JP2005243880A - Method for reusing sintered magnet sludge and magnet production system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reuse sludge produced through grinding effectively as a material for producing a magnet, and to produce magnets at low cost. <P>SOLUTION: The method for reusing sintered magnet sludge comprises a step for separating sludge, produced by grinding sintered magnet material from grinding fluid, and a step for drying the sludge separated from the grinding fluid within a predetermined time, and the dried sludge is employed as a material for producing a magnet. The sludge is preferably dried within 24 hours, after it has been produced. The method for reusing the sludge is applicable to R-TM-B based sintered magnet material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to magnet powder contained in grinding scrap generated when processing R-TM-B sintered magnets (R is one or more rare earth elements, TM is Fe, or Fe and Co). It relates to the method of reuse.

  Sintered magnet materials such as R-TM-B sintered magnets produced by powder metallurgy are usually commercialized through processing steps in order to obtain a desired shape. When grinding is performed during this processing, a grinding fluid is used. The grinding fluid is usually used by mixing water or water with a rust preventive agent for preventing oxidation of a magnetic material that is a workpiece or a workpiece for improving workability. After the processing is completed, sludge generated by grinding is discharged in a slurry state mixed with the grinding fluid.

  Since the amount of sludge produced by grinding can amount to several tens of percent of the product raw material, it is considered to reuse the sludge. Here, several methods have been proposed so far as sludge reuse methods. This method can be classified into (1) rare earth recovery method, (2) alloy regeneration method, and (3) magnet regeneration method.

  The rare earth recovery method is a method in which only rare earth elements are recovered from sludge as rare earth compounds and recycled to the raw material process. For example, Japanese Patent No. 2765470 (Patent Document 1), Japanese Patent Application Laid-Open No. 9-217132 (Patent Document 2), etc. Proposed. These methods have the advantage of being able to treat a large amount of sludge at a time and recovering high-purity rare earth compounds. Has been.

  The alloy regeneration method is a method in which sludge is recovered as an alloy having the same composition, and the sludge is melted by high-frequency melting, arc melting, plasma melting or the like to obtain a magnet alloy. For example, JP-A-8-31624 (Patent Document 3) and JP-A-6-136461 (Patent Document 4) have been proposed. By regenerating sludge as a magnet alloy, these methods can shorten the smelting process for obtaining an alloy containing rare earth and the melting process for obtaining the magnet alloy, and expensive transition metals other than the rare earth contained in the sludge. Also has the feature of being reusable. However, it has been pointed out that the recovery rate of rare earth elements is lowered and the crucible material is melted and mixed into the magnet alloy as foreign matter.

  On the other hand, the magnet regeneration method is a method of regenerating sludge as a magnet. For example, a method of obtaining a magnet by mixing sludge and rare earth-rich alloy powder at a predetermined ratio, molding and sintering (Japanese Patent No. 2746818). Publication (Patent Document 5)) has been proposed. In this method, sludge and a rare earth alloy are charged together in a crucible before melting by heating and melted in a high-frequency melting furnace to be regenerated as a magnet alloy. This method is economically advantageous because it can use the current magnet manufacturing apparatus and can also reuse expensive transition metals other than rare earth elements. Furthermore, in order to prevent melting damage of the crucible material, a rare earth alloy of about 10% by weight of the melting raw material is melted together, and further flux is added to reduce the amount of slag generation that causes the melting damage of the crucible material. It is characterized by doing. However, in this method, the yield in the case where no flux is added is very poor, so the amount of flux to be added needs to be about 40% of the melted raw material. Problems such as deterioration of magnetic characteristics and surface treatment characteristics, reduction of the rare earth recovery rate, and increase of processing costs have been pointed out.

  In contrast to the above, a method for remelting rare earth magnet sludge that can suppress flux scattering, suppress contamination in a melting furnace, and obtain a high purity magnet alloy using rare earth magnet sludge as a melting raw material is disclosed in Japanese Patent Application Laid-Open No. 2003-1999. No. -11429 (Patent Document 6). In this method, a raw material metal used for an R—Fe—B based magnet not containing a rare earth is charged in a crucible in advance, and after heating and melting, the raw material metal containing a rare earth element, an R—Fe—B based rare earth magnet sludge, and an alkali metal By adding an appropriate amount of a flux containing a halide of one or more metals selected from alkaline earth metals and rare earth metals, it is possible to recover the rare earth elements with high efficiency and improve the dissolution yield. That's it.

