Efficient purification method for rfeb oil sludge and use

Abstract

The present application discloses an efficient purification method for RFeB oil sludge and the use, wherein R is one or more of rare earth elements. The method comprises the following steps: placing pretreated RFeB oil sludge into a vacuum atmosphere rotary kiln into which an inert gas is introduced, and performing primary purification at 100-300ºC; and when the vacuum degree of the vacuum atmosphere rotary kiln reaches a set threshold value, introducing a purification gas into the vacuum atmosphere rotary kiln, and performing secondary purification on the RFeB oil sludge that has undergone primary purification at 300-500ºC. By means of the technical solution of the present disclosure, the oil removal rate of RFeB oil sludge reaches 95% or higher (the content of C and H in the oil sludge), the oxygen content of the sludge is reduced by about 60-80%, and the loss of rare earth R, etc., is virtually avoided during the process of treatment.

Description

A high-efficiency purification method for RFeB oily sludge waste and its application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed with the Patent Office of China on March 4, 2024, with application number 2024102399240, entitled “A High-Efficiency Purification Method and Application of RFeB-Type Oil Sludge Waste,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of rare earth permanent magnet oil sludge waste reprocessing, and in particular to a high-efficiency purification method and application of RFeB oil sludge waste. Background Art

[0004] Rare earth permanent magnets (RFeB, where R represents a rare earth element) possess extremely high magnetic properties and excellent magnetic permeability, coercivity, and remanence. They are widely used in industries such as computers, automobiles, instruments, meters, household appliances, petrochemicals, healthcare, and aerospace. The production and processing of rare earth permanent magnets generates a significant amount of waste, such as cutting waste, grinding waste, sintering waste, and oil sludge waste. Oil sludge waste, primarily composed of lubricants and coolants used in the cutting and grinding processes, and cleaning agents used in the cleaning process, combined with other waste materials, accounts for 35% to 50% of the total waste, resulting in a significant waste of rare earth resources. Furthermore, the long-term accumulation of oil sludge waste poses a serious environmental pollution risk.

[0005] Currently, the most common industrial treatment method for RFeB oil sludge waste involves wet or pyrometallurgical processes, adding large amounts of chemical reagents, followed by high-temperature calcination, and ultimately purification to produce rare earth oxides. This technology is characterized by lengthy processing steps, high costs, high energy consumption, and significant pollution, resulting in low added value for the recovered rare earth oxides. Furthermore, rare earth separation produces approximately 70% solid waste residue of metal oxides such as Fe, Co, Al, and Cu, resulting in significant resource waste. Other treatment methods involve hydrogen pressure crushing, pulverization, and subsequent sintering to produce magnets, but these methods suffer from lengthy processing cycles and high energy consumption.

[0006] Currently, there are treatment methods involving crushing, oxidation roasting, acid leaching, and the extraction of rare earth metals. These solutions utilize acidic reagents such as hydrochloric acid, nitric acid, acetic acid, and oxalic acid during the treatment process. Even weak acids can lead to the loss of rare earth metals and iron. Other treatment methods involve repeatedly washing RFeB oily sludge waste with strong acids, strong bases, degreasing emulsifiers, and chlorides to remove oil and impurities. The use of alkaline reagents such as sodium hydroxide, potassium hydroxide, alkaline inorganic salts, ammonium salts, and degreasing agents also results in the loss of rare earth metals. Furthermore, the degreasing emulsifiers and their higher derivatives used in these treatments often dissolve rare earth and metal oxides, introducing excessive carbon impurities with the wastewater. The use of chlorides during these treatments makes the chloride ions difficult to remove from the sludge and subsequently present in the regenerated rare earth magnets produced later. When the magnets are exposed to moisture or operate in a warm or humid environment, the rare earth permanent magnet material can rapidly self-corrode, posing unexpected risks to the magnets themselves and the devices in which they are used.

[0007] Summary of the Invention

[0008] The embodiments of the present application provide a highly efficient purification method and application of RFeB type oily sludge waste to at least solve the above technical problems existing in the prior art.

[0009] In a first aspect, the present invention provides an efficient purification method for RFeB oil sludge waste, where R is one or more rare earth elements; the method comprises the following steps:

[0010] The pre-treated RFeB oil sludge waste is placed in a vacuum gas rotary kiln with inert gas and purified at 100-300°C;

[0011] When the vacuum degree of the vacuum gas rotary kiln reaches a set threshold, purified gas is introduced into the vacuum gas rotary kiln to perform secondary purification on the RFeB type oily sludge waste material after the primary purification at 300-500°C.

[0012] Further, the primary purification includes:

[0013] Raise the temperature of the vacuum gas rotary furnace and introduce inert gas into the vacuum gas rotary furnace until the temperature of the vacuum gas rotary furnace is stabilized at 100-300°C;

[0014] The inert gas is continuously introduced for 30 to 120 minutes to purify the pretreated RFeB type oily sludge waste.

[0015] Furthermore, the flow rate of the inert gas is 70-110 mL / min.

[0016] Furthermore, the secondary purification includes:

[0017] The vacuum gas rotary furnace is evacuated until the vacuum degree in the vacuum gas rotary furnace reaches a set threshold value, and the pressure of the pressure limiting valve of the vacuum gas furnace is set to 1-2 atm;

[0018] Raise the temperature of the vacuum gas rotary furnace and introduce purified gas into the vacuum gas rotary furnace until the temperature of the vacuum gas rotary furnace stabilizes at 300-500°C;

[0019] The purified gas is continuously introduced for 60 to 120 minutes to allow the RFeB type oily sludge waste to undergo secondary purification after the primary purification.

[0020] Furthermore, the purified gas is a mixed gas of hydrogen and inert gas, wherein the volume ratio of hydrogen to inert gas is 20:80 to 50:50.

[0021] Furthermore, the flow rate of the purified gas is 30 to 70 mL / min.

[0022] Furthermore, the RFeB oily sludge waste material is pretreated by at least one of drying, activation, and pre-purification methods.

[0023] Further, the activation comprises:

[0024] The dried RFeB type oily sludge waste material and the diluent are added into the oily sludge material mixing and filtering device and stirred, so that the dried RFeB type oily sludge waste material and the diluent are fully contacted to realize activation.

[0025] Furthermore, the diluent includes at least two of 60% to 95% of alcohol compounds, 5% to 80% of ketone or ester compounds, 5% to 10% of petroleum derivatives, and 5% to 40% of weak alkaline solution, calculated by volume percentage.

[0026] Furthermore, the alcohol compound is a lower alcohol compound having no more than three carbon atoms.

[0027] Furthermore, the petroleum derivative includes at least one of gasoline and petroleum ether.

[0028] Furthermore, based on the mass of the dried RFeB oily sludge waste, the amount of diluent added is 1 to 3 L / kg.

[0029] Furthermore, the stirring rate is 30 to 100 r / min, and the stirring time is 30 to 120 min.

[0030] Further, the pre-purification includes:

[0031] The activated RFeB oil sludge waste is centrifuged and baked to achieve pre-purification.

[0032] Furthermore, the baking temperature is 40-50° C., and the baking time is 1-5 hours.

[0033] Furthermore, the RFeB type oily sludge waste is further baked at 40-50° C. for 30-90 minutes under stirring.

[0034] Furthermore, the centrifugal conditions are a centrifugal rate of 150 to 380 r / min and a centrifugal time of 1 to 10 min.

[0035] Furthermore, the oil sludge mixed material filtering device includes:

[0036] Chassis;

[0037] A mixing barrel is provided in the chassis, and a discharge channel communicating with the interior is provided below the mixing barrel;

[0038] A mixing basket, used for holding RFeB oily sludge waste, the mixing basket being detachably connected to the chassis;

[0039] an agitator, disposed in the mixing barrel, for agitating the RFeB oily sludge waste in the mixing barrel;

[0040] A drive motor is provided on the chassis above the mixing barrel, and the drive motor is connected to the stirrer to drive the stirrer to rotate;

[0041] The vibration motor is arranged below the mixing barrel and is used to make the RFeB type oily sludge waste in the mixing barrel flow out from the discharge channel.

[0042] Furthermore, the oil sludge material mixing filtering device further includes:

[0043] A spring, one end of which is connected to the bottom of the mixing barrel, and the other end of which is connected to a base, wherein the base is used to place the mixing barrel.

[0044] Furthermore, the oil sludge mixed material filtering device further includes a lifting component, and the lifting component is used to control the lifting of the base;

[0045] The lifting assembly includes a traction rope, a pulley, a rotating shaft and a motor; the motor is fixed on the chassis, and the output shaft of the motor is connected to the rotating shaft for driving the rotating shaft to rotate; two pulleys are provided, and the two pulleys are respectively rotatably connected to the chassis; the traction rope is wrapped around the rotating shaft and one end of it is fixed to the rotating shaft, and the other end of the traction rope passes around the pulley and is fixed to the base.

[0046] Furthermore, the agitator includes a stirring shaft, a stirring disk and stirring teeth, the stirring disk is fixed at the lower end of the agitator, and the stirring teeth are fixed on the circumference of the stirring disk; the axial direction of the stirring shaft is parallel to the axial direction of the mixing barrel, and the upper end of the stirring shaft is connected to the drive motor.

[0047] Furthermore, the vacuum atmosphere rotary kiln comprises:

[0048] Box;

[0049] The furnace body is transversely arranged in the box body; the furnace body has an internal hollow cavity for placing RFeB type oily sludge waste;

[0050] an air inlet chamber, connected to one end of the furnace body and having an axis of the air inlet chamber coincident with an axis of the furnace body;

[0051] an exhaust chamber, connected to the other end of the furnace body and having an axis of the exhaust chamber coincident with an axis of the furnace body;

[0052] A driving device, disposed in the box, for driving the furnace body to rotate;

[0053] A pressure relief device and a vacuum gauge are provided above the furnace body. The pressure relief device is connected to the inside of the furnace body and is used to control the pressure inside the furnace body; the vacuum gauge is used to monitor the vacuum degree inside the furnace body.

[0054] Furthermore, a material lifting plate is provided in the furnace body. The material lifting plate is a spiral structure and the axis of the material lifting plate coincides with the axis of the furnace body. Both ends of the material lifting plate are respectively fixed to the inner walls of both ends of the furnace body.

