JP2020128982A - Method and device for preparing treatment target matter, and method and device for treating granules - Google Patents

Abstract

To provide a method of treating granules through a simple procedure at low cost without producing extra waste.SOLUTION: A granule treatment method is provided, comprising: a drug adding step (step S1-a) for adding a drug containing an aqueous solution containing divalent iron ions and an alkaline agent to granules; a heating step (step S1-b) for heating the mixture of the granules and the drug; a step (step S1) for generating and adsorbing a magnetic substance on surfaces of the granules; and a sorting step (step S2) for sorting the granules having the magnetic substance generated and adsorbed on the surfaces thereof by magnetic sorting.SELECTED DRAWING: Figure 1

Description

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

Due to the Fukushima Daiichi Nuclear Power Plant accident that started after the Great East Japan Earthquake, the scattering of radioactive materials (especially radioactive cesium, hereafter radioactive Cs) to the area around the nuclear power plant caused serious environmental problems. Radioactive Cs released from the nuclear power plant was deposited on soil by rainfall, and they took the form of (I) humic substances and ion adsorption on the surface of soil particles, or (II) trapped inside 2:1 type clay. Most of the radioactive Cs in the adsorbed form of (I) in recent years are also stabilized as form (II), and the contaminated soil in the temporary storage area (approximate 22 million tons, of which 2/3 is farmland soil) is an intermediate storage facility. It is considered unrealistic to bring all of them into the soil, and in the future, there is an urgent need to develop a volume-reducing technology capable of miniaturizing the contaminated soil of the form (II).

Under such circumstances, the development trend of decontamination technology after the accident is roughly divided into three. The first category is the "extraction/adsorption method" category. Recently, since the proportion of the above-mentioned form (II) has increased and extraction of radioactive Cs has become extremely difficult, a technique for extracting and separating dissolved Cs by performing soil disintegration in a subcritical state has also been developed. However, the subcritical method has a problem that it cannot obtain a sufficient processing amount because it is a batch method.

On the other hand, a technology for removing the radioactive Cs adsorbed on the soil particles together with the soil particles has been advanced. Among them, the "micro bubble flotation/classification method" is a typical example (second category). Recently, as a more advanced suspension water treatment technique, a technique for separating fine particles of soil in wastewater by a superconducting magnetic separation method has been proposed. These are unsuitable for large-scale wastewater treatment in the downstream of the process and unsuitable for treatment of agricultural soil containing a lot of root hairs, and the latter has problems in cost and treatment amount.

The third category includes dry treatments such as "heat separation" or "heat reduction" treatments. For example, there is a method in which a soil amount of _1/2 to an equivalent amount of CaCl ₂ is added to contaminated soil containing biotite as a main component, and the mixture is heated at a temperature of slightly 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.

Different from the above decontamination technology, there is a method of decontaminating by classifying dry soil with 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 separated to classify the contaminated soil. The soil contaminated with radioactive Cs has a higher concentration of radioactive Cs as the particle size is smaller, so decontamination can be performed by removing the contaminated soil with a small particle size.

JP, 2017-39123, A JP, 2017-113744, A

The method described in Patent Document 1 or Patent Document 2 is considered to be a simple and excellent method in that no extra waste is newly generated including wastewater and the like, but this method produces dust because it is a dry method. It is necessary to take measures easily. Further, since the contaminated soil contains wood chips, root hairs, etc., it is necessary to treat them as well.

An object of the present invention is to provide a method and apparatus for treating powder and granules which can be carried out inexpensively by a simple operation without generating extra waste, and a method for preparing an object to be treated which can be used in the method for treating powder and granules. And to provide a device.

The present invention is a method for magnetically selecting an object to be treated, wherein the object to be treated is a powder and granules, and the powder and the granules coexist with divalent iron ions and trivalent iron ions. A heating step of heating it in a state, wherein the divalent iron ion is given as an aqueous solution containing the divalent iron ion, and a magnetic substance is produced and adsorbed on the surface of the granular material. It is a method of preparing an object to be treated.

In the method for preparing an object to be treated according to the present invention, the trivalent iron ion is derived from an iron component contained in the powder and/or a divalent iron ion contained in the aqueous solution. It is characterized by being a thing.

In the method for preparing an object to be treated of the present invention, the trivalent iron ion is provided as an aqueous solution containing the trivalent iron ion.

In the method for preparing an article to be treated of the present invention, the aqueous solution containing divalent iron ions contains an alkaline agent, or in the method for preparing the article to be treated according to the present invention, an aqueous solution containing the divalent iron ions. And/or an aqueous solution containing trivalent iron ions is characterized by containing an alkaline agent.

In the method for preparing an object to be treated of the present invention, the temperature in the heating step is 200° C. or higher and 300° C. or lower.

In the method for preparing an object to be treated according to the present invention, the powder or granular material contains an organic matter, the organic matter is carbonized in the heating step, and the magnetic substance is produced and adsorbed on the surface of the carbide.

In the method for preparing an object to be treated of the present invention, when the aqueous solution containing the divalent iron ion and/or the aqueous solution containing the trivalent iron ion or the aqueous solution containing an alkaline agent is used as a drug, By controlling one or more of the group (A), the magnetic attraction force of the magnetic substance generated and adsorbed on the surface of the powdery or granular material is controlled.
(A) Divalent iron ion concentration, ratio of trivalent iron ion to divalent iron ion, type of alkaline agent, concentration of alkaline agent, addition amount of drug, stirring strength for mixture of powder and granules , Standing time after drug addition, heating temperature, heating time, heating rate, type of anion in aqueous solution

The present invention is the method for treating powdery or granular material, comprising a classification step of classifying the object to be treated obtained by the method for preparing the object to be treated by magnetic force selection.

In the method for treating a granular material of the present invention, the granular material is soil.

The present invention relates to a reaction device that heats a drug and a powder or granular material that is an object to be processed in the coexistence state to generate and adsorb a magnetic substance on the surface of the powder or granular material, and a drug that supplies the drug to the reaction device. A supply device and a preparation device for an object to be treated, characterized in that, as the chemical, an aqueous solution containing at least divalent iron ions is contained.

The present invention is a powdery or granular material processing apparatus, comprising: the apparatus for preparing a material to be processed; and a magnetic separator for magnetically selecting an object to be processed obtained through the apparatus for preparing a material to be processed. is there.

In the apparatus for treating powder and granules of the present invention, the powder and granules are soil.

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

It is a flow figure explaining the processing method of the granular material as one embodiment of the present invention. It is a block diagram of the processing apparatus 1 of the granular material as one Embodiment of this invention. It is a schematic diagram which shows the point of the magnetic force selection implemented in the Example of this invention. The decomposed granite soil in the processing method of the granular material of the present invention is an experimental data showing the relationship between the added amount and the magnetically attracted rate increase ratio of FeCl 2 · _4H 2 _O when the test soil. The decomposed granite soil in the processing method of the granular material of the present invention is an experimental data showing the relationship between the added amount and the magnetically attracted rate increase ratio of FeCl ₃ when the test soil. 7 is experimental data showing the relationship between the type of alkaline agent and the ratio of increase in magnetic sticking rate when using sand sand as the test soil in the method for treating powder and granular material of the present invention. It is an experimental data which shows the relationship between the amount of addition of NaOH and the magnetic sticking rate increase ratio when the sand sand is used as the test soil in the method for treating powder and granular material of the present invention. It is experimental data which shows the relationship between the addition order of a chemical|medical agent and a magnetic-adhesion rate increase ratio when the sand sand is used as a test soil in the processing method of the granular material of this invention. It is an experimental data which shows the relationship between the amount of addition of a chemical|medical agent and the magnetic-adhesion-ratio increase ratio when the sand sand is used as a test soil in the processing method of the granular material of this invention. It is experimental data which shows the relationship between the stirring means and the magnetic sorption rate increase ratio when the sand sand is used as the test soil in the method for treating powder and granules of the present invention. 7 is an experimental data showing a relationship between a standing time before a heating operation after addition of a chemical agent and a magnetic sticking rate increase ratio when a sand sand is used as a test soil in the method for treating a granular material of the present invention. It is experimental data which shows the relationship between the heating temperature and the magnetic sorption rate increase ratio when the sand sand is used as the test soil in the method for treating a granular material of the present invention. It is experimental data which shows the relationship between the heating time and the magnetic sticking rate when the sand sand is used as the test soil in the method for treating powder and granules of the present invention. It is experimental data which shows the relationship between a temperature rising rate and a magnetic sticking rate when the sand sand is used as a test soil in the method for treating a granular material of the present invention. It is experimental data which shows the relationship between the kind of counter anion and the magnetic-adhesion rate increase ratio when the sand-sand is used as a test soil in the method of treating a granular material of the present invention. It is experimental data which shows the relationship between the amount of addition of Fe ²⁺ and the ratio of increase in magnetic sticking rate when the sand sand is used as the test soil in the method for treating a granular material of the present invention. It is a particle size distribution measurement result before and after heating of black soil which is a test soil in the method of treating a granular material of the present invention. The black soil in the processing method of the granular material of the present invention is an experimental data showing the relationship between the added amount and the magnetically attracted increasing rate of FeCl 2 · _4H 2 _O when the test soil. It is experimental data which shows the relationship between the amount of addition of NaOH and the rate of increase of magnetic sticking when black soil is used as a test soil in the method for treating a granular material of the present invention.

