A method for efficiently preparing regenerated rfeb magnetic powder from rfeb-based oil sludge waste

Abstract

The present application belongs to the technical field of regenerating magnetic powder, and relates to a method for efficiently preparing regenerated RFeB magnetic powder from RFeB oil sludge waste. The present application discloses a method for efficiently preparing regenerated RFeB magnetic powder from RFeB oil sludge waste, wherein R is one or more of rare earth elements; the method comprises the following steps: mixing the purified RFeB oil sludge with a reducing medium, and then placing the mixture in a vacuum rotary furnace into which inert gas is introduced, rotating and heating at a first temperature of 70-150 DEG C, adjusting the vacuum degree, performing first-stage reduction treatment at a second temperature of 600-890 DEG C, and performing second-stage diffusion treatment at a third temperature of 900-1100 DEG C to obtain an alloy ingot, and then powdering to obtain regenerated RFeB magnetic powder. The method for efficiently preparing regenerated RFeB magnetic powder from RFeB oil sludge waste can regenerate the oil sludge type waste generated in the process of processing rare earth functional materials, and the regeneration efficiency of rare earth elements can be more than 80%.

Description

Technical Field

[0001] This invention belongs to the field of regenerated magnetic powder technology, and relates to a method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste. Background Technology

[0002] Besides primary minerals, renewable rare earth functional materials, such as RFeB-type materials (where R represents one or more rare earth elements), generate a large amount of waste during production and processing. This waste includes powders and small lumps from raw material preparation, slag residue from alloy smelting, ultrafine powder and heavily oxidized powder from powdering, slightly oxidized lumps from sintering, cutting blocks, scraps, magnetic chips, low-performance magnets, substandard products from surface treatment, sludge, and pre-plating treatments such as chamfering and pickling solutions. Secondary recycling of these materials will become a more important source of raw materials for rare earth resources. Among these, R-type sludge waste, mainly composed of lubricating oil and coolant used in cutting and grinding processes, and cleaning agents used in cleaning processes combined with other waste, accounts for 35-50% of the total waste. This results in a serious waste of rare earth resources, and the long-term accumulation of sludge waste causes severe environmental pollution.

[0003] Currently, the main methods for recycling RFeB-type oily sludge waste are wet and pyrometallurgical processes. These methods involve long processing times, large quantities of chemical reagents, high energy consumption, and significant pollution. The recovered products are rare earth oxides, which have low added value, significant compositional variations, and unstable performance, placing them at the low to mid-end of the value chain. Furthermore, separation generates approximately 70% solid waste of metal oxides such as Fe, Co, and Al, resulting in substantial resource waste. Therefore, there is a need to develop efficient processing technologies for the recycling of rare earth resources. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste. The method involves mixing purified RFeB-type oily sludge with a reducing medium, followed by rotary heating, primary reduction treatment, and secondary diffusion treatment to obtain high-performance regenerated RFeB magnetic powder.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for efficiently producing recycled RFeB magnetic powder from RFeB-type oily sludge waste, wherein R is one or more rare earth elements; the method includes: mixing purified RFeB-type oily sludge with a reducing medium, placing it in a vacuum rotary furnace with an inert gas, rotating and heating it at a first temperature of 70-150°C, adjusting the vacuum degree, performing a first-stage reduction treatment at a second temperature of 600-890°C, and performing a second-stage diffusion treatment at a third temperature of 900-1100°C to obtain an alloy ingot, and then grinding it into powder to obtain recycled RFeB magnetic powder.

[0007] Preferably, the mass ratio of the purified RFeB-type sludge to the reducing medium is (1-30):1.

[0008] Further preferably, the mass ratio of the purified RFeB-type sludge to the reducing medium is (6-19):1.

[0009] Preferably, the reducing medium includes one or more of calcium hydride, calcium granules, calcium chloride, and sodium borohydride.

[0010] Further preferably, when the reducing medium is calcium hydride, the mass ratio of the purified RFeB-type sludge to the reducing medium is (11-19):1.

[0011] Further preferably, when the reducing medium is calcium particles, the mass ratio of the purified RFeB-type sludge to the reducing medium is (6-9):1.

[0012] Preferably, the rotation speed of the vacuum rotary furnace is 50 to 500 revolutions per minute.

[0013] Preferably, the rotary heating includes: rotary heating at a first temperature of 80-100°C for 1-300 minutes.

[0014] Preferably, the primary reduction process includes: holding at a second temperature of 700–890°C for 1–300 minutes, with a heating rate of 1–20°C / minute.

[0015] Further preferably, the primary reduction process includes: maintaining a second temperature of 780–850°C for 30–60 minutes, with a heating rate of 5–10°C / minute.

[0016] More preferably, the primary reduction process includes: maintaining a temperature of 800–850°C for 30–60 minutes.

[0017] Preferably, the secondary diffusion treatment includes: maintaining a temperature of 910–1100°C at a third temperature for 100–1000 minutes, with a heating rate of 1–20°C / minute.

[0018] Further preferably, the secondary diffusion treatment includes: maintaining a temperature of 950–1080°C for 300–480 minutes.

[0019] More preferably, the secondary diffusion treatment includes: maintaining a temperature of 1020–1040°C for 300–480 minutes.

[0020] Preferably, the pressure of the upper pressure valve of the vacuum rotary furnace is 0.001 to 1 MPa.

[0021] Preferably, the powder preparation includes: crushing the alloy ingot and grinding it into RFeB powder by air jet milling; mixing and cleaning the RFeB powder with a cleaning solution to obtain RFeB magnetic powder after impurity removal; and degassing, activating and drying the RFeB magnetic powder to obtain regenerated RFeB magnetic powder.

[0022] More preferably, the impurity removal cleaning solution contains 0.1 to 10 wt% acetic acid.

[0023] More preferably, the impurity removal cleaning solution comprises acetic acid, water, and anhydrous ethanol in a volume ratio of (1-5):(8-20):100.

