Method for producing an aerogel

Abstract

The present invention provides a method for producing an aerogel, comprising the steps of: reacting water glass with a first substance in a reaction tank to obtain a hydrogel; after moving the hydrogel to a solvent replacement tank, reacting the hydrogel with a second substance in the solvent replacement tank to obtain an organogel; and after moving the organogel to a dryer, drying the organogel in the dryer to obtain an aerogel powder.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an aerogel.

Background Art

[0002] Generally, an aerogel has high porosity reaching up to 99%, a low refractive index of 1.01 to 1.1, a high transparency of 90% or more, a specific surface area of 1000 m 2 / g or more, and very low thermal conductivity of 0.02 W / mK or less, and is an advanced material having such characteristics.

[0003] An aerogel having such characteristics is highly evaluated as a material for energy and environmental materials and for the advancement of the electronics industry due to its unique thermal, electrical, and optical properties. Therefore, applications of this substance to superinsulating materials, acoustic delay materials, catalyst carriers, and interlayer insulating materials for high-speed circuits of next-generation semiconductors have been attempted.

[0004] Despite such excellent characteristics, aerogels have had many difficulties in the manufacturing process for mass production for commercial use. The manufacturing time is long, and a large amount of capital must be invested in constructing production facilities. Also, the quality of aerogels produced in large quantities may be lower than that produced in small quantities in a laboratory.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One object of the present invention is to provide a method for manufacturing an aerogel that can shorten the production time and improve the efficiency of production equipment.

[0006] Another object of the present invention is to provide a method for manufacturing an aerogel that can improve the quality of the final product along with the above-mentioned improvement in productivity.

Means for Solving the Problem

[0007] A method for manufacturing an aerogel according to one aspect of the present invention for realizing the above-described problem includes a step of reacting water glass and a first substance in a reaction tank to obtain a hydrogel; a step of moving the hydrogel to a solvent replacement tank and then reacting the hydrogel with a second substance in the solvent replacement tank to obtain an organogel; and a step of moving the organogel to a dryer and then drying the organogel in the dryer to obtain an aerogel powder.

[0008] Here, the first substance includes pure water, nitric acid, and HMDS, and these can be sequentially introduced into the reaction tank.

[0009] In one specific example, the method includes a step of reacting water glass and a first substance in a reaction tank to obtain a hydrogel; a step of moving the hydrogel to a solvent replacement tank and then reacting the hydrogel with a second substance in the solvent replacement tank to obtain an organogel; and a step of moving the organogel to a dryer and then drying the organogel in the dryer to obtain an aerogel powder, the first substance includes pure water, nitric acid, and HMDS, no second substance is introduced into the reaction tank, and the second substance includes n-hexane.

[0010] Here, a step of cleaning the reaction tank after the hydrogel is moved to the solvent replacement tank may be further provided.

[0011] Here, the step of cleaning the reaction tank after the hydrogel is moved to the solvent replacement tank may include a step of spraying pure water onto the inner surface of the reaction tank while rotating an injection nozzle 360°.

[0012] Here, the second substance may include n-hexane.

[0013] There is no organogel in the reaction tank.

[0014] Here, the solvent replacement tank may be made of a material having lower corrosion resistance, acid resistance, and high-temperature strength than the reaction tank.

[0015] Here, it further includes a step of discharging the waste water generated together with the organogel in the solvent replacement tank before moving the organogel to the dryer, and the step of discharging the waste water may include a step of controlling the opening and closing of a discharge valve for discharging the waste water based on the water level of the waste water measured by a level sensor by a controller.

[0016] Here, the level sensor may be a radar-type sensor installed in the solvent replacement tank and emitting electromagnetic waves in a direction facing the interface between the organogel layer and the waste water layer.

[0017] Here, a step of cleaning the solvent replacement tank after the organogel is moved to the dryer may be further provided.

[0018] Here, the step of cleaning the solvent replacement tank after the organogel is moved to the dryer may include a step of injecting n-hexane onto the inner surface of the solvent replacement tank while rotating an injection nozzle 360°.

Advantages of the Invention

[0019] According to the method for producing an aerogel according to the present invention configured as described above, after obtaining a hydrogel from water glass in a reaction tank, the hydrogel is moved to a solvent replacement tank to obtain an organogel, and then an aerogel powder is obtained through drying in a dryer. Thus, while the substitution process proceeds for a long time in the solvent replacement tank, the next reaction can be carried out in the reaction tank, significantly shortening the overall production time.

