JP2021109138A - Adsorbent particle, base material particle, filling column, and rare earth element recovery method - Google Patents

Abstract

To provide an adsorbent particle that contains a carrier particle containing an organic polymer and has adsorbs a large amount of rare earth elements.SOLUTION: An adsorbent particle contains a carrier particle that contains an organic polymer containing a styrenic monomer-derived monomer unit, an amino group-containing polymer attached on the surface of the carrier particle, and a diglycolic acid residue bound to an amino group of the amino group-containing polymer. There is also provided a rare earth element recovery method using the adsorbent particle.SELECTED DRAWING: None

Description

The present invention relates to adsorbent particles, substrate particles, packed columns, and methods for recovering rare earth elements.

As an adsorbent that selectively adsorbs and desorbs rare earth elements, those in which diglycolic acid is introduced on the surface of various particles have been proposed (Patent Document 1, Non-Patent Documents 1 and 2).

Japanese Patent No. 6103611

Takeshi Ogata, Hydrometallurgy, 152 (2015) 178-182 Tomohiro Shinozaki, Ind.Eng.Chem. Res., 57 (2018) 11424-11430

Adsorbent particles containing carrier particles containing an organic polymer are also advantageous in terms of resistance to acid as compared with adsorbent particles containing inorganic particles such as silica particles as carrier particles. Therefore, one aspect of the present invention provides adsorbent particles containing carrier particles containing an organic polymer and having a large adsorption amount of rare earth elements.

で表される構成単位を含む。Ｒ^１がアルキレン基を示し、Ｒ^２が水素原子、アルキル基、又は、Ｒ^１と結合して環状構造を形成するアルキレン基を示す。 One aspect of the present invention is that the carrier particles containing an organic polymer containing a monomer unit derived from a styrene-based monomer, the amino group-containing polymer attached to the surface of the carrier particles, and the amino group of the amino group-containing polymer are bonded. Provided are adsorbent particles containing the same diglycolic acid residue. The amino group-containing polymer has the following formula (1) or (2):

Includes the building blocks represented by. R ¹ indicates an alkylene group, and R ² indicates a hydrogen atom, an alkyl group, or an alkylene group that combines with ^{R 1 to form a cyclic structure.}

Another aspect of the present invention relates to substrate particles comprising the carrier particles and the amino group-containing polymer attached to the surface of the carrier particles.

Yet another aspect of the present invention relates to a packed column comprising a column body and the adsorbent particles packed in the column body.

Yet another aspect of the present invention is that the adsorbent particles are brought into contact with a solution containing a rare earth element, whereby the rare earth element is adsorbed on the adsorbent particles, and the adsorbent particles are brought into contact with an acidic solution containing an acid. The present invention relates to a method for recovering a rare earth element, including desorbing the rare earth element from the adsorbent particles.

According to one aspect of the present invention, there is provided adsorbent particles containing carrier particles containing an organic polymer and having a large adsorption amount of rare earth elements.

It is a schematic diagram which shows one Embodiment of a filling column.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

The adsorbent particles according to one embodiment are a carrier particle containing an organic polymer, an amino group-containing polymer attached to the surface of the carrier particle, and a diglycolic acid residue covalently bonded to the amino group of the amino group-containing polymer. And include.

The diglycolic acid residue is a monovalent group represented by the following formula (10). The diglycolic acid residue interacts with the rare earth complex so that the adsorbent particles can adsorb the rare earth element.

The organic polymer constituting the carrier particles may be crosslinked. The proportion of the organic polymer in the carrier particles may be 50-100% by mass, 60-100% by mass, 70-100% by mass, 80-100% by mass, or 90-100% by mass.

The organic polymer constituting the carrier particles contains a styrene-based monomer as a monomer unit. The styrene-based monomer is styrene or a styrene derivative, and can be a crosslinkable monomer, a monofunctional monomer, or a combination thereof, which will be described later. The organic polymer may contain a monomer unit derived from a monomer other than the styrene-based monomer, but the ratio of the styrene-based monomer in the organic polymer is 20 mol% or more, or 20 mol% or more, based on the total amount of the monomer units constituting the organic polymer. It may be 35 mol% or more, 100 mol% or less, 85 mol% or less, or 70 mol% or less.

