Treatment method of rare earth NdFeB waste

Abstract

The present invention discloses a method for treating rare earth NdFeB waste in the field of NdFeB waste treatment. The invention uses organic acid to replace the mineral strong acid used in hydrometallurgy, thereby reducing pollution to the environment and reducing the generation of toxic waste. The difference in solubility of rare earth ions in solvents of different polarities is used to separate rare earth elements with high selectivity. The organic polar solvent can reduce the coating effect of the solvent on the rare earth ions during the extraction process. There is competition and synergistic effect when neutral phosphine-type extractants and quaternary ammonium salt extractants chelate with rare earth ions, thereby improving the chelation efficiency of rare earth ions. Centrifugal separation is used to eliminate the emulsification effect, making the extraction process more thorough. The present invention realizes the efficient, rapid and highly selective separation of iron and rare earth elements in NdFeB waste. The rare earth elements can be used to prepare oxides, prepare rare earth metals or alloys, or directly sell them, thereby extending the rare earth industry chain, realizing the recycling of rare earth resources, and reducing mining and environmental pollution.

Description

Technical Field

[0001] The invention belongs to the field of NdFeB waste treatment, and in particular relates to a method for treating rare earth NdFeB waste. Background Art

[0002] NdFeB magnet is an important rare earth functional material with advantages such as high coercivity and large magnetic energy product. It is widely used in electronic information, new energy, medical equipment, CNC machines, wind power generation, aerospace and other fields. However, in the production process of NdFeB magnet, 25%-30% of waste will be generated. These wastes are precious secondary resources. If they are not recycled in a green, efficient and sustainable way, it will cause a huge waste of resources.

[0003] The main metals of NdFeB magnets are iron, praseodymium, and neodymium. In order to enhance the temperature stability and coercive force of NdFeB magnets, rare earth metals dysprosium and terbium are often added in production. Among the traditional treatment methods for rare earth NdFeB waste, hydrometallurgy is the one with the longest development and the most mature technology, and strong acid leaching is an important step in the hydrometallurgical process. However, mineral strong acids are used in the production process, which has a great impact on the environment, produces a large amount of toxic waste, and has high energy consumption and low utilization rate. Traditional rare earth separation methods require extraction agents for extraction. There are often problems such as severe emulsification, difficult phase separation, large amount of extraction agent, small separation coefficient, high stripping acid consumption, and low efficiency. Therefore, it is necessary to find a more environmentally friendly treatment method to reduce the generation of toxic aqueous and organic phase wastes, complete metal separation efficiently and quickly, reduce energy consumption, and improve resource utilization. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for treating rare earth NdFeB waste. In order to solve the problem that the mineral strong acid used in hydrometallurgy has a great impact on the environment and is easy to produce toxic waste, the present invention adopts an organic acid with less environmental pollution as a leaching agent and a stripping agent, utilizes the difference in solubility of rare earth ions in different solvents, utilizes centrifugal separation to eliminate the emulsification effect, improves the chelating efficiency of rare earth ions, and realizes the efficient, rapid and highly selective separation of iron, praseodymium, neodymium, dysprosium and terbium in NdFeB waste. The separated rare earth elements can be used to prepare the corresponding oxides, and can also be used to prepare rare earth metals, alloys or directly sold, thereby increasing the added value of rare earth NdFeB waste, extending the rare earth industry chain, realizing the recycling of rare earth resources, and reducing the mining of mineral resources and environmental pollution.

[0005] In order to achieve the above object, the following technical scheme is adopted: The present invention provides a method for treating rare earth NdFeB waste, and the method for treating rare earth NdFeB waste comprises the following steps:

[0006] (1) crushing and sieving NdFeB waste, leaching and dissolving the metal with an organic acid solution, filtering out insoluble impurities, controlling the pH with an organic acid, adding an oxidant for precipitation, filtering, and drying to obtain iron oxyhydroxide;

[0007] (2) mixing the rare earth aqueous phase obtained in step (1) with an organic polar solvent in proportion to obtain solution A, and mixing a neutral phosphine-type extractant, a quaternary ammonium salt extractant and a hydrocarbon solvent in proportion to obtain solution B;

