JP2000160211A - METHOD FOR REGENERATING Sm-Fe-N BASE ALLOY POWDER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently regenerating the scrap of a bond magnet contg. Sm-Fe-N base alloy powder. SOLUTION: Scrap of a compsn. for a bond magnet is baked in the temp. range of 600 to 1,500 deg.C in the presence of oxygen, is mixed with a new raw material mixture required for producing new alloy powder and is mixed with metal Ca or Ca hydride by the amt. 1.1 to 2.0 times the theoretical one needed for reducing Sm oxide in this mixture to a metal state, and reduction diffusing treatment in which it is heated in the temp. range of 900 to 1,200 deg.C is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a high-quality Sm-Fe-N alloy powder from a bonded magnet scrap contained in a resin powder of the Sm-Fe-N alloy powder.

[0002]

2. Description of the Related Art Rare earth magnets are known as high performance magnets,
Despite its short history, its market size has come close to ferrite. Further, the use of the rare earth magnet as a bonded magnet formed by incorporating the magnetic powder in a resin is rapidly expanding, and the amount of the rare earth magnet used is almost equal to that of the sintered magnet.

[0003] In the development of rare-earth magnets, improvement of magnetic properties has been a central issue, and its economic aspects have been relatively neglected. However, it will be gradually examined in connection with recent approaches to global environmental issues. It has become
In particular, there is a need for a method for efficiently collecting high-quality magnetic powder from scraps that come out of the rare earth bonded magnet manufacturing process or scraps that are assembled into motors and sold on the market and then collected as waste. Have been.

Japanese Patent Publication No. Sho 61-153201 discloses a method of heating a rare earth magnet scrap in a wet hydrogen atmosphere. In this method, the resin is removed under conditions such that only the resin is selectively burned and the alloy powder is not oxidized. However, such control is not so easy in practice. In particular, the Sm-Fe-N-based alloy powder has N in the crystal, which is heated at a low temperature of about 600 ° C. in an inert gas. However, there arises a problem that N is desorbed from the crystal and the magnetic properties are degraded. Therefore, the method of JP-B-61-153201 cannot be applied to the regeneration of Sm-Fe-N-based alloy powder.

[0005]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for efficiently and efficiently regenerating a scrap of a bonded magnet containing an Sm-Fe-N alloy powder as described above. I do. Further, the present invention provides a method for regenerating an Sm-Fe-N-based alloy powder capable of reducing the amount of expensive Sm used.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the scrap of the bonded magnet was burned in a specific temperature range in the atmosphere to burn the resin components, and the resin was burned. At the same time, they have found that the problem is solved by simultaneously oxidizing Sm and Fe, mixing them with new raw materials and performing reduction diffusion.

That is, the method for regenerating the Sm-Fe-N-based alloy powder of the present invention uses a bonded magnet composed of an Sm-Fe-N-based alloy powder and a resin or a scrap of a bonded magnet composition such as a compound used for the same. , Sm-Fe
A method for regenerating an -N-based alloy powder is characterized in that the following steps are provided in this order. (A) firing the scrap of the bonded magnet composition in a temperature range of 600 to 1500 ° C. in the presence of oxygen; (B) The obtained fired product is pulverized to have an average particle size of 1 μm to 10 μm, and if necessary, reduced in a reducing gas atmosphere of hydrogen or hydrocarbon at a temperature range of 300 to 900 ° C. (C) Sm required to produce a new alloy powder
The stoichiometric amount required to mix a new raw material mixture obtained by mixing the raw material components and the Fe raw material components in a predetermined ratio with the processed product obtained in the step (b), and to reduce the Sm oxide in the mixture to a metallic state. Is reduced and diffused by mixing metal Ca or hydrogenated Ca 1.1 to 2.0 times of the above and heating in a temperature range of 900 to 1200 ° C. (D) The product obtained by the reduction diffusion treatment is placed in a gas atmosphere of nitrogen or a compound containing nitrogen in a gas atmosphere of 300 to 700.
A nitriding treatment is performed by heating in a temperature range of ° C. (E) The treated product obtained in the step (d) is put in water to disintegrate, and washed with water and acid. However, nitriding may be performed after the reduction diffusion treatment.

