JP2019014952A - Treatment method of molten iron tapped from blast furnace - Google Patents

Abstract

To provide a method for treating molten iron tapped from a blast furnace, which can further shorten the repairing period while further reducing the repairing cost of the blast furnace.SOLUTION: In the treatment method of molten iron tapped from a blast furnace, molten iron tapped from a tap hole of the blast furnace 1 is discharged via a tapping flume to a recess 4 which is fixed to the ground, and the molten iron is solidified in the recess 4. A cover 5 for covering the whole surface of the discharged molten metal is provided to the recess 4, and the molten metal is discharged to the recess 4 provided with the cover 5.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for treating hot metal discharged from a blast furnace, and, for example, relates to a method for treating hot metal discharged from the blast furnace at the time of blowout at the time of blast furnace repair.

In blast furnaces, lining refractories and furnace body cooling facilities deteriorate and break down with long-term operation, so refurbishment is regularly performed to repair and replace them.
There are various ways to repair the blast furnace. For example, one of the blast furnaces operating in a two-unit system is blown off, and the iron skin is used as it is. So-called “iron-layer refurbishment”, which repairs or replaces, is attracting attention.

Such a refurbishment of the iron skin does not require a new construction of the iron skin, so the cost can be greatly reduced. Nonetheless, during the refurbishment, the system will be operated in a single system, so a renovation period in the shortest possible time is essential.
Here, a particular problem in the refurbishment of the iron skin is that the hot metal remaining in the furnace after the blow-off operation is solidified at the bottom of the furnace and remains in a large amount as a residue lump. Since the removal work of this lump is accompanied by great difficulty, the repair period is prolonged, resulting in an increase in repair costs and problems such as an increase in profits due to a decrease in production during the repair.

As a countermeasure against such a situation, an outlet for discharging residue (furnace bottom outlet) is provided below the normal outlet, and the molten iron is discharged from the furnace bottom outlet to the outside of the furnace.銑 "is performed.
Patent Document 1 adopts a method in which the discharged hot metal is received and conveyed by a torpedo car through the hot metal at the time of the furnace bottom pouring.
That is, in Patent Document 1, at least 4 months before the blowout, the monthly average minimum heating ratio 2.1 and the monthly average minimum hot metal temperature 1520 ° C. are maintained, and the furnace bottom temperature is within the same range as the past maximum temperature. The operation to maintain, the hot metal at the bottom of the furnace is kept in a molten state with low viscosity until the time of blow-off, the state where the solidified deposit thickness at the bottom of the furnace is 100 mm or less is stably maintained, A method of discharging the bottom of a furnace from a furnace bottom outlet provided on the furnace wall portion below the normal outlet at the time of blowout is disclosed.

  On the other hand, in Patent Document 2, when the blast furnace is blown off and repaired, the scale of the charge is reduced (the charge of the new charge is reduced or stopped during operation, and the charge in the blast furnace is reduced. When the stock level drops to the upper part of the tuyere, the additional coke is charged, followed by the high specific gravity loading filler such as silica and iron ore. A method is disclosed in which the core coke is allowed to settle in the hot metal and the molten iron is discharged while preventing the melting of the molten iron, thereby reducing the amount of residual lump.

  In Patent Document 3, when a blast furnace is blown off and refurbished, a charge is additionally charged from the top of the furnace, and the furnace core coke is settled in the hot metal by the load of the charge, and the furnace core coke and the hot metal In the method of reducing the residue at the time of blast furnace refurbishment, which increases the layer of the mixture, after starting the scale operation, the top surface of the charged material is changed from the stock line during normal operation to the vertical distance between the stock line and the tuyere. A method is disclosed in which an additional packing having a particle size of 20 mm or more is introduced from the time when the level drops to a level of 1/3 or more and 2/3 or less, and the furnace core coke is settled in the hot metal by the load of the packing.

JP 2006-137985 A JP 2003-301208 A JP 2001-348603 A

  However, when using the technology of Patent Document 1 and considering the operation of blowing up the blast furnace, if the position of the furnace bottom outlet is in a position that cannot be received by the existing torpedo car on the equipment layout, separately Measures such as whether to install a new torpedo pod or hot metal ladle with a lower height of the receiving port, or a new track that is deeper than the existing track, can be considered. Nonetheless, none of these measures can be adopted due to the problem of increased cost and construction period extension.

