Gamma-Al2O3, preparation method thereof and beta ''-Al2O3 solid electrolyte
Through industrial aluminum hydroxide and grain regulator solvents thermal reactions and roasting transformation methods, prepare high-purity, uniform granular γ-Al2O3, and solve the requirements of β ″-Al2O3 solid electrolyte equipment in the existing technology. The high cost problem has achieved low cost and efficient preparation process.
Patent Information
- Application Number
- CN202411518295.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-01-28
AI Technical Summary
The prior art preparation method for sodium salt batteries β″-Al2O3 solid electrolyte has high equipment requirements, high production costs, and little reports on ceramic powder raw materials.
The solvent thermal reaction was used to use industrial aluminum hydroxide and grain control agents to obtain an intermediate of alumina alumina water compounds, and to obtain γ-Al2O3 through baking translational crystals, as the β-il2O3 solid electrolyte.
The high-purity, particle size, and high activity of γ-Al2O3 are realized, reducing production costs and suitable for industrial application.
Smart Images
Figure CN119370874A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of material preparation for new energy batteries, and in particular to a γ-Al2O3 and a preparation method thereof, and a β″-Al2O3 solid electrolyte. Background Art
[0002] Sodium salt battery is a new type of electrochemical energy storage battery, which has attracted the attention of many researchers due to its high energy density, high safety, long life and high conversion efficiency. β″-Al2O3 solid electrolyte is used in sodium batteries and gas sensors due to its high ionic conductivity, stability and safety performance. It plays a dual role as electrolyte and diaphragm and has unique market prospects in energy storage system technology and new energy electric vehicles. The quality of β″-Al2O3 solid electrolyte directly affects the performance of sodium salt batteries.
[0003] The preparation of β″-Al2O3 solid electrolyte ceramics includes many complex steps such as powder synthesis, molding, and sintering. Among them, the powder synthesis process mainly includes traditional solid phase method (high temperature solid phase method) and liquid phase method (sol-gel method, hydrothermal synthesis method, co-precipitation technology, etc.), but there are not many reports on ceramic powder raw materials. At present, the method used for sodium salt battery solid electrolyte has high equipment requirements and high production cost. Summary of the invention
[0004] The present application provides a γ-Al2O3 and a preparation method thereof, and a β″-Al2O3 solid electrolyte to solve the following technical problems: providing a preparation method for raw materials for a β″-Al2O3 solid electrolyte.
[0005] In a first aspect, the present application provides a method for preparing γ-Al2O3, the method comprising:
[0006] Under the conditions of a first set temperature and stirring, industrial aluminum hydroxide and a grain control agent are subjected to a solvothermal reaction to obtain an aluminum oxide hydrate intermediate;
[0007] Under the condition of a second set temperature, the alumina hydrate intermediate is calcined to adjust the specific surface area of the calcined product to obtain γ-Al2O3.
[0008] Optionally, the first set temperature is 160° C. to 200° C.; and / or,
[0009] The stirring speed is 600 r / min to 1000 r / min.
[0010] Optionally, the grain control agent includes at least one of the following: boehmite, pseudo-boehmite, and activated alumina.
[0011] Optionally, the median particle size of the grain control agent is less than 5 μm.
[0012] Optionally, the weight of the grain control agent is 0.5% to 25% of the weight of the industrial aluminum hydroxide.
[0013] Optionally, in the solvent thermal reaction system, the concentration of the industrial aluminum hydroxide is 200 g / L to 350 g / L.
[0014] Optionally, the second set temperature is 700°C to 900°C.
[0015] Optionally, the γ-Al2O3 meets the following indicators:
[0016] The median particle size is 5μm to 25μm, and the specific surface area is 10m 2 / g~30m 2 / g, purity is>99.9%, and bulk density is 0.3g / cc~0.8g / cc.
[0017] In a second aspect, the present application provides a γ-Al2O3, wherein the γ-Al2O3 is prepared by any method described in the first aspect.
[0018] In a third aspect, the present application provides a β″-Al2O3 solid electrolyte, wherein the raw material of the β″-Al2O3 solid electrolyte includes the γ-Al2O3 described in any one of the second aspects.
