Method for preparing rare earth enrichment through rotational flow electrolysis

Abstract

The invention relates to a method for preparing a rare earth enriched substance through rotational flow electrolysis, which comprises the following steps: carrying out rotational flow electrolysis on a rare earth ion solution in a cathode region by using an electrolytic tank, continuously rotating a cathode along a central axis in the rotational flow electrolysis process, and carrying out solid-liquid separation on a product obtained in the cathode region after the rotational flow electrolysis is finished to obtain the rare earth enriched substance, the problems of impurity coprecipitation caused by poor mass transfer on the surface of the electrode and cell voltage rise caused by electrode scaling in a traditional electrolysis enrichment method are solved, the rotating cathode is adopted, the mass transfer process on the surface of the electrode is enhanced in situ through continuous rotation, the impurity coprecipitation and electrode scaling are greatly reduced, and the quality of the electrode is improved. The separation efficiency of rare earth and impurities is enhanced, effective utilization of electric energy is facilitated, and the increase of cell voltage can be effectively inhibited, so that the grade of rare earth enrichment prepared through electrolysis is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a method for preparing rare earth enrichments by cyclone electrolysis. Background Technology

[0002] In recent years, with the rapid development of cutting-edge technology fields such as new energy vehicles, artificial intelligence, quantum information, integrated circuits, nuclear industry, aerospace and deep-sea exploration, the demand for rare earth elements, as an indispensable resource supporting the development of these fields, has been continuously increasing. The ever-increasing mining of rare earth resources has led to problems such as mine pollution and excessive discharge of saline wastewater. Therefore, how to efficiently and effectively enrich rare earth ions from solutions and obtain high-grade concentrates has become an important research topic.

[0003] Currently, the main methods for enriching rare earth ions from solution include chemical precipitation and extraction. The principle of chemical precipitation is to add an excess of chemical precipitants, such as ammonium salts, alkalis, or alkali metal compounds, to the solution, converting rare earth ions into compounds with low solubility, thereby enriching the rare earth elements. This method, as a highly efficient enrichment technique, has advantages such as simple process and large throughput. However, this process requires the addition of excessive chemical reagents to the solution, easily introducing a large number of impurity ions and generating saline wastewater. Furthermore, some reagents do not participate in the reaction and co-precipitate with the rare earth ions, reducing the grade of the enriched product.

[0004] For example, existing technology discloses a method for recovering rare earth elements from leaching mother liquor using sodium aluminate and magnesium oxide as precipitants to prepare rare earth enrichments. In this process, a large number of impurity ions are introduced into the leaching mother liquor, which reduces the rare earth content of the enrichment and causes the problem of saline wastewater discharge.

[0005] Another patent discloses a method for enriching rare earth ions. This method involves mixing a solid organophosphorus precipitant with an alkaline liquid to obtain a saponified organophosphoric acid solution. After mixing and reacting the saponified organophosphoric acid solution with a rare earth ion-containing liquid, solid-liquid separation is performed to obtain rare earth enrichment. In this process, an organic phosphorus-containing reagent is added, which can easily lead to phosphorus pollution and COD pollution.

[0006] Compared to traditional chemical precipitation and extraction methods, electrolysis offers advantages such as being green and producing no high-salt wastewater. Its main principle is to adjust the pH of the solution to a certain range by generating hydroxide ions in situ on the cathode surface during water electrolysis, converting rare earth ions in the solution into precipitates with low solubility. This process converts electrical energy into chemical energy, achieving green and efficient separation and enrichment of rare earth elements without introducing chemical reagents. However, this method is prone to co-precipitation of impurities when processing solutions containing a large number of impurities, significantly reducing the separation efficiency between rare earth elements and impurities, leading to increased impurity content in the rare earth enrichment and consequently increasing the cost of subsequent acid leaching.

