Method for preparing monodisperse crystal silicon dioxide spherical particles by coating carbon

A technology of silicon dioxide and spherical particles, applied in the direction of silicon dioxide, silicon oxide, etc., can solve the problem of not solving the production problem of monodisperse spherical crystalline silicon dioxide

Active Publication Date: 2013-05-15
CHANGZHOU YINGZHONG NANO TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The production of monodisperse, non-agglomerated,...

Method used

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  • Method for preparing monodisperse crystal silicon dioxide spherical particles by coating carbon
  • Method for preparing monodisperse crystal silicon dioxide spherical particles by coating carbon
  • Method for preparing monodisperse crystal silicon dioxide spherical particles by coating carbon

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Experimental program
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Effect test

Embodiment 1

[0016] will pass The method is to mix 1g of 8nm silica colloid prepared from analytically pure tetraethoxysilane with 20mg of lithium chloride, 25ml of ethanol, and 5ml of hexane solution. Then, the mixture was atomized and sprayed into an aerosol reactor at 1100° C. with nitrogen gas, cooled, and black carbon-deposited core-shell silica particles with a particle size of 15 nm were collected. Treated at 850 °C for 4 hours under an argon atmosphere, the transmission electron microscope image shows that the silicon dioxide has been completely crystallized ( figure 1 ). XRD detection ( figure 2 ) found that there was no amorphous silica peak. The crystallized sample was treated with oxygen at 350° C. and 1 atmosphere for 10 hours to obtain ~7 nm non-agglomerated, monodisperse α-cristobalite nanoparticles.

Embodiment 2

[0018] pass 5g The method is to mix 150nm silicon dioxide prepared from analytically pure tetraethoxysilane with 100mg of lithium chloride, 10g of glucose, and 200ml of water. Pour this mixture into a polytetrafluoroethylene hydrothermal reaction kettle, stir it magnetically, raise the temperature to 180°C at 5°C / min, and keep the temperature constant for 8 hours. After cooling, it was settled by centrifugation, washed twice with water, dried at 150°C, and collected. Obtain the core-shell structure silica particle ( image 3 ). Treated at 900° C. for 8 hours under an argon atmosphere, transmission electron microscope images and XRD detection show that the silicon dioxide has been completely crystallized, and there is no amorphous silicon dioxide peak. The crystallized sample was treated with oxygen at 350° C. and 1 atmosphere for 10 hours to obtain non-agglomerated, monodisperse α-cristobalite particles of about 130 nm.

Embodiment 3

[0020] Pass 1g through The method is to mix 8nm silica colloid prepared from analytically pure tetraethoxysilane with 25ml ethanol and 5ml hexane solution evenly. Then, the mixture was sprayed into a 1100° C. aerosol reactor with nitrogen atomization, cooled, and collected to obtain black carbon-deposited core-shell structure silica particles with a diameter of 15 nm. Treat at 1000° C. for 12 hours under an argon atmosphere. XRD detection found that the silicon dioxide was not completely crystallized, and there were still amorphous silicon dioxide peaks.

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Abstract

The invention relates to a method for preparing monodisperse crystal silicon dioxide spherical particles by coating carbon, which mainly solves the problems of particle agglomeration, nonuniform size, irregular shape and high cost in the existing silicon dioxide crystal particle preparation process. The method comprises the following steps: (1) coating a carbon layer with uniform thickness on the monodisperse amorphous silicon dioxide spherical particle surface by an aerosol method or hydrothermal method to obtain core-shell structure silicon dioxide/carbon particles; (2) carrying out high-temperature treatment on the core-shell structure particles to crystallize amorphous silicon dioxide into quartz or cristobalite; and (3) removing the carbon layer by oxidation at low temperature to obtain the monodisperse spherical silicon dioxide crystal particles. The technical scheme provided by the invention solves the problems. The spherical monodisperse nano/sub-micro/micro silicon dioxide crystal particles can be used in catalysis, membrane separation, very large-scale integrated circuit packaging material and semiconductor industry, precision valves, hard disks, surface polishing treatment of magnetic heads and the like.

Description

technical field [0001] The invention relates to a method for preparing monodisperse crystal silicon dioxide spherical particles by carbon coating. Background technique [0002] As a catalyst carrier, silica gel has been widely used in the production of important petrochemical products such as acrylonitrile, vinyl acetate, and maleic anhydride. The catalytic reactions that silica gel is used as a carrier mainly include oxidation reaction, hydrogenation reaction, dehydrogenation reaction, hydroformylation reaction, reduction, polymerization, alkylation, desulfurization, etc. However, amorphous silica as a catalyst carrier has disadvantages such as low mechanical strength, easy mud agglomeration, difficult regeneration, easy loss of active components, and difficulty in unloading spent catalysts. There is an urgent need to develop a low-cost, low-pollution preparation method to produce hydrothermally stable and mechanically strong crystalline silica supports. [0003] Quartz h...

Claims

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Application Information

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IPC IPC(8): C01B33/18
Inventor 姜兴茂姜兴盛
Owner CHANGZHOU YINGZHONG NANO TECH
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