JPH09241708A - Production by reduction diffusion method of alloy powder containing rare earth and transition metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing alloy products having high quality by improving the underwater collapsing property in calcined matter, thereby omitting a crushing stage and improving the yield of the products in production of a powder alloy by a reduction diffusion method. SOLUTION: Rare earth oxide powder, transition metal powder and other raw material powder are weighed and mixed. Further, a reducing agent sufficient for reducing the rare earth oxide powder is added and mixed to and with the mixture. The mixture is calcined by heating and holding the mixture up to and at the temp. at which the reducing agent melts or above and the temp. at which the desired alloy does not melt in the atmosphere where oxygen does not substantially exist, by which the rare earth oxide is reduced to a rare earth metal. The mixture is thereafter diffused into the transition metal powder to obtain the desired alloy. The calcined matter obtd. after cooling down to room temp. is charged into water to dissolve the residual reducing agent and the formed redox agent. The calcined matter is repetitively subjected to agitation and decantation and is washed. The settled alloy powder is separated and recovered and is dried. The alloy powder contg. the desired rare earth and transition metal is thus produced. The calcined matter is subjected to a hydrogen treatment after the calcination.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an alloy powder containing a hydrogen storage alloy, a battery material, a rare earth element useful as a permanent magnet material, and a transition metal by a reduction diffusion method. In order to improve the disintegration property of the calcined product after the calcining process in which the reduction diffusion reaction is performed, the crushing process of the calcined product is unnecessary, the cleaning efficiency and the recovery rate are improved, and the impurity content is reduced. The present invention relates to a method for producing the alloy powder by a novel reduction diffusion method.

[0002]

2. Description of the Related Art The reduction-diffusion method is cheaper in raw material than the melting method, the heat treatment temperature is low, the structure of the obtained alloy is dense, and the composition can be easily adjusted. Since it has many advantages such as no treatment and no crushing step, it is widely used for manufacturing rare earth permanent magnets.

The method for producing an alloy by this reduction diffusion method is as follows:
Rare earth oxide powder, transition metal powder, and other raw material powders are weighed and mixed, and further a reducing agent necessary for reducing the rare earth oxide powder, for example, metal calcium is added and mixed, and the mixture contains oxygen. An atmosphere that is virtually nonexistent,
For example, a temperature at which the reducing agent melts in an argon stream or in a vacuum, for example, a temperature of 820 ° C. or higher when metallic calcium is used as the reducing agent, and a temperature at which a desired alloy does not melt (usually 900 to The temperature is increased to 1200 ° C.), the rare earth oxide is reduced to a rare earth metal, the transition metal powder is diffused into a desired alloy, and the alloy is cooled to room temperature. Then, the residual reducing agent and the generated redox agent are dissolved, and stirring and decantation are repeated to wash with water, and the precipitated alloy powder is separated and recovered and dried to obtain an alloy powder containing a desired rare earth element and a transition metal. It is a thing.

In the above reduction diffusion method, a stainless steel reaction vessel is generally used as a firing furnace for firing, and a raw material mixture containing each of the above oxides is charged into the firing vessel to perform firing. Although the reduction-diffusion reaction proceeds in the mixture, there is a problem that the mixture shrinks after firing and solidifies into a solid state, which makes recovery thereof difficult.

[0005]

In particular, for example, Nd-F
When an e-B type permanent magnet alloy is produced by a reduction diffusion method by raising the firing temperature so that a partial composition of the alloy is melted like a production by a reduction diffusion method, a fired product is used. Will solidify very strongly, so in order to transfer it to the washing process, it should be roughly smashed with a hammer, etc., and about 1 cm with a crusher such as a jaw crusher.
It had to be coarsely crushed to the size of a corner. And, these crushing and crushing operations are not only dangerous operations themselves, but also it is necessary to take measures to prevent ignition and oxidation, and to reduce product yield, crush and crushing operations. It is not preferable because there is a risk of quality deterioration due to inclusion of impurities.

Further, in the case of an Sm-Co alloy or the like which is manufactured at a firing temperature that does not involve melting of a part of the composition, the fired product spontaneously disintegrates if left to stand overnight.
This also does not completely collapse, the degree of collapse differs depending on the abandoned environment such as season, weather, temperature, etc. There is a problem in quality control, and since the collapse time is long all day and night, chlorine content in the atmosphere, There is also a problem that the quality of the final product is deteriorated by absorbing nitrogen oxides.

