Preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnet
The method uses P-D331 and ZnO-MOF to selectively separate and purify neodymium and dysprosium from waste magnets, overcoming impurity issues and achieving 99.99% purity, suitable for neodymium-iron-boron magnets.
Patent Information
- Application Number
- CN202510469419.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2025-07-15
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
When the prior art is separated and purified by neodymium dysprosium from waste neodymium iron boron permanent magnets, impurity elements such as cobalt affect electrolytic efficiency and purity, especially the existence of cobalt reduces the purity and electrolytic efficiency of neodymium dysprosium.
The method of combining phosphorylated epoxy anion exchange resin (P-D331) and multi-stage pore zinc oxide separation agent (ZnO-MOF) is adopted to selectively adsorb and separate neodymium dysprosium through adsorption and desorption processes. ZnO-MOF is prepared by topological conversion to improve selectivity, combining the multi-stage pore structure and selective adsorption of phosphate groups to achieve efficient separation of neodymium dysprosium.
The high-purity separation of neodymium dysprosium was achieved, the purification rate of dysprosium reached 99.99%, and the purification rate of neodymium reached 99.99%, effectively reducing the influence of impurities, especially cobalt, and improving the purity of the electrolytic high-purity metal neodymium dysprosium.
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Figure CN120311048A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of recycling of key rare earth resources, and particularly relates to a preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets. Background Art
[0002] Neodymium, dysprosium and their compounds are key functional raw materials indispensable for the development of strategic emerging industries such as new energy and electronic information, as well as national defense science and technology industries. Neodymium is the most powerful permanent magnet material discovered so far. It is widely used in microphones, professional speakers, headphones, computer hard disks, electric motors and generators, mainly in neodymium-iron-boron permanent magnets; dysprosium is a key alloying element in neodymium-iron-boron permanent magnets, and the global demand for dysprosium will surge in recent years, especially in the fields of green energy and electric vehicles.
[0003] At present, the content of rare earth elements in waste neodymium-iron-boron magnets is about 30%, which is much higher than that of ores. However, waste neodymium-iron-boron magnet leaching solutions often contain impurities such as cobalt, praseodymium, manganese, nickel, iron, and aluminum, which have an adverse effect on the extraction of neodymium and dysprosium and the electrolysis of high-purity neodymium and dysprosium metals. In particular, cobalt will reduce the efficiency and metal purity during the electrolysis of neodymium and dysprosium. Summary of the Invention
[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets. The adsorbent prepared by this method has good selectivity and fast adsorption rate, and can obtain high-purity neodymium and dysprosium raw materials with extremely low impurity content; the synthesis raw materials are cheap, the synthesis method is simple and convenient, and the synthesis period is short, providing technical support for the preparation of high-purity neodymium and dysprosium oxides or the electrolysis of high-purity neodymium and dysprosium metals.
[0005] The technical solution of the present invention is as follows: A preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets, characterized by comprising the following steps: (1) Preparation of solid adsorbent: Using an epoxy-based anion exchange resin (abbreviated as D331 hereinafter) as a carrier, phosphorylating it by rotary evaporation with tributyl phosphate (abbreviated as TBP hereinafter) to obtain a phosphorylated epoxy-based anion exchange resin (abbreviated as P-D331 hereinafter) solid adsorbent; (2) Adsorbing neodymium and dysprosium from waste neodymium-iron-boron simulated solution: Using the solid adsorbent prepared in step (1) to simultaneously adsorb and separate neodymium and dysprosium from the waste neodymium-iron-boron simulated solution, and simultaneously adsorbing neodymium and dysprosium into P-D331; (3) Preparation of hierarchical pore zinc oxide separating agent: Pyrolyzing the zinc oxide separating agent into a hierarchical pore zinc oxide separating agent (abbreviated as ZnO-MOF hereinafter) by using a topological transformation method; (4) Desorbing neodymium and dysprosium: Using a desorbent to desorb the P-D331 adsorbent after adsorbing neodymium and dysprosium in step (3) to obtain a desorbing solution containing neodymium and dysprosium; (5) Separation and purification: For the neodymium-dysprosium-containing solution after desorption in step (4), the zinc oxide separating agent prepared in step (3) is used for adsorption to separately separate and purify neodymium and dysprosium; this step is repeated 2 - 4 times to purify neodymium and dysprosium respectively.
