A method for rapid preparation of airgel by pressure-swing accelerated solvent extraction

A technology for accelerating solvents and aerogels, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve the problems of low quality of aerogel powder, limited application fields, easy to occur salting out, etc. The effect of processing, simplifying the process and reducing the production risk

Active Publication Date: 2020-04-07
浙江岩谷科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the existence of ions, this method greatly slows down the speed of surface silanization treatment. It is only suitable for the preparation of airgel powder, and the application field is very limited. Due to the incomplete removal of ions, there are still a large amount of residues in the gel powder. Ions, salting-out phenomenon is very easy to occur during storage, resulting in SiO 2 Airgel powder is of low quality and poor performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Sodium silicate and water are mixed at a volume ratio of 1:3 at room temperature, added to 5% sulfuric acid solution, and the pH reaches 5.0, and a gel is formed after 30 seconds. After the gel is crushed, put it into a supercritical extraction kettle, and pump in an acetone aqueous solution with a volume concentration of 10% at 100°C. Keep the liquid level of the acetone aqueous solution in the extraction kettle constant, and control the absolute pressure of the supercritical extraction kettle to periodically change between 0.15MPa and 0.35MPa, first gradually increase the pressure from 0.15MPa to 0.35MPa within 2min, and maintain it for 1min Finally, the pressure is gradually reduced from 0.35MPa to 0.15MPa within 2 minutes, and the pressure is repeatedly raised and lowered at this speed. The volume concentration of acetone in the extraction kettle was gradually increased from 10% to 92% within 20 minutes, the pump was stopped, and after maintaining for 2 minutes, the...

Embodiment 2

[0039] Mix potassium silicate and water at a volume ratio of 1:2 at room temperature, add it to 20% nitric acid solution, make the pH reach 5.5, pour the mixture into a mold with a 10mm thick glass fiber felt, and form after 2 minutes gel. Put the composite material into a supercritical extraction kettle, pump in alcohol with a mass concentration of 20% at 120°C, after the alcohol is immersed in the composite material, pump water and alcohol with a mass concentration of 92% at the same time, and control the ratio of water and alcohol through a flow meter After the two are mixed, the mass concentration of alcohol gradually increases from 50% to 92%, and then enters the supercritical extraction kettle, and the low-concentration alcohol in the reaction kettle is pumped out to maintain the liquid level in the kettle. Control the absolute pressure of the supercritical extraction kettle to periodically change between 0.05MPa and 0.3MPa, first increase the pressure from 0.05MPa to 0....

Embodiment 3

[0041] Mix sodium silicate and water at a volume ratio of 1:4 at room temperature, add it to 15% citric acid solution, make the pH reach 5.0, pour the mixture into a mold with a 6mm thick glass fiber mat, and after 1min Form a gel. Put the composite material into a supercritical extraction kettle, pump in an aqueous methanol solution with a mass concentration of 85% at 90°C, and keep it for 3 minutes after the methanol aqueous solution is immersed in the composite material, and then continue to pump in an aqueous methanol solution with a mass concentration of 85% at 90°C , while pumping out the low-concentration alcohol in the reactor to keep the liquid level in the reactor unchanged. Control the absolute pressure of the supercritical extraction kettle to periodically change between 0.1MPa and 0.35MPa, first increase the pressure rapidly from 0.05MPa to 0.35MPa within 30s, and after maintaining it for 1min, quickly reduce the pressure from 0.35MPa to 0.1MPa within 30s , accor...

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Abstract

The invention discloses a method used for pressure variable accelerated solvent extraction rapid preparation of aerogel. The method comprises following steps: 1, a certain amount of an inorganic silicon source and water are mixed for dilution, a certain amount of an acid is added so as to obtain a salt-containing silicon sol, and a certain period of reaction is carried out so as to obtain a gel; 2, under periodic pressure changing conditions, an organic solvent aqueous solution with a concentration increasing with time is adopted for accelerated solvent extraction of the gel obtained in step 1; and 3, the processed gel obtained in step 2 is subjected to drying. The method is simple in operation process, short in production period, and low in energy consumption; the obtained aerogel is complete in structure, low in heat conduction coefficient, and high in mechanical strength.

Description

technical field [0001] The invention relates to the technical field of manufacturing nanoporous airgel materials, in particular to a method for rapidly preparing airgel through pressure-swing accelerated solvent extraction. Background technique [0002] SiO 2 Airgel is currently one of the most widely concerned thermal insulation materials, which is composed of highly cross-linked SiO 2 The porous material prepared by the gel through a special drying process has a three-dimensional network structure, and its skeleton and pore structure are at the nanometer level. The unique structure makes SiO 2 Airgel material has extremely low thermal conductivity, can effectively inhibit heat conduction and heat convection, and is considered to be the solid material with the best thermal insulation performance. [0003] Due to its huge application potential, researchers all over the world have invested in the development of various SiO2 airgel preparation methods, and the silicon sourc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/158
CPCC01B33/1585
Inventor 闫方闵阳
Owner 浙江岩谷科技有限公司
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