Japanese Patent No. 2765470 JP-A-9-217132 JP-A-8-31624 JP-A-6-136461 Japanese Patent No. 2774618 JP2003-113429A

The conventional sludge recycling method described above necessitates a treatment such as dissolving the sludge generated by grinding or converting it to another compound, and therefore the number of steps is inevitably increased. On the other hand, if there are few processes which process sludge, the value as a reuse method is large.
The present invention has been made based on such a technical problem, and an object thereof is to provide a method capable of effectively reusing sludge even with a small number of processing steps. Moreover, this invention aims at providing the method of obtaining a magnet using the magnet powder obtained by such a method. Furthermore, this invention makes it a subject to provide the manufacturing system for obtaining a magnet using the magnet powder obtained by such a method.

The conventional sludge recycling method has been to reuse a material obtained by subjecting the sludge to a treatment involving chemical or physical changes. The present inventors have studied a method of manufacturing a magnet using sludge as a raw material powder based on a novel idea that has been overlooked so far, in which the sludge itself is reused.
Usually, it is stored in a collection tank for a considerable time together with sludge and grinding fluid composed of particles of several μm to several tens of μm. Rare earth compounds such as R-TM-B sintered magnets are active, and particularly when the compound surface area is large, they easily react with oxygen. Sludge is composed of particles with a new surface exposed by processing, and its reaction with oxygen is fast, and even in a grinding fluid mixed with a rust inhibitor, oxidation of the powder proceeds as long as it is immersed for a long time. Magnetic properties are degraded.

Therefore, the present inventors measured the characteristics of the sludge and found that the characteristics sufficient for a magnet were obtained if the time immersed in the grinding fluid was within a predetermined time and then dried.
The present invention is based on the above knowledge, the step of separating the sludge generated by grinding the sintered magnet material from the grinding fluid, and the step of drying the sludge separated from the grinding fluid within a predetermined time And using a sludge that has been subjected to a drying treatment as a raw material for producing a magnet.
According to the present invention, since sludge generated by grinding is used as a raw material for magnet production, the sludge can be effectively reused and a magnet can be produced at low cost.

In the method for reusing sintered magnet sludge according to the present invention, it is desirable to perform a drying process 24 hours before the sludge is generated. This is because a decrease in the magnetic properties of the sludge, which is magnetic powder, can be minimized.
In the reuse method of sintered magnet sludge of the present invention, the sintered magnet material is an R-TM-B sintered magnet material (R is one or more rare earth elements, TM is Fe, or Fe and Co). ) Is desirable. This is because the R-TM-B based sintered magnet has high magnetic characteristics, and can have characteristics that sufficiently function as a magnet using the sludge.

  In the method for reusing sintered magnet sludge of the present invention, a sintered magnet or a bonded magnet can be produced using the sludge. When producing a sintered magnet, a step of forming a dried sludge into a predetermined shape and applying a magnetic field to produce a molded body, and a step of sintering the molded body to obtain a sintered magnet And comprising. Moreover, when manufacturing a bonded magnet, the step which mixes the sludge and drying material which were dried, and obtains a compound, and the step which shape | molds a compound in a predetermined shape are provided.

The present invention provides the following magnet manufacturing system capable of implementing the above-described method for reusing sintered magnet sludge. The magnet manufacturing system includes a processing unit that grinds a rare earth sintered magnet into a predetermined size and / or shape, a separation unit that separates sludge discharged from the processing unit from a grinding liquid, and sludge separated in the separation unit. And a magnet production unit for producing a magnet using the sludge dried in the drying unit.
In this magnet manufacturing system, as a magnet production unit, a sludge dried in the drying unit is molded into a predetermined shape in a magnetic field, and a molded body obtained in the magnetic field molding unit is sintered to sinter A sintered magnet can be manufactured.
In addition, the magnet production unit includes a compound production unit that produces a compound of the sludge dried in the drying unit and a binder, and a molding unit that molds the compound into a predetermined shape, thereby manufacturing a bonded magnet. Can do.

  As described above, according to the present invention, since sludge generated by grinding is used as a raw material for magnet production, the sludge can be effectively reused and a magnet can be produced at low cost.

Embodiments of the present invention will be described below.
The method for reusing sintered magnet sludge according to the present invention first separates sludge from a mixture of grinding fluid and sludge discharged by grinding the sintered magnet material. Usually, sludge generated during processing of the sintered magnet is discharged together with the grinding liquid into a recovery tank. The mixture discharged to the storage tank is separated into sludge and grinding liquid, for example, by filtration. Separation of the sludge and the grinding fluid can be performed collectively after a predetermined amount of the mixture is stored in the recovery tank, or can be continuously separated. Separation is not limited to filtration, and known solid-liquid separation means such as centrifugation can be widely applied.

