JP2019193919A - Preparation method and device of object to be processed, and processing method and device of particulate matter - Google Patents

Abstract

To provide a processing method of particulate matter which can be performed at a low cost with a simple operation without producing excessive waste.SOLUTION: A processing method of particulate matters includes an agent adding process (step S1-a) of causing an agent to include an aqueous solution which contains divalent iron ions and trivalent iron ions and adding the agent to the particulate matters, a mixing process (step S1-b) of mixing the agent and the particulate matters and a heating process (step S1-c) of heating a mixture of the particulate matters and the agent, and further includes a process (step S1) of preparing/adsorbing a ferromagnetic body consisting essentially of a magnetite onto a surface of the particulate matters and a classification process (step S2) of classifying the particulate matters which prepare and adsorb the ferromagnetic body consisting essentially of the magnetite onto the surface thereof according to magnetic screening.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for treating granular materials such as soil contaminated with radioactive substances.

  Due to the Fukushima Daiichi nuclear power plant accident that originated in the Great East Japan Earthquake, the scattering of radioactive materials (especially radioactive cesium, hereinafter radioactive Cs) to the area around the nuclear power plant caused serious environmental problems. The radioactive Cs released from the nuclear power was deposited on the soil by rainfall, and they took the form of (I) ionic adsorption on the surface of humic substances and soil particles, or (II) trapped inside 2: 1 type clay. In recent years, most of the radioactive Cs in the adsorption form of (I) has been stabilized as form (II), and intermediate storage facilities for contaminated soil (approximately 22 million tons, of which 2/3 is farmland soil) in temporary storage It is considered to be unrealistic to bring everything into the soil, and there is an urgent need to develop a volume reduction technology that can reduce the size of the contaminated soil of form (II).

  Under these circumstances, the development trend of decontamination technology after an accident is roughly divided into three. As the first category, there is an “extraction / adsorption method” system category. Recently, the ratio of the form (II) has increased, and extraction of radioactive Cs has become extremely difficult. Therefore, a technique has been developed in which soil crushing is performed in a subcritical state, and dissolved Cs is extracted and separated. However, the subcritical method has problems such as being unable to earn a sufficient processing amount due to the batch method.

  On the other hand, the technique which removes the radioactive Cs adsorb | sucked to the soil particle | grains with the soil fine particle precedes. Among them, the “microbubble flotation / classification method” is a representative example (second category). Recently, as a more advanced suspension water treatment technique, a technique for separating soil fine particles from wastewater by a superconducting magnetic separation method has also been proposed. These are unsuitable for large-scale wastewater treatment essential downstream of the process and treatment of farmland soil containing a lot of root hairs, and the latter has problems in cost and throughput.

The third category includes dry processing such as “heat separation” or “heat volume reduction” processing. For example, there is a method of adding _1/2 to an equivalent amount of CaCl ₂ to contaminated soil containing biotite as a main component and heating it at a temperature of less than 800 ° C. for 2 hours to separate it as Cs chloride. This method also has technical problems such as a large amount of waste.

  Unlike the above decontamination technique, there is a method of classifying and decontaminating dry soil at no waste water and at room temperature (see, for example, Patent Documents 1 and 2). In this method, contaminated soil and ferromagnetic powder are mixed and magnetically selected to classify the contaminated soil. The soil contaminated with radioactive Cs can be decontaminated by removing the contaminated soil having a small particle size because the smaller the particle size, the higher the concentration of radioactive Cs.

Japanese Unexamined Patent Publication No. 2017-39123 JP 2017-1113744 A

  The method described in Patent Document 1 or Patent Document 2 is considered to be a simple and excellent method without generating extra waste including waste water and the like. However, since this method is dry, it generates dust. It is easy to take measures. Moreover, since the contaminated soil contains wood chips, root hairs, etc., these treatments are also required.

  An object of the present invention is to provide a powder processing method and apparatus that can be implemented at low cost with a simple operation without generating extra waste, and a method for preparing an object that can be used in the powder processing method. And providing an apparatus.

  The present invention is a method for preparing an object to be processed so as to be magnetically selectable, wherein the object to be processed is a granular material, and an agent contains an aqueous solution containing divalent iron ions and trivalent iron ions. Including a mixing step of mixing the powder and the drug, and generating and adsorbing a ferromagnetic material mainly composed of magnetite on the surface of the powder and granular material. It is.

  The preparation method of the to-be-processed object of this invention is characterized by including a pH adjuster in the said chemical | medical agent.

  Moreover, the preparation method of the to-be-processed object of this invention is characterized by including the water | moisture-content evaporation process of evaporating a water | moisture content other than the said mixing process.

  Moreover, the preparation method of the to-be-processed object of this invention includes the heating process which heats the mixture of the said granular material and the said chemical | medical agent in parallel with the said mixing process, or in addition to the said mixing process, the said granular material, It includes a heating step of heating the mixture with the drug.