[0024] More preferably, the impurity removal cleaning solution contains 0.5 to 5 wt% acetic acid.

[0025] More preferably, the impurity removal cleaning solution comprises acetic acid, water, and anhydrous ethanol in a volume ratio of (1-2.5):10:100.

[0026] Further preferably, the average particle size of the air-jet milled RFeB powder is 1–10 μm.

[0027] More preferably, the average particle size of the air-jet milled RFeB powder is 2–5 μm.

[0028] More preferably, the mass ratio of the air jet mill RFeB powder to the impurity removal cleaning liquid is 1:(10-200).

[0029] More preferably, the mass ratio of the air jet mill RFeB powder to the impurity removal cleaning liquid is 1:(20-50).

[0030] Further preferably, the degassing and activation drying includes: loading the impurity-removed RFeB magnetic powder into a rotary furnace through which hydrogen is continuously introduced, setting the rotary furnace heating rate to 1-10°C / min, the heating temperature to 180-400°C, holding the temperature for 10-600 minutes, and setting the pressure of the upper pressure valve of the rotary furnace body to 0.001-0.1MPa.

[0031] Preferably, the method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste includes: mixing purified RFeB-type oily sludge with a reducing medium, placing it in a vacuum rotary furnace with an inert gas atmosphere, rotating and heating it at a first temperature of 70-150°C, and adjusting the vacuum degree of the rotary furnace to 10. -4 ~10 -1Pa is subjected to a first-stage reduction treatment at a second temperature of 600–890℃, followed by a second-stage diffusion treatment at a third temperature of 900–1100℃. After cooling, an alloy ingot is obtained. The alloy ingot is crushed and then subjected to air jet milling to produce RFeB powder. The RFeB powder is then mixed with a cleaning solution to obtain purified RFeB magnetic powder. The purified RFeB magnetic powder is then degassed, activated, and dried to obtain regenerated RFeB magnetic powder.

[0032] Further preferably, the RFeB powder from the air jet mill is mixed and cleaned with the impurity removal cleaning solution 1 to 6 times.

[0033] More preferably, the RFeB powder from the air jet mill is mixed and cleaned with the impurity removal cleaning solution 2 to 5 times.

[0034] Preferably, the purified RFeB-type sludge is obtained by purifying RFeB-type sludge waste.

[0035] Preferably, the purification includes separating RFeB-type oily sludge powder from the RFeB-type oily sludge waste using physical and / or chemical methods.

[0036] Preferably, the purification includes: drying the RFeB type oily sludge waste and mixing it with a diluent, then filtering the bottom oily sludge material and subjecting it to two-stage baking; the two-stage baking includes baking in an inert gas at 100-300°C for the first time and baking at 300-500°C for the second time.

[0037] Preferably, the purification includes: placing the pretreated RFeB type oily sludge waste in a vacuum rotary furnace with inert gas introduced, and purifying it once at 100-300°C;

[0038] When the vacuum degree of the vacuum rotary furnace reaches the set threshold, purified gas is introduced into the vacuum rotary furnace to perform secondary purification of the RFeB type oily sludge waste after the first purification at 300-500°C.

[0039] Further preferably, the pretreatment of the RFeB type oily sludge waste includes one or more of drying, activation, and pre-purification.

[0040] More preferably, the activation includes: adding the dried RFeB-type oily sludge waste and diluent into the oily sludge mixing and filtering device and stirring, so that the dried RFeB-type oily sludge waste and diluent are in full contact to achieve activation;

[0041] And / or, the pre-purification includes: centrifuging and baking the activated RFeB-type oily sludge waste to achieve pre-purification.

[0042] More preferably, the diluent comprises two or more of the following: 60-95% alcohol compounds, 5-80% ketone or ester compounds, 5-10% petroleum derivatives, and 5-40% weak alkaline solution.

[0043] Further preferably, the primary purification includes: raising the temperature of the vacuum rotary furnace and introducing inert gas into the vacuum rotary furnace until the temperature of the vacuum rotary furnace stabilizes at 100-300°C; continuously introducing inert gas for 30-120 minutes, so as to purify the pretreated RFeB type oil sludge waste in the primary purification.

[0044] Further preferably, the secondary purification includes: evacuating the vacuum rotary furnace until the vacuum level inside the vacuum rotary furnace reaches a set threshold, and setting the pressure of the pressure limiting valve of the vacuum rotary furnace to 1-2 atm; raising the temperature of the vacuum rotary furnace and introducing purified gas into the vacuum rotary furnace until the temperature of the vacuum rotary furnace stabilizes at 300-500°C; and continuously introducing purified gas for 60-120 minutes to allow the RFeB type oily sludge waste purified in the first step to undergo secondary purification.

[0045] Further preferred, the purified gas is a mixture of hydrogen and inert gas, wherein the volume ratio of hydrogen to inert gas is 20:80 to 50:50, and the flow rate of the purified gas is 30 to 70 mL / min.

[0046] A regenerated RFeB magnetic powder with a purity of ≥99.5%.

[0047] As a preferred option, the total rare earth element retention rate of the regenerated RFeB magnetic powder is ≥82% compared with that of purified RFeB sludge.

[0048] Preferably, the saturation magnetization of the regenerated RFeB magnetic powder is ≥90 emu / g, and the coercivity is ≥9000 Oe.

[0049] Further optimization yields regenerated RFeB magnetic powder with a saturation magnetization ≥100 emu / g and a coercivity ≥10000 Oe.

[0050] A regenerated RFeB magnet comprising 0.1 to 100 wt% regenerated RFeB magnetic powder.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention can regenerate oily sludge waste generated during the processing of rare earth functional materials, especially heavily oxidized oily sludge with high impurity content and complex composition such as wire cutting and water-based slicing. The rare earth element regeneration efficiency can exceed 80%.

[0053] 2. In the method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention, purified RFeB-type oily sludge is used, and high-performance regenerated RFeB magnetic powder is obtained by combining primary reduction treatment and secondary diffusion treatment.

