CN107128933B - Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material - Google Patents
Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material Download PDFInfo
- Publication number
- CN107128933B CN107128933B CN201710454634.8A CN201710454634A CN107128933B CN 107128933 B CN107128933 B CN 107128933B CN 201710454634 A CN201710454634 A CN 201710454634A CN 107128933 B CN107128933 B CN 107128933B
- Authority
- CN
- China
- Prior art keywords
- water glass
- solution
- water
- silica sol
- thermal insulation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
- C01B33/157—After-treatment of gels
- C01B33/158—Purification; Drying; Dehydrating
- C01B33/1585—Dehydration into aerogels
Landscapes
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Silicon Compounds (AREA)
Abstract
The invention relates to a supercritical drying preparation method of a silicon dioxide aerogel thermal insulation material, which comprises the following steps: the method comprises the following steps: 1) firstly, diluting a water glass solution by using a certain amount of deionized water; 2) slowly adding the diluted water glass solution into the concentrated hydrochloric acid solution, continuously stirring and mixingUniformly mixing to obtain strong acid silica sol; 3) the acidic silica sol solution is rotated to evaporate partial water, taken out, added with water-soluble polar solvent with low surface tension, stirred to be uniformly mixed, and added with water glass solution to adjust the pH value of the solution, thus forming gel; 4) adding water soluble polar solvent into the gel for aging, placing the wet gel in an extraction kettle, sealing under high pressure, and introducing supercritical CO2And contacting with wet gel, extracting and drying. The invention has the beneficial effects that: the process of the invention can be completed in half a day.
Description
Technical Field
The invention belongs to the technical field of macromolecules, and particularly relates to a supercritical drying preparation method of a silicon dioxide aerogel thermal insulation material.
Background
Silica aerogel is a light nano-porous material with a controllable structure, and has many excellent properties, such as high porosity, high specific surface area, low density, low thermal conductivity, and the like. Silica aerogel prepared at home and abroad is usually prepared by taking methyl orthosilicate, ethyl orthosilicate or water glass as raw materials and adopting a sol-gel method and drying under normal pressure, for example, mesoporous silica aerogel materials are prepared by taking organic or inorganic silicon sources as precursors in Chinese patents 200810042222.4, 200910042159.5, 20123519. X, CN201210121968.0, CN201210114691.9 and the like. The method has the common problems of long preparation period, incapability of preparing hydrophilic materials, weak continuous production capacity and the like, and is not beneficial to large-scale operation.
Chen nations, Zhang Jun et al (Chinese patent, application No. 201210078237.2) disclose a method for preparing silica aerogel by aging and supercritical drying of tetraethoxysilane and silica sol as raw materials. However, the temperature of the supercritical drying mode is up to 250 ℃, the pressure is 22MPa, a large amount of energy is consumed, the operation is dangerous, and the cost of the aerogel is greatly increased by adopting tetraethyl orthosilicate as a silicon source, and the supercritical drying mode is not beneficial to large-scale production; similarly, chinese patent application No. 201510911661.4 discloses a supercritical drying method using a solvent, and the pressure and temperature are relatively high, and the silicon source also uses an expensive organic silicon source, which results in an increase in the production cost of the aerogel.
In summary, the technology for preparing the silica aerogel by supercritical drying at the present stage uses an organic silicon source as a precursor, and the preparation cost is high, so that the price of the silica aerogel in the current market is high.
Disclosure of Invention
The invention aims to provide a supercritical drying preparation method of low-density silicon dioxide aerogel, which greatly reduces the solvent exchange time and the production cost and shortens the preparation period by supercritical drying.