[0019] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0020] The preparation method of γ-Al2O3 provided in an embodiment of the present application comprises: under the conditions of a first set temperature and stirring, industrial aluminum hydroxide and a grain control agent are subjected to a solvothermal reaction to obtain an alumina hydrate intermediate; under the conditions of a second set temperature, the alumina hydrate intermediate is calcined to control the specific surface area of the calcined product to obtain γ-Al2O3. Under the conditions of a first set temperature and stirring, industrial aluminum hydroxide and a grain control agent are subjected to a one-step solvothermal reaction, and the grain control agent can control the morphology, particle size and distribution of the alumina hydrate intermediate; under the conditions of a second set temperature, the alumina hydrate intermediate is activated and calcined to crystallize to control the specific surface area of the calcined product to obtain γ-Al2O3 with high purity, uniform particle size, high activity and high specific surface area; the γ-Al2O3 can be used as a raw material for a β″-Al2O3 solid electrolyte. The method is simple, suitable for industrialization, and has low production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0023] Figure 1 A schematic diagram of a process for preparing γ-Al2O3 provided in an embodiment of the present application;
[0024] Figure 2 A SEM image (low magnification) of γ-Al2O3 provided in Example 1 of the present application;
[0025] Figure 3 A SEM image (high magnification) of γ-Al2O3 provided in Example 1 of the present application;
[0026] Figure 4 This is an XRD diagram of γ-Al2O3 provided in Example 1 of the present application. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0028] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0029] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "include", "comprise", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, wherein a, b, c can be single or multiple, respectively.
[0030] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0031] In a first aspect, the present application provides a method for preparing γ-Al2O3. Figure 1 A schematic flow chart of a method for preparing γ-Al2O3 provided in an embodiment of the present application; see Table 1, the method comprises:
[0032] S1. Under the conditions of a first set temperature and stirring, industrial aluminum hydroxide and a grain control agent are subjected to a solvothermal reaction to obtain an aluminum oxide hydrate intermediate;
[0033] In the embodiment of the present application, under the conditions of the first set temperature and stirring, the industrial aluminum hydroxide and the grain control agent undergo a one-step solvent thermal reaction, and the grain control agent can control the morphology, particle size and distribution of the aluminum oxide hydrate intermediate. The aluminum oxide hydrate intermediate can be a combination of one or more of boehmite, gibbsite, and gibbsite; the industrial aluminum hydroxide can be Bayer aluminum hydroxide or sintered aluminum hydroxide, and the industrial aluminum hydroxide meets the indicators: median particle size>50μm, moisture<10%.
[0034] In some embodiments, the first set temperature is 160° C. to 200° C.; and / or,
[0035] The stirring speed is 600 r / min to 1000 r / min.
[0036] In the embodiment of the present application, the "first set temperature" refers to the temperature of the solvothermal reaction, which can be 160°C to 200°C, which can fully achieve the regulation of the morphology, particle size and distribution of the alumina hydrate intermediate. Exemplarily, the temperature of the above-mentioned solvothermal reaction can be 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, etc. In addition, the time of the solvothermal reaction is not more than 4 hours, and generally speaking, the solvent can be water.
[0037] The stirring speed may be 600 r / min to 1000 r / min, which can provide a high shear force for the solvent thermal reaction, achieve uniform reaction of the reactant slurry, and avoid agglomeration. Exemplarily, the stirring speed may be 600 r / min, 650 r / min, 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min, etc.
[0038] In some embodiments, the grain control agent includes at least one of the following: boehmite, pseudo-boehmite, and activated alumina.
[0039] In some embodiments, the median particle size of the grain control agent is less than 5 μm.
[0040] In some embodiments, the weight of the grain control agent is 0.5% to 25% of the weight of the industrial aluminum hydroxide.
[0041] In the embodiments of the present application, the grain control agent can control the morphology, particle size and distribution of the alumina hydrate intermediate. The grain control agent can be a combination of one or more of boehmite, pseudo-boehmite, and activated alumina, which can promote the precipitation of crystals during the solvent thermal process, avoid agglomeration and encapsulation during the crystallization process, and optimize the particle size of the alumina hydrate intermediate.
[0042] The median particle size of the grain control agent may be less than 5 μm, so as to obtain the ideal particle size and distribution of the alumina hydrate intermediate. For example, the median particle size of the grain control agent may be 4 μm, 3 μm, 2 μm, etc.
[0043] The amount of the grain control agent added is adjusted according to the different particle sizes of industrial aluminum hydroxide. The weight of the grain control agent can be 0.5% to 25% of the weight of the industrial aluminum hydroxide, so as to obtain the particle size and distribution of the target alumina hydrate intermediate. Exemplarily, the weight of the grain control agent can be 0.5%, 0.7%, 0.9%, 1.1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, etc. of the weight of the industrial aluminum hydroxide.