[0006] Preferably, the mesopores or the surface of the solid adsorbent in step (1) are attached with phosphate groups, and the phosphate groups and the amino groups carried by D331 act together to selectively adsorb neodymium and dysprosium ions, so that P-D331 can adsorb, separate and purify neodymium and dysprosium.
[0007] Preferably, the preparation process of step (1) is carried out on a rotary evaporator. First, weigh the epoxy-based anion exchange resin (D331) in a container, then add a mixed solution of tributyl phosphate (TBP) and dichloromethane, set the rotation speed to 80 - 100 r / min, the temperature to room temperature, and carry out rotary evaporation under a vacuum pressure of 95 - 45 KPa. The pressure is reduced by 5 - 10 KPa every 25 - 35 min. When the pressure is 40 - 50 KPa, carry out rotary evaporation at a water bath temperature of 35 - 45 °C for 1 - 2 h to completely evaporate dichloromethane. The slow volatilization of dichloromethane brings tributyl phosphate (TBP) into the mesopores of the epoxy-based anion exchange resin (D331), and the phosphate groups are carried on the carrier of the epoxy-based anion exchange resin (D331). After rotary evaporation, the phosphate groups are stabilized by vacuum drying for 12 - 14 h, and finally washed with ultrapure water and ethanol, and then vacuum dried for 12 - 14 h to obtain the phosphorylated epoxy-based anion exchange resin (abbreviation, P-D331) adsorbent.
[0008] Preferably, in step (2), the P-D331 adsorbent adsorbs neodymium and dysprosium in neodymium iron boron, the solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 20 - 30 °C, and the adsorption time is 2 - 3 h; the adsorption capacity is high, reaching more than 100 mg / g. Compared with the unmodified D-331 resin, the adsorption capacity is increased by 60 mg / g, and the adsorption selectivity is increased by more than 4 times.
[0009] Preferably, in step (3), Zn-MOF is pyrolyzed under gradient temperature control (25 - 750 °C) in a muffle furnace. Using its oxygen vacancy concentration gradient and lattice distortion effect, gradient temperature control can control the crystal growth rate and make it form a more perfect crystal structure, and ZnO-MOF with selective adsorption for dysprosium is prepared.
[0010] Preferably, in step (4), the desorbent is any one of dilute hydrochloric acid, sulfuric acid, nitric acid, sodium chloride, sodium hydroxide, and ultrapure water with a concentration of 0.1 - 1 mol / L, the temperature is 20 - 30 °C, and the desorption time is 3 - 5 h; the desorption effect is good, and the desorption rate can reach 100%. After five desorption cycles, the adsorption rate and desorption rate can still reach 99%.
[0011] Preferably, the pH values of the waste neodymium-iron-boron simulated solution in step (2) and the neodymium-dysprosium-containing solution after desorption in step (5) are adjusted to 6-7; finally, adsorption is used for 2-4 separation times to separate and purify neodymium and dysprosium, and the purification rate of dysprosium reaches 99.99% and the purification rate of neodymium reaches 99.99%. The waste neodymium-iron-boron simulated solution involved in the present invention contains other impurity elements, and the impurity elements are elements such as iron, cobalt, praseodymium, manganese, nickel, and aluminum.
[0012] The beneficial effects of the present invention are as follows: high-purity neodymium and dysprosium are directly extracted from the neodymium-iron-boron simulated solution through the processes of adsorption separation and desorption, realizing the separation of neodymium and dysprosium from other impurity elements, especially greatly reducing the influence of cobalt, and preparing a high-purity neodymium-dysprosium product, with the purification rate of dysprosium reaching 99.99% and the purification rate of neodymium reaching 99.99%; strictly controlling the influence of cobalt on the subsequent electrolysis of high-purity metals, greatly reducing the content of impurity elements, overall improving the purity of neodymium and dysprosium, effectively reducing the content of other impurities in the electrolysis process, and providing technical support for the electrolysis of high-purity metals of neodymium and dysprosium. Description of the Drawings
[0013] Figure 1 It is a flow chart of the preparation of the P-D331 adsorbent and the adsorption and purification of neodymium and dysprosium in Example 1.
