CN112717886A

CN112717886A - Rare earth element adsorbent and preparation method and application thereof

Info

Publication number: CN112717886A
Application number: CN202011458011.6A
Authority: CN
Inventors: 陈运法; 王延华; 仉小猛; 杜英超; 李正辰; 刘翔; 闫敬民; 叶树峰; 魏连启
Original assignee: Jiangxi Rare Earth Research Institute Chinese Academy Of Sciences; Institute of Process Engineering of CAS
Current assignee: Jiangxi Rare Earth Research Institute Chinese Academy Of Sciences; Institute of Process Engineering of CAS
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-04-30

Abstract

The invention relates to a rare earth element adsorbent and a preparation method and application thereof. The preparation method comprises the following steps: (1) adding auxiliary agents and modifiers to a solution containing divalent metal ions and trivalent metal ions to obtain intermediate (2) subjecting the intermediate solution obtained in step (1) to a modification reaction to obtain the rare earth element adsorbent. The preparation method provided by the present invention uses metal ions as the main raw material and is treated with a modified body rich in specific functional groups, so that a large number of functionalized hydrotalcite-like materials can be prepared for the recovery and purification of rare earth elements, the adsorption balance is significantly improved, and the saturated adsorption The capacity is between 0.5‑5g/g.

Description

Rare earth element adsorbent and preparation method and application thereof

Technical Field

The invention relates to the field of rare earth adsorption, in particular to a rare earth element adsorbent and a preparation method and application thereof.

Background

At present, rare earth resources in China are very rich, and the yield is the first in the world and accounts for about 60% of the total amount of the world. The application of rare earth elements is developed vigorously, and the development of the rare earth elements is expanded to various aspects of science and technology, particularly the development and application of some modern novel functional materials, and the high-purity rare earth elements become indispensable raw materials. Although China has made great progress in the exploitation of rare earth, the technology and equipment for separating rare earth are backward, and the purification process of high-purity rare earth still has obvious shortages. The purification of rare earth in a single rare earth solution at a certain concentration is an important part of the purification process of high-purity rare earth, and especially when the concentration of the rare earth solution is at a lower level (1-1000 mg/L), the extraction difficulty is further increased. Therefore, the method has important significance for enriching and purifying the rare earth elements in the single rare earth solution with lower concentration.

Aiming at the purification of rare earth in a rare earth solution, the currently researched methods mainly comprise an adsorption method, a precipitation method, an extraction method, a membrane separation method and the like.

For example, CN101974690A adopts a method of combining precipitation and extraction to extract rare earth, and discloses a process for recovering rare earth from rare earth mining wastewater by a precipitation-extraction method, which mainly comprises the steps of treating the rare earth wastewater by calcium hydroxide precipitation and P507 organic extraction methods, recovering the rare earth therein, preparing rare earth feed liquid with the concentration of more than 1.2M, and directly feeding the rare earth feed liquid to rare earth smelting for separating rare earth elements. The method has the advantages that the recovery rate of the rare earth reaches more than 85 percent, trace low-concentration rare earth in the wastewater is fully recycled, the waste of resources is reduced, and precious rare earth resources are recycled to the maximum extent. The recovery rate reaches about 85 percent, but the extraction purity is not high, and the secondary pollution is easily caused by the dissolution loss of an extracting agent.

CN102352448A discloses a method for recovering rare earth from low-concentration rare earth solution by Prussian blue colloidal nano particles (PB-CNP) through an adsorption method and a membrane separation method. Firstly, synthesizing stable PB-CNP colloidal solution, filling the stable PB-CNP colloidal solution into a bag made of a dialysis membrane, contacting the dialysis bag filled with PB-CNP suspension with rare earth feed liquid (pH value is 4-7), and contacting rare earth ions with PB-CNP through membrane pores to be adsorbed. The rare earth can be desorbed from the PB-CNP suspension liquid absorbed with the rare earth ions by using a dilute acid solution, thereby achieving the purpose of recovering the rare earth. The PB-CNP suspension and the rare earth feed liquid to be treated can also be respectively placed on different channels on two sides of the membrane component to flow in a countercurrent manner, so that the high-efficiency enrichment effect is achieved. The method has the advantages of simple process, large rare earth loading capacity, high rare earth recovery rate and the like, can be widely used for rare earth feed liquid of rare earth mines and separation plants, particularly for completely removing and recovering rare earth ions in low-concentration rare earth wastewater, and has wide application prospect. Although the method has high rare earth extraction efficiency, the Prussian blue colloidal nanoparticle adsorbent has no economic benefit, and the dialysis membrane has the problem of small treatment capacity.

