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Preparation method of silica

A silicon dioxide and carbon dioxide technology, applied in the production of silicon dioxide, silicon oxide, bulk chemicals, etc., can solve the problems of complicated process, time-consuming, high temperature, etc.

Active Publication Date: 2011-04-20
XIAMEN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former first replaces the organic solvent (mainly alcohol) gel with liquid carbon dioxide, then raises the carbon dioxide to a supercritical state, and finally heats and lowers the pressure to obtain silica aerogel (the process is complicated and time-consuming); the latter Directly increase the temperature and pressure of the organic solvent gel to a supercritical fluid state, keep warm and reduce the pressure to obtain silica airgel (the process requires high temperature and is not safe)

Method used

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Examples

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Effect test

Embodiment 1

[0030] Example 1: Supercritical carbonization reaction coupled with supercritical drying to prepare high pore volume silica products

[0031] Sodium silicate nonahydrate (Sinopharm Chemical Reagent Co., Ltd., analytical pure), carbon dioxide (Xiamen Tongan Air Separation Special Gas Plant, purity 98%).

[0032] First, load a sodium silicate aqueous solution with a concentration of 1 mol / L in the carbonization reactor, set the stirring speed to 800 rpm, and adjust the water bath temperature control system to the experimental temperature. Then start the supercritical fluid supply system, the supercritical fluid enters the preheater, reaches a certain temperature and pressure (reaction temperature 35℃, reaction pressure 9MPa), through the third valve let high-pressure carbon dioxide into the carbonization reactor for reaction, reaction time 30min . At the end of the reaction, close the third valve, press out the material, wash the material with deionized water 3 times until the by-pr...

Embodiment 2

[0037] Example 2: Supercritical carbonization reaction coupled with supercritical drying to prepare highly dispersed silica products

[0038] Sodium silicate nonahydrate (Sinopharm Chemical Reagent Co., Ltd., analytical grade), carbon dioxide (Xiamen Tongan Air Separation Special Gas Plant, purity 98%), ethanol (Sinopharm Group Chemical Reagent Co., Ltd., analytical grade)

[0039] First, load a sodium silicate aqueous solution with a concentration of 1mol / L in the carbonization reactor, add ethanol as an additive (the volume ratio of sodium silicate aqueous solution to ethanol is 4:1), set the stirring speed (800rpm), and adjust the water bath temperature control system to the experiment temperature. Then start the supercritical fluid supply system, the supercritical fluid enters the preheater, reaches a certain temperature and pressure (reaction temperature 35℃, reaction pressure 9MPa), through the third valve let high-pressure carbon dioxide into the carbonization reactor for re...

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Abstract

The invention provides a preparation method of silica, relating to a preparation method of silica materials. In the preparation method, sodium silicate aqueous solution is pumped into a carbonization agitated reactor, supercritical carbon dioxide or subcritical carbon dioxide is added into the carbonization agitated reactor for reaction, so that a reaction product silicide is obtained; after washing and filtering, filtrate enters an evaporator, and carbonate is recycled; a filter cake is pulped by solvent and then forms supercritical fluid which enters a supercritical drying kettle; and after drying, the solvent and the supercritical fluid are separated under reduced pressure in a separation tank, the pressure of the supercritical drying kettle is released, and the product of silica is obtained.

Description

Technical field [0001] The invention relates to a method for preparing silica materials, in particular to a method for preparing silica using super / subcritical fluid to participate in carbonization reaction (supercritical carbonization reaction) coupled with supercritical fluid drying (supercritical drying). Background technique [0002] Silica powder is an amorphous white powder. It is a non-toxic, odorless, and non-polluting non-metallic material. Its microstructure is flocculent and net-like quasi-particle structure. This special structure makes it have unique properties, such as: special optical and electrical properties, high magnetoresistance, nonlinear resistance, and high strength, high toughness, and good stability at high temperatures. It is widely used in catalyst carriers, decolorizers, matting agents, thermal insulation materials, rubber reinforcing agents, plastic fillers, ink thickeners, soft metal polishing agents, insulating and thermal insulation fillers, filler...

Claims

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Application Information

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IPC IPC(8): C01B33/12
CPCY02P20/54
Inventor 李军胡晓慧吕文生庄艺伟洪燕珍苏玉忠王宏涛汤培平汤道英谭玉泉
Owner XIAMEN UNIV
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