[0014] Figure 2 It is the selective adsorption distribution ratio of the P-D331 adsorbent in Example 1.
[0015] Figure 3 It is the effect of desorbing cobalt, neodymium, and dysprosium from the P-D331 adsorbent by different types of desorbents in Example 1.
[0016] Figure 4 It is a graph of the experimental exploration of the reusability of P-331 in Example 1.
[0017] Figure 5 It is an XRD phase analysis diagram of P-D331 in Example 1.
[0018] Figure 6 It is an effect diagram of the primary adsorption and separation of neodymium and dysprosium in Example 1. Detailed Embodiments
[0019] The following further elaborates on the present invention in detail with reference to specific embodiments. Embodiment
[0020] As Figure 1 shown, the method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets by combining phosphorylated epoxy resin P-D331 and ZnO-MOF of the present invention includes the following steps: Preparation of P-D331 adsorbent for simultaneous separation of neodymium and dysprosium: First, weigh 5 g of D331 in a round-bottom flask, then add 1 g of TBP and an appropriate amount of dichloromethane mixed solution. Set the rotation speed to 90 r / min, the temperature to room temperature, and perform rotary evaporation under a vacuum pressure of 95 - 45 KPa. Lower the pressure by 5 KPa every 30 min. When the pressure reaches 45 KPa, perform rotary evaporation at a water bath temperature of 40 °C for 1 h to completely evaporate dichloromethane. Let TBP penetrate into the mesopores of D331 through the slow volatilization of dichloromethane, and load phosphate groups onto the D331 carrier. After rotary evaporation, stabilize the phosphate groups by vacuum drying for 12 h. Finally, wash with ultrapure water and ethanol, and then vacuum dry for 12 h to obtain the P-D331 adsorbent. The results of the phase analysis of the material are as Figure 5 shown. The contents of N, C, O, H, and S in the P-D331 adsorbent are 13.81%, 45.89%, 31.25%, 8.39%, and 3.64% respectively. The adsorption capacity for neodymium is 101.936 mg / g.
[0021] Simulated solution of waste Nd-Fe-B permanent magnet: Neodymium, dysprosium, cobalt, praseodymium, manganese, and nickel account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05%, and 0.02% respectively, and adjust the pH of the solution to 6; (3)Simultaneous adsorption and separation of neodymium and dysprosium: At room temperature, use P-D331 to simultaneously adsorb and separate neodymium and dysprosium from the multi-ion solution in the weak acid system in step (2). Neodymium and dysprosium are simultaneously adsorbed into the adsorption material. The solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 25 °C, and the adsorption time is 2 h. The adsorption capacity results of the adsorbent for each element are as Figure 2 shown. When the pH is 6, the adsorbent has a high distribution ratio for neodymium and dysprosium and good selective adsorption performance.
[0022] (4)Preparation of separators: Preparation of separators for separate separation of neodymium and dysprosium: Use the topological transformation method to pyrolyze Zn-MOF into hierarchical porous zinc oxide (ZnO-MOF), and utilize its unique oxygen vacancy concentration gradient and lattice distortion effect to prepare a separator ZnO-MOF with selective adsorption for dysprosium.
[0023] (5)Desorption of neodymium and dysprosium: Select hydrochloric acid, etc. as the desorbent for desorption. The solid-liquid ratio is 0.1 g / 20 mL, the concentration of the acid is 6 mol / L, and it is carried out at room temperature. The desorption results of neodymium and dysprosium are as Figure 3 shown. The desorption effect with 6 mol / L hydrochloric acid is the most ideal, and the desorption rates of dysprosium and neodymium reach 99.74% and 100% respectively, without the need to add additional agents.
