JPS58176136A - Preparation of quartz glass powder - Google Patents

Abstract

PURPOSE:To obtain high-purity quartz glass powder in high yield, by adding water and an alcohol to a silicate to give a solution, dispersing or suspending the solution in a liquid having no compatibility with it to form powdery or granular gel, then calcining it. CONSTITUTION:100-300pts.vol. water and 0.25pts.vol. alcohol are added to 100pts.vol. silicate. The raw material solution is dispersed or suspended in a liquid such as hexane, xylene, etc., substantially having no compatibility with the raw material solution. Powdery or granular gel formed by the treatment is separated from the mother liquor, washed, dried, and calcined. By this method, high-purity quartz glass powder useful as a main raw material for optical fiber of multicomponent system is obtained in high yield without producing dust.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing quartz glass powder with high yield and high purity without generating dust.

IMffiK is a multi-component optical fiber.

Quartz glass powder is mixed with glass-forming materials such as boron oxide and soda carbonate, and the mixture is heated in a bath to form a borosilicate glass stopper, which is gradually flattened from the bottom hole of the so-called four-sided acupuncture point. A glass fiber with a double composition is pulled out coaxially so that the glass with the composition to be measured is located on the central axis (core) K of the optical diffraction table, and stretched to form an optical fiber. If impurities are included, this will cause optical loss, so a raw material with a high N degree is used. On the other hand, silicon
Silica glass crucibles for pulling semi-quadramid single crystals such as potassium arsenide have been manufactured by molding natural ice lIi + powder into a crucible shape and heating it to semi-crystalize it, but natural crystal contains various impurities. As a result, the demand for high-quality single crystals increases, and high #B quality crucibles are desired and are often counterfeited.

Furthermore, by using hot pressing method from 1 quartz glass powder,
Q! - A method for forming a quartz glass molded body without molding is also being developed, and a quartz glass plate as a photomask substrate for pattern transfer of large scale horizontal IgJ, etc.
Although quartz glass powder is considered to be promising as a raw material for producing optical materials, the quartz glass powder according to the present invention has high OT ability to be used for these purposes as well.

Note that the silica glass powder produced according to the present invention can be obtained with i1m purity by using ethyl silicate, which is easily manufactured by Klf by Keiho Misaki, as a raw material, but especially when the raw material WI
It is clear that quartz glass powder can be obtained without any manufacturing, and since the raw material silicate ester is fermented from silicon tetrachloride, which is produced in large quantities in the semiconductor industry, it is possible to obtain quartz glass powder from natural ice islands, which are limited resources. It is also useful as an alternative raw material for general-purpose quartz glass.

Conventional quartz glass powder is t-pulverized natural quartz, which is used to manufacture crucibles for pulling silicon single crystals, but natural quartz originally contains impurities such as heavy metals. Come on! ! & Because the contamination is further removed during the crushing process.

As mentioned above, natural quartz is unsuitable for the purpose of achieving high purity 1*.

On the other hand, as a method for manufacturing quartz glass powder with a high #1 degree, for example, an oxyhydrogen flame is used. It is also possible to crush the high #1 synthetic glass mass produced by high-temperature oxidation of silicon chloride, but due to the contamination that accompanies the crushing, it is difficult to maintain purity, and the imitation that inevitably occurs due to crushing is considered. The powder is scattered as dust during crushing and handling, causing a problem with *m* raw raw noodles.

As a method for producing high-purity quartz glass powder without requiring a grinding process involving a large number of gaps, the author of the present invention proposes a method for producing quartz glass powder by clouding it with ethyl silicate.

A method for producing powdery gel and firing this powdery gel Yttp! IF has been filed (hereinafter referred to as "prior application"), but this method has a yield of 80 cm, and one point is that the main raw material, ethyl silicate, is recovered at t4.