  Moreover, the preparation method of the to-be-processed object of this invention is characterized by the temperature of the said heating process being 350 degrees C or less, Preferably it is 300 degrees C or less, More preferably, it is 250 degrees C or less.

  Further, in the preparation method of the object to be processed according to the present invention, the granular material contains an organic substance, and the organic substance is carbonized in the heating step, and a ferromagnetic body mainly composed of magnetite is generated and adsorbed on the surface of the carbide. It is characterized by that.

Moreover, the preparation method of the to-be-processed object of this invention is the particle diameter of the ferromagnetic material which has as a main component the magnetite to produce | generate and adsorb | suck to the surface of the said granular material by controlling one or more of following (A) groups It is characterized by controlling cohesiveness.
(A) pH of drug, ratio of trivalent iron ion to divalent iron ion, divalent iron ion concentration, trivalent iron ion concentration, reaction time, reaction temperature, reaction field atmosphere (oxidation / reduction ), Types of anions in aqueous solution

  Moreover, this invention is a processing method of the granular material characterized by including the classification process which classifies the to-be-processed object obtained by the preparation method of the said to-be-processed object by magnetic selection.

  In the method for processing a granular material according to the present invention, the granular material is soil.

  The present invention includes a reaction device that mixes a drug and a granular material that is an object to be processed, and generates and adsorbs a ferromagnetic material mainly composed of magnetite on the surface of the powder particle; and the reaction device includes the drug And a chemical supply apparatus for supplying a treatment, wherein the chemical includes an aqueous solution containing divalent iron ions and trivalent iron ions.

  The apparatus for preparing an object to be processed according to the present invention further includes a heating unit for heating the mixture of the granular material and the drug and / or an evaporation unit for evaporating water from the mixture of the granular material and the drug. It is characterized by.

  The present invention includes a processing apparatus for a granular material, comprising: a preparation apparatus for the object to be processed; and a magnetic separator for magnetically sorting the object to be processed obtained through the preparation apparatus for the object to be processed. is there.

  The granular material processing apparatus of the present invention is characterized in that the granular material is soil.

  ADVANTAGE OF THE INVENTION According to this invention, the processing method and apparatus of the granular material which can be implemented at low cost by simple operation, without generating extra waste, The preparation method of the to-be-processed object which can be used with the processing method of the granular material And an apparatus can be provided.

It is a flowchart explaining the processing method of the granular material of 1st Embodiment of this invention. It is a block diagram of the processing apparatus 1 of the granular material of this invention. It is a schematic diagram which shows the point of the magnetic force selection implemented in the Example of this invention.

  FIG. 1 is a flowchart for explaining a method of processing a granular material according to the first embodiment of the present invention. The processing method of the granular material of this invention can be divided roughly into two processes, a front | former stage and a back | latter stage. The first stage is a step (step S1) of preparing a granular material (powdered granular material) that is an object to be processed so as to be magnetically separable, and the second stage is a magnetic field sorting of the granular material that has been prepared to be magnetically separable in the previous stage. This is a magnetic force sorting step (step S2) for sorting into magnetized and non-magnetized products.

Specifically, the process of preparing the powder particles so that they can be magnetically generated produces a ferromagnetic material mainly composed of magnetite (main component: Fe ₃ O ₄ = Fe ₂ O ₃ · FeO) on the surface of the powder particles. A step of adsorbing (hereinafter referred to as a ferromagnetic material generation adsorption step), a drug addition step (step S1-a) for adding a drug to the granular material, and a mixing step for stirring and mixing the drug and the granular material (Step S1-b) and a heating step (step S1-c) for heating the mixture of the drug and the granular material.

  In this treatment method, there are no particular limitations on the granular material that is the object to be treated, and as the granular material, soil, incinerated ash, sludge, a mixture thereof, and those in which contaminants adhere, adsorb, or adhere to them. Is mentioned. Examples of the pollutants include residual organic pollutants (POPs) such as heavy metals, dioxins, PCBs and agricultural chemicals, radioactive substances, and the like. The radioactive substance is not limited to a specific substance, and a wide range of radioactive substances such as cesium Cs, plutonium Pu, uranium U, and radium Ra can be targeted.

  In the contaminated soil in which the contaminant is mainly fixed, adsorbed or adhered to the soil surface, the smaller the particle size, the higher the concentration of the contaminant. This is because soil with a smaller particle size has a larger specific surface area. Since this treatment method can classify contaminated soil by magnetic sorting as described later, it is possible to separate and decontaminate highly contaminated soil.

  Although the particle size of a granular material is not specifically limited, This processing method can be used conveniently for the processing of the granular material with which sieving is difficult. The moisture content of the granular material is not particularly limited. Even in an absolutely dry state, even a granular material containing moisture can be processed as it is. Even if there is a lot of moisture, it is heated in the heating process and the moisture evaporates. However, the more moisture there is, the more energy required to evaporate it, so it is better that the moisture contained in the granular material is less. If dehydration operation is possible with respect to a granular material, it is preferable to perform dehydration operation previously and to reduce a moisture content.

