Preparation method and product of manganese tetraoxide material for soft magnetic materials with high fluidity

Abstract

The present invention discloses a preparation method and product of manganese tetraoxide material for high-fluidity soft magnetic use, relating to the technical field of manganese tetraoxide preparation. To solve the problem that the manganese tetraoxide products obtained by the existing production methods are difficult to simultaneously meet the requirements of good fluidity and easy grindability; the present invention includes dissolving a manganese salt in water to obtain a manganese salt solution; adding a complexing agent to the manganese salt solution to obtain a manganese salt mixed solution; preparing an alkali solution; adding a bottom liquid to a reaction vessel; at different temperatures, adding the manganese salt mixed solution and the alkali solution to the reaction vessel in three times, stirring and ventilating during the process, filtering and washing with water several times after each feeding is completed, and then adding water to re-prepare into a manganese slurry and adding it to the reaction vessel for the next complexation precipitation; spray-drying the manganese slurry of the third time to obtain a manganese tetraoxide powder material; the method steps of the present invention are simple and easy to operate, and the obtained manganese tetraoxide product has a three-layer capsule structure and has the advantages of good fluidity and high easy grindability.

Description

Technical Field

[0001] The present invention relates to the technical field of manganese tetraoxide preparation, and specifically to a preparation method and product of manganese tetraoxide material for high-fluidity soft magnetic use. Background Art

[0002] Manganese tetraoxide materials have been widely used in the field of soft magnetic manganese-zinc ferrites for many years. In addition, they are also used in small amounts in fields such as thermistors, pigments, and catalysts. There are various industrial preparation methods for it, but they can be classified into roasting method and oxidation method according to the reaction nature and process characteristics. The roasting method is to heat metal manganese or manganese oxides, hydroxides, sulfates, sulfites, carbonates, nitrates, and permanganates in air or oxygen to 1000 °C for roasting, and then obtain manganese tetraoxide through cooling and pulverization. The oxidation method is further divided into two process routes: metal manganese suspension oxidation method and manganese sulfate solution precipitation oxidation method. Among them, the metal manganese suspension oxidation method is to crush electrolytic metal manganese sheets into a certain particle size by dry or wet methods, add pure water to prepare a suspension, then add a catalytic agent, and introduce air or oxygen to carry out a catalytic oxidation reaction to prepare manganese tetraoxide; the manganese sulfate solution precipitation oxidation method uses primary manganese ore as raw material, after sulfuric acid leaching and chemical impurity removal, under alkaline conditions, air is used to oxidize divalent manganese in the leaching solution of manganese ore, manganese sulfate solution, to manganese tetraoxide.

[0003] With the advancement of electrification and electrification, the market demand for soft magnetic ferrites will further expand in the future. With the gradual deepening of domestic industrial upgrading, negative pressure pipeline transportation is mostly used for powder conveying, which can effectively solve problems such as powder being polluted by the environment and leakage in the production site. However, pipeline transportation has high requirements for the fluidity of the powder. Most of the current downstream application fields of manganese tetraoxide require both good fluidity and good grindability of the powder.

[0004] Through research, the smaller the particle size of the powder, the greater the molecular attraction and electrostatic attraction, and it is easy to form close packing between particles, resulting in worse fluidity of the powder; the smaller the contact area between powder particles, the better the fluidity, and the smaller the contact area of particles closer to regular spherical particles; the greater the mass-volume ratio of the product, the worse the grindability of the material; that is, in order to meet the fluidity, it is only necessary to agglomerate into a spherical shape. However, due to the relatively high tapped density and compacted density of the agglomerated spherical particles, it is difficult to meet the requirements of grindability at the same time; and if a loose product with a small mass-volume ratio that is easy to grind is to be made, it cannot meet the requirements of fluidity. This has brought great troubles to the production and operation of enterprises. Therefore, there is an urgent need for a preparation method and product of manganese tetraoxide material for high-fluidity soft magnetic use to solve this problem. Summary of the Invention

[0005] The object of the present invention is to provide a preparation method and product of manganese tetraoxide material for high-fluidity soft magnetic, so as to solve the problem that the manganese tetraoxide products obtained by the existing production methods are difficult to simultaneously meet the requirements of good fluidity and easy grindability.

[0006] To achieve the above object, the present invention provides the following technical solution: A preparation method of manganese tetraoxide material for high-fluidity soft magnetic, comprising the following specific steps:

[0007] (1) Dissolve manganese salt in water to obtain a manganese salt solution;

[0008] (2) Add a complexing agent to the manganese salt solution to obtain a manganese salt mixed solution;

[0009] (3) Prepare an alkali solution;

[0010] (4) Add a bottom liquid to the reaction vessel;

[0011] (5) At 70 - 90 °C, add a part of the manganese salt mixed solution and a part of the alkali solution to the reaction vessel at a feeding rate of 1 - 30 ml / min, while maintaining a stirring speed of 500 - 800 rpm and an air flow rate of 100 - 1000 ml / min during the process;

[0012] (6) After the feeding is completed, filter the slurry obtained in (5), wash it with water several times, and then add water to re-prepare it into a manganese slurry;

[0013] (7) At 60 - 75 °C, add the manganese slurry obtained in (6) to the reaction vessel, add a part of the manganese salt mixed solution and a part of the alkali solution to the reaction vessel at a feeding rate of 1 - 20 ml / min, while maintaining a stirring speed of 400 - 600 rpm and an air flow rate of 100 - 500 ml / min during the process;

[0014] (8) After the feeding is completed, filter the slurry obtained in (7), wash it with water several times, and then add water to re-prepare it into a manganese slurry;

[0015] (9) At 50 - 70 °C, add the manganese slurry obtained in (8) to the reaction vessel, add the remaining manganese salt mixed solution and the remaining alkali solution to the reaction vessel at a feeding rate of 0.1 - 5 ml / min, while maintaining a stirring speed of 200 - 400 rpm and an air flow rate of 50 - 100 ml / min during the process;

[0016] (10) After the feeding is completed, filter the slurry obtained in (7), wash it with water several times, and then add water to re-prepare it into a manganese slurry, and perform spray drying to obtain a manganese tetraoxide powder material.

[0017] Preferably, in step (1), the manganese salt is one or more of manganese nitrate, manganese acetate, manganese sulfate, and manganese chloride. The concentration of the manganese salt solution is 0.2 - 2 mol / L, and the volume is 1 - 10 L.

[0018] Preferably, in step (2), the complexing agent is one or more of sodium hexadecyl sulfonate (CTAB), disodium ethylenediaminetetraacetate (EDTA), tetrasodium iminodisuccinate (IDS), and sodium citrate (SSC). The addition amount of the complexing agent is 1 g - 10 g.

[0019] Preferably, in step (3), the alkali solution is one or two of sodium hydroxide solution and ammonia water. The concentration of the alkali solution is 0.4 - 4 mol / L, and the volume is 1 - 10 L.

[0020] Preferably, in step (4), the base solution is one or several of water, ammonium chloride solution, and ammonium acetate solution. The volume of the base solution is 50 - 150 ml.

[0021] Preferably, in step (5), both the manganese salt mixed solution and the alkali solution are 1 / 4 of their respective total amounts.

[0022] Preferably, in step (6), the concentration of the re-prepared manganese slurry is 80 g / L.

[0023] Preferably, in step (7), both the manganese salt mixed solution and the alkali solution are 1 / 2 of their respective total amounts.

[0024] Preferably, in step (8), the concentration of the re-prepared manganese slurry is 30 g / L.

[0025] Preferably, in step (9), both the manganese salt mixed solution and the alkali solution are 1 / 4 of their respective total amounts.

[0026] Preferably, in step (10), the concentration of the re-prepared manganese slurry is 300 - 500 g / L.

[0027] Preferably, in steps (5), (7), and (9), the feeding speed ratio of the manganese salt mixed solution to the alkali solution is 1:2.2.

[0028] Preferably, in steps (6), (8), and (10), the washing water amount is 5 - 10 times the volume of the remaining solid after filtration.

[0029] Preferably, the reaction vessel uses the small-scale test device in Patent CN202223210483.7.

[0030] Another technical solution provided by the present invention: A manganese tetraoxide material for high-fluidity soft magnetic materials prepared by the above method.

[0031] Preferably, the above manganese tetraoxide material is a three-layer capsule structure, and the outermost layer is spherical, D50 is 3.5 - 4.5 μm, and the angle of repose is 26 ± 1°.

[0032] Preferably, take 100 g of the above-mentioned manganese tetroxide material, add 100 g of 5 mm zirconia grinding balls, and grind for 30 min at 280 r / min in a planetary mill with the direction changed every 6 min. After grinding, the median particle size of the material is 0.1 - 0.6 μm.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1. The preparation method of the manganese tetroxide material for high-fluidity soft magnetic use has simple and easy-to-operate steps. Using manganese salt as the raw material, through the process of fractional complexation precipitation oxidation method, key technical parameters such as the feeding method, the addition amount of complexing agent, the addition timing, the feeding speed, and the reaction temperature are controlled to prepare a manganese tetroxide material with a three-layer capsule structure. This method can control physical properties such as the BET, particle size distribution, and primary particle size of manganese tetroxide within the required range, and effectively control the morphological characteristics and easy-to-grind properties of the prepared manganese tetroxide product.

[0035] 2. The preparation method and product of the manganese tetroxide material for high-fluidity soft magnetic use obtain a core with smaller particles and a smaller mass-to-volume ratio in the first complexation precipitation, a transition layer with a medium mass-to-volume ratio in the second complexation precipitation, and a shell with larger particles and a larger mass-to-volume ratio in the third complexation precipitation. And after each complexation, it is washed with water and repulped to ensure that the intermediate products are fully dispersed after each stage of operation. This capsule structure makes the manganese tetroxide material have an outer layer with good fluidity and an inner layer and core that are easy to grind. The resistance during the conveying process is much smaller than that of the prior art, and it will not affect the normal operation of the conveying equipment, and can reduce the losses caused by production stoppage for dredging and equipment maintenance and repair; while during the grinding process, although the outer layer has an easy-to-grind degree similar to that of other existing methods, after grinding off the outer layer, the inner layer has a high easy-to-grind degree and is overall more easy to grind, which can indirectly reduce the downstream processing cost.

[0036] 3. The manganese tetroxide material for high-fluidity soft magnetic use has the advantages of uniform particle size distribution, high consistency, good activity, high easy-to-grind property, and good fluidity, and can simultaneously meet the requirements of downstream application fields for the fluidity and easy-to-grind property of the manganese tetroxide material. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 SEM diagram of the manganese tetroxide prepared in Example 1.

[0038] Figure 2 SEM diagram of the manganese tetroxide prepared in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0039] A preparation method of manganese ferrite material for high-fluidity soft magnetic materials, comprising the following specific steps:

[0040] (1) Dissolve manganese salt in water to obtain a manganese salt solution. The manganese salt can be one or more of manganese nitrate, manganese acetate, manganese sulfate, and manganese chloride. The concentration of the manganese salt solution should be 0.2-2 mol / L. For reference, the volume of the manganese salt solution can be 1-10 L;

[0041] (2) Add a complexing agent to the manganese salt solution to obtain a manganese salt mixed solution. The complexing agent can be selected from one or more of sodium hexadecyl sulfonate (CTAB), disodium ethylenediaminetetraacetate (EDTA), tetrasodium iminodisuccinate (IDS), and sodium citrate (SSC). For reference, the addition amount of the complexing agent should be 1 g-10 g;