[0020] In addition, since the organogel is separately produced in the solvent replacement tank, structurally, the disturbance of raw material mixing caused by the remaining organogel in the reaction tank can be blocked when the organogel is produced in the reaction tank. Because there is no such disturbance, the quality of the finally produced aerogel can also be improved.

Brief Description of the Drawings

[0021] FIG. 1 is a flowchart showing a method for producing an aerogel according to an embodiment of the present invention.

[0022] FIG. 2 is a conceptual diagram showing the arrangement of manufacturing equipment 100 and material input for implementing the manufacturing method of FIG. 1 together.

[0023] FIG. 3 is a conceptual diagram showing the specific structure of the solvent replacement tank 130 of FIG. 2.

Best Mode for Carrying Out the Invention

[0024] In the first specific example, a step of reacting sodium silicate and a first substance in a reaction tank to obtain a hydrogel;

[0025] After moving the hydrogel to a solvent replacement tank, a step of reacting the hydrogel with a second substance in the solvent replacement tank to obtain an organogel; and

[0026] After moving the organogel to a dryer, a step of drying the organogel in the dryer to obtain an aerogel powder, relating to a method for producing an aerogel.

[0027] In the second specific example, a step of reacting sodium silicate and a first substance in a reaction tank to obtain a hydrogel;

[0028] After moving the hydrogel to a solvent replacement tank, a step of reacting the hydrogel with a second substance in the solvent replacement tank to obtain an organogel; and

[0029] After moving the organogel to a dryer, drying the organogel in the dryer to obtain an air powder,

[0030] The first substance includes pure water, nitric acid, and HMDS,

[0031] No second substance is added to the reaction tank,

[0032] The second substance includes n-hexane, and relates to a method for producing an aerogel. Mode for carrying out the invention

[0033] Hereinafter, a method for producing an aerogel according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this specification, even for different embodiments, the same or similar components are given the same or similar reference numerals, and the description thereof replaces the first description.

[0034] FIG. 1 is a flowchart showing a method for producing an aerogel according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing the arrangement and material input of manufacturing equipment 100 for implementing the manufacturing method of FIG. 1 together.

[0035] Referring to this drawing, the production of aerogel starts from the step (S1) of reacting water glass with the first substance.

[0036] The water glass first put into the reaction tank 110 is sodium silicate (Na 2 SiO 3 ). The water glass can be measured in the amount required for the reaction and waited for before being put into the reaction tank 110 from the storage tank. The water glass can be put into the reaction tank 110 by gravity in a short time.

[0037] After the water glass is put into the reaction tank 110, the first substance is put into the reaction tank 110. Specifically, the first substance can include demineralized water, nitric acid, and HMDS (Hexamethyldisilazane). These must be put into the reaction tank 110 sequentially.

[0038] Water glass and pure water do not mix well due to a large difference in specific gravity, so an agitator can be installed in the reaction tank 110 to stir them so that they mix sufficiently. The raw materials can be introduced in such a way that nitric acid (HNO 3 , 60%) is introduced every 1 minute while the water glass and pure water are being stirred, and HMDS is introduced 3 minutes later. After HMDS is introduced, the reaction can proceed for about 5 minutes. It is preferable that the agitator operates continuously during these reactions so that they mix well.

[0039] When pure water is added to water glass, the water glass is hydrolyzed to produce an aqueous solution of water glass. When nitric acid is added here, a change in properties occurs to form a gel, and the neutralization of the pH concentration begins. Additionally, when HMDS is added, the change to the gel is accelerated. The total process time in the reaction tank 110 is within 20 minutes.

[0040] For the reaction between water glass and the first substance, the internal temperature of the reaction tank 110 needs to be about 45 - 50°C. For this purpose, a heating jacket surrounding the housing of the reaction tank 110 uses hot water to heat the reaction tank 110. When the reaction proceeds smoothly, the internal temperature of the reaction tank 110 can reach about 60°C.

[0041] The reaction formula for the above reaction is shown below.

[0042] Na 2 SiO 3 +2HNO 3 +HMDS → 2NaNO 3 +NH 3 +Aerogel(Si 3 (CH 3 ) 6 O 3 )n

[0043] Referring to the above reaction formula, when HMDS and nitric acid react, ammonia (NH3 ) is generated, and this gas is processed by a scrubber 190. The treated wastewater is sent to a wastewater treatment plant for treatment there. Whether the reaction in the reaction tank 110 is completed can be determined by checking the pH of the reactants.