FIG. 1 is a flow chart illustrating a method of treating powdery or granular material according to an embodiment of the present invention. The method for treating powdery or granular material of the present invention can be roughly divided into two steps, a front stage and a rear stage. The first step is a step (step S1) of preparing a powder or granular material (powder or granular material) that is an object to be magnetically sorted, and the second step is magnetically sorting of the powder or granular material prepared in the previous step to be magnetically selectable. It is a magnetic force sorting step (step S2) of sorting into magnetic and non-magnetic substances.

Specifically, the process of magnetically sorting powders and granules is a process of generating and adsorbing a magnetic substance that can be adsorbed by a magnet on the surface of the powder or granular substance (magnetic substance generation and adsorption process). The method includes a medicine adding step (step S1-a) of adding a medicine and a heating step (step S1-b) of heating a mixture of the medicine and powder.

In this treatment method, the granular material that is the object to be treated is not particularly limited, and as the granular material, soil, incineration ash, sludge, a mixture thereof, and a substance to which contaminants adhere, adsorb or adhere Is mentioned. Examples of pollutants include heavy metals, dioxins, PCBs, persistent organic pollutants (POPs) such as 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 polluted soil in which pollutants are mainly fixed, adsorbed or attached to the surface of the soil, the smaller the particle size, the higher the pollutant concentration (for example, refer to Table 1 described in the specification of Japanese Patent No. 5313387). .. 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 force selection as described below, it is possible to separate and decontaminate highly concentrated contaminated soil.

The particle size of the powder or granular material is not particularly limited, but the present treatment method can be suitably used for the processing of the powder or granular material which is difficult to screen. The water content of the granular material is not particularly limited. Even if it is in an absolutely dry state or a powder containing water, it can be directly processed. Even if the water content is large, the water content is heated in the heating step to evaporate, but the more water content, the more energy is required to evaporate it. If the powdery or granular material can be dehydrated, it is preferable to perform dehydration in advance to reduce the water content.

The granular material may include a lumpy material. As shown in Examples described later, when a stirring operation was performed on the mixture of the powdery particles and the drug, the magnetic sticking rate decreased in the magnetic force selection step, and the larger the stirring strength, the lower the magnetic sticking rate. From this, it is preferable to crush such a lump in the previous stage.

In addition, when crushing the lumps, it is preferable to carry out so as not to crush the powder and granules other than the lumps. As described above, in the contaminated soil in which the pollutant is mainly adhered to, adsorbed on, or adhered to the surface of the soil, the larger the particle size, the lower the concentration of the pollutant. When such a contaminated soil having a large particle size is pulverized, a contaminated soil having a low pollution concentration and a small particle size is generated, so that the decontamination efficiency decreases.

In addition, some of the particles include organic matter such as plants, leaves, wood waste, and root hair, and such particles can also be treated by the present treatment method. Since the method for treating a granular material according to the present embodiment includes a heating step, the organic matter becomes a carbide in this heating step.

In the present invention, divalent iron ion Fe ²⁺ and trivalent iron ion Fe ³⁺ are used for the production of the magnetic substance. Although divalent iron ion Fe ²⁺ is supplied as a drug, there are a plurality of modes of supplying trivalent iron ion Fe ³⁺ . Therefore, the drug to be used differs depending on the supply mode of the trivalent iron ion Fe ³⁺ .

Specifically, when the trivalent iron ion Fe ³⁺ is obtained from the granular material which is the object to be treated and/or a part of the divalent iron ion Fe ²⁺ supplied as a chemical is chemically changed, the trivalent iron is When the ions become Fe ³⁺ , an aqueous solution containing divalent iron ion Fe ²⁺ is used as a drug. When trivalent iron ion Fe ³⁺ cannot be obtained from the granular material that is the object to be treated and/or a predetermined amount of trivalent iron ion Fe ³⁺ cannot be obtained from the divalent iron ion Fe ²⁺ supplied as a drug. Occasionally, an aqueous solution containing divalent iron ion Fe ²⁺ and trivalent iron ion Fe ³⁺ is used as a drug.

The aqueous solution containing divalent iron ion Fe ²⁺ and the aqueous solution containing trivalent iron ion Fe ³⁺ are not particularly limited, but an aqueous solution containing FeCl ₂ .4H ₂ O and FeCl ₃ is preferable. In addition to FeCl ₂ .4H ₂ O, FeSO ₄ .7H ₂ O, Fe(NH ₄ ) ₂ (SO ₄ ) ₂ .6H ₂ O and the like are examples of the drug containing divalent iron ions Fe ²⁺ . These iron salts have different solubility in water and unit price. FeCl ₂ .4H ₂ O is preferable because its solubility is greater than that of other iron salts and therefore the concentration can be easily adjusted and the unit price is low.

The concentration of the divalent iron ion Fe ²⁺ and/or the trivalent iron ion Fe ³⁺ influences the magnetic adhesion force of the magnetic substance generated/adsorbed on the surface of the granular material. As shown in Examples described later, the magnetic sticking rate peaked when the divalent iron ion Fe ²⁺ in the aqueous solution had a specific concentration. On the other hand, in the relationship between the concentration of trivalent iron ions Fe ³⁺ and the ratio of increase in magnetic attachment rate, the higher the concentration of trivalent iron ions Fe ³⁺ , the lower the magnetic attachment rate.

The magnetic cohesive force of the magnetic substance generated/adsorbed on the surface of the granular material correlates with the particle size and cohesiveness of the magnetic substance, and further the amount of generation/adsorption, so that the divalent iron ion Fe ²⁺ and/or the trivalent iron ion It is considered that these change depending on the concentration of iron ions Fe ³⁺ . By adjusting the proportion of bivalent concentration of iron ions ^{Fe 2+} of an aqueous solution, the trivalent concentration of iron ions ^{Fe 3+} of the divalent iron ions ^{Fe 2+} and trivalent iron ions ^{Fe 3+} from the above A desired magnetic sticking rate can be obtained.

The amount of the drug added to the powder or granular material, that is, the amount of the divalent iron ion Fe ²⁺ and/or the trivalent iron ion Fe ³⁺ , also greatly affects the magnetic sticking rate. As shown in Examples described later, the magnetic sticking rate increased in proportion to the amount of the drug added. This can be said to indicate that the amount of magnetic substance produced/adsorbed and the magnetic adhesion force are increased in proportion to the amount of addition of the divalent iron ion Fe ²⁺ and/or the trivalent iron ion Fe ³⁺ . From the above, it is possible to obtain a desired magnetic sticking rate by adjusting the amount of the drug added to the powder or granular material. Regarding the relationship between the added amount of the drug and the type of soil, it is necessary to increase the added amount of the drug as the content of the organic matter contained in the soil increases, as judged from Examples described later.

Further, in the drug addition step, a pH adjuster is added as a drug. Here, the pH adjuster is an alkaline agent and is added in the state of an aqueous solution. The alkaline agent is not particularly limited, but sodium hydroxide NaOH is preferable in view of the fact that the magnetic sticking rate can be increased, the unit price, the availability, etc., as shown in the examples described later. The addition amount of the alkaline agent has a great influence on the magnetic sticking rate, as shown in Examples described later. From the above, it is possible to obtain a desired magnetic sticking rate by adjusting the type and addition amount of the alkaline agent.

When trivalent iron ion Fe ³⁺ is supplied as a drug, the following method can be considered. Aqueous solution containing divalent iron ion Fe ^{2+ prepared} by adding a predetermined amount of divalent iron salt and alkaline agent to water, and trivalent iron prepared by adding a predetermined amount of trivalent iron salt and alkaline agent to water Separately ^prepare an aqueous solution containing ions Fe ³⁺ and add them separately. Alternatively, these two aqueous solutions are mixed in advance and then added to the granular material. Further, an aqueous solution containing divalent iron ion Fe ²⁺ and trivalent iron ion Fe ³⁺ prepared by adding a predetermined amount of divalent iron salt, trivalent iron salt and an alkaline agent to water is added to the granular material. ..