The sintered magnet targeted by the present invention is not particularly limited. R-TM-B based sintered magnets (R is one or more rare earth elements, TM is Fe, or Fe and Co), R-Co It can be applied to a system sintered magnet.
In the present invention, R has a concept including Y, and one or more of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu and Y Selected from. Further, in order to improve the coercive force, one or more elements such as Al, Cr, Mn, Mg, Si, Cu, C, Nb, Sn, W, V, Zr, Ti, Mo, Bi, Ag and Ga are used. Two or more kinds may be contained.
The R—Co based sintered magnet contains R, one or more elements selected from Fe, Ni, Mn, and Cr, and Co. In this case, it preferably further contains one or more elements selected from Cu or Nb, Zr, Ta, Hf, Ti and V, and particularly preferably from Cu and Nb, Zr, Ta, Hf, Ti and V. Containing one or more selected elements. Among these, in particular, an intermetallic compound of Sm and Co, preferably an Sm ₂ Co ₁₇ intermetallic compound, is the main phase, and a subphase mainly composed of SmCo ₅ is present at the grain boundary.
Since the R-TM-B sintered magnet has high magnetic properties, a magnet having sufficient magnetic properties can be obtained depending on the application by applying the present invention. In addition, although R-TM-B system sintered magnet and R-Co system sintered magnet were mentioned here, this invention does not prevent application to other rare earth sintered magnets.

  In the present invention, known grinding fluids can be widely used. Only the water having the best cooling ability as the grinding liquid can be used as the grinding liquid, or an aqueous liquid containing an additive can also be used as the grinding liquid. In consideration of sludge reuse, it is desirable to use only water that can suppress sludge contamination as the grinding fluid. The present invention can be applied to any known grinding method such as surface grinding, double-edged grinding, vertical grinding, centerless grinding, and the like.

The sludge separated from the grinding fluid is still wet. Therefore, it is not left as it is, but is dried. By carrying out the drying treatment, it is possible to prevent an increase in the amount of oxygen and carbon from the grinding fluid. In the present invention, from the generation of sludge, in other words, it is recommended to dry the sludge within 24 hours after the sludge is immersed in the grinding fluid. This is because the deterioration of the magnetic properties of the sludge becomes significant after 24 hours. Any drying method is acceptable, but drying in an oxidizing atmosphere such as air should be avoided. This is because the amount of oxygen is increased. Therefore, it is desirable to perform the drying process in a non-oxidizing atmosphere, for example, in an Ar gas stream or in a vacuum.
The drying process is desirably performed at a temperature of 100 ° C. or lower. This is because if the drying process is performed at an excessively high temperature, the magnetic characteristics may be deteriorated. Therefore, the drying temperature may be selected in consideration of these matters. According to the study by the present inventors, a sufficient dry state can be obtained by holding for about 10 hours at room temperature, and a sufficient dry state can be obtained by holding for about 2 hours at 120 ° C.

  The sludge generated from the R-TM-B sintered magnet has the characteristics that the residual magnetization (σr) is 70 emu / g or more and the coercive force (Hcj) is 1170 Oe or more by drying within 24 hours from the generation. . Since the dried sludge has such characteristics, it can be used as a raw material for producing magnets. If the time from sludge generation to drying is shortened, a sludge having a remanent magnetization (σr) of 75 emu / g or more and a coercive force (Hcj) of 1200 Oe or more can be obtained.

  The sludge dried as described above can be used as a new raw material for producing a magnet because it has predetermined magnetic characteristics. The present invention can produce a sintered magnet using the dried sludge. Moreover, a bonded magnet can be manufactured using the dried sludge.

  When manufacturing a sintered magnet, sludge is shape | molded in a magnetic field, a molded object is produced, and this molded object is then sintered. Further, heat treatment such as aging heat treatment can be performed after sintering. That is, a normal process for manufacturing a sintered magnet can be applied. However, the sludge is a magnet particle having an average particle diameter of about 4 to 5 μm, although it depends on the grinding conditions, and thus the steps such as preparation of the raw material alloy and pulverization can be omitted. Thus, the present invention has an advantage that a sintered magnet can be manufactured at a very low cost.

