CN113724992A - Neodymium iron boron rare earth permanent magnet waste regenerated magnet and preparation method thereof - Google Patents
Neodymium iron boron rare earth permanent magnet waste regenerated magnet and preparation method thereof Download PDFInfo
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- CN113724992A CN113724992A CN202110989079.5A CN202110989079A CN113724992A CN 113724992 A CN113724992 A CN 113724992A CN 202110989079 A CN202110989079 A CN 202110989079A CN 113724992 A CN113724992 A CN 113724992A
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- 239000002699 waste material Substances 0.000 title claims abstract description 114
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 85
- 229910001172 neodymium magnet Inorganic materials 0.000 title claims abstract description 58
- -1 Neodymium iron boron rare earth Chemical class 0.000 title claims abstract description 27
- 238000002360 preparation method Methods 0.000 title claims abstract description 24
- 239000000843 powder Substances 0.000 claims abstract description 95
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 54
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 43
- 239000000956 alloy Substances 0.000 claims abstract description 43
- 238000010438 heat treatment Methods 0.000 claims abstract description 34
- 238000002156 mixing Methods 0.000 claims abstract description 20
- 238000005245 sintering Methods 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims abstract description 11
- 238000000465 moulding Methods 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 51
- 239000001257 hydrogen Substances 0.000 claims description 37
- 229910052739 hydrogen Inorganic materials 0.000 claims description 37
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 35
- 230000008569 process Effects 0.000 claims description 35
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 20
- 239000001301 oxygen Substances 0.000 claims description 20
- 229910052760 oxygen Inorganic materials 0.000 claims description 20
- 238000000462 isostatic pressing Methods 0.000 claims description 16
- 239000000314 lubricant Substances 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 13
- 238000005406 washing Methods 0.000 claims description 10
- 239000003963 antioxidant agent Substances 0.000 claims description 9
- 230000003078 antioxidant effect Effects 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 9
- 238000002844 melting Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 9
- 239000013078 crystal Substances 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 7
- 238000006356 dehydrogenation reaction Methods 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 238000000227 grinding Methods 0.000 claims description 6
- 238000003801 milling Methods 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 6
- 229910052779 Neodymium Inorganic materials 0.000 claims description 4
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 3
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 3
- 230000006698 induction Effects 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 3
- 229910052689 Holmium Inorganic materials 0.000 claims description 2
- 238000012387 aerosolization Methods 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052733 gallium Inorganic materials 0.000 claims description 2
- 238000009689 gas atomisation Methods 0.000 claims description 2
- 238000004064 recycling Methods 0.000 claims description 2
- 150000002431 hydrogen Chemical class 0.000 claims 2
- 239000000463 material Substances 0.000 abstract description 14
- 238000011084 recovery Methods 0.000 abstract description 10
- 239000003153 chemical reaction reagent Substances 0.000 abstract description 3
- QJVKUMXDEUEQLH-UHFFFAOYSA-N [B].[Fe].[Nd] Chemical compound [B].[Fe].[Nd] QJVKUMXDEUEQLH-UHFFFAOYSA-N 0.000 description 13
- 239000010812 mixed waste Substances 0.000 description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- 238000005554 pickling Methods 0.000 description 8
- 238000003860 storage Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 6
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000004381 surface treatment Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000004806 packaging method and process Methods 0.000 description 4
- 238000007873 sieving Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000005324 grain boundary diffusion Methods 0.000 description 3
- 150000002632 lipids Chemical class 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- 229910052771 Terbium Inorganic materials 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000013467 fragmentation Methods 0.000 description 2
- 238000006062 fragmentation reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910018229 Al—Ga Inorganic materials 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910000807 Ga alloy Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- XOYZEBISYWDKED-UHFFFAOYSA-N copper neodymium Chemical compound [Cu].[Nd] XOYZEBISYWDKED-UHFFFAOYSA-N 0.000 description 1
- 239000011258 core-shell material Substances 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005347 demagnetization Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/0266—Moulding; Pressing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Hard Magnetic Materials (AREA)
Abstract
The invention provides a neodymium iron boron rare earth permanent magnet waste regenerated magnet and a preparation method thereof. The preparation method comprises the following steps: and mixing the rare earth waste powder with the R-M alloy powder to obtain mixed fine powder, and sequentially carrying out molding, sintering and heat treatment on the mixed fine powder to obtain the neodymium iron boron rare earth permanent magnet waste regenerated magnet. In the invention, the waste materials are directly utilized to prepare the regenerated magnet by using the short-flow controllable preparation process, no new materials are required to be added, the recovery efficiency is greatly improved, the recovery cost is reduced, the introduction of chemical reagents is eliminated in the production process, the recovery process is more environment-friendly, the waste materials containing Ce are utilized in a large amount, and the problem of overstocking of the existing large amount of waste materials containing Ce is solved.
Description
Technical Field
The invention belongs to the technical field of magnetic material preparation, relates to a magnet prepared from neodymium iron boron rare earth permanent magnet waste, and particularly relates to a neodymium iron boron rare earth permanent magnet waste regenerated magnet and a preparation method thereof.
