Nano zirconium oxide powder as well as preparation method, preparation device and application thereof

Abstract

The invention discloses nano zirconium oxide powder as well as a preparation method, a preparation device and application thereof. The preparation method comprises the following steps: dissolving metal oxide powder of which the particle size D90 is less than 50 microns in a solvent to form slurry; pressurizing, stirring and dispersing the slurry to form pre-dispersed slurry, and sanding the pre-dispersed slurry; conveying the slurry subjected to sanding treatment into flame combustion equipment to realize doping, and completing drying to obtain a doped nano zirconium oxide product. According to the method, the technological process is simple, the prepared product is small in particle size, uniform in particle size and high in purity, the element doping in the obtained doped nano-zirconia product is uniform, and the product obtained through the method can serve as an electrolyte film raw material of a solid oxide fuel cell.

Description

Technical Field

[0001] This invention relates to the fields of nanopowder preparation technology and solid oxide fuel cell technology, and particularly to nano-zirconia powder, its preparation method, preparation apparatus and applications. Background Technology

[0002] Nanoparticles, due to their quantum size effect, surface effect, and high reactivity, exhibit a series of unique optical, magnetic, electrical, and thermal functional properties, as well as excellent mechanical properties, making them promising for applications in catalysts, heat exchange materials, high-performance targets, ceramic materials, lubricants, and 3D printing. Among these, high-purity ultrafine zirconia powder (ZrO2) is a crucial raw material for high-performance ceramics, with a wide range of applications. It is indispensable in the ceramics industry and other sectors such as metallurgy, electronics, machinery, aerospace, and daily chemicals, especially in functional ceramics, such as oxygen sensors, various piezoelectric ceramic components, high-temperature heating elements, and high-temperature solid-state batteries.

[0003] Chinese patent CN103466648B describes a self-propagating metallurgical method for preparing ultrafine powders. This method involves mixing magnesium powder with oxides and a reducing agent, ball-milling the mixture to a particle size of less than 0.5 μm, pressing it into a billet, and then placing it in a self-propagating furnace to initiate a self-propagating reaction. The resulting billet needs to be crushed, and impurities are removed by leaching with hydrochloric acid to obtain a solid phase wash. Finally, the powder is dried to remove moisture, yielding tungsten powder with a purity greater than 99% and a particle size of less than 1 μm, or zirconium powder with a particle size of less than 400 nm. This method has a long process flow, results in low product purity, and the magnesium powder is highly reactive, making it prone to explosion if stored or used improperly.

[0004] Chinese patent application CN117003282A discloses a nano-zirconia powder and its preparation method, which includes multiple steps such as precipitation, centrifugation, spray drying, sintering, sand milling, and re-centrifugation and drying. This method suffers from numerous steps and complex processes. Furthermore, suitable large-scale equipment is difficult to find for centrifugation after sand milling, and secondary agglomeration of particles is prone to occur during re-drying.

[0005] Chinese patent application CN1040932A discloses a method for preparing ultrafine powder by ultrasonic atomization. This method uses chloride or nitrate as raw materials and prepares oxide powder through ultrasonic spray pyrolysis. However, the hydrogen chloride generated by using chloride as raw material can easily corrode the equipment, requiring high-performance equipment. Furthermore, chloride ions easily adhere to the surface of the powder after spray pyrolysis, resulting in low product purity. Using nitrate as raw material will generate a large amount of nitrogen oxides, which can easily cause environmental pollution.

[0006] Zirconia powder is widely used in solid oxide fuel cells (SOFCs). For better subsequent slurry casting, industry standards require that the zirconia powder used in SOFC films not only have a nano-micron particle size (D90 less than 1 μm), but also a specific surface area of ​​8–15 m². 2 / g, and high purity is required, with a purity greater than 99.9%. Summary of the Invention

[0007] The purpose of this invention is to provide a method and apparatus for preparing nano-zirconia powder with small particle size, high purity, short process flow, and the ability to achieve continuous online production, as well as the prepared nano-zirconia powder and its application in solid oxide fuel cells.