In the method for regenerating an Sm—Fe—N alloy powder according to the present invention, in the step (c), the mixture to be subjected to the reduction diffusion treatment has an r value in a range of 10.6 to 12.4. It is preferable to adjust as follows. Here, the r value is defined by the following equation, and ASm and AFe are the numbers of atoms of Sm and Fe in the raw material oxide, respectively. r = ASm / (ASm + AFe) × 100

In the method for regenerating an Sm-Fe-N-based alloy powder according to the present invention, in the step (c), the treated material obtained in the step (b) may be added up to 400 parts by weight with respect to 100 parts by weight of the new raw material mixture. Partial mixing is preferred. Here, the new raw material mixture is a raw material mixture obtained by mixing Sm and Fe at a predetermined ratio, which is necessary for producing a new alloy powder.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A typical example of a material applicable to the Sm-Fe-N alloy powder of the present invention is Sm2F.
There is e17N3 alloy powder. This alloy powder exhibits a coercive force development mechanism called nucleation, and has the feature that the reduction in the size and uniformity of crystal grains directly leads to the magnitude of the coercive force.

The object of reproduction of the present invention is this Sm
-It is a scrap of a bonded magnet (including a compound) molded with a resin binder using Fe-N-based alloy powder as a filler. Scraps include those that come out of the manufacturing process or are recovered from the market, and cover all those that have failed due to physical deformation, chemical corrosion or oxidation.

In general, a compression molding method, an injection molding method, and an extrusion molding method are generally applied to a method of molding a bonded magnet. The compression molding method is a method in which the compound is filled in a press die, and the molded product is compression-molded to obtain a molded body, and then heated to cure a thermosetting resin as a binding resin to produce a magnet. is there. The amount of resin binder in the magnet is as small as 10 vol% or less. As a thermosetting resin used in the compression molding method, there is a typical epoxy resin, and in addition, bakelite, urea resin, melamine resin and the like are used. In the extrusion molding method, the heated and melted compound is extruded from the mold of the extrusion molding machine and solidified by cooling,
This is a method of cutting into a desired length to form a magnet. The addition amount of the binder resin is about 20 vol%, which is larger than that of the compression molding method. The injection molding method is a method in which the compound is heated and melted, the molten material is injected into a mold in a state where sufficient fluidity is provided, and the compound is molded into a predetermined magnet shape. The addition amount of the resin binder is about 40 vol%, which is even larger than the extrusion molding method. Engineering resins such as polystyrene, polyamide, polycarbonate, and polyester are used as resin binders for injection and extrusion molding, and super-engineering resins such as polyphenylene sulfide (PPS) and liquid crystal polymers are used. The present invention relates to the use of 6
Since the resin is fired in a temperature range of 00 to 1500 ° C., all of these resins are burned and disappeared.

In the present invention, in order to burn the resin efficiently, it is preferable that the bonded magnet scrap is first roughly crushed into a few mm square. If the combustion is too large, the resin will take extra time to completely burn,
Time and fuel are wasted. For this coarse pulverization, for example, a jaw crusher, an impeller breaker, a hammer mill or the like can be used.

Normally, a resin can be burned in the atmosphere at a temperature of about 400 ° C., but in the present invention, burning the resin at a high temperature of 600 to 1500 ° C. in the atmosphere is intended for the purpose of burning the resin. In addition to the above, the purpose is to oxidize the metal of Fe and Sm, and to subsequently form a double oxide of Sm and Fe. Therefore, the resin is not necessarily required, and the operation and effects described below are not limited to the bonded magnet.
It is also applicable to the regeneration of the Sm-Fe-N-based alloy powder itself.

As a double oxide of Fe and Sm, SmFeO
3, Sm3Fe5O12, Sm2FeO4, etc., which are generated by heating at a temperature of 600 ° C. or more in the atmosphere. In particular, a mixture of Sm2O3 and Fe2O3
When heated at a relatively low temperature of about 0 to 1100 ° C, Sm
FeO3 is easily produced, and when the temperature is higher than that, a mixed oxide of Sm3Fe5O12 comes to be mixed therein.
When the temperature exceeds 400 ° C., the peak of SmFeO 3 almost disappears, and Sm 3 Fe 5 O 12 becomes the main component. This double oxide is not produced unless oxygen is present. Therefore, 60
The oxide of Fe and the oxide of Sm generated by firing at a high temperature of 0 ° C. or more further react to form a double oxide.

The treated product obtained by firing the bonded magnet under the above-mentioned conditions is a mixture containing Fe2O3 at the same time as the double oxide. This mixture is pulverized to an average particle size in the range of 1 μm to 10 μm. In a reducing gas atmosphere in a temperature range of 300 to 900 ° C. Oxygen contained in Fe2O3 can be removed by this reduction. However, the oxygen of the double oxide remains without being reduced.

Here, the necessary case means that, in the reduction diffusion in the next step, the treated product (total amount of oxides to be regenerated (mainly double oxides, Fe 2 O 3)) obtained in the step (b) with respect to the new raw material mixture is used. In many cases. In particular,
When the total amount of oxides to be regenerated is more than 29 parts by weight per 100 parts by weight of the new raw material mixture, in this case, Fe
The amount of 2O3 present becomes too large, and the reduction reaction by Ca explosively occurs, causing not only the particles to be coarsened due to heat generation, but also, in the worst case, the product to scatter in the furnace due to the explosive reaction. .

When the reduction treatment is performed with a reducing gas such as hydrogen or hydrocarbon before the reduction diffusion step, the processed material obtained in the step (b) is reduced to 400 parts by weight with respect to 100 parts by weight of the new raw material mixture. Can be mixed. 400
If the mixing is performed in excess of parts by weight, the ratio of recycled material that is unsafe in terms of stability of particle size distribution and contamination of foreign substances increases compared to new breed material, causing abnormal particle growth during the reduction diffusion process, As a result, satisfactory magnetic properties are not exhibited. However, conversely, by mixing the processed material which has not been subjected to the reduction treatment with a new raw material mixture in an amount of about 29 parts by weight or less in the reduction diffusion step, the reaction in the reduction diffusion step is promoted by self-heating due to the combustion of Fe2O3.

In the reduction diffusion step, Ca or hydrogenation uses 1.1 to 2.0 times the theoretical amount required to reduce Sm 2 O 3 and oxygen of the double oxide. When the amount is less than this range, sufficient reduction is not performed. On the other hand, when the amount is more than this range, the amount becomes excessive, and a large amount of unreacted Ca metal unrelated to the reaction remains. As a result, in the disintegration reaction to water in the subsequent step, if a large amount of excess Ca remains, a large rapid exothermic reaction occurs, deteriorating the performance of the magnetic powder.

The reduction diffusion reaction is carried out in an inert atmosphere such as Ar or He at a temperature of 900 to 1200 ° C. The reason is that although reduction diffusion occurs even at a temperature lower than this temperature range, the reaction is extremely slow and is not very practical.If the reaction temperature is higher than this temperature range, the reduction diffusion reaction occurs rapidly and becomes difficult to control. Because.

While the product obtained by the reduction diffusion step is kept in the same reactor as it is, the temperature is lowered, and the atmosphere gas is changed from an inert atmosphere such as Ar or He to a gas containing nitrogen such as N2 or NH3. Switch to 300-7
By heating in a temperature range of 00 ° C., the product obtained in the reduction diffusion step can be subjected to a nitriding treatment. If the temperature is lower than this temperature range, the reaction speed is too slow to be practical. If the temperature is higher than this range, the nitridation reaction proceeds, but the resulting crystal becomes amorphous, so that an alloy powder having good magnetic properties cannot be obtained.

In order to pulverize the porous Sm-Fe-N alloy block obtained in the nitriding step, when the reaction product is put into ion-exchanged water, the alloy block immediately collapses. At this time, unreacted Ca compounds such as CaO and CaN in the reaction product or the remaining Ca metal react with water to generate fine Ca (OH) 2 and float. If the suspended matter is removed by decantation or the like, and further subjected to an acid treatment, complete removal can be performed.

Here, the method of performing the nitriding treatment after the reduction diffusion reaction has been described. The nitridation reaction is performed after the alloy block obtained in the reduction diffusion step is poured into water, collapsed, washed, and powdered. May be.

In the method for regenerating an Sm-Fe-N-based alloy powder according to the present invention, the raw material mixture to be subjected to the reduction diffusion treatment in the step (c) has an r value in the range of 10.6 to 12.4. It is preferable to prepare as follows. Here, the r value is defined by the following equation, and ASm and AFe are the numbers of atoms of Sm and Fe in the raw material oxide, respectively. r = ASm / (ASm
+ AFe) × 100

FIG. 1 shows the relationship between the raw material charging ratio r = ASm / (ASm + AFe) × 100 of the Sm2Fe17N3 ferromagnetic material and the true coercive force iHc. The two curves (a) and (b) in the figure are plotted based on a large number of data for the product of the present invention and the comparative product, respectively. The term "product of the present invention" used herein refers to a material obtained by subjecting a scrap of a bonded magnet to the above-described regeneration treatment in a raw material to be subjected to reduction diffusion.

FIG. 2 shows the relationship between the raw material charging ratio r = ASm / (ASm + AFe) × 100 of the Sm2Fe17N3 ferromagnetic material and the residual magnetization Br. The two curves (a) and (b) in the figure are plotted based on a large number of data for the product of the present invention and the comparative product, respectively.

The hydrogen-reduced product is 100 parts by weight with respect to the new raw material mixture, and a specific production method thereof will be described later as Examples 2 and 3. On the other hand, the comparative product is a case where the hydrogen reduced product which has been subjected to the scrap treatment of the bonded magnet as described above is not mixed with the new raw material mixture, and will be described later as Comparative Example 1.

Since the true coercive force of the Sm2Fe17N3 ferromagnetic material strongly depends on its particle diameter, the average particle diameter of both the product of the present invention and the comparative product is adjusted to 3 μm. 1 and 2, the value of r was 1 for both the product of the present invention and the comparative product.
The coercive force and the remanent magnetization are improved with increasing from 0.5. This corresponds to the Sm ratio in the metal element of the Sm2Fe17N3 ferromagnetic material being 10.53% in stoichiometric ratio. (R = 2 / (2 + 17) × 100 = 1
In either case, the charging ratio of Sm needs to be larger than the stoichiometric ratio. This is mainly due to evaporation and oxidation of the metal Sm.

1 and 2, the r value of the comparative product was 12.5.
, The coercive force and the remanent magnetization are maximized, whereas in the case of the present invention, the maximum is reached at 11.5, and the coercive force and the remanent magnetization are both larger than the maximum of the comparative product. That is,
The present invention shows that high characteristics can be obtained while reducing relatively expensive Sm. By applying the method of the present invention using a composite oxide as a raw material for reduction diffusion, the reactivity of reduction diffusion can be improved, and the reduction diffusion temperature can be lowered. As a result, it is possible to reduce the Sm charging ratio having a higher vapor pressure than iron.

The melting point of metal Ca is 842 ° C.
The melting point of metal Sm is 1074 ° C. Therefore, it seems that the reduction diffusion reaction is sufficient if the temperature is 1100 ° C. or higher. However, in actuality, in consideration of volatilization of Sm for improving the reactivity, the reduction diffusion reaction is conventionally performed in the range of 1100 to 1200 ° C. Was. In contrast, the present invention includes a step of heating scrap such as a bonded magnet in the atmosphere at a temperature in the range of 600 to 1500 ° C., and a double oxide is generated in this step. Since the mixed oxide is mixed with the raw material, the reactivity of reduction diffusion is improved, and as a result, the reduction diffusion reaction is completed in a temperature range of 900 to 1200 ° C.