As described in Examples below, a method of separately adding an aqueous solution containing divalent iron ions Fe ²⁺ and an aqueous solution containing trivalent iron ions Fe ³⁺ is a method of adding divalent iron ions Fe ²⁺ and trivalent iron ions. The magnetic sticking rate was lower than the method of adding together iron ions Fe ³⁺ . Considering the mixing after adding the drug to the granular material, when supplying the trivalent iron ion Fe ³⁺ as the drug, the divalent iron ion Fe ²⁺ and the trivalent iron ion Fe ³⁺ are combined together. It is good to add.

The liquid amount of the drug added to the powder or granular material is preferably such that the liquid slightly floats on the surface of the powder or granular material. In other words, it is preferable that when the chemical is added to the powder or granules to be treated, the powder or granules are wholly immersed in the liquid. In this way, the powder and granules can be reliably brought into contact with the drug, and it is not necessary to carry out a stirring operation. On the other hand, even if the amount of the chemical to be added is increased more than necessary, it is uneconomical because water is evaporated in the heating step.

When the liquid amount of the drug to be added to the powder or granules is reduced, it is necessary to perform an agitation and mixing operation for making the drug and the powder or granules uniform. This stirring and mixing operation may be performed in parallel with the chemical addition, after the chemical addition, or in the heating step. The device and the stirring method used for stirring and mixing are not particularly limited, but it is preferable that the powder and granular material is not crushed by the stirring operation and that dust is not generated.

The heating step (step S1-b) is a step of heating the mixture of the drug and the powder or granular material. As shown in Examples described later, the magnetic sticking rate increases in proportion to the heating temperature, but decreases above 300° C. conversely. Further, if the heating temperature exceeds 350° C., there is a concern that dioxin will be resynthesized. From these, the heating temperature is preferably 200° C. or higher and 300° C. or lower, more preferably 250° C. or higher and 300° C. or lower, and even more preferably around 250° C. If the heating temperature is 350° C. or lower, there is no concern about loss of magnetite magnetism (Curie point: 858K).

The heating operation in the heating step is not particularly limited, but after the drug is added to the powder or granular material, the standing time (standing time) until the start of heating, the rate of temperature increase from room temperature to the predetermined heating temperature are reached. The magnetic sticking rate varies depending on the time (heating time) for holding the heating temperature after reaching the predetermined heating temperature. As shown in Examples described later, when the stationary time was lengthened or the temperature rising rate was increased, the magnetic sticking rate decreased. If the heating time was 30 minutes or more, the magnetic sticking rate was almost constant regardless of the heating time. From the above, in the heating operation, the magnetic sticking rate can be adjusted by adjusting the stationary time (standing time), the temperature rising rate, and the heating time after the chemicals are added to the powder and granules until the heating is started.

In the heating step, it is preferable to use a stirring and mixing operation in combination from the viewpoint of making the temperature uniform, removing water, and further preventing aggregation of the powder and granules. Also here, it is preferable to stir and mix so that the powdery particles are not crushed. The heating temperature and heating time in the heating step are basically set so that the magnetic coercive force of the magnetic substance has a desired value. However, when the powdery or granular material contains an organic substance, the organic substance is carbonized and It is preferable to determine the heating temperature and the heating time so that the magnetic substance is generated and adsorbed on the surface.

The particle size and dispersibility of the magnetic substance generated and adsorbed on the surface of the powder and granules depend not only on the temperature and time in the heating process, but also on the atmosphere of the reaction field, specifically whether the reaction field is an oxidizing atmosphere or a reducing atmosphere. to be influenced. This affects that the divalent iron ion Fe ²⁺ is oxidized and changed to the trivalent iron ion Fe ³⁺ . Therefore, the magnetic sticking rate can be adjusted by adjusting the atmosphere of the reaction field in the heating step.

The mechanism by which the magnetic substance is generated and adsorbed on the surface of the granular material in the magnetic substance generation and adsorption step having the above-described structure is considered as follows. Hereinafter, the granular material will be described as soil.

When a chemical is added to the soil, ion exchange between the monovalent ion species in the soil and the divalent iron ion Fe ²⁺ or the trivalent iron ion Fe ³⁺ is performed. Then, a chemical reaction occurs on the soil surface to generate a magnetic substance on the soil surface, and the magnetic substance is adsorbed on the soil surface.

It is known that the cation exchange capacity (CEO) of 2:1 type clay minerals and 1:1 type clay minerals is at least about 80 times larger in the former case. Therefore, divalent iron ion Fe ²⁺ and trivalent iron ion Fe ³⁺ are preferentially adsorbed on the 2:1 type clay mineral, and magnetic substances are also preferentially generated and adsorbed on the surface of the 2:1 type clay mineral. To do.

As described in the section of the background art, radioactive Cs released by the nuclear accident is deposited on the soil due to rainfall, and finally captured inside the 2:1 type clay. From this, it is understood that the magnetic substance generation and adsorption step shown in the present embodiment, and further the method for treating powder and granules shown in the present embodiment can be suitably used for treatment of soil contaminated with radioactive Cs.

In the present method for treating powder and granules, the powder and granules obtained through the magnetic substance generation and adsorption step are subjected to magnetic force selection in the next step, so that in the magnetic substance generation and adsorption step, a magnetic material suitable for magnetic force selection is obtained. A method capable of producing and efficiently producing it is preferable. In this respect, the magnetic substance obtained by the present method can be controlled in magnetic attraction, and the magnetic substance generation/adsorption step is simple, which is a preferable method.

From the viewpoint of magnetic force selection, it is preferable that the magnetic substance generated and adsorbed on the surface of the granular material has a small particle size and is uniformly dispersed on the surface. Further, it is preferable that the amount of the drug used for generating and adsorbing the magnetic substance is small.

By controlling one or more of the following (A) groups as shown in the above-mentioned or later-described examples, it is possible to control the magnetic adhesion force of the magnetic substance generated on the surface of the powder or granular material. The conditions of the magnetic substance generation/adsorption step may be appropriately set according to the characteristics of the object to be treated such as the content and the content of the organic matter, and the target magnetic sticking rate.
(A) Divalent iron ion concentration, ratio of trivalent iron ion to divalent iron ion, type of alkaline agent, concentration of alkaline agent, addition amount of drug, stirring strength for mixture of powder and granules , Standing time after drug addition, heating temperature, heating time, heating rate, type of anion in aqueous solution

The magnetic force sorting step (step S2) magnetically sorts the powder or granular material in which the magnetic substance is generated/adsorbed on the surface obtained through the previous step (step S1). The magnetic separator and the magnetic separation method used in the magnetic force selection step are not particularly limited, and a known magnetic separator and magnetic separation method can be used. Depending on the magnetic separator and the magnetic separation method, it may not be possible to process a high temperature magnetic separation target. In such a case, a cooling step may be provided between the magnetic substance generation and adsorption step and the magnetic force selection step to cool the magnetic material to be magnetically selected (powder or granular material).

The outline of the processing mechanism of the present processing method having the above configuration is as follows. In the magnetic substance generation/adsorption step, the amount of the magnetic substance generated/adsorbed to the powder/granule (per unit mass of the powder/granule) increases as the powder/granule having a smaller particle size is concerned. In the magnetic force selection step, the powder particles having a small particle size have a small self-weight, and moreover, a large amount of magnetic substances are produced/adsorbed, and thus become a magnetic substance. On the other hand, a powder having a large particle diameter has a large self-weight and a small amount of magnetic substance produced/adsorbed, so that it becomes a non-magnetic substance.

As described above, in the magnetic substance generation/adsorption step of the powder or granular material, the powder or granular material can be classified by generating and adsorbing the magnetic material and magnetically selecting the magnetic material. Since radioactive contaminant-contaminated soil has a higher concentration of pollutants as the particle size is smaller, it is possible to concentrate and decontaminate radioactive contaminants by treating radioactive-contaminated soil using this treatment method. ..

In the present treatment method, the organic matter contained in the granular material becomes a carbide in the heating step (step S1-b), so that the volume of the object to be treated is reduced. Further, at the stage of the magnetic substance generation and adsorption step, the magnetic substance is also generated and adsorbed on the surface of the carbide. Since the carbide has a lower density than that of the contaminated soil, it becomes a magnetic substance in the magnetic separation process.

The method for treating powder or granules of the present invention can be variously modified based on the method for treating powder or granules of the above-described embodiment. Hereinafter, a modified example of the method for treating powder and granules will be described.

In the method for treating powder or granular material according to the above-described embodiment, the powder or granular material is used as it is as the object to be treated, but prior to the present treatment method, the powder or granular material is classified using a sieve or the like to remove one having a large particle diameter. May be. It is known that in a radioactive substance-contaminated soil, the smaller the particle size, the higher the radioactive substance concentration, and conversely, the coarse-grained radioactive substance concentration is relatively low (for example, in the specification of Japanese Patent No. 5313387). See Table 1). Therefore, if the coarse particles are removed in advance and the remaining contaminated soil is magnetically selected, the radioactive contaminants can be efficiently concentrated and decontaminated.