[0055] Furthermore, a lifting cylinder is provided on the side wall of the box body, and the piston rod of the lifting cylinder is connected to one end of the air inlet chamber or the exhaust chamber, which is used to drive the furnace body to tilt so as to pour out the purified RFeB oil sludge waste in the furnace body.

[0056] In a second aspect, an embodiment of the present application provides an RFeB oil sludge powder, which is prepared according to the above-mentioned efficient purification method for RFeB oil sludge waste.

[0057] In a third aspect, an embodiment of the present application provides an application of RFeB type oil sludge powder in an RFeB type regenerative magnet.

[0058] The following beneficial effects can be achieved by treating RFeB type severely oxidized oil sludge waste through the technical solution of this application:

[0059] The pre-treatment of RFeB type oily sludge waste has the following effects: (1) it can activate the organic molecules such as machining oil, cutting fluid, etc. and separate them from the surface of the magnetic powder particles, and the purification effect is better; (2) the purification process makes the oily sludge components more uniform, which is helpful for the stability control of subsequent processes; (3) the technical solution of the present application does not involve multiple cleaning of the oily sludge waste, will not cause the loss of rare earth elements, Fe and other elements, will not generate cleaning waste liquid, and will not increase additional costs; (4) the technical solution of the present application does not require the use of a large amount of chemical reagents, will not introduce additional impurities and environmental pollution; (5) Filtration and impurity removal can remove solid impurities mixed into the oily sludge during the machining process.

[0060] The first purification process is mainly to carry out two-stage low-temperature volatilization treatment on the pretreated oil sludge slurry: (1) The first stage is a low-temperature and long-term baking (furnace temperature 40-60°C, baking time 1-5 hours) as a pre-purification process, the purpose of which is to remove the diluent in the oil sludge slurry and the organic macromolecules that are activated and separated from the surface of magnetic particles, rare earth and metal oxides; (2) The second stage is temperature (furnace temperature 100-300°C) with auxiliary lifting plate stirring to further remove the diluent, C, H, O organic molecules in the oil sludge and some O on the surface of magnetic particles, rare earth and metal oxides; (3) The exhaust chambers of the furnaces in both stages are open, which is more conducive to the volatilization and purification process; (4) The inert gas is introduced to prevent the purified magnetic particles from being oxidized again, and at the same time, the volatilized impurities are quickly discharged from the furnace.

[0061] Second purification treatment: After the first purification treatment of the sludge, the furnace body is first vacuumed to remove the impurity gases and O in the furnace body. (1) The furnace body temperature is 300-500℃, and a mixture of hydrogen and inert gas is introduced to completely remove C, H, and O in the sludge in the form of compounds; (2) This process can also remove some O on the surface of magnetic powder particles, rare earth and metal oxides; (3) The furnace body pressure limit valve is set in this process to achieve the purification process under constant temperature and pressure conditions, maintain the stability of the furnace atmosphere and the pressure changes during the reaction process.

[0062] Through the technical solution of the present application, the oil removal rate of RFeB type oily sludge waste can reach more than 95% (C and H content in the oily sludge), the oxygen content of the sludge is reduced by about 60-80%, and there is almost no loss of rare earth R and the like during the treatment process. It is a key technical process for the subsequent preparation of regenerated RFeB type magnetic powder and regenerated RFeB type magnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] FIG1 shows a schematic flow chart of an efficient purification method for RFeB oily sludge waste according to an embodiment of the present application;

[0065] FIG2 shows a schematic structural diagram of an oil sludge mixed material filtering device according to an embodiment of the present application;

[0066] FIG3 shows a schematic structural diagram of a mixing barrel and a base according to an embodiment of the present application;

[0067] FIG4 shows a schematic structural diagram of a mixing basket according to an embodiment of the present application;

[0068] FIG5 shows a schematic structural diagram of an agitator according to an embodiment of the present application;

[0069] FIG6 shows a schematic structural diagram of a vacuum atmosphere rotary kiln for oil sludge purification according to an embodiment of the present application;

[0070] FIG7 shows a schematic structural diagram of a vacuum atmosphere rotary kiln in an open state for purifying oil sludge according to an embodiment of the present application;

[0071] FIG8 shows a schematic cross-sectional structure diagram of a furnace body according to an embodiment of the present application;

[0072] FIG9 is a schematic structural diagram of a vacuum atmosphere rotary kiln in an inclined state for oil sludge purification according to an embodiment of the present application;

[0073] FIG10 shows the appearance of NdFeB oil sludge waste according to an embodiment of the present application;

[0074] FIG11 shows the optical microscope morphology of NdFeB oil sludge waste in an embodiment of the present application;

[0075] FIG12 shows the appearance of the NdFeB oil sludge waste after drying according to an embodiment of the present application;

[0076] FIG13 shows the appearance of the purified NdFeB sludge waste in an embodiment of the present application.

[0077] Explanation of the accompanying drawings: The accompanying drawings of the oil sludge mixing and filtering device shown in Figures 1 to 4 are as follows: 1. Chassis; 11. Door panel; 12. Base; 121. Guide rod; 13. Limiting enclosure; 14. Disc; 141. Block; 15. Guide groove; 2. Mixing barrel; 21. Discharge channel; 22. Insert plate; 23. Engaging part; 3. Mixing basket; 31. Buckle; 4. Agitator; 41. Agitating shaft; 42. Agitating disk; 421. Through hole; 43. Agitating teeth; 5. Driving motor; 6. Vibrating motor; 7. Spring; 71. Telescopic column; 8. Lifting assembly; 81. Traction rope; 82. Pulley; 83. Rotating shaft; 84. Lifting motor; 9. Control assembly.

[0078] The reference numerals of a vacuum atmosphere rotary furnace for sludge purification shown in Figures 6 to 9 are as follows: 1. box body; 11. upper box body; 12. middle box body; 13. lower box body; 131. support member; 2. furnace body; 21. lifting plate; 3. air inlet chamber; 31. gas flow meter; 4. exhaust chamber; 41. exhaust valve; 5. driving device; 51. motor; 52. gear; 53. gear ring; 6. pressure relief device; 7. vacuum gauge; 8. lifting cylinder; 9. starting component; 10. control component. DETAILED DESCRIPTION

[0079] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0080] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0081] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0082] Rare earth permanent magnet machining processes such as wire cutting, grinding, drilling, chamfering before electroplating, and slicing are prone to produce heavily oxidized RFeB type sludge waste. The characteristic of RFeB type heavily oxidized sludge waste is that it contains a large amount of oxide components. Compared with other types of waste, its oxide content is higher, where R refers to rare earth elements praseodymium (Pr), europium (Eu), neodymium (Nd), etc. This waste material forms an oily sludge shape with high viscosity and is difficult to remove by conventional physical treatment methods. At present, a large amount of chemical reagents are used to treat this type of heavily oxidized sludge waste, which not only has defects such as long processing flow, high cost, high energy consumption, high pollution, and introduction of new impurities, but also leads to a significant reduction in the content of rare earth elements. Based on this, the present application provides an efficient purification method for RFeB type sludge waste.

[0083] FIG1 shows a schematic flow chart of a method for efficiently purifying RFeB oily sludge waste provided in one embodiment of the present application. The method comprises the following steps:

[0084] S1. The pretreated RFeB oil sludge waste is placed in a vacuum gas rotary kiln with an inert gas flow and purified at 100-300°C.

[0085] The main components of RFeB type oily sludge waste are rare earth R and iron oxide. The oily sludge waste contains a large amount of machining oil, cutting fluid and grinding fluid. The purpose of purifying RFeB type oily sludge waste is to remove oil and impurities in RFeB type oily sludge waste.

[0086] In a preferred implementation, the pretreated RFeB oil sludge waste is obtained by one or more treatment methods including drying, activation, and pre-purification.

[0087] Because RFeB waste sludge is typically a thin, paste-like material, drying is necessary to ensure the measured effective mass (the net mass of the sludge after the liquid evaporates) is controllable. Specifically, the sludge is placed on a stainless steel mesh tray (e.g., 40 cm x 40 cm), spread flat, and then dried in a circulating air oven. Drying removes moisture and minor oil contaminants. To ensure thorough drying, the thickness of the spread sludge should generally not exceed 5 cm. The oven temperature should be set at 100 ± 2°C for 2 hours.

[0088] The dried RFeB oily sludge waste is then activated. The activation steps include:

[0089] The dried RFeB oil sludge waste material and a diluent are added to an oil sludge mixing and filtering device and stirred to ensure full contact between the dried RFeB oil sludge waste material and the diluent for activation. The diluent comprises, by volume, at least two of the following: 60% to 95% alcohol compounds, 5% to 80% ketone or ester compounds, 5% to 10% petroleum derivatives, and 5% to 40% weak alkaline solution. The alcohol compound, ketone, or ester compound serves as the diluent solvent, with the alcohol compound preferably being a lower alcohol, such as ethanol, ethylene glycol, or isopropanol. Ketone or ester compounds include butanone and ethyl acetate, and petroleum derivatives include at least one of gasoline and petroleum ether. The weak alkaline solution can be low-concentration ammonia water, such as a 1% ammonia solution by mass. The above diluent components are for illustrative purposes only.

[0090] By fully contacting the dried RFeB oil sludge waste with the diluent, the diluent has the following functions:

[0091] (1) RFeB oil sludge waste directly purchased by the recycling plant generally has a high concentration. Adding diluent can dilute it to an appropriate concentration, which helps to improve the efficiency of subsequent purification treatment and operational safety.

[0092] (2) RFeB type oily sludge waste has high viscosity. The addition of diluent can reduce its viscosity, making the oily sludge waste easier to transport, stir and process.

[0093] (3) The diluent helps to disperse the solid particles in the RFeB oil sludge waste and reduce the aggregation phenomenon in the waste, making the waste easier to handle in the subsequent solid-liquid separation process (such as filtration or centrifugation).

[0094] The sludge dilution and activation process is performed in the sludge mixing and filtration unit. Specifically, the dried sludge is weighed and poured into a mixing basket. A prepared diluent is then added to the mixing barrel to ensure full contact and activation of the sludge particles in a liquid state. 1 to 3 liters of diluent are added per kilogram of sludge. Too little diluent increases the viscosity of the sludge slurry, preventing the sludge particles from fully contacting and activating with the diluent. Impurities mixed in the sludge are difficult to filter, resulting in poor oil removal during the pre-purification process. Too much diluent prolongs the sludge pre-drying time, leading to further oxidation and the introduction of impurities such as carbon, which compromises oil removal and increases equipment energy consumption. Then set the stirring rate of the agitator in the mixing barrel. In order to make the oil sludge and diluent fully contact, activate, and have uniform composition, and avoid stirring too fast and splashing the slurry, set the stirring rate to 30-100 rpm and the stirring time to 30-120 minutes. After homogenization, the oil sludge slurry is measured by Tu 4 viscosity cup, and its viscosity is 80-120 seconds.