[0007] For example, existing technology discloses a method for the selective separation of copper and beryllium in a sulfuric acid system. This method eliminates the concentration polarization of copper ions by rotating the electrodes, thereby enhancing the electrochemical reaction process of copper electrodeposition. However, if the method in this patent is used directly for electrolysis, the separation efficiency of rare earth elements and impurities will be greatly reduced. This is because the chemical mechanisms of electrochemical hydrolysis precipitation and the presence of metal ions are fundamentally different. Simply rotating the electrodes without controlling the corresponding electrolysis conditions cannot effectively control the concentration of hydroxide ions on the electrode surface. This will not only greatly reduce the separation efficiency of rare earth elements and impurities, but also cause a large amount of dense precipitate to adhere to the electrodes, thereby increasing the cell voltage.

[0008] Current methods for obtaining rare earth enrichments generally involve introducing impurity ions and co-precipitating impurities, which reduces the separation effect between rare earths and impurities. Furthermore, due to poor mass transfer on the electrode surface, rare earths tend to deposit in large quantities on the electrode surface, causing a significant increase in cell voltage.

[0009] Therefore, there is an urgent need for a method to prepare rare earth enrichments that is simple to operate, requires no chemical reagents, is environmentally friendly, and can alleviate problems such as impurity co-precipitation and electrode scaling during the electrochemical enrichment process. Summary of the Invention

[0010] To address the aforementioned technical problems, the present invention aims to provide a method for preparing rare earth enrichments by cyclone electrolysis. The method described in this invention does not require the addition of chemical reagents, is environmentally friendly, and alleviates problems such as easy co-precipitation of impurities and electrode scaling during the electrochemical enrichment process.

[0011] To achieve this objective, the present invention adopts the following technical solution:

[0012] This invention provides a method for preparing rare earth enrichments by cyclone electrolysis, the method comprising the following steps:

[0013] The rare earth ion solution in the cathode region is subjected to cyclone electrolysis using an electrolytic cell. During the cyclone electrolysis process, the cathode rotates continuously along its central axis. After the cyclone electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain rare earth enrichment.

[0014] The main principle of traditional electrochemical methods for preparing enriched substances is to utilize the hydroxide ions generated by the hydrogen evolution reaction on the cathode surface to combine with metal ions in the solution to produce hydroxide precipitates, thereby achieving the separation and enrichment of metal ions from the solution.

[0015] However, due to the limited mass transfer between the electrode surface and the bulk solution, a large number of hydroxide ions cannot diffuse into the solution in time or react fully with rare earth ions in the solution. This ultimately leads to an abnormal increase in pH at the electrode interface, causing other impurities to co-precipitate with rare earth ions, reducing current efficiency and the grade of the enriched product. This phenomenon is more severe at high current densities, limiting further increases in the rare earth precipitation rate and significantly extending production time. Furthermore, when mass transfer is poor, deposits are more likely to grow firmly on the electrode surface, hindering electron transfer in the water electrolysis reaction and causing an increase in cell voltage. The main reason for this phenomenon is the mismatch between the generation or reaction rate of hydroxide ions and the mass transfer near the electrode.

[0016] This invention overcomes the problems of impurity co-precipitation and cell voltage rise caused by poor mass transfer on the electrode surface in traditional electrolytic enrichment methods. This invention uses a rotating cathode, which continuously rotates to enhance the mass transfer process of the products generated on the electrode surface in situ, greatly reducing impurity co-precipitation and electrode scale, enhancing the separation efficiency of rare earth and impurities, facilitating the effective use of electrical energy, and effectively suppressing the increase of cell voltage, thereby greatly improving the grade of rare earth enriched products prepared by electrolysis.

[0017] The "grade of rare earth enrichment" mentioned in this invention refers to the percentage by mass of the total amount of rare earth (calculated as rare earth oxides) in the rare earth-containing solid precipitate obtained by electrolysis. A higher grade of rare earth enrichment indicates a higher recovery enrichment rate and a lower impurity content in the obtained rare earth enrichment.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0019] Preferably, the rotation speed is 50rpm-800rpm, for example, it can be 50rpm, 100rpm, 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, 700rpm or 800rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0020] In this invention, the rotation speed of the cathode is further controlled to be 50 rpm-800 rpm, which can better enhance the diffusion process of hydroxide ions from the electrode surface to the bulk solution. This method is used when the pH of impurity hydrolysis is close to the pH at which rare earth elements are deposited. Increasing the rotation speed will result in a better separation effect. If the rotation speed is too low, the effect of improving hydroxide ion diffusion and enhancing mass transfer on the electrode surface will not be obvious. If the rotation speed is too high, it will not only fail to further improve the separation effect, but will also increase energy consumption.

