JPH059542A - Molten metal vessel - Google Patents

Abstract

PURPOSE:To improve heat dissipation efficiency from a lining refractory and to improve this service life by fixing metal-made fins on the inner face of an iron shell in a molten metal vessel for refining furnace and further, forming the lining refractory layer with brick having the specific linear expansion coefficient. CONSTITUTION:On the outer face of the iron shell 1 in the molten metal vessel, cooling pipes 2 are arranged, and by allowing a cooling medium 3 to flow, water-cooling, air-cooling or mist-cooling is executed. On the inner face of this iron shell 1, the metal-made fins 4 are fixed. The bricks 5 are laid among these fins 4 or monolithic refractory is poured to set the lining refractory layer. At this time, the linear expansion coefficient of the above brick 5 or (linear expansion coefficient + {linear changing rate (%) at 500 deg.C}/{500 X 100}) of the monolithic refractory is made to be >=2X10<-6> (1/ deg.C). Further, it is desirable that fin 4 interval (d) <= refractory thickness LX0.5, fin 4 length 1>=0.5L and >=5.0kcal/m hr deg.C thermal conductivity of lining refractory layer at 800 deg.C, or <5.0kcal/m hr deg.C thermal conductivity and L<=200mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal container having a refractory material lined therein for use in a refining furnace such as a converter or an electric furnace.

[0002]

2. Description of the Related Art A conventional technique for cooling a refractory lining a molten metal container is to cool the outer surface of an iron skin with water, gas, mist, etc., as disclosed in, for example, JP-A-57-67110. There is a way to do it. However, in an ordinary molten metal container, the air gap that occurs between the iron shell and the refractory and the refractory itself provides thermal resistance, so even if the iron shell is cooled, the temperature drop on the lining refractory operating surface is small. There was a problem.

Regarding air gap prevention, a technique of press-fitting an irregular shaped refractory into the gap is disclosed in JP-A-52-36121, but the gap is not always continuous over the entire surface of the molten metal container. Therefore, there is a problem that it is difficult to press-fit the irregular refractory into the entire gap. Also, the thermal resistance due to the refractory itself can be reduced by reducing the refractory thickness, but in that case, the life of the molten metal container, which is determined by the wear rate of the refractory, will be shortened, which will hinder operation. .

[0004]

When the temperature of the refractory is lowered by cooling the outer surface of the iron shell, the air gap generated between the iron shell and the refractory and the refractory itself become a large thermal resistance from the inside of the furnace. Since there is a problem in the conventional countermeasure technology for preventing the heat removal of steel, the present invention has a structure having a structure capable of lowering the temperature of the lining refractory even if an air gap occurs between the iron shell and the refractory. The purpose is to propose a metal container.

[0005]

That is, according to the present invention, in a molten metal container having an outer surface of an iron shell that is water-cooled, air-cooled or mist-cooled, metal fins are fixed to the inner surface of the iron shell, and a refractory layer lined inside is formed. Linear expansion coefficient is 2 × 10 ^-6 (1 / ° C)
It is made of the above bricks, or the refractory layer lined is [linear expansion coefficient + {linear change rate (%) at 500 ° C) / {500
X100}] is an amorphous refractory having a size of 2 × 10 ^-6 (1 / ° C) or more, and it is desirable that the space between the fins is lined with the thickness of the refractory layer. 0.5 times or less, and the length of the fin to the thickness of the refractory layer lining
0.5 times or more, or the inner refractory layer is made of bricks or amorphous refractory having a thermal conductivity of 5.0 kcal / m · hr · ° C or higher at 800 ° C, or the inner refractory layer has thermal conductivity Is a refractory material with a temperature of less than 5.0 kcal / m · hr · ° C and a thickness of 200 mm or less.

[0006]

[Operation] An embodiment of the method of the present invention is shown in FIGS. A cooling pipe 2 is welded to the outer surface of the iron shell 1, and a cooling medium such as water or gas flows therein to cool the iron shell and the refractory lining. The cooling method is not limited to this method as long as it is a method of cooling the lining refractory through the iron shell, such as a method of spraying a cooling medium on the iron shell.

