Device and method for preparing nickel-stabilized aluminum oxide nano powder

Abstract

The invention discloses a device and method for preparing nickel-stabilized aluminum oxide nano powder, the device comprises a flame synthesis tank, an aluminum oxide synthesizer and a nickel oxide synthesizer are arranged on the side wall of the flame synthesis tank in an up-and-down adjacent mode, and the two synthesizers are both provided with three independent air, fuel and raw material injection mechanisms; outlets of the injection mechanisms incline towards the bottom of the flame synthesis tank; the top of the flame synthesis tank is communicated with a negative pressure mechanism for sucking out synthetic products of the two synthesizers from the top; the method comprises the following steps: S1, respectively preparing an aluminum precursor solution and a nickel precursor solution, adding a dispersing agent into the two precursor solutions, and adjusting the pH value of the two precursor solutions; s2, the solution obtained in the step S1 is sprayed into a flame synthesis tank through spraying mechanisms of two synthesizers, and flames at the two synthesizers are ignited at the same time; and S3, starting a negative pressure mechanism to suck out a synthetic product in the flame synthesis tank, namely the nickel-stabilized aluminum oxide nano-powder. The method can be used for simultaneously preparing nickel and aluminum material nanoscale powder and uniformly mixing the nickel and aluminum material nanoscale powder.

Description

Technical Field

[0001] The present invention relates to the preparation of nickel-stabilized alumina nanopowders, and particularly to a device and method for preparing nickel-stabilized alumina nanopowders. Background Art

[0002] Nickel-stabilized alumina nanopowder materials have excellent thermal stability, high ionic conductivity and mechanical strength, especially outstanding at high temperatures, and are widely used in fields such as electrolytes of solid oxide fuel cells, oxygen sensors, thermal barrier coatings and biomedical materials. Technologies for preparing nickel-stabilized alumina nanopowders mainly include co-precipitation method, sol-gel method, hydrothermal method, spray pyrolysis method and flame synthesis method, etc. Among them, the flame synthesis method has advantages such as fast reaction speed, small and uniform particle size, high purity, simple process and wide applicability, and can complete synthesis in one step and achieve continuous production, especially suitable for large-scale preparation of high-performance nickel-stabilized alumina nanopowders.

[0003] In existing devices, the flame synthesis method is used to prepare nickel-stabilized alumina nanopowder materials by separately preparing the corresponding nickel and aluminum material powders and then mixing them, which easily affects the quality of the finished product. Separately preparing and then blending them easily leads to uneven doping, affecting the stability and conductivity of the material.

[0004] Therefore, the traditional technology still needs to be improved. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a device and method for preparing nickel-stabilized alumina nanopowders that can simultaneously prepare nickel and aluminum material powders and make the two blend evenly.

[0006] Technical Solution: To achieve the above object, the device for preparing nickel-stabilized alumina nanopowders of the present invention includes a flame synthesis tank. An alumina synthesizer and a nickel oxide synthesizer are provided adjacent to each other up and down on the side wall of the flame synthesis tank. Both synthesizers are provided with three independent injection mechanisms for air, fuel and raw materials, and the outlets of the injection mechanisms are all inclined towards the bottom of the flame synthesis tank; a negative pressure mechanism for sucking out the synthesis products of the two synthesizers from the top is connected to the top of the flame synthesis tank.

[0007] Based on the above technical solution, the alumina synthesizer and the nickel oxide synthesizer are arranged adjacent to each other up and down on the side wall of the flame synthesis tank, so that alumina and nickel oxide can be synthesized in the same device. Moreover, the two synthesizers are arranged adjacent to each other up and down. In this way, the powders synthesized by the two synthesizers can be in contact with each other and evenly mixed during the process of being attracted and moving upward by the negative pressure mechanism arranged at the top of the flame synthesis tank, so that the finally obtained nickel-stabilized alumina nanopowders can be evenly blended, improving the stability and conductivity of the finally obtained nickel-stabilized alumina nanopowders.

