JP2003251330A - Washing equipment for oil polluted soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To take out soil particles low in oil content by efficiently classifying soil contained in a slurry formed by adding water to polluted soil, and to circu late the slurry during treatment and treated water to utilize them. <P>SOLUTION: Polluted soil containing oil is mixed with treated water under stirring in a washing apparatus 1 to form a slurry and an oil component is peeled off from soil. The soil lumps in the slurry are disintegrated by the jet streams from a disintegration spray 3 in the front stage of a wet vibration sieve 2 and treated water is ejected on the large particle component of soil from a washing spray 4 in the rear stage of the wet vibration sieve 2 to remove the oil component adhering to the large particle component. On the other hand, the slurry containing soil particles falls in a minus sieve slurry tank 6 to be adjusted in concentration by the slurry during treatment and this slurry is efficiently classified by a primary cyclone 10. The slurry containing fine particles is transferred to wastewater treatment equipment 27. The fine particles in the slurry are brought into slide contact with the wall surface of the cyclone or mutually rubbed to peel off the oil component on the surfaces of the fine particles. Thereafter, the fine particles in the slurry are again classified and washed in a secondary cyclone 18. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an oil which is treated by adding water to soil contaminated with oil and washing by mixing and stirring to separate the soil having a reduced oil content into a slurry containing the oil and treating the soil. Contaminated soil cleaning equipment

[0002]

2. Description of the Related Art In recent years, soil pollution by various pollutants generated by industrial activities has become a problem. Particularly, the work of purifying and removing contaminated soil with oil is one of the most important tasks in environmental maintenance projects, and the development of economical and efficient purification means is desired.

As a method for purifying oil-contaminated soil, the following methods are generally adopted. Supplying contaminated soil and water or cleaning agent to a rotary cleaning device such as a drum cleaning machine or drum screen, mixing and stirring these to form a slurry, contact friction of soil particles and cleaning effect of water or cleaning agent The oil is separated from the soil particles by and. Then, by a classifying device such as a sieve device or a cyclone, coarse particles of the soil in the slurry are separated, and the slurry containing the fine particles of the soil is conveyed to a storage tank and allowed to stand, and the oil is floated and removed. . Further, the fine-grained portion of the soil settled in the storage tank contains a large amount of oil and is treated as industrial waste after being dehydrated.

On the other hand, oil also adheres to the coarse particles separated from the slurry. This is because the oil that was once separated from the contaminated soil particles in the cleaning device is contained in the cleaning water and redeposits on the surface of the soil particles after cleaning. The oil content is likely to be redeposited when the operation is performed. The washed oil adheres to the surface area of the soil particles, and the finer the particle content, the higher the content of the contaminated oil. Therefore, when the large-grain portion and the coarse-grain portion in the soil are separated from the slurry that has been washed as described above, rewashing is necessary according to the particle size.

For example, in the device disclosed in Japanese Patent Laid-Open No. 2000-202422, two rotary sieving devices are arranged in series, contaminated soil is supplied to the rotary sieving device in the preceding stage, and a cleaning agent is sprayed from the upper part of the drum. Is rotated, and the contaminated soil and the cleaning agent are mixed and stirred to remove oil from the soil particles. Then, the coarse-grained portion of the soil is supplied to the rotary sieving device in the subsequent stage, and is finished and washed with fresh water to remove the oil content attached to the surface of the soil.
On the other hand, the wash water containing fine grains of the soil that has passed through the sieve mesh is collected in a collection tank and solid-liquid separated. The separated solid content is transferred to the subsequent process, and the liquid containing the cleaning agent is sprayed again on the rotary sieving device in the previous stage and is used again.

[0006]

However, the above conventional techniques have the following problems to be solved. A large amount of water is required because water is added to the contaminated soil to form a slurry, which is washed in a washing device and then the classified coarse particles are washed again. Considering the securing of used water and the final treatment, it is desirable to use as little water as possible. For example, Japanese Patent Laid-Open No. 2000-202422
In the device described in the publication, the coarse particles distributed by the first rotary sieve are washed with fresh water, and the amount of water used increases. Therefore, in order to reduce the amount of water used and the load on the wastewater treatment facility, it is necessary to effectively circulate the water used in the treatment system.

