JPS6024306A - Calcining method of mud packed in tap hole of blast furnace - Google Patents

Abstract

PURPOSE:To sinter the mud packed in the tap hole of a blast furnace in short time and to prevent erosion during tapping by drilling the mud down to a suitable depth, inserting a heating element into the hole, heating and calcining the mud. CONSTITUTION:The top nozzle of a mud gun (not shown in the figure) is pressfitted into a mud gun fitting part 5 provided in a hearth part consisting of a blast furnace shell 1 and a body brick 2 and mud 4 is forced and packed into a tap hole 3 penetrating through the brick 2 and the mud deposit 6 in the furnace in the stage of ending the tapping operation with the blast furnace. The hole 3 is then drilled to within at least 0.5m length from the innermost end in the furnace by using a drill having a prescribed diameter prior to the next tapping operation. An electrode bar 7 as a heating element is inserted into the hole drilled by using said drill and electricity is conducted to the bar via a power source holder 8 from a power source device 9 to heat the bar to >=1,000 deg.C. The mud 3 around the hole is thus heated and calcined so that the sintering strength is developed in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for firing mud filling a blast furnace tap hole.

In recent years, the production capacity of ironmaking blast furnaces has increased from 5,000 to 10,000.
The number of taps per day reaches 10 to 18 times per day, and it is therefore necessary to open and close the tap hole every time the tap is tapped.

The structure of the hearth near the tap hole and the tapping method will be explained with reference to the longitudinal cross-sectional view of Fig. 1. The provided tap hole 3 is filled with mud 4. A mud gun crimping sliding part 5 is provided at the tap hole on the furnace shell side of the tap hole 3, and the tip nozzle of a mud gun (not shown) is crimped to this sliding part 5. Mud is press-fitted into the tap hole 3 by a plunger. The tap hole 3 passes through the furnace brick 2 and the mud deposits 6 in the furnace and reaches the molten layer in the furnace.

To start the tapping operation, the mud 4 filled in the tap hole 3 is drilled using a drill and a metal rod (not shown) until it reaches the inside of the furnace. Pig production starts, and when the molten metal and slag are extracted, the mud around the drilled hole becomes hot metal.

The diameter of the hole expands due to abrasion and erosion due to the flow of slag, and as the level of the shattered molten material in the blast furnace decreases, the furnace gas begins to be discharged from the tap hole. , making it impossible to continue tapping.

In this state, the tip nozzle of the mud gun is pressed against the mud gun crimping and sliding portion 5, and the mud in the mud gun is press-fitted into the tap hole 3 by the plunger to fill it, and the tapping operation is completed. The weight of the mud that is usually press-fitted is 200 to 3 ooxy, and the mud that overflows the inner end of the tap hole that penetrates the blast furnace body brick 2 becomes mud deposits 6 and becomes the inner end of the tap hole. It is in a state where it is deposited in the area. In a blast furnace with a tapage rate of 5,000 to 10,000 tons per day, the depth of the tap hole 3 formed through the furnace wall bricks 2 and mud deposits 6 is usually 3 to 4 m long. It is.

Now, when the Tachikawa pighole 3 is closed, the mud 4 filled in the taphole 3 is dried by the heat retained in the furnace body and the heat transferred from the high-temperature furnace inner nozzle, but it is sufficiently dried and fired. Usually 1 to 2 hours are required for the steel to harden and be ready for the next tap.

FIG. 2 is a diagram showing an example of the relationship between the depth of the tap hole and the temperature of each part of the tap hole corresponding to each depth, that is, the temperature gradient depending on the depth of the tap hole.

According to the figure, the temperature is about 1100 C or less within the tap hole depth of 3.0 m. But 1100 tr
At temperatures below, the mud 4 filled in the tap hole 3 will not sinter and develop sufficient strength.

For this reason, the actual mud used is 1000 to 12
Currently, refractories are used that exhibit a certain degree of firing strength within a temperature range of 0.00 tr. However, such mud has low fire resistance, so
0 C・When it comes into contact with the hot metal and slag before and after, it is easily eroded and the tap hole diameter expands during tapping.