[0008] The above objective can be achieved through the following technical solutions:

[0009] According to one aspect of the present invention, a method for preparing nano-zirconia powder is provided, comprising:

[0010] S1: Dissolve metal oxide powder with a particle size D90 less than 50 μm in a solvent in a certain proportion to form a slurry; wherein, the solvent is one of anhydrous ethanol and methanol; the metal oxide powder is zirconium oxide and oxides of doped elements.

[0011] S2: The mud is pressurized, stirred, and dispersed to form a pre-dispersed slurry;

[0012] S3: The pre-dispersed slurry is subjected to sand milling treatment;

[0013] S4: The slurry after sand milling is transported to a flame combustion device to achieve doping and complete drying to obtain doped nano-zirconia products.

[0014] Preferably, in the metal oxide powder, the molar ratio of the oxide of the dopant element to zirconium oxide is (8-12):(92-88).

[0015] Preferably, the oxide of the doping element is one or more of scandium oxide, cerium oxide, ytterbium oxide, aluminum oxide, and yttrium oxide.

[0016] Preferably, the solid-liquid ratio of the metal oxide powder to the solvent is 1:5 to 10.

[0017] Preferably, when dispersing under pressure, the pressure is 0.2 MPa to 10 MPa and the stirring time is 10 minutes to 60 minutes.

[0018] Preferably, a grinding machine is used for sand milling, with a rotation speed of 1300 r / min to 2500 r / min and a sand milling time of 20 minutes to 160 minutes.

[0019] Preferably, the flame temperature in the flame combustion device is 1000℃~1600℃.

[0020] Preferably, the doped nano-zirconia product is cubic phase, with a particle size D50 less than 0.3 μm, D90 less than 0.7 μm, a purity greater than 99.9%, and a specific surface area of ​​8 m². 2 / g~15m 2 / g.

[0021] Preferably, step S4 specifically includes: conveying the slurry after sand milling from one side of the flame combustion device to the flame combustion device, spraying the filtered combustion-supporting gas from the bottom of the flame combustion device into the flame combustion device, so that the airflow carries the liquid slurry into the flame combustion area at high speed, and using the high-temperature flame to dope zirconium oxide with the oxide of the doping element and complete the drying, thereby obtaining the doped nano zirconium oxide product.

[0022] More preferably, step S4 further includes: shearing and crushing the particles falling to the lower port of the flame combustion device;

[0023] More preferably, step S4 further includes: performing gas-solid separation on the dried product discharged from the top of the flame combustion device.

[0024] More preferably, after the gas-solid separation is completed and the particles are collected, the small particles are collected in a secondary stage.

[0025] According to one aspect of the present invention, an apparatus for preparing nano-zirconia powder is provided, comprising: a flame combustion device for receiving a slurry after sand milling to achieve doping and complete drying, thereby obtaining a doped nano-zirconia product;

[0026] The flame combustion device has a combustion aid inlet at the bottom, a slurry inlet on the side wall, and a stirring and crushing device inside. The stirring and crushing device is located at the lower port and is lower than the slurry inlet. The flame combustion device has an outlet at the top. A filter is also provided at the combustion aid inlet.

[0027] Preferably, the apparatus for preparing nano-zirconia powder further includes: a feeding device connected to the slurry inlet of the flame combustion equipment, used to meter and continuously convey the slurry after sand milling to the flame combustion equipment. More preferably, the feeding device is a liquid pump;

[0028] Preferably, the outlet of the flame combustion device is connected to a cyclone separator. Further, the outlet of the cyclone separator is connected to a collection device, which is used for secondary collection of small particles after the cyclone separation is complete.

[0029] More preferably, the collecting device is also connected to a negative pressure device.

[0030] Furthermore, the collecting device uses a high-temperature resistant sintered plate.

[0031] Preferably, the apparatus for preparing the nano-zirconia powder further includes:

[0032] A mud preparation apparatus is used to dissolve metal oxide powder with a particle size D90 of less than 50 μm in a solvent in a certain proportion to form mud; wherein, the solvent is one of anhydrous ethanol and methanol; and the metal oxide powder is zirconium oxide and oxides of doped elements.

[0033] A pressure mixing and dispersing device is used to pressurize and disperse mud to form a pre-dispersed slurry;

[0034] A sand milling device is used to sand mill pre-dispersed slurry.

