CN110963516A - Preparation method of spherical α -alumina powder - Google Patents
Preparation method of spherical α -alumina powder Download PDFInfo
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- CN110963516A CN110963516A CN201911348808.8A CN201911348808A CN110963516A CN 110963516 A CN110963516 A CN 110963516A CN 201911348808 A CN201911348808 A CN 201911348808A CN 110963516 A CN110963516 A CN 110963516A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/30—Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
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- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/44—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water
- C01F7/441—Dehydration of aluminium oxide or hydroxide, i.e. all conversions of one form into another involving a loss of water by calcination
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
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- C01P2006/80—Compositional purity
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Abstract
A preparation method of spherical α -alumina powder belongs to the technical field of inorganic non-metallic materials and comprises the following steps of S1, hydrolyzing organic aluminum salt after rectification and purification under the condition that the pH value is less than 8 to obtain aluminum sol, evaporating and removing organic solvent in the aluminum sol under the condition of vacuum heating, S2, mixing the aluminum sol into non-polar organic solvent, stirring at high speed to form emulsion, adding a certain amount of stabilizing agent into the emulsion to form spheroidized aluminum hydroxide sol particles, centrifugally separating the spheroidized aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder, S3, conveying the dried powder prepared in the step S2 into a vertical high-temperature furnace, enabling the dried powder to pass through a high-temperature region of 1100 ℃ and 1300 ℃ for 60-180min to obtain spherical α -alumina powder, wherein the conversion rate of a phase α can be improved, and the prepared alumina powder has controllable particle size and is free of agglomeration and breakage.
Description
Technical Field
The invention relates to a technology in the field of inorganic non-metallic materials, in particular to a preparation method of spherical α -alumina powder.
Background
As the most common heat conducting/dissipating fillers of numerous materials such as heat conducting silica gel, heat conducting plastic and the like, spherical alumina powder is a key raw material in the field of heat conducting and dissipating due to low price, stable performance and abundant raw materials, as the heat conducting alumina powder, generally, several key technical requirements need to be paid attention to that α phase is high, the larger the crystal size is, the lower the porosity is, the higher the heat conductivity is, the higher the sphericity is, the higher the fluidity is, the larger the filling amount is, the heat conductivity of the final product is also increased.
The most main production process of the existing spherical alumina powder is a flame method, namely classified common flake or angular α alumina powder or aluminum hydroxide powder is conveyed into a high-temperature flame furnace with the temperature of more than 2000 ℃, the alumina powder is instantly melted in flame, the melted alumina is spheroidized due to surface tension and then is rapidly cooled and collected to form the spherical alumina powder.
The preparation method of spherical alumina is characterized by that it includes the steps of placing aluminium powder into a furnace full of oxygen, making instantaneous oxidation reaction, cooling and collecting, and the combustion oxidation reaction of aluminium powder can be accompanied by a large quantity of heat release, and can instantaneously reach a high temperature of above 2000 deg.C, and said method is characterized by that it can produce alumina powder whose grain size is finer than that of the above-mentioned flame method, however, the produced alumina powder is generally theta-alumina, and its specific gravity is lower and thermal conductivity is also low, and the theta-alumina powder can be heat-treated at high temperature, so that the conversion rate of α -alumina can be further raised, but in the conversion process, the powder bodies can be seriously adhered together, and can result in loss of fluidity so as to seriously affect the use of said powder as heat-conducting glue or filler in plastics.
However, the sphericity of the spherical alumina powder prepared by the method is not high, incomplete spheres such as apple shapes, socket shapes or pear shapes are often generated, and the defects can not be eliminated by normal high-temperature treatment, so that the flowability and the thermal conductivity of the subsequent thermal conductive filler are seriously influenced.
The present invention has been made to solve the above-mentioned problems occurring in the prior art.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a preparation method of spherical α -alumina powder, which can improve the α phase conversion rate, and the prepared alumina powder has controllable particle size and is free from agglomeration and crushing.
The invention comprises the following steps:
s1, hydrolyzing the rectified and purified organic aluminum salt under the condition that the pH value is less than 7 to obtain aluminum sol; evaporating to remove the organic solvent in the aluminum sol under the vacuum heating condition;
s2, mixing the aluminum sol into a nonpolar organic solvent, stirring at a high speed to form an emulsion, adding a certain amount of a stabilizer into the emulsion to form spheroidized aluminum hydroxide sol particles, centrifugally separating the spheroidized aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s3, inputting the dried powder obtained in the step S2 into a vertical high-temperature furnace, and enabling the dried powder to pass through a high-temperature region of 1100-1300 ℃ for 60-180min to obtain the spherical α -alumina powder.
Preferably, the organic aluminum salt is at least one of aluminum isopropoxide and aluminum butoxide.
Preferably, the non-polar organic solvent is at least one of cyclohexane, heptane, benzene, toluene.
Preferably, the stabilizer is at least one of span 20-80, Tween 20-80, AOT, Triton X-100 and hexadecyl trimethyl ammonium bromide.
Technical effects
Compared with the prior art, the invention has the following technical effects:
1) the prepared spherical α -alumina powder has controllable particle size, no agglomeration and no breakage, the conversion rate of α phase is more than 95%, and the purity is more than 99.999%, so that the good thermal conductivity of the thermal conductive product is ensured;
2) the organic solvent in the step S1 and the step S2 can be recycled, so that the energy is saved and the environment is protected.
Drawings
FIG. 1 is an SEM photograph of spherical alumina prepared in example 1;
FIG. 2 is a graph showing a distribution of the particle size of spherical alumina obtained in example 1.
Detailed Description
The invention is described in detail below with reference to the drawings and the detailed description.
Example 1
S1, adding 2040g of aluminum isopropoxide into 2040g of deionized water, adjusting the pH of the mixed solution to 4 with nitric acid, pouring the mixed solution into a flask, stirring, heating in a water bath, controlling the temperature to be 80 ℃ for reaction for 2 hours, and vacuumizing to remove isopropanol to obtain aluminum hydroxide aluminum sol;
s2, pouring the obtained aluminum sol into 2040g of cyclohexane, stirring at a high speed of 500rpm, adding 40g of span 80, then continuing stirring for 30min, and then adding 204g of ammonia water with the concentration of 14% to obtain spheroidized aluminum hydroxide sol particles; centrifugally separating the aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s4, inputting the dried powder into a vertical high-temperature furnace, and keeping the temperature at 1200 ℃ for 180min to obtain the high-purity spherical α -alumina powder.
As shown in fig. 1 and fig. 2, the particle size D50 of the prepared spherical α -alumina powder is 500nm, the distribution is uniform, the powder is free from agglomeration and breakage, the conversion rate of α phase is more than 95%, and the purity is more than 99.999%.
Example 2
S1, adding 2040g of aluminum isopropoxide into 2040g of deionized water, adjusting the pH of the mixed solution to 4 with nitric acid, pouring the mixed solution into a flask, stirring, heating in a water bath, controlling the temperature to be 80 ℃ for reaction for 2 hours, and vacuumizing to remove isopropanol to obtain aluminum hydroxide aluminum sol;
s2, pouring 2040g of cyclohexane into the obtained aluminum sol, stirring at a high speed of 200rpm, adding 40g of Tween, continuing stirring for 30min, and adding 204g of ammonia water with the concentration of 14% to obtain spheroidized aluminum hydroxide sol particles; centrifugally separating the aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s4, inputting the dried powder into a vertical high-temperature furnace, and keeping the temperature at 1300 ℃ for 120min to obtain the high-purity spherical α -alumina powder.
The prepared spherical α -alumina powder has the grain diameter D50 of 2.5 mu m, is uniformly distributed, and has no agglomeration and no crushing, the conversion rate of α phase is more than 95 percent, and the purity is more than 99.999 percent.
Example 3
S1, adding 2040g of aluminum isopropoxide into 2040g of deionized water, adjusting the pH of the mixed solution to 4 with nitric acid, pouring the mixed solution into a flask, stirring, heating in a water bath, controlling the temperature to be 80 ℃ for reaction for 2 hours, and vacuumizing to remove isopropanol to obtain aluminum hydroxide aluminum sol;
s2, pouring the obtained aluminum sol into 2040g of cyclohexane, stirring at a high speed of 150rpm, adding 40g of span 80, then continuing stirring for 30min, and then adding 204g of ammonia water with the concentration of 14% to obtain spheroidized aluminum hydroxide sol particles; centrifugally separating the aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s4, inputting the dried powder into a vertical high-temperature furnace, and keeping the temperature at 1300 ℃ for 60min to obtain the high-purity spherical α -alumina powder.
The prepared spherical α -alumina powder has the particle diameter D50 of 5 mu m, is uniformly distributed, and has no agglomeration and no breakage, the conversion rate of α phase is more than 95 percent, and the purity is more than 99.999 percent.
Example 4
S1, adding 2040g of aluminum isopropoxide into 2040g of deionized water, adjusting the pH of the mixed solution to 4 with nitric acid, pouring the mixed solution into a flask, stirring, heating in a water bath, controlling the temperature to be 80 ℃ for reaction for 2 hours, and vacuumizing to remove isopropanol to obtain aluminum hydroxide aluminum sol;
s2, pouring the obtained aluminum sol into 2040g of cyclohexane, stirring at a high speed of 100rpm, adding 40g of Tween, continuing stirring for 30min, and adding 204g of ammonia water with the concentration of 14% to obtain spheroidized aluminum hydroxide sol particles; centrifugally separating the aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s4, inputting the dried powder into a vertical high-temperature furnace, and keeping the temperature at 1300 ℃ for 60min to obtain the high-purity spherical α -alumina powder.
The prepared spherical α -alumina powder has the grain diameter D50 of 52 mu m, is uniformly distributed, and has no agglomeration and no breakage, the conversion rate of α phase is more than 95 percent, and the purity is more than 99.999 percent.
It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (4)
1. The preparation method of the spherical α -alumina powder is characterized by comprising the following steps:
s1, hydrolyzing the rectified and purified organic aluminum salt under the condition that the pH value is less than 8 to obtain aluminum sol; evaporating to remove the organic solvent in the aluminum sol under the vacuum heating condition;
s2, mixing the aluminum sol into a nonpolar organic solvent, stirring at a high speed to form an emulsion, adding a certain amount of a stabilizer into the emulsion to form spheroidized aluminum hydroxide sol particles, centrifugally separating the spheroidized aluminum hydroxide sol particles, and drying in vacuum to obtain spherical aluminum hydroxide sol powder;
s3, inputting the dried powder obtained in the step S2 into a vertical high-temperature furnace, and enabling the dried powder to pass through a high-temperature region of 1100-1300 ℃ for 60-180min to obtain the spherical α -alumina powder.
2. The method for preparing spherical α -alumina powder according to claim 1, wherein the organic aluminum salt is at least one of aluminum isopropoxide and aluminum butoxide.
3. The method for preparing spherical α -alumina powder according to claim 1, wherein the nonpolar organic solvent is at least one of cyclohexane, heptane, benzene, and toluene.
4. The method for preparing spherical α -alumina powder according to claim 1, wherein the stabilizer is at least one of span 20-80, tween 20-80, AOT, triton X-100, and cetyl trimethyl ammonium bromide.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111807393A (en) * | 2020-07-17 | 2020-10-23 | 青岛科技大学 | Method for improving compatibility of aluminum hydroxide |
| CN112457057A (en) * | 2020-12-30 | 2021-03-09 | 湖南威斯康新材料科技有限公司 | Composite burning bearing plate for electronic ceramic and preparation method thereof |
| CN112591777A (en) * | 2020-12-23 | 2021-04-02 | 苏州柔陶新材料有限公司 | Preparation method of high-purity spherical gamma-alumina powder |
| CN113184886A (en) * | 2021-04-14 | 2021-07-30 | 雅安百图高新材料股份有限公司 | Preparation method and product of high-thermal-conductivity spherical alumina |
| CN115340113A (en) * | 2022-09-19 | 2022-11-15 | 合肥中航纳米技术发展有限公司 | Preparation method of vapor phase method nano alumina |
| CN116042098A (en) * | 2023-02-08 | 2023-05-02 | 广东粤港澳大湾区黄埔材料研究院 | Nano alumina polishing solution and application thereof in polishing of infrared chalcogenide glass |
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| CN104163444A (en) * | 2014-07-18 | 2014-11-26 | 西南科技大学 | Alpha-alumina hollow ball preparation method |
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- 2019-12-24 CN CN201911348808.8A patent/CN110963516A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104163444A (en) * | 2014-07-18 | 2014-11-26 | 西南科技大学 | Alpha-alumina hollow ball preparation method |
Non-Patent Citations (1)
| Title |
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| M. CHATTERJEE等: "M. Chatterjee等", 《JOURNAL OF MATERIALS RESEARCH》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111807393A (en) * | 2020-07-17 | 2020-10-23 | 青岛科技大学 | Method for improving compatibility of aluminum hydroxide |
| CN112591777A (en) * | 2020-12-23 | 2021-04-02 | 苏州柔陶新材料有限公司 | Preparation method of high-purity spherical gamma-alumina powder |
| CN112457057A (en) * | 2020-12-30 | 2021-03-09 | 湖南威斯康新材料科技有限公司 | Composite burning bearing plate for electronic ceramic and preparation method thereof |
| CN113184886A (en) * | 2021-04-14 | 2021-07-30 | 雅安百图高新材料股份有限公司 | Preparation method and product of high-thermal-conductivity spherical alumina |
| CN115340113A (en) * | 2022-09-19 | 2022-11-15 | 合肥中航纳米技术发展有限公司 | Preparation method of vapor phase method nano alumina |
| CN115340113B (en) * | 2022-09-19 | 2023-11-14 | 合肥中航纳米技术发展有限公司 | Preparation method of gas-phase nanometer alumina |
| CN116042098A (en) * | 2023-02-08 | 2023-05-02 | 广东粤港澳大湾区黄埔材料研究院 | Nano alumina polishing solution and application thereof in polishing of infrared chalcogenide glass |
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