The sludge according to the present invention can also be used as magnet powder for producing a bonded magnet. When manufacturing a bonded magnet, first, a compound comprising sludge and a binding material for binding the sludge is prepared. As the binder, a thermosetting resin, a thermoplastic resin, or rubber (elastomer) can be used. As the molding of the compound, compression molding, injection molding, extrusion molding or rolling can be used. In general, when a thermosetting resin is used, the compound is compression molded at room temperature. In addition, when a thermoplastic resin is used, there are many examples of injection or extrusion molding under heating.
Further, a magnetic field may or may not be applied when molding. An anisotropic bonded magnet is obtained when a magnetic field is applied, and an isotropic bonded magnet is obtained when no magnetic field is applied.

  The dried sludge can be used for new magnet production as it is. Although it was dried, it is also assumed that contaminants are attached to the surface because it was immersed in the grinding fluid. Therefore, sludge can also be used for new magnet manufacture after washing and degreasing. Also, sludge usually has a preferred particle size for new magnet production, but if not, particle size adjustments such as grinding can be made to obtain the required particle size.

Next, a preferred system for carrying out the method for reusing sintered magnet sludge according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a magnet manufacturing system. The magnet manufacturing system 10 can manufacture a sintered magnet using a new raw material alloy obtained by strip casting or other casting methods. Further, the magnet manufacturing system 10 uses a new raw material alloy to manufacture a sintered magnet (first magnet), in particular, a sintered magnet (second magnet) using sludge produced by grinding as a raw material powder. ) Can be manufactured.

The magnet manufacturing system 10 includes a crushing unit 1. The pulverizing part 1 is a part for pulverizing the raw material alloy to a predetermined particle size. The pulverization in the pulverization unit 1 can be divided into two stages: coarse pulverization and fine pulverization. Coarse pulverization can be performed by hydrogenation pulverization or a coarse pulverizer. In the hydrogenation pulverization, the raw material alloy is exposed to a hydrogen-containing atmosphere at room temperature to absorb hydrogen. After the hydrogen storage is completed, a dehydrogenation process is performed in which the raw material alloy that has been subjected to hydrogen storage is heated and held. This treatment is performed for the purpose of reducing hydrogen as an impurity as a permanent magnet.
The coarse pulverization can also be performed in an inert gas atmosphere using a pulverizer such as a stamp mill, a jaw crusher, or a brown mill.
After coarse pulverization, move to fine pulverization. In the fine pulverization, the average particle size is usually processed to about 1 to 10 μm using an airflow pulverizer. When finely grinding a fatty acid or a derivative of a fatty acid for the purpose of improving lubrication and orientation during molding, for example, stearic acid-based or oleic acid-based zinc stearate, calcium stearate, stearic acid amide, oleic acid amide, etc. Can be added.

The magnet manufacturing system 10 includes a magnetic field forming unit 2. The magnetic field forming unit 2 forms the fine powder obtained in the pulverizing unit 1 into a predetermined shape while applying a predetermined magnetic field. What is necessary is just to make the shaping | molding pressure in shaping | molding in a magnetic field into the range of 0.5-5 ton / cm < ² >. The molding pressure may be constant from the beginning to the end of molding, may be gradually increased or gradually decreased, and may be irregularly changed. The lower the molding pressure is, the better the orientation is. However, if the molding pressure is too low, the strength of the molded body is insufficient and handling problems occur. Therefore, the molding pressure is selected from the above range in consideration of this point. The final relative density of the molded body obtained by molding in a magnetic field is usually 50 to 60%. The strength of the magnetic field to be applied may be appropriately selected from the range of 5 to 30 kOe. The magnetic field to be applied is not limited to a static magnetic field but can be a pulsed magnetic field. In that case, it is preferable to apply a magnetic field of 1 T (absolute value) or more for 10 μs to 0.5 s.
For forming in the magnetic field, both a so-called transverse magnetic field forming method in which the pressurizing direction and the magnetic field applying direction are substantially orthogonal, and a so-called vertical magnetic field forming method in which the pressurizing direction and the magnetic field applying direction substantially coincide can be used.

  The molded body obtained by molding in a magnetic field is sintered in a vacuum or a non-oxidizing gas atmosphere in the sintering part 3. Sintering conditions need to be adjusted according to various conditions such as composition, pulverization method, difference in average particle size and particle size distribution, but may be sintered at 900 to 1200 ° C. for about 1 to 10 hours.

  The sintered body obtained by the sintering is then subjected to heat treatment in the heat treatment section 4. By this heat treatment, the coercive force of the rare earth sintered magnet can be improved. As this heat treatment, it is held at a temperature of 350 ° C. or higher and lower than the sintering temperature for a predetermined time. In the case of an R-TM-B sintered magnet, it is effective to perform this heat treatment in two stages.

