JPH06257948A - Gas blowing type bottom blow tuyere for fused metal container replacing of the same - Google Patents

Abstract

PURPOSE:To lengthen a substantial duration of a gas blow nozzle to blow in gas from a bottom part of a fused metal container of an upper bottom blow type converter, an electric furnace or the like, and a bottom tuyere having this kind of gas blow nozzle. CONSTITUTION:A bottom blow tuyere comprising a hearth fire-proof brick 3 arranged under a container bottom surface 2a of a container bottom part 2 of a fused metal container a single gas blow nozzle 8a mounted to stir by force fused metal in the container and a tuyere brick 8b, is divided preparatorily into two steps, an upper step defining a wear margin of the tuyere and the hearth fire-proof brick 3 around the tuyere and a lower step defining an unwearable range. The upper step is a bottom blow tuyere 17 which comprises a single gas blow nozzle 17a which is the same as the gas blow nozzle 8a or has an external dimension substantially the same as that of the gas blow nozzle 8a, and a large-sized tuyere brick 17b for replacement which is to be mounted by insertion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom blowing tuyere (hereinafter, simply referred to as a bottom blowing tuyere for blowing gas from the bottom (furnace bottom) of a molten metal container (furnace) such as an upper bottom blowing converter or an electric furnace. (It may be called a tuyere) structure and a method for exchanging this bottom-blown tuyere.

[0002]

2. Description of the Related Art In recent years, in a molten metal container (furnace) such as an upper-bottom blowing converter or an electric furnace in a steelmaking process, a bottom-blowing tuyere having a nozzle for blowing a refining gas is arranged at the bottom of the furnace. , By injecting oxygen, nitrogen, carbon monoxide, carbon dioxide, hydrocarbons, inert gas, etc. or a suitable blend gas of these gases from this gas injection nozzle, the molten metal is forcibly stirred and melted. It promotes melting and dissolution of various raw materials charged in a metal container, or promotes reaction to enhance refining effect. However, when the refining gas is blown in this way, as the melting or melting or refining progresses, especially the tuyere with the gas blowing nozzle and the hearth refractory bricks in the vicinity thereof are filled with molten metal (for example, hot metal or molten steel). ) Or slag is violently agitated by forced agitation, and the life of the tuyere limits the life of the entire molten metal container.

In order to prolong the life of the molten metal container, the structure of the tuyere with the gas blowing nozzle is improved, and at the stage of such refining, the operation of the molten metal container is stopped and the tuyere and its surroundings are stopped. How to replace the hearth refractory brick in
For example, as proposed in Japanese Utility Model Publication No. 1-89947,
Then, JP-A-4-173915 and JP-A-4-1-1
It is proposed as in Japanese Patent Publication No. 87728.

4 and 5 show an embodiment of an electric furnace, and are a plan sectional view and a side sectional view in which a part of the furnace is omitted. As shown in both figures, a hearth refractory brick 3 which is a wear-resistant refractory brick and which is used (operated) entirely or locally by relining is provided in the furnace bottom portion 2 of the electric furnace 1 as a molten metal container. The furnace is arranged concentrically and has a slender, truncated cone-shaped gas blowing nozzle 8a in the middle, and a truncated pyramid-shaped tuyere brick 8b with the gas blowing nozzle 8a inserted. It is equipped with three bottom-blown tuyere 8 and is similarly equipped with a blind nozzle 9a and this blind nozzle 9a.
A large number of spare bottom-blown blind tuyere 9 composed of tuyere bricks 9b and the like to which are attached are attached.

In FIG. 6, three layers of hearth permanent refractory bricks 4 are attached inside the furnace of a steel shell 7 to form bricks 5 and 6 with holes, and three layers of hearth permanent refractory bricks 4 are attached. Bottom 2 of electric furnace 1 in which hearth refractory bricks 3 are arranged and built
Is shown, and the state in which a new tuyere 8 is attached to and attached to a new hearth refractory brick 3 or the like of the hearth bottom 2 is shown in detail. The gas injection nozzle 8a inserted into the tuyere brick 8b of the tuyere 8 is attached to the flange 12 fixed to the other end of the tubular body 11 fixed to the iron skin 7,
A fixing bolt 14 and a fixing nut 15 each having a length of up to 100 mm fix the flange 13 which is divided into two parts in the central portion so as to be easily opened so that they can be tightened and loosened. 16 is a retaining nut. Not limited to this gas blowing nozzle 8a,
The above-mentioned blind nozzle 9a has the same shape and structure except that it is in a blind state, and thus is fixed in the same manner.

The gas injection nozzle 8a and the blind nozzle 9a are
A threaded portion 8ab and a threaded portion 9ab (not shown) are engraved on the outer peripheral surface of a gas introduction pipe 8aa and a detachable pipe 9aa (not shown) protruding at the lower end portions thereof, respectively, and a fixing bolt 14 and a fixing nut 15 are provided. Inserted in both flanges 12 and 13 that are fixed by overlapping with each other, and tightened and tightened with fasteners 8ac and 9ac (not shown) such as nuts from both sides of the flanges 12 and 13 so that the gas introduction pipe 8aa and the detachable pipe 9aa are vertically moved. By forcibly moving it in the direction, it can be used by inserting it into the hearth refractory brick 3 of the hearth bottom part 2 and mounting it or pulling it out.

Therefore, a predetermined gas is blown from the bottom blowing tuyere 8 composed of the gas blowing nozzle 8a and the tuyere brick 8b mounted on the furnace bottom portion 2 of the electric furnace 1, as shown in FIG. As described above, when the tuyere 8 is worn and reaches the end of its life, the gas blowing from the gas blowing nozzle 8a is stopped, and the gas is not blown near the gas blowing nozzle 8a, so that it is not worn so much. One of the bottom blown blind tuyere 9 to blind nozzle 9a
And replace it with a new gas blowing nozzle 8a, and replace the entire tuyere 8 that has reached the original life with a spare bottom blowing blind tuyere 9 that has a blind nozzle 9a. The gas is continuously blown from the injection nozzle 8a. However, as shown in FIG. 7, even when the tuyere 8 and its surrounding hearth refractory bricks 3 gradually wear out and reach the end of their lives (on the way), the gas injection from the gas injection nozzle 8a is stopped. Remove the gas injection nozzle 8a from the tuyere brick 8b of the tuyere 8, insert a new elongated gas injection nozzle 8a as shown in FIG. 8 and install it, and then wear the hearth refractory brick 3 Stamp the part with an amorphous refractory (castable) 10 such as magnesia (MgO) or magcro (MgO.Cr ₂ O ₃ ), and reshape the bottom 2 of the furnace, that is, replace it with a new gas injection nozzle 8a. Then, not only the gas injection nozzle 8a but also the surrounding hearth refractory bricks 3 are extended as long as possible, and gas injection is continued to repeatedly perform bottom injection operation.

[0008]

However, as shown in FIG. 8, when the tuyere 8 and the surrounding furnace hearth refractory bricks 3 around the tuyere 8 are worn as shown in FIG. Even if the nozzle 8a is replaced and the surrounding area is stamped with an amorphous refractory (castable) 10 and the furnace bottom 2 is reshaped and gas is blown, the amorphous refractory stamped in such a state (Castable) 10 is a hearth refractory brick 3 originally arranged in concentric circles as shown in FIGS.
Compared with, the forced agitation of molten steel, hot metal, or slag caused by gas injection causes more violent and easier movement or wear, and as shown in FIG. As a result, the forced agitation or the like causes thermal or mechanical spalling and is very likely to be damaged or worn. Therefore, even if it is attempted to extend the service life of the tuyere 8 by replacing the furnace bottom 2 with a new gas injection nozzle 8a and extending the service life of the tuyere 8, its effect is diminished, and the life of the gas injection nozzle 8a is greatly reduced. However, it is difficult to blow gas for a long time, which should be possible originally, and not only the service life is shortened in this way, but also the service life of the surrounding hearth refractory bricks 3 is shortened, so that the service life of the entire furnace bottom 2 is shortened. As a result, the gas blowing nozzle 8a, the tuyere 8 having the gas blowing nozzle 8a, and the furnace bottom portion 2 including the hearth refractory bricks 3 are often inefficiently stopped, but Although it is uneconomical, there is a problem that it has to be replaced or replaced frequently. For this reason, there is a problem in that workability and safety are likely to occur, and it is not possible to improve the process productivity and productivity of a process having a molten metal container (furnace) such as the electric furnace 1.

