CN115215640A - Method for synthesizing high-purity mullite powder - Google Patents
Method for synthesizing high-purity mullite powder Download PDFInfo
- Publication number
- CN115215640A CN115215640A CN202110407414.6A CN202110407414A CN115215640A CN 115215640 A CN115215640 A CN 115215640A CN 202110407414 A CN202110407414 A CN 202110407414A CN 115215640 A CN115215640 A CN 115215640A
- Authority
- CN
- China
- Prior art keywords
- solution
- hours
- purity
- powder
- deionized water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000843 powder Substances 0.000 title claims abstract description 86
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 title claims abstract description 60
- 229910052863 mullite Inorganic materials 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 27
- 230000002194 synthesizing effect Effects 0.000 title claims abstract description 13
- 239000000243 solution Substances 0.000 claims abstract description 93
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000008367 deionised water Substances 0.000 claims abstract description 35
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 35
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 32
- 238000003756 stirring Methods 0.000 claims abstract description 30
- 238000005303 weighing Methods 0.000 claims abstract description 30
- 239000002243 precursor Substances 0.000 claims abstract description 29
- 239000011240 wet gel Substances 0.000 claims abstract description 27
- 238000001035 drying Methods 0.000 claims abstract description 26
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 16
- 239000010703 silicon Substances 0.000 claims abstract description 16
- 238000001354 calcination Methods 0.000 claims abstract description 14
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 238000003760 magnetic stirring Methods 0.000 claims abstract description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000011259 mixed solution Substances 0.000 claims abstract description 4
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical group CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims description 55
- XNDZQQSKSQTQQD-UHFFFAOYSA-N 3-methylcyclohex-2-en-1-ol Chemical group CC1=CC(O)CCC1 XNDZQQSKSQTQQD-UHFFFAOYSA-N 0.000 claims description 51
- 238000010438 heat treatment Methods 0.000 claims description 24
- 238000000498 ball milling Methods 0.000 claims description 22
- 238000007873 sieving Methods 0.000 claims description 17
- 239000006185 dispersion Substances 0.000 claims description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 238000009826 distribution Methods 0.000 claims description 3
- 238000001308 synthesis method Methods 0.000 claims 2
- 238000002156 mixing Methods 0.000 description 25
- 239000002994 raw material Substances 0.000 description 23
- 239000000499 gel Substances 0.000 description 12
- 239000000919 ceramic Substances 0.000 description 11
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 8
- 238000002834 transmittance Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 235000019441 ethanol Nutrition 0.000 description 6
- 238000005245 sintering Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000003786 synthesis reaction Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 238000003980 solgel method Methods 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006068 polycondensation reaction Methods 0.000 description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- JLDSOYXADOWAKB-UHFFFAOYSA-N aluminium nitrate Chemical compound [Al+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O JLDSOYXADOWAKB-UHFFFAOYSA-N 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000010923 batch production Methods 0.000 description 2
- 239000004202 carbamide Substances 0.000 description 2
- 238000000445 field-emission scanning electron microscopy Methods 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000004876 x-ray fluorescence Methods 0.000 description 2
- 238000004910 27Al NMR spectroscopy Methods 0.000 description 1
- 238000005133 29Si NMR spectroscopy Methods 0.000 description 1
- 241000759909 Camptotheca Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000004100 electronic packaging Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000007794 irritation Effects 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000643 oven drying Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
- C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
- C04B35/185—Mullite 3Al2O3-2SiO2
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/624—Sol-gel processing
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B2235/9646—Optical properties
Abstract
The invention relates to a method for synthesizing high-purity mullite powder, which comprises the following steps: according to the molar ratio of the aluminum element to the silicon element of 2.5-5: 1, weighing inorganic aluminum salt and a silicon source; adding inorganic aluminum salt into deionized water, adding a silicon source into a mixed solution of the deionized water and absolute ethyl alcohol, and simultaneously stirring for one time to respectively obtain a first solution and a second solution; the primary stirring mode is magnetic stirring, the rotating speed is 400-800 r/min, and the time is 11-13 hours; dripping the first solution into the second solution, and continuing stirring for the second time to obtain a third solution, wherein the second stirring mode is magnetic stirring, the rotating speed is 500-1000 r/min, and the time is 11-13 hours; drying the third solution at 50-70 ℃ for 12-24 hours to obtain wet gel; drying the wet gel at 110-150 ℃ for 3-24 hours to obtain a precursor; and calcining the precursor for 3 to 6 hours.