[0024] (6) Reusability investigation: Using 6 mol / L hydrochloric acid as the desorbent and a solid-liquid ratio of 0.1 g / 20 mL, cyclic adsorption-desorption studies were carried out to further evaluate the reusability of the P-D331 adsorption material. The experimental results of the reusability performance are as Figure 4 shown. After five cycles of experiments, the adsorption and desorption rates of P-D331 for Nd(Ⅲ) and Dy(Ⅲ) can still reach over 99%, proving that the material has good reusability.
[0025] (7) Separation and purification: For the neodymium- and dysprosium-containing solution after desorption in (5), the separator ZnO-MOF prepared in (4) was used for the separation of neodymium and dysprosium, with the pH adjusted to 6. The separation process is as Figure 1 shown. After using adsorption to perform three separations on the desorption solution, neodymium and dysprosium ion solutions after complete separation of neodymium and dysprosium can be obtained. The separation results of ZnO-MOF and Zn-MOF are as Figure 6 shown. This ZnO-MOF material can purify and separate neodymium and dysprosium. Example
[0026] Preparation of P-D331 adsorbent for simultaneous separation of neodymium and dysprosium: First, weigh 5 g of D331 in a round-bottom flask, then add 0.5 g of TBP and an appropriate amount of dichloromethane mixed solution. Set the rotation speed to 90 r / min, the temperature to room temperature, and perform rotary evaporation under a vacuum pressure of 95 - 45 KPa. Lower the pressure by 5 KPa every 30 min. When the pressure is 45 KPa, perform rotary evaporation at a water bath temperature of 40 °C for 1 h to completely evaporate dichloromethane. Let TBP penetrate into the mesopores of D331 through the slow volatilization of dichloromethane, and load the phosphate group onto the D331 carrier. After rotary evaporation, stabilize the phosphate group by vacuum drying for 12 h. Finally, wash with ultrapure water and ethanol, and then vacuum dry for 12 h to prepare the P-D331 adsorbent. The results of the phase analysis of the material are as Figure 5 shown. The contents of N, C, O, H, and S in the P-D331 adsorbent are 13.81%, 45.89%, 31.25%, 8.39%, and 3.64% respectively. The adsorption capacity for neodymium is 88.136 mg / g.
[0027] Leaching solution of Nd-Fe-B permanent magnet: Neodymium, dysprosium, cobalt, praseodymium, manganese, nickel account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05%, and 0.02% respectively, and adjust the pH of the solution to 6; (3) Simultaneous adsorption and separation of neodymium and dysprosium: At room temperature, use P-D331 to simultaneously adsorb and separate neodymium and dysprosium from the multi-ion solution in the weak acid system in step (2). Neodymium and dysprosium are simultaneously adsorbed into the adsorption material. The solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 25 °C, and the adsorption time is 2 h. The adsorption capacity results of the adsorbent for each element are as Figure 2As shown in the figure. When the pH is 6, the adsorbent has a high distribution ratio for neodymium and dysprosium and good selective adsorption performance.
[0028] (4) Preparation of the separating agent: Preparation of the separating agent for neodymium and dysprosium separately: Using the topological transformation method, Zn-MOF is pyrolyzed into hierarchical porous zinc oxide (ZnO-MOF). By utilizing its unique oxygen vacancy concentration gradient and lattice distortion effect, the separating agent ZnO-MOF with selective adsorption for dysprosium is prepared.
[0029] (5) Desorption experiment: Sodium hydroxide is selected as the desorbent for desorption. The solid-liquid ratio is 0.1 g / 20 mL, the concentration is 1 mol / L, and the experiment is carried out at room temperature. The desorption results of neodymium and dysprosium are as Figure 3 shown. The desorption effect with 6 mol / L hydrochloric acid is the most ideal. The desorption rates of dysprosium and neodymium reach 99.74% and 100% respectively, and there is no need to add additional agents.