[0054] 3. In the method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention, the mixed powder after air jet milling is cleaned with a cleaning solution, and the total loss rate of rare earth elements is ≤10%, which effectively improves the magnetic properties of the regenerated RFeB magnetic powder.

[0055] 4. The solvents in the cleaning solution of the present invention are mostly water and alcohols. The low content of acetic acid can be neutralized and degraded and directly discharged, without causing pollution to the environment.

[0056] 5. The method for efficiently preparing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention yields regenerated RFeB magnetic powder with high purity and impurity content of less than 0.5%.

[0057] 6. The method for efficiently preparing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention results in a significant improvement in the saturation magnetization and coercivity of the obtained regenerated RFeB magnetic powder.

[0058] 7. The method for efficiently preparing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention recovers valuable elements in the form of magnetic powder, with higher recovery efficiency, and is suitable for the recycling of batches of oily sludge waste. Detailed Implementation

[0059] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0060] Unless otherwise specified, the materials used in this invention are commercially available products, and the methods used are conventional technical means.

[0061] In this article, the RFeB type oily sludge waste originated from rare earth magnet processing enterprises.

[0062] In this paper, the purified RFeB-type sludge was prepared by the purification method described in the Chinese patent text (publication number: CN118389859A).

[0063] In this document, the purified RFeB sludge in the examples was prepared according to any of the purification methods described in Examples 1 to 20 of Chinese Patent Text (Publication No.: CN118389859A).

[0064] This paper describes a method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste, including:

[0065] (1) The purified RFeB-type sludge was mixed with the reducing medium at a mass ratio of (1-30):1;

[0066] (2) Then put it into a mixing tank with a stirring speed of 50 to 500 rpm, a mixing time of 1 to 600 minutes, and a stirring speed of 60 to 500 rpm;

[0067] (3) After mixing is completed, transfer the material to a rotary furnace with a rotation speed of 50 to 500 rpm, a heating temperature of 70 to 150°C, and a time of 1 to 300 minutes.

[0068] (4) While heating, turn on the secondary vacuum pump system until the pressure reaches 10. -4 ~10 -1 At Pa, the rotary furnace heating rate is set to 1-20℃ / min, the temperature is raised to the second temperature of 600-890℃, and held for 1-300 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 900-1100℃, held for 100-1000 minutes for secondary diffusion treatment, and the pressure of the upper pressure valve of the rotary furnace is controlled at 0.01-0.1MPa.

[0069] (5) After diffusion treatment, open the exhaust port of the rotary furnace and increase the flow rate of inert gas at the inlet end to rapidly cool the alloy ingot. When the temperature inside the furnace is below 100°C, fill the furnace with inert gas to 0.001-0.1 MPa and maintain the pressure. Then cool it to room temperature to obtain the cooled alloy ingot.

[0070] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100-200 μm. Then it is ground into RFeB powder with an average particle size of 1-10 μm by an air jet mill under a nitrogen atmosphere.

[0071] (7) Prepare a cleaning solution by mixing acetic acid, water and anhydrous ethanol in a volume ratio of (1-5):(8-20):100;

[0072] (8) Load the air jet mill RFeB powder and the impurity removal cleaning solution into the cleaner at a mass ratio of 1:(10-200);

[0073] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 50-200Hz, clean for 1-60 seconds, let the mixture stand for 0.1-10 minutes after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat several times; then wash with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0074] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously circulates hydrogen. The rotary furnace is set to a heating rate of 1-10℃ / min, a heating temperature of 180-400℃, and a holding time of 10-600 minutes for degassing, activation and drying treatment. The pressure of the upper pressure valve of the rotary furnace body is set to 0.001-0.1MPa to obtain regenerated RFeB magnetic powder.

[0075] (11) The regenerated RFeB magnetic powder is ball-milled, sieved, mixed with AB glue, and then cured and oriented under a magnetic field of 1-5T; the magnetic properties of the regenerated RFeB magnetic powder are tested by a magnetic measuring instrument.

[0076] In this paper, compared with the original RFeB type oil sludge waste, the total rare earth element regeneration rate of the recycled RFeB magnetic powder is ≥80%.

[0077] In this paper, compared with the purified RFeB sludge, the total rare earth element regeneration rate of the regenerated RFeB magnetic powder is ≥82%; and the total rare earth element regeneration rate can reach 92%.

[0078] In this paper, the total loss rate of rare earth elements before and after impurity removal of regenerated RFeB magnetic powder is ≤10%.

[0079] In this paper, the purity of the regenerated RFeB magnetic powder is ≥99.5%.

[0080] In this paper, the saturation magnetization of the regenerated RFeB magnetic powder is ≥90 emu / g; the coercivity is ≥9000 Oe.

[0081] In this paper, the RFeB-type oily sludge waste was purified according to the physical and / or chemical methods in the prior art, and then the regenerated RFeB magnetic powder obtained by the method of efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to the present invention also showed improved performance.

[0082] Example 1

[0083] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 19:1.

[0084] (2) Then put it into a mixing tank with a stirring speed of 150 rpm, a mixing time of 60 minutes, and a stirring speed of 100 rpm;

[0085] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 60 rpm, a heating temperature of 100℃, and a time of 30 minutes;

[0086] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.02MPa.

[0087] (5) After diffusion treatment, open the exhaust port at the outlet of the rotary furnace and increase the argon flow rate at the inlet to 0.01MPa. Rapidly cool the alloy ingot after reaction. When the temperature inside the furnace is below 100℃, fill the furnace with argon to 0.01MPa and maintain the pressure. When the rotary furnace is cooled to room temperature of 30-40℃, the cooled alloy ingot is obtained.

[0088] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 200 μm. Then it is ground into RFeB powder with an average particle size of 5 μm by an air jet mill under a nitrogen atmosphere.

