JP3078626B2 - Method for producing raw material oxide for soft ferrite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a raw material oxide for soft ferrite (hereinafter abbreviated as ferrite).

[0002]

2. Description of the Related Art Usually, a ferrite manufacturing process is performed as shown in FIG.
As shown in the production process of n-Zn ferrite, after mixing individual oxides such as manganese, nickel, magnesium, and zinc or compounds such as carbonates that change into oxides by heating at a predetermined molar ratio, It is constituted by calcining at a temperature of 1000 ° C. to obtain a raw material oxide, and pulverizing, granulating and firing. It should be noted that SiO ₂ , Ca
CO ₃ or the like is added for controlling magnetic properties, increasing the firing density, and the like.

However, this method has the following problems. (1) Since a raw material having a particle size of 0.1 to 1 μm is mixed and dispersed, the uniform mixing of the ferrite composition becomes insufficient and the magnetic properties of the product deteriorate. (2) Since the calcination process is performed at a high temperature of 800 to 1000 ° C., the cost increases.

(3) The raw material oxide is 2 to 10 μm by calcination
When pulverizing to about 1 μm in the next step, it takes a long time to pulverize, and contamination and composition deviation due to impurities mixed inevitably cannot be avoided. As a method for producing a raw material oxide which improves the above-mentioned problems (2) and (3) of the prior art, as shown in FIG. 5, an aqueous chloride mixed solution of a metal element other than zinc constituting ferrite is started. As a raw material, a production method of oxidizing and roasting it has been proposed (Japanese Patent Publication No. 63-17776).
However, even with this method, among the metal elements constituting ferrite, zinc has a high vapor pressure of chloride, so that when it is roasted simultaneously with iron chloride, manganese chloride, etc., it volatilizes and escapes, so it is oxidized and roasted at the same time. Therefore, it was necessary to separately mix in the form of an oxide in a subsequent step. In other words, for the zinc component, an oxide having a particle size of 0.1 to 1 μm must be mixed in the subsequent steps, and the number of steps is large. However, the above-mentioned problem (1) of causing non-uniformity and deteriorating the magnetic properties of the product has not been solved.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and forms an oxide obtained by oxidizing and roasting chloride and zinc oxide while preventing the escape of zinc. It is intended to be mixed in the process.

[0006]

In order to solve the above-mentioned problems, the present invention relates to a method of adding zinc oxide or a compound which becomes zinc oxide by heating to polyvinyl alcohol, polyvinyl butyral.
Tools, anionic surfactants, and water-soluble organic rust inhibitors
The aqueous solution of the non-volatile organic compound is added to form a slurry ,
The slurry (a) is mixed with an aqueous solution (b) of an iron chloride and a chloride of one or more metals selected from the group consisting of manganese, nickel, and magnesium, and oxidized and roasted. The present invention provides a method for producing a raw material oxide for ferrite, wherein the slurry (a) and the aqueous solution (b) may be simultaneously oxidized and roasted.

[0007]

The present inventors have solved the above-mentioned problems and conducted intensive studies on a method for producing a raw material oxide capable of producing ferrite having excellent characteristics at low cost. As a result, the present invention has been completed. Was. In order to improve the uniformity in the production of a raw material oxide for ferrite containing zinc, a chloride containing iron chloride, which is a main raw material, and at least one of chlorides such as manganese, nickel, magnesium, etc. A mixed aqueous solution and a zinc source that becomes zinc oxide by heating such as zinc oxide or zinc carbonate are mixed and oxidized and roasted, or a chloride mixed aqueous solution is oxidized and roasted to form an oxide in the process of forming an oxide. Uniform mixing of the sources is considered an effective method.

However, these zinc compounds have a high solubility in an acid and are easily dissolved in a chloride solution, or react with hydrochloric acid gas generated by oxidizing and roasting of the chloride to change into a form of zinc chloride. I will. As a result, zinc is volatilized during oxidative roasting, resulting in a deviation in composition and inhomogeneity. Hereinafter, the results of basic experiments that led to the present invention will be described.

In one liter of water, ferrous chloride (FeCl _2.
4H ₂ O) and manganese chloride (MnCl ₂ .4H ₂₎
O) 5.0 g of an aqueous chloride mixture mixed with 240 g
And Sample 1 or 2 shown below are mixed and placed in separate quartz crucibles, and the furnace is heated to a predetermined temperature (600 to 900 ° C.).
, And immediately inserted into the furnace. Sample 1: Slurry (suspension) in which 0.1 g of zinc oxide and 0.4 g of water were mixed Sample 2: Slurry in which 0.1 g of zinc oxide and 0.4 g of a 40% PVA (polyvinyl alcohol) aqueous solution were mixed The measurement results are shown in FIG. Sample 2 has a smaller rate of reduction of the zinc component than Sample 1. This is considered to be because PVA, which is a water-soluble organic compound, surrounded the zinc oxide particles and prevented the reaction of the zinc oxide with the chloride.