Therefore, the present invention solves the problems detailed above, and extends the substantial useful life of the gas blowing nozzle and the bottom blown tuyere having the gas blowing nozzle, whereby the hearth fireproof To provide a simple and effective bottom-blowed tuyere structure and a simple method for replacing the tuyere to extend the service life (number of furnace operations) of the furnace bottom made of bricks and the entire molten metal container. This is an issue.

[0010]

In view of the problems detailed above, the inventors of the present invention have conducted various experiments and surveys to achieve the above-mentioned problems, and as a result, (a) are mounted at a predetermined position on the bottom of the furnace. The bottom-blowing tuyere with the gas blowing nozzle, which is being replaced, is cyclically reattached to the position where the bottom-blowing blind tuyere with the next blind nozzle is attached, and then the gas blowing is not performed. In the continuously operating molten metal container, the bottom-blown tuyere that actually injects gas and the hearth refractory bricks around it are better than the bottom-blown tuyere and the surrounding hearth refractory bricks. Since it is severely and greatly damaged and worn, the wear of the bottom blown tuyere and its service life limit the service life of the bottom of the furnace and the entire molten metal container (furnace). Service life of the entire metal container (number of furnace operations In order to extend the length of the bottom blown tuyere, it is necessary to extend the useful life of the hearth refractory bricks around it as much as possible. Therefore, the thin tuyere brick into which the gas blowing nozzle is inserted is relatively easily worn together with the gas blowing nozzle, and the life of the essential gas blowing nozzle cannot be extended. As a problem to be solved by the above, when the bottom blown tuyere is worn out and replaced as described above, the newly installed gas blowing nozzle is in a protruding state, and the periphery of this nozzle is stamped with an irregular refractory. With the conventional replacement method such as reshaping the furnace bottom, the protruding part of this nozzle is easily damaged and the life of the essential gas injection nozzle cannot be extended. It must not improve these, it was to investigate the like.

In order to achieve the above object in such a molten metal container, therefore, the wear range of the bottom blown tuyere installed under the bottom surface of the bottom of the vessel and the hearth refractory bricks arranged around it The upper part is the part that is also the allowable wear range, and the lower part is the part that is not worn. On the other hand, the upper part is the same as the conventional one. A bottom-blown tuyere structure consisting of a single gas-blowing nozzle, which is the same as or substantially the same as the nozzle in external dimensions, and a large replacement tuyere brick, into which such a nozzle is inserted and attached; and When exchanging such a bottom blowing tuyere, it is necessary to use and install a new one genuine gas blowing nozzle as described above every time the replacement is performed. Tuyere Of the large tuyere brick to be replaced, or more specifically, the entire upper tier constructed in this way is replaced or the effective length of the large tuyere brick for replacement remains in this upper tier. It is recognized that the large tuyere brick is continuously used as it is, only the gas injection nozzle is replaced, and the boundary between the replacement large tuyere brick in the upper part and the surrounding hearth refractory brick As a result of completing the present invention, we have obtained the knowledge that it is sufficient to fill an irregular shaped refractory into the narrow space provided in the section and also in the worn part of the worn-out hearth refractory brick to form the bottom surface of the vessel. is there.

The structure of the gas blowing bottom blowing tuyere for a molten metal container and the method for replacing the tuyere according to the present invention will be described below.
As described in the related art, a detailed description will be given with reference to the drawings based on an embodiment in an electric furnace as a molten metal container. FIG. 1 is a front cross-section of a new bottom blown tuyere attached to and mounted on a new hearth refractory brick or the like that is arranged and constructed in the furnace bottom of an electric furnace as a molten metal container in one embodiment of the present invention. FIG. 2 is a front cross-sectional view showing the worn state of the bottom blown tuyere and the hearth refractory bricks around it as shown in FIG. 1,
FIG. 3 is a front cross-sectional view showing a state in which the bottom blown tuyere in the worn state shown in FIG. 2 and the hearth refractory bricks around it are replaced and repaired and continued to be used (operating) again. Further, in FIG. 4, as in the prior art, a bottom-blowing tuyere and a bottom-blowing blind tuyere are mounted at predetermined positions on the bottom of the electric furnace in which a part of the furnace as a molten metal container is omitted in the embodiment of the present invention. FIG. 5 is a side sectional view showing the state, and FIG. 5 is a side sectional view of FIG. In order to explain the present invention below with reference to FIGS. 1 to 5, it is necessary to make the same changes as those used in the description of the above-mentioned [Prior Art] and [Problems to be Solved by the Invention] Those that do not have the same reference numbers will be described.

