Preparation of nano aluminum oxide without hard coacervation

A technology of nano-alumina and aluminum nitrate, applied in the preparation of nano-alumina and nano-alumina powder, can solve the problem of affecting the reliability and repeatability of ceramic material performance, difficult to effectively control particle size and shape, difficult to Prevent the particles from coarsening and hard agglomerates, and achieve the effects of good pressing and sintering performance, reducing transformation temperature and transformation time, and low energy consumption and cost.

Inactive Publication Date: 2005-02-23
WUHAN UNIV
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  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

At present, the industrial preparation of alumina powder mainly adopts the Bell method and the thermal decomposition of aluminum ammonium alum. This method requires high temperature conditions of 1300-1500 °C, requires special heating equipment, and increases the difficulty of synthesis.
However, traditional wet chemical methods are difficult to effectively control the size and shape of particles, and most importantly, it is usually difficult to prevent the coarsening of particles and the formation of hard aggregates at the high temperature required for alumina transformation
Therefore, it is difficult to prepare real nano-alumina powder by traditional wet chemical method
Once the hard agglomerates are formed, it will affect the pressing and sintering performance of the powder, thus greatly affecting the reliability and repeatability of the performance of the prepared ceramic material, making it a sharp contradiction with the requirements of high technology
In the post-treatment stage of wet chemical methods, supercritical drying and freeze drying technologies can be used to solve the problem of hard agglomeration of nanoparticles, but such methods have problems such as complex equipment and discontinuous production process.
Using aluminum alkoxide as raw material to prepare nano-alumina particles by sol-gel method has good performance but the cost is too high, so it is only suitable for laboratory preparation and use

Method used

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  • Preparation of nano aluminum oxide without hard coacervation
  • Preparation of nano aluminum oxide without hard coacervation
  • Preparation of nano aluminum oxide without hard coacervation

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preparation example Construction

[0021] The preparation process of the present invention is as follows:

[0022]

[0023] 1. Aluminum nitrate, ammonium carbonate and n-butanol are commercially available products. At the same time, in order to control the purity, ammonia and carbon dioxide can be directly purchased to prepare ammonium carbonate and ammonia water.

[0024] 2. Under 1400r / min magnetic stirring, add an equal volume of (A) solution to the above (B) solution at a rate of 40-60 drops / min, after the titration is completed, continue to stir for 1h, age for 36h; centrifuge, Wash 4 times with secondary water and 3 times with absolute ethanol, dry at 80°C for 10 h, remove surface water, and obtain dry powder.

[0025] 3. Add the obtained dry powder into n-butanol until the n-butanol completely immerses the sample, after ultrasonic dispersion, reflux for 2 hours, distill and remove the n-butanol-water azeotrope at 93°C, remove the residue and adsorb And surface bound water, when the distillate tempera...

Embodiment 1

[0028] Embodiment 1: under the magnetic stirring of 1400r / min, the concentration that will contain 8wt%PEG 400 is the Al(NO of 0.2mol / L 3 ) 3 Solution is added the concentration of 0.6mol / L (NH 4 ) 2 CO 3In the solution (pH 9.5), after the titration is completed, continue to stir for 1h, age for 36h; centrifuge, wash 4 times with secondary water, wash 3 times with absolute ethanol, dry at 60-80°C for 10h, remove surface water, and obtain dry powder. Add the obtained dry powder into n-butanol, after ultrasonic dispersion, reflux for 2 hours, distill to remove the n-butanol-water azeotrope at 93°C, stop the distillation when the temperature of the fraction rises to the boiling point of n-butanol at 117°C , After continuing to reflux for 2h, n-butanol was recovered by distillation under reduced pressure to obtain a loose powder. The product obtained by calcination at 750°C, the particle morphology is shown in figure 1 , particle size and shape uniformity, good monodispersit...

Embodiment 2

[0029] Embodiment 2: under the magnetic stirring of 1400r / min will contain the Al(NO of 0.3mol / L with 6wt%PEG 400 concentration 3 ) 3 The solution is added into an equal volume of (NH 4 ) 2 CO 3 In the solution (pH 9.8), after the titration is completed, continue to stir for 1h, age for 36h; centrifuge, wash 4 times with secondary water, wash 3 times with absolute ethanol, dry at 60-80°C for 10h, remove surface water, and obtain dry powder. Add the obtained dry powder into n-butanol, after ultrasonic dispersion, reflux for 2 hours, distill to remove the n-butanol-water azeotrope at 93°C, stop the distillation when the temperature of the fraction rises to the boiling point of n-butanol at 117°C , After continuing to reflux for 2h, n-butanol was recovered by distillation under reduced pressure to obtain a loose powder. The product obtained by calcining at 750°C has better particle size and shape uniformity, good monodispersity, no hard agglomeration phenomenon, the particle...

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Abstract

A process for preparing nano-alumina without hard conglomerations includes such steps as proportionally and respectively dissolving aluminium nitrate and ammonium carbonate in secondary distilled water to obtain their solutions, adding polyethanediol to them to obtain their composite solutions, mixing them together, stirring, centrifugal dewatering, drying, azeotropic distilling, and high-temp calcining.

Description

technical field [0001] The present invention relates to the preparation of nano-alumina, which belongs to the field of fine chemical industry, and more specifically relates to a method for preparing nano-alumina without hard agglomeration. This method can be used to prepare basic non-alumina with an average particle diameter locally controllable in the range of 10-70nm. Hard agglomerated nano-alumina powder. Background technique [0002] Nano-alumina (Al 2 o 3 ) refers to alumina products with a particle size of less than 100 nanometers. Because of its small particle size and large specific surface area, it has high chemical activity and is widely used in artificial gemstones, reagents, catalysts and carriers, luminescent materials, electronic ceramic substrates, and the aerospace field. Nano-alumina is several times stronger than ordinary alumina in toughening and strengthening ceramics and rubber. Especially to improve the density, smoothne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/30
Inventor 彭天右
Owner WUHAN UNIV
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