[0044] Upon completion of the reaction, a hydrogel is formed in the reaction tank 110. The generated hydrogel is discharged from the reaction tank 110.

[0045] After the reaction tank 110 is emptied, the reaction tank 110 can be washed. For washing, an injection nozzle operates inside the reaction tank 110. The injection nozzle can inject pure water onto the inner surface of the reaction tank 110 while rotating 360°. Thereby, the reaction tank 110 will receive the next input of water glass and the first substance in a clean state after being washed. The washed wastewater is sent to a wastewater treatment device for treatment.

[0046] The hydrogel discharged from the reaction tank 110 moves to another container, namely, a solvent replacement tank 130 (S3). The solvent replacement tank 130 can be manufactured differently from the reaction tank 110 in terms of material. Specifically, the reaction tank 110 must be made of, for example, STS316L in order to withstand corrosion and temperature drop corresponding to strong acids and strong bases. On the other hand, since the solvent replacement tank 130 does not have such requirements, a material of STS304, which has lower corrosion resistance, acid resistance, and high-temperature strength than the reaction tank 110, is sufficient.

[0047] Thereby, the solvent replacement tank 130 can be manufactured at a level of 40% compared to the reaction tank 110 based on the material cost. Since the solvent replacement tank 130 must have a size twice as large as the reaction tank 110, even if they are manufactured separately, the overall cost will be further reduced compared to the case where only one reaction tank 110 is manufactured larger.

[0048] In the solvent replacement tank 130, for example, n - hexane is introduced as the second substance to the hydrogel (S5). The hydrogel undergoes a condensation reaction with n - hexane and is replaced by an organogel and water. The replacement process is completed within about 40 minutes while maintaining a temperature of 50°C at normal pressure. Such a time is about 2 times compared to the time in the reaction tank 110. Water (waste water) is discharged to the waste water treatment device, which will be described with reference to FIG. 3.

[0049] Furthermore, referring to FIGS. 1 and 2, the organogel is transferred to the dryer 150 (S7). After the solvent replacement tank 130 becomes empty, the solvent replacement tank 130 can be washed. This can be done by injecting n - hexane into the solvent replacement tank 130. The n - hexane can be injected to every corner of the inner surface of the solvent replacement tank 130 by the injection nozzle rotating 360°.

[0050] Inside the dryer 150, the organogel becomes aerogel powder through the drying process (S9). Specifically, the organogel introduced into the dryer 150 is stirred under temperature conditions of about 130°C and in a vacuum state. Thereby, n - hexane and residual moisture evaporate, and the organogel undergoes a phase transformation into a solid state. The n - hexane is separated, sent to the condenser 170, liquefied, separated, and can be re - introduced into the solvent replacement tank 130. The reuse rate of n - hexane can be about 90%, and a certain amount must be periodically discharged to maintain the quality. To supplement this, new n - hexane can be additionally mixed with the regenerated n - hexane. Shearing force is applied to the aerogel powder through drying, and its pores are homogenized. The aerogel powder is sent to the silo for storage and can be shipped in the required amount.

[0051] Above, the solvent replacement tank 130 will be further described with reference to FIG. 3. FIG. 3 is a conceptual diagram showing the specific structure of the solvent replacement tank 130 in FIG. 2.

[0052] Referring to this drawing, in the housing 131 of the solvent replacement tank 130, an organogel O and wastewater W are generated by a condensation reaction. Here, the organogel O will be located above the wastewater W due to the difference in specific gravity. The separation of the layers of the organogel O and the wastewater W can be more easily performed by the operation of the stirring device in the housing 131.

[0053] The wastewater W must be discharged to the wastewater treatment device through the discharge valve 133. The discharge valve 133 needs to be controlled to be opened only until the wastewater W is discharged. For this purpose, a controller (not shown) that controls the opening and closing of the discharge valve 133 operates based on the detection result of the level sensor 135.

[0054] The level sensor 135 measures the water level of the wastewater W through measurement with respect to the interface I between the organogel O and the wastewater W. For this purpose, the level sensor 135 may be a radar-type sensor installed in the housing 131. Thereby, the level sensor 135 can emit electromagnetic waves in the direction facing the interface I and measure the height of the interface I in a non-contact manner.

[0055] By the controller controlling the discharge valve 133 based on the detection result of the level sensor 135, the discharge valve 133 can be opened and closed according to the accurate water level of the wastewater W. This can prevent the loss of discharging the organogel O in addition to the wastewater W.

[0056] After the discharge of the wastewater W, the organogel O can be moved to the dryer 150 through another line 137. Also, the ammonia generated in the housing 131 can be moved to the scrubber 190 through a separate line 139.

[0057] The method for manufacturing an aerogel as described above is not limited by the configurations and operating methods of the above-described embodiments. The above embodiments may be configured such that all or part of each embodiment is selectively combined and variously modified.

[0058] <Example>

[0059] After producing a hydrogel by reacting sodium silicate, pure water, nitric acid, and HMDS in a reaction tank, the hydrogel was transferred to a solvent replacement tank and reacted with n-hexane to obtain an organogel. The produced organogel was dried to produce an aerogel powder. As a result of measuring the thermal conductivity of the produced aerogel powder, it was 0.01835 W / mk.

[0060] <Comparative Example>

[0061] After producing a hydrogel by reacting sodium silicate, pure water, nitric acid, HMDS, and n-hexane in a reaction tank, the hydrogel was transferred to a solvent replacement tank to obtain an organogel. The produced organogel was dried to produce an aerogel powder. As a result of measuring the thermal conductivity of the produced aerogel powder, it was 0.02147 W / mk.

Industrial Applicability

[0062] According to the method for producing an aerogel of the present invention, after obtaining a hydrogel from sodium silicate in a reaction tank, the hydrogel is transferred to a solvent replacement tank to obtain an organogel, and then an aerogel powder is obtained through drying with a dryer. Thus, while the substitution process proceeds for a long time in the solvent replacement tank, the next reaction is carried out in the reaction tank, which can significantly shorten the overall production time.

[0063] In addition, since the organogel is separately produced in the solvent replacement tank, structurally, the disturbance of raw material mixing due to the organogel remaining in the reaction tank can be blocked compared to the case where the organogel is produced in the reaction tank. Due to the absence of such disturbance, the quality of the finally produced aerogel can also be improved.

Claims

1. A step of reacting water glass and a first substance in a reaction tank to obtain a hydrogel; After moving the hydrogel to a solvent replacement tank, a step of reacting the hydrogel and a second substance in the solvent replacement tank to obtain an organogel; and After moving the organogel to a dryer, a step of drying the organogel in the dryer to obtain an aerogel powder, The first substance includes pure water, nitric acid, and HMDS, No second substance is introduced into the reaction tank, The second substance includes n-hexane, and a method for producing an aerogel is characterized thereby.

2. The method for producing an aerogel according to claim 1, wherein the pure water, nitric acid, and HMDS are sequentially introduced into the reaction tank.

3. The method for producing an aerogel according to claim 1, further comprising a step of cleaning the reaction tank after the hydrogel is moved to the solvent replacement tank.

4. The step of cleaning the reaction tank after the hydrogel is moved to the solvent replacement tank includes a step of spraying pure water onto the inner surface of the reaction tank while rotating a spray nozzle 360°, and the method for producing an aerogel according to claim 3 is characterized thereby.

5. The method for producing an aerogel according to claim 1, wherein no organogel is present in the reaction tank.

6. The method for producing an aerogel according to claim 1, wherein the solvent replacement tank is made of a material having lower corrosion resistance, acid resistance, and high-temperature strength than the reaction tank.

7. Before moving the organogel to the dryer, the method further includes a step of discharging wastewater generated together with the organogel in the solvent replacement tank, The step of discharging the wastewater includes a step of controlling the opening and closing of a discharge valve for discharging the wastewater based on the water level of the wastewater measured by a level sensor by a controller, and the method for producing an aerogel according to claim 1 is characterized thereby.

8. The method for producing an aerogel according to claim 7, wherein the level sensor is a radar-type sensor installed in the solvent replacement tank and emitting electromagnetic waves in a direction facing the interface between the organogel and the wastewater layer.

9. The method for producing an aerogel according to claim 1, further comprising a step of cleaning the solvent replacement tank after the organogel is moved to the dryer.

10. The step of cleaning the solvent replacement tank after the organogel is transferred to the dryer includes a step of injecting n-hexane onto the inner surface of the solvent replacement tank while rotating the injection nozzle 360°, The method for producing an aerogel according to claim 9, characterized in that.

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