Next, a powdery or granular material processing apparatus 1 according to an embodiment of the present invention will be described. FIG. 2 is a configuration diagram of the powdery or granular material processing apparatus 1 of the present invention. Hereinafter, assuming that the granular material is radioactive substance contaminated soil (hereinafter referred to as contaminated soil), the configuration of the granular material processing device will be described.

The powdery or granular material processing apparatus 1 of the present invention is a continuous processing apparatus for continuously processing contaminated soil, and supplies chemicals to the reaction apparatus 31 and the reaction apparatus 31 for producing and adsorbing a magnetic substance on the surface of the contaminated soil. It includes a chemical supply device 21, a contaminated soil supply device 11 for supplying contaminated soil to the reaction device 31, a cooling device 41 for cooling the contaminated soil after the reaction, and a magnetic force selection device 51 for magnetically selecting the contaminated soil after cooling.

The contaminated soil supply device 11 is a device for quantitatively supplying contaminated soil to the reaction device 31, and is a screw feeder 13 with a hopper 12. As a quantitative supply device for powder and granular material, there is a table feeder and the like in addition to the screw feeder. Here, the type or the like is not particularly limited as long as the contaminated soil can be quantitatively supplied, but it is preferable that the granular material is not crushed or crushed during the transportation process and the surface is not scraped.

The drug supply device 21 is a device for quantitatively supplying a drug to the reaction device 31, and includes a drug supply tank 22 having an agitator 23, and a fixed amount supply pump 24. The chemical supply tank 22 is filled with an aqueous solution in which a divalent iron salt and an alkaline agent are dissolved in water.

In the treatment apparatus 1 for powder and granular material of the present embodiment, the trivalent iron ion Fe ³⁺ is not contained in the chemical agent because the contaminated soil and the divalent iron ion Fe ²⁺ are oxidized and supplied. When trivalent iron ion Fe ³⁺ is insufficient in the contaminated soil and the oxidation of divalent iron ion Fe ²⁺ , the trivalent iron salt may be supplied via the chemical supply device 21.

In addition, in the present embodiment, since a chemical that allows the contaminated soil to soak is added to the contaminated soil, the contaminated soil and the chemical are supplied to the reaction device 31 without passing through a device that mixes the contaminated soil and the chemical. When the amount of the drug supplied to the soil is small, the contaminated soil and the drug may be mixed by the mixing device and supplied to the reaction device 31.

The reaction device 31 is a device that heats a mixture of contaminated soil and a drug to cause the drug to react and generate and adsorb a magnetic substance on the surface of the contaminated soil. The reaction device 31 is an indirect heating type rotary kiln including an inner cylinder 32 that is connected to a drive device (not shown) and rotates, and an outer cylinder 37 that is fixed so as to cover the inner cylinder 32.

The inner cylinder 32 is provided at one end with an inlet 33 for receiving the contaminated soil supplied from the contaminated soil supply device 11 and the medicine supplied from the medicine supply device 21, and at the other end for discharging the heated mixture. An outlet hood 34 is provided. A weir (not shown) is provided in a portion of the inner cylinder 32 near the inlet 33 to prevent the supplied medicine from immediately moving to the outlet hood 34 side. The supplied contaminated soil moves over the weir and moves to the outlet hood 34 side as the inner cylinder 32 rotates.

The inlet part 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 gas such as water vapor generated by heating the mixture 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 is divided into three in the longitudinal direction, and a heating gas supply port 38 and a discharge port 39 are provided in each section, and receives a heating gas sent from a heating gas supply device (not shown). The mixture in the inner cylinder 32 is heated using this as a heating medium. By supplying heating gas having different temperatures to the respective compartments, the mixture and the contaminated soil in the inner cylinder 32 can be adjusted to desired temperatures and temperature distributions.

The mixture of the contaminated soil and the medicine is supplied to the inner cylinder 32 in a slurry state, and in the process of moving from the inlet portion 33 of the inner cylinder 32 to the discharge port 36, is heated at a predetermined temperature for a predetermined time, and is then transferred to the surface of the contaminated soil. Generates and adsorbs magnetic substances. The polluted soil on the surface of which the magnetic substance is generated/adsorbed is discharged from the discharge port 36. On the other hand, gas such as water vapor generated along with the heating operation of the mixture of the contaminated soil and the chemical is introduced from the exhaust port 35 to an exhaust gas treatment device (not shown).

The reactor 31 is only required to heat the mixture of the contaminated soil and the drug at a predetermined temperature for a predetermined time to generate and adsorb a magnetic substance on the surface of the contaminated soil, and the type of the device is not particularly limited. However, those having a stirring and mixing function in terms of uniformity of reactivity and temperature and prevention of aggregation of contaminated soil are preferable. At this time, it is preferable that the contaminated soil is not crushed or crushed and the surface is not scraped off. From this point, the rotary kiln can be said to be a preferable device.

The cooling device 41 cools the contaminated soil in which the magnetic substance is generated and adsorbed on the surface discharged from the reaction device 31, to a temperature at which it can be supplied to the magnetic force sorting device 51 in the subsequent stage. The cooling device 41 is a horizontal uniaxial stirring device with a jacket, a horizontal uniaxial screw 43 is provided in the 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.

At the outlet of the stirring tank 42, a rotary feeder 46 is provided as a device for quantitatively supplying the cooled contaminated soil to the magnetic sorting device 51 in the subsequent stage.

The cooling device 41 is not particularly limited in its type and the like as long as it can cool the contaminated soil in which the magnetic substance is generated and adsorbed on the surface discharged from the reaction device 31 to a temperature at which it can be supplied to the magnetic separation device 51 in the subsequent stage. is not. Further, the quantitative supply device for quantitatively supplying the cooled contaminated soil to the magnetic force sorting device 51 is not limited to the rotary feeder 46, but it is preferable that the contaminated soil is not crushed/crushed and the surface is not scraped off. ..

The magnetic force sorting device 51 magnetically sorts the contaminated soil quantitatively supplied through the rotary feeder 46. The magnetic force sorting device 51 shown here is a known conveyor type magnetic separator, and classifies contaminated soil into magnetic and non-magnetic substances. Here, the magnetic force sorting device 51 is not limited to the specific magnetic force sorting device 51, and various magnetic force sorting devices such as a drum type magnetic separator and a magnetic separator capable of separating contaminated soil into three or more can be used.

Next, a procedure for treating contaminated soil by the powdery or granular material treating apparatus 1 shown in FIG. 2 will be described.

The contaminated soil and the chemical are sent to the inner cylinder 32 via the inlet 33 of the reaction device 31 in a slurry state. The contaminated soil and the mixture of chemicals are heated while moving the inner cylinder 32 from the inlet portion 33 toward the outlet 36. During this process, the chemicals react and magnetic substances are produced and adsorbed on the surface of the contaminated soil. When the contaminated soil contains plants such as root hair, these become carbides in the reaction device 31, and a magnetic substance is generated and adsorbed on the surface like the contaminated soil. The polluted soil on the surface of which the magnetic substance is generated/adsorbed is sent to the cooling device 41 connected to the discharge port 36. Gas such as water vapor generated in the process of heating the mixture is introduced from an exhaust port 35 to an exhaust gas treatment device (not shown).

The contaminated soil in which the magnetic substance is generated and adsorbed on the surface discharged from the reaction device 31 is cooled by the cooling device 41 to a temperature at which it can be supplied to the magnetic force sorting device 51, and then is fed to the magnetic force sorting device 51 via the rotary feeder 46. It is supplied in a fixed amount and is separated into a magnetic substance and a non-magnetic substance here.

Due to the relationship of the specific surface area, the amount of magnetic substances produced/adsorbed (per unit mass of contaminated soil) increases in contaminated soil having a smaller particle size. In addition, contaminated soil with a small particle size has a small self-weight, and since it produces and adsorbs a large amount of magnetic substances, it becomes a magnetic substance. On the other hand, contaminated soil with a large particle size becomes a non-magnetic substance because its own weight is large and the amount of magnetic substances produced/adsorbed is small.

As described above, by using the powdery or granular material processing apparatus 1, the contaminated soil can be sorted according to the particle size, that is, the classification can be performed. The radioactive substance-contaminated soil can be decontaminated by using the treatment apparatus 1 because the soil having a smaller particle size has a higher concentration of the radioactive substance.

The processing apparatus for powder or granular material of the present invention is not limited to the processing apparatus shown in FIG. 2 includes a cooling device 41 to cool the contaminated soil discharged from the reaction device 31, but the temperature of the contaminated soil discharged from the reaction device 31 is equal to that of the magnetic separation device 51. If it satisfies the specifications, the cooling device 41 is unnecessary. In such a case, a fixed amount supply device such as a rotary feeder may be installed at the discharge port 36 of the reaction device 31.

When controlling the generation/adsorption amount of the magnetic substance to be generated/adsorbed on the surface of the contaminated soil by controlling the atmosphere of the reaction field, an atmosphere gas supply pipe for supplying gas into the reaction apparatus is provided, From this, air, nitrogen gas, combustion exhaust gas, carbon dioxide gas, or a mixture of these gases may be supplied.

The powdery or granular material processing apparatus of the present invention is not limited to the continuous processing apparatus, and may be a semi-batch processing apparatus or a batch processing apparatus.

As shown in the above embodiment, by using the method and apparatus for treating a granular material of the present invention, it is possible to treat contaminated soil and the like inexpensively with a simple operation without generating extra waste. Further, the method and apparatus for preparing an object to be treated of the present invention can be suitably used as the method for treating powder and granular material of the present invention and the pretreatment method and pretreatment apparatus for the treatment apparatus.

Further, the method for preparing an object to be treated and the method for treating a granular material according to the present invention include adding a liquid chemical agent to a granular material such as contaminated soil, and reacting the chemical to generate a magnetic substance on the surface of the granular material. Since the magnetic substance is adsorbed, it is easy to uniformly generate and adsorb the magnetic substance, and the generation of dust is suppressed. Moreover, it can be said that it is a practical method and device, such that even if the contaminated soil contains wood chips, root hairs, etc., it can be treated as it is.

Further, the method for preparing an object to be treated and the method for treating a granular material according to the present invention can control the magnetic coercive force of the magnetic substance generated and adsorbed on the surface of the granular material, so that the powder can be efficiently treated with a small amount of the drug. Granules can be processed. Furthermore, this treatment method can be used for treating various powders and granules and for a wide range of applications.

Although the preferred embodiments have been described with reference to the drawings, those skilled in the art will easily think of various changes and modifications within the obvious scope by reading this specification. Therefore, such changes and modifications are construed as being within the scope of the invention defined by the claims. The present invention is not limited to the examples described below.

Test soil (mountain sand)
Mountain sand was used as the test soil. As the mountain sand, commercially available mountain sand (mass sand soil) was obtained, which was air-dried to have a water content of 1 wt% or less. As a result of determining the particle size of the sand sand by a test sieve and a wet laser method (in ethanol), the particle size over 600 μm is 61.8 wt %, the particle size less than 75 μm is 7.3 wt% and the particle size is less than 20 μm. Was 2.1 wt %. As a result of analyzing the chemical composition of the Masago soil according to JIS-M8853, ₂ wt% of Fe ₂ O ₃ was contained. Further, sand sand contained 0.19±0.06 wt% of iron sand.

Method for adjusting sample for magnetic sticking selection A typical procedure for preparing a sample for magnetic sticking selection is shown. 6 g of the chemical agent was added to 10 g of sand soil, which is a test soil, and the mixture was allowed to stand at room temperature for 5 minutes. When 6 ml of the chemical was added to 10 g of the sand sand, the sand was completely immersed in the chemical, and the chemical was slightly floated from the upper surface of the sand. Then, in the atmosphere, using a tubular furnace, the temperature was raised from room temperature to 200° C. at a rate of 18° C./min, from 200° C. to 250° C. at a rate of 5° C./min, and held at 250° C. for 2 hours. .. Then, the sample was left to cool in a desiccator, and this was used as a sample for magnetic attachment selection. The chemicals are water to which a predetermined amount of NaOH, FeCl ₃ , FeCl ₂ .4H ₂ O is added. Hereinafter, unless otherwise specified, samples for magnetic adhesion selection were prepared by the method.

Magnetic force selection method A sample is put in a dedicated mixing bottle 101 shown in FIG. 3, an iron core 102 is inserted in the upper portion of the mixing bottle 101, and a neodymium magnet (surface magnetic flux density 573 mT) 103 is attached (see FIG. 3A). The mixing bottle 101 was shaken by hand for about 30 seconds (see FIG. 3B). After that, the plastic cover 104 on the upper part of the bottle was removed, the neodymium magnet 103 and the iron core 102 were pulled out on the saucer, and the magnetic substance was collected (see FIG. 3(C)). Then, the plastic cover 104, the neodymium magnet 103, and the iron core 102 were attached, and the residue (non-magnetic material) was subjected to magnetic separation in the same manner as above. This magnetic separation operation was performed 5 times for each sample.

Definition of magnetic sticking rate and ratio of increase in magnetic sticking rate The magnetic sticking rate is expressed by equation (1). The ratio of increase in the magnetic sticking ratio is represented by the formula (2), and the magnetic sticking ratio of the blank is the magnetic sticking ratio of unsanded and unheated masago soil (hereinafter, untreated soil). The target magnetic sticking rate can also be set. For example, when the target is to classify (separate) particles having a particle size of less than 20 μm contained in the sand sand, the target magnetic sticking rate is the same as the content rate of particles having a particle size less than 20 μm contained in the sand sand. .. In the case of the sand sand used in this example, the target magnetic sticking rate is 2.1 wt% and the target magnetic sticking rate ratio is 12.3.

Magnetization rate of untreated soil The magnetism rate of the untreated soil of Masago soil was 0.186 wt %.

Effect of heating untreated soil When only sand sand was heated in the air (air atmosphere) at 250°C for 2 hours using a tubular furnace, the magnetic sticking rate increased 1.6 times compared to before heating. As a result of measuring the particle size of the sand sand soil after heating, the sand sand soil having a particle size of less than 1000 μm increased by 17.5 wt% as compared with that before heating. It is considered that the fine particles increased due to the heating and the magnetic adhesion rate increased due to the generation of the magnetic oxide.

Against FeCl ₂ · 4H ₂ O amount of influence decomposed granite soil 10g of, NaOH, was added a solution 6ml containing FeCl ₂ · 4H ₂ O and FeCl _3, 2 hours at 250 ° C. with the atmosphere, the tube furnace Heated. Then, it stood to cool and magnetic force selection was performed. NaOH contained in the solution is 1.0 mmol, and FeCl ₃ is 0.18 mmol. Regarding FeCl ₂ .4H ₂ O, the concentration was changed within the range of 0.26 to 3.58 mmol.

The results are shown in Fig. 4. Magnetically attracted increased rate ratio was changed by the addition of FeCl ₂ · 4H ₂ O. In FeCl ₂ · 4H ₂ O is 0.26~1.37mmol range, magnetically attracted rate increase ratio was increased in proportion to the amount of FeCl ₂ · 4H ₂ O. On the other hand, in the range FeCl ₂ · 4H ₂ O is 1.37～3.58Mmol, magnetically attracted rate increase ratio in proportion to the amount of FeCl ₂ · 4H ₂ O was reduced. The ratio of increase in magnetic sticking ratio peaked at an addition amount of FeCl ₂ .4H ₂ O of 1.37 mmol, and the value at that time was 16.5.

Effect of Addition Amount of FeCl _{3 To} 10 g of sand sand soil, 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added, and heated in a tube furnace at 250° C. for 2 hours in the atmosphere. Then, it stood to cool and magnetic force selection was performed. NaOH contained in the solution was 1.0 mmol and FeCl ₂ .4H ₂ O was 0, 1.4 and 1.6 mmol, and FeCl ₃ was changed in concentration within a range of 0 to 0.43 mmol.

The results are shown in Fig. 5. Magnetically attracted increased rate ratio, 1.4 mmol of FeCl ₂ · 4H ₂ O, when added 1.6 mmol, were both reduced in proportion to the amount of FeCl _3. When FeCl ₂ .4H ₂ O is 1.6 mmol, the addition amount of FeCl ₃ is 0 and the increase ratio of magnetic attraction ratio is 15.3, the addition amount of FeCl ₃ is 0.43 and the increase ratio of magnetic attachment ratio is about 2. there were. Comparing the case of adding 1.4 mmol of FeCl ₂ .4H ₂ O and the case of adding 1.6 mmol of FeCl ₂ .4H ₂ O, the former had a slightly higher ratio of increase in magnetic sticking ratio. When FeCl ₂ .4H ₂ O was not added, the ratio of increase in magnetic sticking ratio was approximately 2.0, which was almost constant regardless of the amount of FeCl ₃ added (0 to 0.43 mmol).