In the present invention, when the amount of the double oxide in the raw material mixture is 1 wt% or more, preferably 5 wt% or more, the reactivity is improved in the reduction diffusion step. For the quantitative determination of multiple oxides, X-ray diffraction of a raw material obtained by mixing known amounts of multiple oxides is measured, and a calibration curve is created from the peak height characteristic of the multiple oxides and the mixed concentration of the multiple oxides. I went by that.

The reason why the presence of such a small amount of double oxide enhances the reactivity of the reduction diffusion reaction is estimated as follows. The reduction diffusion reaction is a reaction in which a rare earth metal and a transition metal reduced to a metal by a reducing agent generally diffuse into each other in a solid phase to form an alloy. The diffusion takes time because the reaction is between solid phases, but if it is too long, the particle growth proceeds and becomes larger than the desired particle diameter, so the reaction time is limited to a short time, and as a result, the diffusion is not sufficient Parts are formed and the composition of the alloy becomes non-uniform. On the other hand, the multiple oxides have already diffused into each other when they are reduced, and an alloy can be formed immediately. Furthermore, since the remaining rare earth metals and transition metals also diffuse into the alloy derived from the double oxide, it is more advantageous than the diffusion between the simple substances,
As a result, diffusion and alloying are completed in a short time, and alloy particles having a small diameter and a uniform composition can be obtained.

The treatment of the bonded magnet scrap mixed with the new raw material mixture has been described in detail. In the present invention, the following preferred embodiments are also used for the Fe and Sm raw materials used for the new raw material mixture.

The new Fe raw material has an average particle size of 0.5 to
Fine particle Fe metal in the range of 2.0 μm can be preferably used. Alternatively, by reducing Fe oxides of fine particles such as FeO, Fe3O4, and Fe2O3 with a reducing gas or the like, fine metal particles having a sharp particle size distribution can be obtained. Since the obtained alloy powder inherits the particle shape and size of the Fe powder, the Fe raw material is very important for obtaining an alloy powder having a good particle shape and particle size distribution.

In order to obtain a new raw material mixture having better particle characteristics, Sm and Fe are dissolved in an acid, and a substance which forms an insoluble salt with Sm and Fe ions is reacted in a solution to control various conditions. Precipitate particles with excellent particle properties,
The obtained precipitate is calcined to form a metal oxide, and further reduced to obtain a raw material mixture having excellent particle characteristics to be subjected to a reduction diffusion step. In particular, since the Sm2Fe17N3 alloy powder has a nucleation-type coercive force development mechanism, the particle characteristics (particle size, particle size distribution) of the alloy powder are particularly important.

Each of the above-mentioned raw material mixtures must have an average particle diameter of 10 μm or less. Preferably it is 5 μm or less, and more preferably the average particle size is in the range of 0.2 μm to 2 μm.

As described above, in the present invention, by firing the scrap of the composition for a bonded magnet in the temperature range of 600 to 1500 ° C. in the air, a double oxide of Sm and Fe is generated, and as a result, reduction diffusion Since the reaction can be promoted at a lower temperature and there is no need to correct the raw material before the reduction diffusion step, the raw material obtained by heating can be directly used in the reduction diffusion step. Further, in order to obtain these composite oxides, it is necessary to heat Sm2O3 and Fe2O3 at a high temperature as described above. The reaction to obtain a composite oxide from these two kinds of oxides is performed in an oxidizing atmosphere, Since Sm metal is not released, there is no problem of volatilization of Sm.

