JPH10249325A - Treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely recover a chemical substance from the soil contg. the chemical substance such as org. solvent by classifying the soil based on the size of the clod to obtain a fraction contg. the concd. chemical substance, separating and recovering the chemical substance from the fraction. SOLUTION: A classifier 1 has a crushing part 2 and a classifying part 3, and the crushing part 2 is provided with a heating wire 4, a water content measuring sensor 5 and a controller 6. Two kinds of screens 7a and 7b are arranged in the classifying part 3 to classify the soil into three fractions. Sampling is conducted with respect to classification tanks 8a to 8c to investigate the preset content of the chemical substance. The fraction judged to be treated is then introduced into a rotary part 10 in a vessel 9 and heated, the vapor of the chemical substance discharged by an exhauster 11 is cooled in a cooler 13, liquefied and introduced into a purifier 14, and the chemical substance is recovered by the activated carbon 15a to 15c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment apparatus for recovering a chemical substance from soil containing a chemical substance such as a metal or an organic solvent, and more particularly, to a method for classifying soil and obtaining a fraction in which the chemical substance is concentrated. And a processing device for recovering a chemical substance from the fraction.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed as techniques for treating soil containing chemical substances such as heavy metals and organic solvents. For example, a method of excavating and discarding soil and replacing it with new soil, adding an additive to the excavated soil to form a heavy metal precipitate, or incorporating a heavy metal into the additive, Method of recovering substances or additives from soil, method of immobilizing heavy metals in soil with substances that insolubilize heavy metals such as cement, sodium sulfide or iron sulfate, or providing a water-blocking sheet in soil to prevent the diffusion of chemical substances Is the way. In addition, after wet washing the soil, the method of precipitating and filtering heavy metals dissolved in the washing solution and recovering them from the soil, and focusing on the fact that heavy metals in the soil are positively charged, using electrical energy, magnetic force, etc. Thus, a method of recovering heavy metals from soil has also been proposed.

[0003]

However, the above proposal has many problems.

[0004] That is, when excavating and discarding soil from the environment, the soil must be excavated over a wide area, and there has been a major problem in terms of treatment efficiency and cost. In addition, it is not easy to excavate from the environment without leaving any soil to be discarded, and a container for accommodating the excavated soil is required.Therefore, a disposal site must be secured or chemical substances leak from the disposal site into the environment. Monitoring the disposal site for a long period of time to check the impact on the environment has been a major problem in terms of cost. Furthermore, when additives are added to the soil, the effects of the additives on the environment must be considered, and the technology for immobilizing heavy metals and the like in the soil is still in the research stage, and Since there are few data that guarantee long-term immobilization of heavy metals, there is a problem that the acidity of soil changes due to the effects of acid rain and the risk that the immobilized heavy metals etc. elute into the groundwater system cannot be denied. Was. further,
There is a problem that a long-term evaluation of the durability of the water-impervious sheet has not been sufficiently obtained for the water-impervious sheet placed in the soil so that the chemical substance does not diffuse. In addition, since soil is generally negatively charged, it tends to easily adsorb positively charged heavy metals.Therefore, the method of wet-cleaning the soil and then precipitating and filtering the heavy metals dissolved in the washing solution is not used. However, there is a problem that it is difficult to completely remove heavy metals. In addition, methods using electric energy and magnetic force have been successful in recovering heavy metals and the like from soil, but mercury is highly unevenly distributed in soil,
In addition, since it is difficult to ionize due to the properties of mercury, there has been a problem that treatment with electric energy or magnetic force cannot be expected.

[0005] The present invention has been made in view of the above-mentioned conventional example, and is based on soil containing chemical substances such as metals and organic solvents.
It is an object of the present invention to provide a processing device that reliably recovers the chemical substance and is excellent in economy.

[0006]

According to a first aspect of the present invention, there is provided a treatment apparatus for classifying soil containing a chemical substance based on the size of soil particles to obtain a fraction enriched with the chemical substance. And means for separating the chemical substance from the obtained fraction, and means for collecting the separated chemical substance.

In the processing apparatus according to the first aspect of the present invention, by classifying soil containing a chemical substance based on the size of soil particles, it is possible to obtain a fraction enriched with the chemical substance. Since the separation and recovery of the chemical substance are performed from the fractionation, the chemical substance can be reliably recovered from the soil. Further, by obtaining a fraction enriched with a chemical substance, the volume of the soil to be treated can be reduced, so that the chemical substance can be economically recovered.

[0008] The processing apparatus according to the second invention of the present application includes:
Classifying the soil containing the chemical substance based on the sedimentation velocity of the soil particles, means for obtaining a fraction enriched with the chemical substance, means for separating the chemical substance from the obtained fraction, and the separated Means for recovering a chemical substance.

In the treatment apparatus according to the second aspect of the present invention, by classifying the soil containing the chemical substance based on the sedimentation velocity of the soil particles, a fraction enriched with the chemical substance can be obtained. Since the separation and recovery of the chemical substance are performed from the fractionation, the chemical substance can be reliably recovered from the soil. Further, by obtaining a fraction enriched with a chemical substance, the volume of the soil to be treated can be reduced, so that the chemical substance can be economically recovered.

Generally, soil is composed of a large number of soil particles. According to the International Soil Society Law, soil particles are classified as follows according to the particle diameter. That is, gravel (particles having a particle diameter of 2.0 mm or more), coarse sand (particles having a particle diameter of 2.0 to 0.2 mm)
), Fine sand (particles having a particle diameter of 0.2 to 0.02 mm), silt (particles having a particle diameter of 0.02 to 0.002 mm), and clay (particles having a particle diameter of 0.002 or less). The present inventors have a property that most of the chemical substances contained in the soil have a small particle size, specifically, a characteristic that the particle size is easily adsorbed to soil particles having a particle size of 75 μm or less,
The present invention has been made in view of the fact that 70 to 80% of the chemical substances contained in the soil are present together with the soil particles having the particle diameter. Normally, in water in soil, solutes dissociate into ions, and soil particles have a positive or negative charge on the surface. As for the charge amount, since the negative charge is about 10 times as large as the positive charge, the soil particles are negatively charged as a whole. There are two major mechanisms of charge generation. One is a 2: 1 type crystalline clay mineral represented by montmorillonite, and the Si ⁴⁺ in the silicic acid tetrahedral layer is Al ^3+.
This is a permanent charge that occurs when Al ^{3+ in} the alumina octahedral layer is replaced with Mg ²⁺ or Fe ²⁺ .
The other one is displacement charge caused by bonding of Si or Al generated on the end face of the clay mineral to a hydroxyl group, regardless of whether it is crystalline or non-crystalline. Displacement charge changes with pH.
Is higher, the load increases and the positive charge decreases. The displacement charge also changes depending on the ion concentration. As the ion concentration increases, both the positive and negative charges increase.
Therefore, by controlling the pH and ion concentration of the soil, the positive or negative charge generated on the surface of the soil particles can be adjusted.

In the soil, an electrostatic force acts between the charge generated by the above mechanism and the dissociated ions of the solute, so that a cation is adsorbed to a negative charge and an anion is adsorbed to a positive charge. Adsorbed on the surface of the particles. Note that the adsorption includes reversible adsorption, which is released when another kind of ion comes, and irreversible adsorption, in which the adsorption is so strong that almost no desorption occurs even when another kind of ion comes. The amount of cations adsorbed by soil is the sum of the amount of ions in the stern layer on the inner surface of the soil particles and the amount of ions in the diffusion double layer, but the thickness of the diffusion double layer indicates that the ion concentration is high. The higher the valence, the smaller the cation tends to be. It should be noted that negative adsorption or elimination of anions in the diffusion double layer is performed. When ions are adsorbed on the soil particles by electrostatic force, the adsorbed ions are desorbed when another kind of ion comes, and ion exchange occurs in which newly appearing ions are adsorbed instead. Ion exchange occurs because the adsorption force differs for each ion species, but also differs between ions of the same valence. For example, the adsorptivity of monovalent alkali cations is as follows.