[0035] According to one aspect of the present invention, a nano-zirconia powder is provided, which is a doped nano-zirconia product prepared by the method for preparing the nano-zirconia powder described above.

[0036] According to one aspect of the present invention, an application of nano-zirconia powder in a solid oxide fuel cell is provided, wherein the nano-zirconia powder is used as a raw material for an electrolyte film, and the nano-zirconia powder is prepared by the method described above.

[0037] Beneficial effects: According to one embodiment of the present invention, metal oxide powder is dissolved in a solvent to form a slurry, which is then dispersed by pressure stirring, followed by sand milling. Finally, the slurry after sand milling is transported to a flame combustion device for processing to achieve doping and drying, thereby realizing the preparation of doped nano-zirconia products. The process is simple, can realize online continuous production, and the prepared product has small particle size, uniform particle size, and high purity. The element doping in the doped nano-zirconia product is uniform.

[0038] Compared with the prior art, some embodiments of the present invention also have the following advantages:

[0039] 1) The preparation process adopts the process of "preparing mud - pressurized stirring and dispersion - sand milling - flame combustion treatment". The process flow is simple, saves many steps, and can realize online continuous production.

[0040] 2) Anhydrous ethanol or methanol is used as a solvent. Since anhydrous ethanol has a good dispersing effect, using anhydrous ethanol as a solvent makes it less likely for the particles after sand milling to agglomerate. At the same time, anhydrous ethanol / methanol is used as fuel. After the flame is burned, no additional heat source is needed. The rapidly ejected high-temperature flame can achieve doping of zirconium oxide and doping elements, while the solvent evaporates rapidly, achieving a drying effect instantly, and the particles are less likely to agglomerate.

[0041] 3) It directly uses metal oxides as raw materials, eliminating the need for chloride salts, nitrate salts, etc., thus requiring less equipment and avoiding corrosion problems.

[0042] 4) The particles falling to the lower end of the flame combustion equipment are stirred, sheared, and crushed by the stirring and crushing device, which further prevents the particles from agglomerating.

[0043] 5) By using pressure mixing and dispersion to disperse the mud, the slurry is well mixed and dispersed, thus easily obtaining powder with uniform particle size distribution through sand milling. Further optimization of the pressure mixing conditions can further improve the dispersion effect.

[0044] 6) By installing a filter at the combustion aid inlet of the flame combustion equipment, the combustion aid, such as combustion-supporting gas, is filtered and then injected into the flame combustion equipment, reducing the impurity content of the gas entering the equipment, thereby controlling the purity of the product.

[0045] 7) The prepared zirconia product is cubic in phase, meeting the requirements for electrolyte film raw materials in solid oxide fuel cells. The product particle size D50 is less than 0.3 μm, D90 is less than 0.7 μm, the product purity is greater than 99.9%, and the specific surface area is 8–15 m². 2 / g. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of a flame combustion device according to an embodiment of the present invention.

[0047] Figure 2 This is the XRD pattern of the scandium oxide-doped zirconium oxide powder prepared in Example 1 of the present invention.

[0048] Figure 3 This is the XRD pattern of the product prepared in Comparative Example 2 of this invention. Detailed Implementation

[0049] The technical solution of the present invention will be clearly and completely described below with reference to embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] In one embodiment of the present invention, an apparatus for preparing nano-zirconia powder including a flame combustion device is provided. (Reference) Figure 1 As shown, the flame combustion device has a combustion aid inlet at the bottom, a slurry inlet on the side wall, and an outlet at the top. An internal stirring and crushing device is also installed, positioned at the lower port below the slurry inlet. This flame combustion device receives the slurry after sand milling, and the rapidly ejected high-temperature flame allows for the doping of zirconium oxide with oxides of doping elements, resulting in doped nano-zirconia products. Simultaneously, it achieves instantaneous drying, preventing particle agglomeration.

[0051] Of course, this device can also be used to prepare undoped nano-zirconia products. By utilizing the high-temperature flame rapidly ejected from the flame combustion device, drying can be completed quickly and instantly, making it difficult for particles to agglomerate.