The Sm2Fe17N3 obtained according to the present invention is
Since it is not subjected to a pulverizing action by a mechanical impact force, it has an advantage in characteristics as compared with the same powder obtained by a conventional pulverizing method. The pulverization method by mechanical impact here is a method generally employed in the powder metallurgy industry, and includes a jaw crusher, a stamp mill, a roll crusher, a hammer mill, a pin mill, a ball mill, a vibration mill, an attritor, a sand mill, and a jet. It refers to, but is not limited to, a mill, a homogenizer, and the like.

[0039]

[Example 1] 60% by weight of Sm2Fe17N3 based alloy powder (average particle size by Fisher sub sieve sizer: 2.5 μm) and 40% by weight of nylon
Was ground to 3 mm square using a hammer mill. Next, the pulverized product was placed in an alumina crucible and calcined at 850 ° C. for 5 hours in the atmosphere to completely remove the resin.

The obtained fired product was ground to a mean particle size of 2.0 μm by using a jet mill using the atmosphere. The pulverized product was subjected to an X-ray diffraction measurement using Cu-Kα as a source. As a result, it was found that a peak at 2θ was 35.6 ° and α-Fe2O3 was obtained.
But 22.8%, 31.9%, 32.7%, 33.1%
{, 46.7}, and 58.9} peaks indicate that SmFeO
It was confirmed that three double oxides were formed.

When the pulverized product was reduced by heat treatment at 700 ° C. for 3 hours in a hydrogen atmosphere, α-Fe 2 O 3 having a peak at 2θ = 35.6 ° disappeared, and instead 2θ = 44. A mixture of the peak at 7 ° and the double oxide was obtained. As a result of chemical analysis of the obtained reduced product, Sm was 17.6.
% By weight and Fe was 55.7% by weight.

On the other hand, in order to obtain a new Sm 2 Fe 17 N 3 alloy powder, Sm having an average particle size of 0.3 μm was used as a raw material.
698 g of 2O3 powder and 1731 g of carbonyl iron having an average particle diameter of 5.3 μm were mixed in a dry ball mill in a nitrogen atmosphere for 3 hours.

200 g of a reduced product obtained from the treatment of the bonded magnet scrap was mixed with 1000 g of a new raw material by a ball mill. In this state, the r value is 11.4. To this mixture, 748.9 g of granular metallic calcium having a diameter of 10 mm or less was further mixed, and the mixture was placed in a steel container and placed in a gas atmosphere furnace under an argon gas atmosphere under 1150 g.
The mixture was heated at a temperature of 1 ° C. for 1 hour to perform reduction diffusion, and then cooled. 450 ° C while continuously flowing nitrogen gas into the same furnace
For 20 hours, and then cooled. The obtained reactant is put into ion-exchanged water to disintegrate,
(OH) 2 was removed by decantation and acid washed. Next, the washed slurry was filtered and the solid content was dried to obtain an Sm2Fe17N3 alloy powder.

The obtained alloy powder exhibited the following magnetic properties. iHc 11.8 kOe Br 12.0 kG BHmax 31.5 MGOe However, the average particle size of the alloy powder is 2.8 μm.

Here, the magnetic characteristics were measured as follows. The magnetic characteristics of the Sm2Fe17N3 alloy powder are measured by a VSM (vibrating sample magnetometer) having a maximum magnetic field of 20 kOe. At this time, the alloy powder is packed in a sample case together with paraffin wax, the paraffin wax is melted by a drier, the axes of easy magnetization are aligned with an orientation magnetic field of 20 kOe, and pulse magnetization is performed with a magnetization magnetic field of 40 kOe. Also Sm
The true density of the 2Fe17N3 intermetallic compound was 7.66 g / ml and evaluated without demagnetizing field correction.

Example 2 As a raw material for obtaining a new Sm 2 Fe 17 N 3 alloy powder, Sm having an average particle size of 0.3 μm was used.
650 g of 2O3 powder and α-Fe having an average particle size of 1.3 μm
2316 g of 2O3 powder was wet-mixed in ion-exchanged water for 2 hours using a ball mill and dried. This dried product is heated at 600 ° C. for 4 hours while flowing hydrogen gas to form S.
A mixture of m2 O3 and α-Fe was obtained. To 1000 g of the new raw material thus obtained, 200 g of a bonded magnet scrap-reduced product obtained in the same manner as in Example 1 was mixed, and otherwise the same as in Example 1 except for Sm2Fe17N3.
A system alloy powder was obtained. In this state, the r value is 11.4.

The obtained alloy powder exhibited the following magnetic properties. iHc 16.2 kOe Br 12.5 kG BHmax 36.4 MGOe However, the average particle size of the alloy powder is 2.6 μm.

Example 3 As a raw material for obtaining a new Sm 2 Fe 17 N 3 alloy powder, Sm having an average particle size of 0.3 μm was used.
650 g of 2O3 powder and α-Fe having an average particle size of 1.3 μm
2316 g of 2O3 powder was wet-mixed in ion-exchanged water for 2 hours using a ball mill and dried, and then dried at 1100 ° C. in air.
For 7 hours, and after cooling, wet grinding was performed again in ion-exchanged water for 8 hours using a ball mill, followed by drying to obtain a raw material powder having a target composition and an average particle diameter of 0.9 μm containing a double oxide. The obtained powder was subjected to X-ray diffraction measurement using Cu-Kα as a source.
-Fe2O3 is 22.8%, 31.9%, 32.7%,
From peaks at 33.1, 46.7, and 58.9, S
It was confirmed that mFeO3 crystals were formed.

With respect to 1000 g of the obtained oxide raw material, the same bonded magnet scrap as that of Example 1
The mixture was baked at 50 ° C. for 5 hours and ground to a mean particle size of 1.9 μm using a vibration mill, and 200 g of the mixture was mixed. In this state, the r value is 10.7.

The mixture was mixed with 6
The powder was heat-treated at 00 ° C for 4 hours, and the obtained powder was subjected to X-ray diffraction measurement. As a result, the peak of α-Fe2O3 at 35.6 ° disappeared, and the peak of α-Fe at 44.7 ° instead. was detected. Further, the peak relating to the SmFeO3 crystal was present without any change. After that, Sm
2Fe17N3 alloy powder was obtained.

The obtained alloy powder exhibited the following magnetic properties. iHc 10.5 kOe Br 11.6 kG BHmax 32.4 MGOe However, the average particle size of the alloy powder is 2.8 μm.

Example 4 As a raw material for obtaining a new Sm2Fe17N3 alloy powder, Sm2 having an average particle size of 0.3 μm was used.
698 g of O3 powder and 1731 g of carbonyl iron having an average particle size of 5.3 μm were mixed in a dry ball mill in a nitrogen atmosphere for 3 hours. With respect to 1000 g of this mixture, the same bonded magnet scrap as in Example 1 was baked in the air at 850 ° C. for 5 hours in the same manner as in Example 1, and 200 g of the ground magnet scrap was pulverized to an average particle size of 3.4 μm using a ball mill. Mixed. In this state, the r value is 11.4. This mixture is further mixed with granular metallic calcium 74 of 10 mm or less.
The mixture was placed in a steel container, heated in an atmosphere of argon gas at a temperature of 1150 ° C. for 1 hour, subjected to reductive diffusion, and then cooled. Thereafter, in the same manner as in Example 1, Sm2Fe1 having the following magnetic characteristics was used.
7N3 alloy powder was obtained.

The obtained alloy powder exhibited the following magnetic properties. iHc 10.2 kOe Br 11.8 kG BHmax 29.8 MGOe Average particle size 3.4 μm

Comparative Example 1 As a raw material for obtaining a new Sm2Fe17N3 alloy powder, Sm having an average particle size of 0.3 μm was used.
650 g of 2O3 powder and α-Fe having an average particle size of 1.3 μm
2688 g of 2O3 powder was wet-mixed in ion-exchanged water for 2 hours using a ball mill and dried. This dried product is heated at 600 ° C. for 4 hours while flowing hydrogen gas to form S.
A mixture of m2 O3 and α-Fe was obtained. The new raw material obtained in this manner was not mixed with a bonded magnet scrap-treated product at all, and thereafter Sm2Fe1 was treated in the same manner as in Example 1.
7N3 alloy powder was obtained. In this state, the r value is 11.4.

