Pyrone-based chelate resin and preparation method and impurity removal method thereof

Abstract

The invention relates to pyrone-based chelate resin as well as a preparation method and an impurity removal method thereof. A main chain framework of the pyrone-based chelate resin is styryl adsorption resin, and at least one pyrone functional group is grafted to a side chain of the styryl adsorption resin. Wherein the oxygen-rich structure of a pyrone functional group and nitrogen atoms on a main chain skeleton can generate strong coordination with aluminum ions, and a stable six-membered ring chelate is formed through a chelation reaction, and shows excellent selective aluminum removal performance. Meanwhile, the pyrone functional group has acid-base property and can be subjected to ion exchange reaction or physical adsorption with organic matters, so that TOC in the water environment is effectively removed. Therefore, by adopting the pyrone-based chelating resin provided by the invention, the aluminum ions and TOC in the rare earth feed liquid can be efficiently removed through the cooperation of the oxygen-rich coordination effect and the selective ion exchange capacity, and the loss rate of the rare earth ions is obviously reduced.

Description

Technical Field

[0001] The present application relates to the technical field of rare earth products, and in particular to a pyrone-based chelating resin and a preparation method and an impurity removal method thereof. Background Art

[0002] Rare Earth Elements (REEs), known as industrial gold, have unique optical, magnetic and catalytic properties and play a vital role in display, hybrid vehicles, superconductors, nuclear energy applications, etc. The value of rare earth products is usually affected by the purity of the products, so it is necessary to remove impurities from the rare earth liquid during the preparation process.

[0003] Rare earth liquid refers to a solution or suspension containing rare earth elements. Rare earth liquid usually contains impurities such as aluminum and total organic carbon (TOC), which affect the purity and performance of rare earth products. However, when removing aluminum and TOC from rare earth liquid, traditional methods have the problems of high rare earth loss rate and low impurity removal rate. Summary of the invention

[0004] Based on this, it is necessary to provide a pyrone-based chelating resin and a preparation method and an impurity removal method thereof to solve the problems of high rare earth loss rate and low impurity removal rate when removing aluminum and TOC from rare earth liquid by traditional methods.

[0005] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0006] In a first aspect of the present application, a pyrone-based chelate resin is provided. The pyrone-based chelate resin has a structure as shown in the general formula (I):

[0007] (I); (Ⅱ-1); (Ⅱ-2);

[0008] Wherein, n is selected from a positive integer;

[0009] R 1 and R 2 Each is independently selected from H, a structure as shown in the general formula (II-1) and a structure as shown in the general formula (II-2), and R 1 and R 2 Not selected from H at the same time;

[0010] R 3 and R 4Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

[0011] In some embodiments, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, C 1 ~C 3 Alkyl, hydroxy substituted C 1 ~C 3 Alkyl and C 1 ~C 3 One of the alkoxy groups.

[0012] In some embodiments, R 3 and R 4 Each occurrence is independently selected from one of H, hydroxy, carboxyl, methyl, hydroxymethyl and methoxy.

[0013] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for TOC is ≥ 1800 mg / g.

[0014] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for aluminum ions is ≥20 mg / g.

[0015] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for rare earth ions is ≤0.02 mg / g.

[0016] In a second aspect of the present application, a method for preparing a pyrone-based chelating resin is provided, comprising the following steps:

[0017] subjecting an amino resin, a pyrone compound and an aldehyde compound to a Mannich reaction to obtain the pyrone-based chelating resin;

[0018] The amino resin has a structure as shown in the general formula (IV), the pyrone compound has a structure as shown in the general formula (V-1) or the general formula (V-2), and the aldehyde compound includes formaldehyde or paraformaldehyde;

[0019] (IV); (V-1); (V-1);

[0020] Wherein, n is a positive integer;

[0021] R 3 and R 4Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

[0022] In some embodiments, the pyrone compound includes at least one of 5-hydroxy-2-hydroxymethyl-4-pyrone, 3-hydroxy-2-methyl-4-pyrone, 5-methoxy-2-hydroxymethyl-4-pyrone, 4-methoxy-6-methyl-2-pyrone, and 2-pyrone-5-carboxylic acid.

[0023] In some embodiments, the amino resin, the pyrone compound and the aldehyde compound are subjected to a Mannich reaction, comprising the following steps: mixing the amino resin, the pyrone compound, the aldehyde compound and the third solvent, heating to 60° C. to 100° C., adding a catalyst, and reflux reacting for 6 h to 12 h to obtain the pyrone-based chelating resin.

[0024] In some embodiments, the mass ratio of the amino resin, the pyrone compound and the aldehyde compound is 1:(1-3):(0.15-0.45).

[0025] In some embodiments, the mass ratio of the amino resin, the catalyst and the third solvent is 1:(0.1-0.3):(4-6).

[0026] In some embodiments, the catalyst includes at least one of an inorganic acid and an inorganic base.

[0027] In some embodiments, the third solvent comprises a protic solvent.

[0028] In some embodiments, the preparation method of the amino resin comprises Gabriel synthesis method.

[0029] In a third aspect of the present application, a method for removing impurities from a rare earth liquid is provided, comprising the following steps:

[0030] The pyrone-based chelating resin or the pyrone-based chelating resin prepared by the preparation method of the pyrone-based chelating resin is used to perform adsorption treatment on rare earth feed solution to remove aluminum ions and TOC in the rare earth feed solution.

[0031] In some embodiments, the method for removing impurities from the rare earth liquid comprises the following steps:

[0032] The pyrone-based chelating resin is loaded into a chromatography column and pre-treated with water to obtain a blank column;

[0033] Allowing the rare earth material liquid to flow through the blank column for adsorption treatment to obtain an adsorption liquid and an adsorption column;

[0034] Desorbing the adsorption column by using an acid solution to obtain a desorption liquid and a desorption column;

[0035] The desorption column is regenerated by using water to obtain the blank column.

[0036] In some embodiments, the aspect ratio of the chromatography column is 8-20.

[0037] In some embodiments, in the adsorption treatment, the dosage of the rare earth solution is 1.5BV~9BV, and the flow rate of the rare earth solution is 1BV / h~5BV / h.

[0038] In some embodiments, in the desorption process, the amount of the acid solution is 2BV~6BV, and the flow rate of the acid solution is 1BV / h~5BV / h.

[0039] In some embodiments, the mass fraction of the acid in the acid solution is 5% to 15%.

[0040] In some embodiments, the acid in the acid solution includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0041] In some embodiments, in the pretreatment and / or the regeneration treatment, the amount of water used is 2BV~5BV, and the flow rate of the water is 1BV / h~5BV / h.

[0042] This application has at least the following beneficial effects:

[0043] The main chain skeleton of the pyrone-based chelating resin provided by the present application is a styrene-based adsorption resin, and its side chain is grafted with at least one pyrone functional group. Among them, the polyoxygen structure of the pyrone functional group and the nitrogen atoms on the main chain skeleton can produce a strong coordination effect with aluminum ions, and form a stable six-membered ring chelate through a chelation reaction, and this coordination effect is stronger than the coordination effect between the pyrone functional group and the rare earth element, thereby showing excellent selective aluminum removal performance. At the same time, the pyrone functional group has acidity and alkalinity, and can undergo ion exchange reaction or physical adsorption with organic matter, thereby effectively removing TOC in the water environment. Therefore, by using the pyrone-based chelating resin provided by the present application, aluminum ions and TOC in the rare earth feed liquid can be efficiently removed through the synergistic cooperation of the polyoxygen coordination effect and the selective ion exchange capacity, and the loss rate of rare earth ions is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0045] Figure 1 Schematic diagram of a process for preparing a pyrone-based chelating resin in one embodiment;

[0046] Figure 2 Schematic diagram of a process for removing impurities from a rare earth liquid in one embodiment;

[0047] Figure 3 The synthetic route of the amino resin of Example 1 is shown in FIG.