[0052] In a preferred embodiment, a filter is installed at the combustion accelerator inlet, and the filtered combustion accelerator is sprayed into the equipment to reduce the impurity content of the incoming gas, thereby controlling the product purity. Specifically, the filtered combustion accelerator gas is sprayed into the equipment, and further, it is one or more of filtered oxygen, air, or oxygen-enriched air to improve the product purity. The oxygen volume concentration in the oxygen-enriched air is 25% to 42%. Furthermore, the combustion accelerator gas is rapidly sprayed into the flame combustion equipment by a blower connected to the combustion accelerator inlet, so that the airflow carries the liquid slurry at high speed into the flame combustion area, forming a vortex and simultaneously exerting a shearing effect. The flame combustion area is located at the upper part of the flame combustion equipment. Figure 1 The region shown by the middle triangle.

[0053] like Figure 1 As shown, a cyclone separator is also connected to the outlet of the flame combustion device to perform gas-solid separation of the flame combustion products and complete the primary collection; a collection device is connected to the outlet of the cyclone separator to perform secondary collection of the small particles after gas-solid separation.

[0054] The collection device is also connected to a negative pressure device, which can provide a negative pressure environment for the collection device and the cyclone separator for negative pressure collection. The negative pressure collection helps the products in the flame combustion equipment to enter the cyclone separator from the upper outlet for collection, and finer particles enter the collection device for secondary collection.

[0055] Preferably, the collecting device uses a high-temperature resistant sintered plate. Specifically, when gas carrying small particles enters the collecting device, the powder particles are trapped on the polytetrafluoroethylene (PTFE) coating on the surface of the sintered plate, while the clean gas is discharged through the outlet of the sintered plate.

[0056] In a preferred embodiment, the slurry inlet of the flame combustion device is further connected to a feeding device for metering and continuously conveying the milled slurry into the flame combustion device. Preferably, the feeding device is a liquid pump.

[0057] The process of using the flame combustion equipment: The combustion-supporting gas is injected from the bottom of the flame combustion equipment. The slurry after sand milling is metered into the slurry inlet on one side by a liquid pump. The airflow carries the liquid slurry into the flame combustion area at high speed, forming a vortex and shearing action. The combustion-supporting agent inlet is equipped with a filter, and a stirring and crushing device is installed at the lower port to shear and crush large particles that fall from the flame combustion area. Small particles are carried into the cyclone separator by the high-speed airflow and the negative pressure at the tail for gas-solid separation. Even finer particles enter the collection device for further collection.

[0058] In an optional embodiment, the apparatus for preparing nano-zirconia powder may further include: a slurry preparation device, a pressure stirring and dispersing device, and a sand milling device. The slurry preparation device dissolves metal oxide powder in a solvent at a certain ratio to prepare a slurry. The pressure stirring and dispersing device pressurizes and disperses the slurry to form a pre-dispersed slurry. The sand milling device then mills the pre-dispersed slurry after pressurization and dispersion.

[0059] The nano-zirconia powder preparation device first prepares the metal oxide powder into a slurry, then pressurizes and disperses it before sand milling. This process is more conducive to the slurry entering the subsequent flame combustion equipment for doping, resulting in a product with small particle size, uniform particle size, high purity, and uniform doping elements.

[0060] In one embodiment of the present invention, a method for preparing nano-zirconia powder is provided, comprising the following steps:

[0061] S1: Metal oxide powder with a particle size D90 less than 50 μm is dissolved in a solvent in a certain proportion to form a mixed slurry. The metal oxide powder is zirconium oxide and oxides of doped elements.

[0062] S2: The mixed mud is pressurized, stirred and dispersed to form a pre-dispersed slurry.

[0063] S3: The pre-dispersed slurry is subjected to sand milling.

[0064] S4: The slurry after sand milling is transported to a flame combustion device to achieve doping and complete drying to obtain doped nano-zirconia products, namely doped zirconia nanoparticles.

[0065] The product prepared by the above method has small particle size, high purity, and uniform elemental doping. The process is short and can achieve continuous online production. Furthermore, step S1 of this application directly uses metal oxides as raw materials, eliminating the need for chlorides, nitrates, etc., thus requiring less sophisticated equipment and avoiding corrosion issues.