The inventors of the present invention have conducted various studies to provide a method for increasing the yield of quartz glass powder by improving the original @ii.
Focusing on the fact that a raw material solution with a uniform composition consisting of 0.0 to 300 volumes of water is substantially miscible with many liquids such as organic solvents, the scissors raw material solution was substantially mixed with the cough raw material solution. When the raw material solution is added to an incompatible liquid so that the volume of the raw material solution is not larger than the volume of the liquid and stirred vigorously, the cough raw material bath liquid becomes fine droplets in the scissors liquid that acts as a dispersion medium and is separated. , and found that when this foreshadowing is maintained, a gel of the granular material is generated.1 The present invention Kffij! did.

That is, the gist of the present invention is to prepare a raw material solution tt prepared by adding 100 to 300 volumes of water to 100 volumes of the silicate ester, and the raw material #I? By dispersing or suspending a substance substantially miscible with K in a liquid, a powder-like gel is produced.

The present invention provides a method for producing quartz glass powder, which comprises separating and firing the granular powder.

In the present invention, a mixture of water and an alcohol not exceeding 0.25 times the volume of water can be added to the silicate ester to prepare the raw material solution4 instead of the water alone. The use of this alcohol has the effect of speeding up the preparation of the raw material solution, compared to the case where the silicate ester and water dissolve only in water, which would require a long time to prepare the raw material solution. be.

Next, each step of the present invention will be explained in detail.

tl) Preparation process of raw material solution 100 to 300 volumes of water per 100 volumes of the silicate ester are blended to dissolve the raw material solution. In this case, if the amount of water mixed per 100 volumes of broken acid ester is less than 100, the compatibility of the raw material S liquid with many liquids will increase, resulting in a decrease in yield, and the If the blending amount exceeds aoot, the resulting powdery gel will be soft and easily coagulate with each other, making it difficult to obtain it as a powder. In this process, when mixing t-silicate ester, a mixture of water and alcohol not exceeding 0.25 times the volume of water, instead of using water alone, the raw material solution should be prepared as described above. The amount of alcohol that is promoted is 0.2 of that of water.
If the volume exceeds 5 times, the compatibility with many liquids (dispersion media) increases, resulting in a decrease in yield.

In addition, it is effective to add acid or alkali to promote gelation in the next step, and although measures must be taken to prevent equipment corrosion, waste liquid, and exhaust gas, 4#l! , nitric acid, sulfur @
137 acid, formic acid, oxalic acid, acetic acid, ammonia, etc. can also be used.

(2) Production process of powdery gel The raw material solution prepared above is thoroughly stirred after a liquid (dispersion 1111t) Km that is substantially incompatible with the cough raw material solution,
The raw material solution becomes a single droplet and is dispersed in the liquid to form a suspended state.

As long as the liquid is not substantially compatible with the TFI raw material S liquid, it is not limited to %, but from one point of G2 serving of 11 items, ml! It is preferable that it is easy to obtain a high 1aK product.
On the other hand, a material with a low viscosity (with a specific gravity close to the specific gravity of the raw material solution (approximately 1) K) makes it easier to maintain the cough raw material solution fI!4 in a sufficiently dispersed state in the chain liquid. , and can be said to be advantageous.

Furthermore, #1 as a liquid! After a gel is generated by hydrolysis of J-ester, the remaining mother liquor contains alcohol, which is a by-product from the hydrolysis of the silicate ester. It is preferable to use an alcohol that can easily separate the successor alcohol, and it is advantageous to use an alcohol that has as large a difference in boiling point as possible from the alcohol because it can be separated by distillation. In addition, it goes without saying that highly toxic substances and substances with low boiling points that are difficult to handle should be avoided. Specific examples of the liquid include the following liquid compounds, but the liquid is not limited to these soups.

la) Aliphatic or aromatic substances such as hexano, xylene, etc.
Expanding hydrogen.

lbJ Higher alcohols such as hexanol and octatool.

LC) Ethers such as diethyl ether and anisole.

(dl Volume of halogenated hydrocarbons such as barchlorethylene and fluorobenzene.

le) Carbonyl such as methylisobutylated ketono, cyclohexanone, etc.

(f) Ester such as butyl phosphate.

It is preferable that the amount of 4N violet in the transfer body is equal to or more than the same amount as the raw material solution.If the amount of the 4N violet is less than the density of the raw material solution, droplets of the 4N violet solution may be dispersed in the liquid. On the contrary, the Ili[f14 in the scissors liquid became dispersed in the liquid solution, and no powdery gel was formed.

There are no limitations on the method of stirring the combination of the cough raw material Sa and the cough liquid, and an impeller-type rotary stirrer, a floater for floatation polymerization, etc. can be used.

at room temperature or while heating to speed up gel formation.
Summarizing the stirring of the mixture of the raw material #1 liquid and the axillary liquid, 1 is obtained.
The dispersed droplets of the raw material solution gel.

A powdery gel is produced. The time required to produce the powdery gel depends on the composition of the cough material solution, I
Although it depends on the temperature during agitation during mixing, it can also be determined by observing the properties of the droplets of the raw material solution.

(3) Separation of powdery gel 1. Separate the resulting powdery gel from the mother liquor by decantation or the like. It is preferable from the viewpoint of safe operation of the post-filtering process that the cough liquid and the alcohol t-powder-like gel removed from the silicate ester be sufficiently removed.

An alcohol followed by water wash is preferred.

(4) Drying the granular gel.Turn over the separated #granular gel. This drying is an indispensable step, but it is effective for reducing the contribution of the primary process because the powdery gel shrinks due to drying and the bulk increases significantly. Although it is not limited to the dry temperature of 1 degree and 1 degree, a large amount of water is removed by 250 degrees Celsius.

(5) Firing process of powdery gel The dried & granular gel 'i 1 is formed at a temperature around 1,000°C and vitrified. The firing time depends on the temperature, but is approximately 0.5 to 2 hours, and can be determined with reference to Examples.

Although the heating rate is not limited to certain times, heating a powdery gel that is insufficiently dried at a high rate will cause rapid volatilization of the water contained therein (
Therefore, cracks and tension occur in the particles of the powdery gel, resulting in S-shape 1.
Since the particle size changes, low speed external m is required depending on the need.
A multi-component glass optical transmission line is provided, which provides a method for producing quartz glass powder that enables the production of high-purity quartz glass powder at a high yield and enables the development of quartz glass powder.

It is extremely useful in manufacturing crucibles for pulling semiconductor crystals, etc.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Example 1 Methyl silicate 150ILl and 4d manufactured by Allilff
1 g of a mixed bath solution consisting of 50 d of water] was put into a Teflon hexafluoride beaker made of 7 chlorohexane 400- and 4 KIJ, and stirred vigorously with a Teflon-coated impeller-type stirring cage to completely remove the entire liquid. The flame hole was uniformly in a white S-layer state. The operation was performed at room temperature.

After about 4 hours, the whiteness of the nuclear layer suspension increased, so the stirring was continued for another 30 minutes, and when no change in whiteness was detected, the stirring was stopped and the resulting powdery gel was removed from the mother liquor. It was separated by decantation, washed four times with 50 m of distilled methanol each time, and then three times with 50 iu of distilled water, and then dried in an open electric furnace at 90°C for 7 l'204.

After drying, the powdery gel was heated in an electric furnace at a rate of 100°C for 4 hours, and then baked at 050°C for 2 hours.
．． 9? The specific gravity of this fired product is 2.20.
1, and it was confirmed that it was quartz glass. In addition, emission spectroscopic analysis revealed no impurities in the cough scorch material, and it was confirmed that +11i purity was involved. In addition,
The particles of the obtained powder had a spherical shape with a diameter of 30 to 60 μm. The yield of 56.9f corresponds to a yield of 93 Rumor.

Practical example 2 30 d of silicic acid ether prepared in 4 parts, 1 ml of ethanol produced by distillation of 90-1 drifted water, and reconsolidated from distilled water 4! ? 111
11 Shutetsu 0.5? Threaten a mixed solution consisting of.