  In such a case, the hot metal discharged from the bottom of the blast furnace is discharged into a dry pit (also referred to as “slag pit”) through the firewood, solidified, then crushed and scrapped. Yes. However, the means for discharging the hot metal discharged from the furnace bottom to the dry pit is mostly used as a backup of the receiving by the torpedo car, and a method for discharging the entire amount of hot metal discharged from the furnace bottom to the dry pit from the beginning. In fact, there has been no concrete study so far. Even if Patent Document 1 is scrutinized, there is no disclosure regarding a technique for discharging the molten iron discharged from the furnace bottom into the dry pit.

Needless to say, Patent Documents 2 and 3 do not disclose or suggest a technique for discharging the molten iron discharged from the furnace bottom to the dry pit.
In summary, Patent Documents 1 to 3 disclose the means for reducing the amount of deposits on the furnace bottom and the amount of residue in the furnace, but the entire amount of molten iron discharged from the furnace bottom is discharged into the dry pit. In fact, there is no disclosure of specific means for processing.

  In view of the above circumstances, an object of the present invention is to provide a method of treating hot metal discharged from the blast furnace at the bottom of the blast furnace, which can reduce the cost of repair and reduce the repair period during blast furnace repair.

  The method for treating hot metal discharged from the blast furnace according to the present invention is to discharge the hot metal discharged from the outlet of the blast furnace into a “ground fixed dent” which is a dent fixed to the ground via the iron for brewing. In the hot metal processing method of processing the hot metal by solidifying the discharged hot metal in the ground fixing recess, a covering portion is provided in the ground fixing recess to cover the entire surface of the discharged hot metal. The hot metal is discharged into a ground fixing dent provided with the covering portion.

Preferably, the covering portion is a drainage roof for shielding water that pours into the ground fixing dent, and the drainage roof may be constituted by a roof body and a plurality of columns.
Preferably, the roof main body is installed at a downward slope toward the anti-blast furnace side.
Preferably, among the pillars, with respect to the pillars erected in the ground fixing recess, the lower part of the pillars may be surrounded by a refractory.

Preferably, among the pillars, with respect to the pillars standing in the ground fixing recess, the lower part of the pillars may be provided so as to stand on a refractory placed in the ground fixing recess.
Preferably, a refractory that is cylindrical in the ground fixing recess is erected in an upward-released manner, and among the pillars, a pillar that is erected in the ground fixing recess is a lower part of the pillar. However, it is preferable to provide a space in the inner peripheral surface of the refractory and the support column inside the cylindrical refractory in the standing state.

Preferably, a refractory basket that projects outward is attached to the lower end of the cylindrical refractory.
Preferably, sand is placed around the cylindrical refractory to which the refractory basket is attached.
Preferably, a dam made of sand is provided in the ground fixing dent to divide the ground fixing dent.

  Preferably, the whole or part of the dry pit is used as the ground fixing recess, and the roof body is installed at a position lower than a side wall surrounding the dry pit.

  According to the present invention, the hot metal discharged from the blast furnace is discharged into the ground fixing dent covered with the cover and solidified, so that it is possible to reliably prevent a steam explosion caused by contact between the hot metal and rainwater. . Therefore, the blast furnace can be repaired more safely and efficiently, and the repair period can be further shortened while further reducing the repair cost.

It is a top view explaining arrangement of a blast furnace and a dry pit concerning the present invention. It is side surface sectional drawing explaining the structure of the rainwater protection roof installed in the dry pit. It is plane sectional drawing explaining the structure of the rainwater protection roof installed in the dry pit. It is side surface sectional drawing explaining the installation structure of the lower part of a support | pillar, and a refractory. It is side surface sectional drawing explaining the installation structure of the lower part of a support | pillar, and a refractory. It is side surface sectional drawing explaining the installation structure of the lower part of a support | pillar, and a refractory. It is side surface sectional drawing explaining the state which installed the rainwater protection roof in the dry pit.