[0042] (3) Prepare an alkali solution, which can be sodium hydroxide solution and / or ammonia water, and its concentration can be 0.4-4 mol / L. For reference, the volume of the alkali solution can be 1-10 L;

[0043] (4) Add a bottom liquid to the reaction vessel. The bottom liquid can be one or several of water, ammonium chloride solution, and ammonium acetate solution. For reference, the volume of the bottom liquid can be 50-150 ml;

[0044] (5) At 70-90 °C, add a part of the manganese salt mixed solution and a part of the alkali solution to the reaction vessel at a feeding rate of 1-30 ml / min, and maintain a stirring speed of 500-800 rpm and a ventilation volume of 100-1000 ml / min during the process. For reference, both the manganese salt mixed solution and the alkali solution are added 1 / 4 of their respective total amounts;

[0045] (6) After the feeding is completed, filter the slurry obtained in (5) and wash it with water several times, and then add water to re-prepare a manganese slurry, and its concentration can be 80 g / L;

[0046] (7) At 60-75 °C, add the manganese slurry obtained in (6) to the reaction vessel, and add a part of the manganese salt mixed solution and a part of the alkali solution to the reaction vessel at a feeding rate of 1-20 ml / min, and maintain a stirring speed of 400-600 rpm and a ventilation volume of 100-500 ml / min during the process. For reference, both the manganese salt mixed solution and the alkali solution are added 1 / 2 of their respective total amounts;

[0047] (8) After the feeding is completed, filter the slurry obtained in (7) and wash it with water several times, and then add water to re-prepare a manganese slurry, and its concentration can be 30 g / L;

[0048] (9) At 50 - 70 °C, add the manganese slurry obtained in (8) to the reaction vessel, and add the remaining manganese salt mixed solution and the remaining alkali solution to the reaction vessel at a feeding rate of 0.1 - 5 ml / min. During the process, maintain a stirring speed of 200 - 400 rpm and an air flow rate of 50 - 100 ml / min. For reference, both the manganese salt mixed solution and the alkali solution are added at 1 / 4 of their total amounts.

[0049] (10) After the feeding is completed, filter the slurry obtained in (7), wash it with water several times, and then add water to re - prepare it into a manganese slurry with a concentration of 300 - 500 g / L, and perform spray drying to obtain manganese tetraoxide powder material.

[0050] In addition, in the above steps (5), (7), and (9), the feeding rate ratio of the manganese salt mixed solution to the alkali solution is preferably 1:2.2; in steps (6), (8), and (10), the washing water amount is preferably 5 - 10 times the volume of the remaining solid after filtration.

[0051] For better ventilation effect, the reaction vessel can preferably adopt the small - scale test device in Patent CN202223210483.7.

[0052] The manganese tetraoxide material prepared by the above method is a three - layer capsule structure, and its outermost layer is close to spherical, with D 50 being 3.5 - 4.5 μm, the angle of repose being 25° - 27°, and the fluidity being excellent; take 100 g of the above - mentioned manganese tetraoxide material, add 100 g of 5 - mm zirconia grinding balls, grind with a planetary mill at 280 r / min and change the direction every 6 min for 30 min. After grinding, the median particle size of the material is 0.1 - 0.6 μm, and the grindability is good.

[0053] Example 1:

[0054] (1) Dissolve manganese sulfate salt in 1 L of water to obtain a 2 - mol / L manganese salt solution.

[0055] (2) Add 2 g of CTAB to the manganese salt solution obtained in (1) to obtain a manganese sulfate salt mixed solution.

[0056] (3) Prepare a 2 - mol / L sodium hydroxide solution.

[0057] (4) Place 100 ml of bottom water in a 5 - L reaction vessel.

[0058] (5) At 90 °C, add 250 ml of the manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 20 ml / min, and at the same time add 250 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 44 ml / min. During the process, maintain a stirring speed of 800 rpm and an air flow rate of 1000 ml / min.