In an electric furnace 1 as a molten metal container to which a gas blowing bottom blowing tuyere for a molten metal container according to the present invention is attached, as shown in a plan sectional view of FIG. 4 and a side sectional view of FIG. Bottom blowing tuyere 17 having gas blowing nozzles 8a and 17a is attached to each predetermined position of the furnace bottom 2. On the other hand, the bottom-blown blind tuyere 9 having the tuyere brick 9b into which the blind nozzle 9a is inserted is also mounted at each predetermined position as in the conventional case. Bottom blowing tuyere
When the time has come to replace the new (new) one after the 17 has been worn out, the bottom blown tuyere 17 has the position where the bottom blown blind tuyere 9 having the next blind nozzle 9a is mounted as in the conventional case. After being re-installed cyclically, the gas is continuously blown in and the operation is continued.

The structure of the gas blowing bottom blowing tuyere 17 for a molten metal container according to the present invention used in such an electric furnace 1 will first be described with reference to FIGS. As shown in FIG. 1, hearth refractory bricks 3 are arranged below the bottom surface 2a of the bottom 2 of the furnace.
The gas blown bottom blowing tuyere 17 for a molten metal container according to the present invention, which is installed in the above, is the wear range of the bottom blowing tuyere 8 and the surrounding hearth refractory brick 3 which have been conventionally used as described above. Moreover, a portion which is also a wear allowable range described later is defined as an upper step portion, and a portion which is not worn is a lower step portion which is preliminarily divided into a two-step structure, and the upper step portion is a single piece which has been conventionally used. A single gas blowing nozzle 17a which is the same as the gas blowing nozzle 8a or which has at least substantially the same outer dimensions as the inside of the gas blowing nozzle itself is changed, and such a nozzle 8a, 17a is inserted. It is configured as a bottom blown tuyere consisting of a large tuyere brick 17b for replacement to be attached.

Such a bottom blown tuyere 17 is formed by filling the boundary between the large replacement tuyere brick 17b and the surrounding hearth refractory brick 3 with the irregular refractory material 10 in the upper part thereof. It is preferable to have the narrow space 17c. In addition, the upper part of the bottom blowing tuyeres 17 is economical in terms of overall cost reduction, and the tuyeres 17 and the surrounding hearth refractory bricks 3 that are the most severely worn at the bottom 2 of the furnace. In order to secure the safety against the leakage of molten metal (leakage of molten metal), and to prevent the replacement of the entire tuyere 17 and nozzles 8a and 17a alone, Furnace stop reference line Z empirically determined from the bottom 2a of the bottom 2 of the furnace
Up to [X (mm)] and not less than 1/2 and not more than 2/3 of the thickness [Y (mm)] of the layer of the hearth refractory bricks 3 arranged under the bottom surface 2a of the furnace. It is preferable to set a wear allowance range having a length.

On the other hand, in the lower part which is not worn, the same description as the conventional one will be used, and thus the duplicated description will be omitted. However, the tuyere brick 8b in which the gas blowing nozzles 8a and 17a are inserted and attached is attached. The fixed bricks 8 are fixed without replacement while partitioning the hearth refractory bricks 3 around them.
It can be b '.

Next, a method of replacing the gas blowing bottom blowing tuyere 17 for a molten metal container according to the present invention having the above-described structure will be described with reference to FIGS. The new (new) bottom blown tuyere 17 as shown in FIG. 1 is replaced each time in a process in which the blown tuyere 17 gradually wears while continuously blowing gas as shown in FIG. 2 in the repeated operation. When the bottom blowing tuyeres 17 and their surrounding hearth refractory bricks 3 are exhausted for their useful lives, the bottom blowing tuyeres 17 are exhausted for their useful lives. When replacing the entire mouth 17 (actually, the entire next bottom-blown blind tuyere 9) [B] and the effective length of the replacement large tuyere brick 17b that is actually used for the next bottom-blown blind tuyere 9 However, there is a case [C] in which only the gas blowing nozzles 8a and 17a are replaced when the remaining large tuyere brick is continuously used as it is.