However, the recovery rate is low, impurities are more and the adsorption capacity of the adsorbent is small when the rare earth elements are recovered by adopting an adsorption method at the present stage.

Disclosure of Invention

In view of the problems in the prior art, the invention aims to provide a rare earth element adsorbent, and a preparation method and application thereof, and by improving the preparation method of the hydrotalcite-like adsorbent, a large amount of functional group hydrotalcite-like materials which can be applied to rare earth element recovery and purification can be prepared, so that the problems of low rare earth recovery efficiency, small equilibrium capacity, low extraction purity and the like of the adsorbent in the prior art are solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a method for preparing a rare earth element adsorbent, comprising the steps of:

(1) adding an auxiliary agent and a modifier into a solution containing divalent metal ions and trivalent metal ions to obtain an intermediate solution;

(2) and (2) carrying out modification reaction on the intermediate solution obtained in the step (1) to obtain the rare earth element adsorbent.

The preparation method provided by the invention takes metal ions as a main raw material, and is treated by a modifier rich in a specific functional group, so that a large amount of functional group hydrotalcite-like materials applied to rare earth element recovery and purification can be prepared, the adsorption balance is obviously improved, and the saturated adsorption capacity is between 0.5 and 5 g/g.

As a preferred technical solution of the present invention, the divalent metal ions in step (1) include 1 or a combination of at least 2 of divalent magnesium ions, divalent cobalt ions, ferrous ions, divalent nickel ions, divalent copper ions, divalent manganese ions, or divalent zinc ions. The combination may be a combination of divalent magnesium ions and divalent cobalt ions, a combination of divalent ferrous ions and divalent nickel ions, or a combination of divalent copper ions and divalent zinc ions, and the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.

Preferably, the trivalent metal ions of step (1) include 1 or a combination of at least 2 of trivalent aluminum ions, trivalent iron ions, trivalent manganese ions, trivalent chromium ions, or trivalent indium ions. The combination may be a combination of trivalent aluminum ions and trivalent iron ions, a combination of trivalent manganese ions and trivalent chromium ions, a combination of trivalent iron ions and trivalent silver ions, or the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.

In a preferred embodiment of the present invention, the molar ratio of the divalent metal element to the trivalent metal element in the solution in step (1) is 1 (0.3-3), and may be, for example, 1:0.3, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8 or 1:3, but is not limited to the above-mentioned values, and other values not listed in this range are also applicable.

As a preferred technical scheme of the invention, the auxiliary agent in the step (1) comprises 1 or at least 2 of sodium hydroxide, sodium carbonate, melamine or urea. The combination may be a combination of sodium hydroxide and sodium carbonate, a combination of sodium carbonate and melamine or a combination of melamine and urea, etc., but is not limited to the listed combinations, and other combinations not listed within the scope are equally applicable.

In a preferred embodiment of the present invention, the amount of the auxiliary agent added in step (1) is 1 to 100% by mass of the divalent metal ion in the solution, and may be, for example, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or the like, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.

As a preferred embodiment of the present invention, the modifying agent in step (1) comprises 1 or a combination of at least 2 of compounds containing at least 1 of hydroxyl, carboxyl, carbonyl, amino, imino, thio or sulfo. The combination may be a combination of a hydroxyl group and a carboxyl group, a combination of a carbonyl group and an amino group, a combination of an imino group and a mercapto group, or a combination of an amino group and a sulfo group, and the like, but is not limited to the listed combinations, and other combinations not listed in this range are also applicable.

In the present invention, the modifier includes a compound containing at least 1 of a hydroxyl group, a carboxyl group, a carbonyl group, an amino group, an imino group, a mercapto group, or a sulfo group, and may be an alcohol, a carboxylic acid, a sulfide, or a nitride.

The alcohols contain hydroxyl groups as much as possible and are liquid at normal temperature, such as methanol, ethanol or propanol.

The carboxylic acids should contain as many carboxyl groups as possible and should be liquid or solid at ordinary temperature, such as formic acid, acetic acid or oxalic acid.

The sulfide has oxidizing property, and is liquid or solid at normal temperature, such as sulfonate, sodium sulfamate, mercaptan, phenol sulfhydrate or benzene sulfonic acid.