Description
Technical Field
The invention relates to a method for synthesizing high-purity mullite powder, in particular to a method for synthesizing high-purity mullite powder by a wet chemical method, and belongs to the field of ceramic powder synthesis.
Background
Mullite has high thermal stability, high thermal conductivity, low linear expansion coefficient, high creep resistance and good corrosion resistance, and is widely applied to the field of refractory materials. Meanwhile, mullite has the properties of low dielectric constant and loss, good infrared transmittance and the like, has wide application prospects in the fields of infrared windows, fairings, electronic packaging and the like, and has very high requirements on the purity, granularity and sintering performance of powder in the fields, but natural mullite in nature is few, and artificially synthesized mullite and the existing commercial mullite have low purity and poor sintering activity, and cannot meet the application requirements in high-end fields. Therefore, a method for synthesizing mullite with excellent synthesis performance is to be found.
The sol-gel method is also used to synthesize mullite powder as a method for synthesizing high purity powder. At present, researchers have prepared high-purity mullite powder by using a sol-gel method. Camptotheca et al (proceedings of inorganic materials, 2001, 16 (3), 555-558) prepared a mullite precursor from tetraethoxysilane and aluminum chloride, and calcined at 1250 deg.C to obtain mullite powder; the patent "method for preparing nano mullite powder by sol-gel-hydrothermal method" (CN 101700980A) uses aluminium nitrate and ethyl orthosilicate as raw materials, and prepares mullite powder by calcining by combining the hydrolytic sol-gel method with the hydrothermal method, and hydrochloric acid is required to be added in the methods, and has strong volatility and corrosivity. Jaymes et al (New aqueous mullite synthesis: structural student by 27Al and 29Si NMR spectroscopy. J Eur Ceram Soc 16) synthesize mullite powder at 980 ℃ by adding urea, which has strong irritation and is harmful to human body. Therefore, most of the prior art needs to add some hydrochloric acid and urea, which causes over-high cost and environmental pollution, and in the process of preparing mullite powder, the problems of long preparation period, high cost, inconvenience for batch production and the like exist.
Disclosure of Invention
The invention aims to provide a sol-gel method for synthesizing high-purity mullite powder without other additives and with a short period.
In a first aspect, the present invention provides a method for synthesizing high purity mullite powder, comprising:
according to the molar ratio of the aluminum element to the silicon element of 2.5-5: 1, weighing inorganic aluminum salt and a silicon source; adding inorganic aluminum salt into deionized water, adding a silicon source into a mixed solution of the deionized water and absolute ethyl alcohol, and simultaneously stirring for one time to respectively obtain a first solution and a second solution; the primary stirring mode is magnetic stirring, the rotating speed is 400-800 r/min, the time is 11-13 hours, and the magnetic stirring is preferably 12 hours; dripping the first solution into the second solution, and continuing to stir for the second time to obtain a third solution, wherein the second stirring mode is magnetic stirring, the rotating speed is 500-1000 r/min, the time is 11-13 hours, and the magnetic stirring is preferably 12 hours; drying the third solution at 50-70 ℃ for 12-24 hours to obtain wet gel; drying the wet gel at 110-150 ℃ for 3-24 hours to obtain a precursor; and calcining the precursor for 3-6 hours to obtain the high-purity mullite powder.
The mixing mode of the first stirring and the second stirring is to achieve the mixing of nanometer scale, if the stirring time is too short, the components are not uniform, even the mixing of nanometer size can not be achieved, and the uniformity and the sintering activity of subsequent calcined powder are influenced.