[0095] In order to avoid the loss caused by the slurry remaining in the agitator and mixing basket, and to remove the impurities mixed in the sludge (non-magnetic impurities mixed in during the magnet machine processing), after the slurry is stirred evenly, turn off the stirring, raise the agitator together with the mixing basket or lower the mixing barrel downward, so that the mixing basket is about 10 cm away from the slurry liquid level in the mixing barrel, set the centrifugal speed to 150-380 rpm, and the centrifugal time to 1-10 minutes. Shake off the slurry remaining on the mixing basket, and the filter residue at the bottom of the mixing basket is the impurities in the RFeB type sludge waste, which can be removed.

[0096] After activation, the RFeB oily sludge waste is pre-purified by baking. The sludge in the mixing barrel is rinsed clean, and the rinse liquid is poured into the furnace. (Regarding the treatment of the clear liquid, the types of machining oil, cutting fluid, and grinding fluids vary greatly depending on the source of the sludge. Therefore, the clear liquid can be analyzed for its composition. If the rare earth and Fe content is less than 0.05%, the clear liquid does not need to be poured into the furnace. This reduces baking time and energy consumption, and the clear liquid can be recycled and reused as a diluent.) The volume of the sludge and clear liquid should be less than half the furnace volume. Close the furnace door, open the upper exhaust port, set the furnace temperature to 40-60°C, and bake for 1-5 hours. Then, rotate the furnace at 5-15 rpm, and continue baking for 30-90 minutes while the lifting plate stirs the furnace, completing the pre-purification process. This process removes the diluent from the sludge slurry as well as the organic macromolecules that have been removed from the surface of the magnetic particles, rare earth elements, and metal oxides after activation.

[0097] The furnace temperature is then raised to 100-300°C, while an inert gas, such as argon or nitrogen, is introduced at a flow rate of 70-110 ml / min. Once the temperature stabilizes, the inert gas is continued for 30-120 minutes to achieve the first purification step. This process further removes diluents, organic C, H, and O molecules from the sludge, and some O on the surfaces of magnetic particles, rare earth elements, and metal oxides.

[0098] S2. When the vacuum degree of the vacuum gas rotary kiln reaches a set threshold, purified gas is introduced into the vacuum gas rotary kiln to perform secondary purification on the RFeB type oily sludge waste material after the primary purification at 300-500°C.

[0099] Turn off the inert gas, close the exhaust port on the exhaust chamber door, turn on the mechanical pump and diffusion pump to start vacuuming the furnace body. When the vacuum reaches 10 -4When the temperature reaches 1000 Pa, turn off the mechanical pump and diffusion pump, open the furnace's upper pressure valve, set the pressure to 1-2 atm, and slowly introduce a purified gas, a hydrogen-argon mixture with a hydrogen-to-argon volume ratio of 20:80-50:50, at a flow rate of 30-70 ml / min. Simultaneously, raise the furnace temperature to 300-500°C. Once the temperature stabilizes, continue introducing the hydrogen-argon mixture, maintaining a constant temperature and pressure within the furnace, for 60-120 minutes. It should be noted that hydrogen alone can also be used as the purified gas.

[0100] After the secondary purification treatment is completed, turn off the furnace heating, gas and pressure limiting valve. When the temperature in the furnace is lower than 30±5℃, inert gas protection is introduced again, the furnace tilt switch is turned on, and the treated sludge powder is poured into a sealed stainless steel material tank. The degreasing and impurity removal pretreatment process of RFeB type sludge waste is completed.

[0101] Through the technical solution of the present application, the oil removal rate of RFeB type oily sludge waste can reach more than 95% (C and H content in the oily sludge), the oxygen content of the sludge is reduced by about 60-80%, and there is almost no loss of rare earth R and the like during the treatment process. It is a key technical process for the subsequent preparation of regenerated RFeB type magnetic powder and regenerated RFeB type magnets.

[0102] In one example, the present application also provides an RFeB type oil sludge powder prepared according to the above purification method.

[0103] In one example, the present application also provides an application of RFeB type oil sludge powder in RFeB type regenerated magnets. According to the required composition and performance requirements of the regenerated magnet, the purified RFeB type oil sludge powder is mixed with other components (such as iron powder, boron powder) in an appropriate ratio to ensure that the obtained regenerated magnet has the required magnetic properties and microstructure. The mixture is pressed into a magnet blank of the desired shape, which can be formed by cold isostatic pressing, injection molding or extrusion. The magnet blank is sintered by heat treatment to form a dense structure at high temperature. During the sintering process, the material particles combine to form the final structure of the magnet, and it has good magnetic properties. Finally, according to specific needs, the sintered magnet is subjected to necessary machining, grinding, trimming and other operations to achieve the required size and surface quality.

[0104] In a preferred implementation, since the purification process of this application uses two devices, namely, an oil sludge material mixing and filtering device and a vacuum atmosphere rotary furnace for oil sludge material purification, the devices are described in detail below with reference to the accompanying drawings.

[0105] 2 to 6 show a schematic structural diagram of an oil sludge mixing and filtering device provided in one embodiment of the present application. The device includes: a chassis 1, a mixing barrel 2, a mixing basket 3, an agitator 4, a drive motor 5, and a vibration motor 6.

[0106] As shown in Figure 2, the chassis 1 is a hollow rectangular parallelepiped. The interior space of the chassis 1 is used to accommodate structural components such as the mixing barrel 2 and mixing basket 3. Other locations in the chassis 1 also facilitate the installation of other components of the device. A door panel 11 is also provided on one side of the chassis 1. This door panel 11 is connected to the side wall of the chassis 1 via a hinge. This door panel 11 can be opened, closed, or completely removed to facilitate user experiments and to facilitate the repair, installation, or replacement of hardware. Furthermore, the provision of the door panel 11 prevents dust and other debris from entering the mixing barrel 2 within the chassis 1.

[0107] In a preferred embodiment, the mixing barrel 2 is configured as a cylindrical container with an opening at the top, and may also be provided with a lid. Alternatively, the mixing barrel 2 may be designed in a funnel shape, as shown in Figures 2-3 , where the upper portion of the mixing barrel 2 is cylindrical and the lower portion is inverted conical. This configuration facilitates the natural flow of the sludge during mixing, thereby improving the mixing effect. Due to the complex composition of the sludge and the need to add chemical reagents to the mixing barrel 2, the mixing barrel 2 is preferably made of stainless steel or other corrosion-resistant materials, although this application does not impose any restrictions on this.

[0108] A discharge channel 21 is provided at the bottom or side of the mixing barrel 2 to facilitate the discharge of the mixed sludge waste. The discharge channel 21 may be an opening or a discharge port connected to a pipe. A movable plug plate 22 is installed at the discharge channel 21 to control the flow of the sludge waste. The plug plate 22 may be a gate that can be opened or closed, and the flow rate and flow of the sludge material can be controlled by adjusting the position of the plug plate 22. In addition, in order to facilitate the operation of the plug plate 22, an operating rod or handle may be installed on the plug plate 22. The position of the plug plate 22 may be easily adjusted by the operating rod or handle to open or close the discharge channel 21. In order to prevent the sludge waste from leaking during the mixing process and to ensure that the discharge channel 21 and the plug plate 22 have good sealing properties, materials such as rubber gaskets and sealants may be used to improve the sealing effect and prevent the sludge material from overflowing.

[0109] Handles are symmetrically fixed to the sidewalls at the top of the mixing barrel 2, making it easier for operators to move the mixing barrel 2 or for mechanical equipment to lift it. A locking member 23 is also fixed to the sidewalls at the top of the mixing barrel 2, securing the mixing barrel 2 and the mixing basket 3. To ensure a stable connection between the mixing barrel 2 and the mixing basket 3, multiple locking members 23 can be provided, for example, three or four evenly spaced along the circumference of the mixing barrel 3.

[0110] In a preferred embodiment, a base 12 is provided on the bottom surface of the chassis 1 for placing the mixing barrel 2. To prevent the mixing barrel 2 from detaching from the base 12, a retaining plate 13 is fixed around the base 12. The base 12 also houses a vibration motor 6, which in this example is fixed to the bottom surface of the base 12. The vibration motor 6 ensures that the oil sludge filtered into the mixing barrel 2 is thoroughly mixed with the diluent.

[0111] In a preferred embodiment, a spring 7 is provided on the bottom of the mixing barrel 2. The upper end of the spring 7 is fixed to the bottom of the mixing barrel 2, and the lower end of the spring 7 is fixed to the base 12. The main function of the spring 7 provided at the bottom of the mixing barrel 2 is to provide power for stirring and mixing the materials. Specifically, the spring 7 can play the following roles:

[0112] 1. Stirring and mixing: The elasticity of the spring 7 can generate vibration force to stir and mix the sludge in the mixing barrel 2, thereby ensuring that the materials are fully and evenly mixed together, thereby improving the mixing efficiency and quality.

[0113] 2. Prevent material from agglomerating: The vibration of the spring 7 can prevent the sludge from agglomerating and accumulating at the bottom of the barrel, keeping the sludge loose, which is crucial for handling viscous or easily agglomerated sludge.

[0114] 3. Promote fluidity: The vibration of spring 7 can improve the fluidity of sludge and reduce the adhesion of sludge.

[0115] In order to improve the effect of the spring 7, multiple springs 7 can be evenly arranged on the ground of the mixing barrel 2. In addition, in order to prevent the spring 7 from tilting during the vibration process, a telescopic column 71 is provided inside the spring 7, that is, the spring 7 is sleeved on the telescopic column 71, and the telescopic column 71 can play a guiding role, wherein the upper end of the telescopic column 71 is connected to the bottom surface of the mixing barrel 2, and the lower end of the telescopic column 71 is connected to the base 12.

[0116] The mixing basket 3 is used to hold the oil sludge material, which can be easily mixed and filtered. The mixing basket 3 can be set to a cylindrical shape, a rectangular shape, etc. The mixing basket 3 is made of stainless steel mesh or other corrosion-resistant material mesh. The mesh size can be determined according to the size of the oil sludge material. As shown in Figures 2 and 4, the mixing basket 3 is cylindrical and made of stainless steel mesh. The diameter of the stainless steel mesh is 2500 mesh.