[0021] Preferably, the ratio of the cathode liquid volume to the effective cathode area is (5-12):1, for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1 or 12:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the current density of the swirl electrolysis is 3 A / m. 2 -200A / m 2 For example, it could be 3A / m 2 10A / m 2 20A / m 2 30A / m 2 40A / m 2 50A / m 2 60A / m 2 70A / m 2 80A / m 2 90A / m 2 100A / m 2 110A / m 2 120A / m 2 130A / m 2 140A / m 2 150A / m 2 160A / m 2 170A / m 2 180A / m 2 190A / m 2 Or 200A / m 2 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0023] This invention further controls the current density of swirl electrolysis to 3 A / m 2 -200A / m 2 The current density is one of the important factors to ensure the separation effect. When the pH of impurity hydrolysis is close to the pH of rare earth deposition, the current density is reduced to achieve better separation effect. When the current density is too high, a large number of hydroxide ions will be generated in the catholyte instantly, causing the pH near the electrode to rise suddenly. Even cyclone electrolysis cannot eliminate the strongly alkaline area near the cathode electrode in this case, which can easily cause impurities to co-precipitate and scale to form on the electrode. On the other hand, if the current density is too low, it will directly affect the electrolysis efficiency.

[0024] Preferably, the cathode comprises an inert cathode or a transition metal cathode, and is preferably a titanium cathode, a stainless steel cathode, or a nickel cathode.

[0025] Preferably, the anode in the electrolytic cell includes an inert anode or a transition metal anode, and is preferably a titanium-based coated anode or a graphite anode.

[0026] Preferably, the anolyte comprises any one or a combination of at least two of hydrochloric acid solution, nitric acid solution, ammonium chloride solution or magnesium sulfate solution. Typical but non-limiting combinations include combinations of hydrochloric acid solution and nitric acid solution, combinations of nitric acid solution and ammonium chloride solution, combinations of ammonium chloride solution and magnesium sulfate, combinations of nitric acid solution, ammonium chloride solution and magnesium sulfate, and combinations of hydrochloric acid solution, ammonium chloride solution and magnesium sulfate.

[0027] Preferably, the cathode liquid and the anolyte in the electrolytic cell are separated by an anion exchange membrane.

[0028] Preferably, the anion exchange membrane includes a quaternary ammonium salt type, a guanidine type anion exchange membrane, or an imidazole type anion exchange membrane.

[0029] Preferably, the rare earth ion concentration in the rare earth ion solution is 50 mg / L to 10000 mg / L, for example, it can be 50 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, 500 mg / L, 600 mg / L, 700 mg / L, 800 mg / L, 900 mg / L, 1000 mg / L, 2000 mg / L, 3000 mg / L, 4000 mg / L, 5000 mg / L, 6000 mg / L, 7000 mg / L, 8000 mg / L, 9000 mg / L or 10000 mg / L, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0030] The rare earth ion solution in this invention can be a single rare earth or a mixed rare earth solution, wherein the impurity ions contained therein include, but are not limited to, Mg. 2+ Ca 2+ ,Th 4+ UO 2+ Cu 2+ Fe 2+ Fe 3+ Be 2+ Mn 2+ Al 3+ and / or Zn 2+ The concentration of the impurity ions is 1-100000 mg / L.

[0031] Preferably, the endpoint of the cyclone electrolysis is when the pH of the catholyte is 6.5-9.5, for example, it can be 6.5, 7, 7.5, 8, 8.5, 9 or 9.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] This invention achieves the precipitation of different rare earth ions by controlling the pH of the cathode solution to 6.5-9.5 at the endpoint of cyclone electrolysis, thus ensuring the enrichment effect of single or mixed rare earth ion solutions.

