Method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnet

Abstract

The invention discloses a method for separating and purifying neodymium and dysprosium from a waste neodymium-iron-boron permanent magnet, and particularly relates to the field of resource recovery. A solid adsorbent is a zinc-based organic metal framework adsorbent (Zn-MOF), and the Zn-MOF solid adsorbent is prepared by taking zinc nitrate hexahydrate (Zn (NO3) 26H2O) and terephthalic acid (H2BDC) as raw materials, N, N-dimethylformamide (DMF) as a solvent and triethylamine (TEA) as an initiator through a normal-temperature stirring method. The synthesized Zn-MOF is used for primarily adsorbing and purifying neodymium and dysprosium in a waste neodymium-iron-boron simulation solution; and finally, the sintered Zn-MOF is used for secondarily adsorbing a desorption solution, so that the purpose of separating neodymium and dysprosium is achieved. According to the technical scheme, the problem that the neodymium and dysprosium extraction efficiency is affected due to the fact that the waste neodymium-iron-boron magnet leachate contains impurities is solved, and the neodymium and dysprosium extraction efficiency and purity are improved.

Description

Technical Field

[0001] The invention relates to the field of resource recovery, and in particular to a method for separating and purifying neodymium and dysprosium from discarded neodymium iron boron permanent magnets. Background Art

[0002] Neodymium, dysprosium and its compounds are key functional raw materials indispensable for the development of strategic emerging industries such as new energy, electronic information and national defense science and technology industries. Neodymium is the most powerful permanent magnetic material discovered so far. It is widely used in microphones, professional speakers, headphones, computer hard drives, motors and generators. Dysprosium is a key alloying element in neodymium iron boron permanent magnets. In recent years, global demand for dysprosium will surge, especially in the fields of green energy and electric vehicles.

[0003] At present, the content of rare earth elements in waste NdFeB magnets is about 30%, which is much higher than that in ore. The waste NdFeB magnet leaching solution often contains impurities such as cobalt, praseodymium, manganese, nickel, iron, and aluminum. The above impurities will have an adverse effect on the extraction of Nd and Dy and the electrolysis of high-purity metal Nd and Dy. In particular, cobalt will reduce the efficiency and metal purity of electrolysis of Nd and Dy. Therefore, there is an urgent need for a separation and purification method that can avoid the influence of impurities on the extraction efficiency and purity of Nd and Dy. Summary of the invention

[0004] The present invention aims to provide a method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, thereby solving the problem that the extraction efficiency of neodymium and dysprosium is affected by impurities in the waste neodymium iron boron magnet leaching solution.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: Using zinc nitrate hexahydrate and terephthalic acid as raw materials, N,N-dimethylformamide as solvent, and triethylamine as initiator, a Zn-MOF solid adsorbent was prepared by a room temperature stirring method; S2. Preparation of simulated solution: prepare the NdFeB simulated solution according to the ratio of each element in the NdFeB leaching solution, and adjust the pH value of the simulated solution to 4-6; S3, Zn-MOF adsorbent adsorption: using the Zn-MOF adsorbent prepared in step S1 to adsorb and separate neodymium and dysprosium from the simulated liquid in the weak acid system in step S2; S4, preparation of a separation agent: placing the Zn-MOF prepared in step S1 into a muffle furnace and calcining it to obtain a separation agent having selective adsorption for dysprosium; S5, desorbing with a desorbent: desorbing the Zn-MOF adsorbent after adsorption in step S3 with a desorbent; S6. Separation and purification: The Nd:D: solution desorbed in step S5 is subjected to adsorption separation and purification of Nd:D: with the separation agent prepared in step S4.

[0006] Furthermore, in step S1, carboxyl groups are attached to the mesopores or the surface of the Zn-MOF.

[0007] Furthermore, the carboxyl group of the Zn-MOF is connected to the benzene ring, and cooperates with the zinc ions to selectively adsorb the Nd and Dy ions, so that the Zn-MOF can adsorb, separate and purify Nd and Dy ions.

[0008] Furthermore, the preparation method of step S1 is as follows: it is carried out on a magnetic stirrer. First, a beaker containing dissolved zinc nitrate and terephthalic acid is placed on the magnetic stirrer, the rotation speed is set to 800 r / min, the temperature is room temperature, and then TEA solution is slowly added dropwise during the rotation. The TEA initiator dissociates the hydrogen ions of H2BDC, and the zinc ions and terephthalic acid undergo an organic synthesis reaction. The synthesis time is 4 hours. After filtering, it is washed with dichloromethane and vacuum dried for 12 hours to prepare a Zn-MOF adsorbent.

[0009] Furthermore, the contents of N, C, O, H and Zn in the Zn-MOF adsorbent prepared in step S1 are 4.01%, 48.53%, 28.11%, 6.59% and 12.76%, respectively, and the Zn-MOF adsorbent is a porous material with an average pore size of 56 nm.

[0010] Furthermore, the elements in the simulated liquid of step S2 are neodymium, dysprosium, cobalt, praseodymium, manganese and nickel, which account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% respectively.

[0011] Furthermore, in step S3, the Zn-MOF adsorbent adsorbs the NdFeB simulated liquid, with a solid-liquid ratio of 0.05 g / 20 mL, an adsorption temperature of 25° C., and an adsorption time of 180 s.

[0012] Furthermore, in step S5, the desorbent is any one of dilute hydrochloric acid, sulfuric acid and nitric acid with a concentration of 0.1 to 1 mol / L, the temperature is 25° C., and the desorption time is 180 s.

[0013] Furthermore, in step S6, the desorption solution obtained in step S5 is adjusted using the separation agent prepared in step S4, and the pH value can be adjusted in the range of 4 to 6, so that neodymium and dysprosium can be separated and purified.

[0014] Compared with the prior art, this solution has the following beneficial effects: 1. The adsorbent prepared by this scheme has good selectivity and fast adsorption speed, and can obtain high-purity Nd and Dy raw materials with very little impurity content. The purity of Nd and Dy can be improved by obtaining a second adsorbent by sintering MOF materials. The synthetic raw materials are cheap, the synthesis method is simple and convenient, and the synthesis cycle is short, which provides technical support for the preparation of high-purity Nd and Dy oxide or electrolytic high-purity metal Nd and Dy. At the same time, it also realizes the efficient recovery and purification of Nd and Dy from solutions rich in elements such as Nd, Dy, Cobalt, Aluminum, Iron, Manganese, Nickel, and Praseodymium, and the separation rate of Nd and Dy reaches 99.9%. This scheme has a high recovery and adsorption capacity, a fast adsorption rate of Nd and Dy, a high separation rate of Nd and Dy, and a high product purity.

[0015] 2. This solution directly extracts high-purity Nd and Dy from NdFeB simulated liquid through adsorption separation and desorption processes, realizes the separation of Nd and Dy from other impurity elements, especially greatly reduces the influence of cobalt, and prepares high-purity Nd and Dy products with a purity of up to 99.9%. The influence of cobalt on subsequent electrolysis of high-purity metals is strictly controlled, the content of impurity elements is greatly reduced, the purity of Nd and Dy is improved overall, and the content of other impurities in the electrolysis process is effectively reduced, providing technical support for the electrolysis of high-purity metal Nd and Dy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a process flow chart of a method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to Example 1; Figure 2 is a selective adsorption distribution ratio diagram of the Zn-MOF adsorbent in Example 1; Figure 3 This is a diagram showing the effect of the type of desorbent in Example 1 on the desorption of neodymium and dysprosium by the Zn-MOF adsorbent; Figure 4 This is the XRD phase analysis diagram of Zn-MOF in Example 1. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below through specific embodiments: Example

[0018] A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, in this embodiment, the zinc-based organic metal framework is referred to as Zn-MOF, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: Dissolve 2.9749g zinc nitrate and 4.9839g terephthalic acid (H2BDC) in 240mL N,N-dimethylformamide (DMF) in a beaker, and place the beaker on a magnetic stirrer. The speed of the magnetic stirrer is set to 800r / min and the temperature is room temperature. Slowly add 20mL triethylamine (TEA) solution during the rotation. The TEA initiator dissociates the hydrogen ions of H2BDC, and the zinc ions react with terephthalic acid for an organic synthesis reaction. The synthesis time is 4h. After filtering, wash with dichloromethane and vacuum dry for 12h to prepare the Zn-MOF adsorbent. The contents of N, C, O, H, and Zn in the Zn-MOF adsorbent are 4.01%, 48.53%, 28.11%, 6.59%, and 12.76%, respectively. The XRD phase analysis diagram is as follows: Figure 3 As shown, it shows that Zn-MOF is 30 H 44 N2O2Zn has a similar structure to organic matter, and its chemical formula is C 40 H 66 N3O 18 Zn2, the adsorbent has carboxyl groups located on the surface and in the pores that work together with zinc ions to selectively adsorb neodymium and dysprosium, with an adsorption capacity of 180 mg / g.

[0019] S2. Preparation of simulated solution: prepare NdFeB simulated solution according to the proportions of 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% of neodymium, dysprosium, cobalt, praseodymium, manganese and nickel respectively, and adjust the solution pH to 4-6; S3, Zn-MOF adsorbent adsorption experiment: The Zn-MOF prepared in step S1 was used at room temperature to perform the first stage adsorption of NdFeB on the waste NdFeB leaching solution, with a solid-liquid ratio of 0.05g / 20mL, adsorption temperature: 25°C, adsorption time 180s, and a high adsorption capacity of up to 256mg / g. The adsorption capacity of the adsorbent for each element is shown in the following table: Figure 2 As shown, when the pH is between 4 and 6, the adsorbent has the highest adsorption capacity for Nd:Dy, and has a very high distribution ratio for the adsorption of Nd:Dy, Co:Pr, and has good selective adsorption performance.

[0020] S4. Preparation of separating agent: The Zn-MOF prepared in step S1 is placed in a muffle furnace and calcined at 750° C. for 3 h. The separating agent is a specific zinc oxide formed after the Zn-MOF is oxidized in the air, and has selective adsorption for dysprosium, indicating that this adsorbent has practical significance for the separation and purification of ions in waste NdFeB leachate.

[0021] S5. Desorption experiment: The desorbents selected were hydrochloric acid, nitric acid, sulfuric acid, citric acid, tartaric acid, malic acid, etc., with a liquid-to-solid ratio of 0.05 g / 20 mL and an acid concentration of 0.05-0.1 mol / L. The desorption was carried out at room temperature. The desorption effect was good and the desorption rate could reach 100%. Figure 3 As shown, the desorption effect with 0.1 mol / L hydrochloric acid is the most ideal, and no additional reagents are needed.

[0022] S6, separation and purification: the Nd and Dy solution desorbed in step S5 is subjected to Nd and Dy separation using the separation agent prepared in step S4, and the pH is adjusted to 4 to 6. After separation, a Nd and Dy ion solution with Nd and Dy completely separated can be obtained. Example

[0023] A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, in this embodiment, the zinc-based organic metal framework is referred to as Zn-MOF, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: 5.9498 g zinc nitrate and 4.9839 g terephthalic acid were dissolved in 240 mL DMF in a beaker, and the beaker was placed on a magnetic stirrer with a speed of 800 r / min and room temperature. 20 mL of TEA solution was slowly added during the rotation. The TEA initiator dissociated the hydrogen ions of H2BDC, and the zinc ions reacted with terephthalic acid for an organic synthesis reaction. The synthesis time was 4 h. After filtering, the mixture was washed with dichloromethane and vacuum dried for 12 h to prepare a Zn-MOF adsorbent with an adsorption capacity of 176 mg / g.

[0024] S2. Preparation of simulated solution: prepare NdFeB simulated solution according to the proportions of 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% of neodymium, dysprosium, cobalt, praseodymium, manganese and nickel respectively, and adjust the solution pH to 4-6; S3. Zn-MOF adsorbent adsorption experiment: The Zn-MOF prepared in step S1 was used to perform the first stage adsorption of Nd2Dysprosium on the waste NdFeB leaching solution at room temperature. The solid-liquid ratio was 0.05 g / 20 mL, the adsorption temperature was 25 ° C, and the adsorption time was 180 s. The adsorption capacity of the adsorbent for each element was as follows: Figure 2 When the pH is between 4 and 6, the adsorbent has a very high distribution ratio for Nd and Dy, and has a very good selective adsorption performance.

[0025] S4. Preparation of a separation agent: The Zn-MOF prepared in step S1 is placed in a muffle furnace and calcined at 750° C. for 3 h to obtain a separation agent having selective adsorption for dysprosium.

[0026] S5. Desorption experiment: Desorbents include hydrochloric acid, nitric acid, sulfuric acid, citric acid, tartaric acid, malic acid, etc., with a liquid-to-solid ratio of 0.05 g / 20 mL and an acid concentration of 0.05 to 0.1 mol / L at room temperature. Figure 3 As shown, the desorption effect with 0.1 mol / L hydrochloric acid is the most ideal, and no additional reagents are needed.

[0027] S6, separation and purification: the Nd and Dy solution desorbed in step S5 is subjected to Nd and Dy separation using the separation agent prepared in step S4, and the pH is adjusted to 4 to 6. After separation, a Nd and Dy ion solution with Nd and Dy completely separated can be obtained. Example

[0028] A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, in this embodiment, the zinc-based organic metal framework is referred to as Zn-MOF, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: 8.9247 g zinc nitrate and 4.9839 g terephthalic acid were dissolved in 240 mL DMF in a beaker, and the beaker was placed on a magnetic stirrer with a speed of 800 r / min and room temperature. Then, 20 mL of TEA solution was slowly added dropwise during the rotation. The TEA initiator dissociated the hydrogen ions of H2BDC, and the zinc ions reacted with terephthalic acid for an organic synthesis reaction. The synthesis time was 4 h. After filtering, the mixture was washed with dichloromethane and vacuum dried for 12 h to prepare a Zn-MOF adsorbent with an adsorption capacity of 153 mg / g.

[0029] S2. Preparation of simulated solution: prepare NdFeB simulated solution according to the proportions of 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% of neodymium, dysprosium, cobalt, praseodymium, manganese and nickel respectively, and adjust the solution pH to 4-6; S3. Zn-MOF adsorbent adsorption experiment: The Zn-MOF prepared in step S1 was used at room temperature to perform the first-stage adsorption of Nd2Dysprosium on the waste NdFeB leaching solution. The solid-liquid ratio was 0.05 g / 20 mL, the adsorption temperature was 25 ° C, and the adsorption time was 180 s. The adsorption capacity of the adsorbent for each element was as follows: Figure 2 When the pH is between 4 and 6, the adsorbent has a very high distribution ratio for Nd and Dy, and has a very good selective adsorption performance.

[0030] S4. Preparation of a separation agent: The Zn-MOF prepared in step S1 is placed in a muffle furnace and calcined at 750° C. for 3 h to obtain a separation agent having selective adsorption for dysprosium.

[0031] S5. Desorption experiment: Desorbents include hydrochloric acid, nitric acid, sulfuric acid, citric acid, tartaric acid, malic acid, etc., with a liquid-to-solid ratio of 0.05 g / 20 mL and an acid concentration of 0.05 to 0.1 mol / L at room temperature. Figure 3 As shown, the desorption effect with 0.1 mol / L hydrochloric acid is the most ideal, and no additional reagents are needed.

[0032] S6, separation and purification: the Nd and Dy solution desorbed in step S5 is subjected to Nd and Dy separation using the separation agent prepared in step S4, and the pH is adjusted to 4 to 6. After separation, a Nd and Dy ion solution with Nd and Dy completely separated can be obtained. Example

[0033] A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, in this embodiment, the zinc-based organic metal framework is referred to as Zn-MOF, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: 14.8745 g zinc nitrate and 4.9839 g terephthalic acid were dissolved in 240 mL DMF in a beaker, and the beaker was placed on a magnetic stirrer with a speed of 800 r / min and room temperature. Then, 20 mL of TEA solution was slowly added dropwise during the rotation. The TEA initiator dissociated the hydrogen ions of H2BDC, and the zinc ions reacted with terephthalic acid for an organic synthesis reaction. The synthesis time was 4 h. After filtering, the mixture was washed with dichloromethane and vacuum dried for 12 h to prepare a Zn-MOF adsorbent with an adsorption capacity of 105 mg / g.

[0034] S2. Preparation of simulated solution: prepare NdFeB simulated solution according to the proportions of 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% of neodymium, dysprosium, cobalt, praseodymium, manganese and nickel respectively, and adjust the solution pH to 4-6; S3. Zn-MOF adsorbent adsorption experiment: The Zn-MOF prepared in step S1 was used at room temperature to perform the first-stage adsorption of Nd2Dysprosium on the waste NdFeB leaching solution. The solid-liquid ratio was 0.05 g / 20 mL, the adsorption temperature was 25 ° C, and the adsorption time was 180 s. The adsorption capacity of the adsorbent for each element was as follows: Figure 2 When the pH is between 4 and 6, the adsorbent has a very high distribution ratio for Nd and Dy, and has a very good selective adsorption performance.

[0035] S4. Preparation of a separation agent: The Zn-MOF prepared in step S1 is placed in a muffle furnace and calcined at 750° C. for 3 h to obtain a separation agent having selective adsorption for dysprosium.

[0036] S5. Desorption experiment: Desorbents include hydrochloric acid, nitric acid, sulfuric acid, citric acid, tartaric acid, malic acid, etc., with a liquid-to-solid ratio of 0.05 g / 20 mL and an acid concentration of 0.05 to 0.1 mol / L at room temperature. Figure 3 As shown, the desorption effect with 0.1 mol / L hydrochloric acid is the most ideal, and no additional reagents are needed.

[0037] S6, separation and purification: the Nd and Dy solution desorbed in step S5 is subjected to Nd and Dy separation using the separation agent prepared in step S4, and the pH is adjusted to 4 to 6. After separation, a Nd and Dy ion solution with Nd and Dy completely separated can be obtained. Example

[0038] A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, in this embodiment, the zinc-based organic metal framework is referred to as Zn-MOF, comprising the following steps: S1. Preparation of Zn-MOF adsorbent: 17.8494g zinc nitrate and 4.9839g terephthalic acid were dissolved in 240mL DMF in a beaker, and the beaker was placed on a magnetic stirrer. The speed of the magnetic stirrer was set to 800 r / min and the temperature was room temperature. Then, 20mL TEA solution was slowly added dropwise during the rotation. The TEA initiator dissociated the hydrogen ions of H2BDC, and the zinc ions and terephthalic acid underwent organic synthesis reaction. The synthesis time was 4h. After filtering, the Zn-MOF adsorbent was washed with dichloromethane and vacuum dried for 12h. The adsorption capacity was 67mg / g.

[0039] S2. Preparation of simulated solution: prepare NdFeB simulated solution according to the proportions of 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% of neodymium, dysprosium, cobalt, praseodymium, manganese and nickel respectively, and adjust the solution pH to 4-6; S3. Zn-MOF adsorbent adsorption experiment: The Zn-MOF prepared in step S1 was used at room temperature to perform the first-stage adsorption of Nd2Dysprosium on the waste NdFeB leaching solution. The solid-liquid ratio was 0.05 g / 20 mL, the adsorption temperature was 25 ° C, and the adsorption time was 180 s. The adsorption capacity of the adsorbent for each element was as follows: Figure 2 When the pH is between 4 and 6, the adsorbent has a very high distribution ratio for Nd and Dy, and has a very good selective adsorption performance.

[0040] S4. Preparation of a separation agent: The Zn-MOF prepared in step S1 is placed in a muffle furnace and calcined at 750° C. for 3 h to obtain a separation agent having selective adsorption for dysprosium.

[0041] S5. Desorption experiment: Desorbents include hydrochloric acid, nitric acid, sulfuric acid, citric acid, tartaric acid, malic acid, etc., with a liquid-to-solid ratio of 0.05 g / 20 mL and an acid concentration of 0.05 to 0.1 mol / L at room temperature. Figure 3 As shown, the desorption effect with 0.1 mol / L hydrochloric acid is the most ideal, and no additional reagents are needed.

[0042] S6, separation and purification: the Nd and Dy solution desorbed in step S5 is subjected to Nd and Dy separation using the separation agent prepared in step S4, and the pH is adjusted to 4 to 6. After separation, a Nd and Dy ion solution with Nd and Dy completely separated can be obtained.

[0043] The above are only embodiments of the present invention, and the common knowledge such as the known specific structures and / or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets, characterized in that: The steps include: S1. Preparation of Zn-MOF adsorbent: Using zinc nitrate hexahydrate and terephthalic acid as raw materials, N,N-dimethylformamide as solvent, and triethylamine as initiator, a Zn-MOF solid adsorbent was prepared by a room temperature stirring method; S2. Preparation of simulated solution: prepare the simulated solution of NdFeB according to the ratio of each element in the NdFeB leaching solution, and adjust the pH value of the simulated solution to 4-6; S3, Zn-MOF adsorbent adsorption: using the Zn-MOF adsorbent prepared in step S1 to adsorb and separate neodymium and dysprosium from the simulated liquid in the weak acid system in step S2; S4, preparation of a separation agent: placing the Zn-MOF prepared in step S1 into a muffle furnace and calcining it to obtain a separation agent having selective adsorption for dysprosium; S5, desorbing with a desorbent: desorbing the Zn-MOF adsorbent after adsorption in step S3 with a desorbent; S6. Separation and purification: The Nd:D: solution desorbed in step S5 is subjected to adsorption separation and purification of Nd:D: with the separation agent prepared in step S4.

2. The method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 1, characterized in that: In step S1, carboxyl groups are attached to the mesopores or the surface of the Zn-MOF.

3. A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 2, characterized in that: The carboxyl group of the Zn-MOF is connected to the benzene ring, and cooperates with the zinc ions to selectively adsorb the neodymium and dysprosium ions, so that the Zn-MOF can adsorb, separate and purify neodymium and dysprosium.

4. The method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 3, characterized in that: The preparation method of step S1 is as follows: it is carried out on a magnetic stirrer. First, a beaker containing dissolved zinc nitrate and terephthalic acid is placed on the magnetic stirrer, the rotation speed is set to 800 r / min, the temperature is room temperature, and then TEA solution is slowly added dropwise during the rotation. The TEA initiator dissociates the hydrogen ions of H2BDC, and the zinc ions and terephthalic acid undergo an organic synthesis reaction. The synthesis time is 4 hours. After filtering, it is washed with dichloromethane and vacuum dried for 12 hours to prepare a Zn-MOF adsorbent.

5. A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 1 or 4, characterized in that: The contents of N, C, O, H and Zn in the Zn-MOF adsorbent prepared in step S1 are 4.01%, 48.53%, 28.11%, 6.59% and 12.76% respectively. The Zn-MOF adsorbent is a porous material with an average pore size of 56 nm.

6. The method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 1, characterized in that: The elements in the simulated liquid of step S2 are neodymium, dysprosium, cobalt, praseodymium, manganese and nickel, which account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05% and 0.02% respectively.

7. A method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 6, characterized in that: In step S3, the Zn-MOF adsorbent adsorbs the NdFeB simulated liquid, with a solid-liquid ratio of 0.05 g / 20 mL, an adsorption temperature of 25° C., and an adsorption time of 180 s.

8. The method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 1, characterized in that: In step S5, the desorbent is any one of dilute hydrochloric acid, sulfuric acid and nitric acid with a concentration of 0.1 to 1 mol / L, the temperature is 25° C., and the desorption time is 180 s.

9. The method for separating and purifying neodymium and dysprosium from waste neodymium iron boron permanent magnets according to claim 1, characterized in that: In step S6, the desorption solution obtained in step S5 is adjusted using the separation agent prepared in step S4, and the pH value can be adjusted in the range of 4 to 6, so that neodymium and dysprosium are separated and purified.

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