JPH04329814A - Molten metal vessel - Google Patents

Abstract

PURPOSE:To efficiently transfer heat and to improve service life of a refractory by welding cooling pipes on an iron shell and cooling the lining refractory. CONSTITUTION:The cooling pipes 2 are welded on outer surface of the iron shell 1, and by flowing cooling medium 3 of water, gas, etc., therethrough, the iron shell is cooled. Onto inner surface of the iron shell, the lining refractory 4 is enclosed with an iron plate 5 and fixed to the iron shell 1. The lining refractory is used as brick or monolithic refractory having heat conductivity of >=5.0kcal/m.hr. deg.C at 800 deg.C and working thickness is made to be <=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 vessel having a refractory lining for use in refining furnaces such as converters and electric furnaces.

0002

BACKGROUND OF THE INVENTION A conventional technique for cooling the refractory lining of a molten metal container is disclosed, for example, in Japanese Patent Laid-Open No. 57-67110.
There is a method of cooling using mist or the like. However, in normal molten metal containers, there is an air gap between the shell and the refractory, and the refractory itself provides heat resistance, so even if the shell is cooled, the temperature of the operating surface of the refractory lining will only decrease slightly. There was a problem.

Regarding the prevention of air gaps, a technique for press-fitting monolithic refractories into the gaps was disclosed in Japanese Patent Laid-Open No. 52-3612.
Although disclosed in Publication No. 1, the gap is not necessarily continuous over the entire surface of the molten metal container, and for this reason, there is a problem in that it is difficult to press fit the monolithic refractory into the entire gap. Further, the thermal resistance due to the refractory itself can be reduced by reducing the thickness of the refractory, but in that case, the life of the molten metal container, which is determined by the rate of wear of the refractory, is short and becomes uneconomical, resulting in poor productivity.

0004

[Problems to be Solved by the Invention] The present invention provides a molten metal container having a structure capable of lowering the temperature of the working surface of the refractory lining without creating an air gap between the shell and the refractory in the molten metal container. The purpose is to provide a container.

[0005]

[Means for Solving the Problems] That is, the present invention provides water cooling,
In a molten metal container having an outer surface of a shell that is cooled by air or mist, at least two sides of the refractory layer in a direction perpendicular to the shell are covered with metal, and the metal part is fixed to the inner surface of the shell. It is a molten metal container characterized by a refractory lining, preferably made of brick or a monolithic refractory having a thermal conductivity of 5.0 kcal/m・hr・℃ or more at 800°C, or a refractory lining. This is a molten metal container made of a refractory material whose layers have a thermal conductivity of less than 5.0 kcal/m·hr·°C and has an operating thickness of 200 mm or less.

[0006]

[Operation] The operation of the method of the present invention will be explained based on FIG. A cooling pipe 2 is welded to the outer surface of the steel shell 1, and water, water, etc.
The iron skin 1 and the lining refractory 4 are cooled by the flow of a cooling medium 3 such as gas. The cooling method is not limited to any other method as long as it cools the lining refractory through the steel shell, such as by spraying a cooling medium onto the steel shell.

[0007] The inner surface of the steel shell is a furnace material in which at least two sides of the refractory layer in a direction perpendicular to the steel shell are covered with metal, and a metal portion is fixed to the inner surface of the steel shell. As for the fixing method at this time, there is no need to create an air gap during operation, and if the welding method is used, spot welding can sufficiently satisfy the function, so there is no need to fillet weld the entire circumference, but other fixing methods can be used. For example, a high-temperature, high-strength organic adhesive may be used. Further, the material of the metal enclosing the refractory may be any metal with high thermal conductivity, and iron plates are generally used. Furthermore, if this metal is extremely thick, there is an increased risk of steel leakage from this metal, so based on experience with joint iron plates in conventional furnace construction methods, it is desirable that the thickness be around 0.6 to 1.8 mm. .

Next, the apparent thermal conductivity λ by the method of the present invention and the conventional method was evaluated by measuring the temperature inside the refractory and the temperature of the cooling water. Note that the apparent thermal conductivity λ is (
1) It was determined from the formula. λ=q・Δx/(T1 −T2)...(1) Here, q=Amount of heat removed from the temperature difference between the inlet and outlet sides of the cooling water T1 -T2=Two points in the thickness direction of the refractory layer temperature difference Δ
The relationship between the average temperature of the refractory and the apparent thermal conductivity λ determined by the distance between x=2 temperature measurement points (1) is shown in FIG. 2, comparing the present invention and the conventional case. In the case of the present invention, a refractory wrapped on all four sides with a metal case is installed, and the apparent thermal conductivity of the refractory is improved by about 2 to 3 times compared to conventional ones, reducing the thermal resistance of the refractory itself. It became clear that By attaching the metal in this way, the thermal resistance of the refractory itself is reduced without creating an air gap, but the absolute value is larger for the refractory, so the temperature near the working surface of the refractory is lower than that of the refractory layer. It is thought that it is determined by thermal resistance.

Next, FIG. 3 shows the relationship between the thermal conductivity of the refractory and the temperature near the operating surface (10 to 20 mm inside from the operating surface). Thermal conductivity of refractories: 5.0 kcal/m at 800°C
By setting the temperature to hr・℃ or more, the temperature near the operating surface can be reduced to 1
, 500°C or less. Also,
As shown in Figure 4, the thermal conductivity is 5.0k at 800℃
It has become clear that when using a refractory with a temperature lower than cal/m·hr·°C, the temperature near the working surface can be reduced to 1500°C or less by setting the working thickness of the refractory to 200 mm or less.

[0010] In the present invention, as a method of wrapping the surface of the refractory layer in a direction perpendicular to the iron skin with metal, there is a method of enclosing the refractory in a metal case in advance, or a method of enclosing the refractory in a molten metal container. During construction, there is a method in which metal is sandwiched between refractories to secure them in place.

[0011]

[Example] Table 1 shows an example in which the present invention was applied to the throat constriction of a 5T converter. In Example 1, unfired MgO-C bricks (thermal conductivity at 800°C of 15 kcal/m・hr・°C) with a thickness of 300 mm and surrounded by two 1.2 mm metal cases were used as the lining refractory. did. Also,
In Example 2, the lining refractory was made of low carbon unfired MgO-C bricks (with a thermal conductivity of 5.5 kcal/m at 800°C) having a thickness of 300 mm and surrounded by four 1.2 mm metal cases. hr・℃) was constructed. Furthermore, in Example 3, the thickness of the lining refractory was 1
50mm, Al2O3-SiC castable 1
．． Precast product poured into a 2mm metal case (thermal conductivity at 800℃ is 3.5kcal/m・hr)
・°C) was constructed in the same way as bricks. The material of the metal case was made of iron plate, which is the same as in Examples 1 to 3, and the fixing method was spot welding.

In Comparative Examples 1 and 2, Examples 1 and 2
It uses the same bricks and does not use a metal case. In both Examples 1 to 3 and Comparative Examples 1 and 2, cooling was performed by flowing cooling water at a rate of 250 l/min into a cooling pipe welded to the outer surface of the steel shell, and the top and bottom oxygen was blown under conditions that caused secondary combustion due to top blown oxygen. We performed blowing. As is clear from Table 1, the temperature near the working surface of the refractory after 2 hours of blowing was approximately 200°C in Examples 1 to 3, compared to Comparative Examples 1 and 2. It is clear that the cooling effect is greater in the embodiment according to the present invention.

[0013] Furthermore, the thickness of the bricks was measured by a laser beam method before and after blowing, and the wear index shown in Table 1 was calculated from the amount of wear. The amount of wear and tear in the examples according to the present invention is 1/2 to 1/3 of that in the comparative example, which is 2 to 3 times the number of lifetimes.

[0014]

[Table 1]

[0015]

Effects of the Invention: When cooling the refractory lining of a molten metal container through the steel shell, according to the present invention, in which the metal is fixed to the steel shell, the thermal resistance due to the gap between the steel shell and the refractory is reduced, thereby reducing the heat resistance inside the container. We were able to effectively remove the heat from the This lowered the temperature of the refractory lining and significantly increased the lifespan of the refractory lining.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a brick showing one embodiment of the present invention.

FIG. 2 is a comparison diagram of apparent thermal conductivity with and without a metal case.

FIG. 3 is a diagram showing the relationship between the thermal conductivity of a refractory and the temperature near the operating surface of the refractory.

FIG. 4 is a diagram showing the relationship between the thickness of the refractory layer and the temperature near the operating surface of the refractory.

[Explanation of symbols]

1 Iron skin 2 Cooling pipe 3 Cooling medium 4 Refractories 5 Metal

Claims (3)

[Claims] Claim 1: In a molten metal container having an outer surface of a shell that is water-cooled, air-cooled, or mist-cooled, at least two surfaces of the refractory layer in a direction perpendicular to the shell are covered with metal, and the inner surface of the steel shell is A molten metal container characterized by a fixed metal part. 2. The molten metal according to claim 1, wherein the lining refractory layer is made of brick or a monolithic refractory having a thermal conductivity of 5.0 kcal/m·hr·°C or more at 800°C. container. [Claim 3] The thermal conductivity of the lining refractory layer is 5.0k.
The molten metal container according to claim 1, characterized in that it is made of a refractory of less than cal/m·hr·° C. and has an operating thickness of 200 mm or less.