[0089] (7) Mix acetic acid, deionized water and anhydrous ethanol in a volume ratio of 2.5:10:100 to prepare a cleaning solution for removing impurities;

[0090] (8) Load the air jet mill RFeB powder and the impurity removal cleaning solution into the cleaner at a mass ratio of 1:20;

[0091] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 5 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0092] (10) The purified RFeB magnetic powder is put back into the rotary furnace with hydrogen continuously introduced. The rotary furnace heating rate is set to 5℃ / minute, the heating temperature is 200℃, and the holding time is 60 minutes. Degassing, activation and drying are performed. The pressure of the upper pressure valve of the rotary furnace body is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0093] (11) Load the recycled RFeB magnetic powder into the ball mill jar with a ball-to-material ratio of 10:1, set the rotation speed to 50 rpm, and the ball milling time to 2 hours; after ball milling, pass it through an 800-mesh stainless steel screen; mix the recycled RFeB magnetic powder and AB glue at a ratio of 1:2 (mass ratio), and then cure and orient it under a 3T magnetic field; after curing, test the magnetic properties of the recycled RFeB magnetic powder with a magnetic measuring instrument.

[0094] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0095] Example 2

[0096] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 17:1.

[0097] (2) Then put it into a mixing tank with a stirring speed of 120 rpm, a mixing time of 40 minutes, and a stirring speed of 100 rpm;

[0098] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 60 rpm, a heating temperature of 100℃, and a time of 40 minutes;

[0099] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.04MPa.

[0100] (5) Same as step (5) in Example 1;

[0101] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 150 μm. Then it is ground into RFeB powder with an average particle size of 4.9 μm by an air jet mill under a nitrogen atmosphere.

[0102] (7) Mix acetic acid, deionized water and anhydrous ethanol in a volume ratio of 2:10:100 to prepare a cleaning solution for removing impurities;

[0103] (8) Same as step (8) in Example 1;

[0104] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 4 times; wash again with anhydrous ethanol to obtain the impurity-removed RFeB magnetic powder.

[0105] (10) is the same as step (10) in Example 1;

[0106] (11) is the same as step (11) in Example 1;

[0107] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0108] Example 3

[0109] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 15:1.

[0110] (2) Then put it into a mixing tank with a stirring speed of 150 rpm, a mixing time of 50 minutes, and a stirring speed of 150 rpm;

[0111] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 40 minutes;

[0112] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.04MPa.

[0113] (5) Same as step (5) in Example 1;

[0114] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 150 μm. Then it is ground into RFeB powder with an average particle size of 4.1 μm by an air jet mill under a nitrogen atmosphere.

[0115] (7) Same as step (7) in Example 2;

[0116] (8) Same as step (8) in Example 1;

[0117] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0118] (10) is the same as step (10) in Example 1;

[0119] (11) is the same as step (11) in Example 1;

[0120] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0121] Example 4

[0122] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 13:1.

[0123] (2) Load into a mixing tank with a stirring speed of 60 rpm, mixing time of 50 minutes, and stirring speed of 150 rpm.

[0124] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 50 minutes;

[0125] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1000℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.04MPa.

[0126] (5) Same as step (5) in Example 1;

[0127] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 4.1 μm by an air jet mill under a nitrogen atmosphere.

[0128] (7) Same as step (7) in Example 2;

[0129] (8) Load the RFeB powder from the air jet mill and the impurity removal cleaning solution into the cleaner at a mass ratio of 1:40;

[0130] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0131] (10) is the same as step (10) in Example 1;

[0132] (11) is the same as step (11) in Example 1;

[0133] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0134] Example 5

[0135] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 11:1;

[0136] (2) Then load it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 30 minutes, and a stirring speed of 150 rpm.

[0137] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0138] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 780℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1000℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.04MPa.

[0139] (5) Same as step (5) in Example 1;

[0140] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0141] (7) Mix acetic acid, deionized water and anhydrous ethanol in a volume ratio of 1:10:100 to prepare a cleaning solution for removing impurities;

[0142] (8) Same as step (8) in Example 4;

[0143] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the impurity-free RFeB magnetic powder.

[0144] (10) is the same as step (10) in Example 1;

[0145] (11) Same as step (7) in Example 1.

[0146] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0147] Example 6

[0148] (1) Same as step (1) in Example 1;

[0149] (2) Then it is loaded into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 180 rpm.

[0150] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 150 rpm, a heating temperature of 100℃, and a time of 50 minutes.

[0151] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.02MPa.

[0152] (5) Same as step (5) in Example 1;

[0153] (6) Same as step (6) in Example 3;

[0154] (7) Same as step (7) in Example 2;

[0155] (8) Load the RFeB powder from the air jet mill and the impurity removal cleaning solution into the cleaner at a mass ratio of 1:30;

[0156] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0157] (10) The purified RFeB magnetic powder is put back into the rotary furnace with hydrogen continuously introduced. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 250℃, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace body is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0158] (11) is the same as step (11) in Example 1.

[0159] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0160] Example 7

[0161] (1) Same as step (1) in Example 2;

[0162] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 150 rpm;

[0163] (3) Same as step (3) in Example 1;

[0164] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0165] (5) Same as step (5) in Example 1;

[0166] (6) Same as step (6) in Example 4;

[0167] (7) Same as step (7) in Example 2;

[0168] (8) Same as step (8) in Example 4;

[0169] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 50 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 5 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0170] (10) is the same as step (10) in Example 6;

[0171] (11) is the same as step (11) in Example 1.

[0172] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0173] Example 8

[0174] (1) Same as step (1) in Example 3;

[0175] (2) Then it is loaded into a mixing tank with a stirring speed of 80 rpm, a mixing time of 50 minutes, and a stirring speed of 150 rpm.

[0176] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 100℃, and a time of 40 minutes.

[0177] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0178] (5) Same as step (5) in Example 1;

[0179] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 3.5 μm by an air jet mill under a nitrogen atmosphere.