[0033] Preferably, the grade of the rare earth enrichment obtained by the method is 60-95%, for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94% or 95%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] As a preferred embodiment of the preparation method of the present invention, the preparation method includes the following steps:

[0035] An electrolytic cell is formed by a cathode solution, a cathode solution continuously rotating along a central axis at a speed of 50 rpm to 800 rpm, an anolyte solution, and an anode. The cathode solution and the anolyte solution are separated by an anion exchange membrane. The current density is 3 A / m. 2 -200A / m 2 The mixture is subjected to cyclone electrolysis, the endpoint of which is when the pH of the catholy solution is 6.5-9.5. After the electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain rare earth enrichment.

[0036] The cathode solution is a rare earth ion solution with a rare earth ion concentration of 50 mg / L to 10000 mg / L; the anode in the electrolytic cell is a titanium-based coated anode or a graphite anode; the anolyte in the electrolytic cell includes any one or a combination of at least two of hydrochloric acid solution, nitric acid solution, ammonium chloride solution or magnesium sulfate solution.

[0037] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] This invention overcomes the problems of impurity co-precipitation and cell voltage rise caused by poor mass transfer on the electrode surface in traditional electrolytic enrichment methods. This invention uses a rotating cathode, which continuously rotates to enhance the mass transfer process on the electrode surface in situ, greatly reducing impurity co-precipitation and electrode scale buildup, enhancing the separation efficiency of rare earth elements and impurities, facilitating the effective use of electrical energy, and effectively suppressing cell voltage growth, thereby greatly improving the grade of rare earth enriched products prepared by electrolysis. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the electrolytic cell described in Embodiment 1 of the present invention. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0042] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used are conventional methods and techniques in the art.

[0043] Example 1

[0044] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis, the method comprising the following steps:

[0045] like Figure 1 The electrolytic cell structure shown is as follows: 1 represents the catholyte, 2 represents the cathode rotating along the central axis, 3 represents the anion exchange membrane, 4 represents the anode, and 5 represents the anolyte. In this embodiment, a single rare earth nitrate solution with a dysprosium ion concentration of 50 mg / L, a calcium ion concentration of 100,000 mg / L, a magnesium ion concentration of 980 mg / L, and a zinc ion concentration of 40 mg / L is used as the catholyte; a rotating Ti electrode rotating at 300 rpm is used as the cathode; a 0.1 mol / L magnesium nitrate solution is used as the anolyte; and a titanium-plated ruthenium electrode is used as the anode. The ratio of the catholyte volume to the effective cathode area is 8:1. The catholyte and the anolyte are separated by a quaternary ammonium salt anion exchange membrane. The current density is 100 A / m². 2 The mixture is subjected to cyclone electrolysis, the endpoint of which is when the pH of the catholy solution is 7. After the electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain rare earth enrichment containing dysprosium.

[0046] Example 2

[0047] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis, the method comprising the following steps:

[0048] The sample contained lanthanum (143.7 mg / L), cerium (5.1 mg / L), praseodymium (32.3 mg / L), neodymium (120.8 mg / L), samarium (22.3 mg / L), europium (3.4 mg / L), gadolinium (18.3 mg / L), terbium (2.6 mg / L), dysprosium (13.8 mg / L), holmium (2.0 mg / L), erbium (5.6 mg / L), thulium (0.3 mg / L), and yttrium (74.1 mg / L), with a total rare earth concentration of 444 mg / L. The impurity ions were thorium, magnesium, calcium, and aluminum, with concentrations of [missing information]. An electrolytic cell was constructed using a mixed rare earth chloride solution with concentrations of 1 mg / L, 1443 mg / L, 273 mg / L, and 29.8 mg / L as the catholyte, Ti metal rotating at 50 rpm as the cathode, 0.1 mol / L hydrochloric acid solution as the anolyte, and a titanium-based ruthenium-iridium oxide coated electrode as the anode. The ratio of the catholyte volume to the effective cathode area was 5:1. The catholyte and anolyte were separated by a guanidine salt-type anion exchange membrane. The current density was 3 A / m³. 2 The mixture is subjected to cyclone electrolysis, the endpoint of which is when the pH of the catholyte is 9. After electrolysis, the product obtained in the cathode region is subjected to solid-liquid separation to obtain a rare earth enrichment containing lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium and yttrium, with a grade of [grade missing].