Effect of Type of Alkaline Agent To 10 g of diatomaceous earth, 6 ml of a solution containing an alkaline agent, FeCl ₂ .4H ₂ O and FeCl ₃ was added, and heated at 250° C. for 2 hours in the air using a tubular furnace. Then, it stood to cool and magnetic force selection was performed. FeCl ₂ .4H ₂ O contained in the solution was 1.61 mmol, FeCl ₃ was 0.18 mmol, and the alkaline agent was 1.0 mmol. LiOH.H ₂ O, NaOH, KOH, Be(OH) ₂ , Mg(OH) ₂ , Ba(OH) ₂ , and Al(OH) ₃ were used as the alkaline agent.

The results are shown in Fig. 6. The ratio of increase in magnetic sticking rate greatly differs depending on the type of the alkaline agent, and when NaOH was used as the alkaline agent, the ratio of increase in magnetic sticking rate was 14.8 and was the largest.

Effect of Addition Amount of NaOH To 10 g of sand sand soil, 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added, and heated at 250° C. for 2 hours using a tubular furnace in the atmosphere. Then, it stood to cool and magnetic force selection was performed. FeCl ₂ .4H ₂ O contained in the solution was 0.18 mmol, FeCl ₃ was 0.18 mmol, and NaOH was added in the range of 0 to 2.0 mmol.

The results are shown in Fig. 7. The ratio of increase in magnetic sticking rate greatly differs depending on the amount of NaOH added, and when the amount of NaOH is 1.0 mmol, the ratio of increase in magnetic sticking rate is 8.4, which is the largest.

Experiments with different order of addition of the solution (a total of 6ml) containing the impact FeCl ₂ · 4H ₂ O and FeCl ₃ of the order of addition of iron ions was carried out. In the first case, FeCl ₃ was added after adding FeCl ₂ .4H ₂ O. In the second case, FeCl ₃ was added followed by FeCl ₂ .4H ₂ O. In the third case, it was added while mixing and FeCl ₂ · 4H ₂ O and FeCl _3. The amounts of addition were 1.0 mmol for NaOH, 0.2 mmol for FeCl ₂ .4H ₂ O and 1.3 mmol for 1.3 mmol, and 0.2 mmol for FeCl _{3 with} respect to 10 g of masago soil. The heating after the addition of the chemical agent and the selection by magnetic attachment were carried out by the method described above.

The results are shown in Fig. 8. Magnetically attracted increased rate ratio, FeCl ₂ · 4H ₂ O and the FeCl ₃ were mixed highest when added simultaneously, the case of adding FeCl ₃ after adding FeCl ₂ · 4H ₂ O, increases magnetic attraction rate The ratio was the smallest. Further, the higher the concentration of FeCl ₂ .4H ₂ O, the more marked the effect of the order of addition of iron ions.

Effect of Addition Amount of Chemical Agent A solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of diatomaceous earth and heated at 250° C. for 2 hours in the air in a tubular furnace. Then, it stood to cool and magnetic force selection was performed. Here, the amount of the solution was set to 3 kinds of 6 mL, 12 mL, and 30 mL. NaOH contained in 6 mL of the solution is 1.0 mmol, and FeCl ₂ .4H ₂ O and FeCl ₃ are 0.2 mmol.

The results are shown in Fig. 9. The magnetic sticking rate increase ratio increases in proportion to the added amount of the chemical, and when 30 mL of the chemical is added to 10 g of sand sand soil, that is, 5.0 mmol of NaOH, 1 FeCl ₂ .4H ₂ O and 1 FeCl ₃ each. In the case of adding 0.0 mmol, the ratio of increase in magnetic sticking ratio was 52.

Effect of agitation The relationship between the agitation procedure after adding chemicals to the Masago soil and the ratio of increase in magnetic sticking rate was examined. 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of the sand sand soil, and the mixed solution of the sand sand soil and the drug was stirred using a stirrer before heating, or allowed to stand for 5 minutes. I put it. After that, it was heated at 250° C. for 2 hours in the atmosphere in a tubular furnace, allowed to cool, and then subjected to magnetic separation. NaOH contained in the solution is 1.0 mmol, FeCl ₂ .4H ₂ O is 1.44 mmol, and FeCl ₃ is 0.18 mmol.

A glass rod, an ultrasonic cleaner (AS ONE ASU-6M), a constant temperature water bath (yamato scientific BW101), a vortex (Thermo Fisher Scientific miniRotoS56), and a stirrer (AS ONE MN-01) were used as the stirring device.

The results are shown in Fig. 10. The magnetic sticking rate increase ratio was the largest at 22.0 when the stirring was not used, and was the smallest at 2.0 when the stirrer was used. From this result, it is understood that the higher the stirring strength, the smaller the ratio of increase in the magnetic sticking rate. This is thought to be due to the fact that the sand sand was crushed with stirring and the iron concentration per unit surface area decreased.

Effect of stationary time after addition of chemicals After the chemicals were added to the sand sand soil, the relationship between the stationary time (standing time) before heating and the increase rate of magnetic sticking rate was examined. 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of masago soil and allowed to stand in a room for a predetermined time, and then heated in a tubular furnace at 250° C. for 2 hours in the atmosphere. did. Then, it stood to cool and magnetic force selection was performed. NaOH contained in the solution is 1.0 mmol, FeCl ₂ .4H ₂ O is 1.44 mmol, and FeCl ₃ is 0.18 mmol. The standing time was 0 min, 960 min, and 1440 min.

The results are shown in Fig. 11. The increase ratio of the magnetic sticking ratio was about 20 when the heating operation was started immediately after the chemical was added to the sand sand, and it was smaller as the standing time was longer. When the operation was shifted to the heating operation after being left for 1 day, the ratio of increase in the magnetic sticking ratio was 4.3.

Effect of heating temperature The relationship between the heating temperature and the ratio of increase in magnetic sticking rate was examined. 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of sand sand soil, and the temperature was selected in the range of 80 to 350° C. by using a tubular furnace in the atmosphere, and each temperature was selected. Heated for 2 hours. The heating rate was 18°C/min from the heating temperature to 50°C, and the heating rate was 5°C/min thereafter to the heating temperature. Then, it stood to cool and magnetic force selection was performed. NaOH contained in the solution is 1.0 mmol, FeCl ₂ .4H ₂ O is 0.18 or 1.43 mmol, and FeCl ₃ is 0.18 mmol.

The results are shown in Fig. 12. Magnetically attracted increased rate ratios were increased in proportion to the temperature in the range of 80 ° C. to 300 ° C. regardless of the amount of FeCl ₂ · 4H ₂ O. When the addition amount of FeCl ₂ .4H ₂ O was 1.43 mmol, the ratio of increase in magnetic sticking ratio was 14.9 at a heating temperature of 250° C. and 18.9 at a heating temperature of 300° C. When the heating temperature exceeded 300° C., the ratio of increase in magnetic sticking ratio decreased to about 7 to 8.5. When the material to be treated contains organic matter, it can be said that the heating temperature is preferably 250° C. from the viewpoint of suppressing the generation of dioxins and carbonizing the organic matter.

Effect of heating time The effect of heating time was examined. 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of sand sand soil, and the holding time (heating time) after reaching 250° C. using a tubular furnace in the atmosphere was 0 to 3 hours. Was selected within the range, and heating was performed for each heating time. Then, it stood to cool and magnetic force selection was performed. The heating time was 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 hours. NaOH contained in the solution is 1.01 mmol, FeCl ₂ .4H ₂ O is 0.18 mmol, and FeCl ₃ is 0.18 mmol.

The results are shown in Fig. 13. The ratio of the magnetic sticking rate at each heating time to the magnetic sticking rate at the heating time of 0 hour was about 1.4 to 1.6 without much difference within the range of the heating time of 0.5 to 3.0 hours.

Effect of heating rate The effect of heating rate was investigated. 6 ml of a solution containing NaOH, FeCl ₂ .4H ₂ O and FeCl ₃ was added to 10 g of masago soil, and the temperature rising rate from room temperature to 200° C. was 1.5- It was selected within the range of 36°C/min, heated at each heating rate, and thereafter heated up to 250°C at 5°C/min. After heating at a heating temperature of 250° C. for 2 hours, the mixture was allowed to cool and magnetic separation was performed. NaOH contained in the solution is 1.01 mmol, FeCl ₂ .4H ₂ O is 1.44 mmol, and FeCl ₃ is 0.18 mmol.

The results are shown in Fig. 14. The ratio of the magnetic sticking rate at each heating rate to the magnetic sticking rate at the heating rate of 1.5° C./min tended to decrease as the heating rate increased. The magnetic sticking rate at the heating rate of 36° C./min was about 0.6 with respect to the magnetic sticking rate at the heating rate of 1.5° C./min. If the rate of temperature increase is too high, the rate of oxidation of Fe ²⁺ will increase, and there is a concern that Fe ²⁺ will be insufficient for producing the magnetic substance.

Effect of Counter Anion The relationship between the counter anion and the ratio of increase in magnetic sticking ratio was examined. 6 ml of a solution containing NaOH (1.5 mmol) and FeCl ₂ .4H ₂ O or FeSO ₄ .7H ₂ O or Fe(NH ₄ ) ₂ (SO ₄ ) ₂ .6H ₂ O was added to 10 g of sand sand soil. Then, it was heated at 250° C. for 2 hours using a tubular furnace in the atmosphere. Then, it stood to cool and magnetic force selection was performed. Fe ²⁺ contained in the solution is 0.6 mmol in each case.

The results are shown in Fig. 15. The ratio of increase in the magnetic sticking rate varied greatly depending on the type of counter anion. Magnetically attracted increased rate _ratio, when using FeSO 4 · _7H 2 O is highest 18.0, when using FeCl ₂ · 4H ₂ O was 2.8 lowest.

Effect of Fe ²⁺ addition amount of each iron salts examined the relationship between the Fe ²⁺ amount and magnetically attracted increased rate ratio at each iron salts. NaOH (1.5 mmol), FeCl ₂ .4H ₂ O (0.63 to 1.43 mmol) or FeSO ₄ .7H ₂ O (0.63 to 0.90 mmol) or Fe (NH ₄ ) with respect to 10 g of sand sand soil. ) _{2 (SO 4)} was added a solution 6ml containing _{2 · 6H 2 O (0.63mmol)} , was heated at 250 ° C. with the atmosphere, the tube furnace. Then, it stood to cool and magnetic force selection was performed.

The results are shown in Fig. 16. Since the solubility of FeCl ₂ .4H ₂ O is as large as 160 g/100 ml (at 10° C.), the addition amount can be easily adjusted and the addition amount of Fe ²⁺ can be greatly changed. Further, when FeCl ₂ .4H ₂ O is used, the ratio of increase in magnetic sticking ratio greatly differs depending on the amount of FeCl ₂ .4H ₂ O added, and is therefore preferable as a drug. FeSO ₄ · 7H ₂ O contrast, a dissolution amount of _{26g / 100ml (at20 ℃),} Fe (NH 4) 2 (SO 4) 2 · 6H 2 O are dissolved amount is 27 g / 100 ml (AT 20 C.), both of which have low solubilities, the amount of Fe ²⁺ added cannot be greatly changed.

Classification of simulated cesium-contaminated soil A simulated cesium-contaminated soil was obtained as follows. 250 ml of an aqueous cesium chloride solution having a cesium chloride CsCl concentration of 0.14 mol/L was added to 200 g of sand sand having a particle size of less than 2 mm, and air-dried overnight in a fume hood. Then, it heated with a 40-50 degreeC hotplate for 2 hours, and the water content was 1 wt% or less, and the simulated cesium contaminated soil was obtained.

Two kinds of magnetic sticking selection samples were prepared in the following manner. To 100 g of the simulated cesium-contaminated soil, 60 ml of an aqueous solution containing FeCl ₂ .4H ₂ O and NaOH was added, and heated on a hot plate at 150° C. for 2 hours to obtain a sample for magnetic attraction selection. On the other hand, in the magnetic sticking selection sample, 60 ml of the aqueous solution contains 7.2 mmol of FeCl ₂ .4H ₂ O and 15 mmol of NaOH. On the other hand, the magnetic attraction selection sample contains 8.8 mmol of FeCl ₂ .4H ₂ O and 15 mmol of NaOH in 60 ml of the aqueous solution.

An appropriate amount of each of the two types of magnetic sticking selection samples was sampled and the magnetic force was selected for each. The magnetic force selection method is as described in paragraphs [0090] and [0091] of this specification. In paragraph [0090] of the present specification, the magnetic separation operation is 5 times, but here, the magnetic separation operation was performed 10 times. Each of the magnetic substance and the residue was acid-decomposed (60° C., 120 min) and analyzed by ICP-MS. Further, the Cs concentration was calculated from the equation (3).

The results are shown in Table 1. If simulated cesium contaminated soil 100g 7.2 mmol adding FeCl ₂ · 4H ₂ O, the concentration rate (magnetically attracted material Cs concentration / residue Cs concentration), 9.6-fold, FeCl ₂ · 4H ₂ mock cesium contaminated soil 100g When 8.8 mmol of O was added, the concentration rate (magnetic substance Cs concentration/residual Cs concentration) became 5.4 times.

Test soil (black soil)
In the following experiments, black soil (organic soil) was used as the test soil. Table 2 shows the chemical composition of unheated black soil. The organic matter (loss on ignition; Ig-Loss) contained in the unheated black soil was 23%. As a result of XRD analysis of the unheated black soil, the black soil was mainly composed of quartz, albite, anorthite, soda mica, cristobalite, pyrite, allophane and the like.

The particle size distribution of the black soil (heated black soil) after heating the unheated black soil (water content 13-14 wt%) and the unheated black soil (water content 13-14 wt%) at 250° C. for 2 hours was measured. A sieve (75, 125, 250, 500, 1000 μm) was used for measuring the particle size distribution. The results are shown in Fig. 17. The unheated black soil contained 10 wt% of particles less than 75 μm, and the heated black soil contained 15 wt% of particles less than 75 μm. It is considered that the lumps were dispersed by heating and the organic matter disappeared, so that the particles of less than 75 μm increased.

Magnetic Adhesion Ratio of Chemical-Unadded Black Soil and Chemical-Unadded Heated Black Soil The magnetic adhesion ratio of non-chemical-added unheated black soil was 3.4±0.1 wt %. The magnetic sticking ratio of the heated black clay to which no chemical was added was 6.0±0.1 wt %. The heating increased the magnetic sticking rate by about 1.8 times. The fact that the black soil is heated to increase the magnetic sticking rate is the same as in the sand sand, and it is considered that the fine magnetic particles are increased by the heating and that the magnetic sticking rate is increased by the generation of the magnetic oxide. The magnetic sticking rate is represented by the formula (1), and the measuring procedure of the magnetic sticking rate was carried out based on paragraphs [0090] and [0091] of this specification.

Here, when the target is to classify the particles of less than 75 μm contained in the heated black soil to which the chemical is not added by magnetic separation, the target increase rate of magnetic adhesion is represented by the formula (4). In this example, the content of particles less than 75 μm contained in the heated black soil without addition of chemicals was 15 wt %, and the magnetic sticking rate of the heated black soil without addition of chemicals was 6.0±0.1 wt %. The rate of increase in magnetic attraction is 2.5. The rate of increase in magnetic adhesion was defined by the equation (5).

Basically, the method of adjusting the sample for magnetic attraction selection using black soil as the test soil, the method of magnetic force selection, and the definition of the magnetic attraction rate are basically the method for adjusting the sample for magnetic attraction selection using sand sand as the test soil. , The magnetic force selection method, and the definition of the magnetic attachment rate, which are as described in paragraphs [0090] to [0092] of this specification.

Effect of Addition Amount of FeCl ₂ .4H ₂ O To 10 g of black soil, a solution containing FeCl ₂ .4H ₂ O and NaOH was added, and heated at 250° C. for 2 hours in the air using a tubular furnace. Then, it stood to cool and magnetic force selection was performed. The addition amount of NaOH contained in the solution was changed to 1.5 mmol, and the addition amount of FeCl ₂ .4H ₂ O was changed in the range of 0 to 9 mmol. FeCl ₃ is not added.

The results are shown in Fig. 18. The rate of increase in magnetic adhesion changed depending on the amount of FeCl ₂ .4H ₂ O added. In FeCl ₂ · 4H ₂ O is 0~4.5mmol range, FeCl ₂ · 4H ₂ O in proportion to the added amount magnetically attached growth rate increases in amount 0.9mmol of FeCl ₂ · 4H ₂ O The increase rate of magnetic attraction was 1.03, the addition rate of FeCl ₂ .4H ₂ O was 4.5 mmol, and the increase rate of magnetic attraction was 1.15. On the other hand, FeCl ₂ · 4H ₂ O is in the range of 4.5～9.0Mmol, magnetically attached growth rate decreased in proportion to the amount of FeCl ₂ · 4H ₂ O. The increase rate of magnetic sticking reached a peak when the added amount of FeCl ₂ .4H ₂ O was 4.5 mmol.

When the relationship between the added amount of FeCl ₂ .4H ₂ O and the magnetic sticking rate was compared in the test soils, the same tendency was exhibited regardless of the test soils as shown in FIGS. 4 and 18. Specifically, the magnetic sticking rate of both the mountain sand (mass sand soil) and the black soil showed a maximum value at a certain specific amount of FeCl ₂ .4H ₂ O added.

