KR102141829B1 - Manufacturing method of synthetic quartz powder - Google Patents

Abstract

The present invention relates to a method for producing synthetic quartz powder. The method of manufacturing a synthetic quartz powder according to an embodiment of the present invention includes the steps of preparing an aqueous alkali silicate solution, diluting and cooling the aqueous alkali silicate solution, ion-exchanging the aqueous alkali silicate solution to prepare a colloidal silica sol aqueous solution, colloidal Dissociation elution and ion exchange by adding the first additive to the silica sol aqueous solution, growing the particle diameter of the colloidal silica by adding the second additive to the colloidal silica sol aqueous solution, filtering, concentrating, and adding the colloidal silica sol aqueous solution to wet it It includes a step of preparing a gel, a step of preparing a dry silica gel by removing moisture contained in the wet gel, and a step of preparing a synthetic quartz powder by processing the dried silica gel.

Description

Manufacturing method of synthetic quartz powder

The present invention relates to a method for producing synthetic quartz powder. More specifically, the present invention relates to a method for producing synthetic quartz powder for preparing synthetic quartz glass powder through a sol-gel manufacturing method.

Recently, quartz glass products used in the optical communication field, the semiconductor industry, and the like have been very strictly managed in terms of their purity.

Such high-purity quartz glass uses a natural quartz powder (or called sand) obtained by crushing natural quartz as a raw material to produce a glass product material, and silicon tetrachloride oxyhydrochloride (散There is a method of manufacturing a material of a glass product using a vapor mass obtained by attaching and growing vapor generated by decomposition in water to a substrate.

However, the above-described method for producing synthetic quartz using the silicon tetrachloride oxyhydrogen salt can be mass-produced, but contains impurities such as fine bubbles, which has caused problems in the semiconductor industry such as photomasks and crucibles for single crystal growth. To solve the problem was to solve the problem through (Patent Document 1), it will be described in detail with reference to (Patent Document 1) as follows.

(Patent Document 1) relates to a method for producing a high-purity synthetic silica powder, according to which, a first step of reacting an aqueous alkali metal hydroxide with fumed silica to produce an alkali metal silicate salt solution, the obtained alkali metal silicate salt solution A second process of obtaining an aqueous silica solution within a range of 9 to 11 by de-alkali treatment, a third process of performing a positive ion exchange treatment of the obtained aqueous silica solution, and setting the pH of the aqueous solution to 2 to 3, the obtained silica A fourth process of concentrating and gelling the aqueous solution, a fifth process of drying the obtained gelled product, a sixth process of obtaining a pulverized product by pulverizing the dried gelate, a seventh process of treating the pulverized product with an acid aqueous solution, acid And an eighth process of firing the pulverized product treated with an aqueous solution using a dry gas at 1100 to 1300 degrees.

However, the above-mentioned (Patent Document 1) controls the pH (pH) to prevent the increase in viscosity of the ion exchange resin and the resulting gelation clogging when the silica aqueous solution passes through the ion exchange, but its effect is insufficient, and the silica aqueous solution is ionic. When the ion exchange was performed through the exchange resin, the durability of the ion exchange resin was low, and there was a problem of frequent replacement of the ion exchange resin. As the ion exchange resin was frequently replaced, the price of synthetic quartz powder powder increased. .

Japanese Patent Registration No. 6,141,710

An object of the present invention is to provide a method for producing a synthetic quartz powder for producing a synthetic quartz glass powder through a sol-gel manufacturing method.

In order to solve the above problem,

Method of manufacturing a synthetic quartz powder according to an embodiment of the present invention

(a) hydrolyzing the hydrophilic silica and water-soluble alkali metal hydroxide in ultrapure water, followed by stirring for 1 hour or more to prepare an aqueous alkali silicate solution having a concentration of silicon dioxide of at least 15%;

(b) After performing the primary cooling while diluting the concentration of silicon dioxide by diluting the alkali silicate aqueous solution with ultrapure water, using a chiller in the reactor itself or a liquid-cooled cooling using a separate chiller unit, etc. Performing secondary cooling in the range of 20 degrees, and preparing an aqueous alkali silicate solution in the range of 0 to 5 degrees;

(C) preparing a colloidal silica sol aqueous solution by injecting the cooled alkali silicate aqueous solution into an ion exchange column and performing H+ type cation exchange;

(d) adding a first additive to the colloidal silica sol aqueous solution and stirring it to dissociate and dissociate;

