Preparation method of high-purity aluminum oxide for sapphire

A high-purity alumina and sapphire technology, applied in the preparation of alumina/hydroxide, purification of aluminate/alumina/aluminum hydroxide, etc., can solve problems such as inability to use optoelectronic devices

Pending Publication Date: 2021-08-24
山东惠远科技发展有限公司
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Problems solved by technology

However, during the hydrolysis process of aluminum alkoxide, alkoxy groups will remain due to insufficient hydrolysis. Although the alkoxy groups remaining in the high-temperature oxidation atmosphere will decompose and gasify, some alkoxy groups wrapped inside the precursor particles will not fully contact Oxygen and carbonization, which causes the sapphire produced by the aluminum alcohol method of high-purity alumina to sometimes appear light yellow or even brown, and cannot be used for optoelectronic devices

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  • Preparation method of high-purity aluminum oxide for sapphire

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preparation example Construction

[0022] The invention provides a method for preparing high-purity alumina for sapphire, comprising the following steps:

[0023] Under stirring conditions, aluminum alkoxide and water are mixed to carry out hydrolysis reaction to obtain pseudo-boehmite-alcohol-water slurry;

[0024] remove the alcohol in the pseudo-boehmite-alcohol-water slurry, then mix the resulting material with a carbon remover and water to obtain a mixed material; the carbon remover is aqueous hydrogen peroxide, chlorine dioxide, chlorine ammonium perchlorate, persulfuric acid, ammonium persulfate, nitric acid, ammonium nitrate, aluminum nitrate nonahydrate, concentrated sulfuric acid, ammonium sulfate, aluminum sulfate octadecahydrate, concentrated hydrochloric acid, ammonium chloride, aluminum chloride hexahydrate, One or more of ammonium fluoride, aluminum fluoride, ammonium iodate and ammonium bromide;

[0025] The mixed material is dried and calcined in sequence to obtain high-purity alumina for sapp...

Embodiment 1

[0046] 2kg of liquid aluminum isopropoxide (purity not less than 99%, the total content of metal element impurities such as Na, Fe, Si, K, Ca, Cu, Ti and Zn is less than 0.005wt.%) is introduced into 4L with reflux equipment In the reaction kettle, under the condition of stirring at 80°C (120r / min), add 550g of high-purity water into the reaction kettle, and continue stirring for 4 hours after adding water to hydrolyze aluminum isopropoxide into pseudoboehmite-isopropanol -Water slurry; the slurry is vacuum-dried, the drying temperature is 90°C, and the drying time is 6h; the pseudo-boehmite (AlOOH content is 88.2wt.%) and 10g of aluminum chloride hexahydrate obtained by drying are successively added to the In 700g of high-purity water, mix the above three evenly; the resulting mixture is dried in a blast drying oven at 105°C for 8 hours; the resulting dried product is crushed into a powder with a particle size of less than 150 microns, and then the powder is placed in a ventil...

Embodiment 2

[0050] 2000kg of liquid aluminum isopropoxide (purity not less than 99%, total content of Na, Fe, Si, K, Ca, Cu, Ti, Zn less than 0.005wt.%) is introduced into a 4000L reactor and stirred at 80°C Under the condition (rotating speed is 40r / min), 550kg high-purity water is added in the reactor, after adding water, continue to stir for 4h to hydrolyze aluminum isopropoxide into pseudo-boehmite-isopropanol-water slurry; Process in a circulating flash dryer, the protective gas is nitrogen, the inlet temperature is 250°C, and the discharge temperature is 80°C; the dried pseudo-boehmite (AlOOH content is 84wt.%) and 10kg aluminum chloride hexahydrate are successively Add it into 2000kg of high-purity water, and use a mixer to mix the above three evenly; the resulting mixture is spray-dried with an inlet temperature of 350°C and an outlet temperature of 100°C; the spray-dried powder is placed in a ventilated corundum crucible with a cover, The filling rate is 70%, the filling height i...

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Abstract

The invention provides a preparation method of high-purity aluminum oxide for sapphire, and belongs to the technical field of preparation of inorganic functional materials. According to the method, residual organic carbon is oxidized into carbon dioxide at high temperature by using the carbon removal agent and utilizing the strong oxidation effect or auxiliary oxidation effect of the carbon removal agent, so that the residual carbon content in aluminum oxide prepared by the aluminum alcoholization method is reduced, and the problem that sapphire prepared from high-purity aluminum oxide prepared by the aluminum alcoholization method is faint yellow and even brown and cannot be used as a photoelectric device is solved. The result of the embodiment shows that the residual carbon content of the prepared aluminum oxide is less than 0.001 wt.%, the purity is higher than 99.99%, and when the high-purity aluminum oxide prepared by the method is used for producing sapphire, mixed colors are avoided, and the requirement for growing sapphire single crystals is met.

Description

technical field [0001] The invention relates to the technical field of preparation of inorganic functional materials, in particular to a preparation method of high-purity alumina for sapphire. Background technique [0002] Sapphire (alumina single crystal) has the characteristics of chemical corrosion resistance, heat resistance, good thermal conductivity, high hardness, and high light transmittance. It has become a window material for infrared military devices, satellite space technology, and high-intensity lasers. It is also a semiconductor light-emitting diode ( LED), large-scale integrated circuits and superconducting nanostructure thin films are the most ideal substrate materials. [0003] The main raw material for growing sapphire single crystal is high-purity alumina. The production methods of high-purity alumina include aluminum alcohol method, metal aluminum hydration method, aluminum ammonium sulfate pyrolysis method and improved Bayer method. Among them, the alum...

Claims

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Application Information

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IPC IPC(8): C01F7/46C01F7/30
CPCC01F7/30C01F7/46C01P2004/01C01P2006/80
Inventor 徐前进刘坤吉何香春
Owner 山东惠远科技发展有限公司
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