[0008] Preferably, the nickel oxide synthesizer is located below the alumina synthesizer.

[0009] The alumina synthesizer is arranged above because the molecular weight of alumina is larger than that of nickel oxide. In this way, the relatively lighter nickel oxide moves faster during the upward movement, while alumina moves slower, enabling nickel oxide to better mix into alumina. If the nickel oxide synthesizer is arranged above, most of the nickel oxide is easily sucked away by the negative pressure mechanism first, leaving only a small part to be mixed with alumina, resulting in low uniformity of the final blending.

[0010] Preferably, a stepped inclined boss for installing two synthesizers is provided on the side wall of the flame synthesis tank.

[0011] By providing a stepped inclined boss on the side wall of the flame synthesis tank, the precursor solutions of alumina and nickel oxide can first undergo combustion synthesis to form corresponding powders in the cavity inside the boss after being sprayed into the flame synthesis tank and then enter the flame synthesis tank to be sucked out by the negative pressure mechanism, avoiding some precursor solutions being directly sucked out by the negative pressure mechanism without sufficient reaction in time. Moreover, setting the stepped boss can also isolate the combustion synthesis processes of the alumina and nickel oxide precursor solutions from each other, avoiding mutual interference between the two.

[0012] Preferably, a temperature-regulating burner for adjusting the temperature inside the flame synthesis tank is provided on the side wall of the flame synthesis tank.

[0013] Setting the temperature-regulating burner can better adjust the temperature inside the flame synthesis tank, thereby ensuring the effective synthesis of alumina and nickel oxide.

[0014] Preferably, the bottom of the flame synthesis tank is semi-cylindrical.

[0015] When the bottom of the flame synthesis tank is semi-cylindrical, the alumina and nickel oxide powders ejected and synthesized by the alumina synthesizer and the nickel oxide synthesizer can be better guided to flow upward in the flame synthesis tank for mixing after impacting the bottom.

[0016] Preferably, a diversion device for guiding external air to the bottom of the flame synthesis tank to form an air film at the bottom is provided below the two synthesizers of the flame synthesis tank.

[0017] Setting the diversion device can introduce external air to form an air film at the bottom of the flame synthesis tank, which can prevent the adhesion and consolidation of high-temperature alumina and nickel oxide nano powder materials on the inner wall surface of the flame synthesis tank.

[0018] The method for preparing the nickel-stabilized alumina nano powder of the present invention includes the following steps: S1. Respectively prepare precursor solutions of aluminum and nickel, add a dispersant to both precursor solutions, and adjust the pH values of the two precursor solutions to [1, 3] to obtain pretreated precursor solutions; S2. Spray the pretreated precursor solutions of aluminum and nickel obtained in step S1 into the flame synthesis tank through the injection mechanisms of the alumina synthesizer and the nickel oxide synthesizer respectively. At the same time, the injection mechanisms of the two synthesizers inject air and fuel and ignite them. S3. Start the negative pressure mechanism to suck out the synthesis product in the flame synthesis tank, which is the nickel-stabilized alumina nanopowder.

[0019] In the method of the present invention, a dispersant is added to the precursor solution and adsorbed on the surface of solid particles, reducing the interfacial tension between liquid-liquid or solid-liquid, making the surface of the aggregated solid particles hydrophilic and uniformly dispersed. In addition, the dispersant forms an adsorption layer on the surface of the solid particles, increasing the charge on the surface of the solid particles and enhancing the reaction force between particles, which can prevent particle sedimentation and aggregation, forming a stable suspension, thereby improving the stability of the precursor solution and the dispersibility of the finally prepared nickel-stabilized alumina nanopowder. Adjusting the pH value of the precursor solution to [1, 3] can affect the hydrolysis rate. The hydrolysis process is generally carried out under the condition that the pH value ranges from 3.5 to 10.0, but the optimal pH value is 5.5 to 6.5. When the pH value is regulated to [1, 3], the hydrolysis reaction basically stops, and the solution containing the nickel source and the aluminum source can maintain a stable composition, thus synthesizing powders with smaller particle size and higher purity. That is, adding a dispersant and adjusting the pH value when preparing the pretreated precursor solution improve the quality and dispersibility of the flame-synthesized alumina and nickel oxide powders, making the two finally mix more uniformly. Moreover, preparing and mixing the pretreated precursor solution with the device of the present invention can further improve the mixing uniformity of the alumina and nickel oxide powders, and improve the stability and conductivity of the finally obtained nickel-stabilized alumina nanopowder.

