阅读说明：本技术 合成石英粉末的制备方法 (Method for preparing synthetic quartz powder ) 是由 金胤秀 朴锺乐 于 2018-12-14 设计创作，主要内容包括：本发明涉及一种合成石英粉末的制备方法,根据本发明的一实施例的合成石英粉末的制备方法包括如下步骤：制备碱性硅酸盐溶液；稀释并冷却碱性硅酸盐溶液；将碱性硅酸盐溶液离子交换而制备胶体二氧化硅溶胶水溶液；向胶体二氧化硅溶胶水溶液添加第一添加剂而进行解离溶出及离子交换；向胶体二氧化硅溶胶水溶液添加第二添加剂而使二氧化硅的粒径生长；对胶体二氧化硅溶胶水溶液进行过滤、浓缩、添加而制备湿凝胶；去除湿凝胶中含有的水分而制备干燥硅胶；对干燥硅胶进行加工而制备合成石英粉末。(The present invention relates to a method for preparing synthetic quartz powder, the method for preparing synthetic quartz powder according to an embodiment of the present invention includes the steps of: preparing an alkali silicate solution; diluting and cooling the alkali silicate solution; ion-exchanging the alkali silicate solution to prepare a colloidal silica sol aqueous solution; adding a first additive to the colloidal silica sol aqueous solution to perform dissociation dissolution and ion exchange; adding a second additive to the colloidal silica sol aqueous solution to grow the particle size of the silica; filtering, concentrating and adding the colloidal silica sol aqueous solution to prepare wet gel; removing water contained in the wet gel to prepare a dry silica gel; the dried silica gel was processed to prepare synthetic quartz powder.)

1. A method for producing a synthetic quartz powder, comprising the steps of:

(a) hydrolyzing hydrophilic silica and a water-soluble alkali metal hydroxide in ultrapure water, and then stirring the same for one hour or more, thereby preparing an alkali silicate solution having a silica concentration of 15% or more;

(b) diluting the alkali silicate solution with ultrapure water to dilute the concentration of silica and performing primary cooling, and then performing secondary cooling at a temperature ranging from 15 to 20 ℃ by selecting cooling in a reactor itself using a cooler or a cooling method using a separate cooling unit, thereby preparing an alkali silicate aqueous solution at a temperature ranging from 0 to 5 ℃;

(c) injecting the cooled alkali silicate solution into an ion exchange column, and performing H + type cation exchange treatment to prepare a colloidal silica sol aqueous solution;

(d) adding a first additive to the colloidal silica sol aqueous solution, and stirring the same to perform dissociation dissolution and ion exchange;

(e) adding a second additive into the colloidal silica sol aqueous solution, and stirring at the temperature of 20-80 ℃ so as to grow the particle size of the colloidal silica;

(f) concentrating the colloidal silica sol aqueous solution using a filtration membrane, and further adding ammonia water to prepare a wet gel;

(g) drying to remove moisture contained in the wet gel after evaporating the wet gel, thereby preparing a dried silica gel;

(h) the dried silica gel is processed to prepare a synthetic quartz powder.

2. The method of manufacturing synthetic quartz powder according to claim 1,

the content of metal impurities in the hydrophilic silicon dioxide in the step (a) is less than 1ppm, and the range of the specific surface area is 90-300 m²Silica fume and fused silica in a ratio of/g.

3. The method of manufacturing synthetic quartz powder according to claim 1,

the mole ratio of the hydrophilic silica to the alkali metal hydroxide in the step (a) is 1 to 4.5, and the hydrophilic silica is reacted with the alkali metal oxide at the above mole ratio.

4. The method of manufacturing synthetic quartz powder according to claim 1,

in the (b) step, the temperature of the ultrapure water is 0 to 15 ℃.

5. The method of manufacturing synthetic quartz powder according to claim 1,

the concentration of silica in the aqueous alkali silicate solution prepared in the (b) step is 1 to 6.5%.

6. The method of manufacturing synthetic quartz powder according to claim 1,

the ion exchange column in the step (c) is configured to have an air barrier type closed structure, thereby preventing a phenomenon that the carbon dioxide of the alkali silicate aqueous solution is absorbed to cause the silicic acid to precipitate as a gel.