The obtained alloy powder exhibited the following magnetic properties. iHc 12.4 kOe Br 11.2 kG BHmax 26.7 MGOe However, the average particle size of the alloy powder is 2.9 μm.

[0056]

As described above, according to the present invention, Sm
-By regenerating the Fe-N-based alloy powder, it is possible to obtain an alloy powder having high-quality magnetic characteristics while being a recycled product. Moreover, since the bonded magnet scrap is fired at a high temperature in the atmosphere, a double oxide is generated, and the mixed oxide is mixed with a new raw material, so that the reactivity of the reduction diffusion reaction becomes higher. , Which has a higher volatile component than Fe and is expensive.
m can be reduced.

This regenerating method uses a new Sm-Fe
Since the production equipment for obtaining the -N-based alloy powder can be used, no special additional equipment is required, and economical regeneration is possible.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a relationship between a coercive force and an r value of a product of the present invention and a comparative product.

FIG. 2 is a characteristic diagram showing a relationship between coercive force and reduction / diffusion reaction temperature of a product of the present invention and a comparative product.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // C22C 33/02 H01F 1/06 A F term (reference) 4K017 AA01 BA06 BB12 CA06 DA04 EA03 EH01 EH18 FA01 FB03 FB10 4K018 AA27 AD10 BA13 BA20 BD01 KA46 5E040 AA03 AA19 CA01 HB00 HB01 HB09 HB11 HB15 HB17 NN18 5E062 CC05 CD04 CG01

Claims (3)

[Claims] An Sm-Fe-N alloy from a bonded magnet composed of a Sm-Fe-N-based alloy powder and a resin or a bonded magnet composition such as a compound used for the same.
A method for regenerating an Sm-Fe-N-based alloy powder, comprising the following steps in the order of regenerating the Sm-Fe-N-based alloy powder. (A) firing the scrap of the bonded magnet composition in a temperature range of 600 to 1500 ° C. in the presence of oxygen; (B) The obtained fired product is pulverized to have an average particle size of 1 μm to 10 μm, and if necessary, reduced in a reducing gas atmosphere of hydrogen or hydrocarbon at a temperature range of 300 to 900 ° C. (C) Sm required to produce a new alloy powder
The new raw material mixture obtained by mixing the component raw materials and the Fe component raw materials at a predetermined ratio, and the treated product obtained in the step (b) are mixed, and the stoichiometric amount required to reduce the Sm oxide in the mixture to a metal state Is reduced and diffused by mixing metal Ca or hydrogenated Ca 1.1 to 2.0 times of the above and heating in a temperature range of 900 to 1200 ° C. (D) The product obtained by the reduction diffusion treatment is placed in a gas atmosphere of nitrogen or a compound containing nitrogen in a gas atmosphere of 300 to 700.
A nitriding treatment is performed by heating in a temperature range of ° C. (E) The treated product obtained in the step (d) is put in water to disintegrate, and washed with water and acid. However, nitriding may be performed after the reduction diffusion treatment. 2. The method according to claim 1, wherein in the step (c), the mixture to be subjected to the reduction diffusion treatment is adjusted so that the r value is in a range of 10.6 to 12.4. The method for regenerating the Sm-Fe-N-based alloy powder described above Where r
The value is defined by the following equation, where ASm and AFe are the number of atoms of Sm and Fe in the raw material oxide, respectively. r = ASm / (A
Sm + AFe) × 100 3. The process according to claim 1, wherein in the step (c), the processed product obtained in the step (b) is mixed at a maximum of 400 parts by weight with respect to 100 parts by weight of the new raw material mixture. A method for regenerating an Sm-Fe-N alloy powder.