JPH0280384A - Heat insulating permanent lining brick - Google Patents

Abstract

PURPOSE:To form a heat insulating fireproof layer on permanent lining brick, to inhibit the radiation of heat from a molten metal vessel, etc., and to maintain the high temp. by adding river sand, etc., forming cavities on being vitrified at a calcining temp. to body material made of the same material as the brick. CONSTITUTION:A heat insulating fireproof layer is formed on permanent lining brick such as pagodite brick or aluminous brick by adding river sand, sea sand, etc., forming carvities or closed cells on being vitrified at a calcining temp. to body material made of the same material as the brick to obtain heat insulating permanent lining brick.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a permanently insulating brick for molten metal containers, etc.
In particular, it relates to a heat-insulating permanent brick with good heat-insulating properties.

Conventional technology Permanently tensioned bricks in molten metal containers are used to protect the iron skin from damage to the work bricks. ) Bricks are used. As the name suggests, permanent bricks are used for a fairly long period of time, from six months to a year.

Recent molten metal containers have begun to play the role of reaction vessels for preliminary treatment of hot metal, secondary refining of molten steel, etc., rather than simply serving as containers for transporting molten metal. As a result, the time the molten metal remains in the molten metal container becomes longer, and
The temperature drop is increasing. Therefore, various measures are taken to compensate for the temperature, such as blowing gaseous acid (gaseous oxygen) into the hot metal and raising the tapping temperature of the converter. However, because conventional work bricks have poor durability, carbon-containing refractories are often used, and their high thermal conductivity further increases the temperature drop, creating a vicious cycle. The best way to prevent this is to strengthen the insulation of the molten metal container.

Problems to be Solved by the Invention Means for reinforcing the insulation of the molten metal container are: - For boat fishing, install fire-resistant insulation bricks between the iron skin and the permanent bricks, or install fire-resistant glass fibers (so-called ceramic fibers). ) will be adopted.

However, insulating bricks deteriorate due to moisture in the mortar of the work bricks that are repeatedly applied during the use of the molten metal container, making it difficult to withstand long-term use, and ceramic fibers become crumbly when subjected to repeated compression pressure. This has disadvantages such as creating gaps and making the structure of the permanent brick unstable.

Means for Solving the Problems The present invention was developed in view of the above-mentioned problems, and in order to solve the above-mentioned problems, glass is added to the composition of clay made of the same material or almost the same material as that of permanent bricks at a firing temperature. The present invention provides a heat-insulating permanent brick characterized in that a heat-insulating fireproof layer is formed by adding additives such as river sand and sea sand that harden to form cavities or closed pores.

Function When the insulating permanent brick of the present invention is used in a molten metal container, etc., the heat insulation property is enhanced by the insulating fireproof layer having cavities or closed pores, and heat radiation from the molten metal container, etc. to the outside can be suppressed as much as possible, and high temperatures can be maintained. . In particular, the insulation fireproof layer
Additives such as river sand and sea sand are added to the mixture of clay made of the same material or almost the same material as conventional permanent bricks, so it is easy to mix, easy to manufacture without segregation, and has the required strength. It is also possible to maintain corrosion resistance.

Example The present invention will be explained below based on examples.

Figures 1 and 2 show an embodiment of the present invention, which is laminated to a permanent brick. The heat-insulating permanent brick 1 is formed by laminating a heat-insulating refractory layer 3 on one side (preferably the outside) of the permanent brick 2, as shown in Fig. 1, to maintain the corrosion resistance and strength of the permanent brick 2. At the same time, it has insulation properties. The permanent brick 2 is made of a waxy permanent brick, and is made of the same material as the conventional brick. The heat-insulating refractory layer 3 is made of the same material or approximately the same material composition as the wax stone permanent brick 2, mixed with a predetermined inorganic additive 4, and vitrified during firing to form wax stone coarse particles 5 as shown in Fig. 2. , the bricks penetrate between the matrix parts 6 to form closed pores 7.

The raw material for permanent brick material contains a large amount of SiO2, as well as Al□O1 and a small amount of alkali (R,0).
It also contains the main minerals of quartz and pyrophyllite. and generally 1300°C
Softening begins at around 1400"C, vitrification begins at around 1400"C, and expansion occurs due to the so-called bloating phenomenon.When making waxite bricks, the heating temperature starts at around 1200"C, just before softening begins.
It is fired and sintered at 1250°C.

Stow-Alt that just vitrifies at this firing temperature
When using OS-based raw materials, the glass produced has a similar composition to the waxite raw material, so even if the produced glass phase reacts with the bricks, it will only become highly refractory, and the effect on the bricks as a whole will be minor. . As a raw material, as a result of testing various inorganic materials that are the same as those of permanent bricks or have a part of the composition of bricks, sand was found to have the best properties for pyrolithic bricks. Met.