Background
Since the advent of self-sintered nd-fe-b, it has developed rapidly due to its excellent magnetic properties and is now an indispensable functional material in modern industry. China is the first major country for producing rare earth permanent magnet materials, the capacity exceeds 30 million tons, and the yield accounts for more than 80% of the total world production. In recent 30 years, the application amount of rare earth in permanent magnet materials in China is increased by more than 70 times, a large amount of rare earth elements such as Pr, Nd, Dy, Tb and the like which are in short supply are consumed, and a large amount of abundant rare earth elements such as La, Ce and the like which are associated in rare earth ores are accumulated, so that the utilization of the rare earth resources is greatly unbalanced. With the successful research and development and popularization of rare earth permanent magnet Ce, the application amount of high-abundance rare earth Ce is greatly increased, meanwhile, the unbalanced utilization degree of rare earth resources is relieved to a certain extent due to the local reduction of the use amounts of Pr and Nd, and the annual production amount of Ce-containing magnets in 2019 exceeds 4 ten thousand tons.
CN110993311A discloses a method for preparing a high-performance bulk neodymium-iron-boron magnet by grain boundary diffusion, wherein an RxMy alloy film layer is respectively coated on one coating surface of each thin neodymium-iron-boron magnet, a GaFb alloy film layer is coated on the other coating surface of each thin neodymium-iron-boron magnet, a plurality of thin neodymium-iron-boron magnets coated with the RxMy alloy film layers and the GaFb alloy film layers are laminated and arranged in the thickness direction without intervals to obtain a laminated parison, then, the laminated parison is subjected to heat treatment in a vacuum environment or an inert gas protection environment to obtain the high-performance bulk neodymium-iron-boron magnet, and in the heat treatment process, element mutual diffusion occurs between each thin neodymium-iron-boron magnet and the RxMy alloy film layers and the GaFb alloy film layers coated on the thin neodymium-iron-boron magnet to form a transition layer; the preparation method has the advantages that the limitation of a crystal boundary diffusion technology on the size of the neodymium iron boron magnet is broken through, the preparation of the high-performance bulk neodymium iron boron magnet is realized, the coercive force of the bulk neodymium iron boron magnet is obviously improved, and the influence on remanence is reduced.
CN112331468A discloses a preparation method of a high-remanence sintered neodymium-iron-boron magnet, which comprises the steps of completely melting and uniformly stirring a neodymium-iron-boron alloy raw material in a crucible of a sheet throwing furnace to obtain an alloy liquid, reducing the temperature of the alloy liquid to the range of +/-20 ℃ of the eutectic point, keeping electromagnetic stirring for 5-15 min, then rapidly cooling to obtain an alloy cast sheet, carrying out hydrogen crushing and grinding to obtain powder, filling the powder into a die cavity of a forming die, and carrying out primary compression under an oriented magnetic field of more than or equal to 1.8T to obtain a sintered neodymium-iron-boron magnet with the density of 3.3-3.6 g/cm3Then in an orientation of 2.0T or moreThe secondary compression is carried out under the magnetic field to obtain the product with the density of 3.9-4.6 g/cm3Finally, vacuum sintering and tempering are carried out on the formed blank to obtain a high-remanence sintered neodymium-iron-boron magnet; the method has the advantages of improving the volume fraction of the T1 phase in the alloy cast sheet and the saturation rotation degree of the magnet, and having higher remanence which is more than 15.0 kGs.
CN110111961A discloses a preparation method of a high-coercivity neodymium iron boron magnet and the neodymium iron boron magnet, and the preparation method comprises the following steps: mixing neodymium-iron-boron powder and a low-melting-point metal adhesive, and performing static pressure forming to obtain a compacted neodymium-iron-boron rough blank; mixing a material containing heavy rare earth elements with neodymium iron boron powder, heating to a molten state to obtain a heavy rare earth source molten mass; heating the neodymium iron boron rough blank in a protective atmosphere until the heating temperature is 200-250 ℃ higher than the melting point of the adhesive, and carrying out heat preservation for 2-3 h; heating the treated neodymium iron boron rough blank to 950 ℃, immersing the neodymium iron boron rough blank into a heavy rare earth source molten mass, vacuumizing the neodymium iron boron rough blank, introducing protective gas into the environment for pressurization, and taking out the neodymium iron boron rough blank after the impregnation time is reached to obtain a neodymium iron boron rough blank crude product; the neodymium iron boron rough blank is subjected to surface treatment to obtain a neodymium iron boron magnet finished product, the grain boundary diffusion effect of the obtained neodymium iron boron magnet is good, and the coercive force strengthening effect is higher than that of the neodymium iron boron magnet obtained by the existing grain boundary diffusion heavy rare earth element process.
However, the shape of the sintered Nd-Fe-B rare earth permanent magnet material is single due to the limitation of the molding mode, and a large amount of processing excess materials are inevitably generated in the subsequent processing process, so that material waste is caused, and the production cost is increased. With the rising price of rare earth and the non-regenerability of rare earth resources, the recovery of processing excess materials becomes significant, and therefore, a utilization method for sintered neodymium iron boron waste materials needs to be developed urgently.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a neodymium iron boron rare earth permanent magnet waste regenerated magnet and a preparation method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a preparation method of a neodymium iron boron rare earth permanent magnet waste regenerated magnet, which comprises the following steps:
and mixing the rare earth waste powder with the R-M alloy powder to obtain mixed fine powder, and sequentially carrying out molding, sintering and heat treatment on the mixed fine powder to obtain the neodymium iron boron rare earth permanent magnet waste regenerated magnet.