[0030] (6) Exploration of reusability: Using 6 mol / L hydrochloric acid as the desorbent and the solid-liquid ratio of 0.1 g / 20 mL, the cyclic adsorption-desorption study is carried out to further evaluate the reusability of the P-D331 adsorbent. The experimental results of the reusability performance are as Figure 4 shown. After five cyclic experiments, the adsorption and desorption rates of P-D331 for Nd(Ⅲ) and Dy(Ⅲ) can still reach more than 99%, proving that the material has good reusability.
[0031] (7) Separation and purification: For the neodymium and dysprosium-containing solution after desorption in (5), the separating agent ZnO-MOF prepared in (4) is used for the separation of neodymium and dysprosium. The pH is adjusted to 6, and the separation process is as Figure 1 shown. After separation, the neodymium and dysprosium ion solutions after complete separation of neodymium and dysprosium can be obtained. Example
[0032] Preparation of the P-D331 adsorbent for simultaneous separation of neodymium and dysprosium: First, weigh 5 g of D331 in a round-bottom flask, then add 1.5 g of TBP and an appropriate amount of dichloromethane mixed solution. The rotation speed is set to 90 r / min, the temperature is room temperature, and rotary evaporation is carried out under a vacuum pressure of 95 - 45 KPa. The pressure is reduced by 5 KPa every 30 min. When the pressure is 45 KPa, rotary evaporation is carried out at a water bath temperature of 40 °C for 1 h to completely evaporate dichloromethane. The TBP is infiltrated into the mesopores of D331 by the slow volatilization of dichloromethane, and the phosphate group is carried on the D331 carrier. After rotary evaporation, the phosphate group is stabilized by vacuum drying for 12 h. Finally, it is washed with ultrapure water and ethanol, and finally vacuum dried for 12 h to prepare the P-D331 adsorbent. The results of the phase analysis of the material are as Figure 5As shown in the figure. The contents of N, C, O, H, and S in the P-D331 adsorbent are 13.81%, 45.89%, 31.25%, 10.66%, and 3.64% respectively. The adsorption capacity for neodymium is 93.42 mg / g.
[0033] Neodymium-iron-boron permanent magnet leaching solution: neodymium, dysprosium, cobalt, praseodymium, manganese, nickel, respectively account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05%, 0.02%, and the pH of the solution is adjusted to 6; (3)Simultaneous adsorption and separation of neodymium and dysprosium: At room temperature, use P-D331 to simultaneously adsorb and separate neodymium and dysprosium from the multi-ion ionic solution in the weak acid system in step (2). Neodymium and dysprosium are simultaneously adsorbed into the adsorbent material. The solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 25 °C, and the adsorption time is 2 h. The adsorption capacity results of the adsorbent for each element are as Figure 2 shown. When the pH is 6, the adsorbent has a high distribution ratio for neodymium and dysprosium and good selective adsorption performance.
[0034] (4)Preparation of separating agent: Preparation of neodymium and dysprosium separate separating agent: Use the topological transformation method to pyrolyze Zn-MOF into hierarchical porous zinc oxide (ZnO-MOF), and use its unique oxygen vacancy concentration gradient and lattice distortion effect to prepare a separating agent ZnO-MOF with selective adsorption for dysprosium.
[0035] (5)Desorption experiment: Select sodium chloride solution as the desorbent for desorption. The solid-liquid ratio is 0.1 g / 20 mL, the concentration is 1 mol / L, and it is carried out at room temperature. The desorption results of neodymium and dysprosium are as Figure 3 shown. The desorption effect with 6 mol / L hydrochloric acid is the most ideal. The desorption rates of dysprosium and neodymium reach 99.74% and 100% respectively, and there is no need to add additional agents.
[0036] (6)Investigation of reusability: Use 6 mol / L hydrochloric acid as the desorbent, with a solid-liquid ratio of 0.1 g / 20 mL, and conduct cyclic adsorption-desorption research to further evaluate the reusability of the P-D331 adsorbent material. The experimental results of the reusability performance are as Figure 4 shown. After five cyclic experiments, the adsorption and desorption rates of P-D331 for Nd(Ⅲ) and Dy(Ⅲ) can still reach more than 99%, proving that the material has good reusability.