The sand can be easily produced by hand, such as river sand, sea sand, or finely crushed stone. However, these sands have slightly different compositions and vitrification temperatures depending on where they are produced.

In particular, finely crushed crushed stone with a high iron content has a low vitrification temperature and permeates throughout the bricks, so when using sand, it is necessary to ensure that the sand remains in the manufacturing conditions. River sand and sea sand can be used with almost the same particle size, but it is preferable that the glass phase film that reacts with the bricks be as thin as possible, so it is desirable that the particle size is 0.5 or less. Sand additives can be mixed in the same way as in normal work without causing segregation, which makes it difficult to mix the clay due to the difference in specific gravity like in styrofoam balls, and it can be easily dispersed evenly after firing. It is possible to form a heat insulating refractory layer having closed pores and cavities.

Even when closed pores and cavities were formed by firing, the material did not expand, did not damage the brick base, and was preferable as a brick shape.

Other Embodiments FIGS. 3 and 4 show other embodiments of the present invention, in which the above-mentioned heat-insulating refractory layer 3 is laminated between the permanent bricks 2.

Structures related to two-layer bricks made of different materials have been known for a long time, such as a two-layer structure of zircon prize and waxy stone, and a two-layer structure of magnesia prize and a heat-insulating layer of magnesia decafoamed alumina. However, in this example, since the structure is a laminate of a fireproof layer made of the same material and a heat insulating fireproof layer having heat insulating properties, Figs.
Even when formed into a sandwich or honeycomb structure as shown in the figure, cracks do not occur at the layer boundaries during firing, and the brick as a whole maintains the same strength as a brick with only a refractory layer.

Table 1 compares the strength of the highly heat-insulating permanent tension bricks 1 of the laminated structure shown in FIGS. 1, 3, and 4 of the present invention.

Table 2 Comparison ratio table Table 1 Comparison table of compressive strength (kg/cii) Results of compressive strength test when pressurized in the molding direction, Sand inch structure shown in Figures 3 and 4 is preferable because it has strong strength.

Table 2 shows the blending ratio of various examples of the present invention with conventional products, and Table 3 compares the properties of these.

As can be seen from Table 3, the highly insulating permanent brick of the present invention has a low thermal conductivity, a low coefficient of linear expansion, and good corrosion resistance and spalling resistance.

Judging from these surface conditions and properties, the particle size is 0.5~
It can be judged that Example No. 3, in which 0.5% of river sand of 0.1 yen was mixed, is good for practical use.

Table 3 Properties Comparison Table Usage Example Regarding the third example above, the heat insulating fireproof layer is 3011
Permanent tension bricks with a permanent tension layer of 20 mm on the inner surface and 15 layers on the outer surface, laminated to a total thickness of 65 mm, were tested in an actual melting pot furnace.

As a result, the temperature drop of molten steel, including various steel types, from the time of tapping in the converter to the representative time of continuous casting was reduced by about 2°C, and the heat insulation of the molten metal container was strengthened.

In the above embodiment, the material of the permanent brick is described as a wax brick, but the present invention can be similarly applied to an alumina brick or the like.

In the above embodiments, a preferred embodiment in which the heat insulating refractory layer is integrally laminated on the permanent brick has been described, but it is also possible to use the heat insulating fire resistant layer and the permanent brick in a stacked manner.
Furthermore, the heat-insulating fire-resistant layer can be used alone as a fire-resistant wall of heat-insulating permanent bricks with a predetermined thickness.

Further, the inorganic additive in the heat insulating fireproof layer may be one that forms closed pores as described above, or one that forms equivalent cavities.

Effects of the Invention As described above, in the present invention, the heat insulation properties of hot water containers etc. can be improved by increasing the heat insulation properties by using the heat insulating fireproof layer which is vitrified by sintering and has closed pores and cavities, and the heat insulation properties of hot water containers etc. can be improved. In addition to being able to deal with the problem of prolonged residence time, it is also possible to prevent a vicious cycle in which the temperature drop becomes even greater even when a workpiece brick with high thermal conductivity is used.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted side view of one embodiment of the present invention, and FIG.
The figure is an enlarged view of the structure of the heat insulating and fireproof layer portion of the same as above, and FIGS. 3 and 4 are side views, with parts omitted, of other embodiments of the same as above. l...Highly heat insulating permanent brick, 2...Permanent tension brick, 3...Insulating fireproof layer, 4...Additive material, 7...
Closed stomata. Applicant: Kawasaki Rozai Co., Ltd. Agent Patent Attorney: Kuni Morimoto Akisunya:

Claims (1)

[Claims] (1) A heat-insulating fireproof layer is formed by adding additives such as river sand or sea sand that vitrify at firing temperatures to form cavities or closed pores to a clay mixture made of the same material or approximately the same material as permanent bricks. A permanent insulation brick characterized by: