JPS596815B2 - Glass manufacturing method using preheated raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing glass, and more specifically, a glass raw material (glass batch) is preheated before being introduced into a melting furnace and then introduced into a glass melting furnace to manufacture glass. Regarding the method.

In recent years, energy conservation has been promoted in all sectors of the industrial world, and in the glass industry, in order to reduce energy costs for glass melting, waste heat from glass melting furnaces is used to pre-melt glass batches at temperatures above 200℃. A method has been proposed in which glass is produced by heating the glass to a temperature below the starting temperature and then charging the glass into a glass melting furnace.

Soda-lime glass, which is produced in large quantities as container or sheet glass, is produced from glass batches using sulfates and/or sulfites as melt accelerators and fining agents, with the addition of sulfates as reducing agents to further enhance the fining effect. It is common to add carbon during the glass batch.

However, since carbon is immediately oxidized when heated, it cannot be expected to be effective as a reducing agent when a preheated glass batch is put into a glass melting furnace.

Therefore, in order to carry out the glass manufacturing method in which a glass batch is preheated and put into a glass melting furnace, it is necessary to use a reducing agent other than carbon that is not easily oxidized, as previously proposed by the present inventors in Japanese Patent Application No. 52-97231. or if carbon is used as a reducing agent, measures must be taken to ensure that the required amount of carbon is present at the time the preheated glass batch is introduced into the melting furnace.

The present invention embodies the latter concept.

According to the present invention, carbon itself is not added to the glass batch in advance as a reducing agent, but an organic compound containing carbon atoms in its molecular structure is added to the glass batch before the glass batch is preheated, and the glass batch is heated to a predetermined temperature. The organic compound is carbonized into carbon in the process of being preheated to a certain temperature, so the amount of heat energy applied after it becomes carbon is significantly lower than in the past, making it difficult to oxidize. When the resulting glass batch is introduced into the melting furnace, a necessary and sufficient amount of carbon is present as a reducing agent, and the glass batch can be preheated to a higher temperature than in the past.

Organic compounds that can be used in the method of the present invention include heavy oils, phenols, polyhydric alcohols, fatty acids, sugars, starches, and the like.

In carrying out the present invention, the organic compound may be added to the glass batch in advance, but since the reducing agent reacts with the fining agent during the vitrification reaction, the fining agent and the organic compound may be added in advance. It is preferable to add the reducing agent to the glass batch after sufficiently mixing it in advance, since the effect of the reducing agent will be more pronounced.

To control the carbonization of organic compounds more precisely, the mixture of organic compounds and clarifiers is treated in a heating furnace with a protective atmosphere that prevents extreme oxidation of the organic compounds, and the organic compounds are thermally decomposed and carbonized. The recommended method is to add this to a residual glass batch that has been preheated in a separate conventional heating furnace and then feed it into the glass melting furnace.

This method has the advantage that the amount of atmosphere to be adjusted is small.

Next, the effects of the present invention will be described.

A normal glass batch containing Glauber's salt (Na2SO4) as a clarifying agent and carbon as a reducing agent was preheated at a high temperature and then melted in a melting furnace. When the number of bubbles per unit volume of the resulting glass was measured, it was found that the batches had the same composition. The number of bubbles was about 100 times that of glass produced by melting under the same conditions without preheating.

This means that most of the carbon used as a reducing agent is oxidized by preheating before it is introduced into the glass melting furnace, so it does not substantially act as a reducing agent, and the effect of the fining agent in combination with Glauber's salt is fully demonstrated. means not.

Next, we adopted heavy oil as an inexpensive organic compound, added and mixed an appropriate amount of it to a glass batch containing mirabilite, preheated the glass batch to a high temperature under the same conditions as above, and melted the resulting bubbles in the glass. The number was almost the same as that of glass produced by melting without preheating.

According to the present invention, for example, by using cheap heavy oil as a reducing agent, the waste heat of the glass melting furnace is effectively used to preheat the glass batch to a considerably high temperature.
This shows that glass of the same quality as conventional glass can be obtained even when put into a glass melting furnace, and the economic effect of energy conservation is significant.

In addition, in the present invention, the glass raw material includes not only a normal finely powdered glass batch but also a granular batch obtained by granulating a finely powdered glass batch in advance. , granular batches are preferred.

Moreover, when preheating is performed using a granular batch, the thermal conductivity of the batch itself, which is made by granulating a glass batch of fine powder, is relatively small. Preferably.

In order to further improve thermal efficiency, it is desirable to preheat the pulverized glass batch and then granulate the pulverized glass batch immediately before charging it into the melting furnace.

Next, an illustrated example of an apparatus for carrying out the present invention will be described.

1.2, 3, and 4.5 in the figure are silos for storing various raw material powders for glass batches. Organic substances as fining agents and reducing agents are also stored in these silos, but if the organic substances are liquid, for example powder It will be placed in a suitable liquid container instead of the body silo 5.

Weighing machines 6, 7, 8, 9.10 are installed under the silo, and the raw materials weighed by these are transferred to conveyor 1.
1 to the mixer 12.

If the organic matter is present as a liquid in a container instead of the silo 5, the weighing device 10 corresponding to the container may be, for example, a metering pump.

When using a liquid as the organic substance, it is better to weigh the liquid near the mixer 12.

That is, in order to prevent the conveyor 11 from being contaminated by liquid organic matter, when supplying the liquid organic matter to the conveyor 11, other powder raw materials are allowed to fall onto the conveyor 11 first, and then placed on top of the other raw materials deposited on the conveyor 11. This is because it is preferable to supply it.

The glass batch mixed by the mixer 12 is fed by a conveyor 13 to a glass batch silo 14 .

The process from weighing the raw materials to supplying the glass batch to the silo 14 is performed intermittently.

From the batch silo 14, the batch is sent by a continuous metering device 15 to a heating furnace 16 where the glass batch is preheated.

A preheated glass batch containing an appropriate amount of carbon produced by carbonization of organic matter, which has come out of the heating furnace 16, is fed into the glass melting furnace 20 by a continuous quantitative feeder 17.

High-temperature waste gas is fed into the heating furnace 16 from a melting furnace 20 through a conduit 18 .

The waste gas exchanges heat with the glass batch in the heating furnace 16 to heat the glass batch, and then passes through the conduit 19 and is discharged as waste gas from the chimney.

Although the type of heating furnace 16 is not specified, it is preferable to control the atmosphere of high-temperature gas used in heating furnace 16 in order to control carbonization of organic matter.

For example, if the amount of oxygen in the waste gas from the glass melting furnace 20 is too large and organic matter is burned, the waste gas may be transferred to the heating furnace 16.
It is possible to burn fuel in the waste gas before sending it to the waste gas to increase the temperature of the waste gas to increase the preheating efficiency of the glass batch, and to reduce the amount of oxygen in the waste gas to control the carbonization of organic matter.

However, in the sword mouth thermal furnace 16, the amount of heat used to heat the glass batch is generally large, so even if the glass batch is heated using waste gas from the melting furnace 20, for example, the amount of waste gas used will be large. When the temperature and amount of waste gas are sufficient, it is not advisable to control the amount of oxygen in all the waste gases used in the heating furnace 16 in order to control the carbonization of organic matter.

In such a case, only the sulfate and/or sulfite of the clarifier and the organic matter are mixed in advance, and the mixture is preheated with high-temperature gas with a controlled oxygen concentration to carbonize the organic matter, thereby producing a clarifier containing the desired amount of carbon. After preparing a high-temperature mixture of carbon and carbon, the above-mentioned high-temperature mixture is added to a batch containing no fining agent and carbon, which has been preheated in a heating furnace without separate atmosphere control, and the mixture is charged into a glass melting furnace. be able to.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing an example of an apparatus for carrying out the present invention. 1, 2, 3, 4.5... Glass raw material silo, 6
,7,8,9,TO...Weighing machine, 11.13.
... Conveyor, 12 ... Mixer, 14
...... Batch hopper, 15... Continuous quantitative feeding device, 16... Heating furnace, 18.19...
...Gas pipe, 20...Glass melting furnace.

Claims (1)

[Scope of Claims] 1. A glass manufacturing method in which a glass raw material containing sulfate and/or sulfite as a fining agent and to which a reducing agent is added is preheated before being introduced into a glass melting furnace, as the reducing agent: A method for producing glass, characterized in that an organic compound that is carbonized by the preheating is used. 2. The method according to claim 1, wherein the organic compound and the sulfate and/or sulfite are mixed in advance and then added to the remaining glass raw material. 3 The remaining glass raw material obtained by heating a mixture of an organic compound and a sulfate and/or a sulfite in an atmosphere that prevents oxidation of the organic compound to carbonize the organic compound, and then heating the mixture in an atmosphere separate from the mixture. 2. A method according to claim 1, characterized in that the method is characterized in that: 4. Method 1 according to claim 1, characterized in that the glass raw material is granulated.