阅读说明：本技术 高磁导率锰锌铁氧体的制备方法 (Preparation method of manganese zinc ferrite with high magnetic conductivity ) 是由 刘涛 韩卫东 宋兴连 孔志强 高中国 解丽丽 于 2019-09-30 设计创作，主要内容包括：本申请提供的高磁导率锰锌铁氧体的制备方法中,以Fe<Sub>2</Sub>O<Sub>3</Sub>、ZnO及MnO为原料,通过一次球磨、预烧初步铁氧体化,然后经过二次球磨粉碎、造粒得到锰锌铁氧体颗粒,颗粒经成型、烧结处理后得到锰锌铁氧体粉料,其中将Fe<Sub>2</Sub>O<Sub>3</Sub>、ZnO及MnO混合于球磨机中且同时加入三乙醇胺或三乙醇胺硫酸酯,利用球磨机的机械力将大颗粒打开形成小颗粒,三乙醇胺或三乙醇胺硫酸酯作为分散剂可以有效地静电吸附在颗粒表面,防止颗粒二次团聚,使球磨得到的粒径更小,获得的锰锌铁氧体粉料的磁导率更高；本申请中木质素磺酸钙在后续烧结过程中分解为CaO,沉积在晶界处,可提高产品的电阻率,进而提高锰锌铁氧体粉料的磁导率。(in the preparation method of the manganese zinc ferrite with high magnetic permeability provided by the application, Fe is used 2 O 3 ZnO and MnO are used as raw materials, primary ferrite is subjected to primary ball milling and pre-sintering, then manganese-zinc ferrite particles are obtained through secondary ball milling and crushing and granulation, manganese-zinc ferrite powder is obtained after particles are subjected to molding and sintering treatment, wherein Fe is used as a raw material 2 O 3 ZnO and MnO are mixed in a ball mill, triethanolamine or triethanolamine sulfate is added at the same time, large particles are opened by using the mechanical force of the ball mill to form small particles, the triethanolamine or triethanolamine sulfate can be effectively and electrostatically adsorbed on the surfaces of the particles as a dispersing agent to prevent the particles from secondary agglomeration, so that the particle size obtained by ball milling is smaller, and the magnetic conductivity of the obtained manganese-zinc ferrite powder is higher; in the application, calcium lignosulfonate is decomposed into CaO in the subsequent sintering process and deposited at a crystal boundary, so that the resistivity of a product can be improved, and further the magnetic conductivity of manganese-zinc ferrite powder is improved.)

1. A preparation method of a manganese zinc ferrite with high magnetic permeability is characterized by comprising the following steps:

mixing Fe₂O₃putting the ZnO and MnO mixture into a ball mill, adding triethanolamine or triethanolamine sulfate into the ball mill, and performing ball milling to obtain primary ball-milled powder, wherein the average particle size of the primary ball-milled powder is 0.5-1.5 um;

Pre-burning the primary ball-milling powder to obtain flaky or spherical particles, wherein the pre-burning temperature is 750-950 ℃, and the pre-burning time is 1 h;

Carrying out ball milling on calcium lignosulfonate and the flaky or spherical particles to obtain secondary ball-milled powder, wherein the average particle size of the secondary ball-milled powder is 0.5-1.0 um;

mixing a ball milling medium, an additive, water, ethanol or acetone with the secondary ball milling powder, and sanding the mixture until the average particle size is less than 1.2um to obtain sanded granules;

circularly emulsifying the emulsifier and the sanding granules to obtain sanding slurry with the average granularity of 0.5-1.0 um;

Adding a binder or a plasticizer into the sand grinding slurry, and then performing spray granulation to obtain manganese-zinc ferrite particles with the particle size of 40-200 meshes;

pressing the manganese-zinc ferrite particles into a blank, and sintering the blank at the temperature of 1000-1250 ℃ for 2-4h to obtain the manganese-zinc ferrite with high magnetic permeability.

2. The method of claim 1, wherein the Fe is present in the form of Fe₂O₃Fe in the mixture of ZnO and MnO₂O₃: ZnO: the molar ratio of MnO is (51-55): (21-25): (20-28).

3. The method of claim 1, wherein the triethanolamine or the triethanolamine is selected from the group consisting ofSulfate of said Fe₂O₃0.05-0.5% of mixed material of ZnO and MnO, wherein the calcium lignosulfonate accounts for the Fe₂O₃And the mass portion of the mixture of ZnO and MnO is 0.05-0.5%.

4. The method of claim 1, wherein the ball milling media are steel balls made of bearing steel, and 21-25 steel balls are added per 1 g of the pulverized material.

5. The method of claim 1, wherein the additive comprises Bi₂O₃、MoO₃、Co₂o3 and TiO₂。

6. The method of claim 1, wherein the emulsifier comprises a hydroxyl terminated polysiloxane or an aliphatic chain-containing silane coupling agent.

7. The method as claimed in claim 1, wherein the permeability of the Mn-Zn ferrite is 10000-12000.

Technical Field

The application relates to the technical field of ferrite materials, in particular to a preparation method of a manganese zinc ferrite with high magnetic permeability.

background

The manganese-zinc ferrite is a soft magnetic material with a spinel structure, and is widely applied to the industries of communication, sensing, televisions and the like due to the physical and chemical properties of high magnetic conductivity, low loss and the like; with the rapid development of the electronic industry, higher and higher requirements are put on the performance of materials, such as high magnetic permeability.

The production process of the manganese-zinc ferrite with high magnetic permeability mainly comprises a dry method and a wet method, wherein the dry method has the advantages of simple process, good uniformity and the like, and is widely applied to the production process of manganese-zinc ferrite powder with high magnetic permeability; the production process of the dry manganese-zinc ferrite material mainly comprises the following steps: batching → mixing material → tabletting/pelletizing → presintering → crushing → sanding → mixing glue → granulating → molding → sintering, wherein, the reduction of the granularity of the material in the crushing and sanding process is the main way to improve the magnetic conductivity of the product, at present, the granularity of the material is usually reduced by two methods, the first method is to improve the sintering temperature to 1450 ℃ or prolong the sintering time; the second method is to extend the sanding time.

however, the first method has a problem that the uniformity of the fired product is poor due to an excessively high sintering temperature; the second method is easy to introduce excessive impurities in the sanding process, namely, the purity is reduced, and abnormal growth of products and the like are caused.

Disclosure of Invention

The application provides a preparation method of a manganese-zinc ferrite with high magnetic conductivity, which aims to reduce the particle size of materials on the premise of ensuring the uniformity and purity of products and further improve the magnetic conductivity.

In order to solve the technical problem, the embodiment of the application discloses the following technical scheme:

The application provides a preparation method of a manganese zinc ferrite with high magnetic permeability, which comprises the following steps:

mixing Fe₂O₃Putting the ZnO and MnO mixture into a ball mill, adding triethanolamine or triethanolamine sulfate into the ball mill, and performing ball milling to obtain primary ball-milled powder, wherein the average particle size of the primary ball-milled powder is 0.5-1.5 um;

Pre-burning the primary ball-milling powder to obtain flaky or spherical particles, wherein the pre-burning temperature is 750-950 ℃, and the pre-burning time is 1 h;

Carrying out ball milling on calcium lignosulfonate and the flaky or spherical particles to obtain secondary ball-milled powder, wherein the average particle size of the secondary ball-milled powder is 0.5-1.0 um;

mixing a ball milling medium, an additive, water, ethanol or acetone with the secondary ball milling powder, and sanding the mixture until the average particle size is less than 1.2um to obtain sanded granules;

Circularly emulsifying the emulsifier and the sanding granules to obtain sanding slurry with the average granularity of 0.5-1.0 um;

adding a binder or a plasticizer into the sand grinding slurry, and then performing spray granulation to obtain manganese-zinc ferrite particles with the particle size of 40-200 meshes;

pressing the manganese-zinc ferrite particles into a blank, and sintering the blank at the temperature of 1000-1250 ℃ for 2-4h to obtain the manganese-zinc ferrite with high magnetic permeability.

optionally, the Fe₂O₃fe in the mixture of ZnO and MnO₂O₃: ZnO: the molar ratio of MnO is (51-55): (21-25): (20-28).

optionally, the triethanolamine or triethanolamine sulfate accounts for the Fe₂O₃0.05-0.5% of mixed material of ZnO and MnO, wherein the calcium lignosulfonate accounts for the Fe₂O₃and the mass portion of the mixture of ZnO and MnO is 0.05-0.5%.

Optionally, the ball milling medium is steel balls made of bearing steel, and 21-25 steel balls are added to every 1 g of the crushed powder.

optionally, the additive comprises Bi₂O₃、MoO₃、Co₂O3 and TiO₂。

Optionally, the emulsifier comprises a hydroxyl-terminated polysiloxane or an aliphatic chain-containing silane coupling agent.

Optionally, the magnetic permeability of the manganese-zinc ferrite with high magnetic permeability is 10000-12000.

Compared with the prior art, the beneficial effect of this application is:

according to the technical scheme, in the preparation method of the manganese-zinc ferrite with high magnetic permeability, Fe is used₂O₃ZnO and MnO are used as raw materials, primary ferrite is realized through primary ball milling and presintering, manganese zinc ferrite particles are obtained through secondary ball milling and crushing and granulation, and high-permeability manganese zinc ferrite powder is obtained after the particles are subjected to molding and sintering treatment, wherein:

(1) In the application, Fe is mixed in the material mixing process₂O₃ZnO and MnO are mixed and then placed in a ball mill, triethanolamine or triethanolamine sulfate is added into the ball mill, large particles of materials are opened by the mechanical force of the ball mill to form independent small particles, the particle size of the particles is reduced, the triethanolamine or triethanolamine sulfate can be effectively and electrostatically adsorbed on the surfaces of the particles as a dispersing agent, the surface properties of the particles are changed to generate stronger repulsive force among the particles, secondary agglomeration of the particles is prevented, the particle size obtained by ball milling is smaller, and the magnetic conductivity of the obtained manganese-zinc ferrite powder is higher.

(2) According to the application, the calcium lignosulfonate can improve the grinding-aiding efficiency in the production process, is decomposed into CaO in the subsequent sintering process, is deposited at a crystal boundary, can improve the resistivity of a product, and further improves the magnetic conductivity of manganese-zinc ferrite powder.

(3) The triethanolamine or triethanolamine sulfate selected in the application can be decomposed and eliminated in the subsequent pre-sintering process, so that the introduction of impurities is avoided, and the purity of the product is ensured.

(4) After the application adopts the circulating sand grinding to the D90 granularity of less than 1.2um, 0.1 percent of hydroxyl-terminated polysiloxane or aliphatic chain-containing silane coupling agent is added for circulating emulsification so as to improve the granularity uniformity of the product, finally, the sand grinding slurry with the granularity of 0.5-1.0um and high dispersion concentration is obtained, and the uniformity of the product is ensured.

it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic flow chart of a preparation method of a manganese zinc ferrite with high magnetic permeability according to an embodiment of the present invention;

FIG. 2 is a graph showing the grain size results of the manganese-zinc ferrite with high magnetic permeability provided by the embodiment of the present invention;

fig. 3 is a graph illustrating the permeability results of the manganese-zinc-ferrite with high permeability provided by the embodiment of the invention.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic flow chart of a preparation method of a high permeability manganese-zinc ferrite according to an embodiment of the present invention. The following description of the embodiments is based on fig. 1.

As shown in fig. 1, the preparation method of the manganese zinc ferrite with high magnetic permeability provided by the present application comprises:

s110: mixing Fe₂O₃ZnO and MnO mixturePlacing the mixture into a ball mill, adding triethanolamine or triethanolamine sulfate into the ball mill, and performing ball milling to obtain primary ball-milled powder, wherein the average particle size of the primary ball-milled powder is 0.5-1.5 um.

Wherein, Fe₂O₃: ZnO: the molar ratio of MnO is (51-55): (21-25): (20-28), Fe₂O₃The content of the compound is more than 50mol percent in the formula, so that the magnetocrystalline anisotropy constant and the hysteresis expansion coefficient can be reduced, and the initial permeability of the material is improved; the weight portion of the triethanolamine or the triethanolamine sulfate is 0.05 to 0.5 percent.

In the application, the first ball milling utilizes the high-speed rotation of the steel balls in the ball mill to carry out Fe₂O₃ZnO and MnO particles are strongly impacted, ground and stirred to pulverize the powder into micron-sized particles, so that Fe is obtained₂O₃ZnO and MnO particles are plastically deformed, and the activation energy of elements is reduced, so that the components are mixed; the large particles of the material are opened by the mechanical force of the ball mill to form independent small particles, and the particle size of the particles becomes smaller.

In the application, triethanolamine or triethanolamine sulfate is selected as a dispersing agent, so that the triethanolamine or triethanolamine sulfate can be effectively and electrostatically adsorbed on the surfaces of particles, the surface properties of the particles are changed, stronger repulsive force is generated among the particles, secondary agglomeration of the particles is prevented, and the particle size obtained by ball milling is smaller; meanwhile, the grinding aid can improve the flowability of powder, is beneficial to improving the transmission efficiency of powder in the pelletizing or tabletting process, and can be decomposed and eliminated in the subsequent presintering process, so that the introduction of impurities is avoided, and the purity of the product is ensured; the impurities can affect the abnormal growth of ferrite grains, cause lattice defects and further affect the characteristics of products.

specifically, the granularity of the primary ball-milling powder is tested by a laser granularity meter, and the average granularity of the primary ball-milling powder is 0.5-1.5 um.

S120: and tabletting or pelletizing the primary ball-milling powder, and then pre-sintering to obtain flaky or spherical particles, wherein the pre-sintering temperature is 750-950 ℃, and the pre-sintering time is 1 h.

The pre-sintering in the application mainly aims to increase the iron oxidation degree of the split body after one-time ball milling, reduce the expansion rate of the product during subsequent sintering and prevent the product from deforming due to overlarge expansion; the pre-sintering temperature is 750-950 ℃, and when the pre-sintering temperature is too low, the pre-sintering effect is not shown; when the calcination temperature is too high, the activity of the powder is deteriorated, and therefore, an appropriate calcination temperature range is important for the permeability of the ferrite.

s130: and mixing calcium lignosulfonate with the flaky or spherical particles, placing the mixture in a ball mill, and performing secondary ball milling and crushing to obtain secondary ball milling powder, wherein the average particle size of the secondary ball milling powder is 0.5-1.0 um.

the powder after the presintering is easy to agglomerate, so that the return materials after the presintering are subjected to secondary ball milling and crushing; and the pre-firing does not burn all of the Fe₂O₃The mixture of ZnO and MnO particles all reacted to ferrite, so in this application the particles held inside the reaction layer were exposed by secondary ball milling and Fe was allowed to escape₂O₃ZnO and MnO particles are mutually contacted, which is beneficial to generating ferrite in the subsequent sintering process; meanwhile, the particles after presintering can be thinned by secondary ball milling and crushing, so that the particle size of the particles is reduced.

Wherein the mass part of the calcium lignosulphonate is 0.05-0.5%. Calcium lignosulfonate can regard as grinding aid on the one hand, improves the grinding aid efficiency in the production process, reduces the shake grinding time in order to save the charges of electricity, and on the other hand also can regard as the water-reducing agent, reduces the water yield that adds of later stage sanding in-process to reduce the energy consumption of spraying granulation in-process. Meanwhile, the grinding aid is decomposed into CaO in the subsequent sintering process, and the CaO is deposited at a crystal boundary, so that the resistivity of the product can be improved, and the magnetic conductivity of the product can be further improved.

S140: and mixing and sanding ball milling media, additives, water, ethanol or acetone with the secondary ball milling powder until the average particle size is less than 1.2um to obtain the sanded granules.

S150: and circularly emulsifying the emulsifying agent and the sanding granules to obtain sanding slurry with the average granularity of 0.5-1.0 um.

The ball milling medium is steel balls made of bearing steel, wherein 21-25 steel balls are added to every 1 g of the crushed powder.

in particular the additive comprises Bi₂O₃、MoO₃、Co₂O3 and TiO₂(ii) a In this application Bi₂O₃、MoO₃、Co₂O3 and TiO₂The purpose of adding is as follows: promote the solid-phase reaction and sintering degree of ferrite, thereby improving the electromagnetic properties of ferrite, particularly Bi₂O₃、MoO₃、Co₂O3 and TiO₂The low melting point can form a certain amount of liquid phase in the material during sintering, so that the densification degree of the material is increased, and the magnetic permeability of the material is improved.

The surface tension of water can be reduced to add 1 ~ 10% ethanol or acetone among the sanding process in this application to the boiling point of mixed solution has been reduced, thereby makes spray granulation process energy consumption reduce.

adopt the circulation system of sanding in this application, can obtain the powder material that particle size distribution is concentrated more, the result shows after using this method, the D50 of product can be reduced to 0.78um by original 1.0um, and the concentration of raw and other materials obtains obviously improving.

Specifically, the emulsifier in the present application includes hydroxyl-terminated polysiloxane or an aliphatic chain-containing silane coupling agent, and in this embodiment, 0.01 to 0.3% of hydroxyl-terminated polysiloxane or an aliphatic chain-containing silane coupling agent is added to improve the bonding strength between primary particles, reduce the amount of PVA used, and improve the overall strength of the molded product.

After the application adopts the circulating sand grinding to the D90 granularity of less than 1.2um, 0.1 percent of hydroxyl-terminated polysiloxane or aliphatic chain-containing silane coupling agent is added for circulating emulsification so as to improve the granularity uniformity of the product, finally, the sand grinding slurry with the granularity of 0.5-1.0um and high dispersion concentration is obtained, and the uniformity of the product is ensured.

s160: and adding a binder or a plasticizer into the sand grinding slurry, and then performing spray granulation to obtain manganese-zinc ferrite particles with the particle size of 40-200 meshes.

In the application, the sanding slurry is mixed with the adhesive and sieved into particles with a certain size, and the adhesive is added into the mixture during granulation to improve the plasticity and the associativity of the powder and the strength of the powder; in particular, the binder used in this application is polyvinyl alcohol, which decomposes into gases during sintering and is discharged from the blank.

S170: pressing the manganese-zinc ferrite particles into a blank, and sintering the blank at the temperature of 1000-1250 ℃ for 2-4h to obtain the manganese-zinc ferrite with high magnetic permeability.

Molding, namely, from ferrite powder to a ferrite blank; sintering is a key process in the improved preparation method of this embodiment, and the magnetic core obtained by sintering needs to achieve high density, less porosity, large crystal grain, and requires strict control of sintering temperature, the sintering temperature selected in this embodiment is 1000-.