(e) adding a second additive to the colloidal silica sol aqueous solution and stirring it within a range of 20 to 80 degrees to grow the particle size of the colloidal silica;

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

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

(h) preparing a synthetic quartz powder by processing the dried silica gel;

It may include.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the hydrophilic silica of step (a) has a metal impurity content of less than 1 ppm and a specific surface area of 90 to 300 m2/g fume silica or Any one of fused silica can be selected.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the water-soluble alkali metal hydroxide in step (a) may be any one of sodium hydroxide, potassium hydroxide or lithium hydroxide.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the molar ratio of the hydrophilic silica and alkali metal hydroxide in step (a) is 1 to 4.5, and the hydrophilic silica and alkali metal hydroxide in the molar ratio described above. Can react.

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

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the alkali silicate aqueous solution prepared in step (b) may be prepared in a concentration of silicon dioxide (SiO2) in the range of 1 to 6.5%. .

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the ion exchange tower of step (c) is formed of an air-blocking sealed structure to absorb carbon dioxide of the alkali silicate aqueous solution to precipitate silicic acid as a gel. The phenomenon can be prevented.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the ion exchange tower of step (c) is replaced with an inert gas by vacuum displacement or pressurized blowing before injecting the alkali silicate aqueous solution. Air inside can be removed.

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

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, step (d) may dissociate and elute alkali metals and polyvalent metal ions bound inside polymer particles of silicic acid.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the second additive in step (e) may be added by selecting either ammonia water or amine.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the second additive can prevent the local gelation of the colloidal silica by managing the dropping rate to less than 1 L per minute using a chemical solution of an electronic grade or higher. have.

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

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the filtration membrane of step (f) is provided with a pore size of 10 to 15 nm, and may be made of a chemical resistant material.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the ammonia water of step (f) may use a chemical solution of an electronic grade or higher, and a dripping rate may be produced at less than 1 L per minute.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, after the step (f) is added to the ammonia water, it is possible to prepare a wet gel through high-frequency, infrared heating, hot air heating.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the high frequency, infrared heating, and hot air heating may be heated to less than 160 degrees to produce a wet gel.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, step (g) is heating the wet gel with an infrared heater in an inert gas having a low partial pressure of water vapor to remove moisture contained in the wet gel. It can be evaporated and dried in vacuo.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, step (h) is

(h)-1. Crushing the dried silica gel to produce fine particles of silica gel;

(h)-2. Washing the fine particles of the silica gel with either an aqueous acid solution or ultrapure water;

(h)-3. Drying the washed silica gel;

(h)-4. Calcining the dried silica gel;

It may further include.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the crushing is pulverized through a crushing means, and the crushing means is selected from any one of a roll mill, a ball mill, a disc mill, and a jet mill to dry the The silica gel is crushed, and may be made of a material of zirconium or synthetic quartz.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the acid aqueous solution is used by selecting one of hydrochloric acid or nitric acid sulfuric acid or higher, and simultaneously heating and stirring at a temperature of 100 degrees or less. can do.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the cleaning is performed in a cleaning container, and the cleaning container may be any one of synthetic quartz, fluorine resin, carbon carbide, and silicon nitride. have.

In the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the drying may be dried within a temperature of less than 300 degrees after injecting an inert gas in a vacuum.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the firing may be injected with dry air and an inert gas together in a vacuum.

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the inert gas is used by selecting any one of nitrogen, helium, hydrogen, and argon, a gas having a dew point of -40 degrees or less can be used. .

In addition, in the method of manufacturing a synthetic quartz powder according to an embodiment of the present invention, the firing temperature is divided into sections of 100 to 300 degrees, 600 to 1000 degrees, 1200 to 1300 degrees, and the porous of the dried silica gel is Synthetic quartz powder can be produced by closing.

These solutions will become more apparent from the following detailed description of the invention based on the accompanying drawings.

Prior to this, the terms or words used in the specification and claims should not be interpreted in a conventional and lexical sense, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. Based on the principle of being able to be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

According to an embodiment of the present invention, by controlling the concentration and temperature of the silicon dioxide aqueous solution of silicon silicate to prevent the gelation of the alkali silicate aqueous solution, to prevent the durability of the ion exchange resin is lowered, the replacement cycle of the ion exchange resin It has the effect of increasing.

In addition, according to an embodiment of the present invention, after heating the infrared heater in an inert gas having a low partial pressure of water vapor to evaporate moisture contained in the wet gel, drying in a vacuum state has an effect of reducing energy costs than freezing and thawing processes. have.