On the other hand, in the soil mixed and stirred with water or a detergent, the oil content varies depending on the particle size of the soil particles. Generally, the smaller the particle size, the higher the oil content. Therefore, after removing the coarse particles, the fine particles become industrial waste containing oil, but it is necessary to keep this amount as small as possible. For this purpose, it is desirable that the soil particles to be removed from the slurry as coarse particles be effectively washed to have a particle diameter as small as possible to reduce the oil content for separation. The coarse particles having a low oil content after washing can be backfilled in the original ground.

On the other hand, Japanese Patent Laid-Open No. 2000-202422
In the apparatus described in the publication, the slurry containing the oil content that has passed through the rotary sieving apparatus is subjected to solid-liquid separation processing, and the amount of soil separated with the oil content increases. That is,
In the sieving device, if the mesh size is smaller than about 200 μm to 300 μm, clogging occurs, so it is difficult to remove oil from soil particles having a smaller particle size and classify the soil particles. Further, even if the slurry that has passed through the sieve mesh is appropriately classified by another classifying device such as a cyclone, if the oil content in the coarse particle portion is relatively high, it cannot be backfilled as it is.

The present invention has been made in view of the above circumstances, and an object thereof is to efficiently classify soil contained in a slurry formed by adding water to contaminated soil to obtain an oil content ratio. It is to take out a small amount of soil particles and effectively circulate the treated slurry and treated water to reduce the amount of water used.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is to wash the soil while adding water to the oil-contaminated soil to stir and mix to form a slurry. A washing device, the slurry is supplied, a vibrating sieve that removes a large particle size component from the slurry, and a cyclone that separates coarse and fine particles of soil contained in the slurry that has passed through the vibrating screen, A slurry containing fine particles separated by the cyclone is provided with a wastewater treatment device for removing fine particles of soil and oil adhering thereto, and the vibrating screen is a part of the slurry that has passed through the vibrating screen. A crushing spray for spraying the slurry on the sieve in the front stage of the vibrating sieve, and a treatment spray for injecting the treated water treated by the wastewater treatment device to the soil particles remaining on the sieve in the latter stage of the vibrating sieve. There is provided an oil-contaminated soil washing installation, characterized in that it comprises a laser.

The soil polluted with oil is slurried in the above-mentioned washing device, the soil particles are rubbed together, and the oil adhering to the particles is peeled off. The slurry is sent to the vibrating screen, and the slurry that has passed through the vibrating screen from the crushing spray is jetted into the slurry at the front stage of the vibrating screen. As a result, the lumps of soil contained in the slurry are crushed without using make-up water, only the large particle size contained in the soil remains on the sieve, and the slurry containing the coarse and fine particles is sieved. Pass through the eyes. Then, the soil particles on the sieve move to the latter stage of the vibrating sieve, the treated water from which the oil content has been removed is jetted from the cleaning spray, and the oil content that has reattached to the surface of the soil particle is washed away and removed. This treated water is obtained by removing coarse particles of soil with a cyclone from the slurry that has passed through the sieve mesh, and further purifying the slurry containing fine particles with a wastewater treatment device.By using this treated water, ,
Soil particles can be washed and clean soil particles can be removed from the vibrating screen. As described above, a large amount of circulating slurry is used for crushing, and a small amount of wash water is used for large-sized soil particles having a relatively low pollutant concentration, whereby the amount of fresh water used can be greatly reduced.

According to a second aspect of the present invention, there is provided a cleaning device for adding water to an oil-contaminated soil, stirring and mixing the mixture to form a slurry, and for cleaning the soil, and supplying the slurry to a large particle. A vibrating sieve to remove the diameter, a cyclone that separates the coarse and fine particles of soil contained in the slurry that has passed through the vibrating sieve, and a slurry containing the fine particles separated by the cyclone,
It is provided with a wastewater treatment device for removing fine particles of soil and oil adhering to it, and a part of the overwater of the cyclone is refluxed to the slurry supplied to the cyclone, and the slurry introduced into the cyclone. It is intended to provide an oil-contaminated soil cleaning facility characterized by adjusting the concentration.