[A] in the method for replacing the gas blowing bottom blowing tuyere 17 for a molten metal container according to the present invention
In either of the cases of [B] and [C], only the gas blowing nozzles 8a and 17a are replaced with new ones at the time of the replacement, but basically the bottom having the above-mentioned structure is used. Only the upper end of the tuyere 17 is replaced. In the case of the above [A], after the replacement, only the upper stage portion is mounted on the surrounding hearth refractory brick 3 as shown in FIG. In the case of the above [B], the bottom blown tuyere 17 mounted as shown in FIG. 1 has worn out the length [X (mm)] to the furnace stop reference line Z as shown in FIG. After that, as shown in FIG. 3, the gas injection nozzle 8 in the upper stage is
Replacement large tuyere bricks with a and 17a inserted and installed
17b is installed, and the narrow space 17c provided at the boundary between the large tuyere brick 17b and the surrounding hearth refractory bricks 3 and the worn hearth refractory bricks 3 has a non-shaped refractory ( Castable) 10 is filled and the bottom surface 2a of the furnace bottom portion 2 is exchanged so as to be molded. In the case of [C] above,
The remaining large tuyere brick 17b shorter than the length [X (mm)] to the furnace stop reference line Z is replaced in the same manner as in the case [B] described above with reference to FIG.

[0019]

The gas blowing bottom blowing tuyere 17 for a molten metal container according to the present invention has a very simple structure as described above with reference to FIGS. 1 to 3 and 4, and only the upper stage portion thereof is provided. It is a simple method of exchanging exclusively. As shown in FIGS. 1 and 3, in any of the exchanging methods [A] to [C], the surface on which the large tuyere brick 17b to be replaced is placed is always provided as an accurate flat surface. With this large tuyere brick
Since a narrow space 17c formed by filling the irregular refractory material 10 at the boundary between the 17b and the surrounding hearth refractory bricks 3 is provided later, the replacement work is very accurate and the workability is good. Can be done efficiently. The bottom blown tuyere 17 thus constructed and mounted has the thin tuyere brick 8b as described above with reference to FIGS. 6 and 8 and is worn out relatively easily in the conventional bottom blown tuyere 8b. It seems that the amorphous refractory stamped after the replacement or its replacement is easily moved and flown, and the newly replaced and installed gas injection nozzle 8a easily protrudes and is easily damaged. Unlike other conventional replacement methods, large tuyere bricks for constant replacement 17
Since b exists and the gas blowing nozzles 8a and 17a are sufficiently protected and the resistance to damage and wear and the durability are greatly increased, the service life of the bottom blowing tuyere 17 is greatly extended. You will get it. Therefore, it becomes possible to extend the useful life of the hearth refractory bricks 3 around the tufted tuyere 17 as well as the life of the furnace bottom 2 and the entire furnace 1. It can be extended.

[0020]

【Example】

Comparative Example (Conventional Method) As shown in FIGS. 4 and 5, a bottom-blowing tuyere 8 and a bottom-blown blind tuyere 9 were attached to the bottom 2a of the bottom 2 of the furnace, respectively.
As a result of continuous experimental operation while cyclically exchanging the bottom blown tuyere 8 having the structure shown in FIGS. 6 to 8, as a result, the furnace operation frequency (times) and the hearth refractory brick 3 shown in FIG. The relationship with the remaining amount (remaining size) (mm) was obtained. The thickness [Y (mm)] of the new hearth refractory brick 3 shown in FIG. 6 is 550 mm as shown in FIG. In addition, the bottom blown tuyere 8 and the surrounding hearth refractory bricks 3
Empirically set the residual size (mm) of the hearth refractory brick 3 to 150 mm as the furnace stop reference line [Z (mm)] for ensuring safety against molten metal (leakage of molten metal) from did. Under these conditions, the bottom-blown blind tuyere 9 and the surrounding hearth refractory bricks 3 are worn away as shown by the alternate long and short dash line, so that new (new) gas injection as shown in FIG. The bottom blown tuyere 8 composed of the nozzle 8a and the tuyere brick 8b and the hearth refractory bricks 3 around the bottom blown tuyere 8 are worn as shown by the solid line with arrows. That is, the bottom blown tuyere 8 was replaced 320 times by inserting only the new gas blowing nozzle 8a into the tuyere brick 9b of the next worn down bottom blown tuyere 9 after the furnace was operated 320 times. The bottom-blown blind tuyere 9 which was used continuously afterwards and was worn out further after 640 furnace operations.
Insert the new gas blowing nozzle 8a only into the tuyere brick 9a and replace it (second time), then continue to use it, and finally, with the furnace operating frequency of 960 times, the bottom blowing tuyere 8 and its whole The remaining size of the surrounding hearth refractory bricks 3 is the furnace stop reference line [Z ...
150 mm], the operation could not be resumed unless all the bottom of the bottom 2a of the bottom 2 of the furnace was replaced and replaced as shown in FIG.

