JPS6038647Y2 - Silica molten lump production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for producing a molten silica ingot, and more particularly, to an apparatus for producing a molten silica ingot that is uniform in size and shape.

With the increasing demand for fused silica as a refractory material for continuous casting immersion nozzles and coke ovens, mass production began using electric furnaces and gas heating furnaces.

However, even though these fused silicas produced as raw materials for ceramics have almost no physical problems, uneven voids remain between and inside the raw material particles, and even in the structure of parts without voids, there are irregularities. Microstructures and granular structures are observed.

When using this as a raw material for ceramics, it is crushed into various sizes, blended with particle size, shaped and burned to obtain a molded product, so non-uniformity of the melt is not a problem, but the melt can be directly machined. When an industrial product having a desired shape is formed by heat processing or heat processing, large voids remain in the industrial product or cracks tend to occur due to internal strain, making it unusable.

For this reason, various studies have been carried out to produce fused silica homogeneously, one example of which is the
There is one described in Japanese Patent No. 4211.

However, this manufacturing method and manufacturing apparatus have irregular shapes, are difficult to manufacture in large sizes, and are extremely time consuming, making them unsuitable for mass production of homogeneous fused silica.

That is, the manufacturing apparatus described in Japanese Patent Publication No. 46-4211 surrounds a rotatably supported refractory support plate with a furnace body, and a burner is mounted eccentrically on the upper part of this refractory support plate. This equipment produces fused silica by melting quartz powder with a flame focus and stacking the molten layer on a fireproof support plate.

However, with this device, the quartz powder can only be melted at or near the flame focus of the burner.
Since the melting area is limited to a very small area, it takes time to melt the quartz powder, making it unsuitable for mass production.

In addition, in this manufacturing equipment, the fused silica is formed by stacking the molten layer on the refractory support plate at a location corresponding to the focus of the burner flame, so the shape of the fused silica is limited to a columnar shape, and its dimensions are limited to the refractory support plate. determined by the distance between the central axis of the burner and the flame focus of the burner;
It is difficult to obtain melts with large dimensions.

The purpose of the present invention is to solve the above-mentioned drawbacks, and in particular, to produce fused silica that homogeneously melts powdered or granular silicon dioxide raw materials and that can be easily and economically produced even in the form of molten silica ingots with large dimensions and shapes. The purpose is to propose a molten ingot manufacturing device.

That is, in the present invention, a burner is provided at the top of a melting chamber where powdered or granular raw materials are melted to form a molten material, and a burner is disposed at the bottom of the melting chamber for dispersing the raw materials together with fuel into the melting chamber. A passage is provided, and a constriction is formed in the discharge passage, a dispersion chip for the raw material is provided at the lower end of the burner, and a combustion gas outlet is provided at the upper part of the melt in the melting chamber. It is characterized by

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

In addition, FIG. 1 is a sectional view of one embodiment of the present invention,
FIG. 2 is a sectional view of the burner shown in FIG. 1.

In addition, in FIGS. 1 and 2, reference numeral 1 indicates a furnace body, and 2
is a through hole, 3 is a burner, 4 is a central cylinder, 5 is an inner annular pipe,
6 is an outer annular tube, 7 is a melting chamber, 8 is a melt, 9a, 9b
10 is an exhaust port, 10 is a dispersion chip, 11 is a constriction part, and 12 is a melt discharge passage.

In FIG. 1, a furnace body 1 is constructed from a refractory material such as zirconia brick, and is surrounded by the furnace body 1 to form a melting chamber 7 approximately in the center.

A through hole 2 is formed at the top of the furnace body 1, and the through hole 2 penetrates approximately the center of the melting chamber 7, and a burner 3 is inserted through the through hole 2.

This burner 3 is different from a normal burner in that it is configured so that in addition to supplying fuel, silicon dioxide powder can be uniformly supplied into the furnace as a raw material.

Therefore, as shown in FIG.
Construct from 0.

By configuring the burner 3 in this way, when the raw material silicon dioxide powder is charged from the upper hopper 4a of the central cylinder 4, the raw material powder can be uniformly and continuously supplied from the burner 3 to the melting surface in the melting chamber 7.