Generally, when the concentration of the slurry supplied to the cyclone is high, the fluidity of the slurry is lowered and the slurry stays inside the cyclone. Then, the soil particles in the slurry are not satisfactorily classified, and the coarse particles of the soil may flow out to the overwater side. On the other hand, with a slurry containing a large amount of water, the classification efficiency due to the cyclone will be reduced. In the oil-contaminated soil cleaning equipment, a part of the overwater of the cyclone is returned to the slurry supplied to the cyclone, and the amount of this reflux is adjusted to adjust the concentration of the slurry introduced into the cyclone. As a result, a slurry having a constant concentration can be stably supplied to the cyclone without newly adding new water, and the coarse and fine particles of soil contained in the slurry can be well separated. Then, the slurry from which the coarse particles have been removed can be clarified by removing the fine particles and the oil adhering thereto in the wastewater treatment device.

According to a third aspect of the present invention, there is provided a cleaning device for adding water to soil contaminated with oil, stirring and mixing the mixture to form a slurry, and for cleaning the soil, and the slurry is supplied from the slurry to obtain large particles. A vibrating sieve to remove the diameter, a cyclone that separates the coarse and fine particles of soil contained in the slurry that has passed through the vibrating sieve, and a slurry containing the fine particles separated by the cyclone,
A wastewater treatment device for removing fine particles of soil and oil adhering thereto is provided, wherein the cyclone includes two cyclones, the underwater of the first cyclone, the treated water treated by the wastewater treatment device. The present invention provides a device for cleaning oil-contaminated soil, characterized in that the slurry whose concentration is adjusted by adding to the second cyclone is supplied.

The slurry that has passed through the vibrating screen is separated by a first cyclone into coarse particles and fine particles of soil contained in the slurry, and the slurry containing the coarse particles is discharged as underwater. Fine particles are contained in the overwater of the cyclone and discharged. At this time, the coarse particles are rubbed against the wall surface of the cyclone, or the particles are rubbed with each other, so that the oil particles attached to the surfaces of the particles are peeled off. And
The separated oil is sent to the wastewater treatment equipment together with the overwater. Slurry containing oil and fine particles is solid-liquid separated by a wastewater treatment device, the treated water from which oil and fine particles of soil have been removed, part of which is added to the underwater of the first cyclone, After adjusting the concentration, the slurry is fed to the second cyclone. This allows
The slurry does not stay in the second cyclone, the particles in the slurry are again rubbed against the wall surface of the cyclone, the particles are rubbed against each other, and rewashed. Therefore, soil particles having a low oil content can be taken out as the underwater of the second cyclone.

In general, a cyclone having a large diameter can classify a large amount of water, and at the same time, the size of classification becomes large. On the other hand, a small-diameter cyclone can only classify a small amount of water, but it has a characteristic that the classification size becomes small. As an example of classification using this characteristic, Japanese Patent Laid-Open No. 9-3365
In Japanese Patent No. 13, the overwater of the cyclone is sequentially supplied in series to a cyclone having a small diameter.

However, according to the invention of this claim, the soil particles in the fluid introduced into the cyclone at a high speed are brought into strong contact with the wall surface of the cyclone by the centrifugal force and are rubbed and rubbed against the wall surface. Focusing on the occurrence of rubbing between soil particles, classification is performed with a cyclone and the cleaning effect is used. That is, the underwater of the first cyclone is introduced into the second cyclone to repeat the washing, and the contaminated oil is separated from the coarse particles of the soil and removed together with the overwater.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an oil-contaminated soil cleaning facility that is an embodiment of the invention according to claim 1, claim 2, or claim 3. This oil-contaminated soil cleaning equipment mixes and stirs the contaminated soil to which oil adheres with the cleaning water supplied from the cleaning water line 28 to form a slurry, and a cleaning device 1 for cleaning the soil, and the slurry to the soil. The wet vibrating screen 2 for removing the contained coarse gravel and the like 5, the sub-sieving slurry tank 6 into which the slurry passed through the screen of the wet vibrating screen 2 is charged, and the slurry supplied from the sub-sieve slurry tank 6 Included in the primary cyclone 10 for classifying into a slurry containing coarse and fine particles of soil, a primary coarse particle tank 14 for storing underwater of the primary cyclone 10, and a slurry supplied from the primary coarse particle tank 14. A secondary cyclone 18 for classifying the soil and washing coarse particles of the soil, and a secondary coarse particle tank 21 for solid-liquid separation of the underwater of the secondary cyclone 10.
And a wastewater treatment facility 27 for purifying the overwater of the primary cyclone 10 and the overwater of the secondary cyclone 18 constitute a main part.