[0117] To facilitate installation of the mixing basket 3, a horizontally positioned circular disc 14 is provided within the chassis 1. Disc 14 engages with the mixing basket 3 in a snap-fit ​​manner. For example, a latch 141 is provided on the end surface of the disc 14 proximal to the mixing basket 3, and a buckle 31 is provided at the upper end of the mixing basket 3 to engage with the latch 141. Alternatively, the buckle 31 may be provided on the disc 14, and the buckle 141 may be provided on the mixing basket 3. Alternatively, the disc 14 and mixing basket 3 may be connected in other detachable ways, which are not limited herein.

[0118] As shown in Figure 5, the structural diagram of the agitator 4 is shown. The agitator 4 includes a stirring shaft 41, a stirring disc 42 and stirring teeth 43. The axial direction of the stirring shaft 41 is parallel to the axial direction of the mixing barrel 2. The upper end of the stirring shaft 41 is inserted into the variable contraction port of the drive motor 5, and the stirring shaft 41 is fixed by tightening the screw. The stirring disc 42 is located at the end of the stirring shaft 41, and its shape and size can be designed according to specific mixing requirements. The stirring disc 42 can be flat, spiral or propulsion type, used to produce a stirring effect and promote the mixing of materials. In this example, the stirring disc 42 is flat. A through hole 421 is provided on the stirring disc 42 to reduce the resistance of the fluid in the mixing barrel to the stirring disc 42. The stirring teeth 43 are fixed to the side wall of the stirring disc 42. A plurality of stirring teeth 43 are evenly arranged around the circumference of the stirring disc 42, and the extension directions of the plurality of stirring teeth 43 are not exactly the same. For example, the extension directions of adjacent stirring teeth 43 can be set in opposite directions to increase the shearing and stirring effect of the oil sludge during the mixing process.

[0119] As shown in FIG2 , the drive motor 5 is used to drive the agitator 4 and the mixing basket 3 to rotate. In one example, a single drive motor 5 may be provided, connected to the agitator 4 and the mixing basket 3 via a disc 14, and simultaneously drives the agitator 4 and the mixing basket 3 to rotate. In another example, two drive motors 5 may be provided, one of which is connected to the agitator 4 to control the rotation of the agitator 4. The other drive motor 5 is connected to the disc 14 to control the rotation of the mixing basket 3. In this way, the agitator 4 and the mixing basket 3 can be independently controlled.

[0120] In a preferred embodiment, if the oily sludge adhering to the agitator 4 and the mixing basket 3 is to be centrifuged after mixing, it is necessary to maintain a certain height difference between the agitator 4 and the mixing basket 3 and the liquid level in the mixing barrel 2. The device is further provided with a lifting assembly 8, which is used to drive the base 12 to rise and fall. When the base 12 is lowered a certain distance, a height difference is created between the liquid level in the mixing barrel 2 and the mixing basket 3.

[0121] As shown in Figure 2, the lifting assembly 8 includes a traction rope 81, a pulley 82, a rotating shaft 83, and a lifting motor 84. The lifting motor 84 is fixed to the side wall above the chassis 1, and the rotating shaft 83 is rotatably mounted on the top surface of the chassis 1. The output shaft of the lifting motor 84 is connected to the rotating shaft 83 to drive the rotating shaft 83 to rotate. Two pulleys 82 are provided, and the two pulleys 82 are rotatably connected to the bottom surface of the top cover of the chassis 1. The traction rope 81 is wrapped around the rotating shaft 83 with one end fixed to the rotating shaft 83. The other end of the traction rope 81 passes through the pulley 82 and is fixed to the base 12.

[0122] In a preferred implementation, the lifting assembly 8 may also be a cylinder connected to the base 12 to achieve the lifting of the base 12. The lifting assembly 8 may also include a sprocket and a chain, and the sprocket and chain cooperate to drive the base 12 to rise and fall. The present application does not limit the specific structure and implementation of the lifting assembly 8, as long as it can make the base 12 rise and fall.

[0123] In a preferred embodiment, to prevent shaking during the lifting and lowering of the base 12 and to improve the lifting effect of the base 12, a guide groove 15 is provided on the inner wall of the chassis 1. The direction of the guide groove 15 is aligned with the lifting direction of the base 12. At the same time, a guide rod 121 is fixed to the base 12 and slidably engages with the guide groove 15. When the base 12 needs to be raised or lowered, the lifting motor 84 is started, and the output shaft of the lifting motor 84 drives the rotating shaft 83 to rotate. Under the pulling force of the traction rope 81, the base 12 is raised or lowered. During this process, due to the cooperation between the guide rod 121 and the guide groove 15, the base 12 can be raised and lowered smoothly without shaking.

[0124] In a preferred implementation, the device also includes a control assembly 9 arranged on the side wall of the chassis 1. As shown in Figure 1, the control assembly 9 can include buttons such as a start / stop button, a speed adjustment button, a steering option, and a duration setting. This can provide more intuitive and clear control operations for user convenience. The control assembly 9 provided can be used to control the start and shut down of the drive motor 5, the vibration motor 6, and the lifting motor 84, and can also be used to control the speed, direction of rotation, etc. of the drive motor 5. The control assembly 9 can also be used to control the vibration mode switching of the vibration motor 6, or control the speed of the vibration motor 6 to achieve required vibration intensity and frequency. The control assembly 9 can also be used to control the speed of the lifting motor 84 to achieve control of the lifting stroke.

[0125] Figures 6 to 9 show a schematic structural diagram of a vacuum atmosphere rotary furnace for oil sludge purification provided in one embodiment of the present application. The vacuum atmosphere rotary furnace includes a box body 1, a furnace body 2, an air inlet chamber 3, an exhaust chamber 4, a driving device 5, a pressure relief device 6 and a vacuum gauge 7.

[0126] The chamber 1 of a vacuum atmosphere rotary kiln is typically made of high-temperature-resistant and corrosion-resistant materials, such as stainless steel or other alloys. Furthermore, to maintain a stable internal temperature and minimize energy loss, an insulation layer is installed within the chamber 1. This insulation layer can be filled or covered with materials such as ceramic fiber or insulation board to provide excellent thermal isolation.

[0127] As shown in Figure 6, the box body 1 is an open-close structure, comprising an upper box body 11, a middle box body 12, and a lower box body 13. The upper box body 11 and the middle box body 12 are connected on one side by a hinge, and the upper box body 11 and the middle box body 12 are fixedly connected on the other side by a buckle. In order to facilitate opening the upper box body 11, a handle can be fixed on the side wall of the upper box body 11 to facilitate operation by the operator. The middle box body 12 is connected to one side of the lower box body 13 by a hinge. It should be noted that the hinge connecting the middle box body 12 and the lower box body 13 is not on the same side as the hinge connecting the upper box body 11 and the middle box body 12, that is, the opening and closing direction of the upper box body 11 is different from that of the middle box body 12. Support members 131 are fixed on all four sides of the bottom of the lower box body 13. On the one hand, the support members 131 support the vacuum atmosphere rotary kiln as a whole; on the other hand, they prevent the box body 1 from directly contacting the ground.

[0128] As shown in Figure 7, the furnace body 2 is transversely disposed within the housing 1 and is rotatably connected to the interior of the upper housing 11. The furnace body 2 has a first end and a second end, wherein the first end of the furnace body 2 is connected to the air inlet chamber 3, and the second end of the furnace body 2 is connected to the exhaust chamber 4.

[0129] In a preferred implementation, the furnace body 2, the air inlet chamber 3 and the exhaust chamber 4 are integrally formed, and the cross-sectional area of ​​the furnace body 2 is larger than the cross-sectional area of ​​the air inlet chamber 3 and the exhaust chamber 4. The total length of the furnace body 2, the air inlet chamber 3 and the exhaust chamber 4 is the length of the rotary kiln, wherein the length of the furnace body 2 accounts for at least 1 / 2 of the entire length of the rotary kiln. Since the furnace body 2 occupies half the length of the rotary kiln, the relatively large length of the furnace body 2 can provide a larger heating area and heat preservation area, which can reduce energy loss and improve the energy efficiency of the rotary kiln. In addition, the longer length of the furnace body 2 can achieve a more sufficient reaction time and contact area. The oil sludge material is processed for a longer time in the furnace body 2, and has more opportunities to fully react with the purified gas, thereby improving the purification effect of the oil sludge material.

[0130] In a preferred embodiment, the height from the bottom of the furnace body 2 to the bottom of the air inlet chamber 3 is 1 / 3 of the vertical height of the furnace body 2. This arrangement has the advantages of achieving more uniform airflow distribution, helping the gas flow evenly within the furnace body 2 and avoiding local overheating or cooling. Furthermore, it allows the purified gas to fully contact the oil sludge material after entering the furnace body 2, improving the purification effect and increasing the mass transfer efficiency during the treatment process.

[0131] In a preferred implementation, the furnace body 2 includes a heating zone and a constant temperature zone. For example, the two ends of the furnace body 2 are heating zones, and the middle part of the furnace body 2 is a constant temperature zone. The heating zone is equipped with heating elements, such as resistance wires, heating tubes or other forms of heating devices, which are not limited in this application. These heating devices heat the furnace body 2 to the required working temperature through current conduction or radiation. The constant temperature zone is used to maintain a stable working temperature. In the constant temperature zone, insulation materials are usually used to reduce energy loss and ensure that the internal temperature is maintained at the required constant level. This area usually has good thermal isolation properties to prevent heat from being transferred outward. For example, in this embodiment, the furnace body 2 is made of high-purity alumina fiber material, which can not only isolate other components on the furnace body 2 from aging damage caused by high-temperature heat conduction, but also has good thermal stability and saves energy and reduces consumption.

[0132] Figure 8 shows a schematic cross-sectional view of furnace body 2. A lifting plate 21 is also provided within furnace body 2. This plate is used to stir the NdFeB waste sludge within the furnace body 2. The axial direction of the lifting plate 21 aligns with the axial direction of the furnace body 2. As the furnace body 2 rotates, the lifting plate 21 stirs the waste sludge within the furnace body 2, ensuring full contact between the sludge and the purified gas, thereby fully purifying the sludge within the furnace body 2. Furthermore, the design of the lifting plate 21 can improve the gas flow pattern within the furnace body. For example, the lifting plate 21 can help disperse the gas flow path and reduce airflow resistance, achieving more uniform gas distribution and better purification results.