7. The method of manufacturing synthetic quartz powder according to claim 1,

the first additive in the step (d) is any one of hydrochloric acid, nitric acid, sulfuric acid and hydrogen peroxide.

8. The method of manufacturing synthetic quartz powder according to claim 1,

the second additive in the step (e) is any one of ammonia water and amine.

9. The method of manufacturing synthetic quartz powder according to claim 1,

in the (g) step, the wet gel is heated by an infrared heater in an inert gas state to evaporate moisture contained in the wet gel, followed by drying in a vacuum state.

Technical Field

The present invention relates to a method for preparing synthetic quartz powder, and more particularly, to a method for preparing synthetic quartz powder for preparing synthetic quartz glass powder by a Sol-gel (Sol-gel) preparation method.

Background

In recent years, strict control has been performed on the purity of silica glass products used in the field of optical communication, semiconductor industry, and the like.

For such high-purity silica glass, there is a method of producing a material for glass articles, as follows: a material for producing glass products, which uses, as a raw material, a sandy natural quartz powder (alternatively referred to as quartz sand) obtained by pulverizing natural quartz; and a method for producing a material for glass products using a steam block obtained by causing steam generated by decomposition of silicon tetrachloride in an oxyhydrogen flame to adhere to and grow on a substrate.

However, although the above-described method for producing synthetic quartz using a hydrogen-oxygen flame of silicon tetrachloride can be mass-produced, since impurities such as fine bubbles are contained, problems occur in the semiconductor industry such as photomasks and crucibles for single crystal growth, and in order to solve such problems, patent document 1 is referred to, and the following is specifically described with reference to patent document 1.

Patent document 1 relates to a method for producing a high-purity synthetic silica powder, which, according to patent document 1, comprises: a first step of reacting Fumed silica (Fumed silica) with an aqueous alkali metal hydroxide solution to produce an aqueous alkali metal silicate solution; a second step of subjecting the obtained alkali metal silicate aqueous solution to dealkalization treatment to obtain a silica aqueous solution having a pH of 9 to 11; a third step of subjecting the obtained silica aqueous solution to cation exchange treatment so that the pH of the aqueous solution is 2 to 3; a fourth step of concentrating and gelling the obtained silica aqueous solution; a fifth step of drying the obtained gelled product; a sixth step of pulverizing the dried gel to obtain a pulverized product; a seventh step of treating the pulverized material with an acidic solution; and an eighth step of sintering the pulverized product treated with the acidic aqueous solution at 1100 to 1300 ℃ using a dry gas.

However, although the above-mentioned patent document 1 prevents the increase in viscosity of the ion exchange resin when the ion exchange resin of the aqueous silica solution passes and the clogging caused by gelation caused thereby by the adjustment of the acid-base value (pH), the effect is weak, and when the ion exchange resin of the aqueous silica solution passes through the ion exchange resin, the durability of the ion exchange resin is low, so that it is cumbersome to have to frequently replace the ion exchange resin, and there is a problem that the price of the synthetic quartz powder is increased by frequently replacing the ion exchange resin.

[ Prior art documents ]

[ patent document ]

(patent document 1) Japanese patent laid-open publication No. 6,141,710

Disclosure of Invention

The object of the present invention is to provide a method for producing synthetic quartz powder for producing synthetic quartz glass powder by a sol-gel production method.

In order to solve the above problems, a method of manufacturing a synthetic quartz powder according to an embodiment of the present invention may include the steps of: (a) hydrolyzing hydrophilic silica and a water-soluble alkali metal hydroxide in ultrapure water, and then stirring the same for one hour or more, thereby preparing an alkali silicate solution having a silica concentration of 15% or more; (b) diluting the alkali silicate solution with ultrapure water to dilute the concentration of silica and performing primary cooling, and then performing secondary cooling at a temperature ranging from 15 to 20 ℃ by selecting a method such as cooling in a reactor itself using a cooler or cooling using a separate cooling unit, thereby preparing an alkali silicate aqueous solution at a temperature ranging from 0 to 5 ℃; (c) injecting the cooled alkali silicate solution into an ion exchange column, and performing H + type cation exchange treatment to prepare a colloidal silica sol aqueous solution; (d) adding a first additive to the colloidal silica sol aqueous solution, and stirring the same to perform dissociation dissolution and ion exchange; (e) adding a second additive into the colloidal silica sol aqueous solution, and stirring at the temperature of 20-80 ℃ so as to grow the particle size of the colloidal silica; (f) concentrating the colloidal silica sol aqueous solution using a filtration membrane, and further adding ammonia water to prepare a wet gel; (g) drying to remove moisture contained in the wet gel after evaporating the wet gel, thereby preparing a dried silica gel; (h) the dried silica gel is processed to prepare a synthetic quartz powder.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the hydrophilic silica in the step (a) may be selected such that the content of metal impurities is less than 1ppm and the specific surface area is in a range of 90 to 300m²Silica fume and fused silica in a ratio of/g.

In the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the hydrophilic silica in the step (a) may be any one of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

In the method of manufacturing synthetic quartz powder according to one embodiment of the present invention, the hydrophilic silica and the alkali metal oxide may be reacted at a molar ratio of the hydrophilic silica to the alkali metal hydroxide in the step (a) of 1 to 4.5.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, in the step (b), the temperature of the ultrapure water may be in the range of 0 to 15 ℃.

And, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the alkali silicate aqueous solution prepared in the (b) stepCan be prepared into silicon dioxide (SiO)₂) The concentration of (A) is in the range of 1 to 6.5%.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the ion exchange column in the step (c) may be configured as an air barrier type closed structure, thereby preventing a phenomenon in which the silicic acid is precipitated as a gel by absorbing carbon dioxide of the alkali silicate aqueous solution.

Further, in the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, before the alkali silicate aqueous solution is injected into the ion exchange column in the step (c), an inert gas may be injected into the inside of the ion exchange column by vacuum replacement or forced air blowing, thereby removing air existing inside the ion exchange column.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the first additive in the step (d) may be added by selecting any one of hydrochloric acid, nitric acid, sulfuric acid, and hydrogen peroxide.

In the method for producing a synthetic quartz powder according to an embodiment of the present invention, in the step (d), the alkali metal and the polyvalent metal ion bonded to the inside of the silicic acid polymer particles may be dissociated and eluted.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the second additive in the step (e) may be added by selecting any one of ammonia water and amine.

Also, in the method of manufacturing the synthetic quartz powder according to an embodiment of the present invention, the second additive may use a chemical solution of an electronic grade or more, thereby managing a dropping rate of less than 1L/min to prevent local gelation of the colloidal silica sol aqueous solution.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, in the step (e), the particle size of the colloidal silica may be grown to 10nm or more.

In the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the filter membrane of the step (f) may be provided to have a void size of 10 to 15nm and may be formed of a chemical resistant material.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the ammonia water of the step (f) may use a chemical solution of an electronic grade or more, and the dropping rate is controlled to be less than 1L/min.

Also, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, after the ammonia water is added in the step (f), a wet gel may be prepared by high frequency, infrared heating, hot air heating.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, in the high frequency, infrared heating, hot wind heating manner, heating is performed to less than 160 ℃ to prepare a wet gel.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, in the (g) step, the wet gel may be heated by an infrared heater in an inert gas state where a partial pressure of steam is low, thereby evaporating moisture contained in the wet gel, and dried in a vacuum state.

Also, in the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the step (h) may include the steps of: (h) -1, pulverizing the dried silica gel to produce fine particles of silica gel; (h) washing the fine particles of the silica gel with either an acidic aqueous solution or ultrapure water; (h) -3, drying the washed silica gel particles; (h) and 4, sintering the dried silica gel.

Further, in the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the pulverizing step is performed by pulverizing the dried silica gel using a pulverizing structure selected from any one of a roll mill, a ball mill, a disc mill, and a jet mill, and may be formed using zirconium or a synthetic quartz material.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the acidic aqueous solution may be any one selected from hydrochloric acid, nitric acid, and sulfuric acid having an electronic grade or higher, and the heating and stirring may be performed at 100 ℃.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the cleaning step is performed in a cleaning vessel, and the cleaning vessel may be made of any one of synthetic quartz, fluorine resin, silicon carbide, and silicon nitride.

