JPS589904A - Discharging method for content of blast furnace - Google Patents

Abstract

PURPOSE:To perform quenching and discharging simultaneously by blowing out a blast furnace after reducing the contents therein down to the height of tuyeres and moving the contents in the blast furnace to a water discharge port by injection of cooling water. CONSTITUTION:A water injecting port 6 is drilled in the part of the wall 3 of a blast furnace slightly below tuyeres 2, and a discharge hole 10 for content 1 in the blast furnace serving also as a water discharge port is provided in the lowermost part of the wall 3 on the side opposite from the port 6. The content 1 is reduced down to the height of the tuyeres 2 and the blast furnace is blown out in this state. When the gravity outflow of the content 1 through the hole 10 ceases, highly pressurized water is injected to the content 1 through the port 6 by a highly pressurized water injecting device 12 to cut the content 1 while quenching the same, thereby moving the entire part toward the hole 10. The content 1 deposited around the hole 10 is scraped to the outside of the furnace with a bulldozer 13 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for discharging the contents of a blast furnace, which is effective in shortening the refurbishment period of a blast furnace.

When renovating a blast furnace, it is necessary to discharge the contents of the blast furnace to the outside of the furnace. Conventionally, this method involves sequentially replacing the contents of the blast furnace with coke and ballast, at a normal charge level (
A common method was to stop the blowing at the top of the shaft, then spray cooling water onto the substituted material, and then scrape out the entire amount of the substituted material. However, this method requires time and effort to scrape out the contents of the blast furnace, leaving major problems in terms of construction time and cost.

Therefore, recently, as shown in Fig. 1(a), the blast furnace contents (1) are lowered to the height of the tuyere (2) without replacing them with coke and ballast during operation, as they are normally. At this stage, the so-called reduced-scale blowdown method is often adopted to stop blowing, and the blast furnace contents (1) such as red-hot coke, semi-molten pig iron, and slag remaining in the lower part of the furnace are usually removed from the furnace by the following two methods. Expelled outside.

■ The coke is naturally combusted, and the contents of the blast furnace (1) are reduced to 10
After cooling to below 0°C, a discharge port is made in the furnace wall (3) and the contents of the blast furnace are scraped out of the furnace.

■ The contents of the blast furnace (1) are forcibly cooled by water spraying from above, and then a discharge port is made in the furnace wall (3) and scraped out of the furnace.

However, the method (2) requires a period of storage ranging from six months to one year, and has the problem of significantly extending the period for repairing the blast furnace. On this point, method (①) removes the blast furnace contents (1) by
The process of scraping is started after forcibly cooling down, which is safe and takes only 1 to 3 days, but on the other hand, the cooling water accumulates in the furnace and degenerates into bricks (especially carbon bricks) at the bottom of the furnace. , embrittlement, spalling, etc. occur, which then necessitates replacement. Therefore, the forced cooling method described in (2) does not have as great an effect as expected from the perspective of the entire renovation work period.

The present invention aims to provide a method for discharging the contents of a blast furnace, which solves the above-mentioned problems in the forced cooling method and makes it possible to significantly shorten the period of blast furnace refurbishment.

Generally, the hearth of a blast furnace is as shown in Figure 1(a).
Carbon bricks (4) are placed in the lower and side layers, and chamotte bricks (5) are piled up inside.

Chamotte bricks (5) are severely damaged when the blast furnace is refurbished, so there is little point in reusing them, but carbon bricks (4), especially the lower layer so-called hearth bed bricks, are chamotte bricks (5). Since it is covered with water, there is almost no damage, and as long as it is not immersed in cooling water, it is considered that reuse is possible. In the past, no consideration was given to the reuse of used bricks, including carbon bricks for the hearth lining, but Brick Cost says that if it becomes possible to reuse even just the hearth lining bricks. However, it is not hard to imagine that significant results will be obtained in terms of the renovation period.

Based on the premise that the use of cooling water is essential for safely discharging the contents of a blast furnace in a short period of time, the present inventors have developed a method for protecting carbon bricks from being immersed in cooling water. I did a lot of research.

As a result, as long as the cooling water that is injected into the blast furnace contents is drained out of the furnace one by one and care is taken to prevent the cooling water from accumulating inside the furnace, even if cooling water is injected into the furnace, the bottom of the furnace will be covered. It has been found that the carbon bricks are reliably protected from immersion in cooling water, making it possible to reuse the carbon bricks at the bottom of the dead furnace.

The present invention has been made based on the above, and after the contents of the blast furnace are lowered to the level of the tuyere and the blast is stopped, a water injection hole can be bored in a portion of the furnace wall slightly below the tuyere, and the water injection A discharge hole for the blast furnace contents, which also serves as a drainage hole, is drilled at the lowest part of the furnace wall on the opposite side of the hole, and by injecting high-pressure water into the blast furnace contents from the water injection hole, the injected water is sequentially removed from the furnace through the discharge hole. The gist of the present invention is a method for discharging blast furnace contents, in which the contents of the blast furnace are moved to a discharge hole while flowing out of the furnace, and then the contents of the blast furnace are scraped out of the furnace.

Hereinafter, the method of the present invention will be explained in detail based on FIGS. 1(a) to (C).