The nitride has oxidizing property, and is liquid or solid at normal temperature, such as amino acid or imino acid.

As a preferred technical scheme of the invention, the modifier in the step (1) comprises a liquid modifier and/or a solid modifier.

Preferably, the modifying agent in step (1) is a liquid modifying agent, and the amount of the liquid modifying agent added is 1 to 30% of the mass of water in the solution, and may be, for example, 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%, and the like, but is not limited to the recited values, and other values not recited in the range are also applicable.

Preferably, the modifying agent in step (1) is a solid modifying agent, and the amount of the solid modifying agent added is 1-10% of the mass of water in the solution, and may be, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the recited values, and other values not recited in this range are also applicable.

Preferably, the modification reaction of step (2) is carried out in a reaction kettle.

Preferably, the volume of the solution in the reaction vessel in the modification reaction in step (2) is 50 to 70% of the volume of the reaction vessel, for example, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, or 70%, etc., but is not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the modification reaction in step (2) reaction temperature is 90-150 ℃, for example can be 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees or 150 degrees C, but not limited to the enumerated values, in the range of other values are also applicable.

Preferably, the modification reaction in step (2) is carried out for 2 to 8 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, but not limited to the recited values, and other values not recited in the range are also applicable.

As a preferred technical scheme of the invention, the preparation method comprises the following steps:

(2) carrying out modification reaction on the intermediate solution obtained in the step (1) to obtain the rare earth element adsorbent;

the modifier in the step (1) comprises 1 or the combination of at least 2 of compounds containing hydroxyl, carboxyl, carbonyl, amino, imino, sulfhydryl or sulfo, the modifier comprises a liquid modifier and/or a solid modifier, the modifier is a liquid modifier, the addition amount of the liquid modifier is 1-30% of the mass of water in the solution, the modifier is a solid modifier, and the addition amount of the solid modifier is 1-10% of the mass of water in the solution; the reaction temperature of the modification reaction is 90-150 ℃.

In a second aspect, the present invention provides the rare earth element adsorbent prepared by the method of the first method, wherein the adsorbent is a hydrotalcite-like adsorbent.

In a third aspect, the present invention provides the use of an adsorbent for a rare earth element, the use comprising adsorbing a solution containing a rare earth element with the adsorbent of the second aspect.

Preferably, the addition amount of the adsorbent and the liquid-solid ratio g/L of the rare earth element-containing solution are (0.5-1):1, and may be, for example, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1, but not limited to the values listed, and other values not listed in this range are also applicable.

Preferably, the pH of the rare earth element-containing solution is 2 to 13, and may be, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or the like, but is not limited to the recited values, and other values not recited in this range are also applicable, preferably 5 to 9.

Preferably, the rare earth element in the rare earth element-containing solution includes 1 or a combination of at least 2 of La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Sc, or Y. The combination may be a combination of La and Ce, a combination of Pr and Nd, a combination of Eu and Tb, a combination of Dy and Ho, or a combination of Tm and Sc, etc., but is not limited to the combinations enumerated, and other combinations not enumerated within this range are also applicable.

The mechanism of adsorbing, recovering and purifying the rare earth elements in the solution by the hydrotalcite-like adsorbent mainly relates to the following steps: electrostatic interaction, chelation and ion exchange, and the modified ion pairs or electron pairs can be used for adsorbing rare earth elements in the solution, and can be desorbed by low-concentration alkali liquor (such as 0.1-0.5M sodium hydroxide solution or potassium hydroxide solution) to recover the adsorbed elements.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the preparation method provided by the invention takes metal ions as a main raw material, and is modified by a modifier rich in a specific functional group, so that a large amount of functional group hydrotalcite-like material applied to rare earth element recovery and purification can be prepared, the adsorption equilibrium capacity is large, the equilibrium capacity is 0.5-5g/g, the recovery efficiency of rare earth is more than 98%, and the purity of desorption solution after desorption is as high as 99.9%.

(2) The hydrotalcite-like adsorbent prepared by the preparation method provided by the invention has the material morphology of sheet, lamellar, petal-shaped, sea urchin-like and the like, and the size is 0.1-10 mu m; the method has the advantages of wide application range, suitability for a slightly acidic environment, suitability for a neutral or alkaline environment, simple process and flow, short reaction time, wide parameter adjustable range and strong repeatability, and is beneficial to realizing industrial production.

