JPH022810B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a metal oxide magnetic material by a wet process. [Prior Art] Usually, a soft magnetic oxide magnetic material, ie, ferrite, is represented by the basic formula of M ²⁺ O.Fe ₂ O ₃ .
Here, M ²⁺ is Fe, Mn, Ni, Cu, Mg,
It is represented by Zn, Co, etc., and a part of it can be replaced with other metals. Furthermore, combinations of these divalent metals produce products exhibiting their own characteristic magnetic properties, so they are appropriately selected and manufactured to suit the intended use. In order to synthesize this basic type of magnetic material, methods such as synthesis using oxides of the above metals, oxides and salts, salts and salts, or synthesis in solutions have been reported. [Problems to be Solved by the Invention] In contrast to these known methods for producing ferrite, the present invention uses a ferromanganese alloy to easily and quickly process pulverization, and
This paper proposes a new method for stably and inexpensively synthesizing ferrite. That is, even if ferromanganese or ferronickel is ground as it is and other metal oxides are added, it is difficult to synthesize high-quality ferrite. Oxidized materials such as pulverized ferromanganese or ferronitkel or sprayed melts of alloys have low activity and also cause segregation. Therefore, the magnetic material made by it is
The anisotropy becomes locally large and also causes non-uniformity. The main reason for this is that proper powder cannot be obtained due to the characteristics peculiar to the ferromanganese alloy, such as its toughness and malleability. This invention eliminates these manufacturing defects and
We succeeded in producing ferrite magnetic material at an extremely low cost. [Means for Solving the Problems] That is, the present invention provides an oxide of Fe, Mn, Ni, Cu, Mg, Co, or a substance that becomes the oxide upon heating, for one or more of ferromanganese and ferronitkel. When preparing a mixture by adding one or more substances (excluding metals), the content as Fe ₂ O ₃ in the mixture should be 36 to 60 mol%, Mn, Ni, Cu, Mg,
Zn, Co oxides, or one or more substances that become the oxides when heated, are adjusted and added in a range of 40 to 64 mol%, and through the process of wet grinding, mixing, and dehydration accompanied by oxidation, A method for producing metal oxide magnetic material by heating it to 1450℃. A method for producing a metal oxide magnetic material by calcining the final mixture according to item 1 at 700 to 1250°C, re-pulverizing it, and then heating it to 800 to 1450°C. A method for producing a metal oxide magnetic material using ferromanganese, ferronickel, electrolytic iron, or electrolytic manganese as the crushing media described in item 1, and using the worn components of the media as they are as component oxides. is to provide. First, considering the substance ferromanganese (substituting it with ferronic acid will produce the same results below) as a representative example of ferroalloy, its manufacturing method involves adding coke, Cao, SiO ₂ , etc. as a reducing agent to manganese ore. are mixed in an appropriate ratio and reduced and melted in an electric furnace to obtain a ferromanganese alloy. In this case, the alloy manufactured according to JIS is
High carbon C...7.5% or less, medium carbon C...2% or less,
Low carbon C... There are three types of 1% or less. The malleability of these ferromanganese increases as the iron content increases and the carbon content decreases. Usually, low-carbon ferroalloys (ferromanganese, ferronickel) are expensive, and high-carbon types are half the price. In this invention, for convenience of ferrite formation, a high-carbon, brittle raw material is used to facilitate pulverization and to reduce the cost. That is, carbon containing at least 3% or more, preferably 7 to 10%, is used. Naturally, there is no reason to reject this, since a higher carbon content makes crushing easier and thus reduces the crushing cost. However, in this invention, considering the need to oxidize the alloy, the low silicon content, the reduction in manganese content, and the range in which the alloy can be tapped due to the manufacturing technology, the carbon content is inevitably increased. limited. As a first method, it is necessary to crush the manganese alloy. In particular, the performance of manganese alloys significantly deteriorates depending on