Hereinafter, an embodiment of a method for treating hot metal discharged from a blast furnace according to the present invention, particularly a method for treating hot metal discharged from a blast furnace bottom, will be described with reference to the drawings.
In addition, embodiment described below is an example which actualized this invention, Comprising: The structure of this invention is not limited with the specific example.
The blast furnace 1 is a vertical cylindrical furnace body that is arranged such that its axis is directed in the vertical direction, and the outside of the furnace body is covered with a steel plate-made iron skin. Is lined with refractory bricks. In the furnace body of this blast furnace 1, the upper end side and the lower end side in the vertical direction are narrowed more narrowly than the midway side, and the furnace body described above has a shaft portion, a straight barrel-shaped belly portion from the top, and further below it. It consists of a Bosch part that spreads upward and a hearth part at the bottom.

On the side wall of the hearth, openings (feathers) for blowing hot air and pulverized coal into the furnace are provided radially, and an outlet (normal outlet) for taking out pig iron (molten iron) is provided. Iron is produced every few hours from the port.
Although the blast furnace 1 has such a structure, the blast furnace 1 is periodically repaired or replaced because the refractory lining 6 or the furnace body cooling equipment deteriorates or breaks with long-term operation. Renovation to be carried out.

Refurbishment of the blast furnace 1 is generally performed after the hot metal remaining in the furnace is discharged after the transition from normal operation to reduced scale operation, hot air supply to the blast furnace 1 is stopped, water is injected into the furnace and cooled. Is called.
In the present invention, when the blast furnace 1 is blown up prior to the blast furnace 1 refurbishment, the hot metal discharged from the furnace bottom outlet 2 provided on the furnace wall portion below the normal outlet is used as the furnace. By discharging into the dent fixed to the ground (hereinafter also referred to as “ground fixing dent 4”) via the bottom culverting tub 3 and solidifying the discharged hot metal in the ground fixing dent 4 The present invention relates to a method for treating hot metal.

In particular, the ground fixing dent 4 installed in the vicinity of the blast furnace 1 is provided with a cover portion covering the upper opening of the ground fixing dent 4.
Furnace bottom outlet 2 used for blow-off operation is installed on the furnace wall part below the normal outlet on the side wall of blast furnace 1, but its height is not fixed, for example, it is installed at the bottom of the furnace. The amount of residue in the furnace may be determined to be as small as possible by estimating the wear state of the furnace refractory 6 using information such as the temperature sensor. For example, the furnace bottom outlet 2 is opened at the end of the scale-down operation (at the time of blow-off operation).

At the outlet of the furnace bottom outlet 2, a furnace bottom outlet rod 3 having a concave cross-section with the upper part above the opening is provided so as to be adjacent to the furnace bottom outlet 2.
It is necessary to receive the molten iron discharged from the furnace bottom outlet 2 and transfer it to the ground fixing recess 4 (furnace bottom outlet 3) at a lower position than when the normal outlet is used. Since there is no permanent use, it is possible to use a temporary installation, and the installation can be performed when the furnace bottom outlet 2 is installed.

  On the ground adjacent to the blast furnace 1, in other words, on the exit side of the bottom bottom dredging rod 3, a ground fixing recess 4 is formed by digging the ground into a concave shape. Usually, the slag discharged from the blast furnace 1 may be used as a slag pit (dry slag pit). The dry pit is a yard used to cool the molten slag discharged from the blast furnace 1 by pouring it in order to produce slowly cooled slag.

In the case of the present invention, the ground fixing dent 4 needs to take out and store the hot metal remaining at the bottom of the blast furnace 1 after blow-off from the furnace bottom outlet 2 and, for example, in the case of a 4000 m ³ class blast furnace 1 It is necessary to secure a volume of at least about 200 m ³ , preferably about 400 m ³ .
Further, the hot metal stored in the ground fixing dent 4 needs to be cut into small pieces after being solidified, and then carried out. In order to facilitate the cutting and carrying out operation, the depth of the hot metal stored in the ground fixing dent 4 is determined. Is limited to about 0.6 m, preferably about 0.3 m at the maximum. Accordingly, the width of the ground fixing recess 4 is at least a rectangular shape in a plan view of about 200 m ² , preferably a rectangular shape in a plan view of about 300 m ² , particularly preferably a rectangular shape in a plan view of about 600 m ^2. It is necessary to keep.