  In some cases, the granular material includes a lump. The granular material containing such a lump can also be processed by this processing method, and can be mixed with a chemical | medical agent, crushing a lump in a mixing process. Moreover, since the processing method of the granular material of this embodiment is equipped with a heating process, you may crush a lump with this heating process.

  Some of the granular materials contain organic substances such as plants, leaves, wood chips, and root hairs, but such granular materials can also be treated by the present treatment method. Since the processing method of the granular material of this embodiment is equipped with a heating process, organic substance turns into a carbide | carbonized_material by this heating process.

As the drug, an alkaline aqueous solution containing divalent iron ions Fe ²⁺ and trivalent iron ions Fe ³⁺ is used. This medicine is prepared by preparing an aqueous solution containing divalent iron ions Fe ²⁺ , an aqueous solution containing trivalent iron ions Fe ³⁺ , and an alkaline solution, and mixing them immediately before supplying them to the powder particles. Is good.

The anion of the aqueous solution containing the divalent iron ion Fe ²⁺ and the anion of the aqueous solution containing the trivalent iron ion Fe ³⁺ are not particularly limited. ^Examples of the aqueous solution containing divalent iron ion Fe ²⁺ include iron dichloride (ferrous chloride), and examples of the aqueous solution containing trivalent iron ion Fe ³⁺ include iron trichloride (ferric chloride). The concentration of the divalent iron ion Fe ²⁺ in the aqueous solution and the concentration of the trivalent iron ion Fe ^{3+ in} the aqueous solution are not particularly limited.

The alkaline solution is not particularly limited. Examples of the alkaline solution include sodium hydroxide NaOH and calcium hydroxide Ca (OH) ₂ .

The ratio of the divalent iron ion Fe ²⁺ and the trivalent iron ion Fe ³⁺ in the drug is basically 1: 1, but the divalent iron ion Fe ²⁺ is unstable and the trivalent iron ion Fe Since it is easy to change to ³⁺ , it is preferable to keep the divalent iron ion Fe ²⁺ higher than the trivalent iron ion Fe ³⁺ .

  The pH of the drug is preferably 9-12, more preferably pH≈11.

  About 1-5 mL may be sufficient as the addition amount of the chemical | medical agent with respect to a granular material with respect to 10 g of contaminated soil.

  In the drug addition step (step S1-a), the method for adding the drug to the granular material is not particularly limited, but a post-process mixing step (step S1-b) of the drug and the granular material can be considered. For example, it is preferable to add it as uniformly as possible to the granular material by spraying the medicine.

  The mixing step (step S1-b) is not particularly limited as long as the drug and the granular material can be sufficiently stirred and mixed, and the stirring device and the stirring procedure are not particularly limited. The mixing step may be carried out independently after the drug addition step, but it is efficient and practical to integrate with the drug addition step and to stir and mix while adding the drug. If the mixing step and the chemical supply step are integrated, dust is hardly generated. In the case where the object to be treated is soil contaminated with radioactive substances, dust generation prevention measures are important. From this point of view, it is preferable to integrate the mixing step and the chemical supply step.

  The mixing time in the mixing step is not particularly limited. When a heating step is provided later as in the present embodiment, a short time may be required, and the mixing operation may be performed at normal temperature (atmospheric temperature) and atmospheric pressure.

  A heating process (step S1-c) heats the mixture of the chemical | medical agent and powder which are obtained through a mixing process. The heating temperature is preferably 350 ° C. or lower, preferably 300 ° C. or lower, more preferably 250 ° C. or lower. If the heating temperature exceeds 350 ° C., there is a concern about the resynthesis of dioxins. If the heating temperature is 350 ° C. or lower, there is no concern about magnetism loss of magnetite (Curie point: 858K).

  The heating operation in the heating step is not particularly limited, but it is preferable to use a stirring and mixing operation in combination from the viewpoint of uniform temperature, removal of moisture, and prevention of aggregation of the granular material. The heating time is determined from the time (reaction time) necessary for generating and adsorbing a ferromagnetic material mainly composed of magnetite on the surface of the granular material. Since the production rate of the ferromagnetic material mainly composed of magnetite differs depending on the heating temperature (reaction temperature), the heating time may be appropriately determined according to the reaction temperature.

  The heating step also serves as a drying step for drying the granular material on which the ferromagnetic material mainly composed of magnetite is generated and adsorbed. Powders and chemicals used in the ferromagnetic material generation and adsorption process contain moisture, so that a powder containing a ferromagnetic material mainly composed of magnetite is generated and adsorbed unless it is completely dried in the ferromagnetic material generation and adsorption process. In the granule, particles aggregate due to the influence of moisture. Since the granular material obtained through the ferromagnetic material generation and adsorption process is magnetically selected in the subsequent process, the moisture is evaporated in the heating process prior to this, and the powder in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed Disperse the granules sufficiently.