As the cleaning device 1, for example, a drum washer can be used. This drum washer supports a drum-shaped container so that its axis line is horizontal or slightly inclined, and is driven to rotate around the axis line to mix and stir the stored soil and wash water. By mixing and stirring, the soil particles collide with each other and are rubbed against each other, so that the oil is separated from the soil particles. The contaminated soil is introduced from one end in the axial direction, is slowly conveyed in the axial direction as it rotates, and is discharged from the other end.

A two-stage vibrating screen is used as the wet vibrating screen 2, and a crushing spray 3 for injecting the slurry supplied from the under-sieving slurry tank 6 is provided in front of the wet vibrating screen.
Further, the cleaning spray 4 for injecting the treated water supplied from the wastewater treatment facility 27 is provided at the latter stage. Then, while vibrating the sieve screen, the lump of soil contained in the slurry on the sieve screen is crushed by the injection from the crushing spray 3 in the preceding stage of the vibrating screen, and the large particle size of the soil and the soil Separate the slurry containing the coarse and fine particles. Further, in the latter stage of the vibrating screen, the treated water is sprayed from the cleaning spray 4 to the large particle size portion of the soil remaining on the screen to remove the oil component reattached to the large particle size portion.

The above-mentioned under-sieving slurry tank 6 stores the slurry that has passed through the screen of the wet vibrating screen 2, and includes a stirrer 7 for stirring the slurry, a pump 8 for supplying the slurry to the crushing spray 3, A pump 9 that supplies the primary cyclone 10, a concentration transmitter 31 that measures the concentration of the slurry in the undersize slurry tank and outputs a detection signal, and a liquid level transmitter that detects the liquid level of the slurry and outputs the detection signal. And 34.

The stirrer 7 stirs the slurry by, for example, a blade-shaped or screw-shaped stirrer that is driven to rotate, and prevents the soil particles contained in the stored slurry from accumulating.

The concentration transmitter 31 measures the concentration of the slurry in the slurry storage tank and inputs the measured value to the concentration controller 32 as an electric signal. Concentration controller 32
Has an appropriate concentration set in advance, and the set value is compared with the measured value. The opening and closing of the control valve 33 is adjusted based on the result of this comparison. This allows
The amount of slurry that is recirculated from the circulation overline 11 to the under-sieving slurry tank 6 is adjusted, and the slurry in the under-sieving slurry tank 6 is adjusted to an appropriate concentration.

As the liquid level transmitter 34, a non-contact type detector using ultrasonic waves or laser is used. The upper limit value and the lower limit value of the liquid level height of the slurry are set in advance in the liquid level transmitter 34, and it is detected that the liquid level of the slurry has reached the upper limit value or the lower limit value. . When the liquid level reaches the upper limit value or the lower limit value, a control signal is output to the adjusting valve 33, and the opening / closing of the adjusting valve 33 is adjusted when this signal is input. Thereby, the under-slurry slurry tank 6 from the circulation overline 11
The amount of slurry that is refluxed into the tank is adjusted,
The liquid level height of the slurry is controlled.

A wet cyclone is used as the primary cyclone 10, and a slurry containing fine particles and oil having a small mass is sent to a circulation overline 11 or a drainage overline 12 from a discharge port 10a provided at the top. . On the other hand, the slurry containing the coarse particles having a large mass,
From the outlet 10b provided at the bottom to the underline 13
After that, it is discharged to the primary coarse grain tank 14.

The primary coarse-grain tank 14 is a wastewater treatment facility 27.
The treated water and the slurry in the tank supplied from the stirrer 15
Stir to dilute the slurry. The slurry whose concentration is adjusted in the primary coarse particle tank has improved fluidity, and the slurry is less likely to stay in the secondary cyclone.

