JPS58190831A - Manufacture of quartz glass powder - Google Patents

Abstract

PURPOSE:To efficiently manufacture high-purity quartz glass powder without requiring a pulverizing stage, by forming fine-grained gel from ethyl silicate or the like in the presence of boric acid as a catalyst and by separating and calcining the gel. CONSTITUTION:To ethyl silicate (or propyl silicate) is added about 4-6mol water contg. boric acid so that boric acid is contained by about 1-300mmol per 1mol ethyl silicate. The molar ratio of ethyl silicate: boric acid: water is about 1: (0.001-0.3):(4-6). They are held in a suspended state by vigorous agitation to form powdered gel. The gel is separated from the mother liquor contg. by- product alcohol, washed, dried, and calcined at about 1,000 deg.C to obtain quartz glass powder.

Description

[Detailed description of the invention]

The present invention uses raw materials that are less dangerous in terms of resources. The pulverization process of quartz glass powder with a purity of rL + %, which is necessary as a raw material powder for the production of multi-component Ogtail fibers, photomask substrates for integrated circuit pattern transfer, and as a light source for sealing materials for semiconductor devices This is a method for producing quartz glass powder that requires no capital and has a higher yield.The method for producing quartz glass powder is achieved by Kuraguchi Noh. Conventionally, quartz glass powder is produced using natural crystal whole ball mills, such as Brazilian raw stone. However, in recent years, three methods have emerged, and the development of a production route for horse mackerel has been strongly encouraged.One of the first is to improve purity, natural The crystal contains high quality heavy metals,
Alpha ray emitters contain impurities, and in optical fibers, heavy metal impurities cause optical transmission loss.
For semiconductor single crystals - As a Higel crucible, the electronic and physical properties of the produced single crystal are low due to the penetration of heavy metal impurities. As a photomask substrate, it causes absorption loss due to impurities in the ultraviolet rays used for exposure, and as a light shielding material for semiconductor device encapsulants, alpha particles emitted from uranium impurities cause electrical malfunctions of devices. , each has 9 pieces of flat cloth! be desired. The second drawback is the generation of dust during the pulverization process and the contamination of impurities from the pulverization equipment, and it is expected that a method of pulverization that requires more time and less time will emerge. The third problem is resource constraints. The availability of natural crystals is limited and there is a risk of depletion. Efforts are being made to develop a new process using a halogenated silica or silicate ester, which is an intermediate starting from silica, which is relatively present in irises, and which is produced by a four-distillation process. The present applicant has already mentioned that Kozue 1Ii1'Js has made it especially easy to remove impurities from silicic acid! Eyes, E#: m
A powdery granular glue is produced by mixing ethyl silicate or propyl silicate, which has a low aromaticity with water in the ester, in the presence of an acid catalyst. Perfected the method of producing powder. This has a t-% tolerance (hereinafter referred to as tapered 1),
The disadvantage of this method is that the yield of quartz glass is relatively low at around 70 cm. In addition, the presenter proposed a method for producing quartz glass powder with a higher yield by using a mixed bath solution consisting of Nisdel silicate and a predetermined amount of plain water, or a silicate ester, a predetermined amount of water, and alcohol. The mixed bath solution is partially suspended in a dispersion medium that is substantially incompatible with the mixed bath solution, such as dodecane, to form powder gel gold, and the core/granular gel is fired to form quartz. The method of making glass powder has already been patented.
However, this 10,000 fl. (There is a drawback that the separation and recovery operations of the fermented ethyl to propyl silicate after the hydrolysis reaction of the fermented ethyl to propyl silicate and the dispersion medium are complicated. We sought to provide a method for producing quartz glass powder with higher yields (and easier handling), thus eliminating the need for multi-vertical dispersion media, such as in tapered U, and thus producing nucleated cane-shaped gels. Aiming to improve IC thin 1 so that the installation shoulder is not excessively large, we tested the catalyst for the formation of powdery gel at 117t9℃, and found that -C2 was achieved by using boric acid as an acid catalyst. The present invention has been reached, that is, the gist of the present invention is that n[kei, wave ethyl] to silicic acid in mol of ethyl silicate to ethyl silicate. A quartz quartz product characterized