[0133] The lifting plate 21 can be set to a flat, spiral, conical, trapezoidal, wavy or other shapes. The present solution preferably uses a spiral lifting plate 21. Due to the spiral shape design, the spiral lifting plate 21 can push the sludge waste material upward along the spiral path, which helps to achieve a better mixing effect, so that the sludge waste material and the purified gas can be more fully in contact and interact with each other, thereby improving the reaction efficiency and purification effect. In addition, the spiral lifting plate 21 generates shear force and stirring action during the rotational motion, further promoting the mixing and stirring inside the sludge material, helping to evenly distribute the temperature and composition, and achieving more uniform reaction and purification results during the treatment process. Finally, the spiral shape of the spiral lifting plate 21 increases the surface area and can provide more heat conduction contact surfaces, thereby accelerating the heat energy transfer and the heating rate of the sludge material, which helps to improve the treatment efficiency and energy utilization.

[0134] The air inlet chamber 3 is used to introduce external gas. For example, nitrogen, argon, oxygen, carbon dioxide, hydrogen and other gases can be introduced into the air inlet chamber 3. Through the air inlet chamber 3, the operator can control and adjust parameters such as the type, flow rate and pressure of the gas entering the furnace body 2. In order to facilitate the adjustment and monitoring of the gas flow entering the air inlet chamber 3, as shown in Figures 6-7, a gas flow meter 31 is connected to the air inlet pipe of the air inlet chamber 3. The gas flow meter 31 is fixed to the side wall of the lower box 13. For example, the flow rate of the purified gas is set to 60 to 600 ml / min. In this example, a three-way gas flow meter 31 can be selected. The three-way gas flow meter 31 has an air inlet and two air outlets. The air inlet is used to connect to the gas source, while the air outlet is used to measure the forward and reverse flow of the gas respectively.

[0135] The exhaust chamber 4 is used to discharge waste gases generated during the processing process. Through the exhaust chamber 4, the waste gases can be safely collected and directed to a suitable treatment system, such as purification equipment or an exhaust gas treatment device. The furnace door of the exhaust chamber 4 is also equipped with an exhaust valve 41, which is preferably an outward-swinging type. The exhaust valve 41 is used to control the discharge and flow of waste gases within the furnace body 2. By opening or closing the exhaust valve 41, the operator can adjust the gas flow in the exhaust chamber 4 and control the pressure and atmosphere inside the furnace body 2.

[0136] As shown in Figure 7, a driving device 5 for driving the furnace body 2 to rotate is also provided in the housing 1. For example, the driving device 5 controls the rotation speed of the furnace body 2 to be 5-15r / min. In one example, the driving device 5 includes a motor 51, a gear 52 and a ring gear 53, and the motor 51 is fixed in the middle housing 12. The ring gear 53 is sleeved on the outer peripheral side wall of the air inlet chamber 3 or the exhaust chamber 4, and the output shaft of the motor 51 is connected to the gear 52, or the motor 51 and the gear 52 can also be connected through a reducer, and the gear 52 is meshed with the ring gear 53. The above is only an example of the driving device 5. The driving device 5 can also drive other transmission devices to realize the rotation of the furnace body 2 through the motor 51, such as the cooperation of a sprocket and a chain, or the cooperation of a pulley and a belt, etc. The rotating component can also be driven to rotate by a hydraulic system, and the rotating component then drives the furnace body 2 to rotate. This application does not limit the specific form of the driving device 5.

[0137] As shown in Figure 8, a pressure relief device 6 is disposed above the furnace body 2. In one example, the pressure relief device 6 includes an outward-swinging pressure relief valve. The pressure relief valve is connected to the furnace body 2 and can monitor and control the pressure inside the rotary kiln. When the pressure exceeds a set value, the pressure relief valve automatically releases gas to prevent the internal pressure from rising to a dangerous level, thereby helping to prevent safety risks such as explosion, equipment damage, and personal injury. For example, the pressure relief valve is set to a pressure of 1-2 atm. When the pressure exceeds this set value, the pressure relief valve automatically releases gas.

[0138] The pressure relief valve can be connected to the furnace body 2 by installing a flange on the furnace body 2, and then connecting the pressure relief valve to the furnace body 2 through the flange. Sealing gaskets and bolts are used at the flange connection to ensure the sealing and stability of the connection. A welding interface can also be reserved inside the furnace body 2, and the pressure relief valve can be connected to the interface by welding. It is also possible to provide appropriate threaded interfaces for both the furnace body 2 and the pressure relief valve, and directly thread the pressure relief valve into the threaded hole in the furnace body 2, and seal the threaded connection. The above is an example of the connection method of the pressure relief valve to the furnace body 2, and this application does not limit this.

[0139] The vacuum meter 7 is also set above the furnace body 2. The vacuum meter 7 can be used to monitor the vacuum level in the rotary kiln in real time. The vacuum meter 7 provides an accurate measurement of the gas pressure in the working environment, so that the operator can understand the vacuum level of the system. For example, the vacuum level can be set to 10 -1 ~10-4 Pa.

[0140] In a preferred embodiment, after the oil sludge material in the furnace body 2 is purified, a lifting cylinder 8 is further provided inside the lower housing 13 to facilitate removal of the purified oil sludge material from the furnace body 2. As shown in FIG9 , the lifting cylinder 8 is fixed inside the lower housing 13, and the piston rod of the lifting cylinder 8 is rotatably connected to the bottom of the middle housing 12. When the lifting cylinder 8 is activated, the middle housing 12 is tilted and raised upward with the hinge side as the rotation axis, simultaneously driving the furnace body 2 in the upper housing 11 to tilt. A material receiving device is provided at the outlet of the exhaust chamber 4, and the purified oil sludge material can be recovered.

[0141] As shown in Figures 6 and 7, the vacuum atmosphere rotary kiln also includes a starting assembly 9, which is disposed on the side wall of the lower housing 13. The starting assembly 9 can be used to control the start of the motor 51 and the lifting cylinder 8. For example, the starting assembly 9 can include buttons with different functions, such as a start button, a stop button, and an emergency stop button. By pressing the start button, a start signal can be sent, triggering the operation of related equipment and mechanical components. The emergency stop button is used to quickly stop the operation of the furnace body 2 in an emergency. When an accident or dangerous situation occurs, simply pressing the emergency stop button immediately cuts off the power supply and stops the operation of the furnace body 2.

[0142] A control assembly 10 is also provided on the side wall of the housing 1. For example, the control assembly 10 includes a temperature controller for monitoring and controlling the temperature inside the furnace body 2. A regulator may be provided on the side wall of the housing 1, and a temperature sensor may be provided inside the housing 1. The temperature of the furnace body 2 inside the housing 1 may be automatically adjusted within a set temperature range to maintain a stable temperature inside the furnace body 2.

[0143] The following describes in detail a highly efficient purification method for RFeB-type oily sludge waste material in conjunction with specific embodiments. NdFeB oily sludge waste material is used as an example of RFeB-type oily sludge waste material. The contents of the various components in the NdFeB oily sludge waste material are shown in Table 1. Figure 10 shows a schematic diagram of the appearance of the NdFeB oily sludge waste material, and Figure 11 shows the optical microscopic morphology of the NdFeB oily sludge waste material.

[0144] Example 1

[0145] An efficient purification method for NdFeB oil sludge waste, comprising:

[0146] Step 1: Take the thin paste-like NdFeB oil sludge and put it into a stainless steel mesh plate (40 cm * 40 cm), spread it flat and place it in a circulating air oven for drying. The thickness of the oil sludge should not exceed 5 cm. Set the oven temperature to 100±2℃ and the drying time to 2 hours. The appearance of the NdFeB oil sludge waste after drying is shown in Figure 12.

[0147] Step 2: Weigh 5 kg of dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 60% ethanol and 40% butanone solution (all solutions are expressed in volume percentages unless otherwise specified) as diluents. The total amount of diluent is 15 liters (9 liters of ethanol and 6 liters of butanone solution).

[0148] Step 3: Set the agitator speed in the mixing tank to 30 rpm and the mixing time to 30 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0149] Step 4: After the oil sludge is evenly mixed, use a 4-piston viscosity cup to measure the viscosity of the oil sludge slurry, which is 80 seconds;

[0150] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the slurry level in the mixing barrel. Set the centrifugal speed of the mixing basket to 150 rpm and the centrifugal time to 1 minute. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0151] Step 6: Let the uniform oil sludge slurry after filtration in the mixing barrel stand for 1 hour, pour out the clear liquid on the top, and put the oil sludge material at the bottom into the vacuum atmosphere rotary furnace body. Use the clear liquid to rinse the oil sludge material in the mixing barrel several times, and pour the rinsing liquid into the furnace body together (the treatment of the clear liquid here can be determined according to the rare earth and Fe content in the clear liquid. It can also be recycled and reused as a diluent). The volume of the oil sludge and clear liquid should be less than 1 / 2 of the furnace volume.

[0152] Step 7: Close the exhaust chamber door, open the exhaust port (i.e. exhaust valve) on the exhaust chamber door, set the furnace temperature to 40°C, and bake for 1 hour;

[0153] Step 8: Turn on the furnace body rotation switch, start the drive device to drive the furnace body to rotate, and continue baking for 30 minutes while the material lifting plate stirs;

[0154] Step 9: Raise the furnace temperature to 100°C and introduce argon at a flow rate of 70 ml / min. Continue introducing argon for 30 minutes after the temperature stabilizes.

[0155] Step 10: Turn off the argon gas, close the exhaust port on the furnace door, turn on the rotary kiln mechanical pump and diffusion pump to start vacuuming the furnace body;

[0156] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen and argon mixed gas (hydrogen and argon volume ratio is 20:80). At the same time, increase the furnace temperature to 300°C. After the temperature stabilizes, continue to introduce hydrogen and argon mixed gas, and control the gas flow rate at 40 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0157] Step 12: Turn off the furnace heater, the hydrogen-argon mixed gas, and the pressure limiting valve. When the temperature in the furnace drops to 30±5°C, introduce argon protection again;

[0158] Step 13: Turn on the furnace tilt switch and the lift cylinder to tilt the furnace. Pour the treated sludge powder into a sealed stainless steel tank. This completes the pre-treatment of the NdFeB sludge waste for oil removal and impurity removal, achieving efficient purification of the NdFeB sludge waste. Figure 13 shows the appearance of the NdFeB sludge waste after efficient purification.