Pour a Teflon tetrafluoride Erlenmeyer flask (capacity 300 m) into a container with 125 d of xylene.
A denser (MmRtl tube) was attached, and the mixture was heated to 65°C and stirred vigorously for 1.5 hours using a mug stirrer coated with Teflon tetrafluoride. The resulting powdery gel was separated from the mother liquor by decantation, washed four times with 30M each of distilled N ethanol, and twice with distilled water 40+WJ, and then heated at 80°C in an electric open chamber.
for 15 hours and at 250°C for 15 hours. In Sumi,
The dried granular gel was heated in an electric furnace at 200'C/hour for 1.
4mL of 100'CK was fired for 1 hour to obtain 7.9t of fired product 1. The ratio l[ of this fired product is 2.20, which is 1 quartz glass.

The yield is 98%. 1M rice subjected to emission spectroscopic analysis.

No impurity* was shipped, and it was confirmed that the product was of high purity.

Practical Example 3 20 d of distilled +11111 (normal) propyl silicate, 50 d of distilled water, 10 methanol and 0. Prepare a mixture consisting of 0.1 d of IN ammonia water, and place it in a flask (capacity 300 m) containing Teflon hexafluoride with 120 M of isooctane prepared by steaming, and tetrachloroethylene 40317 prepared by distillation in a 3-liter flask (capacity 300 m) at room temperature. The mixture was stirred vigorously for 2 hours using a stainless steel stirrer.

The resulting powdery gel was separated from the mother liquor by decanting, washed 4 times with 30 ml of ethanol and then twice with 30 111 ml of water, and then heated in an electric oven for 8 ml.
It was dried at 0°C for 15 hours and at 150°C for 8 hours. Dry cough powder granular gel was heated in an electric furnace at a rate of 100°C per qq and heated to 1,200°C for 30 minutes to form a threshold at 3.6 fP.
The specific gravity of the corn nemes + Wj obtained in @Narikiri 1 was 2.20, and 10 impurities were not detected by emission spectroscopic analysis, and the fired product was confirmed to be of high purity (it was confirmed that it was quartz glass powder). I was caught.

A yield of +5° (1i3.6) corresponds to a yield of 97.

Examples 4 to 12 A mixed solution consisting of 100 aj of methyl silicate and 100 au of methyl silicate and 41
Put a mixture of Ia solution made from a reasonable amount of steam water and various amounts of methanol into a stainless steel beaker (capacity IJ), and cover it with aluminum foil, along with the various fractions shown in Table 1. , 40° CKI) I;
．． Stir vigorously for 5 hours. The produced gel was subjected to the same treatment as in Example 2, and quartz glass powder with a -C specific gravity of 2.20 could be obtained at the yield shown in Table 1.

Table 1 Comparison Gani ~ 4, a mixture consisting of 10011j of methyl borate and 100d of methyl borate and the volume of water shown in Table 2. A mixed bath consisting of methanol/fLf:, Wrinkled Dodeca 7 also shown in Table 2
The mixture was placed in a stainless steel beaker (capacity 1) and treated in the same manner as in Examples 3 to 12.

As shown in Table 2 of Results Vi, when the amount of distilled water added is less than 100 volumes per 100 volumes of methyl silicate, and when the amount of methanol added exceeds 0.25 times the amount of distilled water, powder Although granular gel is produced and silica glass powder can be obtained by firing, the yield is extremely low, making it impractical, and if the amount of unsealed water exceeds 300 dl per 100 volumes of methyl silicate, Coarse lumps, which are considered to be aggregates of powdery gel, began to form, and quartz glass powder could not be obtained without crushing.

Table 2

Claims (1)

[Claims] (1) A raw material solution prepared by adding 100 to 300 volumes of water per 100 volumes of the Ml sapon ester to a silicate ester is poured into a liquid that is substantially incompatible with the raw material solution. distributed,
#I! A method for producing quartz glass powder, characterized in that a powder-like gel is produced by IHa, and the powder-like gel is separated and turbidized. (2) Raw material mgt obtained by adding 100 to 300 volumes of water and alcohol not exceeding 0.25 times the volume of wrinkles water to silicate ester, and the raw material solution and substantial TCSE property. Dispersed in liquid without water, W4/l
ll to produce a powdery gel. A method for producing quartz glass powder, characterized in that the granular gel is separated and formed.