JPH07216428A - Injection treatment method and immersion free board therefor - Google Patents

Abstract

PURPOSE:To improve productivity and to reduce cost by eliminating slopping from the clearance between an immersion free board covering over the molten steel or molten iron in a container and the container, settling the operational problem such as the equipment trouble of traveling inability of carrier, etc., resulting from slopping, increase of cleaning frequency and lowering of yield, etc. CONSTITUTION:A slopping preventing board 6 is protruded around the lower circumference of an immersion free board 1 and is brought into contact with a ladle 5, the clearance between the immersion free board 1 and the ladle 5 is plugged. By this method, a molten metal or molten iron 3 is prevented from splashing out of the ladle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is for refining by injecting a treating agent such as a dephosphorizing agent or a desulfurizing agent together with a carrier gas such as Ar or N ₂ gas into a molten steel or a molten steel or a molten pig iron in a molten pig iron container by a blowing lance. The present invention relates to an injection treatment method and a cup-shaped immersion freeboard used in the method.

[0002]

2. Description of the Related Art In order to reduce costs in refining processes and to cope with strict quality of steel grades, a treating agent such as a dephosphorizing agent or a desulfurizing agent is blown into a molten steel or hot metal with a carrier gas by a blowing lance to remove phosphorus, A so-called injection treatment of removing the sulfur by reacting with sulfur or the like is generally widely used.

In such an injection process, when the gas generated by the reaction or the carrier gas blown into the molten steel or the hot metal is bubbled through the molten steel or the hot metal to escape to the atmosphere, sloping occurs and the molten steel or the hot metal and the slag are removed from the container. If the container tends to overflow and then flows out from the container to the dolly and further spills onto the rail, problems such as being unable to run the dolly, cleaning the dolly, and lowering yield occur. In order to prevent this, conventionally, a cup-shaped dipping freeboard 1 as shown in FIG. 1 is used, and a part of the dipping freeboard 1 is molten steel or hot metal 3 with the blowing lance 2 placed downward. It is soaked in it and covered with molten steel or molten pig iron so that molten steel or molten pig iron 3 and slag 4 do not rise in the immersion freeboard and blow out from the container 5 by sloping during the injection process.

[0004]

If the immersion freeboard is mounted so as to be in close contact with the inner wall of the container, it becomes impossible to remove the immersion freeboard due to the attached metal, or the immersion freeboard is damaged when it is removed. Or, the inner wall of the container tends to be damaged. Therefore, as shown in FIG. 1, the immersion freeboard is conventionally mounted with a proper margin with the inner wall of the container, and therefore, depending on the blowing conditions, sloping between the container and the immersion freeboard is prevented. However, slag, molten steel or hot metal scatters out of the container, causing operational problems such as equipment troubles such as inability of the truck to run, increased truck cleaning frequency, and reduced yield.

The present invention is an injection treatment method capable of preventing sloping between a container and a dipping free board, and solving equipment troubles and operational problems caused by this, and a dipping free method used in the method. Intended to provide board.

[0006]

According to the injection treatment method of the present invention, a cup-shaped dipping free board, which is passed through a lance, is partially dipped into molten steel or hot metal in a container and is covered with a treatment agent from the lance. In the injection treatment method of refining by blowing into molten steel or hot metal together with gas, the gap between the immersion freeboard and the container is covered with a sloping prevention plate, and the immersion freeboard used in this method is A feature is that a sloping prevention plate that covers a gap between the board and the board is attached.

According to this method and the immersion freeboard, slag, molten steel or hot metal which is about to be scattered from between the container and the immersion freeboard during the injection treatment is stopped by the sloping prevention plate and does not scatter out of the container. If the sloping prevention plate is brought into contact with the container, slag, molten steel, or hot metal does not spout from between the container and the bottom surface of the sloping prevention plate is provided with an irregular refractory material. There is no difficulty in removing the anti-lopping plate and the container.

In the present invention, the anti-slopping plate is
The immersion free board may be formed separately from the immersion free board so as to be inserted into the immersion free board, but it is preferable that the immersion free board is integrally formed with the immersion free board. As a result, it is possible to save the work of mounting the sloping prevention plate on the immersion freeboard, and to prevent slag, molten steel, or hot metal from leaking from the space between the immersion freeboard and solidifying by entering between them. Is not unstablely fixed to the immersion freeboard, and the container and the immersion freeboard can be positioned by applying the container to the anti-slopping plate.

In order to integrally form the sloping prevention plate with the immersion freeboard, an iron skin for reinforcing the sloping prevention plate is provided to have strength, and is integrated with the iron skin for reinforcing the immersion freeboard by fixing or the like. It is desirable to configure
In this case, the surface against which the slag, the molten steel or the hot metal hits should be made of a refractory so that the iron shell does not melt.

[0010]

[Example] In order to dephosphorize the hot metal 3 in the hot metal ladle 5, as shown in FIG. When the sloping prevention plate 6 integrated with the above is in contact with the pan 3, a dephosphorizing agent containing lime and sinter as the main components is blown into the molten pig iron 3 from the lance 2 using N ₂ as a carrier gas. Immersion freeboard 1 when treated with a conventional immersion freeboard without the anti-slopping plate as shown in FIG.
There was a maximum of about 20 times of sloping in 1 minute from between the hot metal ladle 5 and the hot metal ladle 5, whereas there was no dipping free board with a sloping prevention plate.

FIG. 3 shows an example of a dipping free board with a sloping preventive plate, in which a brim 8 is formed to project laterally around the lower portion of a cup-shaped iron shell 7 having an inverted U-shaped cross section. The inner surface, the lower surface of the collar, and the outer surface of the iron shell below the collar are provided with a layer 9 made of an irregular refractory material. FIG. 4 shows an example in which the sloping prevention plate 6 is configured separately from the immersion free board 1, and an existing immersion free structure in which a layer 9 having an irregular refractory material sprayed on the inner and outer surfaces of the iron shell 11 is provided. Board 1 with ring-shaped iron skin 13
2 shows an example in which a sloping prevention plate 6 having an irregular refractory layer 9 provided on the surface thereof is inserted.

[0012]

The present invention is constructed as described above and has the following effects. According to the injection treatment method of claim 1 and the immersion freeboard of claim 2 used in the method, sloping between the container and the immersion freeboard can be eliminated during the injection treatment of molten steel or hot metal. As a result, operating problems such as equipment troubles such as inability to run a trolley caused by this sloping, increase in the frequency of trolley cleaning, decrease in yield, etc. will be solved, resulting in improvement in productivity and cost. It becomes possible to reduce the amount.

If the sloping prevention plate is provided separately as in the immersion freeboard according to the third aspect, it is possible to attach the sloping prevention plate to an existing immersion freeboard, and between the containers. It becomes possible to prevent the slopping. According to the immersion freeboard of claim 4, as compared with the case where the sloping prevention plate is provided separately, the work for attaching the sloping prevention plate is unnecessary, and the slag, molten steel or hot metal leaks from between the immersion freeboard. It is also possible to prevent the sloping prevention plate from being fixed in an unstable state by taking it out or getting in between and solidifying, and it is also possible to position the container and the immersion freeboard.

According to the slopping prevention plate of the fifth aspect, since it is reinforced by the iron shell and the irregular shaped refractory layer is provided on the lower surface, it does not melt or adhere to the container.

[Brief description of drawings]

FIG. 1 is a schematic sectional view according to a conventional method.

FIG. 2 is a schematic sectional view according to the method of the present invention.

FIG. 3 is a sectional view of the immersion freeboard according to the present invention.

FIG. 4 is a sectional view of another embodiment of the immersion freeboard.

[Explanation of symbols]

1 ... Immersion free board 2 ... Blowing lance 3 ... Hot metal or molten steel 4 ... Slag 5 ... Container (pot) 6 ... Sloping prevention plate 7 ... Cup-shaped iron skin 8 ... Tsuba 9 ... Unshaped refractory layer 11 ... Iron skin 13 ... Annular iron skin

Claims (5)

[Claims] 1. In a state where a cup-shaped dipping freeboard having a lance passed through the molten steel or hot metal in the container is partially dipped and covered, a treating agent is blown into the molten steel or hot metal together with a carrier gas from the lance for refining. In the injection treatment method, the gap between the immersion freeboard and the container is covered with a sloping prevention plate, which is an injection treatment method. 2. The immersion freeboard used in the method according to claim 1, further comprising a sloping prevention plate which covers a gap between the container and the immersion freeboard. 3. The immersion freeboard according to claim 1, wherein the sloping prevention plate is a separate member, has an annular shape conforming to the shape of the upper surface of the container, and is detachably fitted into the immersion freeboard. 4. The immersion freeboard according to claim 1, wherein the sloping prevention plate is integrally formed. 5. The immersion freeboard according to claim 3, wherein an upper surface of the anti-slopping plate is integrated with the metal object of the immersion freeboard, and an irregular refractory material is provided on the lower surface.