Effect of Addition Amount of NaOH To 10 g of black soil, a solution containing FeCl ₂ .4H ₂ O and NaOH was added, and heated in a tube furnace at 250° C. for 2 hours in the air. Then, it stood to cool and magnetic force selection was performed. FeCl ₂ · 4H ₂ O contained in the solution, 4.5 mmol, NaOH was varied the amount in the range of 0～12Mmol. FeCl ₃ is not added.

The results are shown in Fig. 19. The rate of increase in magnetic adhesion changed depending on the amount of NaOH added. In the range of 0 to 9.0 mmol of NaOH, the rate of increase in magnetic attraction increases in proportion to the amount of NaOH added, and the rate of increase in magnetic attraction reaches a peak when the amount of NaOH added is 9.0 mmol. Was 2.46. On the other hand, in the range of NaOH of 9.0 to 12 mmol, the increase rate of magnetic sticking decreased in proportion to the added amount of NaOH.

Comparing the relationship between the added amount of NaOH and the magnetic adhesion rate in the test soils, the same tendency was exhibited regardless of the test soils as shown in FIGS. 7 and 19. Specifically, the magnetic sticking rates of both the mountain sand (mass sand soil) and the black soil showed the maximum value at a specific addition amount of NaOH.

Effect of Heating Temperature A solution containing NaOH and FeCl ₂ .4H ₂ O was added to 10 g of black soil, and heated at 250° C. and 300° C. in the atmosphere using a tubular furnace. The former is 18° C./min from room temperature to 200° C., the temperature is raised from 5° C./min to 200° C. to 250° C., and is held at 250° C. for 2 hours, and the latter is 18° C./min from room temperature to 200° C. The temperature was raised at 10° C./min from 200° C. to 300° C. for min and held at 300° C. for 2 hours. NaOH contained in the solution was 9.0 mmol, FeCl ₂ .4H ₂ O was 4.5 mmol, and FeCl ₃ was not added.

As a result of the experiment, when heated at 250° C. for 2 hours, the magnetic sticking rate was 14.7±0.7%, and when heated at 300° C. for 2 hours, the magnetic sticking rate was 20.5±0.4%. The increase rate of magnetic sticking was 2.4±0.1 for the former and 3.4±0.1 for the latter. At the heating temperatures of 250° C. and 300° C., the latter had a higher magnetic sticking rate.

When the relationship between the heating temperature and the magnetic susceptibility was compared in the test soils, both the mountain sand (mass sand soil) and the black soil had a higher magnetic susceptibility at the heating temperatures of 250°C and 300°C.

Effect of heating time To 10 g of black soil, a solution containing NaOH and FeCl ₂ .4H ₂ O was added, and an experiment was conducted in which the heating time was changed at 250° C. using a tubular furnace in the atmosphere. Specifically, one of them was heated from room temperature to 200° C. at 18° C./min, from 200° C. to 250° C. at 5° C./min, and kept at 250° C. for 2 hours. On the other hand, the temperature was raised from room temperature to 200° C. at 18° C./min, from 200° C. to 250° C. at 5° C./min, and kept at 250° C. for 0.5 hours. FeCl ₂ .4H ₂ O contained in the solution was 0.9 mmol, NaOH was 1.5 mmol, and FeCl ₃ was not added.

As a result of the experiment, when heated at 250° C. for 2 hours, the magnetic sticking rate was 6.2±0.2%, and when heated at 250° C. for 0.5 hour, the magnetic sticking rate was 5.5±0.1%. It was The rate of increase in magnetic adhesion was 1.0±0.0 for the former and 0.9±0.0 for the latter. When the heating time was 2 hours and 0.5 hours, the former had a slightly higher magnetic sticking rate.

When the relationship between the heating time and the magnetic sticking rate is compared in the test soil, as shown in FIG. 13, in the case of mountain sand (mass sand soil), the magnetic sticking rate of the heating time is in the range of 0.5 to 2 hours. It was hardly affected. On the other hand, in the case of black soil, the magnetic sticking rate was larger as the heating time was longer in the heating time range of 0.5 to 2 hours.

Effect of heating rate A solution containing NaOH and FeCl ₂ .4H ₂ O was added to 10 g of black soil, and an experiment was performed in the atmosphere in which a heating rate was changed up to 250°C using a tubular furnace. Specifically, one of them was heated from room temperature to 200° C. at 18° C./min, from 200° C. to 250° C. at 5° C./min, and kept at 250° C. for 2 hours. On the other hand, the temperature was raised from room temperature to 230°C at 42°C/min, from 230°C to 250°C at 4°C/min, and kept at 250°C for 2 hours. FeCl ₂ .4H ₂ O contained in the solution was 0.9 mmol, NaOH was 1.5 mmol, and FeCl ₃ was not added.

As a result of the experiment, the magnetic sticking rate was 6.2±0.2% in the former where the heating rate was slow, and 6.7±0.2% in the latter where the heating rate was fast. The rate of increase in magnetic adhesion was 1.0±0.0 for the former and 1.1±0.0 for the latter. In the experiment using black soil, there was almost no effect of the heating rate on the magnetic sticking rate.

When the relationship between the heating time and the magnetic sticking rate is compared in the test soils, as shown in FIG. 14, even in the sand (mass sand), the magnetic sticking is performed at the heating rate of 18° C./min and the heating rate of 36° C./min. The rates are about the same. Therefore, it can be said that within the range of the temperature rising rate of 18° C./min to 42° C./min, there is almost no effect of the temperature rising rate on the magnetic sticking rate regardless of the type of test soil.

1 Processing Equipment for Powder and Granules 11 Contaminated Soil Supplying Device 21 Chemical Supplying Device 31 Reactor 41 Cooling Device 51 Magnetic Sorting Device

Claims (12)

A method of magnetically sorting objects to be processed,
The object to be treated is a powder or granular material,
Including a heating step of heating the granular material in a state where divalent iron ions and trivalent iron ions coexist,
The divalent iron ion is given as an aqueous solution containing the divalent iron ion,
A method for preparing an object to be treated, characterized in that a magnetic substance is produced and adsorbed on the surface of the granular material. The trivalent iron ion is derived from an iron component contained in the granular material and/or is caused by a chemical change from the divalent iron ion contained in the aqueous solution. The method for preparing an object to be treated according to item 1. The method for preparing an object to be treated according to claim 1 or 2, wherein the trivalent iron ion is provided as an aqueous solution containing the trivalent iron ion. The method for preparing an object to be treated according to claim 1 or 2, wherein the aqueous solution containing divalent iron ions contains an alkaline agent,
Alternatively, in the method for preparing an article to be treated according to claim 3, the aqueous solution containing the divalent iron ion and/or the aqueous solution containing the trivalent iron ion contains an alkaline agent. How to prepare things. The temperature of the said heating process is 200 to 300 degreeC, The preparation method of the to-be-processed object of any one of Claim 1 to 4 characterized by the above-mentioned. The granular material contains an organic matter,
The said organic substance is carbonized by the said heating process, and the said magnetic substance produces|generates and adsorb|sucks to the surface of a carbide|carbonized material, The preparation method of the to-be-processed object of any one of the Claims 1-5 characterized by the above-mentioned. When the aqueous solution containing the divalent iron ion and/or the aqueous solution containing the trivalent iron ion or the aqueous solution containing the alkaline agent is used as a drug, one or more of the following (A) group is controlled. The method for preparing an object to be treated according to any one of claims 1 to 6, wherein the magnetic attraction force of the magnetic substance generated and adsorbed on the surface of the powder or granular material is controlled thereby.
(A) Divalent iron ion concentration, ratio of trivalent iron ion to divalent iron ion, type of alkaline agent, concentration of alkaline agent, addition amount of drug, stirring strength for mixture of powder and granules , Standing time after drug addition, heating temperature, heating time, heating rate, type of anion in aqueous solution A method for treating powdery or granular material, comprising: a classification step of classifying an object to be treated obtained by the method for preparing an object to be treated according to any one of claims 1 to 7 by magnetic separation. The method for treating powdery or granular material according to claim 8, wherein the powdery or granular material is soil. A reaction device that heats a drug and a granular material that is an object to be treated in the coexistence, and generates and adsorbs a magnetic substance on the surface of the granular material,
A drug supply device for supplying the drug to the reaction device,
Equipped with
An apparatus for preparing an object to be treated, which comprises an aqueous solution containing at least divalent iron ions as the drug. An apparatus for preparing an object to be treated according to claim 10,
A magnetic separator for magnetically selecting the object to be processed obtained through the apparatus for preparing the object to be processed,
An apparatus for treating powdery or granular material, comprising: The said granular material is a soil, The processing apparatus of the granular material of Claim 11 characterized by the above-mentioned.