The secondary cyclone 18 is a wet cyclone having the same classification points as the primary cyclone 10.
The secondary cyclone 18 is supplied with the slurry from the primary coarse particle tank 14 by the pump 16, and the soil particles in the slurry are rubbed against the wall surface of the secondary cyclone 18 or the soil particles are rubbed with each other to form the surface of the particles. The oil adhered to is peeled off. From the discharge port 18b at the bottom of the secondary cyclone 18, coarse particles having a large mass are discharged into the secondary coarse particle tank 21,
From the discharge port 18a at the top, the overwater containing the oil separated from the soil particles and the fine particles in the slurry not separated by the primary cyclone 10 is discharged to the wastewater treatment facility 27.

The secondary coarse grain tank 21 is buried in a semi-underground, and a partition net 22 and a submersible pump 23 are provided in the tank. The partition net 22 separates the input slurry into coarse particles and water, and the water is the water pump 2.
3 is to be transferred to the wastewater treatment facility 27.

The wastewater treatment facility 27 is for removing the oil contained in the slurry by floating it, and for sedimenting and dehydrating the fine grain portion to which the oil is reattached to produce a contaminated cake. On the other hand, the treated water from which the fine particles and the oil have been removed is refluxed to the cleaning device 1, the cleaning spray 4, and the secondary coarse particle tank 14.

Next, the operation of this oil-contaminated soil cleaning equipment will be described. Contaminated soil with oil attached to the cleaning device 1,
Wash water is introduced from the wash water line 28, and mixed and stirred. The contaminated soil becomes a slurry, and the oil content is separated from the soil by collision and rubbing between the soil particles accompanying mixing and stirring, and the oil is sent to the wet vibrating screen 2. In the former stage of the wet vibrating screen 2, the lump of soil contained in the slurry on the screen is crushed by the spray from the crushing spray 3, and the slurry containing the particles of the soil passes through the screen by the vibration of the screen. It falls into the under-sieving slurry tank 6. On the other hand, the large particle size of the soil moves to the latter stage of the vibrating screen, the treated water is sprayed from the cleaning spray 4, the oil content adhering to the large particle size is removed, and it is carried out of the system.

In the under-sieving slurry tank 6, the concentration of the slurry is measured by the concentration transmitter 31, and the opening / closing of the control valve 33 is adjusted. As a result, the amount of slurry sent from the wastewater overline 12 to the wastewater treatment facility 27 and the amount of slurry recirculated from the circulation overline 11 to the slurry storage tank 6 are adjusted, and the slurry concentration is adjusted. The slurry is supplied to the primary cyclone 10 by the pump 9, and a part of the slurry is supplied to the crushing spray 3 by the pump 8 for circulation.

The slurry fed into the primary cyclone 10 has its concentration adjusted, and is efficiently classified into a slurry containing fine particles and a coarse particle. At this time, the coarse particle is rubbed against the wall surface of the cyclone. Alternatively, the particles are rubbed against each other, and the oil component attached to the surface of the particles is peeled off. The slurry containing the fine particles and the separated oil is sent to the circulation overline 11 or the drainage overline 12, and the coarse particles are discharged to the primary coarse particle tank 14. Circulation overline 1
The slurry sent to No. 1 is again supplied to the under-sieving slurry storage tank 6, and the slurry sent to the drainage overline 12 is transferred to the wastewater treatment facility 27.

In the primary coarse particle tank 14, the coarse particles in the primary coarse particle tank and the treated water supplied from the waste water treatment facility 27 are mixed by the stirrer 15, and a slurry containing the coarse particles whose concentration has been adjusted is mixed. It is sent to the next cyclone 18. In the secondary cyclone 18, since the concentration of the slurry is adjusted, the slurry is mixed and stirred without staying, the particles of the soil are rubbed against the wall surface of the cyclone again, and the particles of the soil are rubbed against each other and the oil adhering to the surface is washed away. Therefore, coarse particles having a low oil content are discharged to the secondary coarse particle tank 21. The fine particles remaining in the slurry are transferred to the wastewater treatment facility 27 via the overline 19.

In the secondary coarse grain tank 21, the coarse mesh portion and the moisture are separated by the partition net 22, and the moisture is sent to the wastewater treatment facility 27 by the submersible pump 23 for treatment. on the other hand,
Most of the oil in the coarse particles has been removed by a cyclone and it can be backfilled as it is. In the wastewater treatment facility 27, the oil content contained in the slurry is floated and removed, and the fine grain content of the soil containing a large amount of oil is sedimented and dehydrated to form a contaminated cake, which is then transported out of the system as industrial waste. On the other hand, the treated water from which oil and fine particles of soil have been removed is recirculated to the cleaning device 1, the cleaning spray 4 and the secondary coarse particle tank 14 to save water.