Preferably, the inorganic aluminum salt is Aluminum Nitrate Nonahydrate (ANN) having a purity of at least AR (AR is an analytical purity of 99.7%), and the silicon source is tetraethyl orthosilicate (TEOS) having a purity of at least 99.99% or more.
Preferably, the molar ratio of ANN to TEOS is (2.76-4.67): 1, preferably 3.88; the powder sintered ceramic obtained according to the proportion can form pure-phase mullite ceramic, and has good infrared transmittance which is 60-70% at the position of 4 mu m.
Preferably, the ratio of inorganic aluminum salt in the first solution: the mass ratio of the deionized water is 1.5-2.5: 1, preferably 2.
Among them, ethyl orthosilicate is in weak acid (pH = 3-5) solution hydrolysis polycondensation speed is fast, easy to form gel, but at this moment, the gel is not easy to mix with aluminum nitrate nonahydrate solution, therefore, only adding ethanol and little water into ethyl orthosilicate single solution makes it hydrolyze slowly without polycondensation reaction. The solution is weakly acidic by utilizing the self-hydrolysis of the aluminum nitrate, and under the condition, the good gel speed can be kept under the condition of ensuring the uniformity of the sol, and meanwhile, spherical powder is easier to form.
Preferably, the ratio of silicon source: deionized water: the mass ratio of the absolute ethyl alcohol is 1:0.3 to 0.7:2.5 to 3.5, preferably 2; under the condition of the mass ratio, the hydrolysis speed of the tetraethoxysilane can be controlled, the occurrence of gel caused by a large amount of polycondensation reaction is avoided, and the mixing with the aluminum nitrate solution in the later step is facilitated.
Preferably, the speed of dripping the first solution into the second solution is 2-4 ml/min. At this rate, it is ensured that the two solutions are mixed uniformly. The uniformity of the solution mixing can affect the uniformity of the powder components, so that the sintering activity of the powder is greatly affected, and the uneven powder is not beneficial to the sintering process of ceramics.
Preferably, the calcination temperature is 1000-1300 ℃; the heating rate is 2-4 ℃/min.
Preferably, after calcination, the calcined product is further subjected to ball milling dispersion treatment, wherein the rotation speed of the ball milling dispersion treatment is 200-300 r/min, the treatment time is 12-24 hours, the balls are alumina balls, the medium is absolute ethyl alcohol, and the mass ratio of the ball: powder: 5-7 of absolute ethyl alcohol: 1:1 to 1.4.
Preferably, drying and sieving the mullite powder subjected to ball milling dispersion treatment, and then carrying out heat treatment at 800-1000 ℃ for 2-4 hours to obtain high-purity mullite powder with uniform particle size distribution; preferably, the drying is drying in an oven at 60 ℃ for 12 hours, and the sieving is 200-mesh sieving.
Preferably, the molar ratio of ANN to TEOS is (2.76-4.67) 1, preferably 3.88; the powder sintered ceramic obtained according to the proportion can form pure-phase mullite ceramic, and has good infrared transmittance which is 60-70% at 4 mu m.
Compared with the prior art, the method for preparing the high-purity mullite powder has the following advantages:
(1) The invention does not need additive, has simple process and is convenient for batch production;
(2) The period for synthesizing the powder is short, only 3-5 days are needed, and the powder synthesis efficiency is obviously improved;
(3) The purity of the mullite powder prepared by the invention is over 99.5 percent through the analysis of X-ray fluorescence spectrum.
Drawings
FIG. 1 is an XRD pattern of mullite powder synthesized in accordance with example 1 of the present invention, which shows that the precursor is amorphous until calcined at 1200 deg.C, and is transformed into crystalline mullite at 1200 deg.C;
FIG. 2 is a FESEM photograph of mullite powder synthesized in example 1 of the present invention, which shows that the powder is more uniform and the particles are finer;
FIG. 3 shows XRF analysis results of mullite powder synthesized in example 1 of the present invention, indicating that the powder purity is above 99.5%;
FIG. 4 shows the infrared transmittance of the mullite transparent ceramic prepared by synthesizing the mullite powder in example 9 of the present invention, wherein the infrared transmittance at 4 μm is 65%.