The sintered body (sintered magnet) subjected to the heat treatment is subjected to various processing in the processing section 5 in order to obtain a predetermined shape and size. The processed sintered body forms a product or a product after surface treatment for imparting corrosion resistance is performed. Here, the processing includes various things such as cutting, grinding, lapping, and chamfering, and the present invention aims to reuse sludge generated by grinding.
The magnet manufacturing system 10 includes a separation unit 6 that separates sludge generated by grinding from grinding fluid. In the present invention, the specific means for separating the grinding fluid and sludge in the separation section 6 is not limited. For example, after a mixture of sludge and grinding fluid is stored in a recovery tank for a predetermined time, the mixture can be separated into grinding fluid and sludge by passing the mixture through a filtering means. Alternatively, the generated sludge may be separated by continuously passing through a filtering means.
As the means for separating the grinding liquid and the sludge in the separation unit 6, known means such as filtration means such as filter paper and a centrifugal separator can be used. In addition, it may be a means for separating the grinding liquid and sludge by magnetic force. In addition, although sludge is isolate | separated from a grinding fluid in the isolation | separation part 6, normally it does not need to be dried. Therefore, the sludge is dried in the drying unit 7.

  The magnet manufacturing system 10 includes a drying unit 7. The drying unit 7 dries the sludge separated from the grinding fluid in the separation unit 6. The drying environment in the drying unit 7 does not matter. However, since there is a risk of promoting the oxidation of sludge in an environment containing a large amount of oxygen, it is preferable to dry with equipment having an area that can realize a vacuum or a non-oxidizing atmosphere. Further, the drying temperature is as described above, and the drying unit 7 may include a heating unit.

  The magnet manufacturing system 10 includes a storage unit 8 that temporarily stores the dried sludge. The storage unit 8 stores the sludge until an amount of sludge sufficient for forming by the forming unit 2 in the magnetic field is accumulated. As the storage unit 8, a container or the like that can avoid contact with outside air can be used. When a predetermined amount of sludge is accumulated, the magnetic field forming unit 2 forms sludge as magnet powder in the magnetic field. The compact obtained by molding in a magnetic field is subjected to sintering in the sintering part 3. In the present invention, sludge can be directly supplied from the drying unit 7 to the magnetic field forming unit 2 without providing the storage unit 8 as in the magnet manufacturing system 20 shown in FIG.

  In the magnet manufacturing system 10, a series of processing from the processing unit 5 to the storage unit 8 can be performed batchwise, but can also be performed continuously. For example, by providing a conveyance path for continuously conveying sludge between the processing unit 5 and the separation unit 6, the separation unit 6 continuously separates the sludge from the grinding fluid. Furthermore, by providing a transport path for transporting sludge between the separation unit 6 and the drying unit 7, the sludge is continuously supplied to the drying unit 7. The drying unit 7 performs the drying process on the supplied sludge, but the drying process can be completed in the order of the supply. Therefore, by providing a conveyance path for continuously conveying sludge between the drying unit 7 and the storage unit 8, the dried sludge can be continuously supplied to the storage unit 8. As described above, a sintered magnet can be efficiently obtained using sludge.

The magnet manufacturing systems 10 and 20 described above use a sludge to manufacture sintered magnets in which the forming part 2, the sintering part 3, the heat treatment part 4, and the processing part 5 in the magnetic field are performed using a new raw material alloy. It is common to manufacture sintered magnets. However, as in the magnet manufacturing system 30 shown in FIG. 3, the magnetic field forming part 21, the sintered part 31, the heat treatment part 41, and the processing part 51 can be separately provided exclusively for the production of sintered magnets using sludge. .
The magnet manufacturing systems 10, 20 and 30 use sludge as a raw material for sintered magnets. However, as in the magnet manufacturing system 40 shown in FIG. 4, a compound of sludge and resin as a binder is used. It is also possible to provide a compound production part 91 to be produced and an injection molding part 92 for producing a bonded magnet by, for example, injection molding the compound produced by the compound production part 91.

An alloy composed of 31 wt% Nd-0.2 wt% Al-0.5 wt% Co-0.07 wt% Cu-1.0 wt% B-balance Fe was produced by a strip cast method. The obtained strip-cast alloy was occluded with hydrogen at room temperature and then subjected to hydrogen occlusion / dehydrogenation treatment for dehydrogenation at a temperature of 500 ° C.
Thereafter, coarse pulverization by a stamp mill and fine pulverization by a jet mill were performed to obtain a fine powder having an average particle diameter of 4.0 μm. When finely pulverizing with a jet mill, 0.1 wt% of oleic acid amide was added.