Cs ⁺ > Rb ⁺ > K ⁺ > Na ⁺ > Li ^{+ The} larger the ionic radius, the smaller the number of water molecules attracting around the ions. This is because a strong electrostatic force acts between them.
In addition, between monovalent ions and divalent ions, divalent ions have stronger adsorption power.

[0013] The adsorptivity of anions is as follows.

SiO ₄ ^4- > PO ₃ ^3- > SO ₄ ^2- > Cl ⁻ > NO ₃ ⁻
Although it varies depending on the ion concentration and the type of clay mineral, if these factors are controlled, the ion species adsorbed on the surface of the soil particles can be exchanged.

As described above, it has a characteristic that it is easily adsorbed on soil particles having a particle size of 75 μm or less, and 70 to 80% of the chemical substances contained in the soil are present together with the soil particles having the particle size. Soil particles having a small diameter have a large surface area (surface area) where adsorption occurs. For example, 1g
The surface area of soil particles of sandy soil is several m ² , and that of clayey soil is
It shows 100 m ² , 500 m ^{2 for} bentonite and 810 m ² for montmorillonite. Therefore, it is considered that the adsorption by the above mechanism strongly acts on soil particles having a particle diameter of 75 μm or less, and the chemical substance can be concentrated by classifying the soil. Also, since mercury in soil often exists in the form of fine particles, it is considered that enrichment is possible by classifying the soil. Further, regarding the organic solvent, it is possible to consider a form in which the organic solvent is adsorbed on the clay, dissolved in an organic substance and absorbed in the clay, or buried in the soil particles like fly ash. Also tend to be concentrated into soil particles with a particle size of 75 μm or less,
Concentration is possible by classifying the soil.

In the first invention of the present application, the means for classifying soil containing a chemical substance on the basis of the size of soil particles and obtaining a fraction enriched with the chemical substance includes the steps of: For the purpose of breaking down the structure and performing classification based on the size of a single soil particle, apply physical vibration to the soil by ultrasonic waves, etc., or directly crush the soil, pass it through a filter, etc., or And a method of introducing vibration into a container to give vibration. When passing through the filter, the soil is classified according to the diameter of the filter. In addition, when vibration is applied to the container, the larger the particle size of the soil particles, the higher the level of the soil particles, and the larger the size of the soil particles, the lower the level of the container. The soil can be classified by taking out only the painting. As described above, most of the chemical substances in the soil are present together with the soil particles having a particle diameter of 75 μm or less. For example, after excavating the soil containing the chemical substance, the soil is crushed and passed through a filter. : 75 μm or less, B: 75 to 300 μm, C: 300 μm or more, the chemical substance will be concentrated in the fraction A. In the case of crushing the soil, it is preferable to heat the crushed soil to about 60 ° C. and evaporate the moisture in the soil, since the crushing of the aggregated structure is facilitated. Also, by heating the soil to about 60 ° C, it is expected that the organic solvent etc. contained in the soil will evaporate, so the generated steam is introduced into a filter etc., purified, and then released to the atmosphere. It is desirable. In this case, together with the classification of the soil, organic solvents having a low boiling point are separated from the soil,
It becomes possible to collect. In addition, for each fraction of the classified soil, for example, the above-mentioned fractions A to C, the content of each chemical substance was analyzed, and after confirming that the fraction A contained most of the chemical substances, The fraction in which the analysis value of the chemical substance is equal to or less than the environmental standard value is backfilled to the location before excavation. As described above, the fraction A is almost always contaminated with chemical substances higher than the environmental standard value.

Further, in the second invention of the present application, the soil containing the chemical substance is classified based on the sedimentation velocity of the soil particles,
As means for obtaining a fraction enriched in the chemical substance,
Forced fluidization of the soil in the fluid, the settling velocity of the soil particles,
In other words, means for classifying the soil using the difference in time during which the soil particles float in the fluid can be mentioned. When the soil is forcibly fluidized in the fluid, the aggregate structure is almost destroyed, and a single soil particle can be obtained. Here, the sedimentation speed of the particles in the viscous fluid can be calculated by the following equation.

V = 2 (ρ−ρ ₀ ) gr ² / 9η (where, v: sedimentation velocity, ρ: density of soil particles, ρ ₀ : density of medium, g: gravitational acceleration, r: sphere particles In other words, if the soil is forcibly fluidized in a fluid and the soil is left in a stationary fluid, the soil becomes as shown in the above equation. Since the particles settle in the fluid at each settling speed, a necessary fraction, for example, a soil particle having a particle size of 75 μm or less can be fractionated. In addition, by appropriately setting the flow of the fluid, for example, soil particles having a particle diameter of about 75 μm or less float in the fluid, while soil particles having a particle diameter of about 75 μm or less can be settled in the sedimentation fluid, By removing the settled soil particles from the fluid, the soil can be fractionated. For example, A: 75 μm or less, B: 75 to 300
If a fraction is obtained by classification based on the particle diameter of μm, C: 300 μ or more, the chemical substance will be concentrated together with the soil particles in the fraction A. As the fluid, various liquids and gases can be used, and destruction of the aggregated structure is facilitated. For example, a dry gas such as dry air can be used. Generally, soil particles such as sand have a water content of about
Since the water permeability is about 20% to 30% and the coefficient of water permeability is large, the rate at which chemical substances such as heavy metals stay in the surfaces of the soil particles or in the gaps between the soil particles for a long time is low.
On the other hand, soil particles such as silt and clay having a small particle diameter have a smaller permeability than sand and gravel, and water stays in the stratum for a long time. In particular, the water content of clay can reach 80% or more, so removing moisture from the soil will weaken the cohesion between the soil particles.
In addition, chemical substances such as mercury that exist in the form of fine particles in the soil contact the soil with a dry gas, thereby weakening the binding properties of silt or clay having an aggregated structure. It can be easily separated from the particles. In addition, other metals except mercury are often ionized and exist in soil, but chemicals with a large surface tension, such as mercury, are liquid at room temperature and easily form fine particles even in soil. . In addition, compounds containing mercury have extremely low solubility products except for sulfides and the like, and are difficult to bond with other ions. Therefore, by using a dry gas to weaken the bonding force of the soil particles such as silt and clay, the soil particles and the fine particles such as mercury scattered in the aggregate structure are easily taken out from the soil. The classification may be performed while heating the dry air to about 60 ° C. to evaporate the moisture in the soil. By heating the dry air, the efficiency of removing moisture from the soil increases, but on the other hand, it is also expected that the organic solvent etc. contained in the soil will evaporate.
As described above, it is desirable that the generated steam is introduced into a filter or the like and purified, and then released to the atmosphere. Thus, it is possible to separate and collect an organic solvent having a low boiling point from the soil together with the classification of the soil. . In addition, fractions whose chemical analysis values are less than or equal to environmental standards can be backfilled to the location before excavation.

In the first and second inventions of the present application, the means for separating a chemical substance from the obtained fraction includes controlling the temperature and pressure around the fraction to obtain a characteristic of the chemical substance to be separated. Means for separating a chemical substance from the obtained fraction. For example,
By reducing the pressure around the obtained fraction and increasing the temperature, specific chemical substances can be separated.

In general, the relationship between vapor pressure and temperature can be expressed by a simple Clapeyron-Clausius equation.