Fins 4 are fixed to the inner surface of the iron skin by welding or the like, and bricks 5 are piled up between the fins 4 (see FIG. 1) or an irregular refractory material 6 is poured (FIG. 2). reference). The fin material may be a metal having a high thermal conductivity, and most commonly, iron or copper can be considered. Usually, an air gap is created between the iron skin 1 and the refractory lining such as the brick 5 and the irregular shaped refractory 6, which serves as heat resistance and prevents heat removal from the inside of the container. In the present invention, the fins 4 having high thermal conductivity are embedded inside the refractory lining, and the heat inside the container can be effectively released to the outside of the container through the fins.

In order to increase the temperature decrease of the refractory material, it is necessary to improve the adhesion between the fin and the lining refractory material. For that purpose, the coefficient of linear expansion of the lining refractory material is an important index. Become. In a molten metal container lined with bricks, the relationship between the linear expansion coefficient of the bricks and the temperature near the brick working surface is shown in FIG. The vicinity of the working surface means a position within 10 mm from the working surface. When the coefficient of linear expansion is 2 × 10 ^-6 (1 / ° C) or more compared to the case without fins, the temperature near the operating surface is 20
Decrease by 0 ° C. This is because the brick expands as the temperature rises, and the fin and the brick come into contact with each other, but by using the brick having a linear expansion coefficient of 2 × 10 ^-6 (1 / ° C) or more, the fin and the brick It is considered that this is because the close contact between the two becomes almost complete.

When an amorphous refractory material is lined, moisture is released by the drying after pouring and shrinks. Therefore, contact with fins cannot be completed unless the coefficient of linear expansion is larger than that of brick. In a molten metal container lined with an irregular refractory, the relationship between the linear expansion coefficient of the irregular refractory + linear change rate at 500 ℃ (%) / 500 × 100 and the temperature near the operating surface is shown in Fig. 10.
Shown in. Compared to the case without fins, when the linear expansion coefficient + linear change rate (%) at 500 ° C / 500 × 100 is 2 × 10 ^-6 (1 / ° C) or more, the temperature near the operating surface is
200 ° C lower. In the case of amorphous refractories, it can be said that the linear expansion coefficient must be large enough to compensate for the shrinkage during drying. Further, some amorphous refractory materials have residual expansivity, and in this case, the linear change rate has a positive value. In this case, as in the case of shrinkage, the linear expansion coefficient + {linear change rate (%) at 500 ° C} / {500 × 100} is set to 2 × 10 ^-6 (1 / ° C) or more The temperature near the surface can be reduced. The shrinkage was represented by the linear change rate at 500 ° C because the temperature of the part of the refractory in use that comes into contact with the fins is 100 to 900 ° C.

From the above, the coefficient of linear expansion is 2 × 10.
Brick of ^-6 (1 / ℃) or more, or linear expansion coefficient + {500
Line change rate (%) / (500 × 100)} is 2 × 10
^-6 (1 / ° C) or more of irregular shaped refractory can be lined
It has been found to be extremely effective for effective heat removal from the inside of the container. Here, the present inventors have found that the fin spacing d and the fin length l are important in order to increase the temperature decrease amount of the refractory material. If the fin spacing is large, or if the fin length is short, the effect of the gap between the iron skin and the refractory is greater than the effect of heat removal through the fin, and the fin effect is small. Become. FIG. 3 shows the relationship between the ratio d / L of the fin spacing d to the refractory layer thickness L and the temperature near the refractory working surface. If the fin spacing is less than 0.5 times the refractory layer thickness, the refractory temperature will be 100 ° C or more lower than when there is no fin.

FIG. 4 shows the relationship between the ratio 1 / L of the length l of the fin and the thickness L of the refractory layer and the temperature near the refractory working surface. If the fin length is 0.5 times the refractory layer thickness or more, the refractory temperature will be 100 ℃ or more lower than that without fins. By the way, FIG. 5 shows the thermal resistance R ₁ in the air gap with and without the fin, which is obtained from the temperature measurement results of the refractory, the iron shell and the cooling water by the equation ₁ .

R ₁ = (T ₁ −T ₂ ) / q (Equation 1) where T ₁ is the temperature of the refractory side of the refractory, T ₂ is the temperature of the refractory side of the refractory, and q is the input / output of cooling water. It is the amount of heat removed from the side temperature difference. It has been clarified that the thermal resistance in the air gap is reduced by one to two orders of magnitude by attaching the fins as compared with the case without the fins.