  In addition, if the distance from the furnace bottom outlet 2 to the ground fixing recess 4 is too long, it is necessary to lengthen the furnace bottom outlet 3 and the production cost of the furnace bottom outlet 3 increases. In addition to the excessive effort required to install the bottom 3 and the removal of the bottom 3 after completion of the bottom discharge, in addition to the bottom bottom There is a concern that the hot metal is solidified due to a decrease in temperature in the jar 3.

Therefore, it is desirable that the ground fixing recess 4 be installed as close to the blast furnace 1 as possible, and the shortest distance from the furnace bottom outlet 2 to the ground fixing recess 4 (approximately equivalent to the length of the furnace bottom outlet 3). ) Is, for example, preferably within 30 m, more preferably within 20 m.
Further, in the case of the present invention, a cover portion 5 that covers the entire upper surface of the hot metal discharged into the ground fixing recess 4 is provided in the ground fixing recess 4. In the case of this embodiment, this cover part is a drainage roof for shielding the water and rain water which pour into the ground fixing dent 4, and the cover part 5 may be called the rainwater protection roof 5 hereafter.

In the case of the present embodiment, the rainwater-excluding roof 5 includes a roof main body 51 and a plurality of support columns 52.
The repair of the blast furnace 1 is a large-scale repair and is performed according to a predetermined schedule unless there is a problem. For this reason, the blast furnace 1 may be repaired at a time when there is a lot of rain, such as a typhoon or a rainy season. In this case, there is a possibility that the bottom out of the furnace may have to be performed just during the rain or immediately after the rain due to the schedule of the blow-off schedule.

At this time, when the molten iron discharged from the furnace bottom is discharged to the ground fixing recess 4 through the furnace bottom discharging rod 3, it may come into contact with rainwater stored in the ground fixing recess 4 to cause a steam explosion. . In order to avoid such a trouble, the rain fixing roof 4 which covers the whole surface in advance is provided in the ground fixing dent 4 beforehand.
Hereinafter, a case where the entire dry pit is used as the ground fixing recess 4 will be described as an example, and a specific description will be given with reference to the drawings.

As shown in FIG. 1, the hot metal discharged from the furnace bottom outlet 2 of the blast furnace 1 is discharged into a dry pit 4 as a ground fixing recess 4 through a furnace bottom outlet 3. As shown in FIG. 2, a rainwater-excluding roof 5 that covers the entire surface of the pit 4 is installed in advance.
The rainwater protection roof 5 is preferably composed of a roof main body 51 made of an iron plate and a plurality of iron columns 52. The reason why both the roof main body 51 and the support column 52 are made of iron is to maintain the strength to withstand storms such as when a typhoon is approaching and to withstand the heat of the hot metal discharged into the dry pit 4.

  As an iron plate used for the roof main body 51, for example, a corrugated iron plate commonly used for a roof of a bicycle parking lot can be used. The roof body 51 may be horizontal or dome-shaped. Moreover, as the iron support | pillar 52, the scaffold pipe for construction can be used, for example. The number of iron columns 52 may be determined by a method commonly used by those skilled in the art in consideration of the weight of the roof body 51 and the pressure of wind and rain.

Thus, by using the ready-made iron member, not only the procurement cost of the member can be reduced, but also the time required for assembly and disassembly can be shortened.
As shown to FIG. 2A, it is preferable that the roof main body 51 is a substantially horizontal board | plate, and is installed in the descending slope to the anti-blast furnace 1 side. In other words, it is preferable to install it in a downward gradient in a direction away from the tip of the furnace bottom extraction rod 3. As a result, rainwater that has fallen on the roof body 51 flows from the blast furnace 1 side toward the anti-blast furnace 1 side, and flows down to the opposite side of the blast furnace 1, so that there is no risk of rainwater spilling on the side close to the blast furnace 1. There is no risk of steam explosion due to contact with hot metal.

The angle of the downward slope toward the anti-blast furnace 1 side of the roof body 51 prevents rainwater from flowing back to the blast furnace 1 side even in heavy rain, and the anti-blast furnace 1 side end of the roof body 51 is stored in the dry pit 4. In order to ensure a sufficient height from the hot metal surface, for example, it may be appropriately adjusted within a range of 1 to 10 °, more preferably 2 to 5 ° with respect to the horizontal plane.
Of the plurality of iron struts 52, the lower part of each of the iron struts 52 erected in the dry pit 4 is surrounded by the refractory 6, or, among the plurality of iron struts 52, disposed in the dry pit 4. It is preferable that the iron support 52 to be erected is erected on the refractory 6 placed in the dry pit 4.

  In order to support the weight of the roof main body 51 that covers the entire surface of the dry pit 4 having a large area, it is necessary to install a large number of the steel support columns 52. Installation on the surrounding concrete wall 9 or the like is not practical in terms of strength and cost. Of the total required number, it is inevitable that most of the number is installed in the dry pit 4.

  Thus, the lower part of the iron support 52 installed in the dry pit 4 is soaked in the high-temperature hot metal discharged in the dry pit 4 that there is a strong possibility of deterioration. Therefore, in order to prevent direct contact with the hot metal and suppress heat transfer from the hot metal, the inventors enclose the lower part of the iron support column 52 erected in the dry pit 4 with a refractory 6. Alternatively, an iron support 52 disposed in the dry pit 4 may be erected on the refractory 6 placed in the dry pit 4 or any structure may be employed.

When the iron support 52 to be placed in the dry pit 4 is erected on the refractory 6 placed in the dry pit 4, the lower end of the iron support 52 is placed on the upper surface of the refractory 6 as shown in FIG. 3C. For example, it may be fixed with an anchor bolt (not shown).
When adopting a structure in which the lower part of the iron support 52 standing in the dry pit 4 is surrounded by the refractory 6, even if the refractory 6 is applied so as to be in close contact with the lower part of the iron support 52, as shown in FIG. 3B. Although it is good, as shown in FIG. 3A, it is more preferable that the refractory 6 is formed into a cylindrical shape, for example, a cylindrical shape, and a space is provided between the inner peripheral surface thereof and the iron support column 52. The space preferably has a distance of about 5 cm or more.

  Thus, by providing a space, that is, an air layer, between the refractory 6 and the iron support 52, the heat insulating effect is increased, and heat transfer from the hot metal can be further suppressed. As a result, it becomes possible to make the thickness of the refractory 6 thinner than in the case where the construction is performed in close contact with the lower portion of the iron support 52, and not only the cost reduction effect by reducing the amount of the refractory 6 used is obtained, but also the fire resistance. The effect of reducing the transportation, installation and removal work of the object 6 can also be obtained.

The height of the refractory 6 may be determined by adding safety to the estimated maximum depth of the hot metal (for example, 1.5 to 2 times the estimated maximum depth, for example, about 0.7 m or more). Further, the thickness of the refractory 6 and the thickness of the air layer may be set so that the surface temperature of the iron support 52 is not more than a safe temperature (for example, 200 ° C.) that does not deteriorate the material by heat transfer calculation.
However, particularly when the weight of the refractory 6 is reduced, there is a concern that the refractory 6 is likely to float due to the specific gravity difference from the hot metal. Therefore, as shown in FIG. 3A, it is recommended to attach a square or round ridge 7 made of the refractory 6 projecting outward at the lower end of the cylindrical refractory 6. Then, by adjusting the amount of protrusion of the flange 7, the hot metal is solidified on the protruding portion of the flange 7, thereby preventing the lifting.

Of course, even when the refractory 6 is brought into close contact with the lower portion of the iron support 52 or when the iron support 52 is erected on the refractory 6, FIG. 3B and FIG. As shown in FIG.
Then, as shown in FIG. 4, the sand 8 is placed around the cylindrical refractory 6 to which the gutter 7 is attached, so that the lifting can be more reliably prevented by the weight. Although it does not specifically limit as the sand 8, For example, the casting bed sand 8 (river sand 8, particle size 250 micrometers or less) used in order to protect a normal brewing can be used.

  As shown in FIG. 4, the dry pit 4 is usually surrounded by a concrete wall 9 (side wall) on the three sides except the side farthest from the blast furnace 1 and the bottom surface is covered with a concrete floor 10. In order to protect the surface of the bottom concrete floor 10 from the molten iron, it is desirable to spread the sand 8 on the ballast. Thereby, hot metal can be prevented from reaching the surface of the bottom concrete floor 10 through the gap of the ballast layer.