the particle size of the powder, so careful adjustment is required. There are many types of crushing, including ball mills, vibration mills, atomizers, impact column crushing, and others. Here, the material is ground in an inert gas using a vibration mill, a ball mill, or the like. First, the grinding media should be of the same quality as the material to be ground or one whose composition can be corrected later, and the diameters should be of different sizes (large, medium, and small), and the weight of the small diameter media should be 40 to 90%. We suggest that the model be equipped with a classification device. The large diameter of this alloy steel ingot for media is 40 to 20 mm, the medium diameter is 10 to 8 mm, and the small diameter is about 5 mm. However, these diameter values are approximate numbers, and there is no problem in using diameters that are higher or lower than each designated value. Moreover, it is also possible to use normal steel media in part. The steel ingot can also be used as a medium, even if it is arbitrarily cut and has an irregular shape. The angled media wears out during use and becomes rounded, resembling an irregular spherical shape. Further, after long-term use, the media becomes irregular in diameter, or becomes smaller in diameter than the medium diameter, or becomes fine particles, and is crushed into powder by the steel ingot that is replenished later. Powder that has undergone such a pulverization process has a defect in that the particle size distribution becomes wide. This can be solved by additionally operating a classifier. [Function] Next, there are matters to be especially careful about during work. Metal powders with a size of 3 μm or less, especially powders of 0.5 μm or less, are fired even in air at room temperature. This phenomenon occurs in the case of powder particles, and if they are suspended in the air, an explosive state will appear depending on overall conditions such as temperature rise rate, pressure rise rate, and air mixing ratio. This is exactly the same for high carbon ferromanganese. Therefore, if the coarse particles are roasted and oxidized in order to avoid this problem, the oxide that is the object of the present invention will be inconvenient.
An example is shown below. In other words, the oxidation state of the particles of ferromanganese powder heated to 1000℃ using the usual heating method is
Considering the results measured with a line microanalyzer, the results are as shown in Figure 1. First, some of the carbon evaporates as CO gas, and Mn becomes MnO.
Forms the epidermal layer. Along with this, Fe is activated by carbon, liberated with the generation of MnO, and diffused into the alloy, and the small amount of Fe that remains becomes Fe ₃ O ₄
becomes. These are shown in Figure 1a. Here, M is MnO, M″F is a mixed layer of MnO and Fe ₃ O ₄ , H.
F is a line showing the maximum value of Fe metal concentration, and F and M are model diagrams showing ferromanganese layers, respectively. In the second stage, the MnO in the epidermal layer is slightly reduced to Mn ₃ O ₄
, the MnO region expands inside the alloy and Fe
By the same process as before, a high Fe concentration layer is formed surrounding the alloy layer of the initial composition. This is shown in Figure 1b. Here, M is Mn ₃ O ₄ , M
F is Mn ₃ O ₄ and Fe ₃ O ₄ , M・F is MnO and Fe ₃ O ₄ , but mainly the MnO layer, H・F′ is the layer containing the highest Fe concentration, and F・M is the ferromanganese layer. It is a model diagram showing each. This oxidation process proceeds by the same mechanism regardless of the size of the powder, but in the later stage of oxidation of powder with a large particle size, a layer of higher concentration of Fe is generated, which exceeds the Fe concentration in the center of the alloy. Rise. This is shown in Fe2 in Figure 2. Here, Fe1 indicates the change in Fe concentration in the alloy during the first stage of oxidation, Fe2,
Fe3 indicates the deviation in Fe concentration during the progress of oxidation in the second and third stages, and oxides such as Mn and Fe are omitted. In this way, when the segregated particles are oxidized, Fe
It becomes an oxide with its concentration segregated. The following is an example of the characteristics when the ferromanganese powder that has undergone this oxidation process is used for manganese ferrite by adjusting the ingredients so that it has the required composition.