[0020] Preferably, the dispersant in step S1 includes, but is not limited to, surfactants such as carboxylates and amine salts, organic acids such as propionic acid and oleic acid amide, or high molecular polymers such as polyvinyl alcohol and methyl cellulose, which can achieve a better dispersion effect and make the prepared powder more uniformly dispersed.

[0021] Beneficial effects: In the device of the present invention, the alumina synthesizer and the nickel oxide synthesizer are arranged adjacent to each other up and down on the side wall of the flame synthesis tank, so that the alumina and nickel oxide powders can be synthesized in the same device and can be mixed uniformly during the upward movement under the suction of the negative pressure mechanism, making the finally prepared nickel-stabilized alumina nanopowder uniformly blended. In the method of the present invention, by adding a dispersant and adjusting the pH value in the precursor solutions of alumina and nickel oxide, the generated alumina and nickel oxide powders have uniform texture and high dispersion degree, so that the two can be better mixed uniformly. Description of the Drawings

[0022] Figure 1It is a schematic diagram of the overall structure of the device for preparing nickel-stabilized alumina nanopowders of the present invention; Figure 2 It is the front view of the flame synthesis tank; Figure 3 It is the side view of the flame synthesis tank; Figure 4 It is a schematic diagram of the flame distribution and gas flow inside the flame synthesis tank; Figure 5 It is the SEM of nickel-stabilized alumina nanopowders Figure 1 ; Figure 6 It is the SEM of nickel-stabilized alumina nanopowders Figure 2 。 Specific embodiments

[0023] To make the above objects, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application will be described in detail below. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0024] As Figure 1 shown, the device for preparing nickel-stabilized alumina nanopowders of the present invention includes a flame synthesis tank 1. On the side wall of the flame synthesis tank 1, an alumina synthesizer 2 and a nickel oxide synthesizer 3 are arranged adjacent to each other up and down. Both synthesizers are provided with three independent injection mechanisms for air, fuel and raw materials, and the outlets of the injection mechanisms are all inclined towards the bottom of the flame synthesis tank 1. A negative pressure mechanism 4 is connected to the top of the flame synthesis tank 1 to suck out the synthesis products of the two synthesizers from the top.

[0025] The flame synthesis tank 1 is a closed cavity for accommodating the atomized synthesis flame; the upper end of the flame synthesis tank 1 is the outlet of the nickel-stabilized alumina nanopowder gas flow, which is connected and communicated with the gas flow discharge pipe 9; a powder collector 10 and a negative pressure mechanism 4 are also sequentially connected in the gas flow discharge pipe 9; the powder collector 10 is used to collect the nickel-stabilized alumina nanopowders in the gas flow; the bottom of the flame synthesis tank 1 is semi-cylindrical, forming a semi-circular cavity 11, and the upper part of the corresponding flame synthesis tank 1 is rectangular; the semi-circular cavity 11 is convenient for the flow and guiding of the gas flow inside; the negative pressure mechanism 4 plays a suction role, and while sucking the gas flow containing nickel-stabilized alumina nanopowders, it plays a role in constructing the negative pressure inside the flame synthesis tank 1.