The technical scheme adopted by the invention for solving the technical problems is as follows: a supercritical drying preparation method of a silicon dioxide aerogel thermal insulation material is characterized by comprising the following steps: the method comprises the following steps:
1) firstly, diluting a water glass solution by using a certain amount of deionized water;
2) slowly adding the diluted water glass solution into a concentrated hydrochloric acid solution, and continuously stirring to uniformly mix the diluted water glass solution and the concentrated hydrochloric acid solution to obtain a strong-acid silica sol;
3) rotationally evaporating partial water of the acidic silica sol solution, taking out, adding a water-soluble polar solvent with low surface tension, stirring to uniformly mix, and adding a certain amount of the water glass solution obtained in the step 1) to adjust the pH value of the solution to 5.5-6 to form gel;
4) adding a water-soluble polar solvent into the gel obtained in the step 3), aging the gel for 2-12 hours, then placing the obtained wet gel into an extraction kettle, sealing the extraction kettle at high pressure, and introducing supercritical CO2Contacting with wet gel, extracting and drying for 2-5 h.
According to the scheme, the water glass solution in the step 1) is sodium water glass, lithium water glass or potassium water glass, the modulus of the water glass solution is 2.5-3.55, and the volume ratio of the water glass solution to deionized water is 1: 0.5-1: 3.
According to the scheme, the concentration of the concentrated hydrochloric acid used in the step 2) is 8-12mol/L, and the stirring speed is 300-600 r/min.
According to the scheme, the concentration of the concentrated hydrochloric acid used in the step 2) is 12 mol/L.
According to the scheme, the pH value of the strong-acid silica sol obtained in the step 2) is less than 1.5.
According to the scheme, the rotary evaporation temperature in the step 3) is 40-75 ℃, and the rotary evaporation time is 2-15 min.
According to the scheme, the water-soluble polar solvent in the step 3) and the step 4) is ethanol, methanol, isopropanol, propanol or acetone.
According to the scheme, the water glass solution in the step 3) is sodium water glass, lithium water glass or potassium water glass, and the concentration of the water glass solution can be 3-5.5 mol/L.
According to the scheme, the temperature in the extraction kettle in the step 4) can be 35-45 ℃, and the pressure can be 7.4-8.5 MPa.
The invention adopts cheap water glass as a silicon source, and the silica sol can be mutually dissolved with organic solvents such as ethanol and the like by modifying the pH value of the silica sol to form sol and gel which take the organic solvents as main solvents. By consulting relevant documents, the ratio of the solubility of the solvent of supercritical carbon dioxide to ethanol and the like to the solubility of water is about 10, and the organic solvent and water can be extracted just once, so that the aim of solvent exchange is fulfilled. The fluid in the pores of the gel is totally changed into CO after the extraction is finished2CO can be made by changing the temperature and pressure2The supercritical state is directly changed into the gaseous state, and the capillary pressure is always 0 during the process again, so that the high-quality silicon dioxide aerogel is obtained.
The invention has the beneficial effects that: the method takes cheap industrial water glass as a precursor, adopts an innovative process flow, takes an organic solvent as a main solvent thereof, obtains wet gel, and greatly shortens the solvent exchange time and the preparation cost. Most of the silicon dioxide aerogels sold in the market at present are prepared by a supercritical drying mode, a silicon source used by the silicon dioxide aerogels is tetraethyl orthosilicate, and the price of the reagent is high and is more than 100 times that of water glass. Part of aerogel is prepared by adopting a normal pressure drying mode, although the mode can also use water glass as a silicon source, the method can only prepare hydrophobic aerogel (which cannot resist high temperature and is used below 250 ℃), can not prepare high temperature resistant clear water type aerogel, the preparation period is long (more than 1.5 days), and the process can be completed in half a day.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
1) 70mL of sodium water glass (3.55 die, 32.16%) was diluted with 70mL of deionized water and stirred well to give solution A. Slowly pouring the solution A into 20mL of undiluted concentrated hydrochloric acid (12mol/L), stirring while adding (the stirring speed is 300-600 r/min) to obtain a strongly acidic silica sol solution B, wherein the pH value of the strongly acidic silica sol is less than 1.5;
2) taking 100mL of the acidic silica sol, placing the acidic silica sol in a rotary evaporator, setting the temperature to be 50 ℃, and carrying out rotary evaporation for 10 minutes to obtain 70mL of silica sol, taking out the silica sol, adding 70mL of absolute ethyl alcohol into the silica sol, and carrying out magnetic stirring to uniformly mix the silica sol and the absolute ethyl alcohol. Then dropwise adding A into the solution, adjusting the pH value of the solution to 6, and forming gel within 20 min;
3) adding anhydrous ethanol into the formed gel, aging for 4 hr, placing the gel in autoclave, and performing supercritical CO at 7.4Mpa and 35 deg.C2Extracting and drying for 2 h. And finally obtaining the hydrophilic silica aerogel thermal insulation material. The density thereof is as follows: 0.088g/cm3The porosity: 96%, thermal conductivity: 0.019W/m.K.
Example 2
1) 70mL of lithium water glass (3.4 model, 30.64%) was diluted with 70mL of deionized water and stirred to obtain solution A. Slowly pouring the mixed solution into 20mL of undiluted concentrated hydrochloric acid (12mol/L), stirring while adding (the stirring speed is 300-600 r/min) to obtain a strong-acid silica sol solution, wherein the pH value of the obtained strong-acid silica sol is less than 1.5;
2) taking 100mL of the acidic silica sol, placing the acidic silica sol in a rotary evaporator, setting the temperature to be 60 ℃, and carrying out rotary evaporation for 5 minutes to obtain 70mL of silica sol, taking out the silica sol, adding 70mL of anhydrous methanol into the silica sol, and carrying out magnetic stirring to uniformly mix the silica sol and the anhydrous methanol. Then dropwise adding the solution A obtained in the step 1), adjusting the pH value of the solution to 6, and forming gel within 15 min;
3) to the direction ofAdding anhydrous methanol into the formed gel, aging for 3 hr, placing the gel in an autoclave, and performing supercritical CO treatment at 7.6Mpa and 38 deg.C2Extracting and drying for 3 h. And finally obtaining the hydrophilic silica aerogel thermal insulation material. The density thereof is as follows: 0.092g/cm3The porosity: 95.82%, thermal conductivity: 0.020W/m.K.
Example 3
1) 70mL of potassium silicate glass (3.2 model, 29.8%) was diluted with 70mL of deionized water and stirred well to obtain solution A. Slowly pouring the mixed solution into 20mL of concentrated hydrochloric acid (10mol/L), stirring while adding (the stirring speed is 300-600 r/min) to obtain a strong-acid silica sol solution, wherein the pH value of the obtained strong-acid silica sol is less than 1.5;
2) taking 100mL of the acidic silica sol, placing the acidic silica sol in a rotary evaporator, setting the temperature to be 70 ℃, and carrying out rotary evaporation for 3 minutes to obtain 70mL of silica sol, taking out the silica sol, adding 70mL of acetone into the silica sol, and carrying out magnetic stirring to uniformly mix the silica sol and the acetone. Then dropwise adding the solution A obtained in the step 1), adjusting the pH value of the solution to 6, and forming gel within 20 min;
3) adding acetone into the formed gel, aging for 6 hr, placing the gel in an autoclave, and performing supercritical CO at 8Mpa and 45 deg.C2Extracting and drying for 4 h. And finally obtaining the hydrophilic silica aerogel thermal insulation material. The density thereof is as follows: 0.103g/cm3The porosity: 95.32%, thermal conductivity: 0.022W/m.K.
Example 4
1) 70mL of sodium water glass (3.24 die, 31.89%) was diluted with 70mL of deionized water and stirred well to give solution A. Slowly pouring the mixed solution into 20mL of undiluted concentrated hydrochloric acid (12mol/L), stirring while adding (the stirring speed is 300-600 r/min) to obtain a strong-acid silica sol solution, wherein the pH value of the obtained strong-acid silica sol is less than 1.5;
2) taking 100mL of the acidic silica sol, placing the acidic silica sol in a rotary evaporator, setting the temperature to be 50 ℃, and carrying out rotary evaporation for 10 minutes to obtain 70mL of silica sol, taking out the silica sol, adding 70mL of absolute ethyl alcohol into the silica sol, and carrying out magnetic stirring to uniformly mix the silica sol and the absolute ethyl alcohol. Then dropwise adding the solution A obtained in the step 1), adjusting the pH value of the solution to 5.5, and forming gel within 25 min;
3) adding anhydrous ethanol into the formed gel, aging for 4 hr, placing the gel in autoclave, and performing supercritical CO at 8.5Mpa and 35 deg.C2Extracting and drying for 4 h. And finally obtaining the hydrophilic silica aerogel thermal insulation material. The density thereof is as follows: 0.095g/cm3The porosity: 95.68%, thermal conductivity: 0.023W/m.K.