[0048] Figure 4 The synthetic route diagram of the pyrone-based chelating resin of Example 1;

[0049] Figure 5 It is the infrared spectrogram of the pyrone-based chelating resin of Example 1;

[0050] Figure 6 The figure is the adsorption result of the pyrone-based chelating resin of Example 1 after 5 cycles. DETAILED DESCRIPTION

[0051] In order to facilitate the understanding of the present application, the present application is further described in detail below in conjunction with specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0053] In the present application, the meaning of "and / or" includes any and all combinations of one or more related listed items. "At least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layer" means at least two layers, such as two layers, three layers, etc., unless otherwise clearly and specifically defined. In the description of the present application, "several" means at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0054] When a numerical range is disclosed in this application, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges included therein.

[0055] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0056] In this application, "above" or "below" includes the number itself. For example, "1 below" includes 1.

[0057] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0058] In the present application, room temperature refers to indoor temperature, normal temperature or general temperature. Generally speaking, the range of room temperature can be any one of the following temperature intervals: 23°C ± 2°C, 25°C ± 5°C or 20°C ± 5°C.

[0059] the term

[0060] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0061] In the present application, when a substituent with the same symbol appears multiple times, each substituent may be the same or different from each other. For example, when a general formula contains multiple R, R may be the same or different from each other.

[0062] "Substituted or unsubstituted" means that the defined group may be substituted or unsubstituted. When the defined group is substituted, it should be understood that the defined group may be substituted by one or more substituents acceptable in the art. Suitable substituents include but are not limited to: C 1 ~C 30Alkyl, cycloalkyl containing 3 to 20 ring atoms, heterocyclic group containing 3 to 20 ring atoms, aryl containing 6 to 20 ring atoms, heteroaryl containing 5 to 20 ring atoms, silanyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, haloformyl, formyl, amino, cyano, isocyano, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, nitro or halogen, and the above groups may also be further substituted by substituents acceptable in the art.

[0063] The "number of ring atoms" refers to the number of atoms constituting the ring itself of a structural compound (e.g., a monocyclic compound, a condensed ring compound, a cross-linked compound, a carbocyclic compound, a heterocyclic compound) in which atoms are bonded to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. The "number of ring atoms" described below is the same unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thienyl group is 5.

[0064] "Alkyl" refers to a saturated hydrocarbon containing primary (normal) carbon atoms, or secondary carbon atoms, or tertiary carbon atoms, or quaternary carbon atoms, or a combination thereof. Phrases containing this term, such as "C 1 ~C 9 "Alkyl" refers to an alkyl group containing 1 to 9 carbon atoms, each occurrence of which can be independently C 1 Alkyl, C 2 Alkyl, C 3 Alkyl, C 4 Alkyl, C 5 Alkyl, C 6 Alkyl, C 7 Alkyl, C 8 Alkyl or C 9 Suitable examples include, but are not limited to, methyl (Me, -CH 3 ), ethyl (Et, -CH 2 CH 3 ), 1-propyl (n-Pr, n-propyl, -CH 2 CH 2 CH 3 ), 2-propyl (i-Pr, i-propyl, -CH (CH 3 ) 2 ), 1-butyl (n-Bu, n-butyl, -CH 2 CH 2 CH 2 CH 3 ), 2-methyl-1-propyl (i-Bu, i-butyl, -CH 2 CH(CH 3 ) 2), 2-butyl (s-Bu, s-butyl, -CH (CH 3 )CH 2 CH 3 ), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH 3 ) 3 ), 1-pentyl (n-pentyl, -CH 2 CH 2 CH 2 CH 2 CH 3 ), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH 2 CH 3 ) 2 ), 2-methyl-2-butyl (-C(CH 3 ) 2 CH 2 CH 3 ), 3-methyl-2-butyl (-CH(CH 3 )CH(CH 3 ) 2 ), 3-methyl-1-butyl (-CH 2 CH 2 CH(CH 3 ) 2 ), 2-methyl-1-butyl (-CH 2 CH(CH 3 )CH 2 CH 3 )、1-hexyl (-CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 ), 2-hexyl (-CH(CH 3 )CH 2 CH 2 CH 2 CH 3 )、3-hexyl(-CH(CH 2 CH 3 )(CH 2 CH 2 CH 3 ))、2-methyl-2-pentyl (-C(CH 3 ) 2 CH 2 CH 2 CH 3 ), 3-methyl-2-pentyl (-CH(CH 3 )CH(CH 3 )CH2 CH 3 ), 4-methyl-2-pentyl (-CH(CH 3 )CH 2 CH(CH 3 ) 2 ), 3-methyl-3-pentyl (-C(CH 3 )(CH 2 CH 3 ) 2 ), 2-methyl-3-pentyl (-CH(CH 2 CH 3 )CH(CH 3 ) 2 )、2,3-dimethyl-2-butyl (-C(CH 3 ) 2 CH(CH 3 ) 2 )、3,3-dimethyl-2-butyl (-CH(CH 3 )C(CH 3 ) 3 and octyl (-(CH 2 ) 7 CH 3 ).

[0065] "Alkoxy" refers to a group having an -O-alkyl group, i.e., an alkyl group as defined above attached via an oxygen atom to a parent core structure. Phrases containing this term, such as "C 1 ~C 9 "Alkoxy" means that the alkyl part contains 1 to 9 carbon atoms, each occurrence can be independently C 1 Alkoxy, C 4 Alkoxy, C 5 Alkoxy, C 6 Alkoxy, C 7 Alkoxy, C 8 Alkoxy or C 9 Suitable examples include, but are not limited to, methoxy (—O—CH 3 or -OMe), ethoxy (-O-CH 2 CH 3 or -OEt) and tert-butyloxy (-OC(CH 3 ) 3 or -OtBu).

[0066] "Alkenyl" refers to a group containing at least one unsaturated site, i.e., a carbon-carbon sp 2 A hydrocarbon containing a positive, secondary, tertiary, or cyclic carbon atom with a double bond. Phrases containing this term, such as "C 2 ~C 9"Alkenyl" refers to an alkenyl group containing 2 to 9 carbon atoms, each occurrence of which can be independently C 2 Alkenyl, C 3 Alkenyl, C 4 Alkenyl, C 5 Alkenyl, C 6 Alkenyl, C 7 Alkenyl, C 8 Alkenyl or C 9 Suitable examples include, but are not limited to, vinyl (-CH=CH 2 ), allyl (-CH 2 CH=CH 2 ), cyclopentenyl (-C 5 H 7 ) and 5-hexenyl (-CH 2 CH 2 CH 2 CH 2 CH=CH 2 ).

[0067] "Alkynyl" refers to a hydrocarbon containing a normal, secondary, tertiary, or cyclic carbon atom having at least one site of unsaturation, i.e., a carbon-carbon sp triple bond. Phrases containing this term, such as "C 2 ~C 9 "Alkenyl" refers to an alkynyl group containing 2 to 9 carbon atoms, each occurrence of which can be independently C 2 Alkynyl, C 3 Alkynyl, C 4 Alkynyl, C 5 Alkynyl, C 6 Alkynyl, C 7 Alkynyl, C 8 Alkynyl or C 9 Suitable examples include, but are not limited to, ethynyl (-C≡CH) and propargyl (-CH 2 C≡CH).