Next, FIG. 6 shows the apparent thermal conductivity λ of the refractory layer obtained from Equation 2. λ = q · Δx / (T ₃ −T ₄ ) ... (Equation 2) where T ₃ and T ₄ are temperatures at two points in the thickness direction of the refractory layer,
Δx: The distance between two temperature measurement points. By attaching the fins, it was revealed that the apparent thermal conductivity of the refractory layer was improved to 2-3 times, and the thermal resistance of the refractory itself was reduced.

When the fins are attached as described above, the thermal resistances of the air gap and the refractory itself are small,
Since the absolute value of the refractory is usually larger than that of the refractory, the temperature near the refractory operating surface is considered to be determined by the thermal resistance of the refractory layer. Next, FIG. 7 shows the relationship between the thermal conductivity of the refractory material and the temperature near the operating surface. As mentioned above, the vicinity of the working surface means a position within 10 mm from the working surface.

The thermal conductivity of refractory is 5.0 kcal / m at 800 ° C.
・ By setting the temperature to be above hr ・ ° C, the temperature near the operating surface will be 15
It became clear that the temperature was below 00 ° C. Further, as shown in FIG. 8, when a refractory material having a thermal conductivity lower than 5.0 kcal / m · hr · ° C is used, the temperature in the vicinity of the working surface is controlled by setting the thickness of the refractory material to 200 mm or less. It became clear that the temperature was 1500 ° C or lower.

[0016]

EXAMPLES Table 1 shows an example in which the present invention is applied to a narrowing part of a furnace opening of a 5t converter. In Example 1, as the refractory lining, the thickness
300mm, the thermal conductivity at 800 ℃ 15kcal / m · hr · ℃, using a linear expansion coefficient of 10 × 10 ^-6 (1 / ℃) MgO-C brick,
A method of stacking bricks one by one between the fins was adopted. The fins were oriented in the same direction as the bricks were piled up, and the fins were attached in half steps in the circumferential direction.

In Example 2, as the refractory lining, 800
Thermal conductivity at ℃ 5.5kcal / m ・ hr ・ ℃, coefficient of linear expansion 2 ×
An amorphous refractory with a linear change rate of + 10% at 10 ^-6 (1 / ° C) and 500 ° C was poured into a thickness of 300 mm. In Example 3, the lining refractory has a thermal conductivity of 3.5 kcal / m at 800 ° C.
Irregular refractories with a hr · ° C, linear expansion coefficient of 8 × 10 ^-6 (1 / ° C) and a linear change rate at 500 ° C of -0.2% were cast into a thickness of 150 mm. The material of the fin was iron in Examples 1 to 3.

In Comparative Example 1, the same brick as in Example 1 was used, and no fin was used. In Comparative Example 2, the same amorphous refractory material as in Example 2 was used and no fin was used. In Comparative Example 3, magnesia dolomite brick having a thermal conductivity of 3.5 kcal / m · hr · ° C at 800 ° C was used, and fins were attached in the same manner as in Example 1. In Comparative Example 4, the thermal conductivity at 800 ° C is
Example 2 using an amorphous refractory material of 3.5 kcal / m · hr · ° C
The fins were attached in the same manner as in.

In each of Examples 1 to 3 and Comparative Examples 1 to 4, cooling water is cooled by flowing 250 l / min into a cooling pipe welded to the outer surface of the steel shell, and the upper bottom is conditioned under the condition that secondary combustion by top-blown oxygen occurs. Oxygen was blown. As is clear from Table 1, the temperature near the refractory operating surface 2 hours after the blowing was
Compared to Comparative Examples 1 to 4, in Examples 1 to 3, the temperature in the vicinity of the working surface of the refractory lining was reduced by about 200 ° C., and it is clear that the examples according to the present invention have a greater cooling effect.

[0020]

[Table 1]

Further, Table 2 shows an example in which the present invention is applied to a narrowed part of a furnace opening of a 5t converter. In Example 4, MgO- having a thickness of 200 mm and a linear expansion coefficient of 10 × 10 ⁻⁶ (1 / ° C.) was used as the refractory lining.
Using C bricks, the fin spacing is 80 mm and the fin length is
It was set to 150 mm, and bricks were stacked one by one between the fins. Match the direction of the fins with the direction of stacking bricks,
All circumferential fins are attached in the circumferential direction.