Next, this fine powder was molded in a magnetic field at a pressure of 1.5 t / cm ² while applying a magnetic field of 15 kOe. The obtained molded body was sintered by holding at 1050 ° C. for 4 hours. Next, the obtained sintered body was subjected to a two-stage aging treatment of 800 ° C. × 1 hour and 530 ° C. × 2.5 hours (both in an Ar atmosphere).
As for the magnetic properties of the Nd—Fe—B sintered magnet obtained as described above, the residual magnetic flux density (Br) was 13.5 kG, and the coercive force (Hcj) was 16.5 kOe.

In order to make the above Nd—Fe—B based sintered magnet into a desired size, it was processed using a vertical grinding machine. The grinding liquid used was water added with a triethanolamine solution as a rust inhibitor.
Processing to a desired size was performed for about 2 hours, and sludge generated during the processing was stored in a collection tank. Sludge was immersed in the grinding fluid and stored in the collection tank, and after a predetermined time had elapsed from the end of processing, it was taken out from the collection tank together with the grinding fluid. The taken-out sludge was filtered using a filter paper to separate the grinding fluid and the sludge. Furthermore, the sludge was transferred to a metal bat and vacuumed at 120 ° C. for 2 hours in a vacuum thermostatic chamber, and a drying process was performed to evaporate the remaining water.

  The dried sludge was measured with a VSM (vibrating sample magnetometer, applied magnetic field 1.9T), and the magnetic properties were evaluated. Moreover, the oxygen amount and carbon amount of sludge were measured. The results are shown in Table 1.

  As shown in Table 1, sludge dried for 48 hours from the end of grinding can be used as magnetic powder with a small decrease in magnetic properties. It can be seen that sludge dried for 24 hours from the end of grinding shows almost no decrease in magnetic properties as compared to immediately after grinding.

It is a block diagram which shows the structure of the magnet manufacturing system in this Embodiment. It is a block diagram which shows the other structure of the magnet manufacturing system in this Embodiment. It is a block diagram which shows the other structure of the magnet manufacturing system in this Embodiment. It is a block diagram which shows the other structure of the magnet manufacturing system in this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Grinding part, 2, 21 ... Molding part in magnetic field, 3,31 ... Sintering part, 4,41 ... Heat treatment part, 5,51 ... Processing part, 6 ... Separation part, 7 ... Drying part, 8 ... Storage part 91 ... Compound production section, 92 ... Injection molding section, 10, 20, 30, 40 ... Magnet manufacturing system

Claims (8)

Separating the sludge generated by grinding the sintered magnet material from the grinding fluid;
Drying the sludge separated from the grinding fluid within a predetermined time, and
A method for reusing sintered magnet sludge, characterized in that the dried sludge is used as a raw material for magnet production.   The method for reusing sintered magnet sludge according to claim 1, wherein the sludge is dried before 24 hours from the generation.   The sintered magnet material is an R-TM-B sintered magnet material (R is one or more rare earth elements, TM is Fe, or Fe and Co). 2. A method for reusing sintered magnet sludge according to 2. Molding the sludge that has been dried into a predetermined shape, and applying a magnetic field to produce a molded body;
The method for reusing sintered magnet sludge according to any one of claims 1 to 3, further comprising a step of obtaining a sintered magnet by sintering the compact. Mixing the dried sludge and binder to obtain a compound;
The method for reusing sintered magnet sludge according to any one of claims 1 to 3, further comprising: forming the compound into a predetermined shape. A processing portion for grinding a rare earth sintered magnet to a predetermined size and / or shape;
A separation unit for separating the grinding fluid and sludge discharged from the processing unit into the grinding fluid and sludge;
A drying unit for drying the sludge separated in the separation unit;
A magnet production unit for producing a magnet using the sludge dried in the drying unit;
A magnet manufacturing system comprising: The magnet production part is
A magnetic field molding part for molding the sludge dried in the drying part into a predetermined shape in a magnetic field;
The magnet manufacturing system according to claim 6, further comprising: a sintered part that sinters the molded body obtained by the molded part in the magnetic field. The magnet production part is
A compound preparation section for preparing a compound of the sludge and the binder dried in the drying section;
The magnet manufacturing system according to claim 6, further comprising: a molding unit that molds the compound into a predetermined shape.

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