Drawings

FIG. 1 is an SEM photograph of the adsorbent obtained in example 1 of the present invention;

FIG. 2 is an SEM photograph of the adsorbent obtained in comparative example 3 of the present invention.

The present invention is described in further detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

Detailed Description

To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:

example 1

The embodiment provides a rare earth element adsorbent, which is prepared by the following method:

adding Mn (NO)₃)₂·6H₂O、Al(NO₃)₃·9H₂And preparing the O into a mixed solution according to the molar ratio of Mn to Al of 2: 1. Respectively reacting pentanediol and Na₂CO₃Adding into the mixed solution to obtain intermediate solution, wherein the addition amount of pentanediol is 10% of the water mass in the mixed solution, and Na₂CO₃The addition amount of Mn (NO)₃)₂·6H₂10% of the mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, carrying out modification synthesis reaction for 8 hours at 120 ℃, wherein the volume of the intermediate liquid accounts for 60% of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the hydroxylated hydrotalcite-like adsorbent, wherein an SEM photograph is shown in figure 1, and the saturated adsorption capacity of the product to samarium ions is detailed in table 1.

Example 2

adding Mn (NO)₃)₂·6H₂O、Mg(NO₃)₂·6H₂O、Al(NO₃)₃·9H₂And preparing the O into a mixed solution according to the molar ratio of Mn to Mg to Al of 1:1: 1. Respectively adding sodium sulfamate and urea into the mixed solution to obtain intermediate solution, wherein the addition amount of the sodium sulfamate is 3% of the mass of water in the mixed solution, and the addition amount of the urea is Mn (NO)₃)₂·6H₂O and Mg (NO)₃)₂·6H₂50% of the total mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, performing modification synthesis reaction at 120 ℃ for 8 hours, wherein the volume of the intermediate liquid accounts for 60 percent of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the sulfydrylThe saturated adsorption capacity of the base hydrotalcite-like adsorbent to samarium ions is detailed in table 1.

Example 3

adding Mn (NO)₃)₂·6H₂O、Mg(NO₃)₂·6H₂O、Al(NO₃)₃·9H₂O、Fe(NO₃)₃·9H₂And preparing the O into a mixed solution according to the molar ratio of Mn to Mg to Al to Fe of 2:2:1: 1. Respectively mixing glycerol, sodium sulfamate and Na₂CO₃Adding urea into the mixed solution to obtain an intermediate solution, wherein the addition amounts of glycerol and sodium sulfamate are respectively 5% and 2% of the mass of water in the mixed solution, and Na₂CO₃And urea in an amount of Mn (NO)₃)₂·6H₂O and Mg (NO)₃)₂·6H₂5% and 25% of the total mass of O. Transferring the intermediate liquid into a high-pressure reaction kettle, carrying out modification synthesis reaction for 8 hours at 120 ℃, wherein the volume of the intermediate liquid accounts for 60% of the volume of the high-pressure reaction kettle, naturally cooling, filtering and drying the product to obtain the hydroxyl sulfhydrylation hydrotalcite-like adsorbent, and the saturated adsorption capacity to samarium ions is detailed in table 1.

Comparative example 1

The difference from example 1 is that no auxiliary agent or modifier is added, and after natural cooling, almost no product is produced, and hydroxylated hydrotalcite is not obtained.

Comparative example 2

The difference from example 1 is only that the molar ratio of the divalent metal element to the trivalent metal element in the solution is 20:1, and after natural cooling, almost no product is produced, and hydroxylated hydrotalcite-like compound cannot be obtained.

Comparative example 3

The difference from example 2 is that no modifier is added to obtain hydrotalcite-like adsorbent, and the SEM photograph is shown in FIG. 2.

Comparative example 4

The only difference from example 3 is that the temperature of the modification reaction was 60 ℃ to obtain a small amount of the hydroxysulfylated hydrotalcite-like compound.

Comparative example 5

The difference from example 1 is only that no auxiliary agent is added, and a small amount of hydrotalcite-like adsorbent is obtained.

Application example 1

0.5g of the adsorbents obtained in examples 1 to 3 and comparative examples 3 to 5 was added to a samarium ion solution having a pH of 7 and a concentration of 100mg/L to adsorb the samarium ions, and after the adsorption was completed, 0.1moL/L of sodium hydroxide solution was used to desorb the samarium ions, and the desorption results of the adsorption alloys are shown in table 1.