  The heating temperature and heating time in the heating process are basically determined based on the generation / adsorption of a ferromagnetic material mainly composed of magnetite. However, when the granular material contains an organic substance, the organic substance is carbonized, and this It is preferable to determine the heating temperature and the heating time so that a ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface of the carbide.

  The particle size and dispersibility of the ferromagnetic material mainly composed of magnetite that is generated and adsorbed on the surface of the granular material is not only the temperature and time in the heating process, but also the reaction field atmosphere, specifically the reaction field is oxidizing. Since it is influenced by the atmosphere or the reducing atmosphere, it is preferable to determine the reaction field so that the ferromagnetic material mainly composed of magnetite has a small particle size and excellent dispersibility.

  The mechanism by which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface of the granular material in the ferromagnetic material generation and adsorption process having the above-described configuration is considered as follows. Hereinafter, a granular material is demonstrated as soil.

When a chemical | medical agent is added to soil, ion exchange with the monovalent ^| monohydric ion species in soil and the bivalent iron ion Fe2 ⁺ or the trivalent iron ion Fe3 ⁺ will be performed. Next, a chemical reaction occurs on the soil surface, and a ferromagnetic material mainly composed of magnetite is generated on the soil surface, and the ferromagnetic material is adsorbed on the soil surface.

It is known that the cation exchange capacity (CEO) between the 2: 1 type clay mineral and the 1: 1 type clay mineral is about 80 times larger at the former. For this reason, the divalent iron ion Fe ²⁺ and the trivalent iron ion Fe ³⁺ are preferentially adsorbed by the 2: 1 type clay mineral, and the ferromagnetic material mainly composed of magnetite is also the surface of the 2: 1 type clay mineral. Is preferentially generated and adsorbed.

  As described in the Background Art section, radioactive Cs released by the nuclear accident is deposited in the soil by rainfall, and is finally captured inside the 2: 1 type clay. From this, it can be seen that the ferromagnetic material generation adsorption step shown in the present embodiment, and further, the treatment method of the granular material shown in the present embodiment can be suitably used for the treatment of soil contaminated with radioactive Cs.

  In the present processing method of granular material, since the granular material obtained through the ferromagnetic material generation adsorption step is subjected to magnetic selection in the next step, the magnetic selection material suitable for magnetic selection in the ferromagnetic material generation adsorption step. Is preferred, and a method that can efficiently generate it is preferred. In this respect, a ferromagnetic material containing magnetite as a main component can be said to be a preferable magnetic material, and a ferromagnetic material generation and adsorption step is also simple and a preferable method.

  A ferromagnetic material mainly composed of magnetite that is generated and adsorbed on the surface of the granular material from the viewpoint of magnetic selection preferably has a small particle size and is uniformly dispersed on the surface. Moreover, the thing with little usage-amount of the chemical | medical agent used for producing | generating and adsorbing the ferromagnetic material which has magnetite as a main component is preferable.

The ferromagnetic material mainly composed of magnetite that is generated and adsorbed on the surface of the granular material can control the particle size and / or cohesiveness by controlling any one of the groups (A) below. The following control items (parameters) may be appropriately selected depending on the properties of the granular material.
(A) pH of drug, ratio of trivalent iron ion to divalent iron ion, divalent iron ion concentration, trivalent iron ion concentration, reaction time, reaction temperature, reaction field atmosphere (oxidation / reduction ), Types of anions in aqueous solution

  In the magnetic force sorting step (step S2), the powder particles in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface obtained through the previous step (step S1) are magnetically sorted. The magnetic separator and magnetic separation method used in the magnetic separation process are not particularly limited, and known magnetic separators and magnetic separation methods can be used. Depending on the magnetic separator and magnetic separation method, it may be impossible to process a high-temperature magnetic selection material. In such a case, a cooling step for cooling the granular material is provided between the ferromagnetic material generation adsorption step and the magnetic force selection step.

  The outline of the processing mechanism of the present processing method having the above configuration is as follows. In the ferromagnetic material production and adsorption process, the amount of magnetite-based ferromagnetic material produced and adsorbed on the granular material (per unit mass of contaminated soil) is larger for smaller granular materials due to the specific surface area. Become. In the magnetic force sorting step, the granular material having a small particle size has a small weight and becomes a magnetized product because of the large amount of adsorption of the ferromagnetic material mainly composed of magnetite. On the other hand, a granular material having a large particle size has a large weight and becomes a non-magnetized substance because the adsorption amount of a ferromagnetic material mainly composed of magnetite is small.

  As described above, in the process of generating and adsorbing a ferromagnetic material on a granular material, a ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface, and the granular material can be classified by magnetically selecting it. it can. As radioactive material-contaminated soil has a smaller particle size, the concentration of the contaminant is higher. Therefore, the radioactive material-contaminated soil can be concentrated and decontaminated by treating the radioactive material-contaminated soil using this treatment method. .

  In the present processing method, the organic matter contained in the granular material becomes a carbide in the heating step (step S1-c), so that the volume of the object to be processed is reduced. In addition, a ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface of the carbide during the ferromagnetic material generation and adsorption process. Since carbide has a lower density than contaminated soil, it becomes a magnetic deposit in the magnetic separation process.

