JP2846147B2 - 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.

[0002]

2. Description of the Related Art As shown in FIG. 3, a process for producing MnZn ferrite is usually carried out by using individual oxides of iron, manganese, nickel, magnesium and zinc or compounds such as carbonates which can be easily converted into oxides by heating. Are mixed at a predetermined molar ratio, and then calcined at a temperature of 800 to 1000 ° C., followed by pulverization, granulation, and firing. However, this method has the following problems. (1) In order to mix and disperse a raw material oxide having a particle diameter of 0.1 to 1 μm, uniform mixing of the composition becomes insufficient and the magnetic properties of the product deteriorate. (2) The cost increases because the calcination process is performed at a high temperature of 800 to 1000 ° C. (3) In the calcination step, the magnetic powder grows to a particle size of 2 to 10 μm, and in the next pulverization step, when pulverizing to about 1 μm, it takes a long time to pulverize, and contamination and deviation in composition due to impurities are caused. Unavoidable.

[0003]

Therefore, as a method of manufacturing a soft ferrite which solves the above-mentioned problems (2) and (3) of the prior art, as shown in FIG. A production method has been proposed in which a mixed aqueous solution is used as a starting material to oxidize and roast it (Japanese Patent Publication No. 63-17776). However, according to this method, among the metal elements constituting soft ferrite, zinc having a high vapor pressure of chloride cannot be simultaneously oxidized and roasted. Therefore, it is necessary to mix zinc in the form of an oxide in a later step. there were. In other words, for the zinc component, 0.1.
An oxide having a particle size of 1 to 1 μm must be mixed in a subsequent step, and therefore the zinc component is not sufficiently mixed uniformly in the raw material, resulting in a non-uniform composition and deteriorating the magnetic properties of the product. The problem (1) described above was not solved.

An object of the present invention is to solve the above-mentioned problems and to provide a method for producing a raw material oxide capable of producing a soft ferrite having excellent characteristics at low cost. As a result, it was found that by oxidizing and roasting the mixed chloride a plurality of times at different temperatures, it is possible to produce a soft ferrite raw material oxide having good uniformity of the components of the raw material and good magnetic properties of the product. As a result, the following invention has been completed.

[0005]

That is, according to the present invention, a mixed chloride of iron chloride, one or more of manganese, nickel and magnesium chloride and zinc chloride is heated to 600 ° C.
A method for producing a raw material oxide for soft ferrite, comprising performing oxidative roasting at a first temperature described below, and thereafter performing oxidative roasting at a second temperature higher than the first temperature. .

Here, the mixed chloride may be a dry mixed powder or solid, or a liquid dissolved in water or an organic solvent.

[0007]

[Function] In the production of soft ferrite raw material oxide,
In order to improve the uniformity of the composition, iron chloride, which is a main raw material, a mixture of chlorides containing at least one of manganese, nickel and magnesium chloride, and zinc chloride are simultaneously oxidized and roasted. Is considered one of the most effective methods. That is, by uniformly dispersing and mixing predetermined metal ions in the form of a solution and then thermally decomposing, an oxide raw material in which the component elements are mixed at the atomic level can be produced. Alternatively, it is also conceivable to oxidize and roast after making a chloride dried product from the solution with uniform dispersion and mixing.

However, zinc chloride has a high vapor pressure,
In the prior art, there has been a problem that evaporation and volatilization occur during the thermal decomposition process, thereby causing a composition deviation and a non-uniform composition. However, the oxidative roasting temperature is controlled, and in the first-stage oxidative roasting, the zinc chloride is changed to an oxide having a low vapor pressure before evaporating, and then the second-stage oxidative roasting is performed. By oxidizing and roasting other remaining chlorides, the iron chloride and the chloride containing at least one of manganese, nickel and magnesium chlorides, It has been found that zinc can be simultaneously oxidized and roasted.

The upper limit of the roasting temperature in the first stage may be set to a temperature that can be changed to an oxide or an oxide containing zinc without evaporation of zinc chloride as a result of repeated experiments under various conditions. No need to heat up. As is apparent from the first embodiment, the temperature is desirably 600 ° C. or lower. The lower limit may be at least the reaction start temperature at which zinc chloride changes to an oxide, and when manganese chloride is used, 250 ° C. is desirable.