[0066] In a preferred embodiment, the molar ratio of the oxide of the dopant element to zirconium oxide is (8-12):(92-88) to obtain a cubic zirconium oxide product with good electrical conductivity, which can be better applied in solid oxide fuel cells. Doping introduces elements such as scandium, cerium, ytterbium, aluminum, or yttrium into zirconium oxide, improving its performance. The oxide of the dopant element can be, for example, one or more of scandium oxide, cerium oxide, ytterbium oxide, aluminum oxide, and yttrium oxide.

[0067] The doped zirconia nanoparticles obtained in this application are cubic phase, with a particle size D50 of less than 0.3 μm, a D90 of less than 0.7 μm, a purity greater than 99.9%, and a specific surface area of ​​8–15 m². 2 / g. The doped nano-zirconia product can be used as a raw material for electrolyte films in solid oxide fuel cells.

[0068] The solvent is either anhydrous ethanol or methanol. Anhydrous ethanol / methanol can be used as fuel, and no additional heat source is needed after combustion. The rapidly ejected high-temperature flame causes the solvent to evaporate quickly. In addition, the rapidly ejected high-temperature flame can also be used to dope zirconium oxide and dopant elements. More preferably, anhydrous ethanol is used as the solvent because it has a good dispersing effect, making it less likely for the milled particles to agglomerate.

[0069] In some preferred embodiments, the solid-liquid ratio of the metal oxide powder to the solvent is 1:5 to 10, so that zirconium oxide or oxides of doped elements dissolve in the solvent to form a slurry.

[0070] Step S2 of this application involves stirring and dispersing under pressure to ensure good mixing and dispersion of the slurry, forming a pre-dispersed slurry that can be easily prepared into powder with uniform particle size distribution through subsequent sand milling.

[0071] In some preferred embodiments, the pressure during pressurized stirring dispersion is 0.2–10 MPa, and the stirring time is 10–60 minutes. Pressurized stirring dispersion under these conditions further improves the mixing and dispersion effect of the slurry, which is more conducive to the subsequent preparation of powders with uniform particle size distribution.

[0072] Step S3 of this application involves sand milling the pre-dispersed slurry formed after pressurized stirring and dispersion. This process is not only to obtain powder with small particle size, but more importantly, to ensure elemental doping after flame combustion, and further to ensure that the powder with uniform elemental doping is obtained. A grinding mill can be used for this sand milling process.

[0073] In some preferred embodiments, during the sand milling process, the mill speed is 1300 r / min to 2500 r / min; the milling time is 20 minutes to 160 minutes. Sand milling under these conditions improves milling efficiency and further ensures the acquisition of powder with small particle size and uniform elemental doping.

[0074] In step S4 of this application, the slurry after sand milling is subjected to flame combustion equipment to achieve element doping and simultaneously complete drying, thereby obtaining a doped nano-zirconia product.

[0075] Taking doped nano-zirconia products as an example, the process further includes: injecting filtered combustion-supporting gas into the flame combustion device from the bottom; conveying milled slurry from one side of the flame combustion device; and allowing the airflow to carry the liquid slurry at high speed into the flame combustion area. The rapidly ejected high-temperature flame enables the doping of zirconia and doping elements, while simultaneously causing the solvent to evaporate quickly, achieving instantaneous drying and preventing particle agglomeration. The dried product can be further processed by first performing gas-solid separation under negative pressure, followed by secondary collection of small particles to obtain the doped zirconia nanoparticle product.

[0076] Furthermore, it also includes: stirring, shearing, and crushing the particles falling to the lower port of the flame combustion device. By stirring, dispersing, shearing, and crushing the larger particles falling to the lower port, the purpose of particle agglomeration is further achieved.

[0077] In some preferred embodiments, the temperature of the high-temperature flame in the flame combustion device is controlled at 1000–1600°C. This high-temperature flame allows for the doping of zirconium oxide and doping elements, while simultaneously causing rapid solvent evaporation and instantaneous drying, preventing particle agglomeration and enabling the preparation of element-doped zirconium oxide nanoparticles. Furthermore, since anhydrous ethanol or methanol is used as the solvent, it can be used as fuel after entering the flame combustion device, eliminating the need for an additional heat source after combustion.