[0180] (7) Same as step (7) in Example 2;

[0181] (8) Same as step (8) in Example 4;

[0182] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 60 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0183] (10) is the same as step (10) in Example 1;

[0184] (11) is the same as step (11) in Example 1.

[0185] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0186] Example 9

[0187] (1) Same as step (1) in Example 4;

[0188] (2) Then it is loaded into a mixing tank with a stirring speed of 80 rpm, a mixing time of 50 minutes, and a stirring speed of 150 rpm.

[0189] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 100℃, and a time of 40 minutes.

[0190] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0191] (5) Same as step (5) in Example 1;

[0192] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 110 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0193] (7) Same as step (7) in Example 5;

[0194] (8) Load the RFeB powder from the air jet mill and the impurity removal cleaning solution into the cleaner at a mass ratio of 1:50;

[0195] (9) is the same as step (9) in Example 5;

[0196] (10) is the same as step (10) in Example 6;

[0197] (11) is the same as step (11) in Example 1.

[0198] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0199] Example 10

[0200] (1) Same as step (1) in Example 5;

[0201] (2) Then load it into a mixing tank with a stirring speed of 120 rpm, a mixing time of 50 minutes, and a stirring speed of 150 rpm.

[0202] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 80℃, and a time of 50 minutes;

[0203] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0204] (5) Same as step (5) in Example 1;

[0205] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 110 μm. Then it is ground into RFeB powder with an average particle size of 3.1 μm by an air jet mill under a nitrogen atmosphere.

[0206] (7) Same as step (7) in Example 5;

[0207] (8) Same as step (8) in Example 3;

[0208] (9) is the same as step (9) in Example 3;

[0209] (10) is the same as step (10) in Example 6;

[0210] (11) is the same as step (11) in Example 1.

[0211] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0212] Example 11

[0213] (1) Same as step (1) in Example 1;

[0214] (2) Then it is loaded into a mixing tank with a stirring speed of 110 rpm, a mixing time of 60 minutes, and a stirring speed of 200 rpm.

[0215] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 120 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0216] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0217] (5) Same as step (5) in Example 1;

[0218] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 3.5 μm by an air jet mill under a nitrogen atmosphere.

[0219] (7) Same as step (7) in Example 5;

[0220] (8) Same as step (8) in Example 4;

[0221] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 60 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0222] (10) The purified RFeB magnetic powder is put back into the rotary furnace with hydrogen continuously introduced. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 300℃, and a holding time of 30 minutes to carry out degassing, activation and drying treatment. The pressure of the upper pressure valve of the rotary furnace body is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0223] (11) is the same as step (11) in Example 1.

[0224] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0225] Example 12

[0226] (1) Same as step (1) in Example 2;

[0227] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 50 minutes, and a stirring speed of 180 rpm.

[0228] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 120 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0229] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0230] (5) Same as step (5) in Example 1;

[0231] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0232] (7) Mix acetic acid, deionized water and anhydrous ethanol in a volume ratio of 1.5:10:100 to prepare a cleaning solution for removing impurities;

[0233] (8) Same as step (8) in Example 9;

[0234] (9) is the same as step (9) in Example 5;

[0235] (10) The purified RFeB magnetic powder is put back into the rotary furnace with hydrogen continuously introduced. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 300℃, and a holding time of 30 minutes to carry out degassing, activation and drying treatment. The pressure of the upper pressure valve of the rotary furnace body is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0236] (11) is the same as step (11) in Example 1.

[0237] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0238] Example 13

[0239] (1) Same as step (1) in Example 3;

[0240] (2) Then it is loaded into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 180 rpm.

[0241] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 120 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0242] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 400 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0243] (5) Same as step (5) in Example 1;

[0244] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0245] (7) Same as step (7) in Example 12;

[0246] (8) Same as step (8) in Example 6;

[0247] (9) is the same as step (9) in Example 3;

[0248] (10) is the same as step (10) in Example 11;

[0249] (11) is the same as step (11) in Example 1.

[0250] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0251] Example 14

[0252] (1) Same as step (1) in Example 4;

[0253] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 150 rpm;

[0254] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 100 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0255] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 810℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0256] (5) Same as step (5) in Example 1;

[0257] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0258] (7) Same as step (7) in Example 12;

[0259] (8) Same as step (8) in Example 3;

[0260] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0261] (10) is the same as step (10) in Example 1;

[0262] (11) is the same as step (11) in Example 1.

[0263] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0264] Example 15

[0265] (1) Same as step (1) in Example 5;

[0266] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 150 rpm;

[0267] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 100 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0268] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0269] (5) Same as step (5) in Example 1;

[0270] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0271] (7) Same as step (7) in Example 12;

[0272] (8) Same as step (8) in Example 9;

[0273] (9) is the same as step (9) in Example 5;

[0274] (10) is the same as step (10) in Example 11;

[0275] (11) is the same as step (11) in Example 1.

[0276] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0277] Example 16

[0278] (1) Weigh the purified RFeB type sludge and mix it with calcium particles of the reducing medium at a mass ratio of 9:1.

[0279] (2) Then put it into a mixing tank with a stirring speed of 150 rpm, a mixing time of 60 minutes, and a stirring speed of 100 rpm;

[0280] (3) Same as step (3) in Example 1;

[0281] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1040℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0282] (5) Same as step (5) in Example 1;

[0283] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 150 μm. Then it is ground into RFeB powder with an average particle size of 4.2 μm by an air jet mill under a nitrogen atmosphere.

[0284] (7) Same as step (7) in Example 2;

[0285] (8) Same as step (8) in Example 1;

[0286] (9) is the same as step (9) in Example 1;

[0287] (10) is the same as step (10) in Example 1;

[0288] (11) is the same as step (11) in Example 1.

[0289] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0290] Example 17

[0291] (1) Weigh the purified RFeB type sludge and mix it with calcium particles of the reducing medium at a mass ratio of 8:1.

