of Cr ⁶⁺ in the polluted soil, and stir for 10 minutes. The mixed material is centrifuged through the hydrocyclone II to obtain soil II and waste water II containing pollutants. ;

The addition of HCl in the described step (2) is 10 times of ^Cr equivalent in the polluted soil; The addition of NaOH in the step (2) is suitable with the addition of HCl.

(3) Wastewater treatment: the waste water I obtained by step (1) hydrocyclone I treatment and the waste water II obtained by step (2) hydrocyclone II treatment are placed in the settling tank, and added with hydrochloric acid in the settling tank Add an equivalent amount of NaOH solution and ferrous sulfate with the same equivalent concentration of Cr ⁶⁺ in the polluted soil, precipitate for 2 hours, and filter the obtained filtrate into a filter press to obtain treated water and particles with a particle size below 0.075mm. soil;

(4) Soil II is stirred once: the soil II obtained by step (2) hydrocyclone II treatment is placed in a vibration dehydration device, and dehydration obtains soil III and waste water III containing pollutants, according to the volume ratio of water and soil. 1:4, add water to the soil in the vibrating dehydration device, and add ferrous ^sulfate equivalent to 3 times of Cr in the polluted soil at the same time, and stir evenly for 0.5h;

The waste water III that is processed in the described step (4) is placed in the settling tank, adds the 5% NaOH that polluted soil is equivalent to the hydrochloric acid dosage and polluted soil Cr 5% ^sulfuric acid of equivalent concentration in the settling tank The ferrous iron is precipitated for 2 hours, and the filtrate obtained by filtering is placed in a filter press for pressure filtration to obtain waste water with a high pollution concentration and soil with a particle size below 0.075mm.

(5) Soil II secondary stirring: in the soil III after stirring in the step (4), according to the potassium phosphate of Cr in soil III ⁶⁺ equivalent 3 times, stir 0.5h, filter, obtain particle diameter and be 0.075mm-3mm Purify the soil.

Example 6

As shown in Figure 1, a kind of containing Cr ^Contaminated soil processing method specifically comprises the following steps:

(1) The first cleaning of soil: take the polluted soil, put it on the sieve plate of the wet vibrating sorting machine of the first soil washing device, spray and wash the polluted soil according to the volume ratio of polluted soil and water 1:3 liquid, the mixed material is centrifuged through a hydrocyclone I to obtain soil I and waste water I containing pollutants;

In the step (1), the screening particle size of the wet vibrating sorter is 3.0 mm, the soil and sand below 3.0 mm are injected into the mixing device, and the gravel above 3.0 mm is separated into clean gravel and discharged.

(2) Soil 1 secondary washing: the soil 1 obtained by hydrocyclone 1 processing in step (1) is placed in the soil secondary washing device, according to the volume ratio of water and soil is 1:1, to the soil 1st Add water to the mixer of the secondary washing device, and at the same time add hydrochloric acid 10 times the equivalent of Cr ⁶⁺ in the polluted soil, and stir for 20 minutes. The mixed material is centrifuged through the hydrocyclone II to obtain soil II and waste water II containing pollutants. ;

The addition of HCl in the described step (2) is 10 times of ^Cr equivalent in the polluted soil; The addition of NaOH in the step (2) is suitable with the addition of HCl.

(3) Wastewater treatment: the waste water I obtained by step (1) hydrocyclone I treatment and the waste water II obtained by step (2) hydrocyclone II treatment are placed in the settling tank, and added with hydrochloric acid in the settling tank Add an equivalent amount of NaOH solution and ferrous sulfate with the same equivalent concentration of Cr ⁶⁺ in the polluted soil, precipitate for 2.5 hours, and filter the filtrate into a pressure filter to obtain treated water and particle size below 0.075mm Soil;

(4) Soil II is stirred once: the soil II obtained by step (2) hydrocyclone II treatment is placed in a vibration dehydration device, and dehydration obtains soil III and waste water III containing pollutants, according to the volume ratio of water and soil. 1:4, add water to the soil in the vibration dehydration device, and add ferrous sulfate equivalent to 3 times the Cr ⁶⁺ in the polluted soil at the same time, and stir evenly for 0.5-0.8h;

The waste water III that is processed in the described step (4) is placed in the settling tank, adds the 5% NaOH that polluted soil is equivalent to the hydrochloric acid dosage and polluted soil Cr 5% ^sulfuric acid of equivalent concentration in the settling tank Ferrous iron, precipitated for 2.5 hours, and the filtered filtrate was placed in a pressure filter for pressure filtration to obtain waste water with high pollution concentration and soil with a particle size below 0.075mm.

(5) Secondary stirring of soil II: in the soil III after stirring in step (4), according to the potassium phosphate of Cr in soil III ⁶⁺ equivalent 3 times, stir 0.8h, filter, and obtain particle diameter and be 0.075mm-3mm Purify the soil.

Pilot test results

For this test, hexavalent chromium-contaminated soil artificially polluted with potassium dichromate to a concentration of about 500mg/kg was used, and a pilot-scale continuous soil purification device was applied on-site. The summary of the experimental results is as follows.

After washing once with distilled water, it was washed once more with hydrochloric acid (HCl). After that, the chemical reduction technology using ferrous sulfate and the immobilization technology using potassium phosphate were carried out. The liquid-solid ratio of the contaminated soil to the solution was made 1:3, and the operation time was carried out in stages every 30 minutes. Using the results of the soil purification unit, the final concentration of hexavalent chromium was 14.83 mg/kg, thus complying with the legal standard of 30 mg/kg in China.

mass balance

Based on the field application results of the pilot-scale continuous soil purification device, the mass balance is set, but the initial concentration is about 489 mg/kg, which is the same as the measurement result, in order to clarify the removal and movement of pollutants present in 1 ton of soil and implemented.

The above is not a limitation of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the essential scope of the present invention, some changes, modifications, additions or substitutions can also be made, these Improvements and retouches should also be considered within the protection scope of the present invention.

Claims (8)

1. one kind contains Cr⁶⁺Contaminated soil processing method, which is characterized in that specifically comprise the following steps:

(1) soil cleans for the first time: take contaminated soil, be placed on the sieve plate of wet vibration grading machine, according to contaminated soil and The volume ratio 1:3 of water, to contaminated soil spray washing, mixed material is centrifuged by hydrocyclone I, obtains soil I and waste water I containing polluter；

(2) soil I secondary washing: the soil I that hydrocyclone I is handled in step (1) is placed into blender, according to The volume ratio of water and soil is 1:1, water is added into blender, while adding according to Cr in contaminated soil⁶⁺The salt that 10 times of equivalent Acid stirs 10-20min, and mixed material is centrifuged by hydrocyclone II, obtains soil II and containing polluter Waste water II；

(3) wastewater treatment: by step (1) hydrocyclone I the waste water I handled and step (2) hydrocyclone II processing Obtained waste water II is sequentially placed in reduction cell, neutralization chamber and precipitation tank, and Cr in contaminated soil is added in reduction cell⁶⁺It is identical Centinormal 1 ferrous sulfate, in neutralization chamber addition with the comparable NaOH solution of hydrochloric acid dosage, formed hydroxide after It is removed in precipitation tank, precipitates 2-2.5h, the filtrate being obtained by filtration is placed into filters pressing in filter press, obtain that treated water and partial size For 0.075mm soil below；

(4) soil II is once stirred: step (2) hydrocyclone II soil II handled is placed into vibration dehydrating device In, dehydration obtains soil III and the waste water III containing polluter, is 1:4 according to the volume ratio of water and soil, is dehydrated to vibration Soil in device adds water, while adding according to Cr in contaminated soil⁶⁺The ferrous sulfate that 3 times of equivalent, uniform stirring 0.5- 0.8h；

(5) soil II secondary agitation: in the soil III in step (4) after stirring, according to Cr in soil III⁶⁺The phosphorus that 3 times of equivalent Sour potassium, stirs 0.5-0.8h, and filtering obtains the purification soil that partial size is 0.075mm-3mm.

2. a kind of according to claim 1 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that wet type in the step (1) The screening partial size for vibrating grading machine is 3.0mm, and 3.0mm native sand below is injected into mixed stirring device, the gravel of 3.0mm or more Stone is separated into peace and quiet gravel discharge.

3. a kind of according to claim 1 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that processing in the step (4) Obtained waste water III is sequentially placed in reduction cell, neutralization chamber and precipitation tank, addition and contaminated soil Cr in reduction cell⁶⁺Phase When centinormal 1 5% ferrous sulfate, the NaOH with hydrochloric acid dosage comparable 5% is added in neutralization chamber, forms hydroxide It is removed in precipitation tank after object, precipitates 2-2.5h, the filtrate being obtained by filtration is placed into filters pressing in filter press, obtains high pollution concentration Waste water and partial size be 0.075mm soil below.

4. a kind of according to claim 1 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that HCl in the step (2) Additional amount be contaminated soil in Cr⁶⁺10 times of equivalent.

5. a kind of according to claim 1 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that used to contain Cr⁶⁺Pollution Soil treatment device, including wet vibration grading machine, hydrocyclone I, blender, hydrocyclone II, vibration dehydrating device； The wet vibration grading machine is connected by conveyance conduit with hydrocyclone I, and the hydrocyclone I passes through blender and water The II connection of power cyclone, hydrocyclone II are connected with vibration dehydrating device, and hydrocyclone I and hydrocyclone II pass through Precipitation tank is connected with filter press；The vibration dehydrating device is sequentially connected a blender and secondary mixer；The wet type vibration Dynamic grading machine is connected by water pipe with supplement water storage tank.

6. a kind of according to claim 5 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that the wet vibration sorts Sieve plate is provided in machine, sieve plate upper surface is set as diamond shape sieve, and the lower section intersection position of diamond shape sieve is arranged in parallel with every hole Pipe, sieve plate two sides are provided with tilting baffle, and the lower edge of tilting baffle is provided with two rows of spray apertures being staggered in parallel, Spray apertures are connected by water pipe with high-pressure hydraulic pump.

7. a kind of according to claim 5 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that the wet vibration sorts The continous way contaminated soil first time wash mill of machine and hydrocyclone I composition；The blender and hydrocyclone II group At second of wash mill of continous way contaminated soil, be provided with high pressure spray tracheae in blender.

8. a kind of according to claim 5 contain Gr⁶⁺Contaminated soil processing method, which is characterized in that the hydrocyclone I and Vortex finder is provided in hydrocyclone II, 3.0mm small soil below is husky to carry out partial size separation by hydrocyclone, The small soil of 0.15mm pollution below is husky to be moved in precipitation tank with pollution washing water by the vortex finder of hydrocyclone.