[0044] In some embodiments, in the solvothermal reaction system, the concentration of the industrial aluminum hydroxide is 200 g / L to 350 g / L.
[0045] In the embodiment of the present application, in the above-mentioned solvothermal reaction system, the concentration of industrial aluminum hydroxide can be 200g / L to 350g / L, which can take into account the fluidity and production efficiency of the solvothermal reaction system and obtain the ideal particle size and distribution of the alumina hydrate intermediate. Exemplarily, the concentration of the above-mentioned industrial aluminum hydroxide can be 200g / L, 230g / L, 250g / L, 280g / L, 300g / L, 330g / L, 350g / L, etc.
[0046] Exemplarily, S1 may include: uniformly mixing industrial aluminum hydroxide and water, and then adding a grain control agent to obtain a dispersed slurry; placing the dispersed slurry in a high-speed stirring reactor, and the product obtained after the hydrothermal reaction is completed needs to be washed, separated and dried to obtain a target alumina hydrate intermediate; wherein the drying treatment can be an electric oven, a drying chamber, flash drying, spray drying, microwave drying, etc., and the drying temperature is <230°C.
[0047] S2. Under the condition of a second set temperature, the alumina hydrate intermediate is calcined to adjust the specific surface area of the calcined product to obtain γ-Al2O3.
[0048] In some embodiments, the second set temperature is 700°C to 900°C.
[0049] In the embodiment of the present application, "the second set temperature" means the roasting temperature. Under the condition of the second set temperature of 700℃ to 900℃, the alumina hydrate intermediate is activated and roasted to crystallize, so as to adjust the specific surface area of the roasted product, and obtain γ-Al2O3 with high purity, uniform particle size, high activity and high specific surface area. Exemplarily, the above-mentioned second set temperature can be 700℃, 730℃, 750℃, 780℃, 800℃, 830℃, 850℃, 870℃, 900℃, etc. The holding time of the roasting can be 2h to 4h; the roasting can be carried out in a roasting kiln, which can be one of a resistance furnace, a shuttle furnace, a push plate kiln, a stainless steel rotary kiln, a roller kiln, and a microwave heating kiln; after the roasting is completed, the roasted product is cooled and sieved, wherein the sieving can use a 40-mesh to 100-mesh screen to remove the pollutants brought into the container or kiln, and γ-Al2O3 can be obtained.
[0050] In some embodiments, the γ-Al2O3 satisfies the following indicators:
[0051] The median particle size is 5μm to 25μm, and the specific surface area is 10m2 / g~30m 2 / g, purity is>99.9%, and bulk density is 0.3g / cc~0.8g / cc.
[0052] In a second aspect, the present application provides a γ-Al2O3, wherein the γ-Al2O3 is prepared by any method described in the first aspect.
[0053] The γ-Al2O3 is realized based on the preparation method of the γ-Al2O3 mentioned above. The specific steps of the preparation method of the γ-Al2O3 can refer to the above embodiment. Since the γ-Al2O3 adopts part or all of the technical solutions of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here one by one.
[0054] In a third aspect, the present application provides a β″-Al2O3 solid electrolyte, wherein the raw material of the β″-Al2O3 solid electrolyte includes the γ-Al2O3 described in any one of the second aspects.
[0055] In the embodiment of the present application, the γ-Al2O3 meets the following indicators: the median particle size is 5 μm to 25 μm, the specific surface area is 10 m 2 / g~30m 2 / g, purity is >99.9%, and bulk density is 0.3g / cc~0.8g / cc. Therefore, γ-Al2O3 with such excellent performance can be used as the raw material of β″-Al2O3 solid electrolyte, and can make the β″-Al2O3 phase conversion rate >90%, so that the β″-Al2O3 can be better used in sodium batteries and gas sensors.
[0056] The β″-Al2O3 solid electrolyte is realized based on the above-mentioned γ-Al2O3. The specific indicators of the γ-Al2O3 can refer to the above-mentioned embodiments. Since the β″-Al2O3 solid electrolyte system adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.
[0057] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.
[0058] Example 1
[0059] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with deionized water to prepare a slurry concentration (aluminum hydroxide concentration) of 320g / L (the median particle size of aluminum hydroxide is 85.9μm), adding 10%wt-AH boehmite (median particle size is 1.2μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 800r / min, and reacting at 200°C for 1 hour. After washing and removing impurities, the reaction slurry is dried in an oven at 150°C to obtain a high-purity boehmite intermediate.
[0060] The intermediate was placed in a resistance furnace and calcined at 800°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 13.8 μm and a specific surface area of 19.8 m 2 / g, Al2O3 purity 99.92%, bulk density 0.61g / cc.
[0061] For example, Figure 2 This is a SEM image (low magnification) of γ-Al2O3 provided in Example 1 of the present application; see Figure 2 , indicating that the particle size of γ-Al2O3 obtained in Example 1 is between 5 μm and 25 μm; Figure 3 This is a SEM image (high magnification) of γ-Al2O3 provided in Example 1 of the present application; see Figure 3 , indicating that the γ-Al2O3 obtained in Example 1 is a rhombus-shaped agglomerate; Figure 4 This is an XRD diagram of γ-Al2O3 provided in Example 1 of the present application; see Figure 4 , indicating that the crystal form of the target product obtained in Example 1 is γ-Al2O3.
[0062] Example 2
[0063] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with reverse osmosis water to prepare a slurry concentration of 320g / L (the median particle size of aluminum hydroxide is 85.9μm), adding 1.0%wt-AH boehmite (median particle size is 1.2μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 800r / min, and reacting at 180°C for 2 hours. After washing and removing impurities, the reaction slurry is dried at 140°C in a microwave oven to obtain an intermediate of a mixture of gibbsite and diaspore.
[0064] The intermediate was placed in a resistance furnace and calcined at 850°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 22.5 μm and a specific surface area of 18.2 m 2 / g, Al2O3 purity 99.91%, bulk density 0.65g / cc.
[0065] Example 3
[0066] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 5.0% with high-purity water to prepare a slurry concentration of 200g / L (the median particle size of aluminum hydroxide is 101.4μm), adding 20%wt-AH pseudo-boehmite (median particle size is 2.6μm), fully stirring and placing in a reactor, the filling amount is 75%, the stirring speed is 1000r / min, and the reaction is carried out at 160°C for 4 hours. After washing and removing impurities, the reaction slurry is dried in an oven at 100°C to obtain an intermediate of a mixture of diaspore and gibbsite.
[0067] The intermediate was placed in a shuttle furnace and calcined at 700°C for 4 hours. After natural cooling, it was passed through a 60-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 7.7 μm and a specific surface area of 28.4 m 2 / g, Al2O3 purity 99.91%, bulk density 0.36g / cc.
[0068] Example 4
[0069] A preparation method of γ-Al2O3 specifically comprises: mixing sintered aluminum hydroxide with a water content of 2.3% with deionized water to prepare a slurry concentration of 250g / L (the median particle size of aluminum hydroxide is 70.2μm), adding 5.0%wt-AH activated alumina (median particle size is 4.3μm), fully stirring and placing in a reactor, the filling amount is 75%, the stirring speed is 600r / min, and the reaction is carried out at 190°C for 2 hours. After washing and removing impurities, the reaction slurry is dried in an oven at 150°C to obtain a high-purity boehmite intermediate.
[0070] The intermediate was placed in a shuttle furnace and calcined at 900°C for 3 hours. After natural cooling, it was passed through a 60-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 23.6 μm and a specific surface area of 15.9 m 2 / g, Al2O3 purity 99.96%, bulk density 0.65g / cc.
[0071] Example 5
[0072] A preparation method of γ-Al2O3 specifically comprises: mixing sintered aluminum hydroxide with a water content of 0.3% with deionized water to prepare a slurry concentration of 350g / L (the median particle size of the aluminum hydroxide is 56.1μm), adding 0.5%wt-AH boehmite (median particle size is 0.8μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 700r / min, and reacting at 195°C for 3 hours. After washing and removing impurities, the reaction slurry is dried in a microwave oven to obtain a high-purity boehmite intermediate.
[0073] The intermediate was placed in a resistance furnace and calcined at 800°C for 2 hours. After natural cooling, it was passed through a 100-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 10.4 μm and a specific surface area of 23.2 m 2 / g, Al2O3 purity 99.94%, bulk density 0.38g / cc.
[0074] Example 6
[0075] A preparation method of γ-Al2O3 specifically comprises: mixing sintered aluminum hydroxide with a water content of 1.4% with distilled water to prepare a slurry concentration of 200g / L (the median particle size of aluminum hydroxide is 95.6μm), adding 20%wt-AH boehmite (median particle size is 2.4μm), stirring well and placing in a reactor, with a filling amount of 78%, a stirring speed of 800r / min, and reacting at 180°C for 4 hours. After washing and removing impurities, the reaction slurry is dried at 100°C in an oven to obtain a mixture intermediate of gibbsite and diaspore.