Detailed Description
The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive.
The method for synthesizing the high-purity mullite powder is exemplarily described as follows:
inorganic aluminum salt and a silicon source are used as raw materials, and the raw materials are weighed according to the molar ratio of aluminum element to silicon element of 2.5-5 to prepare a first solution and a second solution respectively. The inorganic aluminum salt can adopt aluminum nitrate nonahydrate, and the silicon source can adopt ethyl orthosilicate; wherein, the aluminum nitrate nonahydrate has analytical purity, and the purity of the tetraethoxysilane is more than 99 percent. The molar ratio of ANN to TEOS may be (2.76-4.67): 1, preferably 3.88; the powder sintered ceramic obtained according to the proportion can form pure-phase mullite ceramic, and has good infrared transmittance which is 60-70% at 4 mu m.
In one detailed example, aluminum nitrate nonahydrate is dissolved in deionized water with stirring to obtain an aluminum nitrate solution, the concentration of aluminum nitrate is determined chemically, and an amount of water is added to obtain a target concentration of aluminum nitrate solution as the first solution. Although ANN (aluminum nitrate nonahydrate) contains crystal water and can form a mixed solution with ethanol, the dissolving process is extremely long, the process time is prolonged, and aluminum nitrate is extremely difficult to dissolve in ethanol and has better solubility in water, so deionized water is used as a solvent for the ANN. Wherein, the mass ratio of the aluminum nitrate nonahydrate to the deionized water can be 2. After mixing, magnetic stirring can be adopted, the rotating speed is 400-800 r/min, the time can be 12 hours, and the length-diameter ratio of a used rotor can be 4-6: 1.
in a detailed example, deionized water and ethanol are added into the ethyl orthosilicate to be mixed and stirred so as to be hydrolyzed fully, and ethyl orthosilicate solution is obtained as a second solution. The solvent used by the TEOS in the invention is a mixed solvent of water and ethanol, the TEOS is easily dissolved in ethanol and is not easily dissolved in water, and the purpose of adding water is to hydrolyze the TEOS before mixing with the aluminum nitrate solution, so that the mixing time of the aluminum nitrate solution and the TEOS is reduced. Wherein the mass ratio of the ethyl orthosilicate, the deionized water and the absolute ethyl alcohol can be 1.3-0.7. After mixing, magnetic stirring can be adopted, the rotating speed is 400-800 r/min, the time can be 12 hours, and the length-diameter ratio of a used rotor can be 4-6: 1.
and dripping the first solution into the second solution and uniformly mixing to obtain sol serving as a third solution. Wherein, the dropping speed can be 2-4 ml/min. Wherein, too short stirring time can cause the nonuniformity of components and even fail to achieve the mixing of nanometer size, thereby influencing the uniformity of the subsequent calcined powder. Therefore, the stirring time is too long or too short, which has adverse effects, and 11 to 13 hours, preferably 12 hours, is selected as the most suitable time.
And putting the third solution into a low-temperature oven to react for 12 to 24 hours at the temperature of between 50 and 70 ℃ to obtain wet gel. The wet gel needs to be dried until the container is tilted thirty degrees without the gel flowing. And then the wet gel is put into a high-temperature oven to be dried for 3 to 24 hours at the temperature of between 110 and 150 ℃ to obtain a yellow precursor. In the invention, more water is added into TEOS, the hydrolysis process of TEOS is faster, so that the temperature can be properly raised to cause the TEOS to gel, and if the temperature is too high, the TEOS can cause the TEOS to be uneven. After the gel is formed, the gel needs to be dried to become dry gel, the drying process is essentially a water transportation process, generally, the higher the drying temperature is, the more water is evaporated in unit time, the better the effect is, but when the temperature exceeds 150 ℃ in actual operation, the gel runs out of a container along with water vapor, so that the pollution of an oven is caused; also, excessive temperatures can cause uneven moisture transport across and within the gel resulting in uneven composition. Therefore, the temperature of more than or equal to 110 ℃ and less than or equal to 150 ℃ is selected for drying. The method for preparing the gel by two steps reduces the drying temperature and improves the powder synthesis efficiency under the condition of ensuring the sintering activity of the powder.