First, as shown in FIG. 1(a), the contents of the blast furnace (1) are lowered to the level of the slats (2) in an operating state, and the blast is stopped at this stage.

After the blow-off is stopped, a water injection hole (6) is opened in the part of the furnace wall (3) slightly below the tuyere (2), as shown in Figure 1 (b).
I can wear it. If this hole (6) is too low, the blast furnace contents (1) will overflow during drilling, so the tuyere (2) and hearth bottom (7)
), and usually the tap hole (8) (see Fig. 1(a)) is selected because it is easy to drill.

As the name suggests, cooling water is injected from the water injection hole (6), but before this, a crawler drill (9) etc. is inserted into the blast furnace contents (1) to check whether there is residual pig iron or not. It is preferable to detect the amount to ensure safety when drilling the discharge hole QO.

On the other hand, a discharge hole αO for the blast furnace contents (1) can be bored at the bottom of the furnace wall (3) on the opposite side from the water injection hole (6). This hole 0
Since the hole 1 also serves as a drain, it is preferable to make it a smooth inclined hole that gradually descends from the height of the furnace bottom (7) as it goes outside the furnace, as shown in the figure. Also, when drilling holes, it is necessary to be careful not to damage the carbon brick bottom of the hearth.

There is no regulation that requires the water injection hole (6) and the discharge hole QO to be drilled first, but generally speaking, the water injection hole (6) and the discharge hole QO must be bored first.
) should be drilled first, followed by the discharge hole QO.

Blast furnace contents that naturally flowed out during drilling of discharge hole 00 (1)
is extinguished and cooled using fire extinguishing equipment 0η installed outside the furnace.

When the natural outflow from the discharge hole QO stops, the next step is as shown in Fig. 1 (C).
As shown, the high pressure water injection device (6) is inserted from the water injection hole (b).
High pressure water is injected into the blast furnace contents (1) at
1) is collapsed into a pile while extinguishing and cooling, and the whole is moved to the outflow hole 00. The high-pressure water injected into the blast furnace contents (1) sequentially flows out of the furnace through the discharge hole 00 and does not accumulate in the furnace.

When the blast furnace contents (1) gather at the discharge hole α0, they are finally scraped out of the furnace using a bulldozer or the like and transported. The bulldozer-Q field is of a special type equipped with a heat-resistant arm of sufficient length to scrape the blast furnace contents (1) out of the furnace.

In addition, the contents of the blast furnace (1
) is extinguished and cooled in the fire extinguishing equipment αη and removed in advance together with the extinguished contents of the natural outflow.

Table 1 shows a, b, c, d in Fig. 1(C) after the blast furnace contents are discharged by the above method in A blast furnace.
``This shows the results of a property investigation of the carbon bricks at the bottom of the furnace at four locations.The capacity of the blast furnace contents (1) is:
Immediately after blowing down, the area was estimated to be 600 m'', and the cooling water used to extinguish and move the fire had a pressure of more than 15%, and the amount of water was 80 to 100 tons. Each size is 3000fi width x 33001
It was 01 high, 3500cm wide x 3500+a high.

Table 1 also lists the typical property values of the above-mentioned furnace bottom carbon bricks.Although the furnace bottom carbon bricks after the blast furnace contents have been discharged by the above method also show some deterioration in properties, they are not practical. suppressed to a range without mastication, at least 1 minute
It is judged that it can withstand the use of the furnace.

As is clear from the above description, the method of the present invention is not only effective in forcibly extinguishing and cooling the blast furnace contents with cooling water and shortening the period required for cooling, but also cooling the carbon bricks in the bottom of the furnace. This has the effect of greatly shortening the cost and period of blast furnace renovation by protecting it from immersion in water and omitting the cost and construction period required to replace the carbon bricks at the bottom of the furnace.

Furthermore, since the method of the present invention moves the contents of the blast furnace to the discharge hole by jetting cooling water, it is extremely easy to scrape out the contents with a bulldozer or the like, and in this way, the contents of the blast furnace can be extinguished and cooled at the same time. Another major feature of the method of the present invention is that it performs the following steps.

[Brief explanation of drawings]

FIGS. 1(a) to 1(C) are longitudinal cross-sectional views showing step-by-step an example of the method of the present invention. In the figure, 1: blast furnace contents, 2: tuyere, 3: furnace wall, 4: carbon brick, 5: chamotte brick, 6: water injection hole, 7:
Hearth bottom, 8: Tapping port, 9: Crawler drill, 10: Discharge hole, 11: Fire extinguishing equipment, 12: High aqua regia injection device Continued from page 1 0 Inventor Junji Kariya Kashima Town, Kashima District, Ibaraki Prefecture 3 Oaza Hikari Kashima Steel Works, Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] (1) After lowering the contents of the blast furnace to the level of the siding and stopping the blast, a water inlet can be drilled in the part of the furnace wall slightly below the tuyere, and at the lowest part of the furnace wall on the opposite side from the water inlet. First, a discharge port for the blast furnace contents, which also serves as a drain port, is drilled, and by injecting high-pressure water into the blast furnace contents from the water injection hole, the blast furnace contents are discharged while the injected water sequentially flows out of the furnace through the discharge hole. A method for discharging blast furnace contents, which comprises moving the blast furnace contents to a hole and then scraping the blast furnace contents out of the furnace.