1 is a flow chart showing the overall process sequence of a method of manufacturing a synthetic quartz powder according to an embodiment of the present invention.
Figure 2 is a flow chart showing a process for producing a synthetic quartz powder in a dry silica gel of a method for producing a synthetic quartz powder according to an embodiment of the present invention.

The specific aspects and specific technical features of the present invention will become more apparent from the following specific contents and embodiments associated with the accompanying drawings. It should be noted that in this specification, when adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing an embodiment of the present invention, when it is determined that detailed descriptions of related known configurations or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected to or connected to the other component, but another component between each component It should be understood that elements may be "connected", "coupled" or "connected".

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

The method for preparing a synthetic quartz powder according to an embodiment of the present invention includes the steps of preparing an aqueous alkali silicate solution (S100), cooling the aqueous alkali silicate solution (S200), and preparing a colloidal silica sol aqueous solution (S300). Wow, dissociation elution and ion exchange (S400), growing silica particle diameter (S500), and preparing a wet gel (S600), and removing moisture contained in the wet gel to prepare a dry silica gel It includes a step (S700) and the step of preparing a synthetic quartz powder (S800).

First, after hydrolysis of hydrophilic silica and water-soluble alkali metal hydroxide in ultrapure water, the mixture is stirred to prepare an alkali silicate alkali solution containing at least 15% by weight of silicon dioxide (S100).

Here, the hydrophilic silica can be hydrolyzed with an alkali metal hydroxide by selecting any one of fume silica or fused silica having a metal impurity content of less than 1 ppm and a specific surface area of 90 to 300 m 2 /g.

The water-soluble alkali metal oxide may be any of sodium hydroxide, potassium hydroxide or lithium hydroxide, and hydrolysis is performed by adding hydrophilic chelica so that the concentration of silicon dioxide (SiO2) is 15% by weight or more. Dissolution reacts with heat of less than 40 degrees due to the exothermic reaction of water.

In addition, the molar ratio of the hydrophilic silica and the water-soluble alkali metal oxide is in the range of 1 to 4.5, and the hydrophilic silica and the water-soluble alkali metal oxide can be reacted at the molar ratio described above.

After preparing the alkali silicate aqueous solution in the above-described manner, the primary cooling is performed while diluting the alkali silicate aqueous solution by adding ultrapure water to adjust the concentration of silicon dioxide within the range of 1 to 6.5% by weight, and using chiller to secondary By performing cooling, an aqueous alkali silicate solution in a range of 0 to 5 degrees may be prepared (S200).

Specifically, the primary cooling consists of an alkali silicate aqueous solution (containing at least 15% by weight of silicon dioxide) at around 40 degrees, and by adding ultrapure water at 0 to 15 degrees, silicon dioxide is added at a concentration of 1 to 6.5% by weight. As the dilution is made, the temperature of the aqueous alkali silicate is made from 25 to 30 degrees at 40 degrees.

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

After completing the primary cooling, the aqueous silicate alkali solution is cooled through a chiller provided in the reactor, or a secondary cooling is performed by selecting any one of liquid-cooled cooling using a separate chiller unit. The alkali silicate aqueous solution after being carried out has a temperature of 0 to 5 degrees.

That is, the alkali silicate aqueous solution has an effect of preventing and increasing the viscosity of the alkali silicate aqueous solution and preventing gelation when passing through the ion exchange column by diluting and cooling the concentration of silicon dioxide.

In addition, the alkali silicate aqueous solution is selected by any one of the methods of controlling the concentration, silicon dioxide (pH), and temperature of silicon dioxide (silica) in order to prevent gelation. When the pH is adjusted to pH, the ion exchange resin The durability is significantly lowered, and there is a disadvantage that the ion exchange resin must be frequently replaced. The method of controlling the concentration and temperature of silicon dioxide (silica) is used to ensure the durability of the ion exchange resin and prevent silica from gelling. can do.

The aqueous solution of alkali silicate in the range of 0 to 5 degrees may be injected into an ion exchange column, and H+ type positive ion exchange may be performed to prepare a colloidal silica sol aqueous solution (S300).

Here, the ion exchange tower promotes the gelation of silica (a phenomenon in which silicic acid precipitates as a gel) when it comes into contact with carbon dioxide contained in the air when adjusting the concentration of silicon dioxide, and thus ion exchange is achieved by an air-tight sealing structure.

In addition, the alkali silicate aqueous solution prevents gelation when preparing the colloidal sol silica aqueous solution by removing the air inside the exchange column by injecting the inside of the exchange column with a vacuum displacement or pressurized blown air before injecting it into the ion exchange column. can do.

The colloidal silica sol aqueous solution prepared by this process is prepared in the range of 1 to 3 peha (pH).

The colloidal silica sol aqueous solution can dissociate and dissociate and ion exchange by adding a first additive and stirring it (S400).

The first additive is any one of hydrochloric acid, nitric acid, sulfuric acid, and hydrogen peroxide, and an electronic grade or higher chemical liquid is used for high purity of the powder of synthetic quartz.

After adding the first additive to the colloidal silica sol aqueous solution, it is stirred to dissociate and elute alkali metal and polyvalent metal ions bound inside the polymer particles of silicic acid.

After dissociation and dissolution, when performing ion exchange, an ion exchange column with an air-tight closed structure is used, and an inert gas is vacuumed in the same manner as when preparing a colloidal sol silica aqueous solution by injecting an aqueous alkali silicate solution into the ion exchange column. After removing the air by injecting it into the inside of the ion exchange column with a replacement or pressurized blowing, ion-exchange the colloidal silica sol aqueous solution.

That is, the ion exchange towers carried out in S300 and S400 are different from each other only in the injected solution (aqueous alkali silicate solution and colloidal silica sol aqueous solution), and the method of manufacturing is the same.

The colloidal silica sol aqueous solution in which dissociation elution and ion exchange is completed may be further stirred by adding a second additive to grow the particle size of the silica (S500).

Here, the second additive is either an ammonia water or an amine in a chemical solution of an electronic grade or higher, and it is possible to prevent local gelation of the colloidal silica sol aqueous solution by controlling the dropping speed at 1 L per minute in order to minimize the change in pH (pH).

The second additive may be added to the colloidal silica sol aqueous solution and stirred at a temperature in the range of 20 to 80 degrees to grow the particle size of silica to 10 nm or more.

Subsequently, the colloidal silica sol aqueous solution may be prepared through wet filtration through filtration, concentration, and addition (S600).

Specifically, after the colloidal silica sol aqueous solution is filtered through a separate filter membrane, the colloidal silica sol aqueous solution can be concentrated to increase the concentration of silica particles.

In addition, the filtration membrane for filtering the colloidal silica sol aqueous solution is made of a chemical-resistant material to prevent elution due to the acidity of the colloidal silica sol aqueous solution, and the pore size is in the range of 10 to 15 nm to filter only moisture below the corresponding pore size. It is configured to be able to.

The colloidal silica sol aqueous solution subjected to filtration and concentration can be further added with ammonia water afterwards, and a wet gel can be prepared through high frequency, infrared heating, and hot air heating.

Here, the above-mentioned heating means can promote the gelation reaction by heating to less than 160 degrees, prevent the formation of large voids due to rapid agglomeration of colloidal silica particles, and can suppress the generation of bubbles in the synthetic quartz glass to be produced later. .

Thereafter, the wet gel may remove moisture contained in the wet gel through evaporation and drying to prepare a dry silica gel (S700).

Specifically, there are methods for preparing dry silica gel from wet gels, e.g., evaporation and drying processes, to prepare dry silica gels, and to freeze and thaw processes, to prepare dry silica gels, and inert gas with low partial pressure of water vapor. After heating the infrared heater heating to evaporate the moisture contained in the wet gel, the process of drying in a vacuum state has an effect of reducing the energy cost than the freezing and thawing process. In the present invention, the wet gel through the evaporation and drying process Removes moisture contained in.

In this process, the wet gel can be made of dry silica gel, and then a synthetic quartz powder can be produced through a separate process (S800).

Specifically, the dried silica gel is pulverized to produce fine particles of silica gel (S810), and the fine particles of silica gel are washed with an aqueous solution and ultrapure water (S820), and the fine particles of the cleaned silica gel are dried (S830) and fired (S840). Synthetic quartz powder can be produced by processing in order.

The step of crushing the dried silica gel (S810) pulverizes the dried silica gel through a grinding means, and the grinding means may be configured by selecting any one of a roll mill, a ball mill, a disc mill, and a jet mill.

The crushing means is made of a material made of zirconium and synthetic quartz in contact with the dry silica gel, thereby preventing oxidation of the crushing means and improving durability.

The pulverized product of the dried silica gel pulverized through the pulverizing means is pulverized to a particle diameter in the range of 250 to 500 um in consideration of volume shrinkage during firing.

The pulverized product of the dried silica gel pulverized by the above-described process can be washed by selecting either an aqueous acid solution or ultrapure water (S820).

The acid aqueous solution is any one of hydrochloric acid, nitric acid, and sulfuric acid of an electronic grade or higher, and simultaneously heated and stirred at a temperature of 100 degrees or less to wash the ground.

Here, the cleaning container for cleaning is made of a material of any one of synthetic quartz, fluorine resin, silicon carbide, and silicon nitride to prevent contamination of the elution of impurities from the cleaning container.

After the washing (S820) is completed, the pulverized product is dried to remove the moisture introduced while washing (S830).

The pulverized material is heated in a temperature range of less than 300 degrees by heating means such as high-frequency heating by injecting an inert gas in a vacuum to prevent pores of the pulverized dry silica gel from being closed.

In addition, the pulverized material may be classified (S831).

The material of the mesh of the particle size separator used for classification is selected from polymer plastics including nylon, fluororesin, and polypropylene, and stainless steel (SUS) coated with the plastic materials described above. It is possible to prevent impurities from being introduced from the outside due to the scratch by 5).

Here, it is preferable that the particle size of the dried silica gel, which has been classified, is manufactured within a range of 250 to 500 um in consideration of volume shrinkage during firing.

The dried silica gel, which has been classified and dried, can be calcined to produce synthetic quartz powder (S840).

Specifically, the dried silica gel is fired by injecting dry air and an inert gas in a vacuum, and it is preferable to use an inert gas having a dew point of -40 or less to remove the silanol group.

Further, the inert gas is any one of nitrogen, helium, hydrogen, and argon, and among these, nitrogen has the possibility of nitridation, so care must be taken when using at high temperatures.

The firing temperature is divided into sections of 100 to 300 degrees, 600 to 1000 degrees, 1200 degrees to 1300 degrees to perform silanol groups, internal silanol groups, and isolated silanol groups due to surface adsorption water. Closed to prepare a powder of synthetic quartz glass.

The present invention has been described in detail through one embodiment, but this is for specifically describing the present invention, and * according to the present invention is not limited thereto. In addition, the terms "include", "consist", or "have" as described above mean that the corresponding component can be inherent unless specifically stated to the contrary, excluding other components However, it should be interpreted as being able to further include other components, and all terms, including technical or scientific terms, are generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined. It has the same meaning as being.

In addition, the above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains can variously modify and modify the scope without departing from the essential characteristics of the present invention. Therefore, the exemplary embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain the scope, and the scope of the technical spirit of the present invention is not limited by the exemplary embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

Claims (26)