[0068] "Aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing a hydrogen atom. It can be a monocyclic aromatic group, a condensed aromatic group, or a polycyclic aromatic group. For polycyclic rings, at least one is an aromatic ring system. For example, "C 5 ~C 20 "Aryl" refers to an aromatic group containing 5 to 20 carbon atoms, each occurrence of which can be independently C 5 Aryl, C 6 Aryl, C 10 Aryl, C 14 Aryl, C 18 Aryl or C 20Suitable examples include, but are not limited to, benzene, biphenyl, naphthalene, anthracene, phenanthrene, perylene, triphenylene, and derivatives thereof.

[0069] "Halogen" refers to F, Cl, Br or I.

[0070] "Hydroxyl" refers to -OH.

[0071] "Mercapto" refers to -SH.

[0072] "Carboxyl" refers to -COOH.

[0073] "Ester group" refers to a monovalent residue having the structural characteristics of the general formula -COOR, wherein R is selected from substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic group, etc. Suitable examples include, but are not limited to: methyl ester group (methyl ester group, -COOCH 3 ), ethyl ester (ethyl ester, -COOCH 2 CH 3 ).

[0074] "Amino" refers to a derivative of ammonia having the formula -N(X) 2 The structural features of , wherein each "X" is independently H, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclyl, etc.

[0075] "White balls" refer to styrene-divinylbenzene copolymers in styrene-based adsorption resins. The white balls are subjected to chloromethylation reaction to introduce -CH 2 Cl active group, this with -CH 2 The styrene-based adsorption resin with Cl-active groups is called "chlorine ball".

[0076] "Swelling" refers to the phenomenon that high molecular polymers, such as white balls, chlorine balls and amino resins, expand in volume after being immersed in solvents, which can make the molecular structure of the high molecular polymer loose.

[0077] Aluminum is the most common impurity element in rare earth liquid. The coexistence of aluminum and rare earth elements has the following problems: (1) It increases the amount of precipitant used in the subsequent separation and purification process; (2) It reduces the extraction capacity of the solvent and forms a stable complex with the extract, resulting in emulsification; (3) It affects the performance of rare earth products. For example, the presence of aluminum will reduce the saturation magnetization intensity and magnetic anisotropy field of neodymium iron boron (NdFeB) magnets. Therefore, in the industrial production process, it is particularly important to separate aluminum ions from rare earth resources.

[0078] At present, the main methods for removing aluminum from rare earth liquid are selective precipitation and solvent extraction. Among them, the selective precipitation method has a mature process, simple operation, and a large processing volume, but it requires a large amount of precipitants (such as oxalic acid, ammonium bicarbonate, ammonia water, etc.), and has the disadvantages of high rare earth element loss and low aluminum element removal rate. The solvent extraction method has the advantages of high separation efficiency, good continuous productivity, and large production capacity, but the extraction process also means the use of a large amount of organic solvents. On the one hand, it leads to an increase in the TOC content of the rare earth liquid, affecting the subsequent rare earth element extraction. On the other hand, the volatility and corrosiveness of organic solvents have a significant negative impact on equipment, environment, and personnel.

[0079] Total Organic Carbon (TOC) refers to the total carbon content of all organic matter in water and is one of the important parameters for evaluating water quality. TOC can come from natural processes (such as plant decay, etc.) or from human activities (such as industrial wastewater discharge, etc.). Too high TOC content may pollute the water body, affect the taste and odor of the water, and may even produce harmful disinfection by-products. Therefore, it is very necessary to remove TOC from water environments such as rare earth liquid.

[0080] At present, the main methods for removing TOC include advanced oxidation technology, membrane separation technology and biological treatment technology. Among them, advanced oxidation technology includes ozone oxidation, ultraviolet oxidation and Fenton reaction, all of which remove TOC by oxidizing organic matter into carbon dioxide and water. It has a wide range of applications, but requires expensive equipment and operating costs, and the reaction is energy-intensive and the conditions are harsh. The membrane of membrane separation technology is easily contaminated and needs to be replaced frequently, resulting in excessively high costs. The external pressure of the membrane also increases energy consumption and costs. The operating cost of biological treatment technology is relatively low, and it mainly relies on the natural degradation of microorganisms, but the biological treatment process takes a long time, is not suitable for occasions that require rapid treatment, and the microorganisms are greatly affected by environmental factors.

[0081] Therefore, when traditional methods are used to remove aluminum and TOC from rare earth liquid, there are often problems such as high rare earth element loss rate, low aluminum removal rate and low TOC removal rate.

[0082] Based on this, in a first aspect, the present application provides a pyrone-based chelating resin.

[0083] In some embodiments, the pyrone-based chelating resin has a structure as shown in the general formula (I):

[0084] (I); (Ⅱ-1); (Ⅱ-2);

[0085] Wherein, n is selected from a positive integer;

[0086] R 1 and R 2 Each is independently selected from H, a structure as shown in the general formula (II-1) and a structure as shown in the general formula (II-2), and R 1 and R 2 Not selected from H at the same time;

[0087] R 3 and R 4 Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

[0088] In this application, the chemical formula of pyrone is C 5 H 4 O 2 , is a class of six-membered oxygen-containing heterocyclic compounds. According to the position of the double bond and carbon group in the ring, it can be divided into two isomers: α-pyrone and γ-pyrone. The structures are shown in general formula (III-1) or general formula (III-2):

[0089] (III-1); (III-2);

[0090] The ring of the pyrone group has two double bonds and two oxygen atoms (one carbonyl group and one ether bond), which can participate in various chemical reactions such as nucleophilic addition reactions, acid-base reactions and redox reactions. It has antibacterial, antiviral, anti-inflammatory, anti-tumor and antioxidant effects, and is widely used in the fields of medicine, fragrances, dyes, pesticides and materials science.

[0091] The main chain skeleton of the pyrone-based chelating resin provided by the present application is a styrene-based adsorption resin, and its side chain is grafted with at least one pyrone functional group. Among them, the polyoxygen structure of the pyrone functional group and the nitrogen atoms on the main chain skeleton can produce a strong coordination effect with aluminum ions, and form a stable six-membered ring chelate through a chelation reaction, and this coordination effect is stronger than the coordination effect between the pyrone functional group and the rare earth element, thereby showing excellent selective aluminum removal performance. At the same time, the pyrone functional group has acidity and alkalinity, and can undergo ion exchange reaction or physical adsorption with organic matter, thereby effectively removing TOC in the water environment. Therefore, by using the pyrone-based chelating resin provided by the present application, aluminum ions and TOC in the rare earth feed liquid can be efficiently removed through the synergistic cooperation of the polyoxygen coordination effect and the selective ion exchange capacity, and the loss rate of rare earth ions is significantly reduced.

[0092] In the present application, in the structure shown in general formula (I), n is selected from a positive integer. In some embodiments, n is selected from a positive integer between 1 and 1000, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 200, 300, 400, 500 or 1000.

[0093] In the present application, the structure represented by the general formula (II-1) represents an α-pyrone functional group, and the structure represented by the general formula (II-2) represents a γ-pyrone functional group. 1 and R 2 are each independently selected from one of H, α-pyrone functional group and γ-pyrone functional group, and R 1 and R 2 are not simultaneously selected from H. Suitable combinations may be: H and α-pyrone functional group; H and γ-pyrone functional group; α-pyrone functional group and α-pyrone functional group; α-pyrone functional group and γ-pyrone functional group; γ-pyrone functional group and γ-pyrone functional group.

[0094] In some embodiments, R 1 and / or R 2 Selected from the structure shown in the general formula (II-2). The γ-pyrone functional group can take a proton in water and show strong alkalinity. At the same time, the oxygen atom on its ring contains a lone pair of electrons, which can be conjugated with the double bond, and has high structural stability. When forming salts, the protons will combine with the carbonyl oxygen atoms to form a closed aromatic conjugated system, which enhances the stability of the salt products. Therefore, the side chain graft of the pyrone-based chelating resin has at least one γ-pyrone functional group, which has stronger coordination ability for aluminum ions and ion exchange ability for TOC, further improving the removal rate of aluminum ions and TOC.

[0095] In this application, R 3 and R 4 Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl. Further, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, ester, sulfhydryl, amino, substituted or unsubstituted C 1 ~C 6 Alkyl, substituted or unsubstituted C 1 ~C 6 Alkoxy, substituted or unsubstituted C 1 ~C 6 Alkenyl, substituted or unsubstituted C 1 ~C6 Alkynyl and substituted or unsubstituted C 6 ~C 12 Furthermore, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, C 1 ~C 6 Alkyl, hydroxy substituted C 1 ~C 6 Alkyl and C 1 ~C 6 One of the alkoxy groups.

[0096] In some embodiments, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, C 1 ~C 3 Alkyl, hydroxy substituted C 1 ~C 3 Alkyl and C 1 ~C 3 One of the alkoxy groups.

[0097] Understandably, “C 1 ~C 3 The "alkyl" may be C 1 Alkyl, C 2 Alkyl or C 3 Alkyl. "Hydroxy-substituted C 1 ~C 3 "Alkyl" means C 1 ~C 3 At least one hydrogen atom on the alkyl group is replaced by a hydroxyl group. 1 ~C 3 The "alkoxy" may be C 1 Alkoxy, C 2 Alkoxy or C 3 Alkoxy.

[0098] In some embodiments, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl (-OH), carboxyl (-COOH), methyl (-CH 3 ), hydroxymethyl (-CH 2 OH) and methoxy (-OCH 3 )

[0099] In some embodiments, R 1 and / or R 2 At least one selected from the structure represented by the general formula (II-3) and the structure represented by the general formula (II-4):

[0100] (II-3); (Ⅱ-4).

[0101] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for TOC is ≥1800 mg / g, including but not limited to 1800 mg / g, 1900 mg / g, 2000 mg / g, 2100 mg / g, 2200 mg / g, 2300 mg / g, 2400 mg / g, 2500 mg / g, 2600 mg / g, 2700 mg / g, 2800 mg / g, 2900 mg / g or 3000 mg / g. Further, the adsorption capacity of the pyrone-based chelating resin for TOC is 1800 mg / g to 3000 mg / g.

[0102] In some embodiments, under the condition that the TOC content is 100±5ppm, the removal rate of TOC by the pyrone-based chelating resin is ≥48%, including but not limited to 48%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%. Further, under the condition that the TOC content is 100±5ppm, the removal rate of TOC by the pyrone-based chelating resin is ≥90%.

[0103] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for aluminum ions is ≥20 mg / g, including but not limited to 20 mg / g, 21 mg / g, 22 mg / g, 23 mg / g, 24 mg / g, 25 mg / g, 26 mg / g, 27 mg / g, 28 mg / g, 29 mg / g or 30 mg / g. Further, the adsorption capacity of the pyrone-based chelating resin for aluminum ions is 20 mg / g to 30 mg / g.

[0104] In some embodiments, under the condition that the aluminum ion content is 110±10ppm, the aluminum ion removal rate of the pyrone-based chelating resin is ≥50%, including but not limited to 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%. Further, under the condition that the aluminum ion content is 110±10ppm, the aluminum ion removal rate of the pyrone-based chelating resin is ≥85%.

[0105] In some embodiments, the adsorption capacity of the pyrone-based chelating resin for rare earth ions is ≤ 0.02 mg / g, including but not limited to 0.001 mg / g, 0.005 mg / g, 0.01 mg / g, 0.015 mg / g or 0.02 mg / g.

[0106] In some embodiments, under the condition that the rare earth ion content is 1080±100ppm, the removal rate of the rare earth ions by the pyrone-based chelating resin is ≤49%, including but not limited to 1%, 2%, 3%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 49%. Further, under the condition that the rare earth ion content is 1080±100ppm, the removal rate of the rare earth ions by the pyrone-based chelating resin is ≤8%.

[0107] In a second aspect of the present application, a method for preparing a pyrone-based chelating resin is provided, which is used to synthesize the pyrone-based chelating resin as described above.

[0108] In some embodiments, the preparation method of the pyrone-based chelating resin comprises the following steps:

[0109] The amino resin, the pyrone compound and the aldehyde compound are subjected to a Mannich reaction to obtain a pyrone-based chelating resin;

[0110] The amino resin has a structure as shown in the general formula (IV), the pyrone compound has a structure as shown in the general formula (V-1) or the general formula (V-2), and the aldehyde compound includes formaldehyde or paraformaldehyde;

[0111] (IV); (V-1); (V-1);

[0112] Wherein, n is a positive integer;

[0113] R 3 and R 4 Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

[0114] In the present application, the Mannich reaction, i.e., the Mannich reaction or the Mann's reaction, refers to an organic synthesis reaction in which a compound containing active hydrogen (usually a carbonyl compound) undergoes a condensation reaction with an amine or formaldehyde to generate a β-amino compound. The reaction product β-amino compound can be called a Mannich base (or a Mannich base, a Mann's base).

[0115] In the preparation method provided by the present application, the α-hydrogen near the carbonyl group of the pyrone compound provides a site for the Mannich reaction, which can directly undergo a condensation reaction with an amino resin, formaldehyde or polyformaldehyde, thereby generating a pyrone-based chelating resin with high aluminum ion and TOC removal rates and low rare earth ion loss rates in one step. At the same time, the preparation method does not require functionalization treatment such as chloromethylation of the pyrone compound, which can reduce the R3 and R 4 The effect of the reaction mixture is beneficial to improving its ion exchange capacity, and can increase the grafting rate of the pyrone functional group on the resin skeleton, which is beneficial to improving its adsorption performance for aluminum ions and TOC. In addition, the preparation method adopts a one-step method to synthesize the pyrone-based chelating resin, which can improve the yield of the pyrone-based chelating resin, reduce the cumbersome steps such as separation and purification, greatly shorten the synthesis cycle, comply with the principles of green chemistry, reduce the risk of environmental pollution, and the raw materials are cheap and easy to obtain, the reaction conditions are relatively mild, and it has the advantages of being green, environmentally friendly, easy to implement, and suitable for industrial application.

[0116] See also Figure 1 , which is a schematic flow diagram of a method for preparing a pyrone-based chelating resin in one embodiment. Figure 1 As shown, the preparation method of the pyrone-based chelating resin comprises the following steps:

[0117] S11: preparing amino resin;

[0118] S12: subjecting the amino resin, the pyrone compound and the aldehyde compound to a Mannich reaction to obtain a pyrone-based chelating resin.

[0119] The preparation method of the pyrone-based chelating resin is described in detail below in a step-by-step manner.

[0120] S11: preparing amino resin.

[0121] It can be understood that the amino resin has a structure as shown in the general formula (IV), and n in the general formula (IV) is selected from a positive integer. In some embodiments, n is selected from a positive integer between 1 and 1000, for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 200, 300, 400, 500 or 1000.

[0122] In some embodiments, optionally, the nitrogen content of the amino resin is 15 at.% to 25 at.%, including but not limited to 15 at.%, 16 at.%, 17 at.%, 18 at.%, 19 at.%, 20 at.%, 21 at.%, 22 at.%, 23 at.%, 24 at.% or 25 at.%. In this way, the amino content on the amino resin can be increased, thereby increasing the grafting rate of the pyrone functional group on the resin skeleton, thereby improving the removal effect of aluminum ions and TOC.

[0123] In some embodiments, the preparation method of the amino resin comprises the Gabriel synthesis method.

[0124] It can be understood that the Gabriel synthesis is a method for synthesizing primary amines, which utilizes potassium phthalimide to react with an alkyl halide to generate an N-alkylated phthalimide (i.e., an intermediate), and then undergoes a decomposition reaction (such as a hydrolysis reaction or a hydrazinolysis reaction) to obtain a primary amine and phthalic acid. The hydrolysis conditions may be acidic or alkaline.

[0125] In some embodiments, the method for preparing the amino resin comprises the following steps:

[0126] mixing the chlorine ball, the first solvent and potassium phthalimide, and performing heating reaction to obtain an intermediate;

[0127] The intermediate and the decomposition agent are mixed to carry out a decomposition reaction to prepare an amino resin.

[0128] In some embodiments, mixing the chlorine ball, the first solvent and potassium phthalimide comprises the following steps: mixing the chlorine ball and the first solvent, performing a first swelling reaction, and adding potassium phthalimide. Thus, the molecular structure of the chlorine ball can be made loose through the first swelling reaction, and potassium phthalimide can easily enter the interior of the chlorine ball to react, thereby accelerating the reaction rate and improving the reaction uniformity.

[0129] In some embodiments, the conditions of the first swelling reaction include: swelling at 20°C to 40°C for 2h to 6h. The temperature of the first swelling reaction may be 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C or 40°C, and the time of the first swelling reaction may be 2h, 3h, 4h, 5h or 6h.

[0130] In some embodiments, the first solvent is a highly polar organic solvent, including but not limited to at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethanol (EtOH), acetonitrile (MeCN) and acetone, and DMF can be further selected.

[0131] In some embodiments, the mass ratio of the chlorine ball to the first solvent is 1:(1-5), including but not limited to 1:1, 1:2, 1:3, 1:4 or 1:5.

[0132] In some embodiments, the mass ratio of chlorine balls to potassium phthalimide is 1:(0.8-1.2), including but not limited to 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2.

[0133] In some embodiments, the conditions for the heating reaction include: reflux reaction at 80°C to 120°C for 6h to 12h. The temperature of the heating reaction may be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, and the heating reaction time may be 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0134] In some embodiments, the decomposition agent includes at least one of ethanolamine, methylamine halogenated salt and hydrazine hydrate. Among them, ethanolamine includes at least one of monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA). The methylamine halogenated salt includes at least one of methylamine hydrochloride, methylamine hydrobromide and methylamine hydroiodide. Further, the decomposition agent is monoethanolamine (MEA).

[0135] In some embodiments, the mass ratio of the chlorine ball to the decomposition agent is 1:(1-2.4), including but not limited to: 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2 or 1:2.4.

[0136] In some embodiments, the conditions for the decomposition reaction include: reflux reaction at 60°C to 120°C for 6h to 12h. The temperature of the decomposition reaction may be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, and the time of the decomposition reaction may be 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0137] In some embodiments, the decomposition reaction is carried out in a second solvent, and the second solvent is a highly polar organic solvent, including but not limited to: at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethanol (EtOH), acetonitrile (MeCN) and acetone, and ethanol (EtOH) can be further selected.

[0138] In some embodiments, the mass ratio of the chlorine ball to the second solvent is 1:(1-5), including but not limited to 1:1, 1:2, 1:3, 1:4 or 1:5.

[0139] In some embodiments, after the heating reaction and / or after the decomposition reaction, a first purification step is further included. The first purification step includes at least one of filtration, cleaning, distillation and drying; the filtration may be ordinary filtration, suction filtration or filter press; the cleaning may be ordinary cleaning, ultrasonic cleaning or Soxhlet extraction, and the cleaning liquid may be pure water, deionized water, methanol, ethanol or acetone; the drying method includes forced air drying or vacuum drying.

[0140] In some embodiments, after the heating reaction, the following steps are further included: filtering the mixed solution containing the intermediate, and washing the obtained filter residue with ethanol and pure water for several times to obtain the intermediate.

[0141] In some embodiments, after the decomposition reaction, the following steps are further included: filtering the mixed solution containing the amino resin, performing Soxhlet extraction on the obtained filter residue using ethanol for 10 hours to 16 hours, and drying at a temperature of 40° C. to 60° C. for 3 hours to 6 hours. The Soxhlet extraction time can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours or 16 hours, the drying temperature can be 40° C., 45° C., 50° C., 55° C. or 60° C., and the drying time can be 3 hours, 4 hours, 5 hours or 6 hours.

[0142] S12: subjecting the amino resin, the pyrone compound and the aldehyde compound to a Mannich reaction to obtain a pyrone-based chelating resin.

[0143] It can be understood that the pyrone compound has a structure as shown in the general formula (V-1) or the general formula (V-2). 3 and R 4 Each occurrence is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl. Further, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, ester, sulfhydryl, amino, substituted or unsubstituted C 1 ~C 6 Alkyl, substituted or unsubstituted C 1 ~C 6 Alkoxy, substituted or unsubstituted C 1 ~C 6 Alkenyl, substituted or unsubstituted C 1 ~C 6 Alkynyl and substituted or unsubstituted C 6 ~C 12 Furthermore, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl, carboxyl, C 1 ~C 6 Alkyl, hydroxy substituted C 1 ~C 6 Alkyl and C 1 ~C 6 One of the alkoxy groups.

[0144] In some embodiments, R 3 and R 4Each occurrence is independently selected from H, hydroxyl, carboxyl, C 1 ~C 3 Alkyl, hydroxy substituted C 1 ~C 3 Alkyl and C 1 ~C 3 One of the alkoxy groups.

[0145] Understandably, “C 1 ~C 3 The "alkyl" may be C 1 Alkyl, C 2 Alkyl or C 3 Alkyl. "Hydroxy-substituted C 1 ~C 3 "Alkyl" means C 1 ~C 3 At least one hydrogen atom on the alkyl group is replaced by a hydroxyl group. 1 ~C 3 The "alkoxy" may be C 1 Alkoxy, C 2 Alkoxy or C 3 Alkoxy.

[0146] In some embodiments, R 3 and R 4 Each occurrence is independently selected from H, hydroxyl (-OH), carboxyl (-COOH), methyl (-CH 3 ), hydroxymethyl (-CH 2 OH) and methoxy (-OCH 3 )

[0147] In some embodiments, the pyrone compound includes at least one of 5-hydroxy-2-hydroxymethyl-4-pyrone, 3-hydroxy-2-methyl-4-pyrone, 5-methoxy-2-hydroxymethyl-4-pyrone, 4-methoxy-6-methyl-2-pyrone, and 2-pyrone-5-carboxylic acid. Among them, 5-hydroxy-2-hydroxymethyl-4-pyrone has a structure as shown in the general formula (V-3), and 5-methoxy-2-hydroxymethyl-4-pyrone has a structure as shown in the general formula (V-4):

[0148] (V-3); (V-4).

[0149] In some embodiments, the amino resin, the pyrone compound and the aldehyde compound are subjected to a Mannich reaction, comprising the following steps: mixing the pyrone compound, the amino resin, the aldehyde compound and the third solvent, heating to 60°C to 100°C, adding a catalyst, and reflux reacting for 6h to 12h to obtain a pyrone-based chelating resin. The temperature of the Mannich reaction can be 60°C, 70°C, 80°C, 90°C or 100°C, and the time of the Mannich reaction can be 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0150] In some embodiments, the third solvent comprises a protic solvent, wherein the protic solvent comprises at least one of water, methanol, ethanol, isopropanol, ethylene glycol and glycerol.

[0151] In some embodiments, the catalyst includes at least one of an inorganic acid and an inorganic base, wherein the inorganic acid includes at least one of hydrochloric acid, sulfuric acid and nitric acid, and the inorganic base includes at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide.

[0152] In some embodiments, the mass ratio of the amino resin, the pyrone compound and the aldehyde compound is 1:(1-3):(0.15-0.45). The mass ratio of the amino resin to the pyrone compound may be 1:1, 1:1.5, 1:2, 1:2.5 or 1:3, and the mass ratio of the amino resin to the aldehyde compound may be 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4 or 1:0.45.

[0153] In some embodiments, the mass ratio of the amino resin, the catalyst and the third solvent is 1:(0.1-0.3):(4-6). The mass ratio of the amino resin to the catalyst may be 1:0.1, 1:0.15, 1:0.2, 1:0.25 or 1:0.3, and the mass ratio of the amino resin to the third solvent may be 1:4, 1:4.5, 1:5, 1:5.5 or 1:6.

[0154] In some embodiments, after the Mannich reaction, a second purification step is further included. The second purification step includes at least one of filtration, washing, distillation and drying; the filtration may be ordinary filtration, suction filtration or filter press; the washing may be ordinary washing, ultrasonic washing or Soxhlet extraction, and the washing liquid may be pure water, deionized water, methanol, ethanol or acetone; the drying method includes forced air drying or vacuum drying.

[0155] In some embodiments, after the Mannich reaction, the following steps are further included: filtering the mixed solution containing the pyrone-based chelating resin, performing Soxhlet extraction on the obtained filter residue using ethanol for 10 hours to 16 hours, and drying at a temperature of 40° C. to 60° C. for 3 hours to 6 hours. The Soxhlet extraction time can be 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours or 16 hours, the drying temperature can be 40° C., 45° C., 50° C., 55° C. or 60° C., and the drying time can be 3 hours, 4 hours, 5 hours or 6 hours.

[0156] In a third aspect of the present application, a method for removing impurities from a rare earth liquid is provided, which is the application of the above-mentioned pyrone-based chelating resin in the field of rare earth product technology.

[0157] In some embodiments, the method for removing impurities from a rare earth solution comprises the following steps: using the above-mentioned pyrone-based chelating resin, or using the pyrone-based chelating resin prepared by the above-mentioned preparation method of the pyrone-based chelating resin, to perform adsorption treatment on the rare earth solution to remove aluminum ions and TOC in the rare earth solution.

[0158] The present invention utilizes the synergistic combination of the multi-oxygen coordination effect and the selective ion exchange capacity of the pyrone-based chelating resin to efficiently remove aluminum ions and TOC in the rare earth feed solution, and significantly reduce the loss rate of rare earth ions. At the same time, the pyrone-based chelating resin is easy to regenerate and can be recycled for a long time, reducing the cost of removing impurities from the rare earth feed solution.

[0159] See also Figure 2 , which is a schematic flow diagram of a method for removing impurities from a rare earth liquid in one embodiment. Figure 2 As shown, the method for removing impurities from rare earth liquid comprises the following steps:

[0160] S21: loading the pyrone-based chelating resin into a chromatography column and pre-treating it with water to obtain a blank column;

[0161] S22: allowing the rare earth material liquid to flow through a blank column for adsorption treatment to obtain an adsorption liquid and an adsorption column;

[0162] S23: desorbing the adsorption column using an acid solution to obtain a desorption liquid and a desorption column;

[0163] S24: Regenerating the desorption column with water to obtain a blank column.

[0164] The present application loads the pyrone-based chelating resin into a chromatography column, uses the separation principle of the chromatography column to remove impurities from the rare earth liquid, and uses acid solution for desorption and water for regeneration, so that the pyrone-based chelating resin can be recycled, which has broad industrial application prospects.

[0165] In some embodiments, the aspect ratio of the chromatography column is 8-20, for example, 8, 10, 12, 14, 16, 18 or 20.

[0166] In some embodiments, in the adsorption treatment, the dosage of the rare earth liquid is 1.5BV~9BV, for example, it can be 1.5BV, 2BV, 3BV, 4BV, 5BV, 6BV, 7BV, 8BV or 9BV; the flow rate of the rare earth liquid is 1BV / h~5BV / h, for example, it can be 1BV / h, 2BV / h, 3BV / h, 4BV / h or 5BV / h.

[0167] In some embodiments, in the desorption treatment, the amount of acid solution used is 2BV~6BV, for example, it can be 2BV, 3BV, 4BV, 5BV or 6BV; the flow rate of the acid solution is 1BV / h~5BV / h, for example, it can be 1BV / h, 2BV / h, 3BV / h, 4BV / h or 5BV / h.

[0168] In some embodiments, the mass fraction of the acid in the acid solution is 5% to 15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%.

[0169] In some embodiments, the acid in the acid solution includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0170] In some embodiments, during pretreatment and / or regeneration treatment, the water may be pure water or deionized water; the amount of water used is 2BV~5BV, for example, it may be 2BV, 3BV, 4BV or 5BV; the flow rate of water is 1BV / h~5BV / h, for example, it may be 1BV / h, 2BV / h, 3BV / h, 4BV / h or 5BV / h.

[0171] In some embodiments, in the rare earth solution, the mass ratio of rare earth element to aluminum ion is (8-12): 1, for example, 8: 1, 9: 1, 10: 1, 11: 1 or 12: 1. Further, in the rare earth solution, the aluminum ion content is 110±10ppm, and the rare earth ion content is 1080±100ppm.

[0172] In some embodiments, in the rare earth solution, the TOC content is 100±5 ppm.

[0173] In some embodiments, the rare earth solution is acidic. Further, the pH of the rare earth solution is 1-4, for example, 1, 1.5, 2, 2.5, 3, 3.5 or 4.

[0174] The following is further described in conjunction with specific examples and comparative examples. The raw materials involved in the following specific examples and comparative examples, if not otherwise specified, can all be commercially available, the instruments used, if not otherwise specified, can all be commercially available, and the processes involved, if not otherwise specified, are all routinely selected by those skilled in the art. Among them, the chlorine ball was purchased from LQ-117 chlorine ball of Wandong High-Tech (Tianchang) Co., Ltd.; the remaining reagents, including potassium phthalimide, ethanolamine, pyrone compounds, paraformaldehyde and solvents, were purchased from Shanghai McLean Biochemical Technology Co., Ltd. and used directly without further purification.

[0175] Example 1

[0176] See also Figure 3 and Figure 4 ,in, Figure 3 Is the synthetic route diagram of the amino resin of the present embodiment, Figure 4 The synthetic route of the pyrone-based chelating resin of this embodiment is shown in FIG. 1 , wherein compound 11 is chlorine ball, compound 12 is N-alkylphthalimide (i.e., intermediate), compound 13 is amino resin, compound 14 is a pyrone compound (5-hydroxy-2-hydroxymethyl-4-pyrone), compound 15 is paraformaldehyde (m is selected from a positive integer), and compounds 16 and 17 are the pyrone-based chelating resins prepared in Example 1.

[0177] The preparation method of the pyrone-based chelating resin of the present embodiment comprises the following steps:

[0178] (1) Preparation of amino resin:

[0179] The chlorine ball was placed in N,N-dimethylformamide (DMF) to swell for 4 hours, potassium phthalimide was added, the temperature was raised to 100°C, and refluxed for 8 hours to obtain a mixed solution containing the intermediate; the filter residue was washed several times with ethanol and pure water to obtain the intermediate. The mass ratio of chlorine ball, potassium phthalimide and DMF was 1:1:4.

[0180] The intermediate, monoethanolamine (MEA) and ethanol were mixed, heated to 80°C, and refluxed for 12 hours to hydrolyze the intermediate to obtain a mixed solution containing amino resin; Soxhlet extraction was performed with ethanol for 12 hours, and the mixture was dried at 60°C for 6 hours to obtain amino resin. The mass ratio of chlorine ball, ethanolamine and ethanol was 1:2.4:5.

[0181] (2) Preparation of pyrone-based chelating resin:

[0182] The amino resin, pyrone compound (5-hydroxy-2-hydroxymethyl-4-pyrone), polyformaldehyde and ethanol were mixed, heated to 80°C, a catalyst (concentrated sulfuric acid) was added, and the mixture was refluxed for 12 hours to allow the amino resin, pyrone compound and polyformaldehyde to undergo a Mannich reaction to obtain a mixed solution containing a pyrone-based chelating resin; the mixture was subjected to Soxhlet extraction with ethanol for 12 hours, then washed with pure water, and dried at 60°C for 6 hours to obtain a pyrone-based chelating resin. The mass ratio of the amino resin, pyrone compound and polyformaldehyde was 1:2:0.3, and the mass ratio of the amino resin, catalyst and ethanol was 1:0.1:5.

[0183] Example 2

[0184] This example is basically the same as Example 1, except that the pyrone compound is replaced by an equal mass of 5-methoxy-2-hydroxymethyl-4-pyrone.

[0185] Example 3

[0186] This example is basically the same as Example 1, except that the reaction conditions of step (2) are different, as follows:

[0187] The amino resin, pyrone compound (5-hydroxy-2-hydroxymethyl-4-pyrone), polyformaldehyde and methanol were mixed, heated to 60°C, a catalyst (sodium hydroxide) was added, and the mixture was refluxed for 12 hours to allow the amino resin, pyrone compound and polyformaldehyde to undergo a Mannich reaction, thereby obtaining a mixed solution containing a pyrone-based chelating resin; the mixture was subjected to Soxhlet extraction with methanol for 12 hours, then washed with pure water, and dried at 60°C for 6 hours to obtain a pyrone-based chelating resin. The mass ratio of the amino resin, pyrone compound and polyformaldehyde was 1:2:0.3, and the mass ratio of the amino resin, catalyst and methanol was 1:0.1:5.

[0188] Example 4

[0189] This example is basically the same as Example 1, except that the reaction conditions of step (2) are different, as follows:

[0190] The amino resin, pyrone compound (5-hydroxy-2-hydroxymethyl-4-pyrone), polyformaldehyde and methanol were mixed, heated to 60°C, a catalyst (concentrated sulfuric acid) was added, and the mixture was refluxed for 12 hours to allow the amino resin, pyrone compound and polyformaldehyde to undergo a Mannich reaction, thereby obtaining a mixed solution containing a pyrone-based chelating resin; the mixture was subjected to Soxhlet extraction with methanol for 12 hours, then washed with pure water, and dried at 60°C for 6 hours to obtain a pyrone-based chelating resin. The mass ratio of the amino resin, pyrone compound and polyformaldehyde was 1:2:0.3, and the mass ratio of the amino resin, catalyst and methanol was 1:0.1:5.

[0191] Example 5

[0192] This embodiment is substantially the same as Embodiment 1, except that the mass ratio of the amino resin, the pyrone compound and the paraformaldehyde is 1:1:0.15.

[0193] Example 6

[0194] This embodiment is substantially the same as embodiment 1, except that the mass ratio of the amino resin, the pyrone compound and the paraformaldehyde is 1:3:0.45.

[0195] Comparative Example 1

[0196] This comparative example uses a commercially available aminocarboxylic acid adsorption resin for aluminum removal, and the structure is as follows:

[0197] .

[0198] Comparative Example 2

[0199] This comparative example uses a commercially available polyhydroxyglucose adsorption resin for removing TOC, and the structure is as follows:

[0200] .

[0201] Comparative Example 3

[0202] This comparative example adopts a pyrone-based chelating resin with the following structure:

[0203] .

[0204] Test Case

[0205] 1. Infrared spectrogram: The pyrone-based chelating resin of Example 1 was subjected to infrared spectroscopy characterization. The results are as follows: Figure 5 As shown. Figure 5 Medium, 3251cm -1The infrared absorption peak at 1620cm belongs to the stretching vibration peak of the hydroxyl group on the pyrone functional group. The conjugation effect of the two carbon-carbon double bonds causes the infrared absorption peak of the carbonyl group on the pyrone functional group to move to a lower wave number. -1 The characteristic peak at is attributed to the carbonyl stretching vibration peak on the pyrone functional group, which indicates that the pyrone functional group having the structure shown in general formula (II-3) is grafted onto the main chain skeleton of the pyrone chelating resin of Example 1.

[0206] 2. Adsorption performance test:

[0207] (1) Filling and pretreatment: 10 mL of pyrone-based chelating resin was loaded into a chromatography column with a height-to-diameter ratio of 10, and pretreated with pure water with a volume of 5 BV and a flow rate of 1 BV / h to obtain a blank column;

[0208] (2) Adsorption: The rare earth liquid is injected from one end and flows through the blank column for adsorption treatment. The volume of the rare earth liquid is 10 BV and the flow rate of the rare earth liquid is 1 BV / h to obtain an adsorption column and adsorption liquid;

[0209] (3) Desorption: A hydrochloric acid solution with a mass concentration of 10% is flowed through the adsorption column for desorption treatment. The volume of the hydrochloric acid solution is 5 BV, and the flow rate of the hydrochloric acid solution is 1 BV / h. Every 1 BV of the desorption liquid is retained to obtain a desorption column and a desorption liquid.

[0210] (4) Regeneration: Use pure water to flow through the desorption column for regeneration. The volume of pure water is 5 BV and the flow rate is 1 BV / h to obtain a blank column.

[0211] (5) Repeat steps (2) to (4) for a total of 5 cycles.

[0212] The rare earth ion content and aluminum ion content in the rare earth feed solution (pH=3) and the adsorption liquid in the first cycle were tested by ICP-MS method, and the TOC content was determined by TOC analyzer, and the results are listed in Table 1. The calculation formula of the loss rate or removal rate is: (the content of rare earth feed solution-the content of adsorption liquid) ÷ the content of rare earth feed solution × 100%.

[0213] Table 1. Adsorption effect of pyrone-based chelating resin on rare earth liquid

[0214]

[0215] It can be clearly seen from Table 1 above that when the pyrone-based chelating resins prepared in Examples 1 to 6 of the present application are used for adsorption treatment of rare earth liquid, the removal rate of aluminum ions reaches more than 50%, and the removal rate of TOC reaches more than 48%. At the same time, the loss rate of rare earth ions is reduced to less than 49%, indicating that the pyrone-based chelating resins provided by the present application can selectively remove impurities such as aluminum ions and TOC, and effectively avoid the loss of rare earth resources.