As a result, by using the zinc source as a slurry with an aqueous solution of a non-volatile organic compound, the reaction with the chloride is suppressed, and as a result, the reduction of zinc can be suppressed. It is understood that it is possible to produce an oxide for ferrite raw material by mixing or simultaneously roasting with a mixed chloride aqueous solution containing one or more of manganese, nickel, and magnesium in the form of iron chloride. The generation of the oxide by the oxidative roasting of the chloride and the mixing of the zinc oxide can be performed in one step while preventing the escape of the zinc.

As the non-volatile organic compound used in the present invention, polyvinyl alcohol (PVA), polyvinyl butyral (PVB), an anionic surfactant, a water-soluble organic rust inhibitor and the like can be used. Zinc, manganese, nickel, which are used as constituent metals of the ferrite,
Magnesium is used to obtain the effect of controlling magnetism such as power loss, magnetic permeability, saturation magnetization, and coercive force. Cu, Li, and Co are also sintered at a low temperature, control of magnetic anisotropy,
These chlorides can be added to an aqueous chloride solution in order to obtain effects such as control of microwave characteristics.

In the present invention, the spray roasting method is suitably used for the oxidative roasting.

[0013]

【Example】

[Example 1] A hydrochloric acid pickling waste liquid of a steel sheet was concentrated to a concentration containing 15 g of iron in 100 ml.
Put 25 kg of metallic manganese into 00 liter,
To completely dissolve the metal manganese (liquid A).

12.5 kg of ZnO was mixed and dispersed in a 20% by weight PVA solution together with an antifoaming agent (hereinafter referred to as liquid B). As shown in FIG. 2, the liquid A is stored in the tank 3 and the liquid B is stored in the tank 2.
After the liquid A and the liquid B were mixed with each other, the liquid was sprayed from a spray nozzle 6 through a spray device 5 as droplets 7 from the top of a spray roasting furnace 1 maintained at 810 ° C. The droplets 7 were oxidized and roasted, and an oxidized roasted product (raw material oxide for ferrite) 8 was obtained at the furnace bottom.

When the product was analyzed by X-ray diffraction qualitative analysis, the produced oxides were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, and no chloride was observed. The composition of Fe, Mn, and Zn of the produced oxide was determined by chemical analysis. The composition is F
It was determined that the sum of e, Mn, and Zn was 100% by weight. The compositional deviations of Fe, Mn, and Zn are as shown in Table 1, and it can be seen that the raw material oxide for ferrite was obtained without the compositional deviation.

The raw material oxide was added with 0.01% by weight of SiO ₂ and 0.1% by weight of CaCO ₃ , mixed with pure water, and mixed with a mixer (attritor). After mixing, the slurry was dried, PVA was added as a binder to the dried powder, and after granulation, the outer diameter was 36 mm, the inner diameter was 24 mm, and the height was 10 m.
m, and fired at 1340 ° C. in a nitrogen atmosphere containing 1% oxygen.

The magnetic properties of the obtained sintered core are 10
When the core loss at 0 kHz, 0.2 T, and 100 ° C. was measured, good magnetic properties of 280 mW / cm ³ were obtained as shown in Table 2. Example 2 Example 1 was the same as Example 1 except that 19.3 kg of ZnCO ₃ was used as a Zn source.

The oxides formed were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, and no chloride was observed. The composition of Fe, Mn and Zn was as shown in Table 1, and the composition was shifted. It can be seen that a raw material oxide for ferrite was obtained. The core loss was measured using this raw material oxide in the same manner as in Example 1, and as shown in Table 2, 290 mW / c
Good magnetic properties of m ² were obtained.

[Embodiment 3] As shown in FIG. 3, the liquid A and the liquid B prepared in the embodiment 1 are stored in the tank 3 and the tank 2, respectively.
The liquid B is sprayed simultaneously from the spray nozzle 6B into the furnace of the spray roasting furnace 1 kept at 810 ° C. as droplets 7A and 7B, respectively, and oxidized and roasted. 8A was obtained.