Ln (P / Pa) = A− (B / (T / K)) − ClnT (where, P: pressure (Pa), A, B, C: constant depending on the substance, T: temperature ( K)) For example, if the target of separation from the obtained fraction is mercury, A = 29.19, B = 7710,
Since C = 0.84, when this is substituted into the above equation, the vaporization temperature of mercury at a pressure of 1 torr is 400 k, and the pressure is 10 ^-3 to
The vaporization temperature of mercury at rr is 293k. The boiling point of mercury is 629.58k.
It is possible to vaporize mercury by raising the temperature up to the boiling point of mercury under atmospheric pressure, but lowering the processing temperature by lowering the pressure is less costly and easier to operate than raising the temperature to the boiling point of mercury under atmospheric pressure. Become. That is, by lowering the pressure around the fraction, the chemicals vaporize at a temperature lower than the boiling point under atmospheric pressure, so chemicals such as organic solvents and heavy metals, especially chemicals that are liquid at room temperature such as mercury Can be vaporized with extremely high efficiency, and the temperature control becomes easy. Specifically, by heating the fraction in a closed container close to a vacuum to selectively vaporize a metal having a high vapor pressure, as will be described later, to collect the metal precipitated by cooling again, Since the boiling point of the metal is reduced in vacuum, high-purity metals at temperatures much lower than the boiling point at normal pressure, for example, metals such as Zn, Pb, Cd, Sb, Se, Te, and Sr can be respectively recovered. Separation and recovery of metal is changed by evaporating metal by changing the pressure and temperature inside the closed vessel,
And by preparing a cooling recovery container for each evaporated metal,
It can be easily implemented. If the separation target is mercury, the optimal processing conditions are to set the temperature around the fraction to 320-37.
5k, pressure should be adjusted to 10 ^-1 to 10 ^-2 torr.

Further, as a means for separating a chemical substance from the obtained fraction, vibrations are applied to the obtained fraction from the outside by ultrasonic waves or high-frequency waves to further weaken the bond between soil particles, Means for removing a chemical substance such as a metal adhered or adsorbed on the surface of the substrate. In particular, metals such as mercury have a higher specific gravity than the obtained soil particles in the fraction, and thus can be easily separated from the fraction. In addition, other metal compounds and the like adsorbed on the soil particles in the fractionation are ionized by, for example, mixing water vapor or the like into the surrounding atmosphere, and trapped inside the water vapor, thereby trapping the soil in the fractionation. Can be separated from particles. Further, there may be mentioned means for performing a chemical treatment on the fraction. For example, adding a chelating agent to the obtained fraction to trap metals,
An organic solvent or the like can be separated by extraction with a solvent. In addition, when separating mercury from fractionation,
After being converted to mercury oxide by heating at 500 ° C. or lower, mercury oxide can be converted to potassium mercury iodide by adding an aqueous solution of potassium iodide and separated as mercuric iodide ions. The reaction formula is shown below.

Hg + 1 / 2O ₂ → HgO HgO + 4KI + H ₂ O → K ₂ HgI ₄ + 2KOH K ₂ HgI ₄ → 2K ⁺ + HgI ₄ ^{2- In} addition, mercury is in the form of mercury iodide ion.
As will be described later, electrical processing can be performed. here,
The case where mercury is separated from the fraction will be described in detail below.

The heating of the fractionated soil is carried out for the purpose of oxidizing the particulate mercury present in the fraction and converting it to oxidized mercury. Care must be taken not to volatilize and diffuse into the atmosphere. Therefore, in heating the obtained fraction, the heating temperature is preferably in a range in which the volatilization and diffusion of mercury are suppressed, and the generation of mercury oxide is sufficiently fast, and is in a temperature range of 100 ° C to 500 ° C. Is preferred. Further, it is more preferable that the temperature range is from 300 ° C to 400 ° C. The reason is that when the temperature is lower than the above temperature, the oxidation takes place at a very slow rate because the oxidation rate of mercury is extremely slow. This is because the decomposition rate of mercury sharply increases the volatilization rate of mercury, so that the danger of diffusion into the atmosphere increases dramatically.
In heating the fraction, the heating method is not particularly limited, but various known heating devices can be used. For example, a rod-shaped or plate-shaped electric heater or the like may be buried inside the fraction and heated, or it is more preferable that the fraction is stirred simultaneously by a rotary kiln or the like. During heating, make sure that the volatilized mercury does not diffuse into the atmosphere.
Preferably, the fraction to be treated is covered with a sealing sheet. Next, after cooling the fraction after heating to 100 ° C. or lower, by adding an aqueous solution of potassium iodide, as shown in the above chemical formula, the generated mercury oxide is ionized as mercury potassium iodide. As is clear from the above chemical formula, potassium iodide requires a mole number of at least 4 times the stoichiometric amount with respect to the total amount of mercury in the fractionation. Further, when the fractionation is actually treated, it is preferable to further add an aqueous solution containing potassium iodide having a molar number several times or more the molar number required stoichiometrically. In addition, when mercury is separated based on the above reaction formula, it is preferable to use the classified fraction because the volume of soil required for the treatment can be reduced, but it can also be performed on-site, When mercury is separated on-site based on the above reaction formula, it is preferable to cover the fraction to be treated with a sealing sheet so that the volatilized mercury does not diffuse into the atmosphere.
When an aqueous solution of potassium iodide is added, it is preferable to provide a water impermeable wall in advance to the water-impermeable layer so that the mercury compound does not diffuse into the environment.

Further, in the first and second aspects of the present invention, as means for recovering the separated chemical substance, for example, the pressure around the obtained fraction is reduced and the temperature is raised to increase the specific chemical substance. Is separated, the vapor containing the metal is cooled to recover the metal, the vapor containing the chemical substance is trapped by an adsorbent such as activated carbon, and the vapor containing the chemical substance is converted into a chelate resin. And a chemical substance can be selectively adsorbed in the matrix. Also, by applying vibration energy to the fraction from the outside by ultrasonic or high frequency, even if chemical substances such as metal adhering or adsorbing on the surface of soil particles are separated, the activated carbon or chelating agent can Can be taken, and in the case of containing ionized metal or the like trapped in water vapor,
Chemical substances trapped in activated carbon or chelating agents can be adsorbed. Further, when mercury is to be collected and mercury is chemically ionized as described above, mercury can be collected by electrical treatment. That is, an electric field is generated in a fraction or soil containing ionized mercury, and ionized mercury can be concentrated and recovered according to the electric field. Specifically, for example, an anode and a cathode connected via a DC power supply and an electric circuit are installed in the fractionation or in the soil to flow a DC current, and a negatively charged mercury iodide ion is generated around the anode by electric energy. To concentrate. The method for collecting and removing the concentrated mercury is not particularly limited, and a known method can be appropriately used. Further, mercury in the fractionation or in the soil is concentrated near the anode, so that it is easy to simply excavate and remove the soil. In addition, as is clear from Nernst's equation, the migration of not only mercury iodide ions but also other metal ions and metal-containing ions largely depends on the fractionation or soil pH. In the case of the transfer of mercury iodide ions, mercury can be collected and collected in the vicinity of the anode or the anode particularly by supplying water to the anode and optimizing the fractionation or the pH of the soil. In other words, by adjusting the fraction or the pH of the soil, it is also possible to adjust the metal species collected and collected near the electrode. When mercuric iodide ions generated by the above reaction formula are electrically recovered, the pH of the fraction or soil becomes alkaline with potassium hydroxide. Dilute potassium hydroxide with a low concentration hardly impacts the soil or the environment.However, it can be made alkaline by washing with water or, if necessary, adding acidic substances such as carbon dioxide, diluted sulfuric acid, and diluted hydrochloric acid. Sloped soil may be neutralized.
In particular, care must be taken during on-site neutralization so as not to impose a burden on the environment.