[0216] It can be seen from Examples 1, 5 and 6 that, in the Mannich reaction process, increasing the amount of the pyrone compound is beneficial to increasing the grafting rate of the pyrone functional group on the resin skeleton, thereby improving the adsorption effect of the pyrone-based chelating resin on aluminum ions and TOC.

[0217] Using concentrated sulfuric acid as a catalyst, the obtained pyrone-based chelating resin is an H-type resin. From the comparison of Examples 1 and 4, it can be seen that the temperature of the Mannich reaction of Example 4 is relatively low, so that the reaction rate is relatively low, and the grafting rate of the pyrone functional group decreases, so the adsorption effect on aluminum ions and TOC deteriorates. Compared with Example 4, Example 3 uses NaOH as a catalyst, which is conducive to accelerating the reaction rate of the Mannich reaction. The obtained pyrone-based chelating resin belongs to a Na-type resin, and its adsorption effect on rare earth ions, aluminum ions and TOC is better than that of the H-type resin, but the adsorption selectivity to aluminum ions is reduced.

[0218] Compared with Example 1, Comparative Example 1 uses aminocarboxylic acid adsorption resin, and the removal rate of aluminum ions reaches 92.67%, but the removal rate of TOC is poor and the loss rate of rare earth ions is high; Comparative Example 2 uses polyhydroxyglucose adsorption resin, and the removal rate of TOC reaches 94.90%, but the removal rate of aluminum ions is poor; in the pyrone-based chelating resin of Comparative Example 3, the pyrone functional group is linked to the resin skeleton through two -NH-, so that its adsorption selectivity for aluminum ions is reduced, and the adsorption effect for rare earth ions is better, so the loss rate of rare earth ions is increased.

[0219] After each cycle, the TOC removal rate of the pyrone-based chelating resin of Example 1 was tested and the results are shown in Figure 6 .like Figure 6 As shown, after 5 cycles, the TOC removal rate of the pyrone-based chelating resin of Example 1 was still maintained above 92%, showing excellent regeneration performance and recyclability.

[0220] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0221] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of protection of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A pyrone-based chelating resin, characterized in that, It has a structure as shown in the general formula (I): （Ⅰ）； （Ⅱ-1）； （Ⅱ-2）； Wherein, n is selected from a positive integer; R1 and R2 are each independently selected from H, a structure represented by the general formula (II-1) and a structure represented by the general formula (II-2), and R1 and R2 are not selected from H at the same time; Each occurrence of R3 and R4 is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

2. The pyrone-based chelating resin according to claim 1, wherein Each occurrence of R3 and R4 is independently selected from one of H, hydroxyl, carboxyl, C1-C3 alkyl, hydroxyl-substituted C1-C3 alkyl and C1-C3 alkoxy.

3. The pyrone-based chelating resin according to claim 2, wherein Each occurrence of R3 and R4 is independently selected from one of H, hydroxy, carboxyl, methyl, hydroxymethyl and methoxy.

4. The pyrone-based chelating resin according to any one of claims 1 to 3, characterized in that At least one of the following conditions is met: (1) The adsorption capacity of the pyrone-based chelating resin for TOC is ≥ 1800 mg / g; (2) The adsorption capacity of the pyrone-based chelating resin for aluminum ions is ≥ 20 mg / g; (3) The adsorption capacity of the pyrone-based chelating resin for rare earth ions is ≤0.02 mg / g.

5. A method for preparing a pyrone-based chelating resin, characterized in that: The following steps are involved: subjecting an amino resin, a pyrone compound and an aldehyde compound to a Mannich reaction to obtain the pyrone-based chelating resin; The amino resin has a structure as shown in the general formula (IV), the pyrone compound has a structure as shown in the general formula (V-1) or the general formula (V-2), and the aldehyde compound includes formaldehyde or paraformaldehyde; （Ⅳ）； （Ⅴ-1）； （Ⅴ-1）； Wherein, n is a positive integer; Each occurrence of R3 and R4 is independently selected from one of H, hydroxyl, carboxyl, ester, thiol, amino, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl and substituted or unsubstituted aryl.

6. The method for preparing a pyrone-based chelating resin according to claim 5, wherein The pyrone compound includes at least one of 5-hydroxy-2-hydroxymethyl-4-pyrone, 3-hydroxy-2-methyl-4-pyrone, 5-methoxy-2-hydroxymethyl-4-pyrone, 4-methoxy-6-methyl-2-pyrone and 2-pyrone-5-carboxylic acid.

7. The method for preparing a pyrone-based chelating resin as claimed in claim 5 or 6, wherein: The amino resin, the pyrone compound and the aldehyde compound are subjected to a Mannich reaction, comprising the following steps: The amino resin, the pyrone compound, the aldehyde compound and the third solvent are mixed, the temperature is raised to 60° C. to 100° C., a catalyst is added, and the mixture is refluxed for 6 h to 12 h to obtain the pyrone-based chelating resin.

8. The method for preparing a pyrone-based chelating resin according to claim 7, wherein At least one of the following conditions is met: (1) The mass ratio of the amino resin, the pyrone compound and the aldehyde compound is 1:(1-3):(0.15-0.45); (2) The mass ratio of the amino resin, the catalyst and the third solvent is 1:(0.1-0.3):(4-6); (3) The catalyst comprises at least one of an inorganic acid and an inorganic base; (4) The third solvent includes a protic solvent.

9. The method for preparing a pyrone-based chelating resin according to claim 7, wherein The preparation method of the amino resin comprises the Gabriel synthesis method.

10. A method for removing impurities from a rare earth liquid, characterized in that: The following steps are involved: A rare earth liquid is subjected to adsorption treatment using the pyrone-based chelating resin as described in any one of claims 1 to 4, or a pyrone-based chelating resin prepared by the preparation method of the pyrone-based chelating resin as described in any one of claims 5 to 9, so as to remove aluminum ions and TOC in the rare earth liquid.

11. The method for removing impurities from rare earth liquid according to claim 10, characterized in that: The method for removing impurities from the rare earth liquid comprises the following steps: The pyrone-based chelating resin is loaded into a chromatography column and pre-treated with water to obtain a blank column; Allowing the rare earth material liquid to flow through the blank column for adsorption treatment to obtain an adsorption liquid and an adsorption column; Desorbing the adsorption column by using an acid solution to obtain a desorption liquid and a desorption column; The desorption column is regenerated by using water to obtain the blank column.

12. The method for removing impurities from rare earth liquid according to claim 11, characterized in that: The following conditions are met: (1) The height-to-diameter ratio of the chromatography column is 8 to 20; (2) In the adsorption treatment, the dosage of the rare earth liquid is 1.5 BV to 9 BV, and the flow rate of the rare earth liquid is 1 BV / h to 5 BV / h; (3) In the desorption process, the amount of the acid solution is 2BV~6BV, and the flow rate of the acid solution is 1BV / h~5BV / h; (4) The mass fraction of the acid in the acid solution is 5% to 15%; (5) The acid in the acid solution includes at least one of hydrochloric acid, sulfuric acid and nitric acid; (6) In the pretreatment and / or the regeneration treatment, the amount of water used is 2BV~5BV, and the flow rate of the water is 1BV / h~5BV / h.

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