The method of oxidative roasting is only required to be capable of performing two-stage roasting. For mass production, a double rotary kiln, a double spray roasting furnace, a combination of a rotary kiln and a spray roasting furnace, or the like is used. A method in which an existing roasting furnace is continuously used in the process may be used, or a two-stage roasting may be performed by forming a temperature distribution from the inlet to the outlet of a sample in one roasting furnace. Although the mass productivity is somewhat inferior, two-stage roasting may be performed by controlling the temperature in a batch furnace.

Regarding the form of the raw material to be oxidized and roasted, a mixed chloride powder of iron chloride and at least one of manganese, nickel and magnesium chloride and zinc chloride is a dried mixed chloride powder or solid. Or a liquid in which a mixed chloride is dissolved in water or an organic solvent.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples. [Example 1] Reagent grade iron chloride, manganese chloride, and zinc chloride were mixed at a composition ratio of Fe, Mn, and Zn at a weight ratio of 3: 1: 0.4, and dissolved in pure water. The water content of this chloride solution was evaporated to obtain a dry chloride. This chloride was crushed in an alumina mortar in a nitrogen atmosphere.

The above powder was inserted into a horizontal tubular furnace maintained at a predetermined temperature and oxidized and roasted. The crystal structure and composition analysis of the generated oxide were performed by changing the oxidation roasting temperature during the oxidation roasting.
The composition was determined so that the weight percentages of Fe, Mn, and Zn became 100%, and the presence or absence of a composition deviation was shown. The crystal structure was examined by X-ray diffraction qualitative analysis. Table 1 shows the results. If the oxidation roasting temperature is lower than 250 ° C., zinc chloride remains. On the other hand, if the oxidizing roasting temperature exceeds 600 ° C., the composition shifts. Therefore, the first stage oxidation roasting temperature is 2
It is necessary to set the temperature between 50 ° C and 600 ° C.

The sample subjected to the first-stage oxidation roasting at 400 ° C. was subjected to the second-stage oxidation roasting in a horizontal tubular furnace maintained at a temperature of 840 ° C. About the obtained oxidation roasting, the composition of Fe, Mn, and Zn was calculated | required by the chemical analysis.
The composition was determined such that the total concentration of Fe, Mn, and Zn was 100% by weight. The compositions of Fe, Mn, and Zn are as shown in Table 2, and it can be seen that a soft ferrite raw material oxide was obtained without causing a composition shift.

To this raw material oxide, 0.01% by weight of SiO ₂ and 0.1% by weight of CaCO ₃ were added, and pure water was added, followed by mixing with an attritor. After mixing, the slurry is dried, and PVA is added as a binder to the dried powder,
After granulation, it 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 fired at 1320 ° C. in a nitrogen atmosphere containing 1% oxygen.

The magnetic properties of the obtained sintered core are 10
When core loss was measured at 0 kHz, 200 mT, and 100 ° C., good magnetic properties of 270 mW / cm ³ were obtained as shown in Table 3. [Example 2] A hydrochloric acid pickling waste liquid of a steel sheet was concentrated to a concentration containing 30 g of iron in 100 ml.
25 kg of metallic manganese and metallic zinc in 50 liters.
Then, 0 kg was charged and the mixture was heated to 80 ° C. to completely dissolve.

In this chloride mixed solution, PVA was mixed and dispersed together with an antifoaming agent, and granulated by a spray dryer. This granulated powder 1 was oxidized and roasted at a temperature of 450 ° C. as shown in FIG.
To the rotary kiln 2, which is oxidized and roasted in the first stage by the rotary kiln 2,
The second stage of oxidative roasting was carried out in a rotary kiln 3 kept at a temperature of ° C.

The product phase obtained from the outlet of the rotary kiln 3 was analyzed by X-ray diffraction qualitative analysis to find that the product phase was Fe ₂ O ₃ , Mn ₂ O ₃ , and spinel. The composition of Fe, Mn, and Zn was determined by chemical analysis.
The composition was determined such that the total concentration of Fe, Mn, and Zn was 100% by weight. The compositions of Fe, Mn, and Zn are as shown in Table 2, and it can be seen that a soft ferrite raw material oxide was obtained without causing a composition shift.