[0026] On the upper part of the left side wall of the flame synthesis tank 1, a high-temperature observation window 12 is installed; the high-temperature observation window 12 is rectangular, and the material is high-temperature resistant transparent quartz glass with a certain thickness; outside the high-temperature observation window 12, an infrared detection camera 13 is provided; the infrared detection camera 13 is used to observe the flame morphology characteristics and flame stability inside the flame synthesis tank 1 through the high-temperature observation window 12; the infrared detection camera 13 is connected to the flame controller 15 through a data transmission line 14; in the middle of the left side wall of the flame synthesis tank 1, a thermocouple 16 is installed; the thermocouple 16 is used to monitor the temperature inside the flame synthesis tank 1; the thermocouple 16 is connected to the flame controller 15 through a data transmission line 14.

[0027] The infrared detection camera 13 and the thermocouple 16 can transmit the flame and temperature data in the flame synthesis tank 1 to the flame controller 15; the flame controller 15 can analyze the flame observation and temperature measurement data, and feedback to each flow regulating valve to automatically adjust the temperature distribution and flame stability.

[0028] In the middle of the left side wall of the flame synthesis tank 1, near the position of the thermocouple 16, a temperature-regulating burner 6 is installed; the temperature-regulating burner 6 is used to form a high-temperature flame, so as to adjust the mixing and sintering temperature environment of alumina powder and nickel oxide powder; a fuel channel is provided at the center of the temperature-regulating burner 6, and an annular gas channel is provided outside the fuel channel. The gas channel and the fuel channel are respectively connected to the air compression storage tank 19 and the combustible gas cylinder 20. The combustible gas cylinder 20 is used to store combustible gases such as methane or propane.

[0029] On the right side wall of the flame synthesis tank 1, a stepped inclined boss 5 is provided. The stepped inclined boss 5 includes an upper inclined arch 5-1 and a lower inclined arch 5-2 with the same shape and size, both of which are inclined single-step structures; on the upper inclined wall surface of the upper inclined arch 5-1, an alumina synthesizer 2 is vertically installed; on the upper inclined wall surface of the lower inclined arch 5-2, a nickel oxide synthesizer 3 is vertically installed.

[0030] At the center of the alumina synthesizer 2, an alumina atomizing nozzle 2-1 is coaxially arranged. Outside the alumina atomizing nozzle 2-1, two annular gas channels and fuel channels are respectively provided. The alumina atomizing nozzle 2-1 is connected to the alumina precursor tank 17 storing the alumina precursor solution; at the center of the nickel oxide synthesizer 3, a nickel oxide atomizing nozzle 3-1 is coaxially arranged. Outside the nickel oxide atomizing nozzle 3-1, two annular gas channels and fuel channels are respectively provided. The nickel oxide atomizing nozzle 3-1 is connected to the nickel oxide precursor tank 18 storing the nickel oxide precursor solution. The gas channels and fuel channels of the two synthesizers are respectively connected to the air compression storage tank 19 and the combustible gas cylinder 20; the atomizing nozzles, gas channels and fuel channels of the two synthesizers are respectively the injection mechanisms for their raw materials, air and fuel.

[0031] A flow guiding device 7 is provided below the flame synthesis tank 1 between two synthesizers. The flow guiding device 7 includes an air flow inlet pipe 21 and a flow guiding plate 22 arranged on the side wall of the flame synthesis tank 1. The flow guiding plate 22 is an L-shaped plate matching the bottom of the flame synthesis tank 1. The air flow inlet pipe 21 is connected to the air compression storage tank 19. The air flow inlet pipe 21 introduces air into the flame synthesis tank 1 and impacts on the flow guiding plate 22. Under the action of the flow guiding plate 22, the air flow will turn to the semi-circular cavity 11 and further be guided towards the upper part of the flame synthesis tank 1. During this process, an air film will be formed at the bottom of the flame synthesis tank 1, which can prevent the adhesion and consolidation of high-temperature alumina and nickel oxide nanopowder materials on the inner wall surface of the flame synthesis tank.

[0032] Corresponding booster pumps and valves can be provided on the pipelines connected to the air compression storage tank 19 and the combustible gas cylinder 20 to control whether the gas or liquid flows, as well as the flow rate and pressure, etc.