The crosslinkable styrene-based monomer may be at least one divinyl compound selected from divinylbenzene, divinylbiphenyl, divinylnaphthalene, and divinylphenanthrene. From the viewpoint of durability, acid resistance, and alkali resistance, the crosslinkable monomer may contain divinylbenzene. The proportion of the monomer units derived from the crosslinkable styrene-based monomer in the organic polymer is 1 to 80 mol%, 1 to 60 mol%, or 1 to 40 mol% with respect to the total amount of the monomer units constituting the organic polymer. It may be there.

Examples of monofunctional styrene-based monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 2 , 4-Dimethyl styrene, pn-butyl styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, p- Examples thereof include n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene. These may be used alone or in combination of two or more. From the viewpoint of acid resistance and alkali resistance, the monofunctional monomer may be styrene.

The organic polymer constituting the carrier particles may further contain a monomer having a reactive group that reacts with the amino group-containing polymer as a monomer unit, and a crosslinkable styrene-based monomer and a monomer having a reactive group as a monomer unit. It may be a copolymer containing. The monomer having a reactive group may be a styrene-based monomer or a monomer other than the styrene-based monomer. The reactive group may be, for example, an epoxy group, a chloro group or a combination thereof. Examples of monomers having an epoxy group include glycidyl methacrylate. Examples of monomers having a chloro group include 4-chloromethylstyrene. The proportion of the monomer unit derived from the monomer having a reactive group in the organic polymer may be 15 mol% or more, or 30 mol% or more, or 80 mol% or more, based on the total amount of the monomer units constituting the organic polymer. It may be less than or equal to 65 mol% or less.

The average particle size of the carrier particles may be 100 to 1000 μm or 200 to 1000 μm. As the average particle size of the carrier particles decreases, the pressure of the packed column packed with the adsorbent particles may increase. Here, the average particle size of the carrier particles can be determined by the following measuring method.
1) The particles are dispersed in water (including a dispersant such as a surfactant) to prepare a dispersion liquid containing 1% by mass of the particles.
2) Using a flow-type particle image analyzer, measure the average particle size from images of about 10,000 particles in the dispersion.

The carrier particles may be porous polymer particles. In the case of porous polymer particles, the surface inside the porous is also included in the "surface of the carrier particles". When the carrier particles are porous polymer particles, their specific surface area may be 50 m ² / g or more, or 1000 m ² / g or less. The larger the specific surface area, the larger the amount of substance adsorbed tends to be. The specific surface area here means the BET specific surface area due to the adsorption of nitrogen gas.

An amino group-containing polymer is a polymer containing a structural unit having an amino group. The structural unit having an amino group can be a monomer unit derived from a monomer having an amino group. The proportion of the monomer units derived from the monomer having an amino group is 60 to 100 mol%, 70 to 100 mol%, 80 to 100 mol%, 90 to 100 mol with respect to the amount of all the monomer units in the amino group-containing polymer. % Or 95-100 mol%. The amino group-containing polymer may be a homopolymer of a monomer having an amino group. The structural unit having an amino group is represented by the following formula (1) or (2).

In formula (1), R ¹ represents an alkylene group and R ² represents a hydrogen atom or an alkyl group. R ² may be an alkylene group that combines with R ^{1 to form a cyclic structure.} R ¹ may be an alkylene group having 1 to 3 carbon atoms or a methylene group. R ² may be an alkyl group having 1 to 3 carbon atoms. The ^{cyclic structure formed by combining R 2} with R ¹ may be a 5- to 8-membered ring. When R ¹ is a methylene group and R ² is a hydrogen atom, the structural unit represented by the formula (1) is a monomer unit derived from allylamine. The structural unit represented by the formula (2) is usually a monomer unit derived from diallylamine.

The structural unit represented by the formula (1) or (2) has a primary or secondary amino group. Due to this amino group reaction, at least a part of the amino group-containing polymer attached to the surface of the carrier particles is covalently bonded to diglucol acid. The structural unit having a diglycolic acid residue bonded to an amino group is represented by the following formula (1G) or (2G). ^{R 1} and ^{R 2} in the formula (1G) has the same meaning as ^{R 1} and ^{R 2} in the formula (1).

At least a part of the amino group-containing polymer attached to the surface of the carrier particles may be covalently bonded to the organic polymer constituting the carrier particles by the reaction of the amino group. The structural unit bonded to the organic polymer is represented by the following formula (1P) or (2P). ^{R 1} and ^{R 2} in the formula (1P) has the same meaning as ^{R 1} and ^{R 2} in the formula (1). Z in the formulas (1P) and (2P) represents the organic polymer constituting the carrier particles. The amino group-containing polymer attached to the surface of the carrier particles contains a structural unit represented by the formula (1), a structural unit represented by the formula (1G), and a structural unit represented by the formula (1P). It may also include a structural unit represented by the formula (2), a structural unit represented by the formula (2G), and a structural unit represented by the formula (2P).

For example, when the organic polymer constituting the carrier particles is a copolymer containing glycidyl methacrylate as a monomer unit, the organic polymer and the amino group-containing polymer are represented by the following formula (1P-1) or (2P-1). A cross-linked structure can be formed.

The weight average molecular weight of the amino group-containing polymer may be 200 or more, or 250 or more. The weight average molecular weight of the amino group-containing polymer may be 100,000 or less, 70,000 or less, 10,000 or less, or 7,000 or less. The weight average molecular weight here may be a standard polystyrene-equivalent value measured by gel permeation chromatography.

The ratio of the amount of the amino group-containing polymer to the mass of the carrier particles may be, for example, 5 to 50% by weight, or 10 to 40% by weight. The amount of amino groups in the adsorbent particles may be 0.1 to 100 mmol or 0.5 to 20 mmol per 1 g of the adsorbent particles.

The amount of amino groups in the adsorbent particles or the substrate particles described later can be determined by a method of measuring the amount of sulfuric acid consumed by the reaction with the amino groups by titration using sodium hydroxide. The method for measuring the amount of amino groups in the substrate particles includes the following operations.
1) Methanol is added to the base particle (A) g, and the obtained dispersion is heated at 75 ° C. for 30 minutes.
2) From the dispersion liquid, the substrate particles are collected on the filter by suction filtration. Methanol is replaced with pure water by adding pure water to the substrate particles on the filter while continuing suction, and then the substrate particles are conditioned with a small amount of 0.1 M aqueous sodium hydroxide solution. Then, the substrate particles are washed with pure water until the filtrate becomes neutral.
3) Transfer the washed substrate particles to a glass container using a small amount of pure water. Adjust so that the total amount of pure water in the container is (B) g.
4) Add (C) g of 0.05 M sulfuric acid to the dispersion in the container, and then stir the dispersion in the container at room temperature for 30 minutes at 150 rpm.
5) Take (D) g of the supernatant of the dispersion liquid and add pure water to it to adjust the liquid volume.
6) The supernatant after dilution is titrated with a 0.01 M aqueous sodium hydroxide solution, and the amount (E) mL of the aqueous sodium hydroxide solution required for neutralization is recorded.
7) The amount of amino groups is calculated by the following formula.
Amino group amount (mmol / g) = [{0.1 × C × D / (B + C) -0.01 × E} × (B + C) / D] / A

As the adsorbent particles, for example, base material particles having no diglycolic acid residue containing the carrier particles and the amino group-containing polymer attached to the surface of the carrier particles are prepared, and diglycolic acid is added to the amino group-containing polymer. Alternatively, it can be produced by a method including binding the anhydride thereof and thereby forming adsorbent particles. Diglycolic acid or an acid anhydride thereof can be bonded to the amino group of the amino group-containing polymer.

The base particles are produced by adhering an amino group-containing polymer to the surface of the carrier particles. An example of a method for preparing base material particles when the carrier particles contain an organic polymer having a reactive group is in a reaction solution containing a monomer component containing a monomer having a reactive group, a porosifying agent, and an aqueous medium. It includes producing carrier particles which are porous particles by suspension polymerization in the above, and binding the amino group-containing polymer to the organic polymer by the reaction of the reactive group and the amino group-containing polymer.

The porosifying agent used to form the porous particles is a component that promotes phase separation of the particles during polymerization, thereby forming porous polymer particles. An example of a porosifying agent is an organic solvent. Examples of organic solvents that can be used as the porosifying agent include aliphatic or aromatic hydrocarbons, esters, ketones, ethers, and alcohols. The porosifying agent is at least selected from the group consisting of, for example, toluene, xylene, cyclohexane, octane, butyl acetate, dibutyl phthalate, methyl ethyl ketone, dibutyl ether, 1-hexanol, 2-octanol, decanol, lauryl alcohol, and cyclohexanol. One type can be included.

The amount of the porosifying agent may be 0 to 300% by mass with respect to the total amount of the monomer components. The porosity of the porous polymer particles can be controlled by the amount of the porosity agent. The size and shape of the pores of the porous polymer particles can be controlled by the type of the porosifying agent.

The aqueous medium may contain water. This water may function as a porosifying agent. For example, when an oil-soluble surfactant is added to the reaction solution, particles containing the monomer and the oil-soluble surfactant are formed, and the particles can absorb water to promote phase separation in the particles. By removing one phase from the phase-separated particles, the particles are made porous.

The aqueous medium contains water or a mixed solvent of water and a water-soluble solvent (for example, a lower alcohol). The aqueous medium may contain a surfactant. The surfactant may be an anionic, cationic, nonionic or zwitterionic surfactant.

The reaction solution for suspension polymerization may contain a polymerization initiator. Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, benzoyl orthochloro peroxide, benzoyl orthomethoxy peroxide, 3,5,5-trimethylhexanoyl peroxide, and tert-butylperoxy-2-ethylhexano. Organic peroxides such as ate, di-tert-butyl peroxide; 2,2'-azobisisobutyronitrile, 1,1'-azobiscyclohexanecarbonitrile, 2,2'-azobis (2,4-azobis) Examples thereof include azo compounds such as dimethylvaleronitrile). The amount of the polymerization initiator may be 0.1 to 7.0 parts by mass with respect to 100 parts by mass of the monomer component.

The reaction solution may contain a dispersion stabilizer in order to improve the dispersion stability of the particles containing the monomer component. Examples of the dispersion stabilizer include polyvinyl alcohol, polycarboxylic acid, celluloses (hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, etc.), and polyvinylpyrrolidone. These may be used in combination with an inorganic water-soluble polymer compound such as sodium tripolyphosphate. The dispersion stabilizer may be polyvinyl alcohol or polyvinylpyrrolidone. The amount of the dispersion stabilizer may be 1 to 10 parts by mass with respect to 100 parts by mass of the monomer.

The reaction solution for suspension polymerization may contain a water-soluble polymerization inhibitor such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble B vitamins, citric acid, and polyphenols.

The polymerization temperature for suspension polymerization can be appropriately selected depending on the type of the monomer and the polymerization initiator. The polymerization temperature may be 25 to 110 ° C. or 50 to 100 ° C.

When the hydrophilic organic compound is an amino group-containing polymer, the generated porous particles (carrier particles) are washed and dried as necessary, and then the amino group of the amino group-containing polymer is reacted with the reactive group of the organic polymer. .. This reaction can be carried out, for example, in a reaction solution containing carrier particles, an amino group-containing polymer, and a solvent while heating, if necessary. The solvent is not particularly limited, but may be, for example, water.

After washing and drying the base particles as necessary, diglycolic acid or an anhydride thereof is bonded to the amino groups of the amino group-containing polymer attached to the carrier particles. This reaction can be carried out, for example, in a reaction solution containing base particles, diglycolic acid or an anhydride thereof, and a solvent while heating, if necessary. The solvent is not particularly limited, but may be, for example, tetrahydrofuran. This reaction forms adsorbent particles into which diglycolic acid residues have been introduced. The formed adsorbent particles are washed and dried if necessary.

Substrate particles containing the carrier particles and the amino group-containing polymer attached to the surface of the carrier particles may be used to obtain adsorbent particles or separator particles into which a ligand other than the diglycolic acid residue has been introduced. The average particle size of the substrate particles is usually substantially the same as the average particle size of the adsorbent particles.

A method including contacting a solution containing a rare earth element with an adsorbent particle to adsorb the rare earth element to the adsorbent particle, and desorbing the rare earth element from the adsorbent particle in an acidic solution containing an acid. Therefore, rare earth elements can be efficiently recovered.

The temperature of the solution for adsorption and the acidic solution for desorption is not particularly limited, but may be, for example, 15 to 35 ° C. The contact time between the solution for adsorption and the adsorbent particles may be, for example, 20 seconds or more, 40 seconds or more, or 48 hours or less. The contact time between the acidic solution for desorption and the adsorbent particles may be, for example, 5 seconds or more, 10 seconds or more, or 6 hours or less.