  Furthermore, it is recommended that the roof body 51 be installed at a position lower than the concrete wall 9 surrounding the dry pit 4 as shown in FIGS. 2A and 4. Thereby, it becomes possible to avoid the trouble that strong wind blows from between the concrete wall 9 and the roof main body 51, and the roof main body 51 is blown up and destroyed. That is, it is possible to more reliably protect the rainwater-excluding roof 5 from strong winds due to typhoon approach.

Note that the concrete wall 9 surrounding the dry pit 4 is usually not installed on the anti-blast furnace 1 side in order to make it easy to carry out the solidified slag. It is only necessary to pile up the ballast and make the opening as narrow as possible.
Further, it is preferable that a dam (not shown) made of sand is provided in the dry pit 4 to divide the dry pit 4 into small sections.

  For example, as shown in FIG. 4, when sand 8 is placed around a cylindrical refractory 6 to which a gutter 7 is attached, the sand 8 is also raised between adjacent placed sands 8 to form a weir. And can be subdivided. As described above, the inside of the dry pit 4 is subdivided by the weirs of the sand 8 so that a cut or a dent is formed in the plate-shaped pig iron scrap after the molten iron discharged into the dry pit 4 is solidified. For example, a plate-like chocolate has a streak-like dent, which can be used to subdivide the chocolate.

  As a result, when taking out the plate-shaped pig iron scrap from the dry pit 4, it becomes easy to cut into small pieces, and the carrying-out work is greatly reduced. The height of the weir is adjusted so that the hot metal discharged into the dry pit 4 extends over the weir of the sand 8 and spreads throughout the dry pit 4, or a break is formed in a part of the weir. It should be provided that the hot metal flows from there to the adjacent subsection.

In the above embodiment, the refractory 6 is formed in a cylindrical shape when a space is provided between the steel support columns 52. However, the present invention is not limited to this, but an elliptical cylindrical shape, a triangular cylindrical shape, a rectangular cylindrical shape, a hexagonal cylindrical shape is used. Any shape may be used as long as the shape is a tube or an octagonal tube.
In the above embodiment, an example in which the entire dry pit is the ground fixing dent 4 and the rainwater-excluding roof 5 is installed on the entire surface is not limited to this, but the area of the dry pit 4 is sufficiently large. Alternatively, the rainwater-excluding roof 5 may be installed only in a part of the entire area of the dry pit 4, for example, a part having a constant area on the blast furnace 1 side, and this part may be used as the ground fixing dent 4. In this case, in order to prevent the hot metal from spreading to a portion not covered with the rainwater-preventing roof 5, for example, a ballast is further stacked on the boundary between the portion covered with the rainwater-preventing roof 5 and the portion not covered with it. It is good to build a weir with sand 8.

Next, an embodiment of a method for treating hot metal discharged from the blast furnace 1 according to the present invention will be described.
Specifically, the blast furnace 1 having an internal volume of about 4800 m ³ Upon that Tetsugawa diverted renovation, in September is typhoon season, one (length of about 60 m × width of about 17m × sidewalls of 4 There dry pit Discontinue normal use of (concrete wall 9) with a height of about 4m, and the discharged hot metal has a depth of about 0.6m), and the ballast and sand at a position about 30m in the length direction from the blast furnace 1 side In addition to installing a weir for damming hot metal, a rainwater-excluding roof 5 was installed in a portion extending from the blast furnace 1 side to a length of about 30 m so as to cover the entire width direction.

A commercially available corrugated iron plate is used for the roof main body 51 of the rainwater-excluding roof 5, and the descending slope is about 2.4 ° as the distance from the blast furnace 1 increases, and the uppermost end on the blast furnace 1 side is 0.75 m lower than the upper end of the concrete wall 9. It installed so that it might become a position.
Further, a commercially available scaffolding pipe (outer diameter 48 mm) is used for the iron support 52, and a cylindrical refractory 6 having a height of 700 mm, an outer diameter of 390 mm, and an inner diameter of 270 mm is formed in the lower part thereof, and a square is formed at the lower end of the cylindrical refractory 6. Then, a refractory 6 iron 7 having a side of 500 m and a thickness of 50 mm was attached and arranged in a lattice pattern at intervals of 2.4 m pitch in the length direction and 1.8 m pitch in the width direction in the dry pit.