Further, when fuel such as hydrogen is supplied from the conduit 5a and oxygen is supplied from the conduit 6a, the fuel is supplied to the inner annular pipe 5.
After that, the oxygen passes through the outer annular pipe 6 and burns through diffusion contact at the tip of the burner 3, and enters the melting chamber 7, where the entire area is uniformly heated to a high temperature, for example, easily heated to about 1800 to 2300°C. Can be maintained.

Furthermore, when the temperature of the melting chamber 7 is within this range, a homogeneous fused silica ingot can be produced.

That is, when melting silicon dioxide powder or the like in the melting chamber 7, if the temperature of the melting chamber falls below 1800°C,
The degree of melting of the quesochloride dioxide powder tends to be uneven, which not only makes the melt non-uniform, but also tends to make the descent of the melt less smooth from the discharge passage 12, as will be described later.

Furthermore, if the temperature of the melting chamber 7 exceeds 2300° C., the furnace material not only reacts with the melt and gets mixed with it, but also significantly shortens the life of the furnace.

As described above, a melting chamber and a burner are arranged, a discharge passage 12 is formed downward from the bottom of this melting chamber 7, and the melt 8 is sequentially lowered into the melting chamber 7 from this discharge passage 12,
Further, a portion of the discharge passage 12 is constricted to form a constricted portion 11 on its inner wall surface.

When the discharge passage 12 and the constriction part 11 are configured in this way, the melting chamber 7 is completely sealed by the descending melt 8, and the melt 8 is cooled and can be easily discharged as a solid state. can be melted with a certain level of melting surface, and a uniform molten silica ingot can be produced.

That is, when discharging the melt without forming any constriction in the discharge passage formed downward from the bottom of the melting chamber, the entire outer circumference of the melt 8 descends while contacting the wall surface of the discharge passage. Although it is cooled, fused silica inherently has a high viscosity even at high temperatures, and the viscosity increases rapidly as the temperature drops, so the molten material tends to stick to the discharge passage.

If this is forced to fall, the furnace material will be destroyed, making continuous production impossible.

In addition, if there is no throttle part and the molten material is cooled while being in contact with the entire wall surface of the discharge passage, the cross-sectional area of the melting tank and the discharge passage are the same. It is difficult to obtain a homogeneous molten material because the molten surface easily changes due to fluctuations in the descending speed, and the molten state changes.

On the other hand, when the discharge passage 12 has the constricted portion 11 as in the device of the present invention, the area around the descending melt 8 can be completely sealed, and almost no heat is scattered from the melting chamber 7. do not have.

Therefore, the melting chamber 7 can be easily maintained at a high temperature and at the same time can be controlled to an appropriate temperature.

In addition, from this point of view, if the raw material powder is uniformly spread from the burner 3, the raw material powder can be melted over the entire area of the melting chamber 7.

Further, when the constricted part 11 is present in the discharge passage 12, only a part of the molten body 8 is cooled by the constricted part 11, and the temperature can be maintained at a temperature higher than the fixing temperature and at which the external shape does not change.

Further, since the discharge passage is made smaller than the melting tank by the constriction part, even if the amount of raw material thrown, the combustion state, and the descending speed of the melt vary, the fluctuation of the melting surface is extremely small, and the melted state can be maintained constant.

Therefore, according to the apparatus having the above-mentioned configuration, not only a homogeneous ingot can be produced, but also the ingot can be smoothly discharged without sticking to the discharge passage 12.

Further, when the constricted portion 11 is provided in the discharge passage 12 as described above, it is preferable that the constricted portion 11 be configured to be freely inserted into and removed from the furnace body 1.

This is because when changing the size and shape of the ingot, the distance between the constricted parts 11 can be easily changed by replacing the constricted parts 11, and the constricted parts 11 are different from other parts of the furnace body 1. This is because it is extremely easy to wear out.

Further, the melting chamber 7 configured as described above is provided with exhaust ports 9a and 9b on both sides to exhaust combustion exhaust gas,
Further, it is preferable that the exhaust ports 9a and 9b be provided with, for example, a damper (not shown) to control the exhaust gas velocity.

That is, the raw material powder thrown from the central cylinder 4 of the burner 3 is melted in the melting chamber 7, but if the particle size of the raw material powder is too small, it is likely to scatter from the exhaust ports 9a, 9b.

From this point of view, the particle size of the raw material powder is preferably about 1.0 to 0.1 rfrIn, but even in this case, scattering of the raw material powder can be sufficiently prevented by appropriately adjusting the damper opening and controlling the exhaust gas speed. .

Next, the effects of the device of the present invention having the above-mentioned configuration will be explained through its usage mode.

First, raw material silicon dioxide powder is supplied from the center cylinder 4 of the burner, hydrogen and oxygen are supplied from the inner and outer annular pipes 5 and 6, and the melting chamber 7
At the same time, hydrogen and oxygen are combusted within the melting chamber 7, and at the same time, the raw material powder is spread and melted over the entire area within the melting chamber 7.

Incidentally, in order to uniformly spread the raw material powder, it is possible to easily spread the raw material powder by attaching a dispersion tip 10 to the tip of the burner 3.

Next, the melt surface of the raw material powder is maintained at a constant level and the melt
is sequentially and continuously lowered, and during this descent, the melt 8 is cooled from the constriction section 11, and the melt 8 that has passed through the constriction section 11 is cooled in the atmosphere to produce a homogeneous molten silica ingot. do.

By melting the raw material powder and producing it using the apparatus of the present invention, a homogeneous molten silica ingot with large size and shape can be easily produced, and at the same time, a homogeneous molten silica ingot can be produced in a relatively short time.

Melting silicon dioxide in a burner or the like requires a considerably high temperature, and such high temperatures can generally only be obtained at the focal point of the burner flame.

For this purpose, in the conventional method, as shown in Japanese Patent Publication No. 46-42111, the raw material powder is melted at the focus of the burner flame.

However, if it melts at the focus of the burner flame,
Because the melting zone is narrow and limited, melting takes a relatively long time.

On the other hand, in the case of the apparatus of the present invention, the periphery of the descending melt 8 is sealed by the constriction part 11, and the melting chamber 7 is completely sealed.

For this reason, the melting chamber 7 is maintained at a uniformly high temperature, and the raw material powder spread over the entire area of the high-temperature melting chamber is uniformly melted, and the melting is carried out in a short period of time, and it is easily possible to produce large-sized homogeneous powders. Fused silica ingots can be produced.

Next, an example of actual use of an example of the device of the present invention having the above configuration will be described.

The furnace body 1 having the structure shown in FIG.
A constriction part 11 with a diameter of 340 mm is provided and the melting chamber 7
The dimensions were set to 360 x 46-, and a burner 3 having the structure shown in Fig. 2 was set on the top.

In an apparatus with this configuration, Korean silica (particle size 1.OO, 1, mm) is thrown from the central cylinder 4 of the burner 3 at a rate of 20 kg/hour, and at the same time, hydrogen gas 4QNd/hour is thrown from both the inner and outer annular pipes 5, 6. When oxygen gas was supplied at a rate of 2ONd/hour, the temperature in the melting chamber 7 was maintained at 1950 to 20500C and melted.

Next, the melt 8 is lowered from the discharge passage 12 at a rate of 12 to 13 cm/hour, and at this time, the melt 8 is lowered from the tip of the burner 3 by 40 cm/hour.
Melting was continued while maintaining the molten surface of the raw material powder between the constriction parts 11 and 15 to produce prismatic fused silica having a cross-sectional dimension of 330 x 23.

Finally, the true porosity of the fused silica produced in this way was determined to be 3.0 to 5.5%, and there was no problem at all when it was processed into industrial products.

[Brief explanation of the drawing]

Figure 1 is a sectional view of one embodiment of the present invention, and Figure 2 is a cross-sectional view of one embodiment of the present invention.
3 is a cross-sectional view of the burner of the embodiment shown in the figure; FIG. Code 1...Furnace body, 2...Through hole, 3.
... Burner, 4 ... Center cylinder, 5 ...
...Inner annular tube, 6...Outer annular tube, 7...
...Melting chamber, end...Melted body, 9a. 9b...exhaust port, 10, tune, dispersion chip, 11
. . . Restricted portion, 12 . . . Melt discharge passage.

Claims (1)

[Scope of utility model registration request] A burner for dispersing the raw material together with fuel into the melting chamber is provided at the top of the melting chamber where the powdered or granular raw material is melted to form a molten body, while a discharge passage for the molten body is provided at the bottom of the melting chamber. Moreover, a constriction part is formed in the discharge passage, and a dispersion chip for the raw material is provided at the lower end of the burner, and a combustion gas discharge port is provided at the upper part of the melt in the melting chamber. Equipment for producing fused silica lumps.