And putting the yellow precursor into a muffle furnace for calcination treatment. The calcination temperature may be 1000 to 1300 ℃, preferably 1200 ℃, the calcination time may be 3 to 6 hours. The heating rate of the calcination can be 2-4 ℃/min.
And performing ball milling dispersion treatment on the calcined powder to obtain the high-purity mullite powder. The rotation speed of ball milling dispersion treatment can be 200-300 r/min, preferably 250 r/min, the treatment time can be 12-24 hours, the ball milling balls are alumina balls, the ball milling medium is absolute ethyl alcohol, the ball: powder: 5-7 of absolute ethyl alcohol: 1:1 to 1.4. Drying and sieving the mullite powder subjected to ball milling dispersion treatment, and then carrying out heat treatment at 800-1000 ℃ for 2-4 h to obtain the high-purity mullite powder with uniform particle size distribution. The heat treatment here is to remove impurities introduced in the previous step. As an example, the drying is oven drying at 60 ℃ for 12h. The sieving is 200 mesh sieving.
XRF results of the mullite powder prepared according to the invention show that the alumina content and the proportion of the added raw materials are consistent; the molar content of alumina in the mullite powder is 58 to 70 percent according to the proportion of the added raw materials; the alumina content is the composition of mullite written as (xAl) 2 O 3 ·ySiO 2 ) Wherein x is the ratio of (x + y).
The present invention will be described in further detail with reference to examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art in light of the foregoing description are intended to be included within the scope of the invention.
Example 1
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water =2:1, mixing, and magnetically stirring for 12 hours to fully hydrolyze to obtain a first solution. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 2.76. And (3) dripping the first solution into the second solution at the flow rate of 2 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in a 60 ℃ oven to dry for 12 hours, and the solution became a wet gel. And putting the wet gel into an oven at 150 ℃ to continuously dry for 3 hours to obtain a yellow precursor. And (3) placing the yellow precursor into a muffle furnace, keeping the temperature at 1200 ℃ for 3 hours, and heating at the rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder with the particle size of 300-700nm.
The XRD chart in fig. 1 shows that the precursor was amorphous until the calcination at 1200 c and transformed to crystalline mullite at 1200 c; the FESEM plot in fig. 2 shows that the powder is more uniform and the particles are finer; powder purity was determined by XRF and the results are shown in figure 3.
Example 2
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water =2:1, mixing, and magnetically stirring for 12 hours to fully hydrolyze to obtain a first solution. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3. And (3) dripping the first solution into the second solution at the flow rate of 2 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in an oven at 60 ℃ for 12 hours to dry the solution to a wet gel. And putting the wet gel into an oven at 150 ℃ to be continuously dried for 3 hours to obtain a yellow precursor. And (3) putting the yellow precursor into a muffle furnace, and keeping the temperature at 1200 ℃ for 3 hours at a heating rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at the temperature of 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at the temperature of 800 ℃ to obtain the high-purity mullite powder.
Example 3
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3.40. And (3) dripping the first solution into the second solution at the flow rate of 2 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in an oven at 60 ℃ for 12 hours to dry the solution to a wet gel. And putting the wet gel into an oven at 150 ℃ to continuously dry for 3 hours to obtain a yellow precursor. And (3) placing the yellow precursor into a muffle furnace, keeping the temperature at 1200 ℃ for 3 hours, and heating at the rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at the temperature of 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at the temperature of 800 ℃ to obtain the high-purity mullite powder.
Example 4
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3.88, mixing according to the mass ratio of TEOS to deionized water to absolute ethyl alcohol = 2. And (3) dripping the first solution into the second solution at the flow rate of 2 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in an oven at 60 ℃ for 12 hours to dry the solution to a wet gel. And putting the wet gel into an oven at 150 ℃ to be continuously dried for 3 hours to obtain a yellow precursor. And (3) putting the yellow precursor into a muffle furnace, and keeping the temperature at 1200 ℃ for 3 hours at a heating rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder, wherein the purity of the powder is 99.5% by X-ray fluorescence spectrum analysis.
Example 5
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water =2:1, mixing, and magnetically stirring for 12 hours to fully hydrolyze to obtain a first solution. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 4.67. And (3) dripping the first solution into the second solution at the flow rate of 2 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in an oven at 60 ℃ for 12 hours to dry the solution to a wet gel. And putting the wet gel into an oven at 150 ℃ to continuously dry for 3 hours to obtain a yellow precursor. And (3) putting the yellow precursor into a muffle furnace, and keeping the temperature at 1200 ℃ for 3 hours at a heating rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at the temperature of 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at the temperature of 800 ℃ to obtain the high-purity mullite powder.
Example 6
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3. And (3) dropwise adding the first solution into the second solution at the flow rate of 2 ml/min, and after mixing, continuing stirring for 12 hours by magnetic force to obtain a third solution. The third solution was dried in an oven at 60 ℃ for 12 hours, and the solution became a wet gel. And putting the wet gel into a 110 ℃ oven to be dried for 24 hours continuously to obtain a yellow precursor. And (3) putting the yellow precursor into a muffle furnace, and keeping the temperature at 1200 ℃ for 3 hours at a heating rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder.
Example 7
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3. And (3) dropwise adding the first solution into the second solution at the flow rate of 3 ml/min, and after mixing, continuing stirring for 12 hours by magnetic force to obtain a third solution. The third solution was placed in an oven at 60 ℃ for 12 hours to dry the solution to a wet gel. And putting the wet gel into an oven at 150 ℃ to be continuously dried for 3 hours to obtain a yellow precursor. And (3) placing the yellow precursor into a muffle furnace, keeping the temperature at 1200 ℃ for 3 hours, and heating at the rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder.
Example 8
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3. And (3) dripping the first solution into the second solution at the flow rate of 3 ml/min, mixing, and then continuing to stir for 12 hours by magnetic force to obtain a third solution. The third solution was placed in a 60 ℃ oven to dry for 12 hours, and the solution became a wet gel. And putting the wet gel into a 110 ℃ oven to be continuously dried for 24 hours to obtain a yellow precursor. And (3) putting the yellow precursor into a muffle furnace, and keeping the temperature at 1200 ℃ for 3 hours at a heating rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder.
Example 9
The purity of the raw material ANN is analytically pure, and the purity of the raw material TEOS is 99%. Weighing a certain amount of ANN, weighing deionized water according to a mass ratio of ANN to deionized water = 2. Weighing a certain amount of TEOS according to the molar ratio of ANN to TEOS of 3.88, mixing according to the mass ratio of TEOS to deionized water to absolute ethyl alcohol = 2. And (3) dropwise adding the first solution into the second solution at the flow rate of 2 ml/min, and after mixing, continuing stirring for 12 hours by magnetic force to obtain a third solution. The third solution was placed in a 60 ℃ oven to dry for 12 hours, and the solution became a wet gel. And putting the wet gel into an oven at 150 ℃ to be continuously dried for 3 hours to obtain a yellow precursor. And (3) placing the yellow precursor into a muffle furnace, keeping the temperature at 1200 ℃ for 3 hours, and heating at the rate of 2 ℃/min to obtain powder. And finally, performing ball milling on the powder for 24 hours at the rotating speed of 200-300 r/min, drying in an oven at 60 ℃ for 12 hours, sieving by a 200-mesh sieve, and performing heat treatment at 800 ℃ to obtain the high-purity mullite powder. The obtained high-purity mullite powder is sintered for 6 hours under the vacuum condition of 1750 ℃ after being subjected to dry pressing forming and cold isostatic pressing forming, and the mullite infrared transparent ceramic is obtained. The infrared transmittance of the obtained mullite infrared transparent ceramic is shown in figure 4, and the infrared transmittance at the position of 4 mu m reaches 65 percent.