In the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the drying step may be performed at a temperature of less than 300 ℃ after injecting an inert gas in a vacuum state.

In the method of manufacturing synthetic quartz powder according to an embodiment of the present invention, the sintering step may be performed by injecting dry air and inert gas together in a vacuum state.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the inert gas may be any one selected from nitrogen, helium, hydrogen, and argon, and may be an inert gas having a dew point of-40 ℃ or lower.

In the method for manufacturing synthetic quartz powder according to an embodiment of the present invention, the sintering temperature may be divided into 100 to 300 ℃, 600 to 1000 ℃, 1200 to 1300 ℃, and the porous closed pores of the dried silica gel are closed to prepare the synthetic quartz glass powder.

According to an embodiment of the present invention, the alkali silicate solution is prevented from being gelled by adjusting the concentration and temperature of silica in the alkali silicate solution, the durability of the ion exchange resin is prevented from being lowered, and the replacement cycle of the ion exchange resin is extended.

Further, according to an embodiment of the present invention, the step of heating the wet gel by the infrared heater in the inert gas state with a low partial pressure of steam to evaporate the water contained in the wet gel and then drying the wet gel in a vacuum state has an effect that energy cost can be saved compared to the freezing and thawing step.

Drawings

Fig. 1 is a flowchart showing the entire process flow of a method for manufacturing synthetic quartz powder according to an embodiment of the present invention.

Fig. 2 is a flowchart illustrating a process of preparing synthetic quartz powder from dried silica gel in a method of manufacturing synthetic quartz powder according to an embodiment of the present invention.

Detailed Description

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The method for preparing synthetic quartz powder according to an embodiment of the present invention comprises the steps of: preparing an alkali silicate solution (S100); cooling the alkali silicate solution (S200); preparing a colloidal silica sol aqueous solution (S300); performing dissociation elution and ion exchange (S400); growing the particle size of the silica (S500); preparing a wet gel (S600); removing moisture contained in the wet gel to prepare a dry silica gel (S700); a synthetic quartz powder is prepared (S800).

First, hydrophilic silica and a water-soluble alkali metal hydroxide are hydrolyzed in ultrapure water, and then stirred to prepare an alkali silicate solution having a silica concentration of 15% or more (S100).

Then, the content of metal impurities in the hydrophilic silicon dioxide is less than 1ppm, and the specific surface area range of the hydrophilic silicon dioxide is 90-300 m²(ii) Silica fume (fuse Silica) or fused Silica in an amount of/g, and hydrolyzing with an alkali metal hydroxide.

The water-soluble alkali metal oxide may be any one of sodium hydroxide, potassium hydroxide and lithium hydroxide, and hydrophilic silica is added for hydrolysis to obtain Silica (SiO)₂) And the alkali metal hydroxide and water undergo exothermic reaction to generate heat of less than 40 ℃ and dissolve.

The molar ratio of the hydrophilic silica to the water-soluble alkali metal oxide may be in the range of 1 to 4.5, and the hydrophilic silica and the water-soluble alkali metal oxide may be reacted at the above molar ratio.

After the alkali silicate solution is prepared by the above method, the alkali silicate solution is diluted by adding ultrapure water to adjust the concentration of silica to be in the range of 1 to 6.5%, and the alkali silicate solution can be prepared at a temperature in the range of 0 to 5 ℃ by performing primary cooling and secondary cooling using a cooler (giller) (S200).

Specifically, in the primary cooling, the temperature of the alkali metal silicate aqueous solution (containing silica at a concentration of 15% or more) is about 40 ℃, and the alkali metal silicate aqueous solution is diluted to a concentration of 1 to 6.5% by adding ultrapure water at 0 to 15 ℃, and the temperature of the alkali metal silicate aqueous solution is changed from 40 ℃ to 25 to 30 ℃.

That is, in the primary cooling, dilution and cooling can be simultaneously performed by adding ultrapure water to the alkali metal silicate aqueous solution.

The alkali silicate solution after the primary cooling is selected to be cooled secondarily by any one of cooling of a cooler provided in the reactor and cooling using a separate cooling unit, and the alkali silicate solution after the secondary cooling is changed to 0 to 5 ℃.

That is, the alkali silicate solution is passed through the concentration of diluted silica and cooled, thereby having an effect of preventing the viscosity of the alkali silicate solution from increasing and preventing gelation when passing through the ion exchange column.

Further, in order to prevent gelation of the alkali silicate solution, it is carried out by selecting a method of adjusting any one of the silica (silica) concentration, the pH value (pH) and the temperature, and when the adjustment is carried out by the pH value (pH), there is a disadvantage that the durability of the ion exchange resin is remarkably reduced and the ion exchange resin must be frequently replaced, so that the durability of the ion exchange resin can be ensured and gelation of silica can be prevented by controlling the silica (silica) concentration and the temperature.

An alkali silicate solution at a temperature of 0 to 5 ℃ is injected into the ion exchange column, and H + type cation exchange is performed, thereby preparing a colloidal silica sol aqueous solution (S300).

Here, when the concentration of silica is adjusted, gelation of silica (a phenomenon in which silicic acid precipitates as a gel) is promoted when the ion exchange column comes into contact with carbon dioxide contained in the air, and thus an air barrier type closed structure is formed to realize ion exchange.

Further, before the alkali silicate aqueous solution is injected into the ion exchange column, an inert gas is injected into the inside of the ion exchange column by vacuum replacement or forced air blowing, thereby preventing a gelation phenomenon at the time of preparing the colloidal silica sol aqueous solution.

The colloidal silica sol aqueous solution prepared by such a step is prepared within a range of pH 1 to 3.

The colloidal silica sol aqueous solution may be subjected to dissociation elution and ion exchange by adding the first additive and stirring the same (S400).

The first additive is any one of hydrochloric acid, nitric acid, sulfuric acid, and hydrogen peroxide, and a chemical solution of an electronic grade or more is used for high-purity synthesis of the quartz powder.

After the first additive is added to the colloidal silica sol aqueous solution, the first additive is stirred to dissociate and elute the alkali metal and the polyvalent metal ion bonded to the inside of the silicic acid polymer particle.

After the dissociation and elution, in the case of performing ion exchange, similarly to the case of preparing a colloidal silica sol aqueous solution by injecting an alkali silicate solution into an ion exchange column, an ion exchange column having an air barrier type sealing structure is used, an inert gas is injected into the ion exchange column by vacuum replacement or forced air blowing to remove air, and then the colloidal silica sol aqueous solution is ion-exchanged.

That is, in steps S300 and S400, only the solutions (the alkali silicate solution and the colloidal silica sol aqueous solution) injected into the ion exchange column are different from each other, and the method for preparing the synthetic quartz powder is the same.

The aqueous colloidal silica sol solution in which dissociation elution and ion exchange are completed may be further added with a second additive, and then stirred to grow the particle size of silica (S500).

Here, the second additive is any one of ammonia water and amine, which are chemical solutions of electronic grade or more, and the dropping rate is controlled to 1L/min so that the variation width of the pH (pH) can be minimized, thereby preventing the local gelation of the colloidal silica sol aqueous solution.

Such a second additive is added to the colloidal silica sol aqueous solution and stirred at a temperature in the range of 20 to 80 ℃, thereby enabling the particle size of the silica to grow to 10nm or more.

Thereafter, the colloidal silica sol aqueous solution may be filtered, concentrated, and added to prepare a wet gel (S600).

Specifically, the colloidal silica sol aqueous solution is filtered through a separate filtration membrane, and then concentrated, whereby the concentration of silica particles can be increased.

The filtration membrane for filtering the colloidal silica sol aqueous solution is made of a chemically resistant material, prevents elution due to acid radicals of the colloidal silica sol solution, has a pore size within a range of 10 to 15nm, and is configured to be capable of filtering only water smaller than the pore size.

The colloidal silica sol solution subjected to filtration and concentration is further added with ammonia water, and then heated by high frequency, infrared heating, and hot air, whereby wet gel can be prepared.