In the above process, the concentration of the slurry in the under-sieving slurry tank 6 is adjusted by the control valve 33, and the liquid level height varies. However, when the liquid level reaches the upper limit value or the lower limit value, the liquid level height is controlled as follows.
When the liquid level transmitter 34 detects that the liquid level of the slurry has reached the upper limit value, it is input to the control valve 33 as an electric signal, and the control valve 12 is closed. Then, the slurry containing fine particles, which is the overwater of the primary cyclone, is entirely sent to the wastewater treatment facility 27 through the wastewater overline 12. On the other hand, when the liquid level decreases to the lower limit value, the control valve 33 is opened by the input from the liquid level transmitter 34, and the amount of the slurry recirculated from the circulation overline 11 to the undersize slurry tank 6 becomes the maximum. As a result, the liquid level height of the slurry in the under-sieve slurry tank 6 is maintained within the range between the upper limit value and the lower limit value.

When the cleaning experiment of the contaminated soil was carried out using this oil-contaminated soil cleaning equipment, the following results were obtained. 30 tons of original soil 17 tons / h contaminated with 3% oil content
The water content was adjusted to%, and the mixture was stirred and mixed with a drum washing machine for 10 minutes to form a slurry, which was put into a two-stage wet vibrating screen. As shown in FIG. 2, this vibrating screen has a 5 mm screen 41a in the upper stage,
1 mm sieve net 41b in the lower stage, crushing spray 42 facing the former stage sieve net 41a and sieve net 41b, and the latter stage sieve net 4
A cleaning spray 43 is provided so as to face the lamina 1a and the screen 41b. The treated water is jetted from the crushing spray 42 onto the sieve net 41a and the sieve net 41b in the front stage of the vibrating screen, and the treated water is jetted into the soil remaining on the sieve net 41a and the sieve net 41b from the washing spray in the latter stage, The upper soil was discharged to the conveyors 44a and 44b. As a result, the oil content in the washed soil of 1 mm or more was 3000 ppm. Further, the oil discharged from the slurry discharge unit 45 contained in the slurry having a particle size of 30 μm to 1 mm and adhering to soil particles of 5000 ppm, and the other oil was contained in the slurry containing fine particles of 30 μm or less.

A slurry containing soil particles of 1 mm or less is
After adjusting the particle concentration to 12%, the particles were fed to a primary cyclone having a classification point of 30 μm to separate fine particles and coarse particles contained in the slurry. The slurry containing coarse particles with a supply flow rate ratio of 15% was adjusted to a particle concentration of 12% by adding diluted treatment water from drainage treatment, and then supplied again to a secondary cyclone having a classification point of 30 μm, The grain was washed. As a result, the oil content of the underwater of the secondary cyclone became 1000 ppm.

The soil particles of 30 μm or less contained in the contaminated soil treated by this equipment were 10% of the total soil, but when the particle size distribution of the contaminated soil was biased to fine grains,
If you want to further reduce the cake that is carried out of the system as industrial waste, you can achieve the purpose by arranging multiple cyclones with small classification points connected in parallel in series.

[0039]

As described above, according to the oil-contaminated soil cleaning equipment of the present invention, the soil contaminated with oil is made into slurry in the cleaning device, and the oil is separated from the soil particles. The slurry is sent to the vibrating screen, and the slurry being processed is sprayed in the front stage of the vibrating screen to crush the lumps of soil contained in the slurry on the screen, and to the large particle size of the soil that has moved to the rear stage of the vibrating screen. The treated water is jetted, and the oil component reattached to the large particle size is removed. As a result, the amount of water used can be greatly reduced and clean soil can be separated. The concentration of the slurry that has passed through the sieve mesh is adjusted by hydrolyzing part of the cyclone's overwater, and it is effectively classified into coarse and fine particles of soil without retaining in the cyclone. , The oil adhering to the surface of the soil particles is peeled off. Further, by providing a cyclone in series, adjusting the concentration of the underwater of the cyclone in the former stage, feeding it to the cyclone in the latter stage after adjusting the concentration, and rewashing, soil particles having a low oil content can be taken out.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an oil-contaminated soil cleaning facility that is an embodiment of the invention according to claim 1, claim 2, or claim 3.