[0033] An igniter 8 is installed at the lower part of the right side wall surface of the flame synthesis tank 1, near the lower edge of the lower inclined arch 5-2. The igniter 8 is used to ignite the flame inside the flame synthesis tank 1.

[0034] The preparation method of the nickel-stabilized alumina powder material described in the present invention includes the following specific steps: S1. Prepare the precursor solutions of aluminum and nickel respectively: Mix an aluminum salt (including but not limited to aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum citrate, etc.) and a solvent (including but not limited to organic solvents such as ethanol, propanol, acetic acid, etc. or inorganic solvents such as water, etc.) in a mass ratio in the range of 1:2 to 1:4, then add a dispersant (but not limited to surfactants such as carboxylates, amine salts, etc., or organic acids such as propionic acid, oleic acid amide, etc., or polymer polymers such as polyvinyl alcohol, methyl cellulose, etc.) in an amount 0.5 to 1.5 times the mass of the aluminum salt, and finally add an acid solution to make the pH of the solution [1, 3] to obtain the precursor solution of aluminum; similarly, mix a nickel salt (including but not limited to nickel chloride, nickel nitrate, nickel sulfate, nickel acetate, etc.) and a solvent (including but not limited to organic solvents such as ethanol, propanol, acetic acid, etc. or inorganic solvents such as water, etc.) in a mass ratio in the range of 1:4 to 1:10, then add a dispersant (but not limited to surfactants such as carboxylates, amine salts, etc., or organic acids such as propionic acid, oleic acid amide, etc., or polymer polymers such as polyvinyl alcohol, methyl cellulose, etc.) in an amount 2 to 4 times the mass of the nickel salt, and finally add an acid solution to make the pH of the solution [1, 3] to obtain the precursor solution of nickel.

[0035] S2. Spray the aluminum precursor solution and the nickel precursor solution obtained in step S1 into the flame synthesis tank 1 through the spraying mechanisms of the alumina synthesizer 2 and the nickel oxide synthesizer 3 respectively. The pumping flow rates of the aluminum precursor solution and the nickel precursor solution are maintained in the range of [0.5 L / h, 3 L / h]; meanwhile, the spraying mechanisms of the two synthesizers spray oxidants (including but not limited to air, oxygen, etc.) and fuels (including but not limited to methane, ethane, propane, natural gas, etc.) and ignite them, where the flow rate ratio of the oxidant to the fuel is maintained in the range of [10 - 20]; specifically, it includes the following processes: Simultaneously open the pipelines connecting the gas channels and the fuel gas channels on the alumina synthesizer 2 and the nickel oxide synthesizer 3, start the igniter 8, ignite the combustible gas, and construct a pilot flame at the outlet of the alumina synthesizer 2 and a pilot flame at the outlet of the nickel oxide synthesizer 3.

[0036] Open the pipeline connecting the alumina atomizing nozzle 2 - 1 and the nickel oxide atomizing nozzle 3 - 1, so as to form an alumina precursor atomizing jet and a nickel oxide precursor atomizing jet at the outlets of the alumina atomizing nozzle 2 - 1 and the nickel oxide atomizing nozzle 3 - 1.

[0037] Through the above steps, an atomizing synthesis flame for synthesizing alumina powder is constructed at the outlet of the alumina synthesizer 2, and the flame temperature here is controlled between 2500°C and 3000°C; an atomizing synthesis flame for synthesizing nickel oxide powder is constructed at the outlet of the nickel oxide synthesizer 3, and the flame temperature here is controlled between 1500°C and 2000°C.

[0038] Simultaneously open the valve located on the gas flow inlet pipe 21. Under the downward guiding action of the deflector 22, it flows vertically downward, and an air film is constructed on the inner wall of the semi - circular cavity 11 and the left vertical inner wall area of the flame synthesis tank 1.