Claims (6)
1. A supercritical drying preparation method of a silicon dioxide aerogel thermal insulation material is characterized by comprising the following steps: the method comprises the following steps:
1) firstly, diluting a water glass solution by using a certain amount of deionized water; the water glass solution is sodium water glass, lithium water glass or potassium water glass, the modulus of the water glass solution is 2.5-3.55, and the volume ratio of the water glass solution to the deionized water is 1: 0.5-1: 3;
2) slowly adding the diluted water glass solution into a concentrated hydrochloric acid solution, continuously stirring the obtained strong-acid silica sol until the pH value is less than 1.5, and uniformly mixing the silica sol and the solution to obtain strong-acid silica sol;
3) rotationally evaporating partial water of the acidic silica sol solution, taking out, adding a water-soluble polar solvent with low surface tension, stirring to uniformly mix, and adding a certain amount of the water glass solution obtained in the step 1) to adjust the pH value of the solution to 5.5-6 to form gel; the rotary evaporation temperature is 40-75 deg.C, and the rotary evaporation time is 2-15 min;
4) adding a water-soluble polar solvent into the gel obtained in the step 3), aging the gel for 2-12 hours, then placing the obtained wet gel into an extraction kettle, sealing the extraction kettle at high pressure, and introducing supercritical CO2Contacting with wet gel, extracting and drying for 2-5 h.
2. The supercritical drying preparation method of a silica aerogel thermal insulation material according to claim 1, characterized in that: the concentration of the concentrated hydrochloric acid used in the step 2) is 8-12mol/L, and the stirring speed is 300-600 r/min.
3. The supercritical drying preparation method of a silica aerogel thermal insulation material according to claim 2, characterized in that: the concentration of the concentrated hydrochloric acid used in the step 2) is 12 mol/L.
4. The supercritical drying preparation method of a silica aerogel thermal insulation material according to claim 1, characterized in that: the water-soluble polar solvent in the step 3) and the step 4) is ethanol, methanol, isopropanol, propanol or acetone.
5. The supercritical drying preparation method of a silica aerogel thermal insulation material according to claim 1, characterized in that: the water glass solution in the step 3) is sodium water glass, lithium water glass or potassium water glass, and the concentration of the water glass solution is 3-5.5 mol/L.