[0008] (3) slowly adding the solution B to the solution A, then adding a salting-out agent, performing ultrasonic extraction, and centrifuging after extraction to obtain a rare earth organic phase and a rare earth aqueous phase;

[0009] (4) stripping the rare earth organic phase with an organic acid solution to obtain a praseodymium-neodymium aqueous phase and a dysprosium-terbium organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the praseodymium-neodymium aqueous phase for precipitation, filtering, washing, obtaining praseodymium-neodymium carbonate, and calcining at 950° C. to obtain praseodymium-neodymium oxide;

[0010] (5) adding the solution B to the rare earth aqueous phase and the dysprosium-terbium organic phase, performing ultrasonic extraction, adjusting the pH to 1.5-2.0 with an organic acid solution, performing back extraction to obtain a dysprosium-containing aqueous phase and a terbium-containing organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the dysprosium-containing aqueous phase to obtain a dysprosium carbonate precipitate, filtering, washing, and calcining at 900° C. to obtain dysprosium oxide;

[0011] (6) adding 2.5 mol / L ammonium bicarbonate solution to the terbium-containing organic phase to obtain terbium carbonate precipitate, washing it, and calcining it at 1000° C. to obtain terbium oxide.

[0012] Furthermore, the organic acid is one or more of malic acid, succinic acid, and sorbic acid; the concentration of the organic acid solution in step (1) is 2.0-4.0 mol / L; and the pH in step (1) is 2.0-3.5.

[0013] Furthermore, the oxidant is one of hydrogen peroxide, sodium hypochlorite, sodium sulfite and sodium pyrosulfate.

[0014] Furthermore, the organic polar solvent is one or more of polypropylene glycol 200, dipropylene glycol, pentaerythritol, and neopentyl glycol; and the volume ratio of the rare earth aqueous phase to the organic polar solvent is 2:1-3:1.

[0015] Furthermore, the neutral phosphine-type extractant is one or more of Cyanex600, Cyanex936, and Cyanex272.

[0016] Furthermore, the quaternary ammonium salt extractant is one or more of methyltriethylammonium chloride, trioctylmethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, didodecyldimethylammonium chloride, and didecyldimethylammonium chloride.

[0017] Furthermore, the hydrocarbon solvent is one of No. 100 solvent oil, No. 120 solvent oil, and No. 260 solvent oil.

[0018] Furthermore, the volume ratio of the neutral phosphine extractant, the quaternary ammonium salt extractant and the hydrocarbon solvent is 3-4:1-1.5:5-6.

[0019] Furthermore, the volume ratio of solution A to solution B is 3:1-3:2.

[0020] Furthermore, the salting-out agent is one or more of lithium chloride, sodium chloride and potassium chloride.

[0021] Furthermore, the ultrasonic extraction treatment time is 60-90 min, the temperature is 60-80° C., the frequency is 50-80 kHz, and the power is 180-250 W; the centrifugal separation treatment time is 20-30 min, and the speed is 600-1200 r / min.

[0022] Furthermore, the concentration of the organic acid solution in step (4) and step (5) is 1.3-3.5 mol / L.

[0023] The beneficial effects of the present invention are as follows: the present invention provides a method for treating rare earth neodymium iron boron waste, the present invention uses organic acid to replace the mineral strong acid used in traditional hydrometallurgy, reduces the pollution to the environment, and reduces the generation of toxic aqueous phase and organic phase waste; because praseodymium and neodymium have similar properties, praseodymium and neodymium are precipitated together to prepare praseodymium neodymium oxide, and then the solubility difference of rare earth ions in solvents of different polarities is used to separate praseodymium and neodymium from dysprosium and terbium with high selectivity; the organic polar solvent can reduce the coating effect of the solvent on the rare earth ions during the extraction process, and the neutral phosphine type extractant When chelating with rare earth ions, quaternary ammonium salt extractants have both competitive effect and synergistic effect, which greatly improves the chelation efficiency of rare earth ions; centrifugal separation is used to eliminate emulsification, making the extraction process more thorough, reducing stripping acid consumption and improving utilization rate; the present invention realizes efficient, rapid and highly selective separation of iron, praseodymium, neodymium, dysprosium and terbium, and the separated rare earth elements are used to prepare corresponding oxides, and can also be used to prepare rare earth metals or alloys or directly sell them, extending the rare earth industry chain, realizing the recycling of rare earth resources, and reducing the mining of mineral resources and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The process flow chart of the treatment method of rare earth NdFeB waste;