[0049] Example 3

[0050] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis, the method comprising the following steps:

[0051] An electrolytic cell was constructed using a single rare earth chloride solution containing 10,000 mg / L lanthanum ions and 300 mg / L calcium impurity ions as the catholyte, a stainless steel electrode rotating at 800 rpm as the cathode, a 0.1 mol / L ammonium chloride solution as the anolyte, and Fe metal as the anode. The ratio of the catholyte volume to the effective cathode area was 11:1. The catholyte and anolyte were separated by a quaternary ammonium salt anion exchange membrane. The electrolytic cell was operated at a current density of 200 A / m². 2 The mixture is subjected to cyclone electrolysis, the endpoint of which is when the pH of the catholy solution is 9.5. After the electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain a rare earth enrichment containing lanthanum.

[0052] Example 4

[0053] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis. The only difference from Embodiment 1 is that the rotation speed of the Ti electrode is 30 rpm.

[0054] Example 5

[0055] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis. The only difference from Embodiment 1 is that the current density during cyclone electrolysis is 600 A / m. 2 .

[0056] Example 6

[0057] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis. The only difference from Embodiment 1 is that the ratio of the cathode liquid volume to the effective cathode area is 3:1.

[0058] Example 7

[0059] This embodiment provides a method for preparing rare earth enrichments by cyclone electrolysis. The only difference from Embodiment 1 is that the ratio of the cathode liquid volume to the effective cathode area is 15:1.

[0060] Comparative Example 1

[0061] This comparative example provides a method for preparing rare earth enrichments by electrolysis. The only difference from Example 1 is that the rotation speed of the Ti electrode is 0, while the rest of the operation remains the same.

[0062] Comparative Example 2

[0063] This comparative example provides a method for preparing rare earth enrichments by electrolysis. The only difference from Example 1 is that the rotation speed of the Ti electrode is 0, and electrolysis is carried out at a stirring speed of 300 rpm using conventional mechanical stirring. All other operations remain the same.

[0064] Test method: The grade of rare earth enrichment in the obtained rare earth enrichment was determined by instrumental analysis method according to the method of XB / T 632-2023.

[0065] Table 1

[0066] Grade of rare earth enrichment (in REO) / % Example 1 78 Example 2 89 Example 3 92 Example 4 48 Example 5 49 Example 6 61 Example 7 67 Comparative Example 1 11 Comparative Example 2 59

[0067] The test results show that:

[0068] (1) As can be seen from Examples 1-3, the present invention uses a rotating cathode, which continuously rotates to enhance the mass transfer process on the electrode surface in situ, greatly reducing the co-precipitation of impurities and electrode scaling, enhancing the separation efficiency of rare earth and impurities, which is conducive to the effective use of electrical energy and can effectively suppress the growth of cell voltage, thereby greatly improving the grade of rare earth enrichment prepared by electrolysis.

[0069] (2) A comparison of Examples 1 and 4-5 shows that further controlling the cathode rotation speed to 50 rpm-800 rpm in this invention can better promote the diffusion of hydroxide ions generated in situ on the electrode surface and suppress the formation of strong alkaline regions on the electrode surface. If the rotation speed is too low, the effect of enhancing hydroxide ion diffusion is not obvious, which will lead to the formation of a large number of strong alkaline regions on the electrode surface, causing impurities to co-precipitate. If the rotation speed is too high, the energy consumption will be high. Simultaneously, the current density of the cyclone electrolysis is controlled at 3 A / m. 2 -200A / m2 Current density is one of the important factors to ensure separation effect. When the current density is too high, a large number of hydroxide ions will be generated in the catholyte instantly, causing the pH of the solution to rise suddenly. Even cyclone electrolysis cannot eliminate the strongly alkaline area near the cathode electrode in this case, which is very easy to cause co-precipitation of impurities and scale on the electrode. When the current density is too low, it will directly affect the electrolysis efficiency.