In the invention, the waste materials are directly utilized to prepare the regenerated magnet by using the short-flow controllable preparation process, no new materials are required to be added, the recovery efficiency is greatly improved, the recovery cost is reduced, the introduction of chemical reagents is eliminated in the production process, the recovery process is more environment-friendly, the waste materials containing Ce are utilized in a large amount, and the problem of overstocking of the existing large amount of waste materials containing Ce is solved.
The R-M alloy powder in the present invention is a monodisperse alloy powder, and the monodisperse means that a certain parameter of the material has homogeneity.
As a preferable technical scheme of the invention, the rare earth waste powder is prepared by adopting the following method:
and (3) classifying and recycling the rare earth waste, and then sequentially carrying out acid washing, washing and drying, hydrogen crushing, screening and grinding to obtain the rare earth waste powder.
Preferably, the rare earth waste comprises Ce-containing rare earth waste and Ce-free rare earth waste.
Preferably, the mass ratio of the Ce-containing waste powder to the Ce-free waste powder is 1: (1-4), for example, may be 1: 1. 1: 2. 1: 3. 1: 4, but are not limited to the recited values, and other values not recited within the range are equally applicable.
Preferably, the particle size of the rare earth scrap powder is 3 to 5 μm, for example, 3 μm, 4 μm, 5 μm, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
As a preferable technical scheme of the invention, the hydrogen crushing process is carried out in a hydrogen crushing furnace.
Preferably, the pressure at the time of hydrogen absorption reaction in the hydrogen fragmentation process is 0.1 to 0.2MPa, and examples thereof include 0.1MPa, 0.11MPa, 0.12MPa, 0.13MPa, 0.14MPa, 0.15MPa, 0.16MPa, 0.17MPa, 0.18MPa, 0.19MPa, and 0.2MPa, but the values are not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, the temperature of the dehydrogenation reaction in the hydrogen fragmentation process is 500 to 600 ℃, and may be, for example, 500 ℃, 510 ℃, 520 ℃, 530 ℃, 540 ℃, 550 ℃, 560 ℃, 570 ℃, 580 ℃, 590 ℃, 600 ℃, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the screening process is performed in a vibrating screen.
As a preferable technical scheme of the invention, the lubricant and the antioxidant are added into the rare earth waste material in the grinding process.
The amount of the lubricant added is preferably 1 to 1.5mL/kg, and may be, for example, 1mL/kg, 1.1mL/kg, 1.2mL/kg, 1.3mL/kg, 1.4mL/kg, or 1.5mL/kg, but is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned range are also applicable.
The invention particularly limits the addition amount of the lubricant added into the rare earth waste material to be 1-1.5 mL/kg, because when the addition amount exceeds the limit value of 1.5mL/kg, the content of C element in the sintered magnet is increased, so that the performance of the magnet is reduced, and meanwhile, the addition amount exceeds the limit value, so that the probability of material fracture is increased, because the lubricant contains lipid substances, no residue exists after sintering is finished when the addition amount is low, and the content of residual C in the lipid substances is increased when the addition amount is more than the limit value, and the material fracture is caused by the residue of the lipid substances; when the amount added is less than the limit value of 1mL/kg, a decrease in the abrasive speed, an increase in the oxygen content of the powder and a decrease in the degree of orientation are caused, because when the amount added of the lubricant is less than the limit value, the ability of the lubricant to coat the powder is reduced, and the effect of the lubricant is deteriorated.
Preferably, the antioxidant is added in an amount of 0.01 to 0.015 wt.%, for example, 0.01 wt.%, 0.011 wt.%, 0.012 wt.%, 0.013 wt.%, 0.014 wt.%, 0.015 wt.%, based on 100 wt.% of the rare earth scrap, but is not limited to the recited values, and other values not recited in the above range are also applicable.
Preferably, the milling process is carried out in a jet mill.
Preferably, the rotor speed of the jet mill is 4000 to 5500r/min, for example 4000r/min, 4100r/min, 4200r/min, 4300r/min, 4400r/min, 4500r/min, 4600r/min, 4700r/min, 4800r/min, 4900r/min, 5000r/min, 5100r/min, 5200r/min, 5300r/min, 5400r/min, 5500r/min, but is not limited to the values listed, and other values not listed in this range of values are equally suitable.
Preferably, the jet mill is operated with an internal oxygen content of < 1ppm, such as 1ppm, 0.9ppm, 0.8ppm, 0.7ppm, 0.6ppm, 0.5ppm, but not limited to the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the pneumatic mill working pressure is 0.6 to 0.65MPa, for example, 0.6MPa, 0.61MPa, 0.62MPa, 0.63MPa, 0.64MPa, 0.65MPa, but is not limited to the values listed, and other values not listed in the numerical range are also applicable.
As a preferable technical scheme, the R-M alloy powder is prepared by a droplet-by-droplet gas atomization method.
Preferably, the droplet-by-droplet aerosolization process specifically comprises the steps of:
the R and M metals are melted completely and insulated through induction melting, a small hole is formed in the bottom of a melting crucible, piezoelectric ceramics are driven to vibrate through pulse signals, and R-M alloy liquid is extruded to flow out of the small hole in the bottom of the crucible in a small liquid drop mode, so that R-M alloy powder is obtained.
In a preferred embodiment of the present invention, R of the R-M alloy powder is any one of Pr, Nd, Ho, Dy, and Tb, and M is any one or a combination of at least two of Cu, Al, and Ga.