In the first and second aspects of the present invention, the chemical substances include metals such as mercury, gold and platinum contained in soil, copper, cadmium, chromium, aluminum, and the like.
It is a general term for substances such as metal compounds including zinc, lead, iron, nickel, arsenic, tin and uranium, and organic solvents such as trichloroethylene (TCE), and their existence forms are not limited at all.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description of each drawing is omitted.

FIG. 1 is a diagram schematically showing the configuration of a processing apparatus according to the present invention.

In FIG. 1, a classification device 1 has a crushing section 2 and a classification section 3. The crushing section 2 has a diameter of 1 m, a depth of 0.8 m, and a stamp having a bottom which can be automatically opened and closed. Mill. The crushing unit 2 includes a heating wire 4 arranged around the
The internal temperature is maintained at about 60 ° C. by the moisture measuring sensor 5 and the control device 6 which controls the heating wire 4 and the moisture measuring sensor 5, and the moisture of the soil in the crushing unit 2 is reduced.
It is controlled to execute the process until it becomes 0-5%. When the soil introduced into the crushing unit 2 is dried and crushed, the bottom of the crushing unit 2 is automatically opened, and the soil is categorized into the classification unit 3.
Move to. 300 μm or more, 300-75μ
Two types of sieves 7a and 7b are arranged so that the soil is classified by three types of particle diameters of m and 75 μm or less, and three fractions can be obtained. The soil introduced into the classification unit 3 is passed through two sieves while being subjected to constant vibration, so that a classification tank 8c provided with a fraction A having a particle diameter of 300 μm or more as a main component, Is 300-75μ
a classification tank 8b provided with a fraction B containing m soil particles as a main component,
The particles are classified into a classification tank 8a provided with a fraction C mainly composed of soil particles having a particle diameter of 75 μm or less. Usually, classification tanks 8a to 8
Each sampling is performed from c, and the content of a predetermined chemical substance is checked. Fractions below the environmental standard value for all of the set chemical substances do not require further processing, and can be used for backfilling or reclaiming at the excavated site. As described above, chemical substances in soil, for example, various metals such as mercury, metal compounds, organic solvents, and the like tend to be concentrated in a fraction having a particle diameter of 75 μm or less as a main component of soil particles. Therefore, usually, a fraction 8 mainly composed of soil particles having a particle diameter of 75 μm or less is used.
By treating C, most of the chemical substances in the soil can be separated and recovered. The fraction determined to be necessary to be processed by the above-described investigation, for example, the fraction C mainly composed of soil particles having a particle diameter of 75 μm or less is subsequently charged into the rotatable rotary unit 10 inside the container 9. You. Container 9
The pressure inside the container 9 can be maintained at a reduced pressure. An adjusting unit 12 for controlling is provided. And the temperature inside the container 9 is 300 to 1000
k, pressure can be adjusted in the range of 760-10 ^-6 torr. Therefore, for example, when the temperature inside the container 9 is increased under the atmospheric pressure,
By increasing the temperature to 629.58k, mercury can be vaporized. It is economical and easy to operate. The rotation speed of the rotary unit 10 can be adjusted within a range of 10 to 30 rpm, and can be appropriately adjusted based on the amount of soil particles to be processed in the container 9 and the processing speed. Further, the exhaust device 11 is controlled so that the generated steam can be exhausted from the container 9 to the purifier 14 via the cooler 13 without affecting the pressure in the container 9. The vapor of the chemical substance exhausted by the exhaust device 11 is cooled and liquefied by the cooler 13 adjusted to about 10 ° C., and then introduced into the purifier 14. And the chemical substance contained in the steam is collected by the activated carbons 15a to 15c. Here, activated carbon 1
Each of 5a to 15c is divided into three types, one for an organic solvent, one for a heavy metal, and one for mercury, so that it is possible to collect different chemical substances. When separating and collecting a plurality of metals, the container 9
Change the metal to evaporate by changing the pressure and temperature inside,
If a cooler 13 and a purifier 14 are prepared for each metal and steam is introduced, separation and recovery of a plurality of metals can be easily performed. As described above, according to the processing apparatus shown in FIG. 1, it is possible to efficiently and safely collect chemical substances such as metals, metal compounds, and organic solvents from soil. In addition, by setting the optimum conditions for the chemical substance to be collected based on the simple formula of Clapeyron-Clausius, regardless of the type of chemical substance,
The chemical substance can be efficiently recovered from the soil.
Further, since the volume of soil requiring treatment can be reduced and the treatment temperature can be kept low, chemical substances such as metals, metal compounds or organic solvents can be economically recovered from soil.

FIG. 2 is a diagram schematically showing the configuration of another processing apparatus according to the present invention. In FIG. 2, the soil introduced into the inlet 17 is approximately
When the dried air at 100 ° C. is sucked into the flowing inclined tube 19, it is introduced so as to diffuse into the separation layer 20. In the separation layer 20, the soil introduced from the inclined pipe 19 is substantially dissociated into soil particles, and a distribution occurs at a height that rises in the separation layer 20 due to the density and particle diameter of the soil particles. That is, since the soil sent into the separation layer 20 together with the dry air rises in the inclined pipe 19 having the inclination, the soil is diffused from the outlet of the inclined pipe 19 into the space of the separation tank 20 and, at the same time, almost draws a parabola. Start exercising. At this time, gravel and sand with a large particle diameter continue to move at a speed close to free fall after reaching the top, but silt and clay with a small particle diameter are separated by controlling the flow of dry air. You will float in 20 spaces. Therefore, the lower part of the separation tank 20 is provided with a waste duct 21 for collecting particles having a large particle diameter such as gravel and sand having a large particle diameter, while the upper part of the separation tank 20 is provided with a silt having a small particle diameter. A suction duct 22 and a suction duct 23 capable of sucking soil particles such as clay and clay are provided to separate soil particles having a small particle diameter. Particle size of gravel and sand with large particle size is almost 300μ
m or more, it can be returned to the excavated area again or used for landfill. By the conveyor 24 arranged together with the waste duct 21, gravel, sand having a large particle diameter, and the like are reliably discharged from the separation tank 20 to the outside.
The soil particles supplied from the suction duct 22 and the suction duct 23 to the vibration tank 25 are generated by the vibration device 26 and have a frequency of
Vibration energy is given by the vibration of the 25000 Hz ultrasonic wave, weakening the bond between the slightly remaining soil particles while moving from the vibration tank 25 to the sedimentation tank 27, and the metal and the like adhering to the surface of the soil particles. Peel off the chemicals. In particular, since mercury has a high surface tension and a strong tendency to form fine particles having a small particle diameter even in soil, it is highly effective to apply vibrational energy to discharge mercury particles from the inside of the soil particles. Among the particles that have passed through the vibration tank 25, metals such as mercury have a higher specific gravity than soil particles, and therefore, when they pass through a fluid, sedimentation is fast. Therefore, by disposing an adsorbent 28 mainly composed of an inimidiaacetic acid type chelate resin in a stage preceding the settling tank 27, mercury can be selectively adsorbed and recovered. The metal or metal complex which is ionized and present in the soil particles is described in the vibration tank 2.
5 is trapped in water vapor by introducing steam and the like, and organic solvents and the like are trapped in a non-polar solvent by introducing a non-polar solvent etc. Separation / recovery can be performed by arranging and adsorbing the components. Then, the soil particles from which the chemical substance has been recovered can be moved to an excavated point, a landfill site, or the like after processing such as dehydration. As described above, according to the processing apparatus shown in FIG. 2, it is possible to efficiently and safely collect chemical substances such as metals, metal compounds, and organic solvents from soil. In addition, by setting the type of the fluid, the direction of the flow, the velocity of the flow, and the like so as to be optimal conditions for the chemical substance to be collected, the chemical substance is removed from the soil regardless of the type of the chemical substance. It can be collected efficiently. Further, since the volume of the soil requiring treatment can be reduced and the treatment temperature can be kept low, it is possible to economically recover chemical substances such as metals, metal compounds or organic solvents from the soil. In addition, when the soil is excavated, it becomes easy to bury the excavated soil at the original point.

FIG. 3 is a diagram schematically showing the configuration of another processing apparatus according to the present invention. The processing device shown in FIG. 3 is different from the processing device shown in FIG. 2 in that the vibration device 26 is replaced with a remote control device 2 connected to an external power supply (not shown).
Generator 3 connected to 9 and remote control 29
The difference is that 0 is provided.

In the processing apparatus shown in FIG. 3, the soil particles supplied from the suction duct 22 and the suction duct 23 to the vibrating tank 25 are generated by the high frequency generator 30 using an AC 200V power supply and have a frequency of 30,000 Hz. Vibration energy is given by high-frequency vibration, and weakening of the bond between the slightly remaining soil particles while moving from the vibration tank 25 to the sedimentation tank 27, and the removal of chemical substances such as metals adhering to the surface of the soil particles. Peel off. Then, by disposing an adsorbent 28 having an inomidiacetate-type chelate resin as a base in the preceding stage of the sedimentation tank 27, for example, mercury can be selectively adsorbed and recovered. The metal or metal complex which is ionized and present in the soil particles is trapped in the water vapor by introducing water vapor or the like into the vibration tank 25 as described above. By introducing a non-polar solvent or the like into the tank 25, the trap is trapped in the non-polar solvent, and activated carbon or the like is placed and adsorbed in the settling tank 27 to perform separation / recovery. And
The soil particles from which the chemical substances have been recovered can be moved to a digging point, a landfill site, or the like after a treatment such as dehydration.
As described above, according to the processing apparatus shown in FIG. 3, it is possible to efficiently and safely recover chemical substances such as metals, metal compounds, and organic solvents from soil. In addition, by setting the type of the fluid, the direction of the flow, the velocity of the flow, and the like so as to be optimal conditions for the chemical substance to be collected, the chemical substance is removed from the soil regardless of the type of the chemical substance. It can be collected efficiently. Further, since the volume of the soil requiring treatment can be reduced and the treatment temperature can be kept low, it is possible to economically recover chemical substances such as metals, metal compounds or organic solvents from the soil.
In addition, when the soil is excavated, it becomes easy to bury the excavated soil at the original point.

FIG. 4 is a diagram schematically showing the configuration of another processing apparatus according to the present invention. In FIG.
The soil introduced from the inlet 31 into the separation tank 32 is held by the filter 33 and flows from the lower part to the upper part in the separation tank 32 by the dry air of about 100 ° C. sent from the blower 34. The soil rising from the lower part to the upper part in the separation tank 32 is separated from the separation tank 32 by dry air.
It is dissociated to almost soil particles by diffusing inside, and distribution occurs at a position in the separation tank 32 depending on the density and particle diameter of the soil particles. That is, gravel, sand with a large particle diameter, etc.
The fine particles such as silt and clay move to the upper part of the separation tank 32 by the dry air and drift there. That is, the soil has a particle diameter of, for example, 300 in the separation tank 32.
Fraction 35c mainly composed of soil particles of μm or more, having a particle diameter of
It is classified into a fraction 35b mainly composed of soil particles of 300 to 75 μm and a fraction 35a having a particle diameter of 75 μm or less. Note that the flow rate of the dry air sent from the blower 34 can be controlled by a control valve 36. Then, from the fraction 35a transferred to the upper part of the separation tank 32, earth particles such as silt or clay having a small particle diameter flow into the vibration tank 38 through the discharge pipe 37.
In addition, since the particle diameter of the gravel and the sand having a large particle diameter in the fractions 35b and 35c is about 300 μm or more, it can be returned to the excavated area or used for landfill. The soil particles supplied to the vibration tank 38 through the discharge pipe 37 are given vibration energy by the vibration of the ultrasonic wave having a frequency of 25000 Hz generated by the vibration device 26, and
After weakening the bond between the soil particles slightly remaining in 5 and removing the chemical substance such as metal adhering to the surface of the soil particles, it is introduced into the sedimentation tank 40 through the discharge pipe 39. On the other hand, the air containing the soil particles having a large particle diameter is returned to the separation tank 32 through the recovery pipe 41. By the way, since mercury has a large surface tension and has a strong tendency to form fine particles having a small particle size even in soil, it is highly effective to apply vibrational energy for the purpose of discharging mercury particles from the inside of the soil particles. Then, for example, mercury can be selectively adsorbed and recovered by the adsorbent 28 having an inomidiacetate-type chelate resin as a base disposed in the preceding stage of the settling tank 40.
The soil from which the chemical substances have been removed is collected in the collection tank 43 by opening and closing the collection valve 42. The metal or metal complex which is ionized and present in the soil particles is trapped in the steam by introducing steam or the like into the vibration tank 38 through the introduction pipe 44, and the organic solvent or the like is trapped in the vibration tank. By introducing a non-polar solvent or the like into 38, trapping in the non-polar solvent and separation and recovery can be performed by arranging and adsorbing activated carbon or the like in the settling tank 40. Then, the soil particles from which the chemical substance has been recovered can be moved to an excavated point, a landfill site, or the like after processing such as dehydration. As described above, according to the processing apparatus shown in FIG. 4, it is possible to efficiently and safely recover chemical substances such as metals, metal compounds, and organic solvents from soil. In addition, by setting the type of the fluid, the direction of the flow, the velocity of the flow, and the like so as to be optimal conditions for the chemical substance to be collected, regardless of the type of the chemical substance,
The chemical substance can be efficiently recovered from the soil.
Further, since the volume of the soil requiring treatment can be reduced and the treatment temperature can be kept low, it is possible to economically recover chemical substances such as metals, metal compounds or organic solvents from the soil. In addition, when the soil is excavated, it becomes easy to bury the excavated soil at the original point.

FIG. 5 is a diagram schematically showing the configuration of another processing apparatus according to the present invention. In FIG. 5A, the classification device 1 is the same as that shown in FIG. 1, and after examining the fractions classified by the classification device 1, a fraction determined to require processing, for example, a particle size The fraction composed of soil particles having a particle size of 75 μm or less is introduced into the treatment tank 45,
6 by sheath heaters 47a and 47b connected to
Heat to 100-500 ° C. Then, by heat treatment,
An aqueous solution containing potassium iodide is added to the fraction that has produced mercury oxide (HgO), and an electric current is supplied to an anode 49 and a cathode 50 connected to a DC power supply 48, as shown in FIG. Is shed. Mercury iodide ions generated during the fractionation are concentrated and collected in the anode 49 and its vicinity according to the electric current. The heating of the fraction can be performed by the sheath heaters 47a and 47b, and the entire fraction can be uniformly heated. For example, the fraction can be heated using a rotary kiln. Further, in FIG.
And by supplying water around the cathode 50, the fraction 8a
Can be maintained at a constant pH to increase the transfer efficiency of mercury iodide ions. As described above, according to the processing apparatus shown in FIG. 5, it is possible to efficiently and safely collect chemical substances composed of metals such as mercury, gold, and platinum from soil. Further, since the volume of the soil requiring treatment can be reduced and the treatment temperature can be kept low, it is possible to economically recover chemical substances composed of metals such as mercury, gold and platinum from the soil.

[0035]

【Example】

(Example 1) Five points in a certain area (points A to
At point E), 500 g of each soil was sampled, and the soil was classified by the classification device 1 provided in the treatment device shown in FIG. That is, the soil at each point was put into the classifier 1, and the power of the heating wire 4 was turned on while operating the stamp mill of the crushing unit 2. According to the moisture measurement sensor, the initial moisture content was 28%, but after 15 minutes, the reading of the moisture measurement sensor was 3.5%. Then, the pulverization and drying of the soil were confirmed, and the bottom of the pulverization unit 2 was opened and introduced into the classification unit 3. Next, the mixture was classified into the following three fractions by two types of sieves 7a and 7b installed in the classification unit 3. In addition, the vibration was given to the classification part 3 by the vibration generator, and effective classification of the soil was performed. And, fraction A: the particle size of the soil particles was 300 μm or more, fraction B: the particle size of the soil particles was 300 to 75 μm, and fraction C: the particle size of the soil particles was 75 μm or less. Thereafter, measurement was performed for each of fractions A to C, and the following results could be obtained.

[0036]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5] As is clear from Tables 1 to 5, 60 to 90% of chemical substances
Was present in fraction C where the particle size of the soil particles was 75 μm or less. In addition, regarding the mercury, there is a high possibility that the mercury is mixed as ultra-fine particles in the fraction C. In addition, for each fraction, the respective environmental standard values (Notification No. 46 of the Environment Agency on August 23, 1991, Hg: 3 mg or less, Pb: 600 mg or less, Cd: 9 mg or less, As: In addition, TCE: 0.03 mg or less, cis-1,2-dichloroethylene:
0.04 mg or less. For the preparation of 1 L of test solution, 5
0g is required) and the measured value of each chemical substance, the fraction containing the chemical substance exceeding the environmental standard value is point A: fraction B, fraction C point B: fraction C point C : Fraction C Point D: Fraction C Point E: Fraction C

Therefore, the subsequent processing was not performed on the fractions other than the above, and post-processing was performed by the processing apparatus shown in FIG. 1 using only the above fraction. That is, in the area sampled in the present example, the ratio of the fraction A, the fraction B and the fraction C in the soil was 6: 3: 1. From 500 (g / sample) x 5 (sample) = 2500 g, 500 (g / sample) x 3/10 + (500 (g / sample) x 1/10) x 5 =
400 g. Therefore, the amount of soil treatment required for post-treatment could be reduced by 80%.

Here, the conditions of the post-treatment will be described using mercury as an example.

First, the pressure in the container 9 is set to 5 × 10 ^-2 torr
And the temperature in the container 9 was set to 370k. The rotation speed of the rotary unit 10 in the container 9 was 30 rpm. Next, the mercury vapor generated in the container 9 is exhausted by the exhaust device 11, cooled and liquefied by the cooler 13 adjusted to about 10 ° C., introduced into the purifier 14, and the mercury is adsorbed and collected by the activated carbon 15c. did. In addition, a gas flow meter was installed in the exhaust device 11, and the flow rate of mercury vapor was monitored as needed.
As a result of observation by a gas flow meter, after the above fraction was put into the container 9 and 90 minutes later, the flow rate was considered to be 0 L / min, so the mercury vaporization process was terminated. The flow rate of the flow meter is 5200 L
It became. The pressure in the container 9 is 5 × 10 ^-2 torr, the internal temperature is 37
Since it is 0K, the mercury in the above fraction is 2412 mg (1.2 × 10 ^-2 mol), the generated mercury vapor is 5500 L. Therefore,
95% of mercury in the above fraction could be recovered.

The activated carbon was exchanged, and lead and cadmium were recovered under the conditions of the temperature in the vessel 9: 800 and 550 k, and the pressure in the vessel 9: 10 ^-5 and 10 ^-4 torr. Further, trichloroethylene and cis-1,2-dichloroethylene were treated under the above conditions without any particular conditions. As a result, from the above fractionation, lead,
For cadmium, trichlorethylene and cis-1,2-dichloroethylene, respectively, 94%, 95%, 99% and
99% could be recovered.

(Example 2) Heavy metals and organic solvents were recovered from soil in a certain area where mercury contamination was confirmed. First, when the mercury content in the soil was measured, it was about 800p
pm (containing 800 mg of mercury per kg of dry soil) was detected. Mercury was recovered from the soil by the processing apparatus shown in FIG. That is, 5 kg of soil (wet soil) was put into the classification device 1, and the power of the heating wire 4 was turned on while operating the stamp mill of the crushing unit 2. According to the moisture measurement sensor,
Initially, the moisture content was 32%, but after 15 minutes, the reading on the moisture measurement sensor was 3.5%. Therefore, it was confirmed that the soil was crushed and dried, and the bottom of the crushing section 2 was opened to open the classification section 3.
Was introduced. Next, the two types of sieves 7 installed in the classification unit 3
According to a and 7b, it was classified into the following three fractions. The classifying unit 3 is given vibration by a vibration generator,
Effective soil classification has been performed. And Fraction A (2 kg): the particle size of the soil particles is 300 μm or more, Fraction B (1 kg): the particle size of the soil particles is 300 to 75 μm, Fraction C (0.35 kg): the particle size of the soil particles After obtaining three fractions of 75 μm or less, measurement was performed for each of fractions A to C, and the following results could be obtained.

[0042]

[Table 6] Subsequent processing was not performed on the fraction A, and post-processing was performed using the fraction B and the fraction C by the processing apparatus illustrated in FIG. In other words, in the area sampled in this example, the processing amount required for post-processing is from 5 kg.
It was 1.35 kg. Therefore, the amount of soil treatment required for post-treatment could be reduced by 73%.

Here, the conditions of the post-processing will be described using mercury as an example.

First, the pressure in the container 9 is set to 5 × 10 ^-2 torr
And the temperature in the container 9 was set to 370k. The rotation speed of the rotary unit 10 in the container 9 was 30 rpm. Next, the mercury vapor generated in the container 9 is exhausted by the exhaust device 11, cooled and liquefied by the cooler 13 adjusted to about 10 ° C., introduced into the purifier 14, and the mercury is adsorbed and collected by the activated carbon 15c. did. In addition, a gas flow meter was installed in the exhaust device 11, and the flow rate of mercury vapor was monitored as needed.
As a result of observation by a gas flow meter, after the above fraction was put into the container 9 and 90 minutes later, the flow rate was considered to be 0 L / min, so the mercury vaporization process was terminated. Flow meter integrated flow is 1800 L
It became. The pressure in the container 9 is 5 × 10 ^-2 torr, the internal temperature is 37
At 0K, 796 mg (4 × 10 ^-3 mol) of mercury in the above fraction, the amount of mercury vapor generated is 1845 L. Therefore, 98% of mercury in the above fraction could be recovered.

Further, the activated carbon was replaced, and lead was recovered under the conditions of the temperature in the vessel 9: 800 k, the pressure in the vessel 9: 10 ^-5 torr. Further, trichloroethylene and cis-1,2-dichloroethylene were treated under the above conditions without any particular conditions. As a result, 96% and 99% of lead, trichloroethylene and cis-1,2-dichloroethylene
And 100% could be recovered.

(Example 3) When a soil in a certain area was drilled in advance and a sample was analyzed, heavy metals were localized within a range of a radius of 1 m and a height of 3 m. It was found that the heavy metal content was lower than the reference value. The concentration of mercury in the soil in the range is about 50 ppm. A clay layer was formed at a depth of about 2 m from the surface, a silt layer was formed at a depth of about 2 m to 3 m, and a gravel layer was formed at a deeper area.

First, using an excavator, a soil having a radius of 1 m and a depth of 3 m including the localized region of heavy metal in the region is excavated, and the soil (23000 kg: wet soil) is separated by the processing apparatus shown in FIG. It was put into the tank 20. The injected soil is the inclined pipe 1 through which the dry air of about 100 ° C sent from the blower 18 flows.
When it is sucked at 9 (flow rate: 30 L / min), it is introduced so as to diffuse into the separation tank 20 and rises from the lower part to the upper part in the separation tank 20, and then particles such as gravel and sand having a large particle diameter are obtained. The large-diameter particles were collected in the waste duct 21, while the small-diameter particles such as silt and clay were sucked by the suction ducts 22 and 23 and supplied to the vibration tank 25. Since almost no heavy metals were detected from the soil particles collected in the waste duct 21, the soil particles were returned to the excavated area. Next, the soil particles supplied to the vibration tank 25 are given vibration energy by the vibration of the ultrasonic wave having a frequency of 25000 Hz generated from the vibration device 26, and are supplied from the soil particles while traveling from the vibration tank 25 to the sedimentation tank 27. Mercury particulates were separated. The separated mercury has a higher specific gravity than the soil particles, so that the sedimentation when passing through the fluid is fast, and is selectively performed by the adsorbent 28 having an inomidiacetate type chelate resin as a base disposed in the former stage of the sedimentation tank 27. It was able to be recovered by being adsorbed on. When the amount of mercury recovered was calculated from the amount of mercury recovered by the adsorbent 28, about 95% of mercury could be recovered in this example.

(Example 4) The soil in a certain area was drilled in advance and the sample was analyzed. The radius was 1.5 m and the height was 3 m.
It has been found that heavy metals are localized within the range, and that the content of heavy metals in the region larger than the radius is lower than the environmental standard value. The concentration of mercury in the soil in this range is about 120 ppm. A clay layer was formed at a depth of about 2 m from the surface, a silt layer was formed at a depth of about 2 m to 3 m, and a gravel layer was formed at a deeper area.

First, using an excavator, a soil having a radius of 1.5 m and a depth of 3 m including the localized region of heavy metal in the region is excavated, and the soil (50,000 kg: wet soil) is processed by the processing apparatus shown in FIG. It was put into the separation tank 20. The introduced soil is introduced so as to diffuse into the separation tank 20 when sucked into the inclined pipe 19 (flow rate: 30 L / min) through which the dry air of about 100 ° C. sent from the blower 18 flows. After rising upward from the lower part of the sand, large particles such as gravel and sand having a large particle diameter are collected in a waste duct 21, while soil particles such as silt and clay having a small particle diameter are collected in a suction duct 22.
And it was sucked by the suction duct 23 and supplied to the vibration tank 25. Since almost no heavy metals were detected from the soil particles collected in the waste duct 21, the soil particles were returned to the excavated area. Next, the soil particles supplied to the vibration tank 25 are generated by the high frequency generator 30 and have a frequency of 25000.
Hz vibrational energy
The mercury fine particles were separated from the soil particles while traveling from the vibration tank 25 to the sedimentation tank 27. Separated mercury has a higher specific gravity than soil particles, so sedimentation when passing through the fluid is fast,
It was able to be recovered by selectively adsorbing by an adsorbent 28 having an inomidiacetate type chelate resin as a base, which is disposed in the former stage of the settling tank 27. When the amount of mercury recovered was calculated from the amount of mercury recovered by the adsorbent 28, about 96% of mercury could be recovered in this example.

(Example 5) The soil in a certain area was drilled in advance and the sample was analyzed. The radius was 1 m and the height was 3.5 m.
It has been found that heavy metals are localized within the range, and that the content of heavy metals in the region larger than the radius is lower than the environmental standard value. In addition, mercury, lead,
Cadmium concentrations are about 200, 1200 and 20 ppm, respectively. In addition, the formation of a clay layer at a depth of about 2 m from the surface, a silt layer at a depth of about 2 m to 3.5 m, and a formation of gravel in a deeper area were also revealed.

First, an excavator is used to excavate a soil having a radius of 1 m and a depth of 3.5 m including a localized region of heavy metal in the region, and the soil (25,000 kg: wet soil) is processed by the processing apparatus shown in FIG. It was charged into the separation tank 32 from the charging port 31. The soil introduced into the separation tank 32 from the inlet 31 is filtered by the filter 33.
And is sent from the blower 34
Separation tank 32 with 100 ° C dry air (flow rate: 100 L / min)
It flowed from the lower part to the upper part in the inside, and was dissociated to almost soil particles. Gravel, sand with a large particle diameter, and the like were stratified at the lower part of the separation tank 32, and fine particles such as silt and clay migrated and drifted to the upper part of the separation tank 32 by dry air as a fraction 35a. Next, the fraction 35a transferred to the upper part of the separation tank 32
Thus, earth particles such as silt and clay having a small particle diameter flow into the vibration tank 38 via the discharge pipe 37. The particle diameters of gravel and sand with a large particle diameter in the fractions 35b and 35c were almost 300 μm or more, and as a result of the measurement, no heavy metal having a concentration exceeding the environmental standard value was detected. I was able to get it back again. Vibration tank 3 via discharge pipe 37
The soil particles supplied to 8 were given vibration energy by the vibration of an ultrasonic wave having a frequency of 25000 Hz generated from the vibration device 26, and fine particles such as mercury were separated from the soil particles. Subsequently, high-temperature steam was introduced into the vibration tank 38 from the introduction pipe 44, and heavy metals and the like attached to the soil particles were ionized and taken in. Since the separated mercury has a higher specific gravity than the soil particles, the sedimentation when passing through the fluid is fast, and the sedimentation tank 40
Can be recovered by selectively adsorbing with the adsorbent 28 having an inomidiacetate type chelate resin as a base. When the amount of mercury recovered was calculated from the amount of mercury recovered by the adsorbent 28, it was found to be about 92% in this embodiment.
Of mercury could be recovered. On the other hand, heavy metals trapped in the high-temperature steam could be recovered by adsorbing on activated carbon separately disposed in the settling tank 40. The amount of lead and cadmium recovered was calculated from the amount of adsorption recovered by the activated carbon. In this example, approximately 96% and 98% of lead and cadmium could be recovered, respectively.

(Embodiment 6) According to Embodiment 1, the classification device 1
Since it was clear that the soil was classified appropriately, a model experiment on the separation and recovery of mercury was carried out using the apparatus shown in FIG.

That is, as shown in FIG.
30,000 tons of soil (wet soil) containing 30 ppm of mercury is placed in a 30 × 30 m treatment tank 45, and U-shaped sheathed heaters 47 a and 47 b are inserted at equal intervals in four places, and the treatment tank 45 is covered. And heated. Heating the soil is about 400
C. for 8 hours. After heating the soil, the soil was allowed to cool to room temperature, and potassium iodide corresponding to 10 times the amount of mercury in the soil was dissolved in 2 L of water and added to the soil.
Next, as shown in FIG. 5B, a carbon electrode having substantially the same size as the wall surface of the processing tank 45 is placed on the anode 49 and the cathode 5.
0 was installed along the wall so that they faced each other. Then, a current of 3 A / m ² was supplied at a constant voltage of 30 V / m by the DC power supply 48, and electrical treatment was performed for one week. as a result,
The concentration of mercury in the soil in a region 5 cm or more away from the anode 49 was 3 ppm or less, but 5 cm near the anode 49
The concentration of mercury in the soil in the area was 178 ppm.
Therefore, by removing the soil in a region of 5 cm near the anode 49, most of the mercury could be recovered from all the soil.

(Example 7) Mercury was obtained in the same manner as in Example 6, except that a current of 5 A / m ² was supplied at a constant voltage of 30 V / m by a DC power supply 48 and an electric treatment was performed for two weeks. 20
An attempt was made to recover mercury from soil (wet soil) containing 0 ppm. As a result, the concentration of mercury in the soil in the region 5 cm or more from the anode 49 was 3 ppm or less, but the concentration of mercury in the soil in the region 5 cm near the anode 49 was 1200 ppm.
Met. Therefore, by removing the soil in a region of 5 cm near the anode 49, most of the mercury could be recovered from all the soil.

(Embodiment 8) Using the apparatus shown in FIG.
A model experiment similar to that of Example 6 was performed.

That is, as shown in FIG.
30,000 tons of soil (wet soil) containing 30 ppm of mercury is placed in a 30 × 30 m treatment tank 45, and U-shaped sheathed heaters 47 a and 47 b are inserted at equal intervals in four places, and the treatment tank 45 is covered. And heated. The heating of the soil is about 300
C. for 36 hours. After heating the soil, the soil was allowed to cool to room temperature, and potassium iodide corresponding to 15 times the amount of mercury in the soil was dissolved in 2 L of water and added to the soil.
Next, as shown in FIG. 5B, a carbon electrode having substantially the same size as the wall surface of the processing tank 45 is placed on the anode 49 and the cathode 5.
0 along the wall so that the DC power
, A current of 3 A / m ² was passed at a constant voltage of 20 V / m, and electrical treatment was performed for 4 weeks. As a result, from the anode 49
The concentration of mercury in the soil at a distance of 5 cm or more is 3 ppm
The mercury concentration in the soil in the area of 5 cm near the anode 49 was 177 ppm. Therefore,
By removing the soil in the area of 5 cm near the anode 49, most of the mercury could be recovered from all the soil.

Example 9 Mercury was added to a rotary kiln.
Put 10,000 tons of soil (wet soil) containing 0 ppm, and
Heating was performed for hours. After heating the soil, the soil was allowed to cool to room temperature, and the soil was moved to the treatment tank 45.
Then, potassium iodide equivalent to 10 times the amount of mercury in the soil was dissolved in 2 L of water and added to the soil. Next, as shown in FIG.
A current of 3 A / m ^{2 was} applied at a constant voltage of / m, and electrical treatment was performed for one week. As a result, the concentration of mercury in the soil in a region 5 cm or more away from the anode 49 was 3 ppm or less, but the concentration of mercury in the soil in a region 5 cm near the anode 49 was 178 ppm. Therefore, by removing the soil in a region of 5 cm near the anode 49, most of the mercury could be recovered from all the soil.

Example 10 Mercury in Rotary Kiln
Put 10,000t of soil (wet soil) containing 30ppm,
Except for heating for 4 hours, the same as in Example 9,
An attempt was made to recover mercury from soil (wet soil). As a result, the concentration of mercury in the soil in a region 5 cm or more away from the anode 49 was 3 ppm or less, but the concentration of mercury in the soil in a region 5 cm near the anode 49 was 178 ppm. Therefore, by removing the soil in a region of 5 cm near the anode 49, most of the mercury could be recovered from all the soil. (Comparative Example 1) 30 ppm mercury in a rotary kiln
The soil (wet soil) contained was put into 10,000 tons and heated at about 800 ° C for 8 hours. Then, a condenser was connected to the outlet of the rotary kiln to circulate cooling water. As a result, the concentration of mercury in the soil treated by the rotary kiln averaged 5 ppm.

Comparative Example 2 Mercury was added to a rotary kiln.
Put 10,000 tons of soil (wet soil) containing 0 ppm, and
Heating was performed for hours. Then, a condenser was connected to the outlet of the rotary kiln to circulate cooling water. As a result, the concentration of mercury in the soil treated by the rotary kiln averaged 15 ppm.

Here, Examples 6 to 10 and Comparative Example 1
Table 7 shows the operating conditions and results of Comparative Example 2.

[0061]

[Table 7]

[0062]

As described above in detail, according to the treatment apparatus of the first aspect of the present invention, the chemical substance is concentrated by classifying the soil containing the chemical substance based on the size of the soil particles. Since the obtained fraction can be obtained, and the separation and recovery of the chemical substance can be executed from the fraction, it is possible to provide a processing apparatus for easily and reliably recovering the chemical substance from the soil.

Further, by obtaining the fraction in which the chemical substance is concentrated, the volume of the soil to be treated can be reduced, so that it is possible to provide a processing apparatus for economically recovering the chemical substance.

Further, according to the processing apparatus according to the second aspect of the present invention, the soil containing the chemical substance is classified based on the sedimentation velocity of the soil particles to obtain a fraction enriched with the chemical substance. Since the separation and recovery of the chemical substance can be performed from the fractionation, it is possible to provide a processing apparatus that easily and reliably recovers the chemical substance from the soil.

Further, by obtaining a fraction in which the chemical substance is concentrated, the volume of the soil to be treated can be reduced, so that it is possible to provide a processing apparatus for economically recovering the chemical substance.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a processing apparatus according to the present invention.

FIG. 2 is a diagram schematically showing another configuration of the processing apparatus according to the present invention.

FIG. 3 is a diagram schematically showing another configuration of the processing apparatus according to the present invention.

FIG. 4 is a diagram schematically showing another configuration of the processing apparatus according to the present invention.

FIG. 5 is a diagram schematically showing another configuration of the processing apparatus according to the present invention.

[Explanation of symbols]

1 Classifier 2 Classifier 3 Classifier
4 ... heating wire 5 ... moisture measuring sensor 6 ... control devices 7 a, 7
b: sieve 8a to 8c: classification tank 9: container 10: rotary unit 11: exhaust unit 12: adjusting unit 13: cooler 14: purifier 15a to 15c: activated carbon 16: rotation Shaft 17
... Inlet 18 ... Blower 19 ... Incline tube 20 ... Separation tank 21 ... Waste duct 22,23 ... Suction duct 24 ... Conveyer 25 ... Vibration tank 26 ... Vibration device 27 ... Settlement tank 28 ... adsorbent 29 ... remote control device 30 ... high frequency generator 31 ... inlet 32 ...
Separation tank 33 ... Filter 34 ... Blower 35a-35
c ... fractionation 36 ... control valve 37 ... discharge pipe 38 ... vibration tank 39 ... discharge pipe 40 ... sedimentation tank 41 ... recovery pipe 42 ... recovery valve 43 ... recovery tank 44 ... introduction pipe 45 treatment tank 46 power supply 47a, 47b sheath heater 48 DC power supply 49 anode 50 cathode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Chunai 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Yokohama Office (72) Inventor Takeshi Gotanda 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa (72) Inventor Satoshi Kanazawa 8th Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Incorporated Satoru Kanazawa (72) 8-inch Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa (72) Inventor, Naohiko, Nagoya Shinzato, 8-8, Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside of Toshiba Yokohama, Inc. (72) Inventor Hideo Kitamura, 8-8, Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa, Japan (72) Inventor Izumi Komatsu 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Beach business house

Claims (2)

[Claims] 1. A means for classifying soil containing a chemical substance based on the size of soil particles to obtain a fraction enriched with the chemical substance, and a means for separating the chemical substance from the obtained fraction And a means for collecting the separated chemical substance. 2. A means for classifying soil containing a chemical substance based on the sedimentation velocity of soil particles to obtain a fraction enriched with the chemical substance, and a means for separating the chemical substance from the obtained fraction. And a means for collecting the separated chemical substance.