[0070] (3) By comparing Example 1 with Examples 6-7, it can be seen that the present invention further controls the ratio of cathode liquid volume to cathode effective area to (5-12):1, so as to improve the separation effect to the maximum efficiency.

[0071] (4) As can be seen from Example 1 and Comparative Examples 1-2, when a rotating cathode is not used or only mechanical stirring is used during the electrolysis process, it is impossible to enhance the mass transfer process on the electrode surface, which easily causes co-precipitation of impurities and electrode scaling, and cannot achieve the effect of enhancing the separation efficiency of rare earth and impurities.

[0072] In summary, this invention employs a rotating cathode, which continuously rotates to enhance the mass transfer process on the electrode surface in situ. This significantly reduces the co-precipitation of impurities and electrode scaling, thereby improving the separation efficiency of rare earth elements from impurities. It also facilitates the efficient utilization of electrical energy and effectively suppresses the increase in cell voltage. This overcomes the problems of impurity co-precipitation and cell voltage rise caused by poor mass transfer on the electrode surface in traditional electrolytic enrichment methods, thus greatly improving the grade of rare earth enriched products prepared by electrolysis.

[0073] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing rare earth enrichments by cyclone electrolysis, characterized in that, The method includes the following steps: The rare earth ion solution in the cathode region is subjected to cyclone electrolysis using an electrolytic cell. During the cyclone electrolysis process, the cathode rotates continuously along its central axis. After the cyclone electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain rare earth enrichment.

2. The method according to claim 1, characterized in that, The rotational speed is 50 rpm to 800 rpm; Preferably, the ratio of the cathode liquid volume to the effective cathode area is (5-12):

1.

3. The method according to claim 1 or 2, characterized in that, The current density of the swirl electrolysis is 3 A / m. 2 -200A / m 2 .

4. The method according to any one of claims 1-3, characterized in that, The cathode includes an inert cathode or a transition metal cathode, preferably a titanium cathode, a stainless steel cathode, or a nickel cathode.

5. The method according to any one of claims 1-4, characterized in that, The anode in the electrolytic cell includes an inert anode or a transition metal anode, preferably a titanium-based coated anode or a graphite anode; Preferably, the anolyte in the electrolytic cell includes any one or a combination of at least two of hydrochloric acid solution, nitric acid solution, ammonium chloride solution, or magnesium sulfate solution.

6. The method according to any one of claims 1-5, characterized in that, The cathode liquid and anolyte in the electrolytic cell are separated by an anion exchange membrane; Preferably, the anion exchange membrane comprises a quaternary ammonium salt type, a guanidine type, or an imidazole type anion exchange membrane.

7. The method according to any one of claims 1-6, characterized in that, The rare earth ion concentration in the rare earth ion solution is 50 mg / L-10000 mg / L.

8. The method according to any one of claims 1-7, characterized in that, The endpoint of the cyclone electrolysis is when the pH of the catholyte is 6.5-9.

5.

9. The method according to any one of claims 1-8, characterized in that, The rare earth enrichment prepared by the method has a grade of 60-95%.

10. The method according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: An electrolytic cell is formed by a cathode solution, a cathode solution continuously rotating along a central axis at a speed of 50 rpm to 800 rpm, an anolyte solution, and an anode. The cathode solution and the anolyte solution are separated by an anion exchange membrane. The current density is 3 A / m. 2 -200A / m 2 The mixture is subjected to cyclone electrolysis, the endpoint of which is when the pH of the catholy solution is 6.5-9.

5. After the electrolysis is completed, the product obtained in the cathode region is subjected to solid-liquid separation to obtain rare earth enrichment. The cathode solution is a rare earth ion solution with a rare earth ion concentration of 50 mg / L to 10000 mg / L; the anode includes a titanium-based coated anode or a graphite anode; the anolyte includes any one or a combination of at least two of hydrochloric acid solution, nitric acid solution, ammonium chloride solution or magnesium sulfate solution.

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