[0025] Figure 2 It is a line graph of the distribution ratio of neodymium and dysprosium in Examples 1-3 and Comparative Examples 1-3;

[0026] Figure 3 The figure is a bar graph showing the extraction efficiency of the extractants for neodymium and dysprosium in Examples 1-3 and Comparative Examples 1-3;

[0027] Figure 4 It is a line graph of the distribution ratio of dysprosium and terbium in Examples 1-3 and Comparative Examples 1-3;

[0028] Figure 5 It is a bar chart of the extraction efficiency of the extractants for dysprosium and terbium in Examples 1-3 and Comparative Examples 1-3.

[0029] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0032] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0033] Example 1

[0034] Treatment method of rare earth NdFeB waste

[0035] The method for treating rare earth NdFeB waste comprises the following steps:

[0036] (1) crushing and sieving NdFeB waste, leaching and dissolving the metal with an organic acid solution, filtering out insoluble impurities, controlling the pH with an organic acid, adding an oxidant for precipitation, filtering, and drying to obtain iron oxyhydroxide;

[0037] (2) mixing the rare earth aqueous phase obtained in step (1) with an organic polar solvent in proportion to obtain solution A, and mixing a neutral phosphine-type extractant, a quaternary ammonium salt extractant and a hydrocarbon solvent in proportion to obtain solution B;

[0038] (3) slowly adding the solution B to the solution A, then adding a salting-out agent, performing ultrasonic extraction, and centrifuging after extraction to obtain a rare earth organic phase and a rare earth aqueous phase;

[0039] (4) stripping the rare earth organic phase with an organic acid solution to obtain a praseodymium-neodymium aqueous phase and a dysprosium-terbium organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the praseodymium-neodymium aqueous phase for precipitation, filtering, washing, obtaining praseodymium-neodymium carbonate, and calcining at 950° C. to obtain praseodymium-neodymium oxide;

[0040] (5) adding the solution B to the rare earth aqueous phase and the dysprosium-terbium organic phase, performing ultrasonic extraction, adjusting the pH to 1.5-2.0 with an organic acid solution, performing back extraction to obtain a dysprosium-containing aqueous phase and a terbium-containing organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the dysprosium-containing aqueous phase to obtain a precipitate, filtering, washing, and calcining at 900° C. to obtain dysprosium oxide;

[0041] (6) adding 2.5 mol / L ammonium bicarbonate solution to the terbium-containing organic phase to obtain a precipitate, washing it, and calcining it at 1000° C. to obtain terbium oxide.

[0042] The organic acid is malic acid; the concentration of the organic acid solution in step (1) is 2.0 mol / L; the pH in step (1) is 2.0; the oxidant is hydrogen peroxide; the organic polar solvent is polypropylene glycol 200; the volume ratio of the rare earth aqueous phase to the organic polar solvent is 2:1; the neutral phosphine extractant is Cyanex600; the quaternary ammonium salt extractant is a mixture of methyl triethyl ammonium chloride and trioctyl methyl ammonium chloride in a mass ratio of 1:1; the hydrocarbon solvent is 100 No. solvent oil; the volume ratio of the neutral phosphine extractant, the quaternary ammonium salt extractant and the hydrocarbon solvent is 3:1:5; the volume ratio of solution A to solution B is 3:1; the salting-out agent is sodium chloride; the ultrasonic extraction treatment time is 60 minutes, the temperature is 60°C, the frequency is 50kHz, and the power is 180W; the centrifugal separation treatment time is 20 minutes, and the speed is 600r / min; the concentration of the organic acid solution in step (4) and step (5) is 1.3mol / L.