The recovery method using the adsorbent particles according to the present embodiment enables efficient recovery of the rare earth element based on the large amount of adsorption by the adsorbent particles and the efficient desorption of the adsorbed rare earth element. Further, since the adsorbent particles according to the present embodiment have high resistance to acid as compared with the adsorbent containing silica particles as carrier particles, they are also advantageous in that they are less deteriorated when used repeatedly.

The pH of the solution when the rare earth element is adsorbed on the adsorbent particles may be about 1.0 to 2.0. Acidity The acidity of the acidic solution for desorbing the rare earth element is adjusted to such an intensity that the rare earth element is appropriately desorbed. For example, the acid concentration of the acidic solution may be 2 or less, 1 or less, or 0.5 or less. The adsorbent particles according to the present embodiment can desorb rare earth elements with high efficiency even when a relatively weak acidic acidic solution is used. The use of a weakly acidic acidic solution is beneficial not only in suppressing deterioration of the adsorbent but also in reducing the environmental load. The acidic solution may be, for example, hydrochloric acid.

The rare earth element to be recovered may be any of scandium, yttrium, and lanthanoid, and may be lanthanoid such as dysprosium and neodymium. The solution containing the recovered rare earth element may be an aqueous solution. Rare earth elements in solution are usually dissolved in a solvent (eg water) as cations.

Adsorbent particles may be used as the column packing material. FIG. 1 is a schematic view showing an embodiment of a filling column. The filling column 10 shown in FIG. 1 includes a column main body portion 11 (column tube), a connecting portion 12, and a column packing material 13 containing adsorbent particles according to the above-described embodiment. The connection portions 12 are arranged at both ends of the column body portion 11 in order to connect the column body portion 11 to the column chromatography apparatus. The column packing material 13 is filled in the tubular column main body 11. The material of the column body 11 and the connecting portion 12 is not particularly limited, and may be stainless steel or a resin such as polyetheretherketone (PEEK).

The column packing material 13 containing the adsorbent particles is usually filled in the column body 11 together with the solvent. The solvent is not particularly limited as long as it is a solvent in which the adsorbent particles are dispersed, but may be, for example, water.

When recovering a rare earth element using a packed column, for example, a solution containing the rare earth element is passed through the packed column, and then an acidic solution is passed through the packed column.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

1. 1. Preparation of Adsorbent Particles Example 1
Substrate particles Porous polymer particles made of divinylbenzene-glycidyl methacrylate copolymer were prepared as carrier particles. The porous polymer particles were added to methanol, and the suspension was shaken and stirred to wet the porous polymer particles with methanol. Then, the suspension was filtered with pure water while maintaining a wet state to replace methanol with pure water. Subsequently, the solvent of the suspension was replaced with an aqueous solution (concentration: 20% by mass) of polyallylamine (weight average molecular weight: 5000), which is an amine-containing polymer, from pure water in the same manner. The suspension was heated at 80 ° C. for 8 hours to allow the reaction of the epoxy groups of the porous polymer particles with polyallylamine. The porous polymer particles taken out by filtration were thoroughly washed with ethanol and water, and then dried at 80 ° C. for 15 hours to obtain base particles into which polyallylamine was introduced. The average particle size of the obtained base particles was 400 μm, and the amount of amino groups per 1 g of the base particles was 3.2 mmol.

Adsorbent particles 1.2 g of base particles and 5.6 g of diglycolic acid anhydride were reacted in tetrahydrofuran at 50 ° C. for 8 hours. The particles taken out by filtration were thoroughly washed with ethanol and water, and then dried at 80 ° C. for 15 hours to obtain adsorbent particles into which diglycolic acid residues were introduced.

Example 2
The adsorbent particles into which the diglycolic acid residue was introduced were obtained by the same operation as in Example 1 except that the polyallylamine was changed to one having a weight average molecular weight of 15,000 and an aqueous solution thereof (concentration: 15% by mass) was used. rice field. The average particle size of the base particles was 400 μm, and the amount of amino groups per 1 g of the base particles was 3.6 mmol.

Comparative Example 1
Porous polymer particles made of the same divinylbenzene-glycidyl methacrylate copolymer as in Example 1 were prepared as carrier particles. The porous polymer particles were added to methanol, and the suspension was shaken and stirred to wet the porous polymer particles with methanol. Then, the suspension was filtered with pure water while maintaining a wet state to replace methanol with pure water. Subsequently, the solvent of the suspension was replaced with ethylenediamine from pure water in the same manner. By heating the suspension at 80 ° C. for 8 hours, the reaction between the epoxy group of the porous polymer particles and ethylenediamine was allowed to proceed. The porous polymer particles taken out by filtration were thoroughly washed with ethanol and water, and then dried at 80 ° C. for 15 hours to obtain base particles into which ethylenediamine had been introduced. The average particle size of the base particles was 400 μm, and the amount of amino groups per 1 g of the base particles was 2.4 mmol. The adsorbent particles into which the diglycolic acid residue was introduced were obtained by the same operation as in Example 1 except that the obtained base material particles were used.

2. Adsorption test 20 mL of an aqueous solution for an adsorption test containing dysprosium (Dy) at a concentration of 160 ppm and adjusted to pH 1.5 was prepared. 50 mg of adsorbent particles of each example was added to this aqueous solution. The suspension containing the adsorbent particles was shaken while maintaining at 25 ° C. After adsorbing dysprosium ions on the adsorbent particles by shaking for 10 minutes or 24 hours, the concentration of dysprosium ions in the aqueous solution was measured by an ICP emission spectrometer of the aqueous solution collected from the suspension. The amount of dysprosium ion adsorbed per 1 g of adsorbent particles (μmol / g) was calculated from the difference in ion concentration before and after adsorption.
Adsorbent particles of Comparative Example 1 were operated in the same manner as above except that 50 mg of adsorbent particles were added to 5 mL of an aqueous solution for adsorption test in which dysprosium (Dy) was contained at a concentration of 160 ppm and the pH was adjusted to 2.0. The amount of dysprosium ion adsorbed per 1 g (μmol / g) was determined.

As shown in Table 1, it was confirmed that the adsorbent particles of the examples adsorb rare earth elements with a sufficiently large adsorption amount. It can be said that the amount adsorbed by the adsorbent particles of the examples is clearly larger than the amount adsorbed by the adsorbent particles of the comparative example, even considering that the test conditions are slightly different.

10 ... Filling column, 11 ... Column body, 12 ... Connection, 13 ... Column packing material.

Claims (10)

Carrier particles containing an organic polymer containing a monomer unit derived from a styrene-based monomer, and
The following formula (1) or (2): attached to the surface of the carrier particles:

An amino group-containing polymer containing a structural unit represented by, where R ¹ represents an alkylene group and R ² represents a hydrogen atom, an alkyl group, or an alkylene group which is bonded to ^{R 1 to form a cyclic structure.}
The diglycolic acid residue bonded to the amino group of the amino group-containing polymer and
Containing, adsorbent particles. The adsorbent particle according to claim 1, wherein the carrier particles are porous polymer particles. The adsorbent particle according to claim 1 or 2, wherein the amount of amino groups in the adsorbent particle is 0.1 to 100 mmol per 1 g of the adsorbent particle. The adsorbent particle according to any one of claims 1 to 3, which is used for recovering a rare earth element. Carrier particles containing an organic polymer containing a monomer unit derived from a styrene-based monomer, and
The following formula (1) or (2): attached to the surface of the carrier particles:

An amino group-containing polymer containing a structural unit represented by, where R ¹ represents an alkylene group and R ² represents a hydrogen atom, an alkyl group, or an alkylene group which is bonded to ^{R 1 to form a cyclic structure.}
With base particles. The base material particles according to claim 5, wherein the carrier particles are porous polymer particles. The base particle according to claim 5 or 6, wherein the amount of the amino group in the base particle is 0.1 to 100 mmol per 1 g of the base particle. The base material particles according to any one of claims 5 to 7, which are used for forming adsorbent particles containing a diglycolic acid residue bonded to an amino group of the amino group-containing polymer. A packed column comprising a column main body portion and the adsorbent particles according to any one of claims 1 to 4 filled in the column main body portion. The adsorbent particles according to any one of claims 1 to 3 are brought into contact with a solution containing a rare earth element, whereby the rare earth element is adsorbed on the adsorbent particles.
Desorption of the rare earth element from the adsorbent particles by contact with an acidic solution containing an acid.
A method of recovering rare earth elements, including.

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