【table】

[Example 1]

30g of high carbon ferromanganese coarse powder,
Fe ₂ O ₃ 376g, ZnO 3.5g, CaO 0.05g, SiO ₂ 0.01g
Weigh out the slurry, add water to make a 50% slurry, and grind for 5 hours in a vented vibration mill. The pulverized slurry was dehydrated, made into pellets, calcined at 1000°C for 2 hours, and then wet-pulverized for 2 hours. Then, dehydrate it, add some binder and shape it into a donut shape.
Heated at 1280°C for 3 hours and cooled in _N2 atmosphere containing 0.25% _O2 . The characteristics of the sample are shown below. μ ₀ Q tand/μ ₀ Bm 2150 45 1×10 ^-5 5300 [Example 2] High carbon ferromanganese coarse powder 300g, electrolytic iron powder
Weigh out 651 g and 0.95 g of CoO, and add equal amounts of water and H ₂ O ₂ water.
Put 100g into a vented vibration mill and grind for 8 hours.
Next, 100 g of H ₂ O ₂ water was added, the mixture was pulverized for 3 hours, dehydrated, and then treated in the same manner as in Example 1. μ ₀ Q Bm 2450 60 5100 [Example 3] Weighed 25 g of FeSO ₄ 7H _{2 O} to 300 g of high carbon ferromanganese and 3 g of flaky ferronitkel,
Add an equal amount of hot water to these and put it into a vented rubber-lined ball mill, blow in hot air containing steam using a ferromanganese media, replenish hot water, and grind for 10 hours. to this,
Fe ₂ O ₃ 1495g, MgO170g, ZnO257.9g,
Add 5g of CaCO ₃ and the same amount of water as the added oxide.
Grind for 2 hours, mix and dehydrate into pellets, 1000
Calcinate at ℃ for 2 hours. After that, it was crushed for 10 hours, formed into a donut shape at a pressure of 0.8 tons/ ^cm3 , and heated at 1250℃.
Cool in air for 4 hours. The characteristics of this sample are shown below. μ ₀ ; 4500 ρ; 1.25×10 ⁷ Ω-cm [Effects of the Invention] According to this invention, since "wet grinding with oxidation" is used, embrittlement of the metal surface and repeated scraping of the part are caused. Therefore, it is extremely easy to pulverize and can be processed in a short time. Moreover, it can be made into powder particles with a size of 1μ or less. Additionally, no dust is generated during processing. In this invention, the use of "ferroalloy (particularly high carbon type material)" and the short processing time as described above combine to increase the productivity of the magnetic material, and
It can be provided at a very low price.

[Brief explanation of drawings]

Figure 1 a is a cross-sectional view of a ferromanganese alloy particle in the process of oxidation, b is a cross-sectional view of a particle in which the oxidation of a has further progressed, and figure 2 is a view from the surface of the ferromanganese alloy particle when it is oxidized. FIG. 3, which shows the deviation of the Fe concentration up to the center, is a diagram showing the relationship between the grinding time and particle size of the ferromanganese alloy under various conditions.

Claims (1)

[Claims] 1. Oxides of Fe, Mn, Ni, Cu, Mg, Co for one or more of ferromanganese and ferronitkel,
Or, when preparing a mixture by adding one or more substances (excluding metals) that become the oxide when heated, the content as Fe ₂ O ₃ in the mixture is reduced to 36
~60 mol%, oxides of Mn, Ni, Cu, Mg, Zn, Co, or one or more substances that become the oxides when heated are added in an adjusted range of 40 to 64 mol% to prevent oxidation. 800 ~ through the accompanying wet grinding, mixing, and dehydration process
A method for producing metal oxide magnetic material by heating it to 1450℃. 2. The final mixture according to claim 1,
A method for producing metal oxide magnetic material by calcining at 700-1250°C, re-grinding, and then heating to 800-1450°C. 3. A method for producing a metal oxide magnetic material using ferromanganese, ferronickel, electrolytic iron, or electrolytic manganese as the pulverizing media according to claim 1, and using the worn components of the media as they are as component oxides.