[0043] Example 2

[0044] Treatment method of rare earth NdFeB waste

[0045] The method for treating rare earth NdFeB waste comprises the same steps as those in Example 1.

[0046] Furthermore, the organic acid is malic acid; the concentration of the organic acid solution in step (1) is 4.0 mol / L; the pH in step (1) is 3.5; the oxidant is sodium hypochlorite; the organic polar solvent is dipropylene glycol; the volume ratio of the rare earth aqueous phase to the organic polar solvent is 3:1; the neutral phosphine extractant is Cyanex936; the quaternary ammonium salt extractant is tetradecyltrimethylammonium chloride; the volume ratio of the neutral phosphine extractant, the quaternary ammonium salt extractant and the hydrocarbon solvent is 3:1.5:6; the hydrocarbon solvent is No. 260 solvent oil; the volume ratio of solution A to solution B is 3:1; the salting-out agent is lithium chloride; the ultrasonic extraction treatment time is 60 min, the temperature is 75°C, the frequency is 80 kHz, and the power is 180 W; the centrifugal separation treatment time is 30 min, and the speed is 1200 r / min. The concentration of the organic acid solution in step (4) and step (5) is 3.5 mol / L.

[0047] Example 3

[0048] Treatment method of rare earth NdFeB waste

[0049] The method for treating rare earth NdFeB waste comprises the same steps as those in Example 1.

[0050] Furthermore, the organic acid is malic acid; the concentration of the organic acid solution in step (1) is 3.0 mol / L; the pH in step (1) is 3.0; the oxidant is sodium sulfite; the organic polar solvent is pentaerythritol; the volume ratio of the rare earth aqueous phase to the organic polar solvent is 2.5:1; the neutral phosphine extractant is Cyanex272; the quaternary ammonium salt extractant is a mixture of tetradecyltrimethylammonium chloride and dodecyltrimethylammonium chloride in a mass ratio of 2:1; the hydrocarbon solvent is No. 260 solvent oil; The volume ratio of the neutral phosphine extractant, the quaternary ammonium salt extractant and the hydrocarbon solvent is 3.5:1.2:5.6; the volume ratio of solution A to solution B is 3:1.5; the salting-out agent is a mixture of lithium chloride and potassium chloride in a mass ratio of 2:1; the ultrasonic extraction treatment time is 80 minutes, the temperature is 70°C, the frequency is 70kHz, and the power is 220W; the centrifugal separation treatment time is 25 minutes, and the speed is 900r / min; the concentration of the organic acid solution in step (4) and step (5) is 2.5mol / L.

[0051] Comparative Example 1

[0052] A method for treating rare earth neodymium iron boron waste

[0053] The difference between this comparative example and Example 1 is that the solution A does not contain an organic polar solvent, and an equal amount of water is used to replace the organic polar solvent. The remaining components, component contents, and treatment methods are the same as those in Example 1.

[0054] Comparative Example 2

[0055] A method for treating rare earth neodymium iron boron waste

[0056] The difference between this comparative example and Example 1 is that the solution B does not contain a quaternary ammonium salt extractant, and an equal amount of a neutral phosphine-type extractant is used to replace the quaternary ammonium salt extractant. The remaining components, component contents, and treatment methods are the same as those in Example 1.

[0057] Comparative Example 3

[0058] A method for treating rare earth neodymium iron boron waste

[0059] The difference between this comparative example and Example 1 is that the solution B does not contain a neutral phosphine-type extractant, and an equal amount of a quaternary ammonium salt extractant is used to replace the neutral phosphine-type extractant. The remaining components, component contents, and treatment methods are the same as those in Example 1.

[0060] Results Analysis

[0061] The metal recovery rates of Examples 1-3 and Comparative Examples 1-3 were calculated respectively, recovery rate = (recovery amount / initial content) × 100%. The results are shown in Table 1.

[0062] As can be seen from Table 1, the NdFeB waste treatment method provided by the present invention enables the recovery rates of various metals to reach more than 95%, and the recovery rate of rare earths to reach more than 96%, thus achieving the utilization rate of rare earth resources.