[0076] The intermediate was placed in a resistance furnace and calcined at 750°C for 4 hours. After natural cooling, it was passed through a 60-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 9.7 μm and a specific surface area of 17.7 m 2 / g, Al2O3 purity 99.93%, bulk density 0.41g / cc.
[0077] Example 7
[0078] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 5.0% with reverse osmosis water to prepare a slurry concentration of 300g / L (the median particle size of the aluminum hydroxide is 81.6μm), adding 5.0%wt-AH boehmite (median particle size is 2.4μm), stirring well and placing in a reactor, with a filling amount of 75%, a stirring speed of 800r / min, and reacting at 195°C for 2 hours. After washing and removing impurities, the reaction slurry is dried by controlling the inlet temperature of a flash dryer to 220°C to obtain a high-purity boehmite intermediate.
[0079] The intermediate was placed in a push plate furnace and calcined at 900°C for 4 hours. After natural cooling, it was passed through a 40-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 12.1 μm and a specific surface area of 16.3 m 2 / g, Al2O3 purity 99.92%, bulk density 0.57g / cc.
[0080] Example 8
[0081] A preparation method of γ-Al2O3 specifically comprises: mixing sintered aluminum hydroxide with a water content of 1.1% with reverse osmosis water to prepare a slurry concentration of 280g / L (the median particle size of aluminum hydroxide is 75.1μm), adding 5.0%wt-AH pseudo-boehmite (median particle size is 2.6μm), fully stirring and placing in a reactor, the filling amount is 75%, the stirring speed is 800r / min, and the reaction is carried out at 200°C for 1 hour. After washing and removing impurities, the reaction slurry is dried by controlling the outlet temperature of a flash dryer to 220°C to obtain a high-purity boehmite intermediate.
[0082] The intermediate was placed in a push plate furnace and calcined at 850°C for 4 hours. After natural cooling, it was passed through a 40-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 9.6 μm and a specific surface area of 20.1 m 2 / g, Al2O3 purity 99.95%, bulk density 0.36g / cc.
[0083] Comparative Example 1
[0084] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with deionized water to prepare a slurry concentration of 320 g / L (the median particle size of the aluminum hydroxide is 85.9 μm), fully stirring and placing in a reaction kettle, with a filling amount of 80%, a stirring speed of 800 r / min, and reacting at 200° C. for 1 hour. After washing and removing impurities, the reaction slurry is dried in an oven at 150° C. to obtain a boehmite intermediate.
[0085] The intermediate was placed in a resistance furnace and calcined at 800°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 74.2 μm and a specific surface area of 11.6 m 2 / g, Al2O3 purity 99.83%, bulk density 0.82g / cc.
[0086] Comparative Example 2
[0087] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with deionized water to prepare a slurry concentration of 320g / L (the median particle size of the aluminum hydroxide is 85.9μm), adding 10%wt-AH boehmite (median particle size is 1.2μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 800r / min, and reacting at 210°C for 1 hour. After washing and removing impurities, the reaction slurry is dried in an oven at 150°C to obtain a high-purity boehmite intermediate.
[0088] The intermediate was placed in a resistance furnace and calcined at 800°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 28.6 μm and a specific surface area of 39.7 m 2 / g, Al2O3 purity 99.85%, bulk density 0.66g / cc.
[0089] Comparative Example 3
[0090] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with deionized water to prepare a slurry concentration of 320g / L (the median particle size of the aluminum hydroxide is 85.9μm), adding 10%wt-AH boehmite (median particle size is 1.2μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 800r / min, and reacting at 200°C for 1 hour. After washing and removing impurities, the reaction slurry is dried in an oven at 150°C to obtain a high-purity boehmite intermediate.
[0091] The intermediate was placed in a resistance furnace and calcined at 600°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 16.2 μm and a specific surface area of 86.1 m 2 / g, Al2O3 purity 99.85%, bulk density 0.39g / cc.
[0092] Comparative Example 4
[0093] A preparation method of γ-Al2O3 specifically comprises: mixing Bayer aluminum hydroxide with a water content of 4.6% with deionized water to prepare a slurry concentration of 320g / L (the median particle size of the aluminum hydroxide is 85.9μm), adding 30%wt-AH boehmite (median particle size is 1.2μm), stirring well and placing in a reactor, with a filling amount of 80%, a stirring speed of 800r / min, and reacting at 200°C for 1 hour. After washing and removing impurities, the reaction slurry is dried in an oven at 150°C to obtain a high-purity boehmite intermediate.
