JPS62226822A - Production of glass - Google Patents

Abstract

PURPOSE:To prevent uneven distribution of temp. in the inside of a dryer and to produce glass free from bulk cracking due to wind by separating bulk obtained by gelation from the atmosphere in the chamber of the dryer and forcedly convecting the outside atmosphere. CONSTITUTION:Bulk is obtained by using at least metallic oxide, metallic alkoxide and an acid catalyst and allowing the mixture to gel by a sol-gel process. The obtained bulk is separated from the atmosphere in the inside of a dryer in some degree and introduced into the dryer and dried while forcedly convecting the outside atmosphere.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing glass.

[Summary of the invention]

The method for producing glass by the sol-gel method involves using metal alkoxide or silic fine particles as a t-raw material, gelling the resulting bulk, drying it, and sintering it to form a dry gel.

In the bulk drying process of glass production using the sol-gel method, the present invention isolates the bulk from the atmosphere inside the dryer chamber to some extent and causes the outside atmosphere to undergo forced convection.
This prevents the bulk from cracking due to wind, prevents uneven temperature distribution within the dryer, and improves drying yield.

[Conventional technology]

The conventional method for manufacturing glass using the sol-gel method is (I￥
! Unlike in 1982-257577), the bulk and the atmosphere inside the dryer chamber were not isolated, nor was forced convection of the outside atmosphere performed.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional technology, there is a problem that uneven temperature distribution exists in the dryer chamber, and when the atmosphere is convected to eliminate this, the bulk cracks occur due to the wind, and it is not possible to stabilize the dryer. Has a point.

The present invention is intended to solve all of these problems, and its purpose is to improve and stabilize the drying yield.

[Means for solving problems]

In order to solve the above problems, the method for producing glass of the present invention includes: when drying the bulk obtained by gelation,
The characteristics are that the bulk and the outside atmosphere are separated and the entire outside atmosphere is dried by forced convection.

[Effect]

The bulk left behind by the sol-gel process shrinks significantly upon drying. Furthermore, the shrinkage rate differs depending on the degree of drying, and if the drying is partially uneven, the bulk will become distorted and will not be able to withstand stress and will crack. The same can also be said about the surface and inside of the bulk. In other words, if the drying rate of the surface of the bulk and the diffusion from the inside to the surface are not balanced, stress due to strain will be generated on the surface and inside, which will also result in cracking. Therefore, in the drying process, it is important to eliminate uneven drying due to temperature, wind, etc. as much as possible and to provide stable drying conditions.

Therefore, according to the above configuration of the present invention, it is possible to eliminate uneven temperature distribution within the dryer and prevent cracking due to wind, and it is possible to improve and stabilize the drying yield.

〔Example〕

17.9 tons of tetraethyl orthosilicate, 2 and 5 L of 101 N hydrochloric acid, and 10 Kfi of finely powdered silica were mixed and hydrolyzed with vigorous stirring to obtain a white sol. This sol solution was heated at 28 K while keeping it at 25°C to 30°C.
The mixture was stirred while applying ultrasonic waves of Hz for t-4 hours. Furthermore, the obtained sol solution fL was transferred to a centrifuge at 45.1500G.
was applied for 10 minutes to separate coarse particles, and then 1
A uniform sol solution free of coarse particles was obtained by filtration through a μm filter.

P)i of the obtained sol solution with 01 N ammonia aqueous solution
i Adjust to 4.2 and then put in a polypropylene container (3
4 x 26 cm x 10 pieces) with a thickness of 1 m.

When it was left in a sealed state for 2 days, it gelled and shrunk by about 5X in terms of linear shrinkage. Next, the lid with holes with an open area ratio of 14% was replaced, and the lid was placed in a dryer. Inside the dryer, polypropylene containers T1 were placed in units of 10 units, and the containers were surrounded by a curtain behind the polypropylene to prevent hot air from the hot air outlet in the dryer from directly entering the containers behind the polypropylene.

The temperature inside the dryer was maintained at 60°C, and drying was carried out in this state for 15 days to obtain a dry gel of approximately 22cfRX17.5cm (L5.).Furthermore, this dry gel was dried at 80°C.
It was placed in a confectionery container and dried for 2 days to sufficiently remove moisture.

The resulting dry gel was placed in an air oven and heated at a rate of 30°C.
The temperature was raised to 200°C at a rate of 200°C/hour, and the temperature was maintained at 200°C for dehydration. The temperature was again raised to 450° C. at a heating rate of 50 C/hour and held at 450° C. for 6 hours to remove organic residues by oxidation. Next, the inside of the furnace was changed to a helium atmosphere, and the temperature was again raised to 700°C at a rate of 60°C/hour, and maintained at this temperature for 2 hours. Similarly, the heating rate was 60°C/hour to 800°C, 9
The temperature was raised to 1250°C using a program of holding each temperature for 2 hours at 00°C, 1000°C, and 1150°C.

The resulting milky white opaque glassy substance was placed in an atmospheric furnace.
The temperature was raised to 1550°C at a heating rate of 200°C, held at this temperature for 2 hours, and then allowed to cool naturally.
5. A quartz glass of XI553X14- was obtained.

〔Effect of the invention〕

As explained above, the present invention prevents uneven temperature distribution within the dryer by isolating the bulk and the atmosphere inside the dryer chamber in the drying process and causing forced convection of the entire outside atmosphere.
This completely prevents bulk cracking due to wind and improves drying yield.

that's all

Claims (1)

[Claims] In a glass manufacturing method using at least a sol-gel method using fine particles, when drying the bulk obtained by gelation, the bulk is isolated to some extent from the atmosphere inside the dryer chamber, and the outside atmosphere is forced to circulate to dry the bulk. A method of manufacturing glass characterized by: