JPH0459905A - Method for opening iron tapping hole in blast furnace - Google Patents

Abstract

PURPOSE:To complete opening of an iron tapping hole in a blast furnace in a short time by connecting a ceramic pipe, having a structure which makes oxygen injecting velocity to be >= the sound velocity, to the tip part of an oxygen lance and injecting said oxygen. CONSTITUTION:A steel bar 9 is buried in the iron tapping hole 2 arranged at an iron shell 1 in the blast furnace as a metal bar. The ceramic pipe 11 having Laval-shaped tip nozzle connected to the tip part of the oxygen lance 6 fitted to a hole opening machine 3 is abutted on the steel bar 9 and mud 10, and said oxygen is fed from an oxygen lance supporting pipe 7. By injecting said oxygen from this ceramic pipe 11 at the sound velocity or more, the steel bar 9 is oxidized to generate heat, and the temp. thereof is made to >=700 deg.C and the steel bar is melted to execute opening of the iron tapping hole 2. At the time of melting the steel bar 9 by injecting said oxygen from the ceramic pipe 11, even if there is some consumption in the ceramic pipe 11, a very short advance of the oxygen lance 6 can achieve the purpose by using a drifter 5 in the hole opening machine 3, and the hole opening work to the iron tapping hole 2 can be completed only with stroke of the drift 5 in the hole opening machine 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for opening a taphole in a blast furnace. The present invention relates to a method for opening a tap hole in a blast furnace, which allows the tap hole to be opened in a short time.

Conventional technology In a blast furnace used for producing pig iron, when tapping molten pig iron, a drill is used to drill through the tap hole, which is blocked with plugging material (filling mud). This method has been used for many years, but as blast furnaces have become larger and the number of times of tapping has increased, people have begun to consider ways to shorten the time required for hole-opening operations, and various hole-opening methods have been developed.

For example, when closing a taphole, a metal rod (hereinafter referred to as a steel rod) is buried in the plugging material inside the taphole, and when the hole is opened, a WI element lance is used to prevent There is a hole-opening method in which a steel rod buried in the taphole is melted to open the hole. This method has the advantage of being able to use an existing taphole drilling machine, but! ! There is a problem in that the all prime lance used during elementary hole drilling is consumed together with the steel rod left inside the taphole to be melted, and the means for replenishing the consumable oxygen lance is now being replaced by an ell.

In addition, in applying this method to actual pressure, the operator must send oxygen into the taphole from the M source in front of the taphole, which also poses the following problem.

In other words, with this method, (1) scrubbing is scattered from the taphole during or immediately after drilling, creating a poor working environment for workers; and (2) the oxygen lance is not installed from the side of the taphole, rather than from the front. Since the oxygen lance is bent to fit into the tap hole, there is a risk that the oxygen lance will not fit straight into the tap hole and the hole will open out of alignment with the designated tap hole. An oxygen lance of 20 to 30 m is required, and the work involved in joining the oxygen lance with a joint is high.
4) It was difficult to judge whether to feed the oxygen lance, and there were problems such as the inability to perform hole-opening operations using appropriate feeding operations.

Therefore, Japanese Patent Application Laid-Open No. 156210/1982, 156211/1982, and Japanese Patent Application Laid-Open No. 62-1982 have proposed taphole opening technology using a consumable oxygen lance that solves these drawbacks.
As shown in Publication No. 1156212, Matt and jJ
J! In the method of melting the installed steel bar with an oxygen lance and opening the tap hole, the surface (0
There is a method for opening a tap hole in which an oxygen lance made of a colorized steel pipe having an Fe-A1 alloy of .

However, these techniques consume a lot of the oxygen lance, and require equipment such as a bend straightening device or a swivel arm to wind the oxygen lance onto a winding drum and straighten the bend during use. It becomes a place. In addition, in a conventional blast furnace, mechanical devices such as a hole drill, mud gun, and crane are placed in front of the tap hole, and a winding drum and straightening device, etc., for feeding out the M-thickness are installed. is difficult due to layout.

In order to solve the above-mentioned problem of the consumable oxygen lance, when opening the tap hole while abutting the oxygen lance against a steel rod that has been buried in the taphole plugging material and melting the steel rod, Alloy steel pipe, for example 5% Cr or more or 5% or more Cr and N+
Some use non-consumable oxygen lances that use 5% or more alloy steel as oxygen lances.

Such a non-consumable P drain meets the necessary conditions to efficiently drill a steel rod buried in the tap hole using oxygen.
In other words, (1) the oxygen lance must maintain its straightness even if it burns and melts, and has physical properties that allow it to plunge into the eight pig holes at a predetermined angle; (2) the oxygen lance has little wear and tear; (3) ) The oxygen lance must not be damaged, broken, or bent, and (4) the Itl element lance can be used with existing equipment.

However, even if the non-consumable oxygen lance made of Ni-Cr alloy steel is used, melting damage does not occur, and according to online experiments of tapping hole opening work, melting loss occurs after one tap operation. It was found that the length ranged from 2 to 7 m, with an average length of 5 m, and even times.

If an attempt is made to automate the tap hole drilling work under such lance erosion, a large-scale device equipped with ancillary devices such as a vibrator winding device will be required. The main point is that in order to open a tap hole using a simple device that does not require any additional mounting surface, it is desirable to reduce the amount of erosion at one time to 2 m or less.

As a result of repeated research to solve the above problem, the inventors of the present invention first opened a blast furnace taphole using only the trigger function of the taphole opening machine using an A-type screw with less corrosion damage. A method for opening the taphole of a blast furnace was proposed. In other words, j! ! In this method, a blast furnace taphole is opened by contacting an elementary lance with an installed metal rod and injecting oxygen to melt the metal rod. A ceramic pipe is connected to the tip of the oxygen lance, and the ceramic pipe is The VI feature is to open a tap hole by injecting 1 ul 1 vote onto a metal rod through a metal rod and melting the metal rod.

Ceramic is generally a material with very good erosion resistance, but it is relatively weak against thermal shock, so silicon nitride 60-9, which has high thermal shock resistance, is especially suitable for ceramic pipes.
A mixture of 5wt% and thermal shock-resistant boron nitride of 5~40w↑% is preferable, and a ceramic pipe protected by a metal outer tube fitted around the outer periphery is preferable. is preferable, and has the advantage that the outer circumferential surface of the metal outer cylindrical body can be protected by colorizing treatment or ceramic spraying.

However, if the ceramic pipe connected to the tip of the oxygen lance has a normal pipe shape, the shape of the column on the nozzle exit side where oxygen is injected is straight, so the oxygen ejection speed will be at the speed of sound. There was a problem in that the hole drilling work took a long time due to the lack of absolute oxygen supply and the lack of oxygen velocity energy given to the metal rod buried in the tap hole.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned problems, and specifically, to provide a ceramic pipe having a structure that not only supplies the necessary amount of oxygen but also allows the oxygen ejection speed to exceed the speed of sound. The object of the present invention is to propose a method for opening a blast furnace tap hole in which the opening of the blast furnace tap hole can be completed in a short time by connecting the tip of the M-spring and injecting oxygen.

Means for Solving the Problems and Their Effects Namely, the present invention provides a method for tapping iron in a blast furnace by bringing an oxygen lance into contact with a metal rod buried in a taphole plug in advance and injecting oxygen to melt the metal rod. In the method of opening the opening, a ceramic pipe with a Laval-shaped tip nozzle is connected to the tip of the oxygen lance, and P is injected onto the gold WA rod through the ceramic pipe to melt the metal rod and eject it. The feature is that the pigtail hole is drilled.

Hereinafter, the configuration and operation of the means of the present invention will be explained as follows.

The present inventors connected a ceramic pipe to the tip of the oxygen lance proposed earlier, and injected oxygen to metal rods such as steel rods in the blast furnace taphole to melt and open the steel rods. Since the hole-opening method takes one hour to open the hole, we conducted research and development on a method to shorten the hole-opening time. It was found that the oxygen ejection velocity should be set at or above the speed of sound.

Further research was conducted, and the present invention was established based on this research.

According to the present invention, at the start of the taphole drilling operation, a ceramic pipe with excellent melting resistance and a laval tip nozzle shape connected to the tip of the oxygen lance is placed in the taphole blocking material in advance. Since it comes into contact with a buried metal rod and injects oxygen, I! As the cable is sufficiently supplied, the oxygen ejection speed becomes higher than the speed of sound, and the hole-opening work is completed in a short time, making it possible to reduce melting and damage of the oxygen lance.

The ceramic pipe used in the present invention has a laval-shaped tip nozzle with a tapered or widened shape. Specifically, the ceramic pipe has a structure consisting of a tapered nozzle so that the flow path area is smoothly and appropriately reduced. The nozzle has a minimum area area called the throat, and the minimum area area of the mouth increases in the direction of the outlet from the side of the R road surface. It is. In this way, when a laval-shaped ceramic pipe with a tapered or wide-spread nozzle tip is used for oxygen injection, the tapered nozzle maintains the inlet pressure constant and lowers the back pressure. The flow rate gradually increases until the speed slows down to the speed of sound, and even if the back pressure is lowered beyond that point, neither the speed nor the flow rate will increase. On the other hand, in the case of a wide-end nozzle, once the flow velocity at the throat reaches the sonic velocity, the flow rate does not increase any further, similar to the case with a tapered nozzle. With a wide-end nozzle, if the back pressure is further reduced, supersonic speed can be achieved. In this case, when the back pressure is determined by the divergence rate of the divergent portion, that is, the area of the nozzle exit, a completely expanded and determined supersonic jet can be obtained. Therefore, if a laval-shaped ceramic pipe with a nozzle structure of tapered or wide-end type is installed at the tip, the shortage of oxygen supply will be resolved, and the oxygen jet speed will be higher than the speed of sound, completing the hole opening in a short time. can do. These Laval-shaped ceramic pipes with a medium-wide-end nozzle structure are preferable because the oxygen JII injection velocity and the like can be changed. Silicon nitride and nitride IS having the above composition ratio as a ceramic pipe
When a material having a composition of 1 is used, it has good machinability and does not crack due to thermal shock or mechanical impact, so the service life can be extended. Here, the silicon nitride is 60 to 95 wt%, nitride i#] 15 to 4
The reason for setting it to 0 wt% is as follows.

Silicon nitride has high thermal shock resistance and is an excellent material in terms of strength, but it has problems in the generation of heat cracks and difficulties in processability. On the other hand, boron nitride has the advantage of being resistant to thermal shock due to its good heat transfer coefficient, and in order to improve the above-mentioned problems and n points of silicon nitride, it is necessary to contain at least 5 wt% or more of boron nitride. .

By adding this 5wt%, heat cracks can be significantly reduced, and cutting processing is also possible.For example, the nozzle shape can be made into a rubber-like ceramic lubricant, and furthermore, the nozzle shape can be made into a laval-shaped ceramic lubricant. Cutting can also be done easily. In addition, the addition of boron nitride is also
If it exceeds 096, the strength will decrease and wear will be accelerated, so
A composition with a content of 0% or less is desirable.

As mentioned above, in order to improve the drawbacks of silicon nitride, boron nitride is blended in a range of 5 to 4 Qwt%, so as a result, silicon nitride is blended in a range of 60 to 5 Qwt%.

Furthermore, if a ceramic pipe is protected by fitting a metal outer cylinder around its outer periphery, it may break during the taphole opening process, leaving the ceramic pipe inside the taphole and hindering the tapping process. ~ You can get rid of your love feelings.

NCr-based alloys with excellent heat resistance are suitable for the metal outer tube, and if the outer peripheral surface of the metal outer tube is calorized or ceramic sprayed, the tap hole opening will be more stable. It becomes possible to perform work.

Hereinafter, the apparatus used when carrying out the method of the present invention will be explained based on the drawings.

In addition, FIG. 1 is an explanatory diagram showing the implementation status of the taphole opening work according to the present invention, and FIGS. 2 (a) and (b) show the structure of the oxygen lance used when implementing the present invention. (a) is a cross-sectional view, (b) is an enlarged cross-sectional view of the circled part in (a), and Figures 3 and 4 respectively show the structure of the oxygen lance used in the present invention. FIG. 4 is a cross-sectional view showing different aspects.

Reference numeral 1 is the blast furnace shell, 2 is the taphole, 3 is the hole drill, 4 is the drill support, 5 is the drifter, and 6 is! ! 7 is an oxygen lance branch pipe, 8 is a valve, 9 is a steel rod, 10 is mud, and 11 is a ceramic pipe connected to the tip of the IIIi lance 6.

First, as shown in Figures 1 and 2 (a), a steel rod 9 is buried as a metal rod in the tap hole 2 provided in the blast furnace shell 1, and the steel rod 9 and mad 10
On the other hand, a ceramic pipe 11 having a Laval-shaped tip nozzle connected to the tip of an oxygen lance 6 attached to the hole drilling machine 3 is brought into contact with the ceramic pipe 11 to supply oxygen from the oxygen lance branch pipe 7, and from this ceramic pipe 11. The steel rod 9 is oxidized and heated by the W1 element injected by a Matsuha 1.6 at a speed higher than the speed of sound, for example, and melted at a temperature of about 700°C or higher! ! Then, the tap hole 2 is opened.

Even if there is some wear on the ceramic pipe 11 when melting the steel rod 9 by suppressing oxygen from such a ceramic pipe 11, the oxygen lance 6 is slightly advanced using the drifter 5 with the opening 1fi3. The drilling work of the tap hole 2 can be completed only by the stroke of the drifter 5 of the hole drilling machine 3. Therefore, the present invention can be applied very easily to existing taphole drilling machines.

As shown in FIG. 2(a) and FIG. 2(b), in the method for opening a blast furnace taphole of the present invention, the tip nozzle of the oxygen lance 6 has a laval formed from a nozzle with a tapered or wide-spread nozzle shape. A type of ceramic pipe 11 connected thereto is used. For example, a thread a may be cut in the oxygen lance 6 and the ceramic pipe 11, and the two may be screwed together. Thus, the tip of the oxygen lance 6 is made of a ceramic pipe 11 having a Laval tip nozzle shape, and is made of a material that can withstand hot metal temperatures of 1500 to 1800° C. during hole-opening work by oxygen injection.

Ceramic is a material with excellent corrosion resistance, but is susceptible to thermal shock and mechanical shock (cranking is likely to occur during hole drilling, so silicon nitride (Si?I'J), which has high thermal shock resistance, is used.
4) and boron nitride (BN) with strong thermal shock resistance, i.e., 60-95 wt% silicon nitride, 5-5 wt% boron nitride.
It is preferable that the tip nozzle shape of the ceramic pipe 11 made of 40wt% is made into a rubber shape and used by connecting it to the oxygen lance 6. If such a ceramic pipe 11 of 1/IJ composition is used, the spelling injection The speed is higher than the speed of sound, and there is also a port that can supply the necessary amount of oxygen, so that the hole-drilling operation is completed quickly and no cracks occur during the hole-drilling operation.

Although the bending strength decreases due to the mixing of boron nitride, the ceramic pipe 11 with a laval nozzle shape exists at the tip of the oxygen lance 6. It can be used without any problem.

In order to take advantage of the superior heat resistance of the ceramic pipe 11 and compensate for its weakness of poor mechanical shock resistance, a cylindrical metal socket 12 is installed at the tip of the oxygen lance 6, as shown in FIG. A ceramic pipe 1 with a laval tip nozzle shape is connected via a socket 12.
If a metal outer vIA 13 is fitted around the outer periphery of the metal vIA 13 to create a double structure for protection, e-zushi can also be used with ordinary ceramic materials instead of using ceramics made of silicon nitride and boron nitride as described above. It is possible to use. Further, since the mechanical strength is improved by the metal outer cylinder 13, the length of the portion of the ceramic pipe 11 having a laval-shaped tip nozzle can be increased.

The socket 12 has screws a cut at both ends as shown in FIG. The cylinder 13 is connected by screwing. The connection means is not limited to this, but as shown in FIG.
3 and the W1 elemental lance 6 may be connected by welding, and any connecting means that prevents the connection from coming off and oxygen from leaking can be used as appropriate.

[Metal outer cylinder 13 and socket] 2 is made of alloy steel with excellent heat resistance and erosion resistance, such as alloy steel with 5% or more Cr, or alloy steel with 5% or more Cr and 5% or more Ni (for example, 5% or more alloy steel).
US304) is preferably used, and if necessary, the oxygen lance 6 can also be made of such alloy steel. In order to further improve the heat resistance of the metal outer cylinder 13, the socket 12, and the oxygen lance 6, their surfaces may be subjected to a force-rolled treatment or ceramic spraying.

Example A steel rod 9 buried in a tap hole 2 using the device shown in FIG.
Oxygen was injected from the hole puncher 3 at a speed of Matsuha 1.6 to melt the steel rod 9, and the hole punching work was completed in 1 to 2 minutes. The drilling machine 3 used was one in which a ceramic pipe and an oxygen lance were connected as shown in FIG. 2(a).

The ceramic pipe is made of a mixture of 75 wt% silicon nitride and 25 wt% boron nitride, and the tip nozzle shape is a laval shape consisting of a wide-spread nozzle, and its inner diameter is 10 Wlφ on the inlet side. Neck part 7.
5 mmφ, 9.0 Mφ on the outlet side, and the length between the outlet side and the wedge was 8.5 mm, and the length between the wedge and the end on the inlet side was 5.0 mm.

For comparison, the same procedure as in the example was carried out except that a cylindrical one with an inner diameter of 10 m+ was used, and the time between the tap hole openings FR was about 5 minutes.

The Examples and Comparative Examples of the present invention have been shown above, and the results show that the Examples are about 1.・'5
~21. - It is possible to open holes between 588 and 588, and the service life of the ceramic pipe can be extended without causing damage such as cracks.

<Effects of the Invention> As explained above, in the method of the present invention, J! ! In the method of opening a blast furnace taphole by contacting an oxygen lance with a metal rod installed and injecting oxygen to melt the metal rod, a ceramic with a laval-shaped tip nozzle at the tip of the oxygen lance is used. The feature is that the pipes are connected and +11 element is injected into the metal rod through the ceramic pipe at the mouth to melt the metal rod and open a tap hole.

Therefore, according to the method of the present invention, a tip nozzle shape with excellent heat resistance injects the required amount of oxygen from a rubber/L-shaped ceramic pipe at a speed higher than the speed of sound, and is buried in the taphole plugging material in advance. Since the metal rod is melted, there is very little melting loss, and stable oxygen hole opening work can be performed in a short amount of time. Because of the hole, it can be easily used in existing taphole drilling machines, and the oxygen drilling work can be easily mechanized and automated, resulting in labor savings.

Further, when reinforcing the ceramic pipe as a double structure in which a metal pipe is fitted around the outer periphery of the ceramic pipe, the ceramic pipe can be made longer, so that the life of the oxygen lance can be further extended.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the implementation status of the tap hole drilling work according to the present invention, and FIG. 2 (a) and (b) show the structure of the oxygen lance used when implementing the present invention, +8) is a cross-sectional view, (b) is an enlarged cross-sectional view of the circled part in (a),
FIGS. 3 and 4 are cross-sectional views showing different embodiments of the II4 construction of the M-thickness used in the present invention. Code 1...Blast furnace shell 2...Tackle port 3...Drilling machine 4...Drilling machine support ¥1 5... ...Drifter 6...
Oxygen lance 7... Oxygen lance branch pipe 8... Valve 9... Steel rod 10
...Mud 11 ... Ceramic pipe 12 ... Socket 13 ... Metal outer cylinder Fig. 2 Mt.

Claims (1)

[Claims] 1) A blast furnace taphole is opened by abutting an oxygen lance against a metal rod that has been buried in a taphole plugging material in advance and injecting oxygen to melt the metal rod. In the method, a ceramic pipe having a tip nozzle shape of Laval is connected to the tip of the oxygen lance, and oxygen is injected to the metal rod through the ceramic pipe to melt the metal rod and open the tap hole. A method for opening a taphole in a blast furnace, which is characterized by drilling a hole. 2) The ceramic pipe contains 60 to 95 wt% silicon nitride.
, having a composition of 5 to 40 wt% boron nitride.
The taphole opening method of the blast furnace described. 3) The method for opening a tap hole in a blast furnace according to claim 1, wherein the ceramic pipe is protected by fitting a metal outer cylinder around its outer periphery.