JPS604128B2 - Fused silica production method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing fused silica and an apparatus therefor. More specifically, the present invention provides a method for producing fused silica and an apparatus therefor. The present invention relates to a method for producing fused silica, in which granular and/or lumpy silicon dioxide particles are heated and melted, and an apparatus therefor.

Fused silica is made by heating and melting silicon dioxide, which has relatively few impurities, and is currently mainly used in fire-resistant materials and electronic materials.

However, as electronic technology advances, high purity and high quality products are required, and fused silica used as a sealing material for electronic components is also required to contain a small amount of Q-rays. Several methods have been proposed for producing fused silica.

For example, there is a method in which silicon dioxide is melted by generating an arc with a carbon electrode, or a method in which silicon dioxide powder is supplied as a raw material to a furnace body using zirconia bricks and melted using an oxyhydrogen flame. However, since the former method uses a carbon electrode, carbon gets mixed into the fused silica and it is difficult to separate and remove it, so the latter method is currently mainly used. However, when the latter method is used as a resin sealing material for electronic materials such as transistors and ICs, there is a drawback that uranium, which is present in the zirconia bricks of the furnace material, is mixed into the material. Therefore, even if the raw material silicon dioxide containing only a small amount of impurities is selected, which is then crushed, flotated, or treated with acid, or other suitable impurity removal methods are used, the furnace material for fused silica production equipment may be used. It is unavoidable that impurities are mixed into the fused silica. The purpose of the present invention is to solve these drawbacks, and the present invention uses silicon dioxide with a low impurity content and is designed to prevent direct contamination of impurities. The present invention aims to provide a method and an apparatus for producing fused silica with a low content of impurities, particularly uranium, by heating a raw material silicon dioxide lump on top of the silicon dioxide block and heating it at high temperature from the upper part of the furnace. That is, the first aspect of the present invention is to produce fused silica using a closed furnace that heats and melts raw material silicon dioxide by feeding it onto a movable hearth. Pump fused silica grains with a grain size of 1 to 25 grains, and on top of them, a raw material silicon dioxide lump with a grain size of 30 to 10 grains, and while moving them, heat to a temperature of at least 1750 °C.
The second invention is a method for producing fused silica, which is characterized by heating to a temperature of 100 mL or higher, and the second invention is a closed furnace in which raw material silicon dioxide is heated on a movable hearth and heated while moving. The fused silica manufacturing apparatus is characterized in that a container made of a heat-resistant material is placed above the hearth, in which fused silica grains and raw material silicon dioxide lumps are layered thereon. The present invention will be further explained below with reference to the drawings.

The drawings show a fused silica manufacturing apparatus according to an embodiment of the present invention, in which FIG. 1 is a front cross-sectional view of the apparatus, FIG. 2 is a side cross-sectional view, and FIGS. Fig. 5 is a side cross-sectional view of another embodiment.First, as shown in Figs. Furthermore, a water-cooled stainless steel furnace cover 3 equipped with an oxyhydrogen burner 5 is disposed on the upper surface of the hearth. The grains 6 and then the raw material silicon dioxide 7 are layered one after another, and are heated and melted by the upper oxyhydrogen burner 5 while moving.

On both longitudinal sides of the furnace body 1, there are provided entrances that can be opened and closed and serve as entrances and exits for a movable hearth. Further, a quartz glass plate 4 is fixed to the inside of the stainless steel container 2 using, for example, an inorganic adhesive to prevent direct contact between the stainless steel container 2 and the raw material silicon dioxide.

In this way, impurities will not be mixed in. Figures 1 and 2 show the case where there is one stainless steel container 2, but if the furnace body is large as shown in Figures 3 and 4, one or more containers may be used. This makes it suitable for mass production.

In this case, as shown in FIGS. 3 and 4, a moving device 8 such as a long truck and endless track is used, respectively. However, as shown in Figure 5, a structure in which the hearth moves up and down requires a larger support device to move the hearth up and down, so it is difficult to make it too large. This has the advantage that temperature control and handling are easy.

The shape of the furnace body is not particularly limited and can be of various shapes such as cubic or rectangular, and the stainless steel container can be moved on a moving device 8 such as a trolley or endless track. That's fine. The moving device 8 may be made of a heat-resistant material, as long as it is movable without being deformed by heating.Also, the moving device 8 does not need to be particularly cooled, but it will be easier to take out the product if it is water-cooled. In this case, heat dissipation increases, so it is preferable to attach a refractory material such as a quartz glass plate to the inside of the stainless steel container as described above. It is installed so that it is injected directly into the raw material in the stainless steel container 2.The fuel for the burner is hydrogen,
Gaseous substances such as propane are preferred. Moreover, in order to improve the thermal efficiency of the furnace body and extend its life, it is preferable to provide a heating chamber in front of the furnace body and a cooling chamber at the rear thereof.

Next, a method for producing fused silica using the apparatus of the present invention will be explained.

A quartz glass plate 4 with a thickness of 1 to 1 mm, preferably about 5 ribs, is adhered to the stainless steel container 2 with an inorganic adhesive, and fused silica particles 6, for example, 1 to 3 dia. Spread the material evenly on the bottom of the container, and place the powder on top of it.
15 layers of raw material silicon dioxide, preferably 40 to 40,000 ml, are layered.

While moving such a stainless steel container 2 using the above-mentioned moving device, a temperature of 1750°C is applied from the top or side of the furnace.
Heat to over 0.00.

In this case, the raw material silicon dioxide is affected by the impact caused by heating.
When it is coarsely crushed and kept in a high-temperature area in the furnace for a certain period of time, it becomes a melt, which is then cooled and becomes a product.

As explained above, the present invention has a stainless steel container placed on a moving device, molten silica grains in this container, raw material souls placed on top of the container, and heated while moving the molten silica particles. According to the present invention, there is a silica manufacturing apparatus that does not allow impurities to be mixed in from the rhombus barrel, requires less power for finely pulverizing raw materials, and is capable of continuous production without welding to a stainless steel container. This is an excellent device that can take out products at any time.

A more detailed explanation will be given below with reference to Examples.

EXAMPLE Fused silica was produced using an apparatus having the structure shown in FIGS. 1 and 2.

A cubic furnace body measuring 100 mm long, 100 mm wide, and 100 mm high was used, and the furnace was operated under the conditions shown in Table 1.

The container is made of stainless steel, covered with a quartz plate with a thickness of 5 ribs, or made of alumina, and its dimensions are 500 mm.
A size of ×500 × 8 proboscis was used. This container is filled with lk9 of fused silica particles with a particle size of 6 to 25 m'm as a mat, and 6 k9 of raw material Frog Stone Soul 40 to 100 m'w is placed on top of it.
Fill it, place it on a moving device, and while moving it heat it to 175 psi with an oxyhydrogen flame burner from the top of the furnace.
It was held at that temperature for 18 minutes and cooled. Although some of the molten material adhered to the fused silica grains, it did not adhere to the quartz plate. By pulverizing the fused silica produced according to the present invention
As determined by linear analysis, cristobalite and Q
It contained no quartz and was 100% fused silica.

In addition, when the Q-dose was measured using a halophotometer, it was 1
Misaki PB and ``Those made by the conventional method using the same raw materials are 1
It was 0 plate pb.

table

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a front sectional view, FIG. 2 is a side sectional view, and FIGS. 3, 4, and 5 are side views of other embodiments. FIG. Code, 1... Furnace body, 2... Container, 3...
...furnace top, 4...quartz glass plate, 5...
... Burner, 6... Fused silica grains, 7...
...Raw material, 8...Movement device. 1 certified ticket, 2 boxed tickets, 3 different types, 5 different types of enemy grass

Claims (1)

[Claims] 1. When producing fused silica using a closed furnace in which raw material silicon dioxide is placed on a movable hearth and heated, a particle size of 1 to 25 mm is placed in a container made of a heat-resistant material provided on the hearth.
fused silica particles with a particle size of 30 to 100 mm
A method for producing fused silica, which comprises placing a silicon dioxide lump as a raw material and heating it to a temperature of at least 1750°C or higher while moving the lump. 2. In a closed furnace in which raw material silicon dioxide is placed on a movable hearth and heated from above, a container made of refractory material is placed on which molten silica grains are placed on the hearth and the raw material silicon dioxide chunks are placed on top of the molten silica particles. A fused silica production device characterized by being disposed on a hearth.