Example (Invention Method) As shown in FIGS. 4 and 5, a gas-injected bottom-blown tuyere 17 and a bottom-blown blind tuyere according to the invention (other than actually having a blind nozzle 9a). Are of the same structure as the bottom blown tuyere 17) and below the bottom surface 2a of the bottom 2 of the furnace, and the upper part of the bottom blown tuyere 17 of the structure shown in FIGS. As a result of experimental operation while exchanging with clicks, the relationship between the number of furnace operations (times) and the remaining amount (remaining size) (mm) of the hearth refractory brick 3 was obtained as shown in FIG. The settings of the thickness [Y (mm)] of the hearth refractory bricks 3 and the furnace stop reference line [Z (mm)] are exactly the same as in the case of the comparative example. As a result of operating under such conditions, the bottom blown tuyere 17 and the hearth refractory bricks 3 around the bottom blown tuyere 17 are worn out as shown by the one-dot chain line, and compared with the conventional comparative example shown in FIG. The wear gradient was small and it was difficult to wear. Therefore, as shown in FIG. 1, a bottom (blown) tuyere 17 composed of new (new) gas blowing nozzles 8a, 17a, a large tuyere brick 17b for replacement, and the hearth refractory brick 3 around it are indicated by arrows. They were worn out as shown by the solid line. That is, bottom blown tuyere 17
Was replaced with a new bottom-blown tuyere 17 including the large tuyere brick 3 for replacement with 320 times of furnace operation (first time), so it can be used continuously from almost the same state as the starting stage (550 mm). After the furnace was operated 640 times, only the new gas blowing nozzles 8a and 17a were inserted into the large tuyere brick 17b for replacement of the next worn bottom-blind blind tuyere to replace it.
After that, the new gas injection nozzles 8a, 17a are inserted only into the large tuyere brick 17b for replacement of the bottom blown tuyere that has been worn out after the furnace has been operated 960 times. After exchanging (2nd), continue to use,
Finally, after the number of furnace operations was 1150, the remaining size (mm) of the bottom-bottomed tuyere 17 and the surrounding furnace bottom refractory bricks 3 reached the furnace stop reference line [Z ... 150 mm], and the furnace bottom 2 Bottom 2a
The operation could not be resumed unless all the lower parts were replaced and replaced as shown in FIG.

By carrying out the method for replacing the gas blowing bottom blowing tuyere 17 for a molten metal container according to the present invention, the service life of the hearth refractory brick 3 is extended 190 times as compared with the comparative example. As a result, each bottom blown tuyere 17 can be replaced smoothly with good workability. Then, the service life of the bottom blown tuyere 17 is extended and adjusted from the viewpoint of the material so that the repair cycle of the electric furnace 1 that is carried out at a predetermined cycle of, for example, 2 weeks or 1 month can be met. If you also extend and adjust the service life of the hearth refractory bricks 3 to balance the service life of the bottom blower tuyere 17 and its replacement time by several times, keep the furnace cool enough. The bottom blown tuyere 17 having the large tuyere bricks 17b for replacement can be replaced, and when the bottom blown tuyere 17 is replaced, the worn-out large tuyere bricks of the bottom blown blind tuyere 9 are replaced.
Increase the frequency with which gas can be blown while protecting the tips of the new gas injection nozzles 8a and 17a that have been installed by inserting the 17b into a new large tuyere brick 17b without diversion. As a result, it becomes possible to extend the service life of the furnace bottom portion 2 and thus the entire furnace 1 more economically.