In order to avoid such melting damage in the tap hole, a high gauze surface (assuming that a large piece of metal is used as mud) has sufficient fire resistance at around 1500 C, which is the temperature at which hot metal and molten slag are tapped. This mud is not fired while it is being filled in the tap hole, so it does not develop strength, and when tapped, it reaches 150
Even if it comes into contact with hot metal and slag at around 0 C, there is not enough time for the mud to be fired, so the mud is worn away by the flow of tapped metal in an unfired state, and the diameter of the tap hole expands.

As mentioned above, there is a natural limit to the ability of the mud to maintain good tapping conditions without being worn or eroded even when it comes into contact with hot hot metal or slag, and there are limits to this. After a certain amount of tapping and slag has been performed, or after tapping and slag for a certain period of time, it is necessary to press-fill the tap hole with new mud, close it, and restart the tap operation. There is. Furthermore, as mentioned above, according to the conventional method, the mud is not fired within a short time after the taphole is closed, so that the next taping cannot be performed, which is extremely inconvenient for blast furnace operation.

The present invention addresses the drawbacks of blast furnace tapping operations according to the prior art.

In particular, it eliminates the disadvantages and inconveniences of tapping work caused by poor firing of the mud filled into the blast furnace taphole.

The purpose of the present invention is to provide a method for firing mud that fills the tap hole of a blast furnace, which can be improved by using a drill of a predetermined diameter before tapping the mud filled in the tap hole of the blast furnace. The innermost end of the tap hole in the furnace is at least 0.5
After drilling a hole with a length of m so that mud remains without being drilled, a 100 m long hole is drilled using the drill.
A method of firing mud for filling a blast furnace tap hole, which is characterized by inserting a heating element capable of heating over 0 t:', and heating and firing the mud around the drilled hole with the heating element. The above objective can be achieved by providing the following.

Next, the present invention will be described in detail.

The present inventors found that during tapping, the diameter of the tap hole expands due to wear and erosion, and gas in the furnace begins to be discharged from the tap hole, making it difficult to continue the tapping operation. What is the disadvantage of having to press mud into the tap hole, stop tapping, and then start the tapping process again? Various studies were conducted to remove and improve the problem.

One of the main causes of the above defects is that the mud filled in the tap hole is not sufficiently fired. Mud in the relatively deep part of the furnace is fired and sintered in a short time because the surrounding furnace temperature is high, and its strength is developed, but mud on the side of the furnace shell of the tap hole has a low surrounding furnace temperature. Therefore, the strength of the mud is not developed because it is not fired or sintered in a short time.
For this reason, Shimarad is easily worn out by the flow of hot metal and slag.
Focusing on the fact that this is the main cause of the expansion of the tap hole diameter and the discharge of gas in the furnace as a result of melting, The present invention was completed based on the idea that fire resistance can be developed in a short period of time by promoting di-firing and sintering by heating.

According to the present invention, prior to tapping, the tap hole is drilled from the tap hole with a drill of a predetermined diameter so that the mud at the deepest part of the tap hole remains at least 50 cm long, and the hole is drilled in this way. By inserting a heating element, such as a carbon electrode rod for high-temperature heating, into the drilled hole and heating and firing the mud around the electrode rod to a temperature of 100 C or more, the mud is sintered and develops strength. The flow of slag greatly reduces the rate of wear and erosion. 1. According to the conventional method, the mud filled in the shell side of the taphole, that is, the part close to the taphole, is
Since the firing was inevitably insufficient, we had no choice but to use mud with low fire resistance that can be easily fired at low temperatures.
Such mud with low refractoriness has a drawback of low corrosion resistance against hot metal and molten slag. However, according to the present invention, since the heating element is inserted and heated, the mud is sufficiently sintered and turned into hot metal.

It has greater corrosion resistance against slag, and can be sufficiently fired and sintered even when using high-grade refractories with high refractory properties as mud, significantly suppressing the expansion of the tap hole diameter during tapping. By being able to do so, it is not only possible to continue tapping the iron for a long time, but also to reduce the amount of labor in front of the blast furnace and to maintain smooth furnace conditions.

