Method for preparing high-pruity alumina powder

A technology of high-purity alumina and alumina, which is applied in the preparation of alumina/hydroxide, alkali metal aluminate/aluminum oxide/aluminum hydroxide, alumina/aluminum hydroxide, etc., which can solve the problems of purity limitation, Serious environmental pollution, low purity and other problems, to achieve the effect of low cost

Active Publication Date: 2005-02-16
GUIZHOU BRANCH CHINA ALUMINUM IND
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Problems solved by technology

Chinese patent documents 95103368.9 and 95105843.6 relate to a process for producing alumina and alumina micropowder by salting-out method, the main disadvantages of which are low purity and serious environmental pollution
Chinese patent document 93110316.9 relates to a high-purity ultra-fine alumina production process and device, and ammonium alum is decomposed to obtain γ-AL 2 o 3 , and then invert to α-AL 2 o 3 , calcination produces corrosive acid gas, which has economic and environmental problems
This process requires a large amount of alcohol inventory and distillation system, the risk of fire and explosion is high during operation, and the cost of the product is high
CN1448340A discloses an improved aluminum ammonium sulfate method, that is, aluminum ammonium carbonate pyrolysis method to prepare high-purity alumina. Although the pollution of acid gas is avoided, the preparation cost is still high, and the purity is also limited by the process conditions.
All of the above-mentioned processes have a problem of high preparation cost, which is generally more than 40,000 yuan / ton

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Embodiment 1

[0020] The preparation method of the high-purity alumina powder of the present invention uses the intermediate product aluminum hydroxide (which can be the middle stage product of seed or carbon aluminum hydroxide) of the alumina production process by the sintering method as a raw material, and prepares aluminum by dissolving Sodium aluminate solution, adding 9% aluminum hydroxide by weight of aluminum hydroxide as impurity remover, used to adsorb harmful impurities in the sodium aluminate solution, stirred for 45 minutes, and separated liquid-solid to prepare high-purity sodium aluminate solution. This solution is used as the decomposition mother solution, the decomposition temperature is controlled at 60°C, and the concentration of alumina in the solution is 100g / l, 7% active aluminum hydroxide is added as the seed crystal for carbonation and decomposition of the seeds to prepare high-purity aluminum hydroxide. The decomposition time Controlled within 5 hours, carbon dioxide ...

Embodiment 2

[0023] The preparation method of the high-purity alumina powder of the present invention uses the intermediate product aluminum hydroxide of the alumina production process by the sintering method as a raw material, prepares a sodium aluminate solution by dissolving, and adds 7% of the weight of aluminum hydroxide Aluminum micropowder was used as impurity remover, and after stirring for 40 minutes, liquid-solid separation was carried out to prepare high-purity sodium aluminate solution. This solution is used as the decomposition mother solution, the decomposition temperature is controlled at 65°C, and the concentration of alumina in the solution is 110g / l, 8% active aluminum hydroxide is added as the seed crystal for carbonation and decomposition of the seeds to prepare high-purity aluminum hydroxide. The decomposition time Controlled in 6 hours, carbon dioxide flow 0.05m 3 / h·l, the decomposition rate of the carbonation decomposition process is controlled at 83%. After the dec...

Embodiment 3

[0026] The preparation method of the high-purity alumina powder of the present invention uses the intermediate product aluminum hydroxide of the alumina production process by the sintering method as a raw material, prepares a sodium aluminate solution by dissolving, and adds 10% of the weight of aluminum hydroxide Aluminum was used as impurity remover, and after stirring for 48 minutes, liquid-solid separation was carried out to prepare high-purity sodium aluminate solution. This solution is used as the decomposition mother solution, the decomposition temperature is controlled at 65°C, and the concentration of aluminum oxide in the solution is 120g / l. Add 9% high-purity aluminum hydroxide as a seed crystal for carbonation and decomposition of the seeds to prepare high-purity aluminum hydroxide. Decomposition The time is controlled at 6 hours, carbon dioxide is introduced, and the decomposition rate of the carbonation decomposition process is controlled at 80%. After the decompo...

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Abstract

The invention discloses a method to produce highly pure Alumina powder. The steps are as follows: deploying Aluminium hydroxide which is produced in the process of manufacturing alumina using sintering process to be solution, disposing of impurity, adding seed crystal to prepare highly pure aluminium hydroxide; removing Na in the solution, getting highly pure bodhmite after hydrothermal synthesis; and after washing and baking, highly pure Alumina can be obtained. The cost is about 15 thousand per ton, which is far less than current market price, 40-60 thousand per ton. It can put into production in a large scale and it is easy to reach 1-5 thousand ton per year. With a low cost, no pollution and high purity (over 99.99 percent), the production is widely used in rare earth fluorescence materials, high voltage Na lamp and other relative special Alumina fine ceramics field.

Description

technical field [0001] The invention relates to a method for preparing high-purity alumina powder, which is an alumina refining technology. Background technique [0002] High-purity alumina is mainly used in rare earth fluorescent materials, high-pressure sodium lamps, gemstones and other abrasives, catalysts, and special alumina ceramics. High-purity alumina powder generally refers to the purity ≥ 99.99%, the particle size is in micron or submicron level, and has different specific requirements according to its different uses. At present, the methods for preparing high-purity alumina powder mainly include: aluminum ammonium sulfate pyrolysis method, aluminum ammonium carbonate pyrolysis method, organic aluminum hydrolysis method, spark discharge method, mercuric oxide spark hydrolysis method and activated aluminum powder hydrolysis method. Chinese patent documents 95103368.9 and 95105843.6 relate to a process for producing alumina and alumina micropowder by salting-out met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/14C01F7/30C01F7/46
Inventor 刘昌俊李文成王立家李明王树栋
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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