Preferably, the particle size of the R-M alloy powder is 30 to 100 μ M, and may be, for example, 30 μ M, 40 μ M, 50 μ M, 60 μ M, 70 μ M, 80 μ M, 90 μ M, or 100 μ M, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, the sphericity of the R-M alloy powder is 85 to 95%, and may be, for example, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
In a preferred embodiment of the present invention, the amount of the R-M alloy powder added is 1 to 2 wt.%, based on 100 wt.% of the rare earth scrap powder, and may be, for example, 1 wt.%, 1.2 wt.%, 1.4 wt.%, 1.6 wt.%, 1.8 wt.%, or 2 wt.%, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range of values are also applicable.
The invention particularly limits the addition amount of the R-M alloy powder to be 1-2 wt.%, because when the addition amount exceeds the limit value by 2 wt.%, the product of the remanence and the magnetic energy of the magnet is greatly reduced, because the density of the magnet is reduced due to the fact that the addition amount of the R-M alloy powder exceeds the limit value, the product of the remanence and the magnetic energy is reduced, and the excessive addition of the R-M alloy powder reduces the main phase ratio of the magnet and is also the reason for reducing the product of the remanence and the magnetic energy; when the addition amount is less than the limit value of 1 wt.%, the addition effect of R-M is not significant, and the coercive force is not improved significantly, because the R-M shell layer at the grain boundary does not completely wrap the main phase grains, so that the demagnetization coupling effect is weakened.
Preferably, the mixing time is 1 to 2 hours, for example, 1 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
As a preferable technical scheme of the invention, the forming process of the mixed fine powder is carried out in a full-automatic forming press and an isostatic press.
Preferably, the central orientation magnetic field of the molding process is > 2T, and may be, for example, 2.1T, 2.2T, 2.3T, 2.4T, 2.5T, but is not limited to the recited values, and other values not recited within the range of values are also applicable.
Preferably, the oxygen content of the shaping process is < 10ppm, and may be, for example, 1ppm, 2ppm, 4ppm, 6ppm, 8ppm, 9ppm, but is not limited to the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the density of the pressed blank after the mixed fine powder is formed is more than 3.8g/cm3For example, it may be 3.8g/cm3、3.9g/cm3、4.0g/cm3、4.1g/cm3、4.2g/cm3However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.
Preferably, the holding pressure of the isostatic pressing process is 200 to 250MPa, for example, 200MPa, 210MPa, 220MPa, 230MPa, 240MPa, 250MPa, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the pressure holding time of the isostatic pressing process is 30 to 60s, for example, 30s, 40s, 50s, 60s, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the density of the pressed blank after isostatic pressing is more than 4.1g/cm3It may be, for example, 4.2g/cm3、4.3g/cm3、4.4g/cm3、4.5g/cm3、4.6g/cm3However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.
In a preferred embodiment of the present invention, the sintering and the heat treatment are performed in a sintering furnace.
Preferably, the temperature of the sintering process is 1000 to 1060 ℃, for example, 1000 ℃, 1010 ℃, 1020 ℃, 1030 ℃, 1040 ℃, 1050 ℃, 1060 ℃, but is not limited to the recited values, and other values not recited in the range of the recited values are also applicable.
Preferably, the temperature holding time of the sintering process is 3 to 5 hours, such as 3 hours, 3.5 hours, 4 hours, 4.5 hours, and 5 hours, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the heat treatment process is a secondary heat treatment, and the temperature of the primary heat treatment is 800-900 ℃, for example, 800 ℃, 820 ℃, 840 ℃, 860 ℃, 880 ℃, 900 ℃; the secondary heat treatment temperature is 450 to 550 ℃, and may be, for example, 450 ℃, 470 ℃, 490 ℃, 510 ℃, 530 ℃, 550 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the temperature holding time of the heat treatment process is 3 to 10 hours, for example, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
As a preferred technical scheme of the present invention, the preparation method specifically comprises the following steps:
mixing rare earth waste powder containing Ce and rare earth waste powder not containing Ce, and then carrying out acid washing, washing and drying, hydrogen crushing, screening and grinding to obtain the rare earth waste powder, wherein the particle size of the rare earth waste powder is 3-5 mu m, and the mass ratio of the waste powder containing Ce to the waste powder not containing Ce is 1: (1-4);
the hydrogen crushing process is carried out in a hydrogen crushing furnace, wherein the pressure in the hydrogen absorption reaction is 0.1-0.2 MPa, the temperature in the dehydrogenation reaction is 500-600 ℃, the screening process is carried out in a vibrating screen, 1-1.5 mL/kg of lubricant and 0.01-0.015 wt.% of antioxidant are added into the rare earth waste in an airflow mill according to 100 wt.% of the mass of the rare earth waste, the rotating speed of a sorting wheel of the airflow mill is 4000-5500 r/min, the internal oxygen content is less than or equal to 1ppm during working, and the working pressure is 0.6-0.65 MPa;
(II) melting R and M metals completely through induction melting and preserving heat, arranging small holes at the bottom of a melting crucible, driving piezoelectric ceramics to vibrate through pulse signals, extruding R-M alloy liquid to enable the alloy liquid to flow out of the small holes at the bottom of the crucible in a small liquid droplet mode to obtain R-M alloy powder, wherein the grain diameter of the R-M alloy powder is 30-100 microns, the sphericity is 85-95%, the addition amount of the R-M alloy powder is 1-2 wt%, and the mixing time is 1-2 hours;
(III) the forming process of the mixed fine powder is carried out in a full-automatic forming press and an isostatic press, the central orientation magnetic field of the forming process is more than 2T, the oxygen content is less than 10ppm, and the density of a pressed blank after the mixed fine powder is formed is more than 3.8g/cm3The isostatic pressing holding pressure is 200-250 MPa, the pressure holding time is 30-60 s, and the density of the pressed blank after isostatic pressing is more than 4.1g/cm3；
(IV) sintering and heat treatment are carried out in a sintering furnace, the temperature in the sintering process is 1000-1060 ℃, the temperature holding time is 3-5 h, the heat treatment process is secondary heat treatment, the temperature of the primary heat treatment is 800-900 ℃, the temperature of the secondary heat treatment is 450-550 ℃, and the temperature holding time is 3-10 h.