[0063] Table 1 Metal recovery rates of Examples 1-3 and Comparative Examples 1-3

[0064] Metal Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 iron 96.6％ 97.2％ 96.4％ 95.8％ 96.0％ 95.5％ neodymium 97.6％ 97.7％ 98.0％ 94.6％ 95.2％ 82.2％ praseodymium 97.6％ 97.2％ 96.8％ 95.8％ 94.8％ 92.2％ dysprosium 97.2％ 97.0％ 97.5％ 95.0％ 94.8％ 81.5％ terbium 96.6％ 96.2％ 96.8％ 93.8％ 89.8％ 88.2％

[0065] The distribution ratio and extraction efficiency of Nd and Dy in Examples 1-3 and Comparative Examples 1-3 were calculated by using arsenazo (III) colorimetry. The distribution ratio and extraction efficiency of Nd and Dy in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1. Figure 2 , Figure 3 As shown in the figure, the distribution ratio and extraction efficiency of dysprosium and terbium are as follows: Figure 4 , Figure 5 The rare earth separation coefficient is shown in Table 1.

[0066] Table 1 Separation coefficients of Nd:Dy, Dy:Tb for Examples 1-3 and Comparative Examples 1-3

[0067] category Nd:Dysprosium separation factor Separation coefficient of dysprosium and terbium Example 1 6.95 6.52 Example 2 9.51 9.76 Example 3 7.63 7.93 Comparative Example 1 4.10 4.50 Comparative Example 2 3.23 4.21 Comparative Example 3 3.33 3.41

[0068] The arsenazo (III) colorimetric determination method is as follows: first, use a pipette to transfer 5.00 mL of the shaken solution to be tested (organic phase or aqueous phase) and centrifuge it on a centrifuge at a rate of 5000 r / min for 10 minutes, then take 1.00 mL of the supernatant into a 10.00 mL volumetric flask, adjust the pH value to 3.0, then add 10.00 mL of 500 mg / L arsenazo (III) solution and 5 drops of masking agent disodium ethylenediaminetetraacetate, dilute to the scale with water, use a 1 cm colorimetric dish with a reagent blank as a reference, measure its absorbance at a wavelength of 652 nm, and calculate the content of rare earth metals in the organic phase or aqueous phase according to the calibration curve.

[0069] The distribution ratio D is defined as the actual concentration ratio of the extracted substance in the two phases when an extraction reaches equilibrium to express the distribution relationship of the substance, D = C 有 / C 水 , C 有 is the concentration of the extract in the organic phase at extraction equilibrium, C 水 When the extraction is in equilibrium, the concentration of the extract in the water phase is greater, indicating that the extract is easier to be extracted.

[0070] The extraction efficiency E is defined as the ratio of the amount of the substance extracted into the organic phase to the amount of the substance in the raw liquid when the extraction reaches equilibrium, E = D / [D + (V 水 / V 有 )]×100%, V 水 Indicates the volume of the liquid, V 有 It represents the volume of the organic phase. The larger E is, the easier it is for the extractant to be extracted.

[0071] The rare earth separation factor is defined as the ratio of the distribution ratios of the two rare earth metals, β 1，2 =D 1 / D 2 , β 1，2 The larger it is, the better the selectivity of the extractant is and the better the separation effect is.

[0072] From Table 1 and Figure 2-Figure 5 It can be seen that the separation coefficients of neodymium, dysprosium and dysprosium and terbium in Example 2 are the largest, indicating that the selectivity of the extractant under this comparative example is better and the separation effect is the best; comparing Example 1 with Comparative Examples 1-3, polar solvents can effectively reduce the coating effect of the solvent on rare earth ions during the extraction process, and the use of neutral phosphine-type extractants and quaternary ammonium salt extractants together has competition and synergistic effects, which significantly improves the separation efficiency of rare earth metals, and is better than using them alone.

[0073] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0074] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for treating rare earth NdFeB waste, characterized in that: The method for treating rare earth NdFeB waste comprises the following steps: (1) crushing and sieving NdFeB waste, leaching and dissolving the metal with an organic acid solution, filtering out insoluble impurities, controlling the pH with an organic acid, adding an oxidant for precipitation, filtering, and drying to obtain iron oxyhydroxide; (2) mixing the rare earth aqueous phase obtained in step (1) with an organic polar solvent in proportion to obtain solution A, and mixing a neutral phosphine-type extractant, a quaternary ammonium salt extractant and a hydrocarbon solvent in proportion to obtain solution B; (3) slowly adding the solution B to the solution A, then adding a salting-out agent, performing ultrasonic extraction, and centrifuging after extraction to obtain a rare earth organic phase and a rare earth aqueous phase; (4) stripping the rare earth organic phase with an organic acid solution to obtain a praseodymium-neodymium aqueous phase and a dysprosium-terbium organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the praseodymium-neodymium aqueous phase for precipitation, filtering, washing, obtaining praseodymium-neodymium carbonate, and calcining at 950° C. to obtain praseodymium-neodymium oxide; (5) adding the solution B to the rare earth aqueous phase and the dysprosium-terbium organic phase, performing ultrasonic extraction, adjusting the pH to 1.5-2.0 with an organic acid solution, performing back extraction to obtain a dysprosium-containing aqueous phase and a terbium-containing organic phase, adding a 2.5 mol / L ammonium bicarbonate solution to the dysprosium-containing aqueous phase to obtain a precipitate, filtering, washing, and calcining at 900° C. to obtain dysprosium oxide; (6) adding 2.5 mol / L ammonium bicarbonate solution to the terbium-containing organic phase to obtain a precipitate, washing it, and calcining it at 1000° C. to obtain terbium oxide.

2. The method for treating rare earth NdFeB waste according to claim 1, characterized in that: The organic acid is one or more of malic acid, succinic acid, and sorbic acid; the concentration of the organic acid solution in step (1) is 2.0-4.0 mol / L; and the pH in step (1) is 2.0-3.

5.

3. The method for treating rare earth NdFeB waste according to claim 2, characterized in that: The oxidant is one of hydrogen peroxide, sodium hypochlorite, sodium sulfite and sodium pyrosulfate.

4. The method for treating rare earth NdFeB waste according to claim 3, characterized in that: The organic polar solvent is one or more of polypropylene glycol 200, dipropylene glycol, pentaerythritol and neopentyl glycol; the volume ratio of the rare earth aqueous phase to the organic polar solvent is 2:1-3:

1.

5. The method for treating rare earth NdFeB waste according to claim 4, characterized in that: The neutral phosphine extractant is one or more of Cyanex600, Cyanex936, and Cyanex272; the quaternary ammonium salt extractant is one or more of methyltriethylammonium chloride, trioctylmethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium chloride, didodecyldimethylammonium chloride, and didecyldimethylammonium chloride.

6. The method for treating rare earth NdFeB waste according to claim 5, characterized in that: The hydrocarbon solvent is one of No. 100 solvent oil, No. 120 solvent oil and No. 260 solvent oil.

7. The method for treating rare earth NdFeB waste according to claim 6, characterized in that: The volume ratio of the neutral phosphine extractant, the quaternary ammonium salt extractant and the hydrocarbon solvent is 3-4:1-1.5:5-6.

8. The method for treating rare earth NdFeB waste according to claim 7, characterized in that: The volume ratio of solution A to solution B is 3:1-3:

2.

9. The method for treating rare earth NdFeB waste according to claim 8, characterized in that: The salting-out agent is one or more of lithium chloride, sodium chloride and potassium chloride.

10. The method for treating rare earth NdFeB waste according to claim 9, characterized in that: The ultrasonic extraction treatment time is 60-90 minutes, the temperature is 60-80°C, the frequency is 50-80kHz, and the power is 180-250W; the centrifugal separation treatment time is 20-30 minutes, and the speed is 600-1200r / min; the concentration of the organic acid solution in step (4) and step (5) is 1.3-3.5mol / L.

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