[0094] The intermediate was placed in a resistance furnace and calcined at 800°C for 2 hours. After natural cooling, it was passed through an 80-mesh stainless steel sieve to obtain the target product. The product was γ-Al2O3 with a median particle size of 3.9 μm and a specific surface area of 48.8 m 2 / g, Al2O3 purity 99.88%, bulk density 0.29g / cc.
[0095] The products obtained in each embodiment and comparative example were characterized and tested, and the results are shown in Table 1.
[0096] Table 1 Test results of the products obtained in various embodiments and comparative examples
[0097]
[0098]
[0099] The γ-Al2O3 prepared in Examples 1 to 8 and Comparative Examples 1 to 4 was used to prepare β″-Al2O3 solid electrolyte. The β″-Al2O3 phase conversion rate is shown in Table 2.
[0100]
[0101] As shown in Table 1, the γ-Al2O3 prepared in the present embodiment meets the following indicators: the median particle size is 5 μm to 25 μm, the specific surface area is 10 m 2 / g~30m 2 / g, purity is >99.9%, and bulk density is 0.3g / cc~0.8g / cc. In comparative example 1, no grain control agent is used; the hydrothermal reaction temperature in comparative example 2 is too high; the calcination temperature in comparative example 3 is too low; the amount of grain control agent used in comparative example 4 is too high, and combined with Table 2, it is shown that the indicators of comparative examples 1 to 4 are not within the scope of the embodiments of the present application, which affects the application as a raw material for β″-Al2O3 solid electrolyte. It can be seen from Table 2 that the γ-Al2O3 prepared in the embodiment of the present application can be used as a raw material for β″-Al2O3 solid electrolyte, and the β″-Al2O3 phase conversion rate is >90%.
[0102] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:
[0103] (1) The present invention uses low-cost industrial aluminum hydroxide as an aluminum source, obtains an aluminum oxide hydrate intermediate by a one-step solvothermal method using a grain regulator, and then obtains a γ-Al2O3 product with high activity by activation roasting and crystallization, which can be used as a raw material for β″-Al2O3 solid electrolyte ceramics for sodium salt batteries;
[0104] (2) The embodiment of the present application adopts a low-cost one-step hydrothermal method of aluminum hydroxide combined with a roasting process, and the obtained product is γ-alumina with a purity of >99.9%, uniform particle size and high activity; the γ-alumina can be used as a raw material for β″-Al2O3 solid electrolyte ceramics; the preparation method of the γ-alumina has the advantages of simple production process, low cost, and easy industrialization.
[0105] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A method for preparing γ-Al2O3, characterized in that: The method comprises: Under the conditions of a first set temperature and stirring, industrial aluminum hydroxide and a grain control agent are subjected to a solvothermal reaction to obtain an aluminum oxide hydrate intermediate; Under the condition of a second set temperature, the alumina hydrate intermediate is calcined to adjust the specific surface area of the calcined product to obtain γ-Al2O3.
2. The method according to claim 1, characterized in that: The first set temperature is 160° C. to 200° C.; and / or, The stirring speed is 600 r / min to 1000 r / min.
3. The method according to claim 1, characterized in that The grain control agent includes at least one of the following: boehmite, pseudo-boehmite, and activated alumina.
4. The method according to claim 1, characterized in that: The median particle size of the grain control agent is less than 5 μm.
5. The method according to claim 1, 3 or 4, characterized in that: The weight of the grain control agent is 0.5% to 25% of the weight of the industrial aluminum hydroxide.
6. The method according to claim 1, characterized in that In the solvent thermal reaction system, the concentration of the industrial aluminum hydroxide is 200 g / L to 350 g / L.
7. The method according to claim 1, characterized in that The second set temperature is 700°C to 900°C.
8. The method according to claim 1, characterized in that The γ-Al2O3 meets the following indicators: The median particle size is 5μm to 25μm, and the specific surface area is 10m 2 / g~30m 2 / g, purity is>99.9%, and bulk density is 0.3g / cc~0.8g / cc.
9. A γ-Al2O3, characterized in that The γ-Al2O3 is prepared by the method described in any one of claims 1 to 8.
10. A β"-Al2O3 solid electrolyte, characterized in that: The raw material of the β"-Al2O3 solid electrolyte includes the γ-Al2O3 described in claim 9.