In a second aspect, the invention provides a neodymium iron boron rare earth permanent magnet waste regenerated magnet prepared by the preparation method of the first aspect, and the neodymium iron boron rare earth permanent magnet waste regenerated magnet comprises main phase crystal grains formed by rare earth waste powder and an R-M alloy layer coated on the surfaces of the main phase crystal grains.
Compared with the prior art, the invention has the beneficial effects that:
in the invention, the waste materials are directly utilized to prepare the regenerated magnet by using the short-flow controllable preparation process, no new materials are required to be added, the recovery efficiency is greatly improved, the recovery cost is reduced, the introduction of chemical reagents is eliminated in the production process, the recovery process is more environment-friendly, the waste materials containing Ce are utilized in a large amount, and the problem of overstocking of the existing large amount of waste materials containing Ce is solved.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments.
Example 1
The embodiment provides a preparation method of a neodymium iron boron rare earth permanent magnet waste regenerated magnet, which specifically comprises the following steps:
(1) the mixed waste containing Ce and having the mark number of N35-N40 is distinguished from the mixed waste containing no Ce and having the mark number of N48-N52, and 5kg of the mixed waste is selected respectively. And removing oil stains and oxide scales on the surface of the two wastes by an acid pickling method, washing the acid-pickled wastes by a high-pressure water gun, drying the washed wastes, and putting the dried wastes into a glove box for storage. Wherein the pickling solution is hydrochloric acid with the concentration of 1%, and the surface treatment time is 15 s;
(2) respectively putting the waste materials obtained in the step (1) into a hydrogen breaking furnace, enabling the waste materials to absorb hydrogen under the hydrogen pressure environment of 0.1-0.2 MPa, heating the waste materials to 550 ℃ for dehydrogenation after the pressure in the hydrogen breaking furnace changes for 5 minutes and is less than 0.01MPa, cooling the waste materials after the vacuum degree in the furnace is less than 10Pa, and sieving coarse powder by a vibrating sieve, wherein the size of the sieve is 200 meshes, so that large waste materials and impurities in the coarse powder are sieved out;
(3) adding a lubricant and an antioxidant according to the proportion of 1mL/kg and 0.015% into the two hydrogen powders obtained in the step (2), mixing for 2 hours, and then respectively putting the mixture into an airflow mill for milling, wherein the particle size of the Ce-containing waste D50 is controlled to be 4.5 +/-0.2 microns, the rotating speed of a sorting wheel of the airflow mill is 4300r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during working, the working pressure is 0.6-0.65 MPa, the particle size of the Ce-free waste D50 is controlled to be 4.2 +/-0.2 microns, the rotating speed of the sorting wheel of the airflow mill is 4500r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during working, and the working pressure is 0.6-0.65 MPa;
(4) mixing the two fine powders obtained in the step (3) according to a mass ratio of 1: 1, adding neodymium copper alloy powder into the mixed fine powder according to 1.5 wt.% to uniformly mix the fine powder for 2 hours, and performing orientation compression by using a full-automatic forming press, wherein the oxygen content in the press is less than 10ppm and the blank density is more than 3.8g/cm during working3. And (3) placing the formed pressed blank into isostatic pressing after plastic packaging, keeping the pressure for 30s at 200MPa, taking out, removing the bag, and placing into a glove box for storage.
(5) And (3) placing the pressed blank subjected to isostatic pressing in the step (4) into a sintering furnace, preserving heat for 4 hours at 1045 ℃, preserving heat for 3 hours at 880 ℃ and preserving heat for 3 hours at 480 ℃ on the sintered magnet, and finishing secondary heat treatment.
And obtaining the Ce-containing neodymium iron boron rare earth permanent magnet waste regenerated magnet, wherein the content of rare earth in the neodymium iron boron rare earth permanent magnet waste regenerated magnet is 29.5-30.5 wt%, and the content of Ce accounts for 20-25 wt% of the total amount of rare earth.
