JPS6184340A - Manufacture of neodymium alloy - Google Patents

Abstract

PURPOSE:To manufacture an Nd alloy suitable for use as a mother alloy for manufacturing a magnet material at a low cost by adding CaCl2 to NdF3, Ca and Fe, putting them in an iron container, and melting them by heating under specified conditions to reduce the NdF3. CONSTITUTION:CaCl2 as a flux is added to NdF3, Ca and Fe blended in a prescribed ratio, and they are put in an iron container and melted by heating to 750-1,000 deg.C in a nonoxidizing atmosphere to reduce the NdF3. Thus, an Nd-Fe alloy is manufactured. Commercially available powdery NdF3 of about -150 mesh size, commercially available powdery pure iron of <=about -32 mesh size and commercially available metallic Ca of about 1-6mm size are used as said starting materials. CaCl2 is added in about (1-2):1 molar ratio of CaCl2:CaF2. CaF2 is produced by reduction.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to the production of neodymium alloys, and more specifically, the present invention relates to the production of neodymium alloys, and more specifically, N d which is suitable as a master alloy mainly for producing magnet materials.
The present invention relates to a method for manufacturing neodymium alloys such as -F e or N (1-F a -B) at low cost.

(Prior art) Neodymium (Nd) is one of the rare earth metals (R),
It has the second largest production group after cerium (Ce) and lanthanum (La), and as a compound it is used as an additive component in ceramic pigments, ceramic capacitors, laser elements, etc. However, as a metal, there is no definite use yet, and application development is still in progress. It is actively being used, and recently its use as a magnetic material is being considered.

In particular, Sm, which has revolutionary performance, is used as a magnetic material.
-Since the appearance of Co-based rare earth permanent magnets, active research has been carried out with the aim of improving their performance and replacing them with other rare earth elements, and their relatively abundant resources have attracted attention, and their importance has been increasing. .

That is, current typical permanent magnet materials include alnico, hard ferrite 1~, and rare earth cobalt magnets such as Sm-Co. ；2nd J
(Despite the strong demand, the supply is limited due to the high price and the limited supply capacity due to the small stability of the situation and the limited supply capacity of Sm.)
・There are concerns that this will be the fastest growth since then.

On the other hand, there is active research and development into rare earth magnets that do not contain the expensive Koharu 1~, and whose main components are the ``B'' class metals, which are present in large amounts in ``Koharu'' class 2 metals. For example, as a permanent magnet, Fc 11 R
As has already been reported (Japanese Patent Application Laid-open No. II (j
5 ≤ No. 46008.59-89401), rare earth magnets mainly composed of light rare earth magnets are being used in a wide range of fields. It is hoped that it will be provided.

For example, as an example of such a rare earth magnet, N d
-F (3 series or Nd-Fe-B series magnets have also been developed, but their production a) involves melting electrolytic iron, ferroboron alloys, pure boron, and rare earth metals in a high-frequency furnace. However, although this method allows the composition to be freely selected using pure substances, it has the disadvantage that it is expensive due to the use of pure substances.

On the other hand, the molten salt electrolysis method and the thermal reduction method are considered for smelting the pure metal neodymium, but the i-editor is suitable for large-scale production, but because it retains the active high-temperature molten material for a long time,
The latter is more suitable for the current situation since there are problems with the electrolyzer construction materials. Thermal reduction d; generally involves reducing the halogen salt with Calcilla 11. At this time, Calcilla chloride 11 is mixed as a flux, placed in a reduction retort 1-, and carried out under 1 atmosphere of Δr gas. At this time, if the reduced metal is not made of tantalum or titanium, the neodymium will reduce it to 90% in a short time.
Since it is eroded, the device itself has the disadvantage of being very expensive.

In addition, since ferroboron is manufactured using tilmino 1-v, the reducing agent cannot escape, leading to the contamination of unnecessary components.
In the case of boron Ili, the only option is to use one obtained by molten salt electrolysis or one reduced with metals 1 to 11 or metal magnesium, and it is an extremely fine powder that takes time to burn off during the melting process. There are disadvantages such as high price and high price.

(Objective of the Invention) In view of these circumstances, the present invention provides a method that can be put to practical use at low cost for producing Nd-Fe-based or Nd-Fe-B-based neodymium alloys. The purpose is to provide a high-purity Neonnow 11 master alloy especially for rare earth magnet materials at a low cost.

(Structure of the Invention) In order to achieve the objective, the present inventors focused on the drawback of the conventional manufacturing method, which is that it relies on an expensive pure substance manufacturing method for mixed use of pure substances, As a result of intensive research to find a method that is fundamentally different from this manufacturing method, we found that the reaction vessel was made of inexpensive iron as a method of packaging neon 911 alloy without going through the first step of manufacturing a pure substance. This is what led to the discovery of raw materials and reaction conditions that could be effectively alloyed, and the present invention was hereby made.

That is, the feature of the present invention is that N d-F
In the production of e-alloy, neodymium fluoride (NdF3)
A raw material prepared by adding calcium chloride (Ca C]□) to calcium (Ca) and iron (Fe) as a flux was placed in an iron container and heated to 750-1 in a non-oxidizing atmosphere.
000° C. to reduce neodymium (Nd) to obtain a Nd-Fe alloy, and in the production of a Nd-Fe-B alloy,
In the second method, boric acid (B203) was further added to the raw material, and neodymium (Nd) and boron (B203) were added under the same conditions.
) is simultaneously reduced with calcium (Ca) to obtain N d -F
This method is characterized by obtaining an e-B alloy.

The present invention will be explained in detail below based on examples.

■First, the original clay F is prepared as follows.

Possible neodymium sources include oxide (Nd203), fluoride (NdF3), and chloride (Ndcl, )vF, but commercially available NdF, which is a reaction product of Nd2O3 and F2, was used, and -150 mesh A granular product of about 100 ml is preferable. Other sources of neodymium, from the free energy of formation vs. temperature diagram shown in Figure 1, are NdC, which has Mf ability, but NdC is an anhydride, or one that does not contain 1- 1! ) is difficult, it is difficult to
It is also unfavorable because of ε:. In addition, Nd2O3 is white and the CaO produced lowers the melting point of the slag by -L)/
The presence of poly[I[ is undesirable as it makes it difficult to separate the slab from the metal.

Fe is a component of the Nd-Fe magnet alloy, and in the present invention, it is alloyed with the generated Nd to lower the melting point to 1.
Lowering 71IX degree of process and 9 of iron crucible
It is effective in reducing eclipses. In addition, iron is suspended for a long time when the slag components are dissolved and becomes a molten material, and Nd
It is preferable to use a material that can be alloyed as quickly as possible with -
You can use a commercially available powdered pure iron product with a size of 32 meshes (0, 15mm) or less. 1. If you use a large lump, it will sink in the early stage of the reduction process, and the iron will be formed during the reduction reaction. Capturing Nd and B to create a low melting point alloy (N(]-F
This is undesirable because it would take away the opportunity to create 0 or N d -Fa -I3). The combination star is Nd-F
The composition of the Nd-Fe alloy is approximately 70 to 90 wt % in the case of the Nd-Fe alloy phase diagram shown in FIG. 2.

At this time, although Fe does not directly participate in the reduction reaction, it is added in an amount slightly in excess of the amount required for alloying. In addition, when using the neodymium alloy obtained by the present invention as a magnet material, it is preferable to use an ore containing few impurities.

When producing Nd-Fe-B alloy, it is necessary to add a boron source to the raw materials, and in the present invention, boric acid (B
2O2) is used. B2O3 is preferably an anhydride obtained by subjecting boric acid to strong heat treatment to remove crystallization water, and commercially available products can be used. The amount of addition may be selected so as to be close to the ratio of the Nd and B contents in the target magnet alloy. For example, N
0.5 to 5% as B in d -F e -B master alloy
can be manufactured. In addition, B2O3 is approximately 65%
is reduced and transferred to metal, while changing the slag composition to Ca.
It also has the effect of lowering the melting point and improving fluidity as a C1□-CaF,,-CaO-B203 system.

=7- Ca reduces Nd and 13, and also reduces the slag component (
It is a component that produces C8F, , C'', a O), and it is preferable to use small particles crushed to about 1 to 6 rn m with commercially available metal Calcilla 15. This mixture l is calculated according to the following formula: Approximately 1.1 to 1.5 times the theoretical amount required to reduce I and B may be added.

2NdF3+3Ca→2Nd+3C':, aF.

B20J+3Ca→2 B + 3 CaOIn addition, N
When producing a d-Fe-B alloy, B is reduced according to the latter formula above, but the reaction according to the formula
'l? B2O3 is placed at the bottom of the crucible together with calcium and flux (CaCl2) in order to perform i'J. In this case, it is more preferable if the three are Brichella 1-. Then NdF2, CaC], , Ca, Fe
The mixed raw materials are charged into a crucible and reduced.

CaC]□ is used as a flux to promote the reduction reaction of Nd and B and facilitate the separation of metal and slag. CaCl2 is formed by CaF2 produced by the reduction reaction of Nd and CaF2-CaC,l, forming a system slag, or when B2O3 is added to the raw material, Ct)O produced by the reduction reaction of B is also added. Ca C1,2-Ca F2
- Ca O-B 20 , forming a system slag, which results in the Ca Cl 2 CFI F z shown in FIG.
As can be seen from the CaO system ternary phase diagram (high CaC12 content side), CaC, which has a low melting point, is
l2 (melting point 775° C.) increases, resulting in the effect of lowering the melting point of the slab. The appropriate melting point of the slag is about 700°C, considering the reaction temperature described below. For this purpose, the composition of CaCl2 must be the C produced in the reduction reaction.
CaC in molar ratio to the amount of aF2]□:CaF2=1
~2:1 may be used as a guideline. In addition, in the case of B2O3 addition, a small amount of CaO (approximately 4 to 4
8%), the melting point of the slag is 6 as shown in Figure 3.
The temperature will be over 25°C.

(2) Next, the reaction conditions will be explained.

First, the present invention is most characterized in that an iron container is used as the reaction container. As mentioned above, containers made of tantalum, titanium, tungsten, etc. have corrosion resistance against Nd, but they are very expensive, and they also have low corrosion resistance against alloys containing O and have a short lifespan. be shortened. In contrast, the present invention makes it possible to use a much cheaper iron crucible with a reaction temperature of 1.0
If the temperature is controlled to 41.1 degrees below 00 degrees Celsius, Nd corrosion can be suppressed to a level that can be used commercially even if the steel is made of iron. Even if it is used for 11 days, there will be no problem because iron containers are cheap and can be easily replaced, and the 1.C eluted is a component of the neodymium alloy. .

Reaction i! j degree is preferably around 900℃, 750℃
If the temperature is less than 411 degrees Celsius, the reduction reaction rate will be too slow and the efficiency will be low; conversely, if the temperature exceeds I 000 degrees Cz
The reaction temperature is set at 750 to 1000° C. since the loss of 1 increases and the corrosion of the iron container by Nd increases.

The processing atmosphere is a non-oxidizing atmosphere to prevent unnecessary oxidation and evaporation of Ca. If it is popular, CalJ' oxidizes,
This is because Ca nitride is formed, leading to Ca loss. Any inert atmosphere such as argon or hydrogen atmosphere may be used. Further, in order to prevent evaporative loss of Ca, it is better to carry out the process under increased pressure, but 1 atm is also sufficient.

(Example 1) This example is a case of manufacturing a Nd-Fe alloy.

As a raw material, commercially available NdF3 of 150# and 95% purity is used.
44.0 parts by weight of commercially available metallic calcium granules with a particle size of 1-3 mm and a purity of 99.5% or higher (1.20% of the theoretical amount), a commercially available electrolytic powder with a purity of 99.99%. A 7.4-weight base of iron powder obtained by pulverizing iron to 100 meshes or less, and 60.0 parts by weight of commercially available Calcilla chloride 11 as a flux made by igniting and making it anhydrous were prepared.

First, NdF3 and CaCl2 are mixed in a predetermined number of cups,
Dehydration treatment was performed by heating at 400° C. for 1 hour. Next, put the metallic calcium and iron powder on a predetermined scale.''2 NdF 3
The mixture was added to a mixture of 1° of CaC and 1° of CaCl, mixed in a type 3 mixer, and charged into an iron crucible. Then, the iron crucible was placed in a resistance electric furnace, and after the furnace was evacuated, the Ar
The temperature was raised in the electric furnace while purging with gas and Ar gas was flowing at a flow rate of 2 to 3 Q/mjn, and the temperature was maintained at 900 to 920° C. for 1 hour, followed by spinning in a mold that had been previously dried. After cooling, the metal and slag were separated.

When this metal was analyzed, it was found that the metal was a Nd--Fe alloy having the chemical components shown in Table 1, and contained few impurities. Furthermore, as shown in Table 2, it was found that Nd was reduced in high yield and Fe yield was also high. It was confirmed that the iron crucible was hardly eroded.

Table 1 Metal analysis values (wt%) −12= Table 2 Yield (Example 2) This example is a case of manufacturing a Nd-Fe-B alloy.

As a raw material, commercially available (7)N with -1508 and 95% purity was used.
41.2 parts by weight of dF3, 3.7 parts by weight of commercially available (1)-100:Ash 8203 with a purity of 99%, particle size 1-3
22.6 parts by weight of commercially available metallic calcium granules with a purity of 99.5% or higher (120% of the theoretical amount), purity 9
7.2 parts by weight of iron powder made by pulverizing 9.99% commercially available electrolytic iron to 100 mesh or less, and 711 heavy groups, Bel! Prepared.

First, a predetermined amount of NdF3 and CaCl2 are weighed and mixed.
Dehydration treatment was performed by heating at 400° C. for 1 hour. Separately dehydrated C a Cl□ and B2O2 and Cd (
(1.2 times the theoretical weight) was formed into a briquette, placed in an iron crucible, and then metal Calcilla and iron powder were weighed on a predetermined scale and added to the /14 mixture of NdF3 and Ca CI b, and then made into a V-shaped briquette. After mixing with a mixer, the mixture was charged into an iron crucible containing the Frikera 1-. Then, the iron crucible was placed in a resistance electric furnace, and Ar gas was introduced into the furnace at a flow rate of 2 to 1.
(Heat the electric furnace y1 while flowing at 1,/min, 900~
After being held at 920° C. for 1 hour, it was cast into a mold that had been previously dried. After cooling, the metal and slag were separated.

When this metal was analyzed, it was found that the metal was a Nd-Fe-B alloy having the chemical components shown in Table 3, and that it contained few impurities. Also, as shown in Table 4, N
It was found that the reduction of d and B was carried out in high yields, and the yield of Fe was also high. It was confirmed that the iron crucible was hardly eroded.

Table 3: Metal analysis values (,B:%) Table 4: Yield (effects of the invention) As is clear from the above detailed description, the present invention performs a reduction reaction using an iron container as a reaction container. Therefore, equipment costs are low, and the range of reaction conditions that allow easy reduction can be selected, and easily available commercially available raw materials can be used, so neodymium alloys can be manufactured at low cost. In addition,
The obtained neodymium alloy is inexpensive and has high purity, so when it is used, for example, as a magnet alloy, the alloy according to the present invention is simply added to iron as a master alloy, and Nd-Fe and Nd- Fe-B magnet alloy can be manufactured,
A high-performance rare earth magnet can be obtained since it does not contain impurities that are undesirable for magnets, and since Nd and B can be added at the same time, it is suitable as a master alloy for Nd-Fe-B magnets. The practical effects of this method are extremely large, such as that it can also be applied to the production of BRACEOJIU 11 alloy.

[Brief explanation of the drawing]

Fig. 1 is a formation free energy hygrogram related to calcium reduction, Fig. 2 is a binary phase diagram of Nd-Fc, and Fig. 3 is a ternary phase diagram of CaCl2-CaF, (-CaO system. This figure shows the part on the J-group side containing A.

Claims (1)

[Claims] 1. A raw material made by adding calcium chloride as a flux to neodymium fluoride, calcium, and iron is placed in an iron container, heated and melted at 750 to 1000°C in a non-oxidizing atmosphere, and the neodymium is reduced. A method for producing a neodymium alloy, characterized in that a neodymium-iron alloy is obtained. 2. A raw material made by adding calcium chloride as a flux to neodymium fluoride, calcium, iron, and boric acid is placed in an iron container, heated and melted at 750 to 1000°C in a non-oxidizing atmosphere, and neodymium and boron are reduced to form neodymium. - A method for producing a neodymium alloy, characterized in that an iron-boron alloy is obtained.