[0159] Example 2

[0160] An efficient purification method for NdFeB oil sludge waste, comprising:

[0161] Step 1: Same as step 1 of Example 1;

[0162] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 60% ethanol, 35% butanone, and 5% (by mass) 1% ammonia solution (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 12 liters.

[0163] Step 3: Set the agitator speed in the mixing tank to 50 rpm and the mixing time to 60 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0164] Step 4: After the oil sludge is evenly mixed, the viscosity of the oil sludge is measured using a 4-count viscosity cup and the viscosity is 95 seconds;

[0165] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 230 rpm and the centrifugal time to 3 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0166] Step 6: Let the uniform oil sludge slurry after filtration in the mixing barrel stand for 2 hours, pour out the clear liquid on the top, and put the oil sludge material at the bottom into the vacuum atmosphere rotary furnace body. Use the clear liquid to rinse the oil sludge material in the mixing barrel several times, and pour the rinsing liquid into the furnace body together (the treatment of the clear liquid here can be determined according to the rare earth and Fe content in the clear liquid. It can also be recycled and reused as a diluent). The volume of the oil sludge and clear liquid should be less than 1 / 2 of the furnace volume.

[0167] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 60°C, and bake for 2 hours;

[0168] Step 8: Turn on the furnace body rotation switch, start the drive device to drive the furnace body to rotate, and continue baking for 60 minutes while the material lifting plate stirs;

[0169] Step 9: Raise the furnace temperature to 200°C and introduce argon at the same time, controlling the flow rate at 90 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0170] Step 10: Same as step 10 in Example 1;

[0171] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 30:70). At the same time, increase the temperature to 380°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas, and control the gas flow rate at 50 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0172] Steps 12-13: Same as steps 12 to 13 of Example 1.

[0173] Example 3

[0174] An efficient purification method for NdFeB oil sludge waste, comprising:

[0175] Step 1: Same as step 1 of Example 1;

[0176] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 95% ethanol and 5% gasoline (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0177] Step 3: Set the agitator speed in the mixing tank to 80 rpm and the mixing time to 60 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0178] Step 4: After the oil sludge is evenly mixed, use a 4-piston viscosity cup to measure the viscosity of the oil sludge slurry for 100 seconds;

[0179] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 280 rpm and the centrifugal time to 5 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0180] Step 6: Let the uniform oil sludge slurry after filtration in the mixing barrel stand for 3 hours, pour out the clear liquid on top, and put the oil sludge material at the bottom into the vacuum atmosphere rotary furnace body. Use the clear liquid to rinse the oil sludge material in the mixing barrel several times, and pour the rinsing liquid into the furnace body together (the treatment of the clear liquid here can be determined according to the rare earth and Fe content in the clear liquid. It can also be recycled and reused as a diluent). The volume of the oil sludge and clear liquid should be less than 1 / 2 of the furnace body volume.

[0181] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 40°C, and bake for 3 hours;

[0182] Step 8: Turn on the furnace body rotation switch, start the drive device to drive the furnace body to rotate, and continue baking for 90 minutes while the material lifting plate stirs;

[0183] Step 9: Raise the furnace temperature to 150°C and introduce argon at a flow rate of 110 ml / min. Continue introducing argon for 120 minutes after the temperature stabilizes.

[0184] Step 10: Same as step 10 in Example 1;

[0185] Step 11: When the vacuum degree in the furnace reaches 10 -4Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 40:60). At the same time, increase the temperature to 300°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas, and control the gas flow rate at 50 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0186] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0187] Example 4

[0188] An efficient purification method for NdFeB oil sludge waste, comprising:

[0189] Step 1: Same as step 1 of Example 1;

[0190] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 60% ethanol, 20% ethyl acetate and 20% 1% ammonia solution (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 12 liters.

[0191] Step 3: Same as step 3 of Example 3;

[0192] Step 4: After the oil sludge is evenly mixed, the viscosity of the oil sludge is measured using a 4-count viscosity cup and the viscosity is 95 seconds;

[0193] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 230 rpm and the centrifugal time to 5 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil sludge slurry.

[0194] Steps 6 to 8: the same as Steps 6 to 8 in Example 2;

[0195] Step 9: Raise the furnace temperature to 200°C and introduce argon at a flow rate of 100 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0196] Step 10: Same as step 10 in Example 1;

[0197] Step 11: When the vacuum degree in the furnace reaches 10 -4Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, start to slowly introduce hydrogen and argon mixed gas, and at the same time, increase the temperature to 400℃. After the temperature stabilizes, continue to introduce hydrogen and argon mixed gas (the volume ratio of hydrogen to argon is 50:50), and control the gas flow rate at 60 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0198] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0199] The oxygen and nitrogen content, carbon and sulfur content and composition analysis of the treated sludge powder are shown in Table 2

[0200] Example 5

[0201] An efficient purification method for NdFeB oil sludge waste, comprising:

[0202] Step 1: Same as step 1 of Example 1;

[0203] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 80% ethanol and 20% ethyl acetate solutions (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0204] Step 3: Set the agitator speed in the mixing tank to 100 rpm and the stirring time to 60 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0205] Step 4: Same as step 4 in Example 3;

[0206] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 230 rpm and the centrifugal time to 8 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0207] Step 6: Same as step 6 in Example 3;

[0208] Step 7 to Step 8: Same as Step 7 to Step 8 of Example 2;

[0209] Step 9: Raise the furnace temperature to 300°C and introduce argon at a flow rate of 90 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0210] Step 10: Same as step 10 in Example 1;

[0211] Step 11: When the vacuum degree in the furnace reaches 10-4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 20:80). At the same time, increase the temperature to 500°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas, and control the gas flow rate at 70 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0212] Step 12: Steps 12 to 13 are the same as those in Example 1.

[0213] Example 6

[0214] An efficient purification method for NdFeB oil sludge waste, comprising:

[0215] Step 1: Same as step 1 of Example 1;

[0216] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 90% ethanol and 10% petroleum ether (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 5 liters.

[0217] Step 3: Set the agitator speed in the mixing tank to 100 rpm and the mixing time to 120 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0218] Step 4: After the oil sludge is evenly mixed, use a 4-piston viscosity cup to measure the viscosity of the oil sludge slurry, which is 120 seconds;

[0219] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 380 rpm and the centrifugal time to 8 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0220] Step 6: Same as step 6 in Example 3;

[0221] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 50°C, and bake for 4 hours;

[0222] Step 8: Turn on the furnace body rotation switch, start the drive device to drive the furnace body to rotate, and continue baking for 90 minutes while the material lifting plate stirs;

[0223] Step 9: Same as step 9 in Example 3;

[0224] Step 10: Same as step 10 in Example 1;

[0225] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, start to slowly introduce hydrogen and argon mixed gas, and at the same time, increase the temperature to 320℃. After the temperature stabilizes, continue to introduce hydrogen and argon mixed gas, and control the gas flow rate at 70ml / min. Treat for 120 minutes under constant temperature and pressure conditions;

[0226] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0227] Example 7

[0228] An efficient purification method for NdFeB oil sludge waste, comprising:

[0229] Step 1: Same as step 1 of Example 1;

[0230] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 70% ethylene glycol and 30% ethyl acetate solutions (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 15 liters.

[0231] Step 3: Set the agitator speed in the mixing tank to 80 rpm and the mixing time to 100 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0232] Step 4: Same as step 4 in Example 3;

[0233] Step 5: Same as step 5 of Example 5;

[0234] Step 6: Same as step 6 in Example 3;

[0235] Step 7 to Step 8: Same as Step 7 to Step 8 of Example 2;

[0236] Step 9: Same as step 9 in Example 5;

[0237] Step 10: Same as step 10 in Example 1;

[0238] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 50:50). At the same time, increase the temperature to 480°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas, and control the gas flow rate at 50 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0239] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0240] Example 8

[0241] An efficient purification method for NdFeB oil sludge waste, comprising:

[0242] Step 1: Same as step 1 of Example 1;

[0243] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 70% ethanol, 15% ethyl acetate and 15% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0244] Step 3: Same as step 3 of Example 7;

[0245] Step 4: Same as step 4 in Example 3;

[0246] Steps 5 to 6: the same as Steps 5 to 6 of Example 5;

[0247] Step 7 to Step 8: Same as Step 7 to Step 8 of Example 4;

[0248] Step 9: Raise the furnace temperature to 280°C and introduce argon at a flow rate of 110 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0249] Step 10: Same as step 10 in Example 1;

[0250] Step 11: Same as step 11 in Example 7;

[0251] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0252] Example 9

[0253] An efficient purification method for NdFeB oil sludge waste, comprising:

[0254] Step 1: Same as step 1 of Example 1;

[0255] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 80% ethylene glycol, 15% butanone, and 5% petroleum ether (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 8 liters.

[0256] Step 3: Set the agitator speed in the mixing tank to 90 rpm and the mixing time to 100 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0257] Step 4: After the oil sludge is evenly mixed, the viscosity of the oil sludge is measured using a 4-well viscosity cup and is 110 seconds;

[0258] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 250 rpm and the centrifugal time to 8 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0259] Step 6: Same as step 6 in Example 3;

[0260] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 50°C, and bake for 3 hours;

[0261] Step 8 to Step 9: Same as Step 8 to Step 9 of Example 3;

[0262] Step 10: Same as step 10 in Example 1;

[0263] Step 11: Same as step 11 in Example 6;

[0264] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0265] Example 10

[0266] An efficient purification method for NdFeB oil sludge waste, comprising:

[0267] Step 1: Same as step 1 of Example 1;

[0268] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 85% ethylene glycol, 5% gasoline, and 10% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 8 liters.