The present invention solves the above-mentioned problems in the production of powder alloys by this kind of reduction diffusion method and improves the disintegration property of the fired product in water, thereby omitting the crushing step and thereby improving the product yield. It is an object of the present invention to provide a method for obtaining a high quality alloy product.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention is to measure rare earth oxide powder, transition metal powder and other raw material powders and mix them, and further reduce the rare earth oxide powder. Calcination is carried out by adding and mixing a sufficient reducing agent for heating the mixture to a temperature above the temperature at which the reducing agent melts in an atmosphere substantially free of oxygen and at a temperature at which the desired alloy does not melt. After reducing the rare earth oxide to a rare earth metal, it is diffused into the transition metal powder to obtain a desired alloy, cooled to room temperature, and the obtained calcined product is put into water to produce a residual reducing agent and generated. Dissolving the redox agent, washing with water by repeating stirring and decantation, separating and recovering the precipitated alloy powder, and drying to produce an alloy powder containing a desired rare earth and transition metal, The calcined product is hydrotreated after serial firing,
It is characterized by a method for producing an alloy powder containing a rare earth element and a transition metal by a reduction diffusion method.

According to the present invention, the reduction-diffusion reaction product after calcination has a significantly improved disintegration property in water, so that the crushing step can be omitted and the number of repeated decantation operations can be significantly reduced. This makes it possible to reduce the amount of waste liquid processed and further improve the recovery rate of alloy powder products.

In the present invention, the above-mentioned hydrogen treatment is preferably carried out in the firing furnace during the cooling step of the reaction product after reduction and diffusion by firing. This is because the process can be simplified and the energy consumption can be reduced. Further, the hydrogen treatment is preferably performed in a temperature range of 100 to 600 ° C. If the temperature is less than 100 ° C, the effect is small, while 60
This is because if the temperature exceeds 0 ° C., the energy consumption becomes large, and the target alloy compound may be decomposed or by-products may be generated. Furthermore, after firing, it is not necessary to cool to room temperature and then perform hydrogen treatment, and residual heat of the firing treatment may be used for heating for hydrogen treatment.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as described above, a rare earth oxide powder, a transition metal powder, and other raw material powders are weighed and mixed, and further reduced enough to reduce the rare earth oxide powder. The rare earth oxide is mixed by adding the agent and firing the mixture by maintaining the mixture at a temperature not lower than the melting temperature of the reducing agent and not melting the desired alloy in an atmosphere substantially free of oxygen. Is reduced to a rare earth metal, then this is diffused into the transition metal powder to form a desired alloy, and after cooling to room temperature, the fired product obtained is put into water to dissolve the residual reducing agent and the generated redox agent. And repeat the stirring and decantation to wash with water,
In the method for producing an alloy powder containing a desired rare earth and transition metal by separating and recovering the precipitated alloy powder, and drying,
By subjecting the reaction product obtained by reduction diffusion by calcination to hydrogen treatment, the disintegration property of the reaction product is improved,
This has succeeded in reducing the number of times of decantation repetitive operations, thereby improving the yield of alloy powder products and improving product quality.

In the present invention, the alloy powder product of interest is any alloy powder containing a rare earth (lanthanoid element including yttrium) and a transition metal (iron, cobalt, nickel) in any method of reducing and diffusing the alloy powder. It can be applied. For example, hydrogen storage alloys, battery materials, alloys for permanent magnets (for example, Sm-Co based, Sm-Fe-N
Sm-Fe-based alloy, Nd-Fe-, which is used for the production of a system-based alloy
B type, La-Ni type, Tb-Fe-Co type, Nd-Co
System, etc.), but especially Sm-Co system and Nd
When applied to the production of a —Fe—B based alloy for permanent magnets, the production method of the present invention can exert remarkable effects.

The hydrogen treatment carried out in the present invention was carried out by flowing an inert gas such as argon gas during the cooling period after the firing step in the conventional reduction diffusion method when the predetermined cooling temperature was reached. In addition, it is only necessary to replace a part or the whole of the argon gas flow with hydrogen gas for a suitable time.