TABLE 1

	Saturated adsorption capacity g/g	Percent recovery%	Purity of the analysis solution/%)	Analysis rate/%
					Example 1	0.5	90	99.9	99.9
Example 2	0.8	98	99.9	99.9
					Example 3	1.5	99	99.9	99.9
Comparative example 3	0.1	30	90	90
					Comparative example 4	0.1	30	90	90
Comparative example 5	0.1	30	90	90

The results of the above examples and comparative examples show that a large amount of functional group hydrotalcite-like materials applied to rare earth element recovery and purification can be prepared by improving the preparation method of the hydrotalcite-like adsorbent, and the problems of low rare earth recovery efficiency, small equilibrium capacity, low extraction purity and the like of the adsorbent in the prior art are solved.

The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. a preparation method of rare earth element adsorbent, is characterized in that, described preparation method comprises the steps:

(1) adding auxiliary agent and modifier to the solution containing divalent metal ion and trivalent metal ion to obtain intermediate solution;

(2) subjecting the intermediate solution obtained in step (1) to a modification reaction to obtain the rare earth element adsorbent.

2. The preparation method of claim 1, wherein the divalent metal ions in step (1) comprise magnesium ions, divalent cobalt ions, ferrous ions, divalent nickel ions, divalent copper ions, divalent One or a combination of at least two of manganese ions or zinc ions;

Preferably, the trivalent metal ions in step (1) include one or a combination of at least two of aluminum ions, trivalent iron ions, trivalent manganese ions, trivalent chromium ions or trivalent indium ions.

3. The preparation method according to claim 1 or 2, wherein the molar ratio of divalent metal element and trivalent metal element in the solution described in step (1) is 1:(0.3-3).

4. The preparation method according to any one of claims 1-3, wherein the auxiliary agent described in step (1) comprises one or at least two combinations in sodium hydroxide, sodium carbonate, melamine or urea .

5. The preparation method according to any one of claims 1-4, wherein the addition amount of the auxiliary agent in step (1) is 1-100% of the mass of the divalent metal ions in the solution.

6. The preparation method according to any one of claims 1-5, wherein the modifier in step (1) comprises at least one of hydroxyl, carboxyl, carbonyl, amino, imino, mercapto or sulfo groups 1 or a combination of at least 2 of the compounds.

7. The preparation method according to claim 1-6, wherein the modifier in step (1) comprises a liquid modifier and/or a solid modifier;

Preferably, the modifier in step (1) is a liquid modifier, and the amount of the liquid modifier added is 1-30% of the water mass in the solution;

Preferably, the modifier in step (1) is a solid modifier, and the amount of the solid modifier added is 1-10% of the water mass in the solution;

Preferably, the modification reaction of step (2) is carried out in a reactor;

Preferably, in the modification reaction of step (2), the volume of the solution in the reactor is 50-70% of the volume of the reactor;

Preferably, the reaction temperature of the modification reaction in step (2) is 90-150°C;

Preferably, the modification reaction time of step (2) is 2-8h.

8. The preparation method according to any one of claims 1-7, wherein the preparation method comprises the steps:

(2) subjecting the intermediate solution obtained in step (1) to a modification reaction to obtain the rare earth element adsorbent;

Step (1) The modifier includes one or a combination of at least two of the compounds containing hydroxyl, carboxyl, carbonyl, amino, imino, sulfhydryl or sulfo, and the modifier includes a liquid modifier and/or Solid modifier, the modifier is a liquid modifier, the addition amount of the liquid modifier is 1-30% of the water mass in the solution, the modifier is a solid modifier, and the solid modifier is added in an amount of 1-10% of the water mass in the solution; the reaction temperature of the modification reaction is 90-150°C.

9 . A rare earth element adsorbent, characterized in that, the adsorbent is obtained by the preparation method according to any one of claims 1 to 8 , and the adsorbent is a hydrotalcite-like adsorbent.

10. An application of a rare earth element adsorbent, characterized in that the application comprises using the adsorbent of claim 9 to adsorb a solution containing rare earth elements;

Preferably, the added amount of the adsorbent and the liquid-solid ratio g/L of the solution containing rare earth elements are (0.5-1):1;

Preferably, the pH of the solution containing rare earth elements is 2-13, preferably 5-9;

Preferably, the rare earth element in the rare earth element-containing solution includes one or a combination of at least two of La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Sc or Y .