[0078] Furthermore, to improve product purity, the combustion-supporting gas used in the flame combustion equipment is one or more of filtered oxygen, air, or oxygen-enriched air. When oxygen-enriched air is used, the oxygen volume concentration is 25%–42%.

[0079] The present application will now be described in more detail with reference to specific embodiments and comparative examples:

[0080] Example 1

[0081] 1) Scandium oxide and zirconium oxide powders with a particle size D90 of less than 50 μm are mixed at a doping ratio of 1:9, and then dissolved in anhydrous ethanol at a solid-liquid ratio of 1:7 to form a mixed slurry;

[0082] 2) The mixed mud is dispersed into a pre-dispersed slurry by pressurized stirring for 30 minutes, wherein the pressure is 5 MPa;

[0083] 3) The pre-dispersed slurry was subjected to sand milling at a speed of 1800 r / min for 60 minutes;

[0084] 4) The mixed slurry is fed into the flame combustion device, and the combustion-supporting gas is filtered oxygen-enriched air with an oxygen volume concentration of 35% and a flame temperature of 1400℃, so as to realize the preparation of scandium oxide-doped zirconia nanoparticles.

[0085] XRD diagram as follows Figure 1 As shown, XRD analysis reveals that the prepared product is cubic zirconia, indicating that Sc 3+ The scandium oxide has completely entered the zirconium oxide, forming a solid solution. The prepared scandium oxide-doped zirconium oxide powder has a particle size of D50 = 0.196 μm, D90 = 0.493 μm, a product purity of 99.99%, and a specific surface area of ​​15.0 m². 2 / g.

[0086] Example 2

[0087] 1) Mix yttrium oxide and zirconium oxide powders with a particle size D90 of less than 50 μm at a doping ratio of 8:92, and then dissolve them in methanol at a solid-liquid ratio of 1:10 to form a mixed slurry;

[0088] 2) The mixed mud is dispersed into a pre-dispersed slurry by ultrasonic pressure mixing for 60 minutes, wherein the pressure is 5 MPa;

[0089] 3) The pre-dispersed slurry was subjected to sand milling at a speed of 2500 r / min for 160 minutes;

[0090] 4) The mixed slurry is fed into a flame combustion device, and the injected combustion gas is filtered air. The flame temperature is 1600℃ to prepare yttrium-doped zirconium oxide nanoparticles with a particle size of D50 = 0.256 μm, D90 = 0.636 μm, a product purity of 99.96%, and a specific surface area of ​​10.2 m². 2 / g.

[0091] Example 3

[0092] 1) Scandium oxide, ytterbium oxide and zirconium oxide powders with a particle size D90 less than 50 μm are mixed at a doping ratio of 9:2:89, and then dissolved in anhydrous ethanol at a solid-liquid ratio of 1:5 to form a mixed slurry;

[0093] 2) The mixed mud is dispersed by ultrasonic pressure stirring for 10 minutes to form a pre-dispersed slurry, wherein the pressure is 10 MPa;

[0094] 3) The pre-dispersed slurry was subjected to sand milling at a speed of 2000 r / min for 100 minutes;

[0095] 4) The mixed slurry is fed into a flame combustion device, and the injected combustion gas is filtered oxygen. The flame temperature is 1000℃ to prepare scandium-ytterbium oxide-doped zirconium oxide nanoparticles with a particle size D50 = 0.236 μm, D90 = 0.584 μm, a product purity of 99.98%, and a specific surface area of ​​12.5 m². 2 / g.

[0096] Example 4

[0097] 1) Mix scandium oxide, aluminum oxide, cerium oxide and zirconium oxide powders with a particle size D90 less than 50 μm at a doping ratio of 10:1:1:88, and then dissolve them in anhydrous ethanol at a solid-liquid ratio of 1:8 to form a mixed slurry;

[0098] 2) The mixed mud is dispersed into a pre-dispersed slurry by ultrasonic pressure mixing for 40 minutes, wherein the pressure is 5 MPa;

[0099] 3) The pre-dispersed slurry was subjected to sand milling at a speed of 1300 r / min for 20 minutes;

[0100] 4) The mixed slurry is fed into a flame combustion device. The injected combustion gas is filtered oxygen-enriched air with an oxygen volume concentration of 42%. The flame temperature is 1200℃. This process achieves the preparation of scandium aluminum oxide cerium doped zirconium oxide nanoparticles with a particle size D50 = 0.291 μm, D90 = 0.658 μm, a product purity of 99.95%, and a specific surface area of ​​8.0 m². 2 / g.