[0023]

The structure of the gas blowing bottom blowing tuyere for the molten metal container (furnace) and the method for replacing the tuyere according to the present invention, which have been described in detail above, have a simple bottom blowing tuyere structure. Although it is a simple replacement method, it has the excellent effects as listed below, and since it is possible to perform stable gas injection to the molten metal in the container without trouble, it is charged in the container. The promotion of melting and melting of the raw materials is very effective industrially because the refining effect of the molten metal is sufficiently enhanced. 1) Unlike the conventional bottom blown tuyere structure and its replacement method, a new, single gas injection nozzle that is renewed every time the bottom blown tuyere is replaced is as large as possible up to the tip, with fire and wear resistance. Since it can be sufficiently protected by using a replacement tuyere brick, it will be possible to effectively use the original life of the gas blowing nozzle without waste, and to identify this bottom blowing tuyere. From the structure, it becomes possible to extend the service life of the hearth refractory bricks around it as well. Therefore, it is possible to extend the service life of the vessel bottom (furnace bottom) and the entire container (furnace). 2) In other words, in the bottom of the conventional unit (furnace bottom), the bottom blown tuyere and the furnace bottom refractory bricks around it that are severely and heavily worn ahead of other parts are not limited to this bottom (furnace bottom). It was possible to prevent as much as possible from limiting the life of the entire container (furnace), and to greatly improve it. 3) Although it is inefficient in the past, it is often impossible to stop the furnace operation,
Although it is uneconomical, it has become possible to suppress the need to frequently replace the bottom blowing tuyere and replace the hearth refractory brick. As a result, it becomes possible to avoid defective workability and unsafety that accompany these operations as much as possible. 4) Therefore, the production capacity of the container (furnace) and the productivity of the steelmaking process having this container (furnace) can be greatly improved.

[Brief description of drawings]

FIG. 1 is a front view of a new bottom blown tuyere attached to and mounted on a new hearth refractory brick or the like which is arranged and constructed in the furnace bottom of an electric furnace as a molten metal container in one embodiment of the present invention. FIG.

FIG. 2 is a cross-sectional view showing a worn state of the bottom blown tuyere shown in FIG. 1 and a hearth refractory brick around it.

FIG. 3 is a front cross-sectional view showing a state in which the bottom blown tuyere in the worn state shown in FIG. 2 and the hearth refractory bricks around it are replaced and repaired and continued to be used (operating) again.

FIG. 4 shows a conventional and one embodiment of the present invention in which a bottom blowing tuyere and a bottom blowing blind tuyere are mounted at predetermined positions on the bottom of an electric furnace in which a part of the furnace as a molten metal container is omitted. It is a plane sectional view shown.

5 is a side sectional view of FIG.

FIG. 6 is a front sectional view of a new bottom blowing tuyere attached to a new hearth refractory brick or the like built in the bottom of an electric furnace as a molten metal container in a conventional example.

7 is a front cross-sectional view showing the conventional bottom blown tuyere shown in FIG. 6 and the wear state of the hearth refractory bricks around it.

8 is a front cross-sectional view showing a state in which the conventional bottom blown tuyere in the worn state shown in FIG. 7 and the hearth refractory bricks around it are replaced and repaired and continued to be used (operating) again. .

FIG. 9 is a relational diagram between the number of furnace operations and the remaining amount (remaining size) of hearth refractory bricks in the conventional method of continuously operating while replacing the conventional bottom blowing tuyere.

FIG. 10 is a relationship diagram between the number of furnace operations and the remaining amount (remaining size) of hearth refractory bricks in the method of the present invention in which the bottom blowing tuyere of the present invention is continuously used (operating) and restarted while being replaced. .