FIG. 2 is a schematic configuration diagram of a wet vibrating screen that can be used in the oil-contaminated soil cleaning equipment shown in FIG.

[Explanation of symbols]

1 Cleaning device 21 Secondary coarse grain tank 2 Wet vibration sieve 22 Partition mesh 3 Crushing spray 23 Submersible pump 4 Cleaning spray 27 Wastewater treatment facility 5 Gravel etc. 28 Washing water line 6 Under-sieve slurry tank 30 Contaminated cake 7, 15 Stirrer 31 Concentration transmitter 8, 9, 16 Pump 32 Concentration controller 10 Primary cyclone 33 Control valve 11 Circulation overline 34 Liquid level transmitter 12 Drainage overline 13 underline 14 Primary coarse grain tank 18 Secondary Cyclone 19 Overline

Continued front page    (72) Inventor Akiko Hirai             3-18-5 Chugoku, Ichikawa, Chiba Sumitomo Metals             Central Research Laboratory, Mining Co., Ltd. (72) Inventor Ryozo Ushio             3-18-5 Chugoku, Ichikawa, Chiba Sumitomo Metals             Central Research Laboratory, Mining Co., Ltd. (72) Inventor Goro Ichikawa             3-1-10 Kuramae, Taito-ku, Tokyo Kuramae Cent             Larville 6F Sumicon Celtech Stock Association             In-house (72) Inventor Kenji Yamazaki             3-1-10 Kuramae, Taito-ku, Tokyo Kuramae Cent             Larville 6F Sumicon Celtech Stock Association             In-house F-term (reference) 4D004 AA41 AB02 AC05 CA10 CA12                       CA13 CA15 CA40 CB05 CB09                       CB13 CB21 CB26 CB50 CC03                       DA02 DA10 DA11 DA12                 4D071 AA05 AA53 AB14 AB48 CA01                       DA20

Claims (3)

[Claims] 1. A cleaning apparatus for water-mixing oil-contaminated soil with stirring and mixing to form a slurry, and for cleaning the soil, and a vibration to which the slurry is supplied to remove a large particle size from the slurry. Sieve, a cyclone for separating coarse particles and fine particles of soil contained in the slurry that has passed through the vibrating screen, and a slurry containing fine particles separated by the cyclone, fine particles of soil and this A waste water treatment device for removing oil adhering to the vibrating screen, wherein the vibrating screen is a crushing spray for spraying a part of the slurry that has passed through the vibrating screen to the slurry on the screen in the preceding stage of the vibrating screen, An oil-contaminated soil cleaning facility, comprising: a cleaning spray that sprays the treated water treated by the wastewater treatment device onto the soil particles remaining on the sieve in the latter stage of the vibrating sieve. 2. A cleaning apparatus for water-mixing oil-contaminated soil with stirring and mixing to form a slurry and for cleaning the soil, and a vibration for supplying the slurry to remove a large particle size portion from the slurry. Sieve, a cyclone for separating coarse particles and fine particles of soil contained in the slurry that has passed through the vibrating screen, and a slurry containing fine particles separated by the cyclone, fine particles of soil and this A wastewater treatment device for removing oil adhering to the cyclone, and a part of the overwater of the cyclone is refluxed to the slurry supplied to the cyclone, and the concentration of the slurry introduced into the cyclone is adjusted. Equipment for cleaning oil-contaminated soil. 3. A washing device for adding water to soil contaminated with oil to stir and mix to form a slurry and to wash the soil, and a vibration to which the slurry is supplied to remove a large particle size portion from the slurry. Sieve, a cyclone for separating coarse particles and fine particles of soil contained in the slurry that has passed through the vibrating screen, and a slurry containing fine particles separated by the cyclone, fine particles of soil and this And a cyclone, which comprises two cyclones, the underwater of the first cyclone, the treated water treated by the wastewater treatment device was added to adjust the concentration. The slurry,
An oil-contaminated soil cleaning device characterized by supplying to a second cyclone.