In Example 5, an amorphous refractory having a linear change rate of +0.2 (500 ° C.) and a linear expansion coefficient of 2 × 10 ⁻⁶ (1 / ° C.) was poured as a refractory lining with a thickness of 200 mm to form a fin. 50m interval
m, and the fin length was 140 mm. The direction of the fins was perpendicular to the iron shell, and the material of the fins was iron in Examples 4 and 5. In Comparative Example 5, the same brick as in Example 4 was used, and no fin was used.

In Comparative Example 6, the same amorphous refractory material as in Example 5 was used and no fin was used. Examples 4, 5 and Comparative Example 5,
250L of cooling water was welded to the outer surface of the iron 6
/ Min., And the upper bottom oxygen blowing was carried out under the condition that secondary combustion by top blowing oxygen occurs. Table 2 shows the temperatures near the refractory working surface 2 hours after the blowing operation.

As is clear from Table 2, the temperatures in the vicinity of the working surface of the lining refractory were reduced by about 200 ° C. in Examples 4 and 5 as compared with Comparative Examples 5 and 6, indicating that the Examples according to the present invention were better. However, it is clear that the cooling effect is large.

[0025]

[Table 2]

[0026]

EFFECTS OF THE INVENTION According to the present invention in which fins are fixed to the iron shell when cooling the refractory lining of the molten metal container through the iron shell, the thermal resistance due to the gap between the iron shell and the refractory becomes small and the inside of the container is reduced. It was possible to effectively remove the heat from. This lowered the temperature of the refractory lining and significantly improved the life of the refractory lining.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a brick of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the irregular refractory material of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between fin spacing / refractory layer thickness and temperature near the refractory operating surface.

FIG. 4 is a characteristic diagram showing the relationship between fin length / refractory layer thickness and temperature near the refractory operating surface.

FIG. 5 is a comparison diagram of thermal resistance of air gaps with and without fins.

FIG. 6 is a comparison diagram of apparent thermal conductivity with and without fins.

FIG. 7 is a diagram showing the relationship between the thermal conductivity of the refractory material and the temperature near the operating surface.

FIG. 8 is a diagram showing the relationship between the refractory layer thickness and the temperature in the vicinity of the operating surface.

FIG. 9 is a characteristic diagram showing a relationship between a temperature near a refractory working surface of a brick and a linear expansion coefficient.

FIG. 10 is a characteristic diagram showing a relationship between a temperature near a refractory operating surface and a linear expansion coefficient in an amorphous refractory.

[Explanation of symbols] 1 iron skin 2 cooling tubes 3 Cooling medium 4 metal fins 5 bricks 6 Irregular refractories 7 gap L Lined refractory layer thickness d Fin spacing l Fin length

Continued front page    (72) Inventor Mitsuo Saito             1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd.             Corporate Technology Research Division

Claims (4)

[Claims] 1. A molten metal container having an outer surface of an iron shell that is water-cooled, air-cooled or mist-cooled, a metal fin is fixed to the inner surface of the iron shell, and the lining refractory layer has a linear expansion coefficient of 2
Bricks with a ^{density of} × 10 ^-6 (1 / ° C) or more, or a coefficient of linear expansion of + (rate of linear change (%) at 500 ° C} / {500 × 100}) of 2 × 10 ^-6 (1 / ° C) or more A molten metal container characterized by being made of an amorphous refractory material. 2. The distance between the metal fins is 0.5 times or less the thickness of the lining refractory layer, and the length of the fins is 0.5 times or more the thickness of the lining refractory layer. The molten metal container described. 3. The refractory lining has a thermal conductivity at 800 ° C.
The molten metal container according to claim 1, wherein the molten metal container is made of brick or amorphous refractory having a temperature of 5.0 kcal / m · hr · ° C or higher. 4. The inner refractory layer has a thermal conductivity of 5.0 kcal /
The molten metal container according to claim 1, wherein the refractory material is less than m · hr · ° C and has a thickness of 200 mm or less.