Method for producing high-purity alpha-aluminum oxide

A technology of alumina and aluminum hydroxide, applied in the direction of alumina/hydroxide, etc., can solve the problems of high product impurity content, high energy consumption, serious environmental pollution, etc., and achieve low production cost, low energy consumption, and technological process short effect

Active Publication Date: 2012-06-20
KUNMING METALLURGY INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above several production methods more or less have the disadvantages of high pro

Method used

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  • Method for producing high-purity alpha-aluminum oxide
  • Method for producing high-purity alpha-aluminum oxide

Examples

Experimental program
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Effect test

Embodiment 1

[0016] Use industrial aluminum hydroxide with a purity of 98.5~99% as raw material. React the raw material with 15-25% hydrochloric acid solution in the reaction tank for 3 hours according to the liquid-solid ratio of 5:1 to obtain aluminum trichloride solution. After the aluminum trichloride solution is filtered, the filtrate is evaporated and crystallized at 80~90°C for 3~4 hours to obtain aluminum trichloride hexahydrate crystals. 3 Under the protection of hydrogen chloride gas per hour, dehydrate at 120~150℃ to obtain anhydrous aluminum trichloride powder, which is placed in a vacuum furnace to maintain a vacuum of 1~10Pa and control the sublimation temperature to 165 ℃ until the vacuum degree drops significantly to obtain aluminum trichloride with a purity exceeding 99.999%. The high-purity aluminum trichloride obtained by sublimation is dissolved in ammonia water for reaction, and the reaction temperature is kept at 20~30°C. After filtering, it is dried until the moistu...

Embodiment 2

[0019] Use industrial sodium metaaluminate with a purity of 90-95% as raw material. React the raw material with 20-30% hydrochloric acid solution in the reaction tank for 10 hours according to the liquid-solid ratio of 8:1 to obtain aluminum trichloride solution. After the aluminum trichloride solution is filtered, the filtrate is evaporated and crystallized at 90~100°C for 5~6 hours to obtain aluminum trichloride hexahydrate crystals. 3 Under the protection of hydrogen chloride gas per hour, dehydrate at a high temperature at 150~200°C to obtain anhydrous aluminum trichloride powder. The anhydrous aluminum trichloride powder is placed in a vacuum furnace to maintain a vacuum degree of 10~10 2 Pa, control the sublimation temperature at 175°C until the vacuum degree drops significantly to obtain aluminum trichloride with a purity exceeding 99.999%. The high-purity aluminum trichloride obtained by sublimation is dissolved in ammonia water for reaction, and the reaction temperat...

Embodiment 3

[0022] Use industrial aluminum hydroxide with a purity of 85-90% as raw material. React the raw material with 10-20% hydrochloric acid solution in the reaction tank for 2 hours according to the liquid-solid ratio of 8:1 to obtain aluminum trichloride solution. After the aluminum trichloride solution is filtered, the filtrate is evaporated and crystallized at 110~130°C for 6~8 hours to obtain aluminum trichloride hexahydrate crystals. 3 Under the protection of hydrogen chloride gas per hour, dehydrate at a high temperature of 200~250°C to obtain anhydrous aluminum trichloride powder. The anhydrous aluminum trichloride powder is placed in a vacuum furnace, and the vacuum degree is kept at 0.1~1Pa, and the sublimation temperature is controlled at 168 ℃ until the vacuum degree drops significantly to obtain aluminum trichloride with a purity exceeding 99.999%. The high-purity aluminum trichloride obtained by sublimation is dissolved in ammonia water for reaction, and the reaction ...

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Abstract

The invention relates to a method for producing high-purity alpha-aluminum oxide, in particular to a method for producing high-purity alpha-aluminum oxide with the purity of more than 99.999 percent by taking industrial aluminum hydroxide or sodium metaaluminate as a raw material. The method comprises the following steps: performing reaction of the industrial aluminum hydroxide or sodium metaaluminate and hydrochloric acid in a sealed reaction tank to obtain an aluminum trichloride solution; filtering, evaporating and crystallizing the aluminum trichloride solution to obtain an aluminum chloride hexahydrate crystal; dehydrating the aluminum chloride hexahydratecrystal in a protection of hydrogen chloride gas at high temperature to obtain anhydrous aluminum trichloride powder; sublimating and purifying the aluminum trichloride powder in a vacuum furnace to obtain aluminum trichloride with the purity of more than 99.999 percent; dissolving the high-purity aluminum trichloride in an ammonia solution, concentrating, crystallizing, filtering and drying to obtain high-purity aluminum hydroxide crystal; and calcining the aluminum hydroxide crystal at high temperature to obtain the high-purity alpha-aluminum oxide powder.

Description

technical field [0001] The invention relates to a method for producing high-purity α-alumina, in particular to a method for producing high-purity α-alumina with a purity greater than 99.999% from industrial aluminum hydroxide or industrial sodium metaaluminate. Background technique [0002] High-purity alumina is alumina with a purity of more than 99.99%. It is mainly used in phosphors, high-purity ceramics, circuit substrates, and artificial substrates. It is widely used in metallurgy, machinery, chemicals, electronics, aviation, and national defense. [0003] Due to the wide application prospects of high-purity alumina powder, the preparation of high-purity alumina powder has been taken as one of the main directions in the field of new materials in recent years. There are many methods for producing high-purity alumina, mainly including choline aluminum hydrolysis. , aluminum ammonium sulfate pyrolysis method, ammonium carbonate pyrolysis method, the methods in the pilot te...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 谢刚杨大锦李怀仁于站良徐亚飞李永刚陈家辉
Owner KUNMING METALLURGY INST
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