Next, one embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a vertical cross-sectional view of the hearth near the tap hole of the blast furnace, cut along the axis of the tap hole, and the mud 4 filled in the tap hole 3 according to the present invention is A hole is drilled with a drill of a predetermined diameter, leaving the innermost part of the hole 3, and a carbon electrode rod 7 for high temperature heating is inserted into the hole thus drilled. Electrode rod 7
is held by an electrode holder 8, and when the electrode rod 7 is energized from the power supply 9 through the electrode holder 8, the electrode rod 7 generates heat and its temperature rises to 1100 C or more. The temperature of this electrode rod can be adjusted by controlling the voltage. This carbon electrode rod becomes red hot in the taphole when energized, but the taphole is filled with non-oxidizing gas that permeates through the furnace body and leaks into the taphole. Prevents burnout due to oxidation.

In addition to carbon-based heating electrodes, it is also possible to use silicon carbide-based electrodes, or electrodes made of these materials coated with a heat-resistant metal. You can also use your body.

According to the present invention, as described above, the mud filled in the tap hole can be heated and fired using a carbon electrode rod, etc., so it has high corrosion resistance against hot metal and slag, and has a high refractory level. High grade refractories can be used as the mud material, which significantly increases the service life of the taphole refractories.

According to the present invention, in addition to the above-mentioned high-temperature heating element, the inside of the tap hole can be heated by a gas burner or an oxygen-gas burner, but when using a roaring burner, the atmosphere is controlled so as not to create an oxidizing atmosphere. It is advantageous to do so.

According to the present invention, it is possible to use a mud having a higher degree of fire resistance than conventional muds. An example of a conventional mud and an example of a mud that can be advantageously used according to the present invention are shown in the first example.
Shown in the table.

As shown in Table 1, the mud filled in the taphole is
Conventionally, it was necessary to use mud made mainly of refractories with low refractory properties because it was not possible to obtain the sufficient temperature necessary for firing, but according to the present invention, the temperature required for firing the mud can be lowered. Since it can be obtained arbitrarily and easily, it is possible to advantageously use a mud that has a high At203 content and high resistance to erosion against hot metal and slag. That is, according to the present invention, by performing mud firing in the taphole in a temperature range of 1250 to 1300 C, it is possible to obtain mud strength that is advantageous for the taphole slag action.

In a blast furnace that has conventionally been operated with a 14W daily tapping frequency, by using the present invention, the number of tappings can be reduced to 7 to 8 times/day.
decreased by the day. During the tapping operation, it is necessary to take out the hot metal and molten slag appropriately and always work so that the amount of molten material remaining in the furnace is minimized. It became possible to use high-grade refractories with high refractory properties, the range of materials that could be used for mud was expanded, tap hole management became easier, and blast furnace productivity improved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the hearth of the blast furnace, Fig. 2 is a diagram showing the relationship between the depth of the blast furnace tap hole and the temperature of each deep part,
FIG. 3 is a longitudinal sectional view showing one embodiment of the present invention taken along a tap hole in the hearth of a blast furnace. 1...Blast furnace shell shell, 2...Furnace ridge tile, 3...Tapping hole, 4...Mud, 5...Mud gun crimping sliding part, 6...Furnace with mud Kimono, 7...electrode rod, 8.
...electrode holder, 9...power supply device. Patent applicant: Kawasaki Steel Co., Ltd. Representative patent attorney Village 1) Politics

Claims (1)

[Claims] 8. Before tapping the mud filled in the tap hole of the blast furnace, use a drill of a specified diameter to remove the mud for at least a length of 5 m from the back end of the tap hole inside the furnace. After drilling the hole so that it remains unopened, a heating element capable of heating to 1000 t:' or more is inserted into the hole drilled using the drill, and the mud around the drilled hole is removed. A method for forming a Q11i blast furnace taphole filling mud, which is characterized by heating and firing with a heating element.