As described above, the hydrogenated calcined product undergoes spontaneous disintegration simply by being exposed to the atmosphere after being cooled to room temperature, and the calcined product which has been conventionally required has a size of about 1 cm square. Not only can the coarse crushing step be omitted,
Since it disintegrates into finer particles than the particle size after the conventional coarse crushing process,
It is possible to shorten the time in the subsequent water-washing separation step, and to significantly reduce the number of times of sieving and decantation repetitive operations. As a result, the amount of waste liquid treated can be reduced, the recovery rate of alloy powder products can be improved, and the product purity can be improved. If a rotary kiln or the like is used for the hydrogen treatment, a powdered fired body can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. In Examples 1 to 8 and Comparative Examples 1 to 3, production examples of Sm-Co based alloy powders were used, and in Examples 9 to 17 and Comparative Examples 4 to 6, Nd-Fe-. The production example of the B type is shown.

Example 1 Aiming at an alloy production scale of 1.0 kg, 460 g of samarium oxide powder, 660 g of cobalt powder, 198 g of metallic calcium (1.25 times the stoichiometric amount required for reduction of samarium oxide) and anhydrous calcium chloride. 46 g (both raw materials have a purity of 99% or more) were mixed in an argon atmosphere, and the mixture was made into a stainless steel reaction vessel (firing furnace).
It is sealed inside and up to 1150 ° C in argon gas flow for about 1
The temperature rises over a period of time, and the temperature is maintained for about 4 hours and then 10
After holding at 00 ° C for 2 hours to carry out the reduction diffusion reaction, 50
After cooling to 0 ° C., the argon gas was replaced with hydrogen gas at this point. After standing in this state for 2 hours, the inside of the reaction vessel was replaced with argon gas again, then cooled to room temperature, the reaction product in the form of a lump was taken out of the vessel, and put into 50 liters of water, and stirred for 1 hour. The lumpy reaction product was sufficiently disintegrated in water to form a slurry, and a suspension containing Ca (OH) ₂ was separated from the obtained slurry, and the remainder was sieved with a 48-mesh sieve to recover the lower portion of the sieve. . Table 1 shows the collection amount
Shown in

Next, both the upper and lower sieves are mixed,
After pouring 50 liters of pure water and confirming that the alloy powder was settled, the operation of draining by decantation was repeated until the pH of the slurry became 10 or less. Table 1 shows the number of repetitions of this decantation. Then, the alloy powder under the sieve is recovered by further sieving with a 48-mesh sieve, suction-filtered and washed with ethanol.
For 8 hours drying in a vacuum of ^-2 Torr Sm-
A Co-based alloy powder product was obtained. The final product recovery amount is shown in Table 1.

Example 2 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was used as it was in argon gas. After cooling to room temperature, it was further heated to 100 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 1 to obtain Sm-
A Co-based alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 3 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was directly used in argon gas. After cooling to room temperature, it was further heated to 200 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 1 to obtain Sm-
A Co-based alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 4 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was directly used in argon gas. After cooling to room temperature, it was further heated to 300 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 1 to obtain Sm-
A Co-based alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 5 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was directly used in argon gas. After cooling to room temperature, it was further heated to 400 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 1 to obtain Sm-
A Co-based alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 6 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was used as it was in argon gas. After cooling to room temperature, it was further heated to 500 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 1 to obtain Sm-
A Co-based alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 7 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was used as it was in argon gas. After cooling to room temperature, the inside of the reaction vessel was evacuated to 10 ⁻² Torr, then hydrogen gas was introduced into the reaction vessel until it became 0.1 Torr, and left in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet-treated in the same procedure as in Example 1 to obtain an Sm-Co based alloy powder product. The amount of the under-sieve recovered after pouring the reaction product into water in this Example, p
Table 1 shows the number of decantations and the final product recovery amount up to H10 or less.

Example 8 Aiming at an alloy production scale of 1.0 kg, 460 g of samarium oxide powder, 660 g of cobalt powder, and 198 g of metallic calcium (1.25 times the stoichiometric amount required for reduction of samarium oxide, all raw materials were used). (Purity 99% or more) is mixed in an argon atmosphere, the mixture is sealed in a stainless steel reaction container, heated to 1150 ° C. in an argon gas stream over about 1 hour, and kept at the same temperature for about 4 hours. Further, the mixture was held at 1000 ° C. for 2 hours to carry out a reduction diffusion reaction and then cooled to room temperature, and the argon gas was replaced with hydrogen gas. After standing for 2 hours in this state, the inside of the container was further replaced with argon gas, and then the lumpy reaction product was taken out of the container and put into 50 liters of water, followed by stirring for 1 hour to remove the lumpy reaction product. It was sufficiently disintegrated in water to form a slurry, and a suspension of Ca (OH) ₂ was separated from the obtained slurry, and the remainder was sieved with a 48-mesh sieve to recover the lower portion of the sieve. Table 1 shows the recovery amount under the sieve.

Next, after mixing both the upper and lower sieves and pouring 50 liters of pure water, it was confirmed that the alloy powder had settled and drained by decantation. The pH of the slurry was 10 or less. Repeatedly until. Table 1 shows the number of repetitions of this decantation. Next, the alloy powder under the sieve is recovered by further sieving with a 48-mesh sieve, suction-filtered, and washed with ethanol.
After drying in a vacuum of 10 ⁻² Torr for 8 hours, S
An m-Co alloy powder product was obtained. Table 1 shows the amount of final product collected
Shown in

Comparative Example 1 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was directly used in argon gas. After cooling to room temperature, the atmosphere in the reaction vessel was replaced with hydrogen gas, and the reaction product immediately taken out of the reaction vessel without holding in the hydrogen gas atmosphere was wet-treated in the same manner as in Example 1. Then, an alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged into water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this comparative example.

Comparative Example 2 A reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was used as it was in argon gas. After cooling to room temperature, it was further heated to 650 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The bulk reaction product thus obtained was wet treated in the same manner as in Example 1 to give S.
An m-Co alloy powder product was obtained. Table 1 shows the amount of the under-sieve recovered after the reaction product was charged into water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this comparative example.

Comparative Example 3 A bulk reaction product obtained by subjecting a raw material having the same composition as in Example 1 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 1 was used as it was in argon gas. After being cooled to room temperature in, the reaction product was wet-treated in the same manner as in Example 1 to obtain an Sm-Co based alloy powder product. The amount of the under-sieve recovered after the reaction product was put into water in the present comparative example,
Table 1 shows the number of decantations until reaching pH 10 or less and the final product recovery amount.

[0029]

[Table 1] Decantation alloy powder product after water disintegration Repeated recovery amount of 48 mesh Execution number Sieving amount (g) Number of times (times) (g) ───────────── ───────────────────── Example 1 981 5 974 Example 2 979 5 972 Example 3 976 5 968 Example 4 982 5 970 Example 5 980 5 971 Example 6 971 5 963 Example 7 976 5 964 Example 8 955 6 945 Comparative Example 1 901 14 921 Comparative Example 2 968 5 964 Comparative Example 3 825 19 834 ────────────── ────────────────────

As can be seen from the results of Table 1, the samples according to Examples 1 to 8 of the present invention have a larger amount of under-sieving recovery after water disintegration and decantation than those according to Comparative Examples 1 and 3. The number of repeated operations is small, and the final product recovery amount is high. In addition, in the result of Comparative Example 2, the recovery amount after the water collapse, the number of decantation operations,
The product recovery amount is almost the same as that of the example of the present invention, but Sm ₁ Co which constitutes the main phase in the reaction product
_Five phases decomposed and cobalt, samarium hydroxide, etc. were produced, and a good magnet powder product could not be obtained as it was.