  The processing method of the granular material of this invention can be variously changed based on the processing method of the granular material of 1st Embodiment. Hereinafter, the modification of the granular material of 1st Embodiment is demonstrated.

  In the processing method of the granular material of the first embodiment, the granular material is used as it is as an object to be processed. However, prior to this processing method, the granular material is classified using a sieve or the like, May be removed. It is known that radioactive material-contaminated soil has a higher concentration of radioactive material as the particle size is smaller, and conversely, the concentration of radioactive material in coarse particles is relatively lower (for example, the table of JP2013-242210A). 1). Therefore, if the coarse particles are removed in advance and the remaining contaminated soil is magnetically sorted, the radioactive material contaminants can be efficiently concentrated and decontaminated.

In the processing method of the granular material of 1st Embodiment, although a heating process (step S1-c) is provided in the process (step S1) which prepares a granular material so that magnetic force selection is possible, you may abbreviate | omit a heating process. A ferromagnetic material mainly composed of magnetite that is generated and adsorbed on the surface of the granular material is generated by a reaction between divalent iron ions Fe ²⁺ and trivalent iron ions Fe ³⁺ contained in the drug. This reaction proceeds more rapidly at higher temperatures but also at room temperature.

  When the heating step is omitted in the step of preparing the powder particles so as to be magnetically selectable (step S1), a step of elongating the stirring step and further evaporating moisture is required. For the step of evaporating moisture, vacuum drying or the like may be used.

  If the heating step is omitted in the step of preparing the particles so as to be magnetically selectable (step S1), the processing speed is reduced, but the heating device is not required and the energy consumption is reduced. Furthermore, there is a merit that the operation and the apparatus for cooling the granular material are unnecessary between the step of preparing to be magnetically selectable (step S1) and the magnetic force selecting step (step S2).

In the method for treating a granular material according to the first embodiment, an alkaline aqueous solution containing divalent iron ions Fe ²⁺ and trivalent iron ions Fe ³⁺ is used as a chemical, but an aqueous solution containing divalent iron ions Fe ²⁺ is used. An aqueous solution containing trivalent iron ions Fe ³⁺ and an alkaline solution may be prepared separately, and each drug may be added separately in the drug addition step (step S1-a). Or may be changed timing of an aqueous solution with an alkali solution containing iron ions Fe ³⁺ in solution and trivalent containing divalent iron ions Fe ^2+.

  Next, the processing apparatus 1 of the granular material of this invention is demonstrated. FIG. 2 is a configuration diagram of the powder particle processing apparatus 1 according to the present invention. Hereinafter, assuming that the granular material is radioactive material contaminated soil (hereinafter referred to as contaminated soil), the configuration of the granular material processing apparatus will be described.

  The processing apparatus 1 of the granular material of this invention is a continuous processing apparatus which processes contaminated soil continuously, the mixing apparatus 11 which stirs and mixes contaminated soil and a chemical | medical agent, and the chemical | medical agent supply apparatus which supplies a chemical | medical agent to the mixing apparatus 11 21, a contaminated soil supply device 26 that supplies contaminated soil to the mixing device 11, a reaction device 31 that generates and adsorbs a ferromagnetic material mainly composed of magnetite on the surface of the contaminated soil, and a cooling device that cools the contaminated soil after the reaction 41. A magnetic separator 51 that magnetically sorts contaminated soil after cooling is included.

  The mixing device 11 is a known mixing device including a horizontal biaxial stirring blade 13 in the tank 12 and has a stirring function and a transport function. The mixing device 11 stirs and mixes the chemical and the contaminated soil continuously supplied from the chemical supply device 21 and the contaminated soil supply device 26 under atmospheric pressure and atmospheric temperature, and continuously mixes the contaminated soil and the chemical mixture. Discharge.

  The mixing device 11 is not particularly limited as long as it can stir and mix contaminated soil and chemicals in a closed space. What is necessary is just to use the thing suitable for the property of contaminated soil, such as the particle size of a contaminated soil, a moisture content, and the presence or absence of a lump. When the moisture content of the contaminated soil is high, the mixing operation of the contaminated soil and the drug can be said to be a kneading operation. In such a case, an apparatus suitable for kneading may be used. Moreover, in the mixing apparatus 11, you may provide the spray nozzle for spraying a chemical | medical agent in the tank 12 in order to improve mixing performance.

The drug supply device 21 is a device that supplies a fixed amount of drug to the mixing device 11, and includes a drug supply tank 22 including a stirrer 23 and a fixed amount supply pump 24. The chemical supply tank 22 is filled with an alkaline aqueous solution containing divalent iron ions Fe ²⁺ and trivalent iron ions Fe ³⁺ .

  The contaminated soil supply device 26 is a device that quantitatively supplies contaminated soil to the mixing device 11, and is a screw feeder 28 with a hopper 27. As a powder and powder quantitative supply device, a table feeder and the like are known in addition to a screw feeder. However, the type of the device is not particularly limited as long as the contaminated soil can be quantitatively supplied.