[Explanation of symbols]

1 Molten metal container (electric furnace, etc.) 2 Bottom (furnace bottom) 2a Bottom (furnace bottom) 3 Hearth refractory brick 4 Hearth permanent refractory brick 5 Fixed brick 6 Fixed brick 7 Iron skin 8 Conventional bottom blowing tuyere 8a Gas injection nozzle 8aa Gas inlet pipe 8ab Screw part 8ac Fixed nut 8b Tuyere brick 8b ′ Fixed brick 9 Conventional bottom blow blind tuyere 9a Blind nozzle 9aa Removable pipe 9ab Threaded part 9ac Fixed nut 9b Tuyere brick 10 No Fixed refractory (castable) 11 Cylindrical body 12 Flange 13 Two-piece flange 14 Fixing bolt 15 Fixing nut 16 Locking nut 17 Bottom blowing tuyere 17a Gas blowing nozzle 17b Large tuyere brick 17c Narrow space X according to the present invention Length from bottom surface 2a of furnace (furnace) to furnace stop reference line Z (mm) Y Thickness of layer of hearth refractory brick 3 at bottom 2 of furnace (furnace) (length)
(Mm) Z furnace stop reference line (usage limit level)

Claims (6)

[Claims] 1. A vessel bottom (2) in a molten metal container (1)
A single gas injection nozzle (for attaching the molten metal in the molten metal container (1) to the hearth refractory bricks (3) arranged under the vessel bottom surface (2a) forcibly stirring the molten metal ( 8a) and tuyere brick
The bottom blown tuyere (8) composed of (8b) is the bottom blown tuyere.
(8) and the surrounding hearth refractory bricks (3) are preliminarily divided into a two-stage structure including an upper step part which is a wear allowable range and a lower step part which is not worn, and the upper step part is the gas blowing Same as nozzle (8a) or substantially the same in external dimensions 1
It is a bottom blowing tuyere (17) consisting of a genuine gas blowing nozzle (17a) and a large replacement tuyere brick (17b) to which the gas blowing nozzles (8a, 17a) are inserted and attached. The structure of the gas blowing bottom blowing tuyere for the characteristic molten metal container. 2. A tuyere brick (8b) in which a gas blowing nozzle (8a, 17a) is inserted and attached at a lower stage portion of a bottom-blown tuyere (17).
2. The structure of a gas-bottomed tuyere for a molten metal container according to claim 1, wherein is a shaped brick (8b ') fixed without replacement while partitioning the surrounding hearth refractory bricks (3). 3. An irregularly shaped refractory (10) having a bottom blown tuyere (17) at the boundary between a large-sized replacement tuyere brick (17b) in the upper part and the surrounding hearth refractory brick (3). Narrow space filled with (17c)
The structure of the gas-bottomed tuyere for a molten metal container according to claim 1 or 2, further comprising: 4. The bottom part of the bottom tuyeres (17) is the bottom part (2).
From the bottom surface (2a) of the furnace to the furnace stop reference line (Z) [X (m
m)] and the thickness [Y (mm)] of the hearth refractory brick (3) layer arranged under the bottom surface (2a) is 1/2 or more and 2/3 or less. The structure of the gas-bottomed tuyere for a molten metal container according to any one of claims 1 to 3. 5. A two-tiered structure comprising an upper stage part which is a wear allowable range of a bottom blown tuyere (8) and a hearth refractory brick (3) around it and a lower stage part which is not worn is preliminarily divided. ,
A single gas injection nozzle (17) whose upper portion is the same as the gas injection nozzle (8a) or has substantially the same external dimensions.
Bottom blown tuyere consisting of a) and a large replacement tuyere brick (17b) to which this gas blowing nozzle (8a, 17a) is inserted and attached
When replacing (17), a method for replacing a gas blown bottom blowing tuyere for a molten metal container is characterized in that only the upper stage portion is replaced. 6. A method for exchanging only the upper stage portion of the bottom blown tuyere (17), wherein all the upper stage portions of the bottom blown tuyere (17) are replaced, or a large wing for exchange in the upper stage portion. Mouth brick (17b)
When continuing to use the gas injection nozzle (8a, 1
Only the 7b) is replaced, and the narrow space (17c) and the worn-out hearth at the boundary between the replacement large tuyere brick (17b) and the surrounding hearth refractory brick (3) in the upper part Refractory brick
Fill the wear part of (3) with irregular shaped refractory material (10) and fill the bottom surface (2a)
The method for exchanging a gas blown bottom blown tuyere for a molten metal container according to claim 5, which comprises molding.