[0039] S3. Turn on the negative pressure mechanism 4 to suck out the synthesis product in the flame synthesis tank 1, which is the nickel - stabilized alumina nanometer powder. Specifically, it includes the following processes: Under the suction effect of the negative pressure mechanism 4 on the interior of the flame synthesis tank 1 (the negative pressure mechanism controls the pressure inside the flame synthesis tank between - 0.5 kPa and - 30 kPa (relative to the atmospheric pressure)), the alumina atomizing synthesis flame at the outlet of the alumina synthesizer 2 and the nickel oxide atomizing synthesis flame at the outlet of the nickel oxide synthesizer 3 will turn upward and mix with each other, and then flow out from the upper outlet; during the mixing process of the high - temperature gas flow containing alumina and nickel oxide nanometer powder, the doping uniformity of nickel and aluminum elements will be improved.

[0040] Meanwhile, by adjusting the flame temperature at the outlet of the temperature-adjusting burner 6, corresponding electric flow regulating valves can be respectively arranged in the gas passage and the fuel passage of the temperature-adjusting burner 6 and connected to the controller 15. The controller 15 dynamically adjusts the flow ratio of air and gas according to the temperature in the flame synthesis tank 1 detected by the thermocouple 16 to adjust the temperature in the flame synthesis tank 1 and ensure that the temperature reaches the target value. The temperature of the blending and sintering links of the adjustable alumina and nickel oxide nano powders can be further adjusted to optimize and improve the performance of the nickel-stabilized alumina nano powders.

[0041] The finally synthesized nickel-stabilized alumina nano powder material will be collected by the powder collector 10.

[0042] The present application will be described below in conjunction with specific embodiments, but the present application is not limited to the following embodiments. It should be understood that the appended claims define the scope of the present application. Under the guidance of the concept of the present application, those skilled in the art should realize that certain changes made to the embodiments of the present application will be covered by the spirit and scope of the claims of the present application.

[0043] The following are specific embodiments.

[0044] Step 1: Preparation of the precursor solution for the atomization synthesis of alumina nano powders, and the specific steps are as follows: 1) Select aluminum chloride as the aluminum source, and mix propanol and water in a ratio of 3:1 as the solvent; 2) Dissolve the aluminum source in the solvent, and keep the mass ratio with the solvent at 1:3.5 to ensure complete dissolution and make a mixed solution; 3) Add 4% of polyvinylpyrrolidone in the mass of the mixed solution as a dispersant to improve the solution stability and powder dispersibility; 4) Adjust the pH value by mixing a small amount of propionic acid solution in the solution to make the solution acidic, and the pH value is 3; Step 2: Preparation of the precursor solution for the atomization synthesis of nickel oxide nano powders, and the specific steps are as follows: 1) Select nickel chloride as the nickel source, and mix propanol and water in a ratio of 3:1 as the solvent; 2) Dissolve the nickel source in the solvent, and keep the mass ratio with the solvent at 1:3.5 to ensure complete dissolution and make a mixed solution; 3) Add 4% of polyvinylpyrrolidone in the mass of the mixed solution as a dispersant to improve the solution stability and powder dispersibility; 4) Adjust the pH value by mixing a small amount of propionic acid solution in the solution to make the solution acidic, and the pH value is 3; Step 3: Atomization synthesis of nickel-stabilized alumina powder, and the specific steps are as follows: 1) Open the alumina air pipe and the alumina combustible gas pipe connected to the alumina synthesizer, and at the same time open the nickel oxide combustible gas pipe and the nickel oxide air pipe connected to the nickel oxide synthesizer; 2) Start the igniter to ignite the combustible gas and form a duty flame at the outlet of the alumina synthesizer and a duty flame at the outlet of the nickel oxide synthesizer; 3) Open the alumina precursor pipe and the alumina atomizing nozzle, and at the same time open the nickel oxide precursor pipe and the nickel oxide atomizing nozzle, so as to form an alumina precursor atomizing jet and a nickel oxide precursor atomizing jet at the outlets of the alumina atomizing nozzle and the nickel oxide atomizing nozzle; 4) Through the above steps, an atomizing synthesis flame for synthesizing alumina powder is constructed at the outlet of the alumina synthesizer, and an atomizing synthesis flame for synthesizing nickel oxide powder is constructed at the outlet of the nickel oxide synthesizer; 5) Open the valve on the wall-attached air branch pipe, so that a part of the air flows through the wall-attached air inlet pipe, and under the downward guiding action of the deflector, it flows vertically downward, and a layer of air film is constructed at the near-wall surface of the semi-circular cavity and the lower near-wall area of the left vertical wall surface of the flame synthesis cavity; 6) Under the suction action of the induced draft fan on the inside of the flame synthesis cavity, the alumina atomizing synthesis flame at the outlet of the alumina synthesizer and the nickel oxide atomizing synthesis flame at the outlet of the nickel oxide synthesizer will turn upward and mix with each other, and then flow out from the upper outlet; during the mixing process of the high-temperature gas flow containing alumina and nickel oxide nano-powders, the doping uniformity of nickel and aluminum elements will be improved; 7) At the same time, by adjusting the flame temperature at the outlet of the temperature-regulating burner, the temperature of the mixing and sintering links of alumina and nickel oxide nano-powders is adjusted to further optimize and improve the performance of nickel-stabilized alumina nano-powders; 8) Finally, collect the synthesized nickel-stabilized alumina nano-powder material with a powder collector.