Example 2
The embodiment provides a preparation method of a neodymium iron boron rare earth permanent magnet waste regenerated magnet, which specifically comprises the following steps:
(1) the mixed waste containing Ce and having the mark number of N35-N40 is distinguished from the mixed waste containing no Ce and having the mark number of N48-N52, and 5kg of the mixed waste is selected respectively. And removing oil stains and oxide scales on the surface of the two wastes by an acid pickling method, washing the acid-pickled wastes by a high-pressure water gun, drying the washed wastes, and putting the dried wastes into a glove box for storage. Wherein the pickling solution is hydrochloric acid with the concentration of 1%, and the surface treatment time is 15 s;
(2) respectively putting the waste materials obtained in the step (1) into a hydrogen breaking furnace, enabling the waste materials to absorb hydrogen under the hydrogen pressure environment of 0.1-0.2 MPa, heating the waste materials to 550 ℃ for dehydrogenation after the pressure in the hydrogen breaking furnace changes for 5 minutes and is less than 0.01MPa, cooling the waste materials after the vacuum degree in the furnace is less than 10Pa, and sieving coarse powder by a vibrating sieve, wherein the size of the sieve is 200 meshes, so that large waste materials and impurities in the coarse powder are sieved out;
(3) adding a lubricant and an antioxidant according to the proportion of 1.2mL/kg and 0.015% into the two hydrogen powders obtained in the step (2), mixing for 2 hours, and then respectively putting the mixture into an airflow mill for milling, wherein the particle size of Ce-containing waste D50 is controlled to be 4.2 +/-0.2 microns, the rotating speed of a sorting wheel of the airflow mill is 4500r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during work, the working pressure is 0.6-0.65 MPa, the particle size of Ce-free waste D50 is controlled to be 3.7 +/-0.2 microns, the rotating speed of the sorting wheel of the airflow mill is 5000r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during work, and the working pressure is 0.6-0.65 MPa;
(4) mixing the two fine powders obtained in the step (3) according to a mass ratio of 1: 2, proportioning, adding Nd-Al-Ga alloy powder into the mixed fine powder according to 1 wt.%, uniformly mixing the fine powder for 2 hours, and carrying out orientation compression by using a full-automatic forming press, wherein the oxygen content in the press is less than 10ppm, and the blank density is more than 3.8g/cm during working3. And (3) placing the formed pressed blank into isostatic pressing after plastic packaging, keeping the pressure for 30s at 200MPa, taking out, removing the bag, and placing into a glove box for storage.
(5) And (3) placing the pressed blank subjected to isostatic pressing in the step (4) into a sintering furnace, preserving heat for 4 hours at the temperature of 1055 ℃, preserving heat for 3 hours at the temperature of 890 ℃ and preserving heat for 3 hours at the temperature of 485 ℃ on the sintered magnet, and finishing secondary heat treatment.
And obtaining the Ce-containing neodymium iron boron rare earth permanent magnet waste regenerated magnet, wherein the content of rare earth in the neodymium iron boron rare earth permanent magnet waste regenerated magnet is 29.5-30.5 wt%, and the content of Ce accounts for 15-20 wt% of the total amount of rare earth.
Example 3
The embodiment provides a preparation method of a neodymium iron boron rare earth permanent magnet waste regenerated magnet, which specifically comprises the following steps:
(1) the mixed waste containing Ce and having the mark number of N35-N40 is distinguished from the mixed waste containing no Ce and having the mark number of N48-N52, and 5kg of the mixed waste is selected respectively. And removing oil stains and oxide scales on the surface of the two wastes by an acid pickling method, washing the acid-pickled wastes by a high-pressure water gun, drying the washed wastes, and putting the dried wastes into a glove box for storage. Wherein the pickling solution is hydrochloric acid with the concentration of 1%, and the surface treatment time is 15 s;
(2) respectively putting the waste materials obtained in the step (1) into a hydrogen breaking furnace, enabling the waste materials to absorb hydrogen under the hydrogen pressure environment of 0.1-0.2 MPa, heating the waste materials to 550 ℃ for dehydrogenation after the pressure in the hydrogen breaking furnace changes for 5 minutes and is less than 0.01MPa, cooling the waste materials after the vacuum degree in the furnace is less than 10Pa, and sieving coarse powder by a vibrating sieve, wherein the size of the sieve is 200 meshes, so that large waste materials and impurities in the coarse powder are sieved out;
(3) adding a lubricant and an antioxidant according to the proportion of 1.5mL/kg and 0.013% into the two hydrogen powders obtained in the step (2), mixing for 2 hours, and then respectively putting into an air flow mill for milling, wherein the particle size of Ce-containing waste D50 is controlled to be 4.2 +/-0.2 microns, the rotating speed of a sorting wheel of the air flow mill is 4000r/min, the internal oxygen content of the air flow mill is controlled to be below 1ppm during working, the working pressure is 0.6-0.65 MPa, the particle size of Ce-free waste D50 is controlled to be 3.7 +/-0.2 microns, the rotating speed of the sorting wheel of the air flow mill is 5000r/min, the internal oxygen content of the air flow mill is controlled to be below 1ppm during working, and the working pressure is 0.6-0.65 MPa;
(4) mixing the two fine powders obtained in the step (3) according to a mass ratio of 1: 3, proportioning, then adding Dy-Cu alloy powder into the mixed fine powder according to 1.5 wt.%, uniformly mixing the fine powder for 2 hours, and then orienting by a full-automatic forming pressProfiling, wherein the oxygen content in the press is less than 10ppm, and the density of the pressed blank is more than 3.8g/cm3. And (3) placing the formed pressed blank into isostatic pressing after plastic packaging, keeping the pressure for 30s at 200MPa, taking out, removing the bag, and placing into a glove box for storage.
(5) And (3) placing the pressed blank subjected to isostatic pressing in the step (4) into a sintering furnace, preserving heat for 3 hours at the temperature of 1057 ℃, preserving heat for 4 hours at the temperature of 860 ℃ and preserving heat for 5 hours at the temperature of 490 ℃ on the sintered magnet, and finishing secondary heat treatment.
And obtaining the Ce-containing neodymium iron boron rare earth permanent magnet waste regenerated magnet, wherein the content of rare earth in the neodymium iron boron rare earth permanent magnet waste regenerated magnet is 30.5-31.5 wt.%, and the content of Ce accounts for 10-15 wt.% of the total amount of rare earth.
Example 4
The embodiment provides a preparation method of a neodymium iron boron rare earth permanent magnet waste regenerated magnet, which specifically comprises the following steps:
(1) the mixed waste containing Ce and having the mark number of N35-N40 is distinguished from the mixed waste containing no Ce and having the mark number of N48-N52, and 5kg of the mixed waste is selected respectively. And removing oil stains and oxide scales on the surface of the two wastes by an acid pickling method, washing the acid-pickled wastes by a high-pressure water gun, drying the washed wastes, and putting the dried wastes into a glove box for storage. Wherein the pickling solution is hydrochloric acid with the concentration of 1%, and the surface treatment time is 15 s;
(2) respectively putting the waste materials obtained in the step (1) into a hydrogen breaking furnace, enabling the waste materials to absorb hydrogen under the hydrogen pressure environment of 0.1-0.2 MPa, heating the waste materials to 550 ℃ for dehydrogenation after the pressure in the hydrogen breaking furnace changes for 5 minutes and is less than 0.01MPa, cooling the waste materials after the vacuum degree in the furnace is less than 10Pa, and sieving coarse powder by a vibrating sieve, wherein the size of the sieve is 200 meshes, so that large waste materials and impurities in the coarse powder are sieved out;
(3) adding a lubricant and an antioxidant according to 1.4mL/kg and 0.013% into the two hydrogen powders obtained in the step (2), mixing for 2 hours, and then respectively putting into an airflow mill for milling, wherein the particle size of Ce-containing waste D50 is controlled to be 3.8 +/-0.2 microns, the rotating speed of a sorting wheel of the airflow mill is 4600r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during working, the working pressure is 0.6-0.65 MPa, the particle size of Ce-free waste D50 is controlled to be 3.5 +/-0.2 microns, the rotating speed of the sorting wheel of the airflow mill is 5300r/min, the internal oxygen content of the airflow mill is controlled to be below 1ppm during working, and the working pressure is 0.6-0.65 MPa;
(4) mixing the two fine powders obtained in the step (3) according to a mass ratio of 1: 4, proportioning, adding Dy-Cu-Ga alloy powder into the mixed fine powder according to 1.3 wt.%, uniformly mixing the fine powder for 2 hours, and carrying out orientation compression by using a full-automatic forming press, wherein the oxygen content in the press is less than 10ppm during working, and the blank density is more than 3.8g/cm3. And (3) placing the formed pressed blank into isostatic pressing after plastic packaging, keeping the pressure for 30s at 200MPa, taking out, removing the bag, and placing into a glove box for storage.
(5) And (3) placing the pressed blank subjected to isostatic pressing in the step (4) into a sintering furnace, preserving heat for 3.5 hours at 1060 ℃, preserving heat for 2 hours at 900 ℃ and preserving heat for 9 hours at 500 ℃ on the sintered magnet, and finishing secondary heat treatment.
And obtaining the Ce-containing neodymium iron boron rare earth permanent magnet waste regenerated magnet, wherein the content of rare earth in the neodymium iron boron rare earth permanent magnet waste regenerated magnet is 30.5-31.5 wt.%, and the content of Ce accounts for 5-10 wt.% of the total amount of rare earth.
Magnetic performance data of the regenerated magnets made from the Ce-containing neodymium iron boron rare earth permanent magnet waste materials prepared in the examples are detected and shown in table 1.
TABLE 1
As can be seen from the data in table 1:
(1) compared with example 1 and example 2, in example 4 and example 3, the magnetic performance data of example 2 and example 4 are obviously higher than those of example 1 and example 3. This is because the mass ratio of Ce-containing scrap powder in the rare earth scrap of example 2 and example 4 is lower than that of example 1 and example 3; meanwhile, the particle diameters of the rare earth scrap powders in the embodiments 2 and 4 are also lower than those in the embodiments 1 and 3, which is why the coercivity data of the magnets in the embodiments 2 and 4 are higher than those in the embodiments 1 and 3.
(2) The coercivity data of the regenerated magnets in examples 1, 2, 3 and 4 were slightly higher than those of the recycled scrap magnets of the same composition. This is because the monodispersed R-M alloy powders in examples 1, 2, 3, and 4 have high sphericity, and the coercivity of the magnet is improved by the double alloy addition into the grain boundary of the Ce-containing regenerated magnet. The reason is that the R-M with high sphericity enters the crystal boundary, so that the oxidation resistance of the crystal boundary is improved, and a core-shell structure of the R-M wrapping the main phase crystal grains is formed. The addition of R-M improves the grain boundary, reduces the exchange effect among grains, and simultaneously, the magnet has lower oxygen content, thus improving the coercive force.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. The preparation method of the neodymium iron boron rare earth permanent magnet waste regenerated magnet is characterized by comprising the following steps:
and mixing the rare earth waste powder with the R-M alloy powder to obtain mixed fine powder, and sequentially carrying out molding, sintering and heat treatment on the mixed fine powder to obtain the neodymium iron boron rare earth permanent magnet waste regenerated magnet.
2. The method according to claim 1, wherein R of the R-M alloy powder is any one of Pr, Nd, Ho, Dy, or Tb, and M is any one or a combination of at least two of Cu, Al, and Ga;
preferably, the grain diameter of the R-M alloy powder is 30-100 mu M;
preferably, the sphericity of the R-M alloy powder is 85-95%.
3. The production method according to claim 1 or 2, characterized in that the R-M alloy powder is produced by a droplet-by-droplet gas atomization method;
preferably, the droplet-by-droplet aerosolization process specifically comprises the steps of:
the R and M metals are melted completely and insulated through induction melting, a small hole is formed in the bottom of a melting crucible, piezoelectric ceramics are driven to vibrate through pulse signals, and R-M alloy liquid is extruded to flow out of the small hole in the bottom of the crucible in a small liquid drop mode, so that R-M alloy powder is obtained.
4. The method according to any one of claims 1 to 3, wherein the rare earth scrap powder is prepared by the following method:
classifying and recycling rare earth waste, and then sequentially carrying out acid washing, washing and drying, hydrogen crushing, screening and grinding to obtain rare earth waste powder;
preferably, the rare earth waste comprises Ce-containing rare earth waste and Ce-free rare earth waste;
preferably, the mass ratio of the Ce-containing waste powder to the Ce-free waste powder is 1: (1-4);
preferably, the particle size of the rare earth waste powder is 3-5 μm.
5. The production method according to any one of claims 1 to 4, wherein the hydrogen decrepitation process is performed in a hydrogen decrepitation furnace;
preferably, the pressure of the hydrogen absorption reaction in the hydrogen crushing process is 0.1-0.2 MPa;
preferably, the temperature of the dehydrogenation reaction in the hydrogen crushing process is 500-600 ℃;
preferably, the screening process is performed in a vibrating screen.
6. The production method according to any one of claims 1 to 5, wherein a lubricant and an antioxidant are added to the rare earth scrap during grinding;
preferably, the addition amount of the lubricant is 1-1.5 mL/kg;
preferably, the addition amount of the antioxidant is 0.01-0.015 wt.% based on 100 wt.% of the rare earth waste;
preferably, the milling process is carried out in a jet mill;
preferably, the rotating speed of a sorting wheel of the jet mill is 4000-5500 r/min;
preferably, the internal oxygen content of the jet mill is less than or equal to 1ppm when the jet mill works;
preferably, the working pressure of the air flow mill is 0.6-0.65 MPa.
7. The production method according to any one of claims 1 to 6, characterized in that the amount of the R-M alloy powder added is 1 to 2 wt.% based on 100 wt.% of the mass of the rare earth scrap powder;
preferably, the mixing time is 1-2 h.
8. The method according to any one of claims 1 to 7, wherein the molding process of the mixed fine powder is performed in a fully automatic molding press and an isostatic press;
preferably, the central orientation magnetic field of the shaping process is > 2T;
preferably, the oxygen content of the shaping process is < 10 ppm;
preferably, the density of the pressed blank after the mixed fine powder is formed is more than 3.8g/cm3；
Preferably, the holding pressure of the isostatic pressing process is 200-250 MPa;
preferably, the pressure maintaining time of the isostatic pressing process is 30-60 s;
preferably, the density of the pressed blank after isostatic pressing is more than 4.1g/cm3。
9. The production method according to any one of claims 1 to 8, wherein the sintering and the heat treatment are both performed in a sintering furnace;
preferably, the temperature of the sintering process is 1000-1060 ℃;
preferably, the temperature holding time in the sintering process is 3-5 h;
preferably, the heat treatment process is a secondary heat treatment, the temperature of the primary heat treatment is 800-900 ℃, and the temperature of the secondary heat treatment is 450-550 ℃;
preferably, the temperature holding time of the heat treatment process is 3-10 h.
10. The neodymium-iron-boron rare earth permanent magnet waste regenerated magnet prepared by the preparation method of any one of claims 1 to 9 is characterized by comprising main phase crystal grains formed by rare earth waste powder and an R-M alloy layer coated on the surfaces of the main phase crystal grains.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2009137983A1 (en) * | 2008-05-15 | 2009-11-19 | 三环瓦克华（北京）磁性器件有限公司 | Sintered ndfeb rare earth permanent magnetic material and its manufacturing method |
| CN103093914A (en) * | 2013-01-25 | 2013-05-08 | 宁波同创强磁材料有限公司 | High-performance neodymium-iron-boron magnet and preparation method thereof |
| CN109093128A (en) * | 2018-09-25 | 2018-12-28 | 大连理工大学 | A kind of device and method preparing superfine low melting point globular metallic powder by drop atomization |
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009137983A1 (en) * | 2008-05-15 | 2009-11-19 | 三环瓦克华（北京）磁性器件有限公司 | Sintered ndfeb rare earth permanent magnetic material and its manufacturing method |
| CN103093914A (en) * | 2013-01-25 | 2013-05-08 | 宁波同创强磁材料有限公司 | High-performance neodymium-iron-boron magnet and preparation method thereof |
| CN109093128A (en) * | 2018-09-25 | 2018-12-28 | 大连理工大学 | A kind of device and method preparing superfine low melting point globular metallic powder by drop atomization |
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