[0101] Comparative Example 1

[0102] The difference from Example 1 is that no pressure was applied during the mixing of the slurry in step 2; the prepared powder product has uneven particle size (D50 = 0.267 μm, D90 = 3.954 μm), and the scandium doping is uneven. The product purity is 99.97%, and the specific surface area is 7.8 m². 2 / g.

[0103] Comparative Example 2

[0104] The difference from Example 1 is that step 3 (sand milling) is omitted; the prepared powder has a particle size of D50 = 3.344 μm and D90 = 6.982 μm, and complete doping cannot be achieved, such as... Figure 2 As shown, a scandium oxide peak can be detected, the product purity is 99.92%, and the specific surface area is 5.3 m². 2 / g.

[0105] Comparative Example 3

[0106] The difference from Example 1 is that step 4 involves centrifugation and ordinary drying, resulting in a powder with a particle size of D50 = 0.834 μm, D90 = 3.482 μm, a product purity of 99.95%, and a specific surface area of ​​7.2 m². 2 / g.

[0107] Comparative Example 4

[0108] The difference from Example 1 is that the solvent was changed from anhydrous ethanol to deionized water, which not only required the addition of a heat source, but also resulted in powder with a particle size of D50 = 0.563 μm, D90 = 2.598 μm, a product purity of 99.91%, and a specific surface area of ​​7.5 m². 2 / g.

[0109] Comparative Example 5

[0110] The difference from Example 1 is that no dispersion and crushing device is installed at the lower port of the flame burner; the product particle size is D50 = 0.3576 μm, D90 = 1.893 μm, the product purity is 99.96%, and the specific surface area is 7.8 m². 2 / g.

[0111] Comparative Example 6

[0112] The difference from Example 1 is that there is no filter at the combustion improver inlet, and the product purity is 99%.

[0113] By comparing with comparative examples, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0114] Comparative Examples 1 to 4 and Comparative Examples 1 to 6 show that the preparation method provided in this application can produce particles with a D50 of less than 0.3 μm, a D90 of less than 0.7 μm, a product purity of greater than 99.9%, and a specific surface area of ​​8–15 m². 2 / g of oxide-doped zirconium oxide powder.

[0115] Comparing Examples 1 to 4 with Comparative Example 1, it can be seen that the preparation method provided in this application is beneficial for obtaining powders with uniform particle size and uniform element doping.

[0116] Comparing Examples 1 to 4 with Comparative Example 2, it can be seen that the preparation method provided in this application is beneficial for obtaining powders with small particle size and uniform element doping.

[0117] Comparing Examples 1 to 4 with Comparative Example 3, it can be seen that the preparation method provided in this application is beneficial for obtaining powders with small particle size.

[0118] Comparing Examples 1 to 4 with Comparative Example 4, it can be seen that the preparation method provided in this application is beneficial for obtaining powders with small particle size.

[0119] Comparing Examples 1 to 4 with Comparative Example 5, it can be seen that the preparation method provided in this application is beneficial for obtaining powders with small particle size.

[0120] Comparing Examples 1 to 4 with Comparative Example 6, it can be seen that the preparation method provided in this application is beneficial for obtaining high-purity powder.

[0121] The description of this invention is given for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing nano-zirconia powder, characterized in that, include: S1: Dissolve metal oxide powder with a particle size D90 less than 50 μm in a solvent in a certain proportion to form a slurry; wherein, the solvent is one of anhydrous ethanol and methanol; the metal oxide powder is zirconium oxide and oxides of doped elements. S2: The mud is pressurized, stirred, and dispersed to form a pre-dispersed slurry; S3: The pre-dispersed slurry is subjected to sand milling treatment; S4: The slurry after sand milling is transported to a flame combustion device to achieve doping and complete drying to obtain doped nano-zirconia products.

2. The method for preparing nano-zirconia powder according to claim 1, characterized in that, In the metal oxide powder, the molar ratio of the oxide of the dopant element to zirconium oxide is (8-12):(92-88); the oxide of the dopant element is one or more of scandium oxide, cerium oxide, ytterbium oxide, aluminum oxide, and yttrium oxide.

3. The method for preparing nano-zirconia powder according to claim 1, characterized in that, The solid-liquid ratio of the metal oxide powder to the solvent is 1:5 to 10.

4. The method for preparing nano-zirconia powder according to claim 1, characterized in that, When dispersing under pressure, the pressure is 0.2MPa to 10MPa and the stirring time is 10 minutes to 60 minutes.

5. The method for preparing nano-zirconia powder according to claim 1, characterized in that, The grinding process was carried out using a grinding machine with a speed of 1300 r / min to 2500 r / min and a grinding time of 20 minutes to 160 minutes.

6. The method for preparing nano-zirconia powder according to claim 1, characterized in that, The flame temperature in the flame combustion device is 1000℃~1600℃.

7. The method for preparing nano-zirconia powder according to claim 1, characterized in that, The doped nano-zirconia product is cubic in phase, with a particle size D50 less than 0.3 μm, D90 less than 0.7 μm, a purity greater than 99.9%, and a specific surface area of ​​8 m². 2 / g~15m 2 / g.

8. The method for preparing nano-zirconia powder according to claim 1, characterized in that, Step S4 specifically includes: The slurry after sand milling is transported from one side of the flame combustion device to the flame combustion device. The filtered combustion-supporting gas is sprayed into the flame combustion device from the bottom. The airflow carries the liquid slurry into the flame combustion area at high speed. The high-temperature flame is used to dope zirconium oxide with the oxide of the doping element and complete the drying process to obtain the doped nano zirconium oxide product. Shear and crush the particles falling to the lower port of the flame combustion device; Gas-solid separation is performed on the dried product discharged from the top of the flame combustion device; After gas-solid separation and collection, small particles are collected in a secondary stage.

9. An apparatus for preparing nano-zirconia powder, characterized in that, include: Flame combustion equipment is used to receive slurry after sand milling to achieve doping and complete drying, thereby obtaining doped nano-zirconia products; The flame combustion device has a combustion aid inlet at the bottom, a slurry inlet on the side wall, and a stirring and crushing device inside. The stirring and crushing device is located at the lower port and is lower than the slurry inlet. The flame combustion device has an outlet at the top. A filter is also provided at the combustion aid inlet.

10. The apparatus for preparing nano-zirconia powder according to claim 9, characterized in that, Also includes: The feeding device is connected to the slurry inlet of the flame combustion equipment and is used to meter and continuously transport the slurry after sand milling to the flame combustion equipment. The outlet of the flame combustion device is connected to a cyclone separator, and the outlet of the cyclone separator is connected to a collection device. The collection device is used for secondary collection of small particles after cyclone separation, and the collection device is also connected to a negative pressure device.

11. The apparatus for preparing nano-zirconia powder according to claim 10, characterized in that, The feeding device is a liquid pump; The collection device uses a high-temperature resistant sintered plate.

12. The apparatus for preparing nano-zirconia powder according to claim 9, characterized in that, Also includes: A mud preparation apparatus is used to dissolve metal oxide powder with a particle size D90 of less than 50 μm in a solvent in a certain proportion to form mud; wherein, the solvent is one of anhydrous ethanol and methanol; and the metal oxide powder is zirconium oxide and oxides of doped elements. A pressure mixing and dispersing device is used to pressurize and disperse mud to form a pre-dispersed slurry; A sand milling device is used to sand mill pre-dispersed slurry.

13. A nano-zirconia powder, characterized in that, The doped nano-zirconia product is prepared by the method for preparing nano-zirconia powder according to any one of claims 1-8.

14. An application of nano-zirconia powder in a solid oxide fuel cell, characterized in that, The nano-zirconia powder is used as a raw material for the electrolyte film, and the nano-zirconia powder is prepared by the preparation method of nano-zirconia powder according to any one of claims 1-8.

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