6. The supercritical drying preparation method of a silica aerogel thermal insulation material according to claim 1, characterized in that: in the step 4), the temperature in the extraction kettle is 35-45 ℃, and the pressure is 7.4-8.5 MPa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710454634.8A CN107128933B (en) | 2017-06-15 | 2017-06-15 | Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710454634.8A CN107128933B (en) | 2017-06-15 | 2017-06-15 | Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107128933A CN107128933A (en) | 2017-09-05 |
| CN107128933B true CN107128933B (en) | 2020-01-14 |
Family
ID=59735096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710454634.8A Active CN107128933B (en) | 2017-06-15 | 2017-06-15 | Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107128933B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108862286B (en) * | 2018-07-05 | 2020-06-30 | 江苏泛亚微透科技股份有限公司 | Flame-retardant and heat-insulating elastic silicon dioxide aerogel sheet and sheet for thermal management system of automobile lithium ion power battery |
| CN113401910A (en) * | 2021-07-30 | 2021-09-17 | 江苏泛亚微透科技股份有限公司 | Silicon dioxide aerogel and low-corrosion preparation method thereof |
| CN115806427A (en) * | 2022-12-13 | 2023-03-17 | 中化学华陆新材料有限公司 | Low-cost SiO 2 Method for producing aerogels |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5264197A (en) * | 1991-12-20 | 1993-11-23 | Yazaki Corporation | Sol-gel process for providing a tailored gel microstructure |
| JP3712410B2 (en) * | 1993-08-31 | 2005-11-02 | ビーエーエスエフ アクチェンゲゼルシャフト | Hydrophobic silicate airgel |
| KR100785521B1 (en) * | 2006-07-03 | 2007-12-13 | 한국생산기술연구원 | Method for preparing surface-modified aerogel and surface-modified aerogel therefrom |
| CN104030301B (en) * | 2014-06-18 | 2016-03-23 | 金承黎 | A kind of silica aerogel material and preparation method thereof |
| CN105502417A (en) * | 2014-12-02 | 2016-04-20 | 北京建工新型建材有限责任公司 | Preparation method for low-density silica aerogel |
| CN106082243B (en) * | 2016-06-12 | 2018-11-23 | 伊科纳诺（北京）科技发展有限公司 | A kind of normal pressure fast preparation method of hydrophobic silica aerogel powder |
-
2017
- 2017-06-15 CN CN201710454634.8A patent/CN107128933B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107128933A (en) | 2017-09-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103833041B (en) | A kind of constant pressure and dry prepares the method for flexible silica aerogel block | |
| CN107128933B (en) | Supercritical drying preparation method of silicon dioxide aerogel thermal insulation material | |
| CN104261797A (en) | Glass fiber reinforced TiO2-SiO2Preparation method of composite aerogel heat insulation material | |
| KR101064869B1 (en) | Method for manufacturing flexible silica aerogel | |
| CN106745002B (en) | A kind of method that co-precursor method constant pressure and dry prepares block aerosil | |
| CN103706342A (en) | Amino hybridized SiO2Aerogel materials and uses thereof | |
| CN101559954B (en) | Method for preparing mesoporous molecular sieve with high hydrothermal stability by taking ionic liquid as template agent | |
| CA2646043A1 (en) | Method for the production of glassy monoliths via the sol-gel process | |
| CN104761235A (en) | Low temperature resistant glass fiber reinforced SiO2Preparation method of aerogel composite material | |
| CN104016369B (en) | A kind of method utilizing kaolin synthesizing high-stability ordered mesoporous material Al-SBA-15 | |
| KR20190028163A (en) | Preparation method of metal oxide-silica complex aerogel and metal oxide-silica complex aerogel produced by the same | |
| CN103274665B (en) | Preparation method for alumina nanofibre-reinforced SiO2 aerogel | |
| CN103848427B (en) | A kind of high dispersive precipitated silica and preparation method thereof | |
| CN101289191B (en) | Transparent meso-porousearth silicon gel monolithi material | |
| CN107032319B (en) | A kind of high specific area carbon aerogel and preparation method thereof | |
| CN114477194A (en) | Method for preparing hydrophobic silica aerogel based on chemical vapor deposition | |
| CN109650395A (en) | The method that sublimed method prepares aerosil | |
| CN115432710A (en) | Preparation method of ultra-low density silicon dioxide aerogel block | |
| CN102765726B (en) | A kind of take rice hull ash as the method that aerosil prepared by raw material | |
| CN111233379B (en) | Foamed geopolymer/aerogel composite heat-insulating material and preparation method thereof | |
| CN101289192B (en) | Method for preparing transparent meso-porousearth silicon gel monolithi material | |
| CN104477983A (en) | Preparation method for hierarchical porous titanium dioxide block | |
| CN108584965B (en) | Method for rapidly preparing aerogel by accelerating solvent extraction | |
| CN110642257B (en) | Method for preparing silicon dioxide aerogel by using silicon micropowder | |
| CN111099876A (en) | Preparation method of low-cost silicon dioxide aerogel composite flexible heat insulation material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |