Spherical manganous-manganic oxide based on spray pyrolysis as well as preparation method and application of spherical manganous-manganic oxide

Abstract

The invention provides spherical manganous-manganic oxide based on spray pyrolysis and a preparation method and application thereof, the preparation method comprises the following steps: mixing a manganese source, a solvent, a surfactant and a catalyst to obtain a precursor solution; and carrying out spray pyrolysis and post-treatment on the precursor solution to obtain the spherical manganous-manganic oxide based on spray pyrolysis, wherein the pyrolysis is sequentially and continuously performed in a first stage and a second stage, and the pyrolysis temperature of the second stage is higher than that of the first stage. According to the preparation method disclosed by the invention, by optimizing a precursor formula, pyrolysis conditions and a post-treatment process, the high-purity spherical manganous-manganic oxide can be prepared with high efficiency and low cost through spray pyrolysis.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials and relates to spherical manganese manganese oxide based on spray pyrolysis and a preparation method and application thereof. Background Art

[0002] As an important functional material, the purity, morphology, and particle size distribution of manganese tetraoxide directly impact its performance in downstream applications. Traditional methods for preparing manganese tetraoxide, including the metal manganese method, the manganese salt method, and the roasting method, suffer from drawbacks such as high raw material costs, high residual impurities, and complex processes. For example, the metal manganese method relies on electrolytic manganese flakes, resulting in high costs, while the manganese salt method easily introduces impurities such as sulfur and calcium, which can affect battery material performance.

[0003] In the prior art, for example, CN119370891A proposes using high-purity manganese hydroxide as raw material and directly generating manganese tetraoxide through ammonium salt-catalyzed hot air oxidation (25-90°C). The filtrate can be recycled to prepare the slurry, reducing raw material consumption. By controlling the reaction temperature and catalyst ratio, this technology achieves a manganese content of >70% and a product purity that meets battery-grade standards. For another example, CN119284961A addresses the problem of sulfur residue by adopting a two-step oxidation-reduction process. Raw materials with a sulfur content of ≥100ppm are oxidized in an air atmosphere at 350-600°C and then treated in a reducing gas at 250-550°C to reduce the sulfur content to ≤50ppm. At the same time, the crystal form is maintained stable. The resulting product has a high tap density and is suitable for high-energy-density battery positive electrode materials.

[0004] However, the above preparation methods still have problems such as complex process, high energy consumption and serious product agglomeration. In recent years, the spray pyrolysis method has attracted attention due to its advantages such as one-step powder formation and controllable particle morphology, but it still faces the following challenges: (1) Poor stability of the precursor solution: it can easily lead to component segregation during the spraying process, affecting the purity of the product. (2) Uneven particle morphology: low sphericity and poor dispersibility limit its application in battery materials. (3) Residual impurities: impurities such as sulfur and iron are difficult to remove, which reduces the electrochemical performance of the material.

[0005] Based on the above research, it is necessary to provide a method for preparing trimanganese tetraoxide, which can prepare high-purity spherical trimanganese tetraoxide efficiently and at low cost. Summary of the Invention

[0006] The present invention aims to provide a spherical manganese tetraoxide based on spray pyrolysis, a preparation method and application thereof. The preparation method can prepare high-purity spherical manganese tetraoxide by spray pyrolysis efficiently and at low cost by optimizing the precursor formula, pyrolysis conditions and post-treatment process.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis, the preparation method comprising the following steps:

[0009] (1) mixing a manganese source, a solvent, a surfactant, and a catalyst to obtain a precursor solution;

[0010] (2) spray pyrolysis and post-treatment of the precursor solution of step (1) to obtain the spherical manganese manganese oxide based on spray pyrolysis;

[0011] The pyrolysis is divided into a first stage and a second stage which are carried out in sequence, and the temperature of the pyrolysis in the second stage is higher than that of the pyrolysis in the first stage.

[0012] The present invention regulates the viscosity of the solution and the dispersibility of the particles by adding a surfactant and a catalyst to the precursor solution, wherein the surfactant can reduce the surface tension of the solution, improve the atomization uniformity during spray pyrolysis, and prevent metal ion segregation. The precursor solution is then subjected to spray pyrolysis, and the pyrolysis is carried out in two stages. The low-temperature stage quickly evaporates the solvent and decomposes organic matter to form porous precursor particles, thereby avoiding particle melting and agglomeration. The high-temperature stage promotes the crystal transformation of manganese oxide, optimizes crystal development, improves product purity, and generates high-purity spherical Mn3O4 particles. Therefore, the product obtained by the present invention has uniform crystal particle size and can be directly used for the synthesis of lithium battery positive electrode materials or electronic materials. The spray pyrolysis is powdered in one step without the need for multiple precipitation and calcination steps, which can reduce energy consumption and control costs. The raw material utilization rate is greater than 95%, the filtrate can be recycled, and no wastewater or waste gas is discharged. The pyrolysis tail gas is absorbed by a three-stage countercurrent alkali solution (such as a NaOH solution) and then used for the dissolution production of the front-stage material. The waste liquid in the post-treatment is treated to meet the "Comprehensive Wastewater Discharge Standard" (GB 8978-1996) or relevant local / industry standards and can be discharged directly.

[0013] Preferably, the surfactant in step (1) includes a first surfactant and a second surfactant, wherein the first surfactant includes any one of EDTA-2Na, IDS or PASP or a combination of at least two thereof, and the second surfactant includes any one of polyethylene glycol, a dendritic polymer (such as PAMAM, a polyamide-amine dendritic polymer) or PFS-b-P2VP (a block copolymer composed of polyferrocenylsilane and poly-2-vinylpyridine) or a combination of at least two thereof.

[0014] The present invention adopts the synergistic effect of composite surfactants, wherein the first surfactant such as EDTA-2Na can chelate metal ions to prevent metal ion segregation, and the second surfactant such as polyethylene glycol can reduce surface tension and improve atomization uniformity.

[0015] Preferably, the mass ratio of the first surfactant to the second surfactant is 1:(1.5-3), for example, it can be 1:1.5, 1:2, 1:2.5 or 1:3, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, in the precursor solution of step (1), the content of the first surfactant is 0.3-1wt%, for example, it can be 0.3wt%, 0.5wt%, 0.7wt%, 0.9wt% or 1wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, in the precursor solution of step (1), the content of the second surfactant is 0.8-1.8wt%, for example, it can be 0.8wt%, 1.0wt%, 1.2wt%, 1.4wt%, 1.6wt% or 1.8wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, in the precursor solution of step (1), the concentration of manganese ions is 0.5-2.0 mol / L, for example, 0.5 mol / L, 1 mol / L, 1.5 mol / L or 2.0 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, the pH of the precursor solution in step (1) is 2.0-7.0, for example, 3.0, 4.0, 5.0, 6.0 or 7.0, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] The present invention adjusts the pH to 3.0-7.0, which can prevent premature hydrolysis of manganese ions.

[0021] Preferably, the catalyst content in the precursor solution of step (1) is 0.35-0.6 mol / L, for example, it can be 0.35 mol / L, 0.45 mol / L, 0.55 mol / L or 0.6 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the manganese source in step (1) includes manganese sulfate and / or manganese chloride.

[0023] Preferably, the catalyst in step (1) comprises ammonium chloride.

[0024] Preferably, the solvent in step (1) comprises deionized water.

[0025] Preferably, the atomization pressure of the spray pyrolysis in step (2) is 0.2-0.5 MPa, for example, it can be 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa, and the liquid inlet rate is 10-30 mL / min, for example, it can be 10 mL / min, 15 mL / min, 20 mL / min, 25 mL / min or 30 mL / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the temperature of the first stage pyrolysis in step (2) is 300-400°C, for example, 300°C, 350°C or 400°C, and the time is 2-8 seconds, for example, 2 seconds, 4 seconds, 6 seconds or 8 seconds, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] The temperature of the first stage pyrolysis and the temperature of the second stage pyrolysis of the present invention are coordinated with each other. If the temperature of the first stage pyrolysis is too low, the solvent will not evaporate completely, and the particles will stick together and agglomerate severely. If the temperature of the first stage pyrolysis is too high, the particle surface will sinter prematurely, and the internal gas will not be able to escape, forming a hollow / cracked structure.

[0028] Preferably, the temperature of the second stage pyrolysis in step (2) is 600-1000°C (preferably 800-1000°C), for example, it can be 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C or 1000°C, and the time is 5-15 seconds, for example, it can be 5 seconds, 7 seconds, 9 seconds, 11 seconds, 13 seconds or 15 seconds, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] The temperature of the first stage pyrolysis and the temperature of the second stage pyrolysis of the present invention are coordinated with each other. If the temperature of the second stage pyrolysis is too low, the crystal transformation is incomplete and the MnO2 impurity phase remains. If the temperature of the second stage pyrolysis is too high, excessive oxidation will occur to generate MnO, and the particles will melt and deform.

[0030] Preferably, the pyrolysis atmosphere in step (2) comprises air and nitrogen.

[0031] During the spray pyrolysis process of the present invention, a mixed gas of air and nitrogen is introduced to suppress excessive oxidation to generate MnO2.

[0032] Preferably, the volume ratio of air to nitrogen is 1:(0.5-2), for example, 1:0.5, 1:1, 1:1.5 or 1:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the post-processing in step (2) includes shaping.

[0034] Preferably, the shaping method includes fluidized bed air flow mill shaping.

[0035] Preferably, the pressure of the fluidized bed airflow mill is 0.8-1.2 MPa, for example, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa or 1.2 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, pickling is performed after the shaping, and the pickling solution used for pickling includes dilute nitric acid with a concentration of 0.1-0.5 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the acid washing is performed until the sulfur content in the product is ≤50 ppm, for example, 50 ppm, 40 ppm, 30 ppm, 20 ppm or 10 ppm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] In a second aspect, the present invention provides a spherical manganese trimanganese tetraoxide based on spray pyrolysis, wherein the spherical manganese trimanganese tetraoxide based on spray pyrolysis is prepared by adopting the preparation method as described in the first aspect.

[0039] Preferably, the particle size D50 of the spherical manganese tetraoxide based on spray pyrolysis is 0.1-10 μm, for example, 0.5 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm or 10 μm, the particle size D90 is ≤ 15 μm, for example, 15 μm, 14 μm, 13 μm or 12 μm, and the tap density is ≥ 2.4 g / cm 3 , for example, it can be 2.4g / cm 3 , 2.5g / cm 3 , 2.6g / cm 3 , 2.7g / cm 3 or 2.8g / cm 3 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0040] In a third aspect, the present invention provides an application of the spherical manganese manganese oxide based on spray pyrolysis as described in the second aspect, wherein the application includes use in preparing lithium manganate positive electrode materials or use in preparing manganese zinc ferrite materials.

[0041] The lithium manganate positive electrode material prepared from the spherical manganese tetraoxide of the present invention has an initial discharge capacity of ≥125 mAh / g at a 0.5C rate and a capacity retention rate of >90% after 500 cycles. The magnetic permeability of the manganese-zinc ferrite prepared from the spherical manganese tetraoxide is increased by more than 15%, and the high-frequency loss is reduced by more than 20%.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention regulates the viscosity of the solution and the dispersibility of the particles by adding a surfactant and a catalyst to the precursor solution, wherein the surfactant can reduce the surface tension of the solution, improve the atomization uniformity during spray pyrolysis, and prevent metal ion segregation. The precursor solution is then subjected to spray pyrolysis, and the pyrolysis is carried out in two stages. The low-temperature stage quickly evaporates the solvent and decomposes organic matter to form porous precursor particles, thereby avoiding particle melting and agglomeration. The high-temperature stage promotes the crystal transformation of manganese oxide, optimizes crystal development, improves product purity, and generates high-purity spherical Mn3O4 particles. Therefore, the product obtained by the present invention has uniform crystal particle size and can be directly used for the synthesis of lithium battery positive electrode materials or electronic materials. The spray pyrolysis is powdered in one step without the need for multiple precipitation and calcination steps, which can reduce energy consumption and control costs. The raw material utilization rate is greater than 95%, the filtrate can be recycled, and no wastewater or waste gas is discharged. The pyrolysis tail gas is used for the dissolution production of the front-stage materials after undergoing three-stage countercurrent absorption, and the waste liquid in the post-treatment can be directly discharged after meeting the treatment standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the SEM image of the spherical manganese tetraoxide based on spray pyrolysis obtained in Example 1 of the present invention. Figure 1 It can be seen that the product is regular spherical and the particle size distribution is uniform. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] Example 1

[0047] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis, the preparation method comprising the following steps:

[0048] (1) adding EDTA-2Na, polyethylene glycol, and ammonium chloride to a 1.5 mol / L manganese chloride solution, mixing the mixture, and adjusting the pH to 4 to obtain a precursor solution;

[0049] In the precursor solution, the content of EDTA-2Na is 0.5 wt %, the content of polyethylene glycol is 1.0 wt %, and the content of ammonium chloride is 0.6 mol / L;

[0050] (2) spray pyrolysis of the precursor solution of step (1) to obtain spray pyrolysis particles, wherein the atomization pressure is 0.3 MPa, the liquid feeding rate is 20 mL / min, and the pyrolysis is carried out in a first stage and a second stage in sequence, the temperature of the first stage pyrolysis is 350° C., the time is 3 seconds, the temperature of the second stage pyrolysis is 850° C., the time is 6 seconds, and the pyrolysis atmosphere is air and nitrogen with a volume ratio of 1:1;

[0051] (3) The spray pyrolysis particles of step (2) were subjected to fluidized bed air flow milling at a pressure of 1 MPa, and then acid washed with dilute nitric acid at a concentration of 0.1 mol / L to obtain spherical manganese tetraoxide with an S content of <25 ppm. The SEM image of the spherical manganese tetraoxide is shown in FIG. Figure 1 As shown by Figure 1 It can be seen that the sphericity of manganese tetraoxide is high and the particle size distribution is uniform.

[0052] Example 2

[0053] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis, the preparation method comprising the following steps:

[0054] (1) adding EDTA-2Na, polyethylene glycol, and ammonium chloride to a 1.5 mol / L manganese sulfate solution, mixing the mixture, and adjusting the pH to 4.0 to obtain a precursor solution;

[0055] In the precursor solution, the content of EDTA-2Na is 0.6 wt %, the content of polyethylene glycol is 1.2 wt %, and the content of ammonium chloride is 0.5 mol / L;

[0056] (2) spray pyrolysis of the precursor solution of step (1) to obtain spray pyrolysis particles, wherein the atomization pressure is 0.3 MPa, the liquid feeding rate is 20 mL / min, and the pyrolysis is carried out in a first stage and a second stage in sequence, the temperature of the first stage pyrolysis is 400° C., the time is 5 seconds, the temperature of the second stage pyrolysis is 950° C., the time is 6 seconds, and the pyrolysis atmosphere is air and nitrogen with a volume ratio of 1:1;

[0057] (3) The spray pyrolysis particles in step (2) are subjected to fluidized bed air flow milling at a pressure of 1 MPa, and are pickled with dilute nitric acid at a concentration of 0.3 mol / L to obtain spherical manganese tetraoxide with an S content of <20 ppm.

[0058] Example 3

[0059] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis, the preparation method comprising the following steps:

[0060] (1) adding EDTA-2Na, polyethylene glycol, and ammonium chloride to a 2.0 mol / L manganese chloride solution, mixing the mixture, and adjusting the pH to 3.0 to obtain a precursor solution;

[0061] In the precursor solution, the content of EDTA-2Na is 0.3 wt %, the content of polyethylene glycol is 0.8 wt %, and the content of ammonium chloride is 0.6 mol / L;

[0062] (2) spray pyrolysis of the precursor solution of step (1) to obtain spray pyrolysis particles, wherein the atomization pressure is 0.5 MPa, the liquid feeding rate is 10 mL / min, and the pyrolysis is carried out in a first stage and a second stage in sequence, the temperature of the first stage pyrolysis is 300° C., the time is 3 seconds, the temperature of the second stage pyrolysis is 800° C., the time is 8 seconds, and the pyrolysis atmosphere is air and nitrogen with a volume ratio of 1:2;

[0063] (3) The spray pyrolysis particles of step (2) are subjected to fluidized bed air flow milling at a pressure of 1.2 MPa, and are pickled with dilute nitric acid at a concentration of 0.5 mol / L to obtain spherical manganese tetraoxide with an S content of <20 ppm.

[0064] Example 4

[0065] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis, the preparation method comprising the following steps:

[0066] (1) adding EDTA-2Na, polyethylene glycol, and ammonium chloride to a 0.5 mol / L manganese chloride solution, mixing the mixture, and adjusting the pH to 6.0 to obtain a precursor solution;

[0067] In the precursor solution, the content of EDTA-2Na is 1 wt %, the content of polyethylene glycol is 1.8 wt %, and the content of ammonium chloride is 0.35 mol / L;

[0068] (2) spray pyrolysis of the precursor solution of step (1) to obtain spray pyrolysis particles, wherein the atomization pressure is 0.2 MPa, the liquid feeding rate is 30 mL / min, and the pyrolysis is carried out in a first stage and a second stage in sequence, the temperature of the first stage pyrolysis is 400° C., the time is 4 seconds, the temperature of the second stage pyrolysis is 1000° C., the time is 8 seconds, and the pyrolysis atmosphere is air and nitrogen with a volume ratio of 1:0.5;

[0069] (3) The spray pyrolysis particles of step (2) are subjected to fluidized bed air flow milling at a pressure of 0.8 MPa, and are pickled with dilute nitric acid at a concentration of 0.1 mol / L to obtain spherical manganese tetraoxide with an S content of <25 ppm.

[0070] Example 5

[0071] This embodiment provides a preparation method of spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1, except that EDTA-2Na is replaced by polyethylene glycol so that the precursor solution contains only polyethylene glycol as a surfactant.

[0072] Example 6

[0073] This embodiment provides a preparation method of spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1, except that the mass of polyethylene glycol is replaced by EDTA-2Na so that the precursor solution contains only EDTA-2Na as a surfactant.

[0074] Example 7

[0075] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1 except that the temperature of the first stage pyrolysis in step (2) is 200°C.

[0076] Example 8

[0077] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1 except that the temperature of the first stage pyrolysis in step (2) is 500°C.

[0078] Example 9

[0079] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1 except that the temperature of the second stage pyrolysis in step (2) is 600°C.

[0080] Example 10

[0081] This embodiment provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as that of Example 1 except that the temperature of the second stage pyrolysis in step (2) is 1200°C.

[0082] Comparative Example 1

[0083] This comparative example provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as Example 1 except that EDTA-2Na and polyethylene glycol are not added in step (1).

[0084] Comparative Example 2

[0085] This comparative example provides a method for preparing spherical manganese manganese oxide based on spray pyrolysis. The preparation method is the same as Example 1 except that step (2) does not perform the first stage pyrolysis but directly performs the second stage pyrolysis.

[0086] The particle size D50, tap density and Mn content of the spherical manganese tetraoxide obtained in the above examples and comparative examples are shown in Table 1:

[0087] Table 1

[0088] Particle size D50 (μm) <![CDATA[Tap density (g / cm 3 )]]> Mn content (wt%) Example 1 3.52 2.51 71.5 Example 2 5.05 2.45 71.2 Example 3 3.8 2.48 71.6 Example 4 5.2 2.42 71.0 Example 5 4.25 2.46 71.3 Example 6 4.6 2.44 71.4 Example 7 5.8 2.38 69.26 Example 8 3.2 2.53 71.7 Example 9 2.9 2.35 65.39 Example 10 9.5 2.58 75.45 Comparative Example 1 18.62 2.26 70.8 Comparative Example 2 8.1 2.28 70.6

[0089] Note: Particle size D50 is measured by laser particle size analyzer; tap density is measured according to GB / T 5162-2021 / ISO3953:2011; Mn content is determined by inductively coupled plasma atomic emission spectrometry (ICP-OES).

[0090] From Table 1 we can see that:

[0091] It can be seen from Example 1 and Comparative Example 1 that the present invention is beneficial to improving the uniformity of atomization and preventing metal ion segregation by adding a surfactant to the precursor solution, thereby facilitating obtaining spherical manganese tetraoxide with high purity and high tap density; it can be seen from Example 1 and Comparative Example 2 that the present invention adopts a staged pyrolysis process, the low temperature stage can avoid particle melting and agglomeration, and the high temperature stage can optimize the crystal development and improve the product purity; it can be seen from Example 1 and Examples 5-6 that the present invention adopts the synergistic effect of a composite surfactant, EDTA-2Na chelates metal ions to prevent segregation, and polyethylene glycol reduces surface tension, thereby improving the uniformity of atomization, which is beneficial to obtaining spherical manganese tetraoxide with high purity and high tap density; it can be seen from Examples 1 and Examples 7-10 that the present invention preferably cooperates the pyrolysis temperature in the first stage and the pyrolysis temperature in the second stage, thereby improving the effect of the staged pyrolysis process and improving the purity of the product.

[0092] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that 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 fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing spherical manganese manganese oxide based on spray pyrolysis, characterized in that: The preparation method comprises the following steps: (1) mixing a manganese source, a solvent, a surfactant, and a catalyst to obtain a precursor solution; (2) spray pyrolysis and post-treatment of the precursor solution of step (1) to obtain the spherical manganese manganese oxide based on spray pyrolysis; The pyrolysis is divided into a first stage and a second stage which are carried out in sequence, and the temperature of the pyrolysis in the second stage is higher than that of the pyrolysis in the first stage.

2. The preparation method according to claim 1, characterized in that The surfactant in step (1) includes a first surfactant and a second surfactant, wherein the first surfactant includes any one of EDTA-2Na, IDS, or PASP, or a combination of at least two thereof, and the second surfactant includes any one of polyethylene glycol, a dendrimer, or PFS-b-P2VP, or a combination of at least two thereof; Preferably, the mass ratio of the first surfactant to the second surfactant is 1:(1.5-3); Preferably, in the precursor solution of step (1), the content of the first surfactant is 0.3-1 wt%; Preferably, in the precursor solution of step (1), the content of the second surfactant is 0.8-1.8 wt %.

3. The preparation method according to claim 1 or 2, characterized in that In the precursor solution of step (1), the concentration of manganese ions is 0.5-2.0 mol / L; Preferably, the pH of the precursor solution in step (1) is 2.0-7.0; Preferably, the content of the catalyst in the precursor solution in step (1) is 0.35-0.6 mol / L.

4. The preparation method according to any one of claims 1 to 3, characterized in that The manganese source in step (1) includes manganese sulfate and / or manganese chloride; Preferably, the catalyst in step (1) comprises ammonium chloride; Preferably, the solvent in step (1) comprises deionized water.

5. The preparation method according to any one of claims 1 to 4, characterized in that The atomization pressure of the spray pyrolysis in step (2) is 0.2-0.5 MPa, and the liquid feeding rate is 10-30 mL / min; Preferably, the temperature of the first stage pyrolysis in step (2) is 300-400° C. and the time is 2-8 seconds; Preferably, the temperature of the second stage pyrolysis in step (2) is 600-1000° C. and the time is 5-15 seconds.

6. The preparation method according to any one of claims 1 to 5, characterized in that The pyrolysis atmosphere in step (2) includes air and nitrogen; Preferably, the volume ratio of air to nitrogen is 1:(0.5-2).

7. The preparation method according to any one of claims 1 to 6, characterized in that The post-processing in step (2) includes shaping; Preferably, the shaping method includes fluidized bed air flow mill shaping; Preferably, the pressure of the fluidized bed jet mill is 0.8-1.2 MPa; Preferably, pickling is performed after the shaping; Preferably, the acid washing is carried out until the sulfur content in the product is ≤50 ppm.

8. A spherical manganese tetraoxide based on spray pyrolysis, characterized in that: The spherical manganese manganese oxide based on spray pyrolysis is prepared by adopting the preparation method according to any one of claims 1 to 7.

9. The spherical manganese manganese oxide based on spray pyrolysis according to claim 8, characterized in that: The spherical manganese tetraoxide based on spray pyrolysis has a particle size D50 of 0.1-10 μm, a particle size D90 ≤ 15 μm, and a tap density ≥ 2.4 g / cm 3 ; Preferably, the Mn content of the spherical trimanganese tetraoxide produced by spray pyrolysis is ≥71 wt%.

10. A use of the spherical manganese manganese oxide based on spray pyrolysis according to claim 8 or 9, characterized in that: The application includes preparing lithium manganese oxide positive electrode materials or preparing manganese zinc ferrite materials.

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