(a) hydrolyzing the hydrophilic silica and water-soluble alkali metal hydroxide in ultrapure water, followed by stirring for 1 hour or more to prepare an aqueous alkali silicate solution having a concentration of silicon dioxide of 15% by weight or more;
(b) After diluting the alkali silicate aqueous solution with ultrapure water and performing primary cooling while diluting the concentration of silicon dioxide, either cooling in the reactor itself using a chiller or liquid cooling using a separate chiller unit is used. Performing secondary cooling and preparing an aqueous alkali silicate solution in the range of 0 to 5 degrees;
(C) preparing a colloidal silica sol aqueous solution by injecting the cooled alkali silicate aqueous solution into an ion exchange column and performing H+ type cation exchange;
(d) adding a first additive to the colloidal silica sol aqueous solution and stirring it to dissociate and dissociate;
(e) adding a second additive to the colloidal silica sol aqueous solution and stirring it within a range of 20 to 80 degrees to grow the particle size of the colloidal silica;
(f) using a colloidal silica sol aqueous solution on the filtration membrane to concentrate it, and adding ammonia water to prepare a wet gel;
(g) After heating the wet gel with an infrared heater in an inert gas having a low partial pressure of water vapor to evaporate the moisture contained in the wet gel, drying in a vacuum to remove moisture contained in the wet gel, and drying silica gel. Manufacturing;
(h) preparing a synthetic quartz powder by processing the dried silica gel;
Method for producing a synthetic quartz powder comprising a.
The method according to claim 1,
The hydrophilic silica of the step (a) is a method of producing a synthetic quartz powder of any one of fume silica or fused silica having a metal impurity content of less than 1 ppm and a specific surface area of 90 to 300 m2/g.
The method according to claim 1,
The method of preparing a synthetic quartz powder in which the water-soluble alkali metal hydroxide in step (a) is any one of sodium hydroxide, potassium hydroxide or lithium hydroxide.
The method according to claim 1,
The molar ratio of the hydrophilic silica and alkali metal hydroxide in the step (a) is 1 to 4.5, and the method for producing a synthetic quartz powder for reacting the hydrophilic silica and alkali metal hydroxide with the molar ratio described above.
The method according to claim 1,
The step (b) is a method of manufacturing a synthetic quartz powder having an ultrapure water temperature of 0 to 15 degrees.
The method according to claim 1,
The method of preparing a synthetic quartz powder in which the concentration of silicon dioxide (SiO2) is 1 to 6.5% by weight in the aqueous alkali silicate solution prepared in step (b).
The method according to claim 1,
The ion exchange tower of the step (c) is made of an air-blocking sealed structure, and absorbs carbon dioxide of the alkali silicate aqueous solution to prevent the precipitation of silicic acid into a gel.
The method according to claim 1,
The ion exchange tower of the step (c) is a method of manufacturing a synthetic quartz powder to remove the air in the interior of the exchange column by injecting a vacuum replacement or pressurized blowing of an inert gas before injecting the alkali silicate aqueous solution.
The method according to claim 1,
The first additive of the step (d) is a method of producing a synthetic quartz powder which is any one of hydrochloric acid, nitric acid, sulfuric acid and hydrogen peroxide.
The method according to claim 1,
The step (d) is a method for producing a synthetic quartz powder that dissociates and elutes alkali metal and polyvalent metal ions bound inside polymer particles of silicic acid.
The method according to claim 1,
The second additive of the step (e) is a method of producing a synthetic quartz powder which is either ammonia water or amine.
The method according to claim 1,
The second additive is a method of manufacturing a synthetic quartz powder to prevent the local gelation of the colloidal silica by controlling the dropping speed to less than 1 L per minute using a chemical liquid of an electronic grade or higher.
The method according to claim 1,
Method of manufacturing a synthetic quartz powder to grow the particle size of the colloidal silica to 10nm or more in the step (e).
The method according to claim 1,
The (f) step of the filtration membrane is provided with a pore size of 10 to 15 nm, a method of manufacturing a synthetic quartz powder made of a chemical-resistant material.
The method according to claim 1,
The method of manufacturing a synthetic quartz powder in which the ammonia water of step (f) uses an electronic grade or higher chemical liquid and a dripping speed is less than 1 L per minute.
The method according to claim 1,
In the step (f), after adding the ammonia water, a method for preparing a synthetic quartz powder for producing a wet gel through high-frequency, infrared heating, and hot air heating.
The method according to claim 16,
The high-frequency, infrared heating, hot air heating method of producing a synthetic quartz powder to produce a wet gel by heating to less than 160 degrees.
delete The method according to claim 1,
Step (h) is
(h)-1. Crushing the dried silica gel to produce fine particles of silica gel;
(h)-2. Washing the fine particles of the silica gel with either an aqueous acid solution or ultrapure water;
(h)-3. Drying the washed silica gel;
(h)-4. Calcining the dried silica gel;
Method of manufacturing a synthetic quartz powder further comprising.
The method according to claim 19,
The crushing is crushed through a crushing means,
The crushing means is a method of manufacturing a synthetic quartz powder consisting of a material of a zirconium or synthetic quartz, crushing the dried silica gel by selecting any one of a roll mill, a ball mill, a disc mill, and a jet mill.
The method according to claim 19,
The acid aqueous solution is any one of hydrochloric acid and nitric acid sulfuric acid or higher, and the method for producing a synthetic quartz powder heated and stirred at a temperature of 100 degrees or less.
The method according to claim 19,
The cleaning is done in a cleaning container,
The material of the cleaning container is a method of manufacturing synthetic quartz powder, which is any one of synthetic quartz, fluorine resin, silicon carbide, and silicon nitride.
The method according to claim 19,
The drying is a method of manufacturing a synthetic quartz powder that is dried within a temperature of less than 300 degrees after injecting an inert gas in a vacuum.
The method according to claim 19,
The firing method of the synthetic quartz powder to inject dry air and inert gas together in a vacuum.
The method of claim 23 or 24,
The inert gas is a method of producing a synthetic quartz powder of any one of nitrogen, helium, hydrogen, and argon with a dew point of -40 degrees or less.
The method according to claim 19,
The firing temperature is divided into 100 to 300 degrees, 600 to 1000 degrees, 1200 to 1300 degrees, and is performed by dividing the pores of the dried silica gel to produce synthetic quartz powder.

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