When the product was analyzed by X-ray diffraction qualitative analysis, the resulting oxides were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, no chloride was observed, and the compositions of Fe, Mn and Zn were as shown in Table 1. It can be seen that the raw material oxide for ferrite was obtained without causing a composition shift. When core loss was measured using this raw material oxide in the same manner as in Example 1, good magnetic properties of 280 mW / cm ³ were obtained as shown in Table 2.

Example 4 Example 1 was the same as Example 1 except that PVB was used instead of PVA. The oxides produced were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, no chloride was observed, and the compositional deviation of Fe, Mn, Zn was as shown in Table 1.
It can be seen that the raw material oxide for ferrite was obtained without causing a composition shift.

Using this raw material oxide, the core loss was measured in the same manner as in Example 1, and as shown in Table 2, 290 m
Good magnetic properties of W / cm ³ were obtained. Example 5 12.5 kg of ZnO was mixed with pure water, and an anionic surfactant was added as a dispersant to this slurry to a concentration of 1% by weight, followed by mixing (hereinafter referred to as liquid C).

The liquid A and the liquid C were spray-roasted in the same manner as in Example 1 to obtain an oxidized roasted product on the furnace bottom. The generated oxides were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, and no chloride was observed. Table 1 shows the composition of Fe, Mn and Zn.
It can be seen that the raw material oxide for ferrite was obtained without causing a composition shift. Using this raw material oxide, a core was manufactured in the same manner as in Example 1, and the core loss was measured. As shown in Table 2, 295 mW /
Good magnetic properties of cm ³ were obtained.

Example 6 12.5 kg of ZnO was mixed with pure water, and a water-soluble organic rust inhibitor was added to this slurry to a concentration of 1% by weight and mixed (hereinafter referred to as a liquid D). Example 1
Using the liquid A and the liquid D, spray roasting was performed in the same manner as described above to obtain an oxidized roasted product at the furnace bottom. The generated oxides were Fe ₂ O ₃ , Mn ₂ O ₃ and spinel, and no chloride was observed. The compositions of Fe, Mn, and Zn are as shown in Table 1, and it can be seen that a raw material oxide for ferrite was obtained without causing a composition shift.

Using this raw material oxide, a core was prepared in the same manner as in Example 1, and the core loss was measured. As shown in Table 2, good magnetic properties of 285 mW / cm ³ were obtained. [Example 7] A hydrochloric acid pickling waste liquid of a steel sheet was concentrated to a concentration containing 15 g of iron in 100 ml.
2.2 kg of metal manganese and 9.5 kg of metal magnesium were put into 80 liters, and heated to 80 ° C. to completely dissolve (solution E).

21.2 kg of ZnO was mixed with pure water, and an anionic surfactant was added to the slurry to a concentration of 5% by weight and mixed (hereinafter referred to as a liquid F). The liquid E and the liquid F were used for spray roasting in the same apparatus as in Example 1 to obtain an oxidized roasted product on the furnace bottom. The generated oxides were Fe ₂ O ₃ and Mn ₂ O ₃
And spinel without chloride, and Fe, Mn, M
The compositions of g and Zn are as shown in Table 1, and it can be seen that the raw material oxide for ferrite was obtained without causing a composition shift.

To this raw material oxide, 0.1% by weight of SiO ₂ and 0.35% by weight of CaCO ₃ were added, mixed with pure water, and mixed by a mixer. After mixing, the slurry was dried, and PVA was added as a binder to the dried powder. After granulation, the slurry was formed into a toroidal shape having an outer diameter of 36 mm, an inner diameter of 24 mm, and a height of 10 mm, and was fired at 1290 ° C. in air. The magnetic properties of the obtained core were 15.75 kHz, 0.1
When the core loss at T and 100 ° C. was measured, good magnetic characteristics of 110 mW / cm ³ were obtained as shown in Table 2.

[Embodiment 8] A hydrochloric acid pickling waste liquid of a steel sheet was
concentrated to a concentration containing 15 g of iron in ml,
2.0 kg of metallic manganese, 25.0 kg of metallic nickel and 2.0 k of metallic magnesium were added to 450 liters of this concentrated liquid.
g) and heated to 80 ° C. to completely dissolve (hereinafter referred to as liquid G).

5.0 kg of ZnO was mixed with pure water, and an anionic surfactant was added to the slurry so as to have a concentration of 5% by weight and mixed (hereinafter referred to as liquid H). Using the same apparatus as in Example 1, the liquid G and the liquid H were used for spray roasting to obtain an oxidized roasted product on the furnace bottom. The generated oxides were Fe ₂ O ₃ and spinel, and no chloride was observed. The composition of Fe, Mn, Mg, and Zn was as shown in Table 1. It can be seen that is obtained.

To this raw material oxide, 2.0% by weight of SiO ₂ and 0.05% by weight of Bi ₂ O ₃ were added, mixed with pure water, and mixed by a mixer. After mixing, the slurry was dried, and PVA was added as a binder to the dried powder. After granulation, the slurry was formed into a toroidal shape having an outer diameter of 36 mm, an inner diameter of 24 mm, and a height of 10 mm, and was fired at 1200 ° C. in air. The magnetic permeability of the obtained core was measured at 5 MHz and 25 ° C. at 1 MHz and 40 MHz.
As shown in Table 2, good magnetic properties of 50 and 48 were obtained.

Comparative Example 1 The procedure of Example 1 was repeated except that PVA was not used. The oxides produced were Fe ₂ O ₃ and Mn ₂
O ₃ and spinel, no chloride was found,
The composition deviations of Fe, Mn, and Zn are as shown in Table 1. The composition of zinc is greatly reduced, and the compositions of iron and manganese are relatively increased.

After zinc oxide was added to this raw material oxide so as to have the same composition as in Example 1, a core was prepared and the core loss was measured in the same manner as in Example 1. As shown in Table 2, 900 mW was obtained. / Cm ^{3 as} high as core loss.

[0033]

[Table 1] 酸化 Oxidation roasting products analysis results (% by weight) FeMnMgNiNiZn Example 1 68.5 22.5 9.0 Example 2 68.6 22.6 8.8 Example 3 68.5 22.8 8.7 Example 4 68.4 22.7 8.9 Example 5 68.6 22.3 9.1 Example 6 68.8 22.3 8.9 Example 7 71.5 2.2 9.4 16.9 Example 8 67.2 0 2.2 24.6 4.0 Comparative Example 1 74.9 24.8 0.3 ───────

[0034]

２ Core loss (mW / cm ³ ) Example 1 280 Example 2 290 Example 3 280 Example 4 290 Example 5 295 Example 6 285 Example 7 110 Comparative Example 1 900 ───

[0035]

[Table 3] Initial magnetic permeability 1 MHz 40 MHz Example 8 50 48よ り From Examples 1 to 8 and Comparative Example 1, according to the present invention, the components were obtained without accompanying the compositional deviation of zinc. It is possible to produce a ferrite raw material oxide with good uniform dispersibility without the need for a mixing step of zinc oxide after oxidizing and roasting, and as a result, it is possible to produce a product with good magnetic properties Became.

[0036]

According to the present invention, it is possible to mix a zinc source without escaping zinc in the oxidizing and roasting step of chloride of a metal constituting ferrite, and to separate zinc in a separate step after oxidizing and roasting. Does not need to be mixed in the form of an oxide, the calcination step is omitted, uniform dispersion is improved at low cost, and as a result, it is possible to produce a raw material oxide for ferrite with improved magnetic properties of the sintered core Became.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a furnace temperature and residual ZnO in a basic experiment.

FIG. 2 is a schematic diagram of an oxidation roasting furnace in Examples 1, 2, 4, 5, 6, 7, 8 and Comparative Example 1.

FIG. 3 is a schematic view of an oxidation roasting furnace according to a third embodiment.

FIG. 4 is a block diagram of a process according to a conventional method.

FIG. 5 is a block diagram of a process according to another conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spray roasting furnace 2, 3 Storage tank 4 Mixing tank 5 Spray device 6, 6A, 6B Spray nozzle 7, 7A, 7B Sprayed droplet 8, 8A Oxide produced from furnace bottom

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C01G 49/00 H01F 1/34

Claims (2)

(57) [Claims] 1. A method for producing zinc oxide or a compound which becomes zinc oxide by heating , comprising polyvinyl alcohol and polyvinyl butyral.
Tools, anionic surfactants, and water-soluble organic rust inhibitors
Mix the separated non-volatile organic compound aqueous solution to form a slurry .
The slurry is mixed with an aqueous solution of iron chloride and one or more metal chlorides selected from the group consisting of manganese, nickel, and magnesium, and oxidized and roasted. Of producing a raw material oxide for soft ferrite. 2. Polyvinyl alcohol or polyvinyl butyral is used as a zinc oxide or a compound which becomes zinc oxide by heating.
Tools, anionic surfactants, and water-soluble organic rust inhibitors
The aqueous solution of the non-volatile organic compound is added to form a slurry ,
A soft ferrite comprising simultaneously oxidizing and roasting the slurry and an aqueous solution of an iron chloride and a chloride of one or more metals selected from the group consisting of manganese, nickel and magnesium. Production method of raw material oxide.