  The reaction device 31 is a device that heats a mixture of contaminated soil and a chemical, reacts the chemical, and generates and adsorbs a ferromagnetic material mainly composed of magnetite on the surface of the contaminated soil. The reaction device 31 is an indirect heating type rotary kiln that includes an inner cylinder 32 that rotates in connection with a driving device (not shown) and an outer cylinder 37 that is fixed so as to cover the inner cylinder 32.

  The inner cylinder 32 includes an inlet 33 for receiving a mixture of contaminated soil and medicine discharged from the mixing device 11 at one end, and an outlet hood 34 for discharging the heated mixture at the other end. The inner cylinder 32 has a slightly higher inlet portion 33 than the outlet hood 34 side, and is slightly inclined from the inlet portion 33 toward the outlet hood 34 side.

  The inlet 33 and the outlet hood 34 are connected to the inner cylinder 32 so as to prevent leakage of gas generated in the inner cylinder 32. An exhaust port 35 for discharging a gas such as water vapor generated when the mixture is heated is provided at the upper part of the outlet hood 34, and an exhaust port 36 for discharging the heated mixture is provided at the lower part of the outlet hood 34. ing.

  The outer cylinder 37 includes a heating gas supply port and a discharge port, receives the heating gas sent from a heating gas supply device (not shown), and heats the mixture in the inner cylinder 32 using this as a heating medium. A heating gas supply port is provided on the outlet hood 34 side, and a heating gas discharge port is provided on the inlet portion 33 side.

  The mixture of the contaminated soil and the chemical discharged from the reactor 31 is heated to a predetermined temperature and a predetermined temperature in the process of moving from the inlet portion 33 of the inner cylinder 32 to the discharge port 36, and magnetite is mainly used on the surface of the contaminated soil. Generates and adsorbs ferromagnetic materials as components. The contaminated soil in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface is discharged from the discharge port 36. On the other hand, a gas such as water vapor generated by the heating operation of the mixture of contaminated soil and chemicals is led from the exhaust port 35 to an exhaust gas processing device (not shown).

  The reactor 31 only needs to be able to heat a mixture of contaminated soil and chemicals to a predetermined time and a predetermined temperature to generate and adsorb a ferromagnetic material mainly composed of magnetite on the surface of the contaminated soil. It is not particularly limited. The reactor 31 having excellent stirring and mixing properties is preferable from the viewpoint of reactivity and thermal efficiency because it generally has excellent heat transfer properties. On the other hand, since the reaction device 31 having excellent stirring and mixing properties easily generates dust, this countermeasure is necessary.

  The cooling device 41 cools the contaminated soil in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface discharged from the reaction device 31 to a temperature at which it can be supplied to the subsequent magnetic separator 51. The cooling device 41 is a horizontal uniaxial stirring device with a jacket, and includes a horizontal uniaxial screw 43 in a stirring tank 42, and a jacket 44 is attached so as to cover the stirring tank 42. The cooling medium supplied to the jacket 44 is water.

  A rotary feeder 46 is provided at the outlet of the agitation tank 42 as a device for supplying a fixed amount of cooled contaminated soil to the subsequent magnetic separator 51.

  The cooling device 41 may be of a type that can cool the contaminated soil in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface discharged from the reaction device 31 to a temperature that can be supplied to the subsequent magnetic force sorting device 51. Etc. are not particularly limited. The fixed amount supply device that supplies the cooled contaminated soil in a fixed amount to the magnetic separator 51 is not limited to the rotary feeder 46.

  The magnetic separator 51 magnetically sorts contaminated soil that is supplied in a fixed amount via the rotary feeder 46. The magnetic separator 51 shown here is a known conveyor-type magnetic separator, and classifies contaminated soil into magnetic and non-magnetic substances. Here, without being limited to the specific magnetic separator 51, various magnetic separators such as a drum type magnetic machine and a magnetic machine capable of separating contaminated soil into three or more can be used.

  Next, the procedure for processing contaminated soil by the powder processing apparatus 1 shown in FIG. 2 will be described.

  The contaminated soil is supplied to the mixing device 11 via the contaminated soil supply device 26, and the drug is supplied to the mixing device 11 via the drug supply device 21. Here, the contaminated soil and the drug are sufficiently mixed with stirring. The mixture is discharged from the discharge port and sent to the inner cylinder 32 via the inlet 33 of the reaction device 31.

  The mixture is heated while moving the inner cylinder 32 from the inlet 33 toward the outlet 36. In this process, the drug reacts and a ferromagnetic material composed mainly of magnetite is generated and adsorbed on the surface of the contaminated soil. When the contaminated soil contains plants such as root hairs, they become carbide in the reactor 31 and a ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface in the same manner as the contaminated soil. The contaminated soil on which the ferromagnetic material mainly composed of magnetite is generated and adsorbed is sent to the cooling device 41 connected to the discharge port 36. A gas such as water vapor generated in the course of heating the mixture is led from the exhaust port 35 to an exhaust gas processing device (not shown).

  The contaminated soil in which the ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface discharged from the reaction device 31 is cooled to a temperature that can be supplied to the magnetic force sorting device 51 by the cooling device 41, and then the rotary feeder 46 is used. The magnetic flux is supplied to the magnetic separator 51 through a fixed amount, and is separated into a magnetized product and a non-magnetized product.

  A ferromagnetic material mainly composed of magnetite has a larger amount of generation / adsorption (per unit mass of contaminated soil) as the contaminated soil has a smaller particle size because of the specific surface area. In addition, contaminated soil with a small particle size has a small weight and becomes a magnetized material because of a large amount of adsorption of a ferromagnetic material mainly composed of magnetite. On the other hand, contaminated soil with a large particle size has a high weight and is non-magnetized due to a small amount of adsorption of a ferromagnetic material mainly composed of magnetite.

  As described above, by using the powder processing apparatus 1, the contaminated soil is sorted by the particle size, that is, classification is possible. Radioactive material-contaminated soil can be decontaminated by using the present treatment apparatus 1 because soil with a smaller particle size has higher radioactive material.

  The processing apparatus of the granular material of this invention is not limited to the processing apparatus shown in FIG. In the granular material processing apparatus 1 shown in FIG. 2, the mixing apparatus 11 and the reaction apparatus 31 are separated, but the mixing apparatus and the reaction apparatus may be integrated. Such a processing apparatus can be suitably applied when the reaction temperature is set low.

  Even when the reaction temperature is relatively high, only the reaction apparatus may be used, and the mixing apparatus may be omitted by using the former stage as the mixing zone and the latter stage as the reaction zone. When the indirectly heated rotary kiln shown in FIG. 2 is used in such a reaction apparatus, the outer cylinder 37 may be provided only from the center to the discharge port side.

  The powder processing apparatus 1 shown in FIG. 2 includes a cooling device 41 and cools the contaminated soil discharged from the reaction device 31, but the temperature of the contaminated soil discharged from the reaction device 31 is If the specification is satisfied, the cooling device 41 is unnecessary. In such a case, a quantitative supply device such as a rotary feeder may be installed at the discharge port 36 of the reaction device 31.

  When controlling the particle size and / or cohesiveness of a ferromagnetic material mainly composed of magnetite that is generated and adsorbed on the surface of contaminated soil by controlling the atmosphere in the reaction field, gas is supplied into the reactor. An atmosphere gas supply pipe is provided for supplying air, nitrogen gas, combustion exhaust gas, carbon dioxide gas, or a mixture of these gases.

  The processing apparatus of the granular material of this invention is not limited to a continuous processing apparatus, A semi-batch type and a batch type processing apparatus may be sufficient.

  As shown in the above-described embodiment, by using the method and apparatus for treating granular material of the present invention, it is possible to treat contaminated soil and the like with a simple operation without generating extra waste. Moreover, the preparation method and apparatus of the to-be-processed object of this invention can be used suitably as a pre-processing and pre-processing apparatus of the processing method and processing apparatus of the granular material of this invention.

  Moreover, the preparation method of the to-be-processed object of this invention and the processing method of a granular material add a liquid chemical | medical agent to granular materials, such as contaminated soil, and make this react and make magnetite the main component on the surface of a granular material. Since the ferromagnetic material is generated and adsorbed, the ferromagnetic material is easily generated and adsorbed uniformly, and the generation of dust is further suppressed. In addition, it can be said that it is a practical method and apparatus such that it can be treated as it is even if wood chips, root hairs, etc. are contained in the contaminated soil.

  In addition, the method for preparing an object to be processed and the method for treating a granular material according to the present invention control the particle size and / or cohesiveness of a ferromagnetic material mainly composed of magnetite to be generated and adsorbed on the surface of the granular material. Therefore, it is possible to efficiently process the granular material with a small amount of drug. Furthermore, the present treatment method can be used for various kinds of powders and a wide range of applications.

  While the preferred embodiment has been described with reference to the drawings, those skilled in the art will readily appreciate various changes and modifications within the scope of this specification after reviewing this specification. Therefore, such changes and modifications are interpreted as being within the scope of the invention defined by the claims.

Examples 1-3
Add 10mL of 10ppm iron dichloride aqueous solution, 1ppm 10ppm iron trichloride aqueous solution 1mL and sodium hydroxide aqueous solution 1mL to 10g of pure sand and mix them with stirring, then air atmosphere (air atmosphere) at room temperature for 2-3 days The sample was dried naturally to obtain a sample for sorting. Examples 1-3 differ in pH.

Examples 4-6
Similarly, 1 mL of a 10 ppm iron dichloride aqueous solution, 1 mL of 10 ppm iron trichloride aqueous solution and 1 mL of sodium hydroxide aqueous solution are added to 10 g of pure sand, and these are stirred and mixed. Then, using an electric furnace, the atmosphere (air Atmosphere) and heated at 250 ° C. for 2 hours to obtain a sample for an object to be selected. Examples 4-6 differ in pH.