The cylindrical refractory 6 and the square refractory casket 7 were produced as a single piece by pouring using a chamotte castable. Further, cast floor sand 8 (river sand) kneaded by adding water around the cylindrical refractory 6 to which the trough 7 was attached was placed.
In addition, in order to avoid contact between the hot metal and moisture, the refractory 6 containing moisture and the cast sand 8 were dried using a movable burner. In this embodiment, no sand 8 weir was provided for subdividing the dry pits for reasons of the repair period.

After that, after attaching the bottom 3 of the furnace bottom discharge, after the completion of the operation of the blast furnace 1, the bottom 2 of the furnace bottom is opened in the furnace wall part below the normal outlet, The hot metal taken out was received by the furnace bottom discharge iron 3 and discharged to the part where the rainwater-excluding roof 5 was installed in the dry pit.
As a result, the hot metal discharged from the bottom of the furnace spread at a substantially uniform depth over the entire portion of the dry pit where the rainwater protection roof 5 was installed, but problems such as floating of the cylindrical refractory 6 and damage to the steel support 52 were observed. Did not occur. In addition, there was a typhoon approach during the repair period, but the rainwater-exclusive roof 5 was intact.

  The hot metal solidified in the dry pit (plate-shaped pig iron scrap) was only about 30 cm thick, and there was still a sufficient margin in the depth of the dry pit. It was decided to recycle as a dry pit for ordinary slow cooling slag production. After the blast furnace 1 is re-fired, the slow-cooled slag can be produced with the dry pits without any particular problems.

In this way, regardless of the typhoon season, the blast furnace 1 can be blown up without any trouble according to the planned schedule, and after that, it is an unprecedented very short construction period of about 90 days. Renovation was realized.
In the embodiment disclosed herein, matters not explicitly disclosed, for example, operating conditions, various parameters, dimensions, weights, volumes, etc. of the components do not deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

1 Blast furnace 2 Furnace bottom outlet 3 Furnace bottom outlet 4 Ground fixing dent (dry pit)
5 rainwater protection roof (cover)
6 Refractory 7 鍔 8 Sand 9 Concrete wall 10 Concrete floor 51 Roof body 52 Iron support

Claims (10)

The hot metal discharged from the outlet of the blast furnace is discharged to the “ground fixing dent”, which is a dent fixed to the ground via the output pit, and the discharged hot metal is solidified in the ground fixed dent. In the hot metal processing method of processing the hot metal,
In the ground fixing dent, a cover that covers the entire surface of the discharged hot metal is installed,
A method for treating hot metal discharged from a blast furnace, wherein the hot metal is discharged into a ground-fixed recess provided with the covering portion. The covering portion is a drainage roof for shielding water that pours into the ground fixing dent,
The method for treating hot metal discharged from a blast furnace according to claim 1, wherein the drainage roof is constituted by a roof main body and a plurality of columns.   The method for treating hot metal discharged from a blast furnace according to claim 2, wherein the roof body is installed at a downward slope toward the anti-blast furnace side.   4. The hot metal discharged from the blast furnace according to claim 2, wherein the pillar is erected in the ground fixing dent, and the lower part of the pillar is surrounded by a refractory. 5. Processing method.   Among the pillars, with respect to the pillars standing in the ground fixing recess, the lower part of the pillars is provided so as to stand on a refractory placed in the ground fixing recess. The processing method of the hot metal extracted from the blast furnace of Claim 2 or 3. A refractory made cylindrical in the ground fixing dent is erected in an upward open state,
Of the pillars, with respect to the pillars erected in the ground fixing recess, the lower part of the pillars is located inside the tubular refractory in the standing state, the inner peripheral surface of the refractory and the pillars The method for treating hot metal discharged from a blast furnace according to claim 4, wherein a space is formed between the hot metal and the blast furnace.   The method for treating hot metal discharged from a blast furnace according to claim 6, wherein a refractory steel bar extending outward is attached to a lower end of the cylindrical refractory material.   The method for treating hot metal discharged from a blast furnace according to claim 7, wherein sand is placed around the cylindrical refractory to which the refractory firewood is attached.   The method for treating hot metal discharged from a blast furnace according to any one of claims 1 to 8, wherein a weir made of sand is provided in the ground fixing dent to divide the ground fixing dent.   The whole or part of the dry pit is used as the ground fixing dent, and the roof main body is installed at a position lower than a side wall surrounding the dry pit. Treatment method of hot metal discharged from blast furnace.

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