[0269] Step 3: Same as step 3 of Example 9;

[0270] Step 4: Same as step 4 in Example 3;

[0271] Step 5: Same as step 5 of Example 9;

[0272] Step 6: Same as step 6 in Example 3;

[0273] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 40°C, and bake for 4 hours;

[0274] Step 8 to Step 9: Same as Step 8 to Step 9 in Example 3;

[0275] Step 10: Same as step 10 in Example 1;

[0276] Step 11: Same as step 11 in Example 6;

[0277] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0278] Example 11

[0279] An efficient purification method for NdFeB oil sludge waste, comprising:

[0280] Step 1: Same as step 1 of Example 1;

[0281] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 90% ethylene glycol and 10% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0282] Step 3: Same as step 3 of Example 7;

[0283] Step 4: Same as step 4 in Example 3;

[0284] Step 5: Same as step 5 of Example 9;

[0285] Step 6: Same as step 6 in Example 3;

[0286] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 50°C, and bake for 2 hours;

[0287] Step 8: Same as step 8 in Example 2;

[0288] Step 9: Raise the furnace temperature to 280°C and introduce argon at a flow rate of 100 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0289] Step 10: Same as step 10 in Example 1;

[0290] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 50:50). At the same time, increase the temperature to 450°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas, and control the gas flow rate at 60 ml / min. Treat for 60 minutes under constant temperature and pressure conditions;

[0291] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0292] Example 12

[0293] An efficient purification method for NdFeB oil sludge waste, comprising:

[0294] Step 1: Same as step 1 of Example 1;

[0295] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 75% isopropyl alcohol, 10% gasoline, and 15% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 5 liters.

[0296] Step 3: Same as step 3 in Example 6;

[0297] Step 4: Same as step 4 in Example 6;

[0298] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 350 rpm and the centrifugal time to 10 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil sludge slurry.

[0299] Step 6: Same as step 6 in Example 3;

[0300] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 40°C, and bake for 5 hours;

[0301] Step 8: Same as step 8 in Example 3;

[0302] Step 9: Raise the furnace temperature to 150°C and introduce argon at a flow rate of 100 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0303] Step 10: Same as step 10 in Example 1;

[0304] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace upper pressure valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 50:50). At the same time, increase the temperature to 450°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas and treat for 120 minutes under constant temperature and pressure conditions;

[0305] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0306] Example 13

[0307] An efficient purification method for NdFeB oil sludge waste, comprising:

[0308] Step 1: Same as step 1 of Example 1;

[0309] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 80% isopropyl alcohol, 10% ethyl acetate, and 10% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 12 liters.

[0310] Step 3: Same as step 3 of Example 3;

[0311] Step 4: Same as step 4 in Example 2;

[0312] Step 5: Same as step 5 of Example 4;

[0313] Steps 6 to 8: the same as Steps 6 to 8 in Example 2;

[0314] Step 9: Raise the furnace temperature to 250°C and introduce argon at a flow rate of 110 ml / min. Continue introducing argon for 120 minutes after the temperature stabilizes.

[0315] Step 10: Same as step 10 in Example 1;

[0316] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace upper pressure valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 50:50). At the same time, increase the temperature to 320°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas and treat at constant temperature and pressure for 60 minutes;

[0317] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0318] Example 14

[0319] An efficient purification method for NdFeB oil sludge waste, comprising:

[0320] Step 1: Same as step 1 of Example 1;

[0321] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 85% isopropyl alcohol and 15% butanone (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0322] Step 3 to Step 4: Same as Step 3 to Step 4 of Example 3;

[0323] Step 5: Same as step 5 of Example 5;

[0324] Steps 6 to 8: the same as Steps 6 to 8 in Example 2;

[0325] Step 9: Raise the furnace temperature to 250°C and introduce argon at a flow rate of 100 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0326] Step 10: Same as step 10 in Example 1;

[0327] Step 11: Same as step 11 of Example 11;

[0328] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0329] Example 15

[0330] An efficient purification method for NdFeB oil sludge waste, comprising:

[0331] Step 1: Same as step 1 of Example 1;

[0332] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 90% isopropyl alcohol and 10% butanone (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 12 liters.

[0333] Step 3: Same as step 3 of Example 3;

[0334] Step 4: Same as step 4 in Example 2;

[0335] Step 5: Same as step 5 of Example 4;

[0336] Step 6: Same as step 6 in Example 2;

[0337] Step 7 to Step 8: Same as Step 7 to Step 8 of Example 2;

[0338] Step 9: Raise the furnace temperature to 250°C and introduce argon at a flow rate of 90 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0339] Step 10: Same as step 10 in Example 1;

[0340] Step 11: Same as step 11 in Example 2;

[0341] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0342] Example 16

[0343] An efficient purification method for NdFeB oil sludge waste, comprising:

[0344] Step 1: Same as step 1 of Example 1;

[0345] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 90% isopropyl alcohol, 5% petroleum ether, and 5% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0346] Step 3: Set the agitator speed in the mixing tank to 90 rpm and the mixing time to 60 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0347] Step 4: Same as step 4 of Example 9;

[0348] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 230 rpm and the centrifugal time to 6 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0349] Step 6: Same as step 6 in Example 2;

[0350] Step 7: Same as step 7 of Example 9;

[0351] Step 8 to Step 9: Same as Step 8 to Step 9 of Example 3;

[0352] Step 10: Same as step 10 in Example 1;

[0353] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace pressure limiting valve, set the pressure of the pressure limiting valve to 1-2atm, start to slowly introduce hydrogen and argon mixed gas (the volume ratio of hydrogen and argon is 50:50), and at the same time, increase the temperature to 380℃. After the temperature stabilizes, continue to introduce hydrogen and argon mixed gas, and control the gas flow rate at 50ml / min. Treat for 120 minutes under constant temperature and pressure conditions;

[0354] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0355] Example 17

[0356] An efficient purification method for NdFeB oil sludge waste, comprising:

[0357] Step 1: Same as step 1 of Example 1;

[0358] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 95% isopropyl alcohol and 5% ethyl acetate (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 12 liters.

[0359] Step 3: Same as step 3 of Example 3;

[0360] Step 4: Same as step 4 in Example 2;

[0361] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 280 rpm and the centrifugal time to 6 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0362] Step 6: Same as step 6 in Example 2;

[0363] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 60°C, and bake for 3 hours;

[0364] Step 8: Same as step 8 in Example 2;

[0365] Step 9: Same as step 9 of Example 15;

[0366] Step 10: Same as step 10 in Example 1;

[0367] Step 11: Same as step 11 of Example 13;

[0368] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0369] Example 18

[0370] An efficient purification method for NdFeB oil sludge waste, comprising:

[0371] Step 1: Same as step 1 of Example 1;

[0372] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 60% isopropyl alcohol and 40% 1% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0373] Step 3: Set the agitator speed in the mixing tank to 80 rpm and the mixing time to 80 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed in liquid state.

[0374] Step 4: Same as step 4 in Example 3;

[0375] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 260 rpm and the centrifugal time to 6 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil slurry.

[0376] Step 6: Same as step 6 in Example 3;

[0377] Step 7 to Step 8: Same as Step 7 to Step 8 of Example 2;

[0378] Step 9: Raise the furnace temperature to 250°C and introduce argon at a flow rate of 110 ml / min. Continue introducing argon for 60 minutes after the temperature stabilizes.

[0379] Step 10: Same as step 10 in Example 1;

[0380] Step 11: Same as step 11 in Example 2;

[0381] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0382] Example 19

[0383] An efficient purification method for NdFeB oil sludge waste, comprising:

[0384] Step 1: Same as step 1 of Example 1;

[0385] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 80% ethyl acetate and 20% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 14 liters.

[0386] Step 3: Set the agitator speed in the mixing tank to 60 rpm and the mixing time to 80 minutes. Slowly add the diluent while turning on the agitator and stirring while adding until the oil sludge is evenly mixed under liquid conditions;

[0387] Step 4: Same as step 4 in Example 3;

[0388] Step 5: Turn off the agitator, separate the mixing basket from the mixing barrel, fix the mixing basket on the disc below the drive motor, lower the mixing barrel by 10 cm, and keep the mixing basket about 10 cm away from the liquid surface in the mixing barrel. Set the centrifugal speed of the mixing basket to 260 rpm and the centrifugal time to 8 minutes. Shake off the remaining slurry on the mixing basket. The residue at the bottom of the mixing basket is the impurities in the oil sludge slurry.

[0389] Step 6: Same as step 6 in Example 3;

[0390] Step 7: Same as step 7 in Example 6;

[0391] Step 8: Same as step 8 in Example 2;

[0392] Step 9: Raise the furnace temperature to 270°C and introduce argon at a flow rate of 100 ml / min. Continue introducing argon for 80 minutes after the temperature stabilizes.

[0393] Step 10: Same as step 10 in Example 1;

[0394] Step 11: When the vacuum degree in the furnace reaches 10 -4 Pa, turn off the mechanical pump and diffusion pump, open the furnace upper pressure valve, set the pressure of the pressure limiting valve to 1-2atm, and slowly introduce hydrogen-argon mixed gas (the volume ratio of hydrogen to argon is 50:50). At the same time, increase the temperature to 420°C. After the temperature stabilizes, continue to introduce hydrogen-argon mixed gas and treat at constant temperature and pressure for 60 minutes;

[0395] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0396] Example 20

[0397] An efficient purification method for NdFeB oil sludge waste, comprising:

[0398] Step 1: Same as step 1 of Example 1;

[0399] Step 2: Weigh 5 kg of the dried oil sludge and pour it into the mixing basket of the mixing barrel. Measure 60% isopropyl alcohol, 10% petroleum ether, and 30% ammonia water (all solutions are expressed in volume percentages unless otherwise specified) as diluents and add them to the oil sludge in the mixing basket in sequence. The total amount of diluent is 10 liters.

[0400] Step 3 to Step 4: Same as Step 3 to Step 4 in Example 6;

[0401] Step 5: Same as step 5 of Example 12;

[0402] Step 6: Same as step 6 in Example 3;

[0403] Step 7: Close the oven door, open the exhaust port on the oven door, set the oven temperature to 50°C, and bake for 5 hours;

[0404] Step 8 to Step 9: Same as Step 8 to Step 9 of Example 3;

[0405] Step 10: Same as step 10 in Example 1;

[0406] Step 11: Same as step 11 in Example 6;

[0407] Steps 12 to 13: the same as steps 12 to 13 of Example 1.

[0408] Comparative Example 1

[0409] A method for treating NdFeB oil sludge waste, comprising:

[0410] Anhydrous ethanol with a volume ratio of 1:10 was added to the NdFeB sludge waste, and vacuum distillation was performed at 100°C. Then, dilute nitric acid with a mass fraction of 3% was added to the distilled powder, and ultrasonic cleaning and magnetic separation were repeated 10 times. The obtained product was then ultrasonically cleaned 5 times by adding anhydrous ethanol and 5 times by adding acetone, and then dried to obtain the treated sludge powder.

[0411] Comparative Example 2

[0412] A method for treating NdFeB oil sludge waste, comprising:

[0413] An excess of 2 mol / L hydrochloric acid solution was added to the NdFeB sludge waste, and the mixture was heated in a water bath at 80°C for 30 minutes. After filtration, ammonia water (pH 2) and oxalic acid were added to the sludge again, and the mixture was heated in a water bath at 70°C for 30 minutes. After centrifugation, water washing, and precipitation, the precipitate was loaded into a muffle furnace and calcined at 900°C for 180 minutes to obtain the treated sludge powder.

[0414] Comparative Example 3

[0415] A method for treating NdFeB oil sludge waste, comprising:

[0416] OP emulsifier and ethanol solution are added to the NdFeB sludge waste and loaded into a centrifuge for centrifugation three times, each time for 30 minutes; the mixed solution is then precipitated and distilled, and a hydrochloric acid-ethanol mixed solution is added to the precipitate after treatment for washing, with a hydrochloric acid concentration of 1wt%, and washing for 30 minutes. The washing is repeated three times and the treated sludge powder is obtained after drying.

[0417] Comparative Example 4

[0418] A method for treating NdFeB oil sludge waste, comprising:

[0419] Gasoline was added to the NdFeB sludge waste and placed in a ball mill. The sludge was ball milled for 5 hours, and then 15 vol% acetic acid solution was added. The sludge was ultrasonicated under a magnetic field for 20 minutes. After magnetic separation, the liquid was poured out. The sludge was placed in a centrifuge tube and anhydrous ethanol was added. The sludge was centrifuged for 10 minutes. The operation was repeated 5 times. Finally, the powder was placed in a vacuum drying oven and dried for 2 hours to obtain the treated sludge powder.

[0420] Comparative Example 5

[0421] A method for treating NdFeB oil sludge waste, comprising:

[0422] Deionized water was added to the NdFeB sludge waste material and stirred evenly, and the material was evaporated to dryness in a constant temperature water bath at 80°C. Acetone was added to the distilled powder for ultrasonic cleaning three times, and then anhydrous ethanol was added for ultrasonic cleaning. After removing the washing liquid, the material was vacuum dried at 70°C to obtain the treated sludge powder.

[0423] Comparative Example 6

[0424] A method for treating NdFeB oil sludge waste, comprising:

[0425] A mixed solution of 0.2 g / L sodium hydroxide, 3% OP emulsifier and ethanol was added to the NdFeB sludge waste, and ultrasonic cleaning was performed for 30 minutes. The cleaning was repeated three times. After cleaning, the sludge was washed with ethanol again, and magnetic separation was performed at the same time. The separated material was vacuum dried to obtain the treated sludge powder.

[0426] Example 1-20 adopts an efficient purification method for NdFeB oil sludge waste and Comparative Example 1-6 adopts a treatment method for NdFeB oil sludge waste. The analysis of oxygen, hydrogen, nitrogen, carbon, sulfur and other components of the treated oil sludge powder is shown in Table 1.

[0427] As shown in Table 1, the purification methods of Examples 1-20 achieved over 95% oil removal (C and H content in the sludge) from NdFeB waste sludge, reduced the sludge's oxygen content by approximately 60-80%, and achieved virtually no loss of rare earth elements such as neodymium during the treatment process. The treatment methods of Comparative Examples 1-6, on the one hand, showed significant loss of rare earth elements; on the other hand, the C and H content in the sludge was high, indicating poor oil removal.

[0428] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this application can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this application can be achieved. This application is not limited here.

[0429] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0430] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An efficient purification method for RFeB oily sludge waste, characterized in that: R is one or more rare earth elements; the method comprises the following steps: The pre-treated RFeB oil sludge waste is placed in a vacuum gas rotary kiln with inert gas and purified at 100-300°C; When the vacuum degree of the vacuum gas rotary kiln reaches a set threshold, purified gas is introduced into the vacuum gas rotary kiln to perform secondary purification on the RFeB type oily sludge waste material after the primary purification at 300-500°C.

2. The method according to claim 1, characterized in that The primary purification comprises: Raise the temperature of the vacuum gas rotary furnace and introduce inert gas into the vacuum gas rotary furnace until the temperature of the vacuum gas rotary furnace is stabilized at 100-300°C; The inert gas is continuously introduced for 30 to 120 minutes to purify the pretreated RFeB type oily sludge waste.

3. The method according to claim 2, characterized in that The flow rate of the inert gas is 70-110 mL / min.

4. The method according to claim 1, wherein The secondary purification comprises: The vacuum gas rotary furnace is evacuated until the vacuum degree in the vacuum gas rotary furnace reaches a set threshold value, and the pressure of the pressure limiting valve of the vacuum gas furnace is set to 1-2 atm; Raise the temperature of the vacuum gas rotary furnace and introduce purified gas into the vacuum gas rotary furnace until the temperature of the vacuum gas rotary furnace stabilizes at 300-500°C; The purified gas is continuously introduced for 60 to 120 minutes to allow the RFeB type oily sludge waste to undergo secondary purification after the primary purification.

5. The method according to claim 4, characterized in that The purified gas is a mixed gas of hydrogen and inert gas, wherein the volume ratio of hydrogen to inert gas is 20:80 to 50:

50.

6. The method according to claim 5, characterized in that The flow rate of the purified gas is 30-70 mL / min.

7. The method according to claim 1, characterized in that The RFeB oily sludge waste material is pretreated by at least one of drying, activation and pre-purification methods.

8. The method according to claim 7, characterized in that The activation comprises: The dried RFeB type oily sludge waste material and the diluent are added into the oily sludge material mixing and filtering device and stirred, so that the dried RFeB type oily sludge waste material and the diluent are fully contacted to realize activation.

9. The method according to claim 8, characterized in that Calculated by volume percentage, the diluent includes at least two of 60% to 95% of alcohol compounds, 5% to 80% of ketone or ester compounds, 5% to 10% of petroleum derivatives, and 5% to 40% of weak alkaline solution.

10. The method according to claim 9, characterized in that The alcohol compound is a lower alcohol compound having no more than three carbon atoms.

11. The method according to claim 10, characterized in that The petroleum derivatives include at least one of gasoline and petroleum ether.

12. The method according to claim 11, characterized in that Based on the mass of the dried RFeB oily sludge waste, the amount of diluent added is 1 to 3 L / kg.

13. The method according to claim 12, characterized in that The stirring rate is 30-100 r / min, and the stirring time is 30-120 min.

14. The method according to claim 7, wherein: The pre-purification comprises: The activated RFeB oil sludge waste is centrifuged and baked to achieve pre-purification.

15. The method according to claim 14, characterized in that The baking temperature is 40-50° C., and the baking time is 1-5 hours.

16. The method according to claim 15, characterized in that The RFeB oil sludge waste is baked at 40-50°C for 30-90 minutes under stirring.

17. The method according to claim 14, characterized in that The centrifugal conditions are as follows: a centrifugal rate of 150 to 380 r / min and a centrifugal time of 1 to 10 min.

18. The method according to any one of claims 8 to 13, characterized in that: The oil sludge material mixing filtering device comprises: Chassis; A mixing barrel is provided in the chassis, and a discharge channel communicating with the interior is provided below the mixing barrel; A mixing basket, used for holding RFeB oily sludge waste, the mixing basket being detachably connected to the chassis; an agitator, disposed in the mixing barrel, for agitating the RFeB oily sludge waste in the mixing barrel; A drive motor is provided on the chassis above the mixing barrel, and the drive motor is connected to the stirrer to drive the stirrer to rotate; The vibration motor is arranged below the mixing barrel and is used to make the RFeB oil sludge waste in the mixing barrel vibrate. The material flows out from the discharge channel.

19. The method according to claim 18, characterized in that The oil sludge material mixed material filtering device further comprises: A spring, one end of which is connected to the bottom of the mixing barrel, and the other end of which is connected to a base, wherein the base is used to place the mixing barrel.

20. The method according to claim 19, characterized in that The oil sludge mixed material filtering device further includes a lifting component, and the lifting component is used to control the lifting of the base; The lifting assembly includes a traction rope, a pulley, a rotating shaft and a motor; the motor is fixed on the chassis, and the output shaft of the motor is connected to the rotating shaft for driving the rotating shaft to rotate; two pulleys are provided, and the two pulleys are respectively rotatably connected to the chassis; the traction rope is wrapped around the rotating shaft and one end of it is fixed to the rotating shaft, and the other end of the traction rope passes around the pulley and is fixed to the base.

21. The method according to claim 18, wherein The agitator includes a stirring shaft, a stirring disk and stirring teeth. The stirring disk is fixed at the lower end of the agitator, and the stirring teeth are fixed on the circumference of the stirring disk. The axial direction of the stirring shaft is parallel to the axial direction of the mixing barrel, and the upper end of the stirring shaft is connected to the drive motor.

22. The method according to any one of claims 1 to 6, characterized in that: The vacuum atmosphere rotary kiln comprises: Box; The furnace body is transversely arranged in the box body; the furnace body has an internal hollow cavity for placing RFeB type oily sludge waste; an air inlet chamber, connected to one end of the furnace body and having an axis of the air inlet chamber coincident with an axis of the furnace body; an exhaust chamber, connected to the other end of the furnace body and having an axis of the exhaust chamber coincident with an axis of the furnace body; A driving device, disposed in the box, for driving the furnace body to rotate; A pressure relief device and a vacuum gauge are provided above the furnace body. The pressure relief device is connected to the inside of the furnace body and is used to control the pressure inside the furnace body; the vacuum gauge is used to monitor the vacuum degree inside the furnace body.

23. The method according to claim 22, characterized in that The furnace body is further provided with a material lifting plate, which is a spiral structure and the axis of the material lifting plate coincides with the axis of the furnace body. Both ends of the material lifting plate are respectively fixed to the inner walls of both ends of the furnace body.

24. The method according to claim 22, characterized in that A lifting cylinder is also provided on the side wall of the box body, and the piston rod of the lifting cylinder is connected to one end of the air inlet chamber or the exhaust chamber, and is used to drive the furnace body to tilt so as to pour out the purified RFeB oil sludge waste in the furnace body.

25. An RFeB oil sludge powder, characterized in that: Prepared according to any one of claims 1 to 24.

26. Use of the RFeB oil sludge powder prepared according to the method according to any one of claims 1 to 24 in RFeB regenerative magnets.

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