To this raw material oxide, 0.01% by weight of SiO ₂ and 0.1% by weight of CaCO ₃ were added, pure water was added, and the mixture was mixed with an 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.

As the magnetic properties of the obtained sintered core, 10
When core loss was measured at 0 kHz, 200 mT, and 100 ° C., good magnetic properties of 275 mW / cm ³ were obtained as shown in Table 3. [Example 3] A hydrochloric acid pickling waste liquid of a steel sheet was concentrated to a concentration containing 30 g of iron in 100 ml.
25 kg of metallic manganese and metallic zinc in 50 liters.
Then, 0 kg was charged and the mixture was heated to 80 ° C. to completely dissolve.

In this chloride mixed solution, PVA was mixed and dispersed together with an antifoaming agent, and granulated by a spray dryer. This granulated powder 1 was oxidized and roasted at a temperature of 400 ° C. as shown in FIG.
Was oxidized and roasted by a rotary kiln 5 held in the above-mentioned manner, and a produced powder 6 was obtained from an outlet. The powder 6 obtained from the outlet of the rotary kiln 5 was injected by an injection device 7 into a vertical injection furnace 8 maintained at 850 ° C. as shown in FIG. X-ray diffraction qualitative analysis revealed that the formed phases of the formed powder were Fe ₂ O ₃ , Mn ₂ O ₃ , and a spinel structure.

The compositions of Fe, Mn, and Zn were determined by chemical analysis. The composition is 100% by weight of the total concentration of Fe, Mn and Zn.
I decided to be. Table 2 shows the composition of Fe, Mn, and Zn.
As can be seen from the graph, a soft ferrite raw material oxide was obtained without causing a composition shift. 0.01% by weight of SiO ₂ was added to this raw material oxide,
0.1% by weight of CO ₃ was added, pure water was mixed, and mixing was performed with an attritor. After mixing, the slurry is dried, PVA is added as a binder to this dry powder, and after granulation,
It 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 1340 ° C. in a nitrogen atmosphere containing 1% oxygen.

As the magnetic properties of the obtained sintered core, 10
When core loss was measured at 0 kHz, 200 mT, and 100 ° C., good magnetic properties of 280 mW / cm ³ were obtained as shown in Table 3. Example 4 Iron chloride as a reagent was dissolved in ethyl alcohol to a concentration containing 30 g of iron in 100 ml, and manganese chloride and zinc chloride were further added. The component ratio of iron, manganese, and zinc was 3: 1: 0.4.

The chloride mixed solution is oxidized and roasted at a temperature of 400.
Oxidation roasting in spray roasting furnace maintained at ℃, generated from outlet
A powder was obtained. The powder obtained from the outlet was kept at 850 ° C.
The powder was injected into a vertical injection furnace, and the resulting powder was obtained from the furnace bottom. X-ray
When the diffraction qualitative analysis was performed, the product phase of this product powder was
Fe _Two O_Three , Mn_Two O_Three And a spinel structure.

The compositions of Fe, Mn, and Zn were determined by chemical analysis. The composition was determined such that the total concentration of Fe, Mn, and Zn was 100% by weight. The compositions of Fe, Mn, and Zn are as shown in Table 2, and it can be seen that a soft ferrite raw material oxide was obtained without causing a composition shift. 0.01% by weight of SiO ₂ was added to this raw material oxide,
0.1% by weight of CO ₃ was added, pure water was mixed, and mixing was performed with an attritor. After mixing, the slurry is dried, PVA is added as a binder to this dry powder, and after granulation,
It 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 1340 ° C. in a nitrogen atmosphere containing 1% of oxygen.

As magnetic properties of the obtained sintered core, 10
When core loss was measured at 0 kHz, 200 mT, and 100 ° C., good magnetic properties of 265 mW / cm ³ were obtained as shown in Table 3. [Comparative Example 1] The granulated powder 1 produced in Example 2 was sprayed from the top of a spray roasting furnace maintained at an oxidation roasting temperature of 840 ° C as shown in Fig. 2 without passing through a rotary kiln 5. The granulated powder 1 was oxidized and roasted to obtain an oxidized roasted product on the furnace bottom.

X-ray diffraction qualitative analysis revealed that the product was Fe ₂ O ₃ , Mn ₂ O ₃ , and spinel, and no chloride could be confirmed. Fe, Mn, Z by chemical analysis
The composition of n was determined. The composition is such that the total concentration of Fe, Mn and Zn is 1
It was determined to be 00% by weight. The compositions of Fe, Mn, and Zn are as shown in Table 2. The composition of zinc is greatly reduced, and the compositions of iron and manganese are relatively increased.

After adjusting the composition by adding zinc oxide to this product so as to have the same composition as that of Example 2,
0.01% by weight of iO ₂ and 0.1% by weight of CaCO ₃ were added, mixed with pure water, and mixed with an 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 and the inner diameter was 24.
mm, 10mm height to form a tridal, 134
Calcination was performed at 0 ° C. in a nitrogen atmosphere containing 1% of oxygen.

As the magnetic properties of the obtained sintered core, 10
When the core loss at 0 kHz, 200 mT, and 100 ° C. was measured, a magnetic characteristic of 900 mW / cm ³ was obtained as shown in Table 3. As is clear from Examples 1, 2, 3, 4 and Comparative Example 1,
According to the present invention, it is possible to produce a soft ferrite raw material oxide of iron, manganese, and zinc with good dispersibility without accompanying a composition deviation of zinc, and as a result, produce a product having good magnetic properties. It became possible.

[0030]

[Table 1]

[0031]

Table 2 結果 Analysis results (% by weight) Fe Mn Zn Examples Composition after roasting of 1 68.4 22.7 8.9 Composition after roasting of Example 2 68.6 22.7 8.7 Composition after roasting of Example 3 67.3 22.8 8 8.9 Composition after roasting of Example 4 67.6 22.6 8.8 Composition after roasting of Comparative Example 1 74.9 24.8 0.3 ───────────────────────

[0032]

[Table 3] Core loss (100kHz, 0.2T, 100 ℃) Example 1 270 mW / cm ³ Example 2 275 mW / cm ³ Example 3 280 mW / cm ³ Example 4 265 mW / cm ³ Comparative Example 2 900 mW / cm ³ } ────────────────────

[0033]

As described above, according to the present invention, 60
Oxidizing roasting is performed at a first temperature of 0 ° C. or lower and then oxidizing roasting at a second temperature higher than the first temperature. Of these, it has become possible to oxidize and roast zinc chloride and a mixed chloride of iron and manganese (or nickel, magnesium, etc.) having low vapor pressures as chlorides. By simultaneously reacting the metal elements constituting the soft ferrite as described above, (1) the calcination step is omitted, and the cost is reduced.
(2) In order to produce oxides of iron, manganese (or nickel, magnesium, etc.) and zinc at once in a roasting furnace without mixing zinc in the form of oxides in the post-process after roasting And the uniform dispersibility was improved. As a result, it became possible to produce a raw material oxide for soft ferrite in which the magnetic properties of the sintered core were also improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a two-stage oxidizing roasting furnace for a raw material oxide for soft ferrite used in Example 2.

FIG. 2 is a schematic view of a two-stage oxidizing and roasting furnace for a raw material oxide for soft ferrite used in Example 3.

FIG. 3 is a view showing a soft ferrite manufacturing process according to a conventional method.

FIG. 4 is a view showing a soft ferrite manufacturing process according to another conventional method.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 mixed chloride granulated powder 2 rotary kiln for first stage oxidation roasting 3 rotary kiln for second stage oxidation roasting 4 generated powder 5 rotary kiln for first stage oxidation roasting 6 powder generated at rotary kiln outlet for first stage oxidation roasting 7 Injection device 8 Injection roasting furnace 9 Generated oxide powder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 1/34 H01F 1/36

Claims (3)

(57) [Claims] Claims 1. An oxidative roasting of a mixed chloride of iron chloride, one or more of manganese, nickel and magnesium chloride and zinc chloride at a first temperature of 600 ° C or less, Thereafter, oxidizing and roasting is performed at a second temperature higher than the first temperature. 2. The method for producing a raw material oxide for soft ferrite according to claim 1, wherein the mixed chloride is a dried mixture powder or solid. 3. The method for producing a raw material oxide for soft ferrite according to claim 1, wherein the mixed chloride is a liquid dissolved in water or an organic solvent.