Here, the above-described heating structure can promote the gelation reaction by heating to less than 160 ℃, and can prevent the generation of large voids due to the rapid aggregation of colloidal silica particles, and can suppress the occurrence of bubbles in the synthetic quartz glass to be produced later.

Thereafter, the wet gel may be evaporated and dried to remove moisture contained in the wet gel, thereby preparing a dry silica gel (S700).

Specifically, there are several methods for preparing dry silica gel from wet gel as follows: preparing dry silica gel through evaporation and drying procedures; and preparing the dried silica gel through the freezing and thawing steps, wherein the step of drying in a vacuum state after evaporating the water contained in the wet gel by heating with an infrared heater in an inert gas state having a low steam partial pressure has an effect of saving energy cost compared with the freezing and thawing steps, and therefore, the water contained in the wet gel is removed through the evaporation and drying steps.

The wet gel can be prepared as a dry silica gel through such a process, and then a synthetic quartz powder can be prepared through a separate process (S800).

Specifically, the synthetic quartz powder can be produced by pulverizing dry silica gel to produce silica gel fine particles (S810), washing the produced silica gel fine particles with an acidic aqueous solution or ultra-pure water (S820), and subjecting the washed silica gel fine particles to the steps of drying (S830) and sintering (S840) in this order.

In the step of pulverizing and drying the silica gel (S810), the dried silica gel is pulverized by a pulverization structure, and the pulverization structure may be any one of a roll mill, a ball mill, a disc mill, and a jet mill.

The portion of the pulverization structure contacting the dry silica gel is made of zirconium, synthetic quartz material, thereby preventing oxidation of the pulverization structure and also having an effect of improving durability.

The pulverized dry silica gel having such a pulverization structure is pulverized into a particle size of 250 to 500 μm in consideration of volume shrinkage during sintering.

The pulverized dry silica gel pulverized in the above-described step may be washed with any one of an acidic aqueous solution and ultrapure water (S820).

The acidic aqueous solution is any one of hydrochloric acid, nitric acid and sulfuric acid of electronic grade or more, and is heated and stirred at a temperature of 100 ℃ or less to wash the pulverized product.

Here, the cleaning vessel to be cleaned is made of any one material of synthetic quartz, fluorine resin, silicon carbide, and silicon nitride, so that it is possible to prevent contamination by elution of impurities from the cleaning vessel.

After the washing (S820), the pulverized material is dried to remove water that has flowed in during the washing (S830).

Injecting inert gas into the pulverized material under vacuum, and heating the pulverized material at a temperature of less than 300 deg.C by heating mechanism such as high frequency heating, so as to prevent pores of the pulverized material of dried silica gel from being closed.

Further, classification may be performed on the pulverized material (S831).

The material of the mesh of the grain sizer used in the classification may be selected from any one of polymer plastics including nylon, fluorine resin, polypropylene, and stainless steel (SUS) coated with the above-mentioned plastics, so as to prevent inflow of moisture from the outside due to scratches caused by the dry silica gel with a strong hardness (mohs hardness of 5).

Here, in consideration of volume shrinkage at the time of sintering, it is preferable that the particle diameter of the dried silica gel subjected to classification be adjusted within a range of 250 to 500 μm.

The dried silica gel having completed the classifying, drying step may be sintered to prepare synthetic quartz powder (S840).

Specifically, the dried silica gel is sintered by injecting dry air and an inert gas under vacuum, and the inert gas having a dew point of-40 ℃ or lower is preferably used for removing silanol.

The inert gas is any one of nitrogen, helium, hydrogen, and argon, and among them, nitrogen may be nitrided, and thus it is necessary to pay attention when used at high temperature.

The sintering temperature is divided into 100-300 ℃, 600-1000 ℃ and 1200-1300 ℃ for sintering, and the porous holes of the silica gel are dried to prepare the synthetic quartz glass powder.

The above description is only an exemplary illustration of the technical idea of the present invention, and a person having a basic knowledge in the technical field to which the present invention belongs can realize various modifications and variations within a range not departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are only for illustration and not intended to limit the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments described above. The scope of the present invention should be construed based on the claims, and it should be construed that all technical ideas within the equivalent scope are included in the scope of the present invention.