JPH05312485A - Metallurgical vessel bottom gas blowing device - Google Patents

Abstract

PURPOSE:To prolong the life of a hearth by ensuring the thickness of a material of a furnace bottom even by blowing gas from the bottom. CONSTITUTION:A metallurgical vessel introduces agitating gas from a furnace bottom and guides it into molten metal through a hearth 1 in which a permanent lining 3 made of refractory bricks and consumable lining 4 made of indeterminate refractory are disposed. A spiral gas blowing tube 20 is disposed directly above a furnace bottom plate 2, a pocket is formed at a lower side of the plate 2, and the spiral gas blowing tube is disposed in the pocket.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom metal gas injection device for a metallurgical vessel for introducing a stirring gas into a molten metal through a bottom and a hearth.

[0002]

2. Description of the Related Art In a metallurgical vessel, for example, an electric furnace, when refining the molten steel in the vessel, it has been a conventional practice to stir the molten steel with a gas in order to accelerate a metallurgical reaction. In steelmaking by an electric furnace, it is well known that the molten steel is stirred by introducing an inert gas into the molten steel from a gas injection port in the hearth or the bottom of the furnace to remove impurities and promote metallurgical reaction.

As a gas blowing device, for example, Japanese Utility Model Publication No. 1-29233 discloses a method of using a gas blowing plug extending through a permanent lining and a consumable lining. However, since this plug is directly damaged by the molten metal in the furnace, it has a short life compared with the permanent lining.

Further, in the metallurgical container disclosed in Japanese Patent Laid-Open No. 196494/1989, the stirring gas can be introduced without directly damaging the gas blowing device by the molten metal in the furnace. This will be described with reference to FIGS.

In FIG. 3, a densely assembled permanent refractory brick lining 3 is stretched on a bottom plate 2, and a furnace bottom expendable lining 4 of an irregular shaped refractory material is provided thereon. A furnace bottom brick 6 having an opening 6a is inserted in the permanent lining 3, and a furnace bottom brick 7 having no opening is arranged around the furnace bottom brick 6 to support the furnace bottom brick 6. Further, the thin tube 5 branched from the supply pipe 9 through the opening 2a and the opening 6a extends into the furnace and is sealed by the seal 5a, and the periphery is filled with mortar. Then, the deflection plate 8 is arranged in the consumable lining 4 above the furnace bottom brick 6, and the stirring gas passes from the supply pipe 9 through the thin tube 5 and is diffused by the deflection plate 8 so that the consumable lining material 4 and the sintered layer 14 are diffused. Through which the gas bubbles are distributed over a wide range and the stirring of the molten metal is effectively performed.

Further, as shown in FIG. 4, the conical plug 1
It has also been proposed that 5 is put in a fireproof seating member 16 with a slight gap, held by a flange 17 fixed to the furnace bottom plate, and gas is introduced from a gas supply pipe 9a.

[0007]

By the way, in general, peeling occurs in the sintered layer portion on the surface of the hearth with the infiltration of molten steel and the progress of sintering. The thickness of the furnace material including the permanent lining of the bottom of the metallurgical container is usually about 600 mm, and if the deflecting plate is provided during the consumable lining as in the conventional example, the thickness of the furnace material to the deflecting plate becomes thin, If the peeling of the sintered layer portion is repeated, the skin is easily separated at the deflecting plate portion, which shortens the life and increases the repair frequency. In particular, when the deflector plate is made of metal, with the peeling of the sintered layer part,
The metal deflection plate is further heated to generate thermal strain, which causes cracks in the irregular refractory material forming the hearth, and the molten metal enters the cracks, which shortens the life of the hearth. Further, when the deflector plate is made of ceramic, cracks are likely to occur during the construction of an irregular refractory material, and the deflector plate is not easy to manufacture.

The present invention has been made to solve the above problems. The gas blowing device is not directly damaged by the molten metal in the metallurgical container, is easy to manufacture, and the gas is blown from the bottom of the furnace. Secure the furnace material thickness of
An object of the present invention is to provide a metallurgical container furnace bottom gas blowing device capable of extending the life of the hearth.

[0009]

According to the present invention, a stirring gas is introduced from the bottom of a furnace, and a permanent lining made of refractory bricks and a consumable lining made of amorphous refractory are placed in a molten metal through a hearth. In the metallurgical container to be guided, a gas blowing pipe is arranged directly above the furnace bottom plate. Further, the present invention is a metallurgical container, which introduces a stirring gas from the bottom of the furnace, and introduces it into the molten metal through the hearth where the permanent lining made of refractory bricks and the consumable lining made of amorphous refractory are arranged. A pocket is formed on the lower side of the furnace bottom plate, and a gas blowing pipe is arranged in the pocket. Furthermore, the present invention is characterized in that the gas blowing pipe comprises a spiral pipe in which a plurality of gas ejection ports are formed. Further, the present invention is characterized in that the circumference of the spiral pipe is blocked with a breathable amorphous refractory.

[0010]

According to the present invention, for example, a circular pipe, a polygonal pipe, a spiral pipe or the like having a plurality of gas jets formed on the bottom plate is directly arranged at one or a plurality of positions. In this case, the stirring gas can be distributed over the range of the spiral diameter, and the thickness of the furnace material on the spiral pipe can be secured. Further, by forming a pocket on the lower side of the furnace bottom plate and arranging spiral pipes at one or a plurality of locations in this pocket, the thickness of the furnace material on the pipe can be secured in the same manner. It is possible to extend the life of the floor.

[0011]

EXAMPLES The features of the present invention will be specifically described below based on examples. FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. In the figure, 1 is a hearth floor, 2 is a bottom plate, 3 is a permanent lining, 4 is a consumable lining, 20 is a gas supply pipe, 21 is a spiral pipe, and 21a is a gas ejection port. In the present embodiment, as shown in FIG. 1 (a), a region where the permanent lining 3 forming the hearth is not provided is formed, and the spiral pipe 21 is arranged directly above the hearth bottom plate 1 in this region, A consumable lining 4 is formed by filling a ramming material (stamp material) on it. The thickness of the permanent lining 3 is 200 mm
The thickness of the consumable lining 4 is about 400 mm, and the hearth thickness is 600 as the distance from the pipe 21 to the hearth surface.
mm can be secured as it is. As shown in FIG. 1B, the spiral pipe 21 has one or several turns having a predetermined diameter, and is provided with a plurality of gas ejection ports 21a. The inner diameter of this gas ejection port 21a is 1 to 6
mm is desirable. The ratio of the spiral diameter of the pipe to the inner diameter of the gas ejection port is preferably in the range of 50: 1 to 200: 1. In this case, the pipe inner diameter d is 5 to
It is 30 mm.

There are the following methods for installing the pipe. First, as shown in FIGS. 1 (a) and 2 (a), a spiral pipe is directly installed on the bottom plate of the furnace. In addition, as shown in FIG. 2 (b), the pipe is surrounded by an adiabatic heat insulating amorphous refractory 21, which is cured so as not to block the gas ejection port into a block. There is a construction method. This breathable heat-insulating amorphous refractory can further enhance the heat-insulating effect with the furnace heat, and prevents the occurrence of thermal strain in the pipe. In this case, it is desirable that the ratio of the thickness A of the breathable adiabatic amorphous refractory to the outer diameter D of the pipe is within the range of 1: 1 to 3: 1. This pipe may be installed at one or more locations on the bottom of the furnace.

As described above, since the thickness of the furnace material on the spiral pipe 21 for ejecting gas can be sufficiently secured, even if the sintered layer portion is peeled off, it is easy to separate the pipe portion. It does not occur and the life can be extended. Also,
By appropriately selecting the spiral diameter of the pipe, the gas bubbles can be distributed over a wide range with one pipe, and the molten metal can be effectively stirred. In addition, the pipe is easy to manufacture and can be installed easily. Furthermore,
Due to the wide distribution of the gas bubbles, the refractory with irregular shape was strongly cooled, which doubled the life of the hearth.

FIG. 2 is a diagram showing another embodiment of the present invention. In the present embodiment, as shown in FIG. 2A, a pocket 30 is provided in the lower part of the furnace bottom plate, and a pipe 21 is arranged in the pocket. The pocket 30 is formed by attaching a plate 32 having an opening to a tip flange portion of a hollow member 31 hanging from a furnace bottom plate, and arranging a plate 33 inside to support the pipe 21. The hollow member 31 may be welded to the furnace bottom plate 2 or may be formed so as to project the furnace bottom plate downward. The plate 32 is bolted to the hanging furnace bottom plate 2 and packed, and as shown in FIG. 2B, the pipe 20 is fixed to the plate 33 by welding 35 or the like, and the plate 33 is fixed to the plate 32 with the bolt 34. Fix and pack.

By arranging the pipe in the pocket installed below the furnace bottom plate as described above, the thickness of the furnace material on the pipe can be further increased, and the pipe is unitized with the plate 33. , Can be installed and replaced easily.

In the above embodiment, the case where the spiral pipe is used as the gas blowing pipe has been described, but the present invention is not limited to the spiral pipe, and the pipe may have any shape such as circular, triangular diameter, square or polygonal shape. However, these may be appropriately selected as needed.

Further, the gas blowing device of the present invention is not only suitable for the bottom of an electric furnace, but also has a bottom portion including a permanent lining of refractory bricks and a consumable lining of irregular-shaped refractory (metallurgical vessel (ladle or rolling). Suitable for furnaces, etc.

[0018]

As described above, according to the present invention, the thickness of the furnace material of the furnace bottom can be secured by blowing gas from the furnace bottom, the life of the hearth can be extended, and the spiral pipe can be achieved. The stirring gas can be distributed over a wide range of diameter. Further, in the case of the electric furnace, the stirring effect of the molten steel is improved, and by introducing the stirring gas into the molten metal in a wide area, it is possible to stir the molten steel while maintaining the arc uniformly and quietly. ..

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of another embodiment of the present invention.

FIG. 3 is a diagram showing a conventional example of a furnace bottom gas blowing device.

FIG. 4 is a diagram showing a conventional example of a furnace bottom gas blowing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hearth floor, 2 ... Furnace bottom plate, 3 ... Permanent lining, 4 ... Consumable lining, 20 ... Gas supply pipe, 21 ... Spiral pipe, 21a ... Gas ejection port, 30 ... Pocket, 31 Hollow member, 32, 33 ... plate.

Claims (4)

[Claims] 1. A metallurgical vessel in which a stirring gas is introduced from the bottom of a furnace and is introduced into a molten metal through a hearth in which a permanent lining made of refractory bricks and a consumable lining made of amorphous refractory are arranged. A gas injection device for the bottom of a metallurgical vessel, characterized in that a gas injection pipe is arranged directly above the bottom plate. 2. A metallurgical vessel in which a stirring gas is introduced from the bottom of a furnace and is introduced into a molten metal through a hearth in which a permanent lining made of refractory bricks and a consumable lining made of amorphous refractory are arranged. A metal injection vessel furnace bottom gas blowing device, characterized in that a pocket is formed below a furnace bottom plate and a gas blowing pipe is arranged in the pocket. 3. The method according to claim 1 or 2, wherein
A gas injection device for a bottom of a metallurgical vessel, wherein the gas injection pipe is composed of a spiral pipe in which a plurality of gas ejection ports are formed. 4. The apparatus for injecting gas into a bottom of a metallurgical vessel according to claim 3, wherein the spiral vip is surrounded by a breathable amorphous refractory.