Claims (8)
1. A method for synthesizing high-purity mullite powder is characterized by comprising the following steps:
according to the molar ratio of the aluminum element to the silicon element of 2.5-5: 1, weighing inorganic aluminum salt and a silicon source;
adding inorganic aluminum salt into deionized water, adding a silicon source into a mixed solution of the deionized water and absolute ethyl alcohol, and simultaneously stirring for one time to respectively obtain a first solution and a second solution; the primary stirring mode is magnetic stirring, the rotating speed is 400-800 r/min, and the time is 11-13 hours;
dripping the first solution into the second solution, and continuing stirring for the second time to obtain a third solution, wherein the second stirring mode is magnetic stirring, the rotating speed is 500-1000 r/min, and the time is 11-13 hours;
drying the third solution at 50-70 ℃ for 12-24 hours to obtain wet gel;
drying the wet gel at 110-150 ℃ for 3-24 hours to obtain a precursor; and
and calcining the precursor for 3-6 hours to obtain the high-purity mullite powder.
2. The method of claim 1, wherein the inorganic aluminum salt is aluminum nitrate nonahydrate and has a purity of at least AR; the silicon source is tetraethoxysilane with the purity of at least more than 99.99 percent; preferably, the molar ratio of aluminum nitrate nonahydrate to ethyl orthosilicate is (2.76-4.67): 1.
3. The method according to claim 1 or 2, wherein the mass ratio of the inorganic aluminum salt to the deionized water in the first solution is 1.5-2.5: 1.
4. the method of any one of claims 1 to 3, wherein the second solution comprises the silicon source, the deionized water and the absolute ethyl alcohol in a mass ratio of 1:0.3 to 0.7:2.5 to 3.5.
5. The method according to any one of claims 1 to 4, wherein the first solution is dropped into the second solution at a rate of 2 to 4 ml/min.
6. The process according to any one of claims 1 to 5, characterized in that the temperature of the calcination is comprised between 1000 and 1300 ℃; the temperature rise rate of the calcination is 2-4 ℃/min.
7. The synthesis method according to any one of claims 1 to 6, characterized in that after calcination, the calcined product is further subjected to ball milling dispersion treatment, the rotation speed of the ball milling dispersion treatment is 200-300 r/min, the treatment time is 12-24 hours, the ball milling balls are alumina balls, the ball milling medium is absolute ethyl alcohol, and the mass ratio of the ball: powder: 5-7 of absolute ethyl alcohol: 1:1 to 1.4.
8. The synthesis method of claim 7, wherein the mullite powder subjected to the ball milling dispersion treatment is dried and sieved, and then is subjected to heat treatment at 800-1000 ℃ for 2-4 hours to obtain high-purity mullite powder with uniform particle size distribution; preferably, the drying is drying in an oven at 60 ℃ for 12 hours, and the sieving is 200-mesh sieving.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110407414.6A CN115215640A (en) | 2021-04-15 | 2021-04-15 | Method for synthesizing high-purity mullite powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110407414.6A CN115215640A (en) | 2021-04-15 | 2021-04-15 | Method for synthesizing high-purity mullite powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115215640A true CN115215640A (en) | 2022-10-21 |
Family
ID=83604541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110407414.6A Pending CN115215640A (en) | 2021-04-15 | 2021-04-15 | Method for synthesizing high-purity mullite powder |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115215640A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5338707A (en) * | 1991-05-21 | 1994-08-16 | Tomoyuki Inui | Process for production of high-purity mullites |
| CN101700979A (en) * | 2009-10-30 | 2010-05-05 | 陕西科技大学 | Method for preparing nano-mullite powder by sol-gel-ultrasonic chemistry method |