[0059] After the feeding is completed, filter the slurry obtained in (5), wash it three times with 200 ml of water, and then prepare a 80 g / L manganese slurry again.

[0060] (7) At 70 °C, add the manganese slurry obtained in (6) to the reaction vessel. Add the 500 ml manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 8 ml / min, and at the same time add the 500 ml sodium hydroxide solution in (3) to the reactor at a feeding rate of 17.6 ml / min. During the process, keep the stirring speed at 500 rpm and the ventilation rate at 400 ml / min.

[0061] (8) After the feeding is completed, filter the slurry obtained in (7), wash it three times with 400 ml of water, and then prepare a 30 g / L manganese slurry again.

[0062] (9) At 50 °C, add the manganese slurry obtained in (8) to the reaction vessel. Add the 250 ml manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 2 ml / min, and at the same time add the 250 ml sodium hydroxide solution in (3) to the reactor at a feeding rate of 4.4 ml / min. During the process, keep the stirring speed at 200 rpm and the ventilation rate at 50 ml / min.

[0063] (10) After the feeding is completed, filter the slurry obtained in (9), wash it three times with 1600 ml of water, and then prepare a 350 g / L manganese slurry again, and perform spray drying to obtain a manganese tetroxide powder material with a three-layer capsule structure and a nearly spherical outermost layer. The SEM image is shown in Figure 1 .

[0064] Example 2:

[0065] (1) Dissolve manganese chloride salt in 1 L of water to obtain a 2 mol / L manganese salt solution.

[0066] (2) Add 2 g of SSC to the manganese salt solution obtained in (1) to obtain a manganese chloride salt mixed solution.

[0067] (3) Prepare a 2 mol / L sodium hydroxide solution.

[0068] (4) Place 100 ml of 0.1 M ammonium acetate solution in a 5 L reaction vessel.

[0069] (5) At 90 °C, add 250 ml of the manganese chloride salt mixed solution in (2) to the reactor at a feeding rate of 20 ml / min. At the same time, add 250 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 44 ml / min. During the process, maintain the stirring speed at 800 rpm and the ventilation volume at 1000 ml / min;

[0070] (6) After the feeding is completed, filter the slurry obtained in (5) and wash it 3 times with 200 ml of water. Then, re-prepare a manganese slurry with a concentration of 80 g / L;

[0071] (7) At 70 °C, add the manganese slurry obtained in (6) to the reaction vessel. Add 500 ml of the manganese chloride salt mixed solution in (2) to the reactor at a feeding rate of 10 ml / min. At the same time, add 500 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 22 ml / min. During the process, maintain the stirring speed at 500 rpm and the ventilation volume at 400 ml / min;

[0072] (8) After the feeding is completed, filter the slurry obtained in (7) and wash it 3 times with 400 ml of water. Then, re-prepare a manganese slurry with a concentration of 30 g / L;

[0073] (9) At 50 °C, add the manganese slurry obtained in (8) to the reaction vessel. Add 250 ml of the manganese chloride salt mixed solution in (2) to the reactor at a feeding rate of 2 ml / min. At the same time, add 250 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 4.4 ml / min. During the process, maintain the stirring speed at 200 rpm and the ventilation volume at 50 ml / min;

[0074] (10) After the feeding is completed, filter the slurry obtained in (9), wash it 3 times with 1600 ml of water, and then re-prepare a manganese slurry with a concentration of 350 g / L. Perform spray drying to obtain a manganese tetraoxide powder material with a three-layer capsule structure and a nearly spherical outermost layer.

[0075] Example 3:

[0076] (1) Dissolve manganese acetate salt in 1 L of water to obtain a manganese salt solution with a concentration of 2 mol / L;

[0077] (2) Add 2 g of IDS to the manganese salt solution obtained in (1) to obtain a manganese acetate salt mixed solution;

[0078] (3) Prepare a 2 mol / L sodium hydroxide solution;

[0079] (4) Prepare 100 ml of a 0.1 M ammonium acetate solution and place it in a 5 L reaction vessel;

[0080] (5) At 90 °C, add 250 ml of the manganese acetate salt mixed solution in (2) to the reactor at a feeding rate of 25 ml / min, and at the same time add 250 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 55 ml / min. During the process, keep the stirring speed at 800 rpm and the ventilation volume at 1000 ml / min;

[0081] (6) After the feeding is completed, filter the slurry obtained in (5) and wash it 3 times with 200 ml of water, and then re-prepare a manganese slurry with a concentration of 80 g / L;

[0082] (7) At 70 °C, add the manganese slurry obtained in (6) to the reaction vessel, add 500 ml of the manganese acetate salt mixed solution in (2) to the reactor at a feeding rate of 15 ml / min, and at the same time add 500 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 33 ml / min. During the process, keep the stirring speed at 500 rpm and the ventilation volume at 400 ml / min;

[0083] (8) After the feeding is completed, filter the slurry obtained in (7) and wash it 3 times with 400 ml of water, and then re-prepare a manganese slurry with a concentration of 30 g / L;

[0084] (9) At 50 °C, add the manganese slurry obtained in (8) to the reaction vessel, add 250 ml of the manganese acetate salt mixed solution in (2) to the reactor at a feeding rate of 2 ml / min, and at the same time add 250 ml of the sodium hydroxide solution in (3) to the reactor at a feeding rate of 4.4 ml / min. During the process, keep the stirring speed at 200 rpm and the ventilation volume at 50 ml / min;

[0085] (10) After the feeding is completed, filter the slurry obtained in (9), wash it 3 times with 1600 ml of water, and then re-prepare a manganese slurry with a concentration of 400 g / L, and perform spray drying to obtain a manganese tetraoxide powder material with a three-layer capsule structure and the outermost layer close to a spherical shape.

[0086] Example 4:

[0087] (1) Dissolve manganese sulfate salt in 1 L of water to obtain a manganese salt solution with a concentration of 2 mol / L;

[0088] (2) Add 1 g of IDS and 1 g of CTAB to the manganese salt solution obtained in (1) to obtain a manganese sulfate salt mixed solution;

[0089] (3) Prepare a 4 mol / L ammonia water solution;

[0090] (4) Prepare 100 ml of 0.1 M ammonium acetate solution + 100 ml of 0.1 M ammonium chloride solution and place it in a 5 L reaction vessel;

[0091] (5) At 90 °C, add 250 ml of the manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 25 ml / min. At the same time, add 250 ml of the ammonia water solution in (3) to the reactor at a feeding rate of 55 ml / min. During the process, keep the stirring speed at 800 rpm and the ventilation volume at 1000 ml / min;

[0092] (6) After the feeding is completed, filter the slurry obtained in (5) and wash it 3 times with 200 ml of water. Then, prepare a manganese slurry with a concentration of 80 g / L again;

[0093] (7) At 70 °C, add the manganese slurry obtained in (6) to the reaction vessel. Add 500 ml of the manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 15 ml / min. At the same time, add 500 ml of the ammonia water solution in (3) to the reactor at a feeding rate of 33 ml / min. During the process, keep the stirring speed at 500 rpm and the ventilation volume at 400 ml / min;

[0094] (8) After the feeding is completed, filter the slurry obtained in (7) and wash it 3 times with 400 ml of water. Then, prepare a manganese slurry with a concentration of 30 g / L again;

[0095] (9) At 50 °C, add the manganese slurry obtained in (8) to the reaction vessel. Add 250 ml of the manganese sulfate salt mixed solution in (2) to the reactor at a feeding rate of 2 ml / min. At the same time, add 250 ml of the ammonia water solution in (3) to the reactor at a feeding rate of 4.4 ml / min. During the process, keep the stirring speed at 200 rpm and the ventilation volume at 50 ml / min;

[0096] (10) After the feeding is completed, filter the slurry obtained in (9), wash it 3 times with 1600 ml of water, then prepare a manganese slurry with a concentration of 400 g / L again, and perform spray drying to obtain a manganese tetraoxide powder material with a three-layer capsule structure and a nearly spherical outermost layer.

[0097] Comparative Example 1:

[0098] (1) Take 1 ton of electrolytic metal manganese sheets and add them to a horizontal ball mill for wet ball milling for 80 min to obtain a manganese slurry with a particle size less than 80 mesh;

[0099] (2) First, add 1 m 3 to a 10 m 3Deionized water, and then 30 Kg of ammonium chloride was added to the reaction kettle as a catalyst. The prepared manganese slurry was added to the reaction kettle, and then deionized water was added to the reaction kettle to dilute the manganese slurry to obtain a reaction slurry with a manganese mass percentage concentration of 30%. The stirring impeller in the reaction kettle was started, and the frequency converter was adjusted to set the rotation speed of the stirring impeller at 200 r / min; at the same time, air was introduced into the reaction kettle, and the air flow rate was adjusted to 100 m 3 / h,

[0100] (3) The reaction continued until the pH value of the slurry dropped to 6.5, and then it ended to obtain a manganese tetraoxide slurry;

[0101] (4) The manganese tetraoxide slurry was put into a blender, and then deionized water was added and stirred for 30 minutes. Then, it was washed and filtered by vacuum filtration, and finally dried to obtain a manganese tetraoxide product.

[0102] The SEM image of the manganese tetraoxide product prepared in Comparative Example 1 is shown in Figure 2 .

[0103] The physical and chemical indexes of the manganese tetraoxide products obtained in Examples 1 to 4 and Comparative Example 1 were tested. The test methods and the obtained results of each index are shown in Table 1 below:

[0104] Table 1 Physical and chemical indexes of manganese tetraoxide products in examples and comparative examples

[0105]

[0106] Note: The evaluation method of the grindability of manganese tetraoxide is to take 100 g of the material, add 100 g of 5 mm zirconia grinding balls, grind the material at 280 r / min in a planetary mill, change the direction every 6 minutes for 30 minutes, and rate it according to the median particle size of the ground material. The specific rating standard is: [0.1, 0.3] μm is Grade 1, (0.3, 0.6] μm is Grade 2, (0.6, 0.9] μm is Grade 3, (0.9, 1.2] μm is Grade 4, (1.2, 1.5] μm is Grade 5, (1.5, 1.8] μm is Grade 6.

[0107] The results show that the manganese tetraoxide products prepared by the method of the present invention in Examples 1 to 4 have a small specific surface area, large particle size, high bulk density, and have the advantages of uniform particle size distribution, high consistency, good activity, high grindability, and good fluidity.

[0108] The above are only the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

[0109] Where the present invention is not described in detail, it is common knowledge to those skilled in the art of this technology.

Claims

1. A preparation method of manganese ferrite material for high-fluidity soft magnetism, characterized in that, It includes the following specific steps: (1) Dissolve the manganese salt in water to obtain a manganese salt solution; (2) Add a complexing agent to the manganese salt solution to obtain a manganese salt mixed solution; (3) Prepare an alkali solution; (4) Add a bottom liquid to the reaction vessel; (5) At 70 - 90 °C, add a part of the manganese salt mixed solution and a part of the alkali solution into the reaction vessel at a feeding rate of 1 - 30 mL / min, while maintaining a stirring speed of 500 - 800 rpm and an air flow rate of 100 - 1000 mL / min during the process; (6) After the feeding is completed, filter the slurry obtained in (5) and wash it with water several times, and then add water to re - prepare it into a manganese slurry; (7) At 60 - 75 °C, add the manganese slurry obtained in (6) into the reaction vessel, and add a part of the manganese salt mixed solution and a part of the alkali solution into the reaction vessel at a feeding rate of 1 - 20 mL / min, while maintaining a stirring speed of 400 - 600 rpm and an air flow rate of 100 - 500 mL / min during the process; (8) After the feeding is completed, filter the slurry obtained in (7) and wash it with water several times, and then add water to re - prepare it into a manganese slurry; (9) At 50 - 70 °C, add the manganese slurry obtained in (8) into the reaction vessel, and add the remaining manganese salt mixed solution and the remaining alkali solution into the reaction vessel at a feeding rate of 0.1 - 5 mL / min, while maintaining a stirring speed of 200 - 400 rpm and an air flow rate of 50 - 100 mL / min during the process; (10) After the feeding is completed, filter the slurry obtained in (7), wash it with water several times, and then add water to re - prepare it into a manganese slurry, and perform spray drying to obtain a manganese tetraoxide powder material.

2. The preparation method of a manganese tetraoxide material for high - fluidity soft magnetic use according to claim 1, characterized in that: In step (1), the manganese salt is one or more of manganese nitrate, manganese acetate, manganese sulfate, and manganese chloride, the concentration of the manganese salt solution is 0.2 - 2 mol / L, and the volume is 1 - 10 L; In step (2), the complexing agent is one or more of sodium hexadecyl sulfonate, disodium ethylenediaminetetraacetate, tetrasodium iminodisuccinate, and sodium citrate, and the addition amount of the complexing agent is 1 g - 10 g; In step (3), the alkali solution is one or two of sodium hydroxide solution and ammonia water, the concentration of the alkali solution is 0.4 - 4 mol / L, and the volume is 1 - 10 L; In step (4), the bottom liquid is one or several of water, ammonium chloride solution, and ammonium acetate solution, and the volume of the bottom liquid is 50 - 150 mL.

3. The preparation method of a manganese tetroxide material for high-fluidity soft magnetism according to claim 1, characterized in that: In step (5), both the manganese salt mixed solution and the alkali solution are 1 / 4 of their respective total amounts; in step (6), the concentration of the re - prepared manganese slurry is 80 g / L.

4. The preparation method of a manganese tetroxide material for high-fluidity soft magnetism according to claim 1, characterized in that: In step (7), both the manganese salt mixed solution and the alkali solution are 1 / 2 of their respective total amounts; in step (8), the concentration of the re - prepared manganese slurry is 30 g / L.

5. The preparation method of a manganese tetraoxide material for high-fluidity soft magnetic use according to claim 1, characterized in that: In step (9), both the manganese salt mixed solution and the alkali solution are 1 / 4 of their respective total amounts; in step (10), the concentration of the re - prepared manganese slurry is 300 - 500 g / L.

6. The preparation method of a manganese tetroxide material for high-fluidity soft magnetism according to claim 1, characterized in that: In the steps (5), (7), and (9), the feeding speed ratio of the manganese salt mixed solution to the alkali solution is 1:2.

2.

7. The preparation method of a manganese tetraoxide material for high-fluidity soft magnetic use according to claim 1, wherein: The washing water amount in the steps (6), (8), and (10) is 5 - 10 times the volume of the remaining solid after filtration.

8. A manganese tetroxide material for high-fluidity soft magnetism prepared by the method according to any one of claims 1 to 7, characterized in that: The manganese tetraoxide material is a three-layer capsule structure, and the outermost layer is spherical. D 50 is 3.5 - 4.5 μm, and the angle of repose is 26 ± 1°.

9. The manganese tetraoxide material for high-fluidity soft magnetic according to claim 8, wherein: For the manganese tetraoxide material, take 100 g, add 100 g of 5 mm zirconia grinding balls, grind with a planetary mill at 280 r / min, change the direction of abrasives every 6 min for 30 min, and the median particle size of the ground material is 0.1 - 0.6 μm.

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