Magnetic Adhesion Sorting Test After setting each sample to a moisture content of 1% or less, put the sample in a special mixing bottle 101 shown in FIG. 3, insert an iron core 102 at the top of the mixing bottle 101, and attach a neodymium magnet 103. (See FIG. 3A), the mixing bottle 101 was shaken by hand for about 30 seconds (see FIG. 3B). Thereafter, the plastic cover 104 at the upper part of the bottle was removed, the neodymium magnet 103 and the iron core 102 were pulled out on the tray, and the magnetic deposits were collected (see FIG. 3C). Thereafter, the plastic cover 104, the neodymium magnet 103, and the iron core 102 were attached, and the residue (non-magnetized material) was magnetically selected in the same manner as before. This magnetic separation operation was performed five times for each sample.

Comparative Example 1
Only 10 g of pure sand soil was put into a dedicated mixing bottle 101 shown in FIG. 3, and a magnetic adhesion sorting test was performed in the same manner as the sample.

Results of Magnetic Adhesion Sorting Test The magnetic adhesion ratio was calculated from the formula (1), and the magnetic adhesion magnification of each sample when the magnetic adhesion ratio of only pure sand soil (Comparative Example 1) is 1 is shown in Table 1.

  As shown in Table 1, all of the samples of Examples 1 to 6 had an increased magnetic adhesion rate as compared with Comparative Example 1. Regarding the relationship between the presence / absence of heating at the time of sample preparation and the magnetic adhesion rate, the magnetic adhesion rate increased 1.6 to 2.1 times by performing the heating operation as compared with the case of non-heating. Further, regarding the relationship between the pH and the magnetic adhesion rate at the time of sample preparation, a peak of the magnetic adhesion rate appeared at pH≈11.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 11 of granular material 21 Mixing apparatus 21 Drug supply apparatus 26 Contaminated soil supply apparatus 31 Reactor 41 Cooling apparatus 46 Rotary feeder 51 Magnetic separator

Claims (13)

A method of preparing a workpiece to be magnetically selectable,
The object to be treated is a granular material,
The drug comprises an aqueous solution containing divalent iron ions and trivalent iron ions,
A method for preparing an object to be processed, comprising a mixing step of mixing the powder and the drug, and generating and adsorbing a ferromagnetic material mainly composed of magnetite on the surface of the powder and particle.   The method for preparing an object to be treated according to claim 1, wherein the drug contains a pH adjuster.   The method for preparing an object to be processed according to claim 1 or 2, further comprising a water evaporation step of evaporating water in addition to the mixing step. Including a heating step of heating the mixture of the powder and the drug in parallel with the mixing step,
Alternatively, the method for preparing an object to be processed according to any one of claims 1 to 3, further comprising a heating step of heating the mixture of the powder and the drug in addition to the mixing step.   The method for preparing an object to be processed according to claim 4, wherein the temperature in the heating step is 350 ° C or lower, preferably 300 ° C or lower, more preferably 250 ° C or lower. The granular material contains organic matter,
The method for preparing an object to be processed according to claim 4 or 5, wherein the organic matter is carbonized in the heating step, and a ferromagnetic material mainly composed of magnetite is generated and adsorbed on the surface of the carbide. . By controlling one or more of the following group (A), the particle size and / or cohesion of a ferromagnetic material mainly composed of magnetite to be generated and adsorbed on the surface of the granular material is controlled. The preparation method of the to-be-processed object of any one of Claim 1 to 6.
(A) pH of drug, ratio of trivalent iron ion to divalent iron ion, divalent iron ion concentration, trivalent iron ion concentration, reaction time, reaction temperature, reaction field atmosphere (oxidation / reduction ), Types of anions in aqueous solution   A method for treating a granular material, comprising a classification step of classifying a workpiece obtained by the method for preparing a workpiece according to any one of claims 1 to 7 by magnetic separation.   The said granular material is soil, The processing method of the granular material of Claim 8 characterized by the above-mentioned. A reaction apparatus for mixing a drug and a granular material to be treated, and generating and adsorbing a ferromagnetic material mainly composed of magnetite on the surface of the granular material;
A drug supply device for supplying the drug to the reaction device;
With
An apparatus for preparing an object to be processed, characterized in that the chemical contains an aqueous solution containing divalent iron ions and trivalent iron ions.   The object according to claim 10, further comprising heating means for heating the mixture of the granular material and the drug and / or evaporation means for evaporating water from the mixture of the granular material and the drug. Processed product preparation equipment. An apparatus for preparing an object to be processed according to claim 10 or 11,
A magnetic separator for magnetically sorting the workpiece to be obtained via the preparation device of the workpiece;
The processing apparatus of the granular material characterized by including.   The apparatus for treating granular material according to claim 12, wherein the granular material is soil.

Images