[0045] Figure 5 and 6 The SEM images of... show the microstructure of the nickel-stabilized alumina nano-powders prepared by the present invention. This material is at the nano-level with a relatively small particle size of about dozens of nanometers; and it has a loose structure, good dispersibility, and no obvious agglomeration.

[0046] The above embodiments only represent the implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent application should be subject to the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. A preparation device for nickel-stabilized alumina nanopowder, comprising a flame synthesis tank (1), characterized in that: On the side wall of the flame synthesis tank (1), an alumina synthesizer (2) and a nickel oxide synthesizer (3) are arranged adjacent to each other up and down. Both synthesizers are provided with three independent injection mechanisms for air, fuel, and raw materials, and the outlets of the injection mechanisms are all inclined towards the bottom of the flame synthesis tank (1). A negative pressure mechanism (4) for sucking out the synthesis products of the two synthesizers from the top is connected to the top of the flame synthesis tank (1).

2. The synthesis device according to claim 1, characterized in that: The nickel oxide synthesizer (3) is located below the alumina synthesizer (2).

3. The synthesis device according to claim 1, characterized in that: The side wall of the flame synthesis tank (1) is provided with a stepped inclined boss (5) for installing the two synthesizers.

4. The synthesis device according to claim 1, characterized in that: The side wall of the flame synthesis tank (1) is provided with a temperature-regulating burner (6) for regulating the temperature inside the flame synthesis tank (1).

5. The synthesis device according to claim 1, characterized in that: The bottom of the flame synthesis tank (1) is semi-cylindrical.

6. The synthesis device according to claim 5, wherein: Below the two synthesizers of the flame synthesis tank (1), a diversion device (7) for guiding external air to flow towards the bottom of the flame synthesis tank (1) to form an air film at the bottom is provided.

7. A method for preparing nickel-stabilized alumina nanopowder using the synthesis device according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Prepare the precursor solutions of aluminum and nickel respectively. Add a dispersant to both precursor solutions, and adjust the pH values of the two precursor solutions to [1, 3] to obtain pre-treated precursor solutions. S2. Spray the pre-treated precursor solutions of aluminum and nickel obtained in step S1 into the flame synthesis tank (1) through the injection mechanisms of the alumina synthesizer (2) and the nickel oxide synthesizer (3) respectively. At the same time, the injection mechanisms of the two synthesizers inject air and fuel and ignite them. S3. Turn on the negative pressure mechanism (4) to suck out the synthesis products in the flame synthesis tank (1), which is the nickel-stabilized alumina nano-powder.

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