| CN101700980A (en) * | 2009-10-30 | 2010-05-05 | 陕西科技大学 | Method for preparing nano-mullite powder by sol-gel-hydrothermal method |
| CN102503387A (en) * | 2011-09-27 | 2012-06-20 | 中国地质大学（武汉） | Method for preparing high-purity super-fine mullite powder |
| CN104529421A (en) * | 2014-12-08 | 2015-04-22 | 武汉理工大学 | Preparation method of fine grain mullite ceramic |
-
2021
- 2021-04-15 CN CN202110407414.6A patent/CN115215640A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5338707A (en) * | 1991-05-21 | 1994-08-16 | Tomoyuki Inui | Process for production of high-purity mullites |
| CN101700979A (en) * | 2009-10-30 | 2010-05-05 | 陕西科技大学 | Method for preparing nano-mullite powder by sol-gel-ultrasonic chemistry method |
| CN101700980A (en) * | 2009-10-30 | 2010-05-05 | 陕西科技大学 | Method for preparing nano-mullite powder by sol-gel-hydrothermal method |
| CN102503387A (en) * | 2011-09-27 | 2012-06-20 | 中国地质大学（武汉） | Method for preparing high-purity super-fine mullite powder |
| CN104529421A (en) * | 2014-12-08 | 2015-04-22 | 武汉理工大学 | Preparation method of fine grain mullite ceramic |
Non-Patent Citations (2)
| Title |
|---|
| 周兵: "单相胶莫来石化反应机理的研究", 《中国优秀硕士学位论文全文数据库工程科技Ⅰ辑》 * |
| 张建强等: "以体系自催化作用有效制备高分散的纳米AlMCM-41", 《大连工业大学学报》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Rao | Preparation and characterization of fine‐grain yttrium‐based phosphors by sol‐gel process | |
| Pang et al. | A novel approach for preparation of Y2O3: Eu3+ nanoparticles by microemulsion–microwave heating | |
| CN102241516B (en) | Method for preparing Li4SiO4 ceramic powder by water-based sol-gel process | |
| CN101792164A (en) | Method for preparing nano aluminum oxide through vacuum freeze drying technology | |
| CN108511797B (en) | Li7La3Zr2O12Solid electrolyte preparation method | |
| CN110629288B (en) | Method for preparing whisker-shaped gadolinium aluminate powder material by hydrothermal technology | |
| CN113307303B (en) | High-stability all-inorganic perovskite/aluminum phosphate composite nano material and preparation method and application thereof | |
| CN111019648A (en) | Molten salt method preparation method of oxysalt or oxynitride fluorescent powder | |
| CN107880884B (en) | Preparation method of cerium-doped rare earth silicate polycrystalline powder | |
| CN109111230A (en) | A kind of yttrium oxide-bitter earth nano composite granule and preparation method thereof | |
| JP2022542325A (en) | Infrared selective nano-functional composition for radiative cooling and method of making same | |
| CN106430289B (en) | A kind of method of low temperature preparation high-specific area nano gallate spinel | |
| CN104557101A (en) | Preparation method for porous lithium zirconate block | |
| CN115215640A (en) | Method for synthesizing high-purity mullite powder | |
| Li et al. | Effect of process parameters on the synthesis of YAG nano-crystallites in supercritical solvent | |
| CN1272280C (en) | Preparation method of niobium doped barium sodium titanate nano-powder | |
| Pan et al. | Co-precipitation synthesis of lutetium aluminum garnet (LuAG) powders: the influence of ethanol | |
| CN101070175A (en) | Method for preparing nano Al2O3 adopting salt-melting calcination process | |
| CN109368682B (en) | Preparation method of superfine cerium-oxygen-sulfur compound | |
| CN111137922B (en) | Preparation method of tantalum-oxygen nanosheet | |
| CN112340758A (en) | Preparation of high-purity alpha-Al by low-temperature calcination of aluminum ammonium sulfate2O3Method for producing powder | |
| Zhang et al. | Hemispheric ordered porous Eu (TTA) 3 (TPPO) 2/ZnO fluorescence composites and its preparation method | |
| CN111825467B (en) | Method for preparing nano zirconia by using spray granulator | |
| CN114014349B (en) | Preparation method of YAG nano powder | |
| Chen et al. | Ammonium citrate-assisted combustion synthesis and photoluminescence properties of Dy: YAG nanophosphors |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20221021 |