Example 9 Aiming at an alloy production scale of 1.0 kg, neodymium oxide powder 405 g, iron powder 608 g, and boron content 19.0%.
65g of ferroboron powder, 217g of metallic calcium
(Stoichiometric amount of 1.5 required for reduction of neodymium oxide
2 times) and 46 g of anhydrous calcium oxide (purity of all raw materials is 99% or more) are mixed in an argon atmosphere, the mixture is sealed in a stainless steel reaction vessel (firing furnace), and the mixture is heated to about 1000 ° C. in an argon gas stream. The temperature was raised over 1 hour, the temperature was maintained for about 2 hours to carry out a reduction diffusion reaction, and then the temperature was cooled to 500 ° C. At this point, the argon gas in the reaction vessel was replaced with hydrogen gas. After standing in this state for 2 hours, the inside of the reaction vessel was replaced with argon gas again, then cooled to room temperature, the reaction product in the form of a lump was taken out of the vessel, and put into 50 liters of water, and stirred for 1 hour. The agglomerated product was sufficiently disintegrated in water to form a slurry, and a suspension containing Ca (OH) ₂ was separated from the obtained slurry, and the remainder was sieved with a 48-mesh sieve to recover the lower portion of the sieve. The amount recovered under the sieve is shown in Table 2.

Next, both the upper and lower sieves are mixed,
After pouring 50 liters of pure water and confirming that the alloy powder was settled, the operation of draining by decantation was repeated until the pH of the slurry became 10 or less. The number of repetitions of this decantation is shown in Table 2. Then, the alloy powder under the sieve is recovered by further sieving with a 48-mesh sieve, suction-filtered and washed with ethanol.
Nd-Fe- for 8 hours drying in vacuo at ^-2 Torr
A B-based alloy powder product was obtained. The final product recovery amount is shown in Table 2.

Example 10 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was used as it was in argon gas. After cooling to room temperature, it was further heated to 100 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 11 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was used as it was in argon gas. After cooling to room temperature, it was further heated to 200 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 12 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was used as it was in argon gas. After cooling to room temperature, it was further heated to 300 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 13 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, it was further heated to 400 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 14 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, it was further heated to 500 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 15 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, it was further heated to 600 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of the final product recovered in this example.

Example 16 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was used as it was in argon gas. After cooling to room temperature, the inside of the reaction vessel was evacuated to 10 ⁻² Torr, then hydrogen gas was introduced into the reaction vessel until it became 0.1 Torr, and left in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was treated in the same manner as in Example 9 to obtain an Nd-Fe-B based alloy powder product. The amount of under-sieving recovered after the reaction product was put into water after being sieved in this example,
Table 2 shows the number of decantations until the pH reached 10 or less and the final product recovery amount.

Example 17 Aiming at an alloy production scale of 1.0 kg, neodymium oxide powder 405 g, iron powder 608 g, and boron content 19.0%.
65g of ferroboron powder, 217g of metallic calcium
(Stoichiometric amount of 1.5 required for reduction of neodymium oxide
2 times, all raw materials have a purity of 99% or more) are mixed in an argon atmosphere, the mixture is sealed in a stainless steel reaction vessel, and the temperature is raised to 1000 ° C. in an argon gas stream over about 1 hour. The temperature was maintained for about 2 hours to carry out a reduction diffusion reaction and then cooled to room temperature. At this point, the argon gas in the reaction vessel was replaced with hydrogen gas. After leaving for 2 hours in this state, the inside of the reaction vessel was replaced with argon gas again, and the lumpy reaction product was taken out of the vessel and put into 50 liters of water, and stirred for 1 hour to sufficiently remove the lumpy reaction product. It is disintegrated in water to form a slurry, and a suspension containing Ca (OH) ₂ is separated from the obtained slurry, and the remaining 4
The bottom of the sieve was recovered by sieving with an 8 mesh sieve. The amount recovered under the sieve is shown in Table 2.

Next, both the upper and lower sieves are mixed,
After pouring 50 liters of pure water and confirming that the alloy powder was settled, the operation of draining by decantation was repeated until the pH of the slurry became 10 or less. The number of repetitions of this decantation is shown in Table 2. Then, the alloy powder under the sieve is recovered by further sieving with a 48-mesh sieve, suction-filtered and washed with ethanol.
-Nd-Fe was dried for 8 hours in a vacuum of ^-2 Torr.
A B-based alloy powder product was obtained. The final product recovery amount is shown in Table 2.

Comparative Example 4 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, the atmosphere in the reaction vessel was replaced with hydrogen gas, and the reaction product immediately taken out of the reaction vessel was wet-processed in the same manner as in Example 9 without holding in the hydrogen gas atmosphere. It processed and the Nd-Fe-B type | system | group alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of final product recovered in this comparative example.