in that a powdery gel is produced by completely turbidating water containing 1 mmol or more and 300 mmol or more of boric acid per 1 mole of propyl, and the gel is separated and fired. In the present invention, the boron t sweetened in the produced quartz glass is determined by the addition of boric acid, the addition of the water, and the degree of washing of the quartz glass. Depending on the temperature of one baby and the firing time, etc., the addition amount of the boric acid is 31) per mol of the ethyl silicate or propyl silicate.If it is less than 1 mol, the amount of boric acid added is about 1/5 to 1/15 of the added boron. In addition, when cooling is performed over i o mmol, the amount of boron uride M is around 4 mmol per 1 mole of silica glass powder produced, regardless of the temperature difference.This opposite boron IA Although the quartz glass powder containing quartz glass powder is not necessarily suitable as a crucible material for pulling high-quality semi-quadramid single crystals, it is suitable for producing so-called multi-component optical fibers and photomask substrates. q!-There is no problem with the sealing material for the 4-body device except for 'C.As described above, the porcelain 11 used as the 1$ medium in the present invention
This method significantly improves the yield of quartz glass compared to the acid catalyst used in the above-mentioned taper 1, as shown in the example below.
Moreover, it has the unique feature that there is no problem even if a small amount of single-wave boric acid remains in the quartz glass of the product.
In particular, it varies greatly depending on the conditions involved in the production process of the upper 6-piece powder granule as a medium-sized body. On the other hand, the shape of the core quartz glass particles is mostly spherical with a radius of about 100 yen, but there are also some particles in which two to several spheres are condensed. Since particles in the form of hardened spheres are larger than monocytes, it is also possible to obtain spherical particle powder with a uniform particle size by classifying it using water, water, etc.
Next, the process of splitting quartz glass powder according to the present invention will be described in detail. (1) Preferably 1 mmol or more and 300 mmol or less of nuclei per 1 mole of ethyl silicate or propyl silicate for producing granular glue from raw material solution.
L < ri] Add 4 to 6 moles of water containing boric acid in an amount of 0 to 50 mmol and stir vigorously to keep the water in suspension and form a powdery gel. In the early stage of stirring this suspension, heating to a temperature of 856 C to a maximum of 856 C is effective for promoting the formation of the powdery gel and stabilizing it. The time required for the formation of the granular gel depends on the type of Nisdel silicate used as the raw material, the concentration of water, the amount of boric acid used, and the J1! ! Although it depends on the heating temperature of the suspension, etc., it can be determined by taking into account the data in the examples.2 It can also be determined from the milky white color of the suspension. Separation of powdery gel, drying*-[The produced powdery gel is separated from the mother liquor containing by-product alcohol.
After washing with water using a drying button such as a decanter, dry it. Although this cleaning is not necessarily an essential requirement, it is recommended to do so as a safety measure, as the alcohol contained in the powdered and granular gel evaporates during the drying and baking process. Firing process The firing temperature of the dried #granular gel is 1,000°C, which is the same as in the synthesis of quartz glass by the so-called Zorgul method.
It is a PlU bond, and the firing time depends on the firing temperature lW,
Approximately 1 hour is sufficient.The heating rate is not limited to a pestle, but when obtaining spherical particles, rapid heating must be avoided in order to prevent cracking of the particles.The powdery gel, which is the core of the present invention. Regarding the range of production ffi conditions, we assumed the range of the above 6 pins, but the reason for these limitations is the following Jr. (a) Usage amount of /jC The dizziness of water in the present invention is 4 mol or more and 6 mol or less per mol of ethyl silicate to 1-stage propyl silicate, or the amount of water used is per mol of ethyl silicate to propyl silicate. If it is less than 4 moles, the yield of the produced quartz glass powder will be extremely low, and if it exceeds 6 moles, cotton A-shaped lumps will easily be formed in the jilia (the desired powder-like gel will not be absorbed). Therefore, quartz glass powder cannot be obtained without the pulverization process. fbl Amount of boric acid added as an acid catalyst The amount of boric acid added in the present invention is 1 mmol or more per 1 mole of ethyl silicate or propyl silicate. It is in the range of millimole or more.

[If the amount is less than 1 mmol per mole of ethyl or propyl silicate, the improvement in the yield of quartz glass powder is not remarkable; This becomes virtually impossible, and instead of the granular gel, which is made up entirely of spherical particles, a coarse lumpy gel is produced, and quartz glass powder cannot be obtained without a pulverization process. The most desirable value is 10 to 50 mmol. tc) Nucleus Powder Formation temperature of granular gel Nucleus #Gel formation temperature (y is preferable because the formation speed is faster at a higher temperature, but the amount of water added to # If the MA suspension is heated to a temperature higher than 85°C while the hydrolysis of ethyl silicate or propyl silicate has not sufficiently progressed, the water contained in component 1 of the suspension will evaporate. , the so-called repeated recovery and reuse of unreacted and evaporated nuclear ethyl silicate or evaporated propyl silicate is insufficient for hydrolysis. However, after ffJ hydrolysis has sufficiently progressed, if the particles are heated to a higher temperature to promote solidification and stabilize the resulting powdery glue, deformation of one particle during operations in subsequent steps can be reduced. Since cracking, etc. can be prevented.It is particularly effective when trying to improve spherical particle powder. rKVc, This invention will be further explained in detail with reference to 2 examples. Unless possible, the following fruit d
It is not limited to U. At the helm 01 i,! Add r&ethyl 2231I7 (1 mol) to a three-purpose polyethylene flask (inner volume: 500, 5 liters), and add 1
．． 8! 90 ml of water containing M' (30 mmol) of boric acid
(5 mol) was added and the mouth of the Erlenmeyer flask was protected with an aluminum cap. As a result of vigorous stirring using a magnetic stirrer for 2.5 hours while heating at 60° CVC, the milky white color of the S suspension increased, so stirring was continued for an additional 0.5 hour. It was allowed to cool to room temperature. The supernatant was drained and the precipitated granular gel was washed by decantation with 50 ml of water 5 times and incubated at 0 °C for 8 h in an air oven for 2 then 15 h.
After drying at 0°C for 12 hours, it was placed on an alumina boat and heated to 1,000°C at a rate of 100'C/hour in a direct furnace. thing 55
) is good. The specific gravity of this fired product is 2.19=Sin, and the content is 499.
It turned out that it was 7 yen, and it turned into quartz glass powder. The boron-containing wrinkles were 0.4% as boron oxide. In addition, the silica yield based on ethyl silicate was 91%, which was confirmed to be significantly better than the 470% yield obtained when hydrochloric acid and Shuryoji's acid catalyst were used instead of boric acid. It was done. When the particles of the quartz glass powder were examined under an optical microscope, most of them were spherical with a diameter of around 50 μm, and some particles were coagulated with two or even individual particles. Particles with broken shapes were also found here and there. Example 2 Propyl silicate 576.11 (2 moles) was collected in a Teflon beaker (same number Mlffl), and boric acid 6.2?
(100 mmol) and 162,111C (9 mol) of water) were stirred for 6 hours using an impeller-type stirrer while maintaining the temperature at 25°C.
After stirring for 1 hour, the temperature was raised to 9000 °C, and stirring was continued for 1 hour, I9 was allowed to cool to room temperature while blowing on a scale. The resulting powdery gel was separated from the mother liquor and washed 4 times with 50 ml of water. Thereafter, it was dried in an electric oven at a temperature of 800°C for 8 hours, and then at a temperature of 120°C for an additional 8 hours. Place the dried #congratulations letter on an alumina boat? in the air furnace at a speed of 00°C], (raised the temperature to 100°C and fired at this temperature for 1 hour to produce 102f of powdered and granular fired product. The content of the hopper is 99.5%, and the hopper content is 0.43% as boron oxide and °C1
It has been found that silica glass powder can be obtained with a silica yield of 85 cm based on the globil silicate. In addition, most of the particles of the quartz glass powder were one wheel-ball, and some of the particles were found to be two or several particles of one object condensed, but those in the shape of broken spheres were easily recognized. Umi IIJi Hei 3 Distilled 4NI produced Propyl 288 mJ (1 mole)
was placed in a polypropylene Erlenmeyer flask, and high-purity L (boron oxide 3
．． Add 5P (100 mmol) dissolved in 108 ml (6 mol) of sound source water, cover the mouth of the Erlenmeyer flask with aluminum foil, heat to 85°C, and stir for 5 hours with a magnetic stirrer. After separating the resulting powdery gel from the mother liquor, it was mixed with 50 ml of steamed water heated to 45°C.
Washed twice and heated to 120°C in open air for 18 days.
Dry for an hour. The powdered gel after dry KL was placed in a quartz glass boat and heated at 4If at 200°C/hour in an electric furnace.
+4 degrees 1,050°CK temperature increase. The mixture was stirred for 30 minutes to obtain #granular baked products of 48.5F. The silica content of this fired powder is 99.5%. The boron-containing twill is 0.39% as boron oxide. As a result of emission spectroscopic analysis, no impurities other than boron were detected, indicating that the powder was a highly pure boron quartz glass powder. Incidentally, the silica yield is over 80 based on the propyl silicate. Leprosy Example 4-1O The pupil water and boric acid tank shown in Table 1 were used. Temperature of a suspension of boron-containing water in ethyl chloride: 55°
The leprosy was treated under the same conditions as Example 1, except that C was used, and the quartz glass powder was mounted, and the results are shown in Table 1.
As shown by 1m, in Examples 4 to 10, the quartz glass powder was all submerged at a high yield. 1st Clothing Comparison Period 1-5 Using the water and Hou 711 shown in the 2nd Clothing, this Zahou Fountain T-? a. Set the temperature of the cloudy liquid to 55°.
The quartz glass was crushed into gold by processing under the same conditions as in Example 1, except for C, and the results are shown in Figure 2. As shown in the second experiment, when the amount of water added per mole of ethyl silicate is lower than 4 moles, and when the concentration of hydrochloric acid is lower than 1 mmol, the yield is extremely low. In addition, if the concentration of water added per 1 mol of ethyl ethyl is more than 6 mol, the liquid containing more than 300 mmol of boric acid will produce lumpy gel instead of the desired powdery gel. I couldn't be arrogant. 2nd % Permitted NA Person Mitsubishi Kin R Co., Ltd. Representative Yoshi Nao Shirakawa 169-

Claims (1)

[Claims] (11tI[1 mmol or more per mol of the ethyl silicate or #propyl silicate in 1 mol of ethyl silicate or propyl silicate
A method for producing quartz glass powder, which comprises suspending 4 mol or more and 6 mol or less of water containing 00 mmol or less of boric acid to form a powdery gel, and separating and firing the core powder/granular gel. .