[0292] (2) Then put it into a mixing tank with a stirring speed of 120 rpm, a mixing time of 60 minutes, and a stirring speed of 100 rpm;

[0293] (3) Same as step (3) in Example 1;

[0294] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1040℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0295] (5) Same as step (5) in Example 1;

[0296] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 130 μm. Then it is ground into RFeB powder with an average particle size of 3.8 μm by an air jet mill under a nitrogen atmosphere.

[0297] (7) Same as step (7) in Example 2;

[0298] (8) Step (8) in Example 9 is the same;

[0299] (9) is the same as step (9) in Example 2;

[0300] (10) is the same as step (10) in Example 1;

[0301] (11) is the same as step (11) in Example 1.

[0302] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0303] Example 18

[0304] (1) Weigh the purified RFeB type sludge and mix it with calcium particles of the reducing medium at a mass ratio of 7:1.

[0305] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 100 rpm;

[0306] (3) Same as step (3) in Example 1;

[0307] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1040℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0308] (5) Same as step (5) in Example 1;

[0309] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 4.1 μm by an air jet mill under a nitrogen atmosphere.

[0310] (7) Same as step (7) in Example 2;

[0311] (8) Same as step (8) in Example 3;

[0312] (9) is the same as step (9) in Example 3;

[0313] (10) is the same as step (10) in Example 1;

[0314] (11) is the same as step (11) in Example 1.

[0315] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0316] Example 19

[0317] (1) Weigh the purified RFeB type sludge and mix it with calcium particles of the reducing medium at a mass ratio of 6:1.

[0318] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 60 minutes, and a stirring speed of 100 rpm;

[0319] (3) Same as step (3) in Example 1;

[0320] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 800℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1040℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0321] (5) Same as step (5) in Example 1;

[0322] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm, and then ground into powder with an average particle size of 4.1 μm by air jet mill under nitrogen atmosphere.

[0323] (7) Same as step (7) in Example 2;

[0324] (8) Same as step (8) in Example 9;

[0325] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0326] (10) is the same as step (10) in Example 1;

[0327] (11) is the same as step (11) in Example 1.

[0328] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0329] Example 20

[0330] (1) Same as step (1) in Example 16;

[0331] (2) Then it is loaded into a mixing tank with a stirring speed of 120 rpm, a mixing time of 40 minutes, and a stirring speed of 150 rpm.

[0332] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0333] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0334] (5) Same as step (5) in Example 1;

[0335] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 3.8 μm by an air jet mill under a nitrogen atmosphere.

[0336] (7) Same as step (7) in Example 2;

[0337] (8) Same as step (8) in Example 3; (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the RFeB magnetic powder after impurity removal.

[0338] (10) is the same as step (10) in Example 6;

[0339] (11) is the same as step (11) in Example 1.

[0340] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0341] Example 21

[0342] (1) Same as step (1) in Example 17;

[0343] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 40 minutes, and a stirring speed of 150 rpm.

[0344] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0345] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0346] (5) Same as step (5) in Example 1;

[0347] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 120 μm. Then it is ground into RFeB powder with an average particle size of 4.1 μm by an air jet mill under a nitrogen atmosphere.

[0348] (7) Same as step (7) in Example 2;

[0349] (8) Same as step (8) in Example 3;

[0350] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 50 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0351] (10) is the same as step (10) in Example 6;

[0352] (11) is the same as step (11) in Example 1.

[0353] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0354] Example 22

[0355] (1) Same as step (1) in Example 18; (2) Then put it into a stirring mixing tank, the mixing tank speed is 100 rpm, the mixing time is 40 minutes, and the stirring speed is 150 rpm;

[0356] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0357] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0358] (5) Same as step (5) in Example 1;

[0359] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 4.1 μm by an air jet mill under a nitrogen atmosphere.

[0360] (7) Same as step (7) in Example 2;

[0361] (8) Same as step (8) in Example 4;

[0362] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 50 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0363] (10) is the same as step (10) in Example 6;

[0364] (11) is the same as step (11) in Example 1.

[0365] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0366] Example 23

[0367] (1) Same as step (1) in Example 19;

[0368] (2) Then put it into a mixing tank with a stirring speed of 80 rpm, a mixing time of 40 minutes, and a stirring speed of 150 rpm.

[0369] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 80 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0370] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0371] (5) Same as step (5) in Example 1;

[0372] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.5 μm by an air jet mill under a nitrogen atmosphere.

[0373] (7) Same as step (7) in Example 5;

[0374] (8) Same as step (8) in Example 4;

[0375] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 50 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0376] (10) is the same as step (10) in Example 6;

[0377] (11) is the same as step (11) in Example 1.

[0378] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0379] Example 24

[0380] (1) Same as step (1) in Example 16;

[0381] (2) Then it is loaded into a mixing tank with a stirring speed of 120 rpm and a mixing time of 50 minutes. The stirring speed is 120 rpm.

[0382] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 100℃, and a time of 40 minutes.

[0383] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0384] (5) Same as step (5) in Example 1;

[0385] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0386] (7) Same as step (7) in Example 5;

[0387] (8) Same as step (8) in Example 3;

[0388] (9) is the same as step (9) in Example 3;

[0389] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously circulates hydrogen. The rotary furnace is set to a heating rate of 5°C / minute, a heating temperature of 300°C, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01 MPa to obtain regenerated RFeB magnetic powder.

[0390] (11) is the same as step (11) in Example 1.

[0391] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0392] Example 25

[0393] (1) Same as step (1) in Example 17;

[0394] (2) Then it is loaded into a mixing tank with a stirring speed of 120 rpm and a mixing time of 50 minutes. The stirring speed is 120 rpm.

[0395] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 100℃, and a time of 50 minutes.

[0396] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0397] (5) Same as step (5) in Example 1;

[0398] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.1 μm by an air jet mill under a nitrogen atmosphere.

[0399] (7) Same as step (7) in Example 5;

[0400] (8) Same as step (8) in Example 3;

[0401] (9) is the same as step (9) in Example 3;

[0402] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously circulates hydrogen. The rotary furnace is set to a heating rate of 5°C / minute, a heating temperature of 300°C, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01 MPa to obtain regenerated RFeB magnetic powder.

[0403] (11) is the same as step (11) in Example 1.

[0404] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0405] Example 26

[0406] (1) Same as step (1) in Example 18;

[0407] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 40 minutes, and a stirring speed of 100 rpm;

[0408] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0409] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0410] (5) Same as step (5) in Example 1;

[0411] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.5 μm by an air jet mill under a nitrogen atmosphere.

[0412] (7) Same as step (7) in Example 5;

[0413] (8) Same as step (8) in Example 9;

[0414] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0415] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously supplies hydrogen. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 300℃, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0416] (11) is the same as step (11) in Example 1.

[0417] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0418] Example 27

[0419] (1) Same as step (1) in Example 19;

[0420] (2) Then put it into a mixing tank with a stirring speed of 80 rpm, a mixing time of 40 minutes, and a stirring speed of 100 rpm;

[0421] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0422] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃ and held for 60 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 980℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0423] (5) Same as step (5) in Example 1;

[0424] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.5 μm by an air jet mill under a nitrogen atmosphere.

[0425] (7) Same as step (7) in Example 12;

[0426] (8) Same as step (8) in Example 9;

[0427] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0428] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously supplies hydrogen. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 300℃, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0429] (11) is the same as step (11) in Example 1.

[0430] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0431] Example 28

[0432] (1) Same as step (1) in Example 16;

[0433] (2) Then put it into a mixing tank with a stirring speed of 100 rpm, a mixing time of 50 minutes, and a stirring speed of 120 rpm.

[0434] (3) After mixing, the powder is loaded into the rotary furnace in batches. The rotation speed is 120 rpm, the heating temperature is 100℃, and the time is 60 minutes.

[0435] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0436] (5) Same as step (5) in Example 1;

[0437] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0438] (7) Same as step (7) in Example 12;

[0439] (8) Same as step (8) in Example 9;

[0440] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 30 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0441] (10) is the same as step (10) in Example 11;

[0442] (11) is the same as step (11) in Example 1.

[0443] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0444] Example 29

[0445] (1) Same as step (1) in Example 18;

[0446] (2) Then put it into a mixing tank with a stirring speed of 80 rpm, a mixing time of 30 minutes, and a stirring speed of 100 rpm;

[0447] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0448] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0449] (5) Same as step (5) in Example 1;

[0450] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 150 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0451] (7) Same as step (7) in Example 12;

[0452] (8) Same as step (8) in Example 3;

[0453] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 3 times; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0454] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously supplies hydrogen. The rotary furnace is set to a heating rate of 5℃ / minute, a heating temperature of 280℃, and a holding time of 30 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01MPa to obtain regenerated RFeB magnetic powder.

[0455] (11) is the same as step (11) in Example 1.

[0456] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0457] Example 30

[0458] (1) Same as step (1) in Example 16;

[0459] (2) Then put it into a mixing tank with a stirring speed of 80 rpm, a mixing time of 30 minutes, and a stirring speed of 100 rpm;

[0460] (3) After mixing, the powder is loaded into the rotary furnace in batches, with a rotation speed of 100 rpm, a heating temperature of 80℃, and a time of 60 minutes;

[0461] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 850℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 950℃ and held for 480 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.05MPa.

[0462] (5) Same as step (5) in Example 1;

[0463] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 100 μm. Then it is ground into RFeB powder with an average particle size of 3.2 μm by an air jet mill under a nitrogen atmosphere.

[0464] (7) Same as step (7) in Example 12;

[0465] (8) Same as step (8) in Example 9;

[0466] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 40 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process twice; wash again with anhydrous ethanol to obtain the purified RFeB magnetic powder.

[0467] (10) The purified RFeB magnetic powder is put back into a rotary furnace that continuously circulates hydrogen. The rotary furnace is set to a heating rate of 5°C / minute, a heating temperature of 280°C, and a holding time of 60 minutes for degassing, activation, and drying. The pressure of the upper pressure valve of the rotary furnace is set to 0.01 MPa to obtain regenerated RFeB magnetic powder.

[0468] (11) is the same as step (11) in Example 1. The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this example are shown in Table 1.

[0469] Example 31

[0470] (1) Weigh the purified RFeB type sludge and mix it with the reducing medium calcium hydride at a mass ratio of 22:1;

[0471] (2-11) are the same as steps (2-11) in Example 1.

[0472] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0473] Example 32

[0474] (1) Weigh the purified RFeB type sludge and mix it with calcium particles of the reducing medium at a mass ratio of 4:1.

[0475] (2-11) are the same as steps (2-11) in Example 19.

[0476] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0477] Example 33

[0478] (1-2) Same as steps (1-2) in Example 1. (3) After mixing, load the powder into the rotary furnace in batches, turn on the secondary vacuum pump system, and when the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.02MPa.

[0479] (4-10) are the same as steps (5-11) in Example 1.

[0480] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0481] Example 34

[0482] (1-3) are the same as steps (1-3) in Example 1.

[0483] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2 At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 780℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 900℃, held for 300 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.02MPa.

[0484] (5-11) The steps (5-11) in Example 1 are the same.

[0485] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0486] Example 35

[0487] (1-3) are the same as steps (1-3) in Example 1.

[0488] (4) While heating, turn on the secondary vacuum pump system. When the pressure gauge shows 10... -2At Pa, the rotary furnace heating rate is set to 10℃ / min, the temperature is raised to the second temperature of 820℃, and held for 30 minutes for primary reduction treatment; then the temperature is raised to the third temperature of 1020℃ and held for 120 minutes for secondary diffusion treatment of the mixed powder, and the pressure of the upper pressure valve of the rotary furnace body is controlled at 0.02MPa.

[0489] (5-11) The steps (5-11) in Example 1 are the same.

[0490] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0491] Example 36

[0492] (1-5) The steps (1-5) in Example 1 are the same.

[0493] (6) The alloy ingot is loaded into a crusher and crushed to an average particle size of 200 μm. Then it is ground into RFeB powder with an average particle size of 10 μm by an air jet mill under a nitrogen atmosphere.

[0494] (7-11) The steps (7-11) in Example 1 are the same.

[0495] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0496] Example 37

[0497] (1-6) The steps (1-6) in Example 1 are the same.

[0498] (7) Mix acetic acid, deionized water and anhydrous ethanol in a volume ratio of 5:10:100 to prepare a cleaning solution for removing impurities;

[0499] (8-11) are the same as steps (8-11) in Example 1.

[0500] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0501] Example 38

[0502] (1-8) The steps (1-8) in Example 1 are the same.

[0503] (9) Place the cleaner into the ultrasonic generator, set the ultrasonic frequency to 100Hz, clean for 20 seconds, let the mixture stand for about 1 minute after cleaning, pour out the solution at the top of the cleaner and add the cleaning solution again, repeat the above cleaning process 6 times; wash again with anhydrous ethanol to obtain the impurity-removed RFeB magnetic powder.

[0504] The total rare earth element content, saturation magnetization, and coercivity test results of the air-jet milled RFeB powder and the regenerated RFeB magnetic powder in this embodiment are shown in Table 1.

[0505] Table 1. Test results of total rare earth elements, saturation magnetization, and coercivity of RFeB powder and regenerated RFeB magnetic powder from air-jet mill.

[0506]

[0507] In summary, the method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste of the present invention uses purified RFeB-type oily sludge, combined with rotary heating, primary reduction treatment, secondary diffusion treatment, and cleaning of the RFeB powder from the air jet mill using a cleaning solution, which effectively improves the magnetic properties of the regenerated RFeB magnetic powder.

[0508] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0509] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0510] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste, characterized in that, R is one or more rare earth elements; The method includes: mixing purified RFeB sludge with a reducing medium at a mass ratio of (1~30):1, placing it in a vacuum rotary furnace with an inert gas, rotating and heating it at a first temperature of 70~150℃ for 1~300 minutes, adjusting the vacuum degree, performing a first-stage reduction treatment at a second temperature of 600~890℃ for 1~300 minutes, and performing a second-stage diffusion treatment at a third temperature of 900~1100℃ for 300~480 minutes to obtain an alloy ingot, which is then powdered to obtain regenerated RFeB magnetic powder; The reducing medium includes one or more of calcium hydride, calcium granules, calcium chloride, and sodium borohydride; The pressure of the upper pressure valve of the vacuum rotary furnace is 0.001~1MPa; The purification includes primary purification and secondary purification; The first purification step includes: raising the temperature of the vacuum rotary furnace and introducing inert gas into the vacuum rotary furnace until the temperature of the vacuum rotary furnace stabilizes at 100~300℃; and continuously introducing inert gas for 30~120 minutes. The secondary purification includes: evacuating the vacuum rotary furnace until the vacuum level inside the vacuum rotary furnace reaches a set threshold, and setting the pressure of the pressure limiting valve of the vacuum rotary furnace to 1~2 atm; raising the temperature of the vacuum rotary furnace and introducing purified gas into the vacuum rotary furnace until the temperature of the vacuum rotary furnace stabilizes at 300~500℃; continuously introducing purified gas for 60~120min; the purified gas is a mixture of hydrogen and inert gas, wherein the volume ratio of hydrogen to inert gas is 20:80~50:50, and the flow rate of the purified gas is 30~70mL / min.

2. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, When the reducing medium is calcium hydride, the mass ratio of purified RFeB-type sludge to the reducing medium is (11~19):

1.

3. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, When the reducing medium is calcium particles, the mass ratio of the purified RFeB-type sludge to the reducing medium is (6~9):

1.

4. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, The rotary heating includes: rotary heating at a first temperature of 80~100℃ for 1~300 minutes.

5. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, The primary reduction process includes: maintaining a temperature of 700-890℃ for 1-300 minutes.

6. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, The secondary diffusion process includes: maintaining a temperature of 1020~1040℃ for 300~480 minutes.

7. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 1, characterized in that, The powder preparation includes: crushing alloy ingots and producing RFeB powder by air jet milling; mixing and cleaning the RFeB powder with a cleaning solution to obtain impurity-removed RFeB magnetic powder; and degassing, activating and drying the RFeB magnetic powder to obtain regenerated RFeB magnetic powder.

8. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 7, characterized in that, The impurity removal cleaning solution contains 0.1~10wt% acetic acid.

9. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 7, characterized in that, The impurity removal cleaning solution comprises acetic acid, water, and anhydrous ethanol in a volume ratio of (1~5):(8~20):

100.

10. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 7, characterized in that, The mass ratio of the RFeB powder to the impurity removal and cleaning liquid in the air jet mill is 1:(10~200).

11. The method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste according to claim 7, characterized in that, The degassing, activation, and drying process includes: loading the purified RFeB magnetic powder into a rotary furnace through which hydrogen is continuously introduced; setting the rotary furnace heating rate to 1~10℃ / min; setting the heating temperature to 180~400℃; and holding the temperature for 10~600 minutes.

12. A regenerated RFeB magnetic powder, characterized in that, It is prepared by the method for efficiently producing regenerated RFeB magnetic powder from RFeB-type oily sludge waste as described in any one of claims 1 to 11.

13. The regenerated RFeB magnetic powder according to claim 12, characterized in that, Compared with purified RFeB sludge, the total rare earth element retention rate of regenerated RFeB magnetic powder is ≥82%.

14. A regenerated RFeB magnet, characterized in that, The regenerated RFeB magnet comprises 0.1 to 100 wt% of regenerated RFeB magnetic powder prepared by the method for efficiently preparing regenerated RFeB magnetic powder from RFeB-type oily sludge waste as described in any one of claims 1 to 11, or regenerated RFeB magnetic powder as described in any one of claims 12 to 13.

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