Comparative Example 5 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, it was further heated to 650 ° C. in argon gas, the atmosphere in the reaction vessel was replaced with hydrogen gas at the same temperature, and heat treatment was performed in a hydrogen atmosphere for 2 hours. The reaction product thus obtained was wet treated in the same procedure as in Example 9 to obtain Nd-
An Fe-B based alloy powder product was obtained. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of final product recovered in this comparative example.

Comparative Example 6 A reaction product obtained by subjecting a raw material having the same composition as in Example 9 to a reduction diffusion reaction in a reaction vessel under the same reaction conditions as in Example 9 was directly used in argon gas. After cooling to room temperature, the obtained reaction product was wet-treated in the same procedure as in Example 9 to obtain an Nd-Fe-B based alloy powder product. Table 2 shows the amount of the under-sieve recovered after the reaction product was charged in water and sieved, the number of decantations until reaching pH 10 or less, and the amount of final product recovered in this comparative example.

[0045]

[Table 2] Decantation alloy powder product after water disintegration Repeated recovery amount of 48 mesh Implementation number Execution amount (g) Number of times (times) (g) ───────────── ───────────────────── Example 9 982 5 972 Example 10 988 5 974 Example 11 984 5 973 Example 12 982 5 971 Example 13 987 5 975 Example 14 985 5 973 Example 15 978 5 965 Example 16 932 6 925 Example 17 925 6 910 Comparative Example 4 902 12 918 Comparative Example 5 987 5 974 Comparative Example 6 715 20 685 ──────── ──────────────────────────

As can be seen from the results in Table 2, the samples according to Examples 9 to 17 of the present invention had a larger amount of under-sieving recovery after water disintegration than the samples according to Comparative Examples 4 and 6, and repeated decantation. The number of operations is small, and the final product recovery amount is high. Further, in the results of Comparative Example 5, the recovery amount after decomposing in water, the number of decantation operations, and the product recovery amount are almost the same as those in the example of the present invention, but the main phase in the reaction product Which constitutes Nd ₂ Fe ₁₄
Phase B decomposed and αFe, Fe ₂ B, neodymium hydride, etc. were produced, and good magnet powder products could not be obtained as they were.

[0047]

As described above, according to the present invention,
By subjecting the reaction product after the reduction diffusion reaction to hydrogen treatment, the disintegration property of the reaction product is improved, and the pH lowering rate in the decantation process is faster, so that the number of drainage-injection repetitions can be reduced, The amount of alkaline waste liquid processed is reduced. In addition, along with this, the recovery rate of the alloy powder product is improved, and the wet treatment process can be significantly shortened, which is a great advantage.

Claims (4)

[Claims] 1. A rare earth oxide powder, a transition metal powder, and other raw material powders are weighed and mixed, and further a reducing agent sufficient to reduce the rare earth oxide powder is added and mixed, and the mixture is mixed with oxygen. After reducing the rare earth oxide to a rare earth metal by firing by holding the temperature above the temperature at which the reducing agent melts in a substantially nonexistent atmosphere and at a temperature at which the desired alloy does not dissolve, the rare earth oxide is reduced to the above Diffusion into the transition metal powder to form the desired alloy, cooling to room temperature, and then pouring the resulting fired product into water to dissolve the residual reducing agent and the generated redox agent, and repeat stirring and decantation to wash with water. Then, the precipitated alloy powder is separated and collected, and a method for producing an alloy powder containing a desired rare earth or transition metal by drying, characterized in that the fired product is subjected to hydrogen treatment after the firing. A method for producing an alloy powder containing a rare earth element or a transition metal by a reduction diffusion method. 2. The method for producing an alloy powder containing a rare earth element and a transition metal by a reduction diffusion method according to claim 1, wherein the hydrogen treatment of the fired product is performed in a firing furnace during cooling after firing. 3. The hydrogen treatment of the fired product is carried out by 100 to 60.
The method for producing an alloy powder containing a rare earth metal and a transition metal by the reduction diffusion method according to claim 1 or 2, which is performed at 0 ° C. 4. The alloy powder containing a rare earth or a transition metal is Sm—Co based alloy powder or Nd—Fe—B based alloy powder.
A method for producing an alloy powder containing a rare earth or a transition metal according to the item 1 by a reduction diffusion method.