[0037] (7)Separation and purification: Use the separating agent ZnO-MOF prepared in (4) to separate neodymium and dysprosium from the neodymium and dysprosium-containing solution after desorption in (5), adjust the PH to 6, and the separation process is as Figure 1 shown. After separation, neodymium and dysprosium ion solutions with complete separation of neodymium and dysprosium can be obtained. Example
[0038] Preparation of P-D331 adsorbent for simultaneous separation of neodymium and dysprosium: First, weigh 5 g of D331 into a round-bottom flask, then add 0.1 g of TBP and an appropriate amount of dichloromethane mixed solution. Set the rotation speed to 90 r / min, the temperature to room temperature, and perform rotary evaporation under a vacuum pressure of 95 - 45 KPa. Lower the pressure by 5 KPa every 30 min. When the pressure reaches 45 KPa, perform rotary evaporation at a water bath temperature of 40 °C for 1 h to completely evaporate dichloromethane. Let TBP penetrate into the mesopores of D331 through the slow volatilization of dichloromethane, and carry phosphoric acid groups onto the D331 carrier. After rotary evaporation, stabilize the phosphoric acid groups by vacuum drying for 12 h. Finally, wash with ultrapure water and ethanol, and then vacuum dry for 12 h to obtain the P-D331 adsorbent. The results of the phase analysis of the material are as Figure 5 shown. The contents of N, C, O, H, and S in the P-D331 adsorbent are 13.81%, 45.89%, 31.25%, 1.53%, and 3.64% respectively. The adsorption capacity for neodymium is 85.328 mg / g.
[0039] Leaching solution of NdFeB permanent magnet: Neodymium, dysprosium, cobalt, praseodymium, manganese, and nickel account for 25.95%, 4.21%, 4.22%, 0.34%, 0.05%, and 0.02% respectively, and adjust the pH of the solution to 6; (3)Simultaneous adsorption and separation of neodymium and dysprosium: At room temperature, use P-D331 to simultaneously adsorb and separate neodymium and dysprosium from the multi-ion solution in the weak acid system in step (2). Neodymium and dysprosium are simultaneously adsorbed onto the adsorption material. The solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 25 °C, and the adsorption time is 2 h. The adsorption capacity results of the adsorbent for each element are as Figure 2 shown. When the pH is 6, the adsorbent has a high distribution ratio for neodymium and dysprosium and good selective adsorption performance.
[0040] (4)Preparation of separating agent: Preparation of separating agent for separate neodymium and dysprosium: Use the topological transformation method (gradient heating) to pyrolyze Zn-MOF into hierarchical porous zinc oxide (ZnO-MOF), and use its unique oxygen vacancy concentration gradient and lattice distortion effect to prepare a separating agent ZnO-MOF with selective adsorption for dysprosium.
[0041] (5)Desorption experiment: Select ultrapure water as the desorbent for desorption, with a solid-liquid ratio of 0.1 g / 20 mL, and perform at room temperature. The desorption results of neodymium and dysprosium are as Figure 3 shown. Desorb with 6 mol / L hydrochloric acid, and the desorption rates of dysprosium and neodymium reach 98.12% and 100% respectively, without the need to add additional agents.
[0042] (6)Investigation of reusability: Use 6 mol / L hydrochloric acid as the desorbent, with a solid-liquid ratio of 0.1 g / 20 mL, and conduct cyclic adsorption-desorption studies to further evaluate the reusability of the P-D331 adsorption material. The experimental results of the reusability performance are as Figure 4As shown. After five cyclic experiments, the adsorption and desorption rates of P-D331 for Nd(Ⅲ) and Dy(Ⅲ) can still reach over 99%, proving that the material has good reusability performance.
[0043] (7) Separation and purification: For the neodymium and dysprosium-containing solution after desorption in (5), the separator ZnO-MOF prepared in (4) is used for neodymium and dysprosium separation, and the pH is adjusted to 6. The separation process is as Figure 1 shown. After separation, neodymium and dysprosium ion solutions with complete separation of neodymium and dysprosium can be obtained.
[0044] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any change or simple replacement that can be thought of without creative work should be covered within the protection scope of the present invention.
Claims
1. A preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets, characterized in that, It includes the following steps: (1) Preparation of solid adsorbent: Using epoxy-based anion exchange resin as a carrier, phosphorylate it by rotary evaporation with tributyl phosphate to obtain a phosphorylated epoxy-based anion exchange resin solid adsorbent; (2) Adsorption of neodymium and dysprosium from waste NdFeB simulated solution: Use the solid adsorbent prepared in step (1) to simultaneously adsorb and separate neodymium and dysprosium from the waste NdFeB simulated solution, and neodymium and dysprosium are simultaneously adsorbed into the phosphorylated epoxy-based anion exchange resin; (3) Preparation of hierarchical porous zinc oxide separator: Pyrolyze the zinc oxide separator into a hierarchical porous zinc oxide separator by a topological transformation method; (4) Desorption of neodymium and dysprosium: Use a desorbent to desorb the phosphorylated epoxy-based anion exchange resin adsorbent after adsorbing neodymium and dysprosium in step (3) to obtain a desorption solution containing neodymium and dysprosium; (5) Separation and purification: For the neodymium- and dysprosium-containing solution after desorption in step (4), use the zinc oxide separator prepared in step (3) for adsorption to separately separate and purify neodymium and dysprosium; Repeat this step 2 - 4 times to purify neodymium and dysprosium separately.
2. The preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets according to claim 1, characterized in that: In the solid adsorbent in step (1), mesopores or the surface are attached with phosphate groups.
3. The preparation method for separating and purifying neodymium and dysprosium from waste Nd-Fe-B permanent magnets according to claim 1 or 2, characterized in that: The preparation process in step (1) is carried out on a rotary evaporator. First, weigh the epoxy-based anion exchange resin in a container, then add a mixed solution of tributyl phosphate and dichloromethane. Set the rotation speed to 80 - 100 r / min, the temperature to room temperature, and carry out rotary evaporation under a vacuum pressure of 95 - 45 KPa. Lower the pressure by 5 - 10 KPa every 25 - 35 min. When the pressure is 40 - 50 KPa, carry out rotary evaporation at a water bath temperature of 35 - 45 °C for 1 - 2 h to completely evaporate dichloromethane. Let dichloromethane slowly volatilize to bring tributyl phosphate into the mesopores of the epoxy-based anion exchange resin, and attach phosphate groups to the epoxy-based anion exchange resin carrier. After rotary evaporation, stabilize the phosphate groups by vacuum drying for 12 - 14 h, and finally wash with ultrapure water and ethanol, and then vacuum dry for 12 - 14 h to prepare the phosphorylated epoxy-based anion exchange resin adsorbent.
4. The preparation method for separating and purifying neodymium and dysprosium from waste Nd-Fe-B permanent magnets according to claim 1, characterized in that: In step (2), when the solid adsorbent adsorbs neodymium and dysprosium in NdFeB, the solid-liquid ratio is 0.1 g / 20 mL, the adsorption temperature is 20 - 30 °C, and the adsorption time is 2 - 3 h.
5. The preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets according to claim 1, characterized in that: In step (3), the hierarchical porous zinc oxide separator is pyrolyzed in a muffle furnace at a gradient controlled temperature of 25 - 750 °C. Using its oxygen vacancy concentration gradient and lattice distortion effect, a hierarchical porous zinc oxide separator with selective adsorption for dysprosium is prepared.
6. The preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets according to claim 1, characterized in that: In step (4), the desorbent is any one of dilute hydrochloric acid, sulfuric acid, nitric acid, sodium chloride, sodium hydroxide, and ultrapure water with a concentration of 0.1 - 1 mol / L, the temperature is 20 - 30 °C, and the desorption time is 3 - 5 h.
7. The preparation method for separating and purifying neodymium and dysprosium from waste neodymium-iron-boron permanent magnets according to claim 1, characterized in that: The pH value of the waste NdFeB simulated solution in step (2) and the neodymium- and dysprosium-containing solution after desorption in step (5) is adjusted to 6 - 7.