JPH0853703A - Blast furnace tap hole forming method - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for forming a blast furnace tap hole capable of continuous tapping for a long time. [Composition] At the end of tapping, the mud is expanded with tapping, the mud is closed, the tap is closed, and the mud is heated and fired by furnace heat. Drill holes in a cylindrical shape that is larger than the hole diameter at the end of tapping, and keep the depth of the hole in a state where a mud with a thickness necessary to prevent the ejection of hot metal is left, and fluidity is maintained in the cylindrical openings. Inject a suitable amount of refractory, match the outer diameter of the solidified and molded in advance with the opening, and set the inner diameter to the hole diameter at the start of tapping, and insert the tubular refractory with the tip closed, A method for forming a taphole in a blast furnace, in which a gap between the inside of the hole and the outside of the refractory tubular body is filled so that the fluid refractory material overflows and is solidified by furnace heat to form a taphole. [Effect] Effectively utilizing the high corrosion resistance of the refractory tubular body,
Extend the continuous tapping time. There is no need to increase the filling power of the mad gun. The tap hole can be easily opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a tap hole of a blast furnace.

[0002]

2. Description of the Related Art A general method for forming and opening a tap hole in a conventional blast furnace is to fill the tap hole with mud at the end of tapping and close the tap hole. It was a general method to form a taphole by heating and firing with heat, and when tapping from the taphole was requested, tapping was performed by drilling the filling mud from the outside of the furnace. . As a new technique of the taphole structure, there is a technique described in JP-A-58-1007. This technique involves filling the blast furnace taphole with mud material, and then filling the mud material with a ceramic pile that has a function suitable for tapping conditions before solidification by firing or during partial firing. It is characterized in that it is punched in and penetrated, the hole of the pile is filled with a mud material and closed, and the diameter and thickness of the pile and the material are appropriately selected to control the tapping time and the tapping amount, Further, it is possible to enable long-term use only by driving the pile.

[0003]

In order to reduce the tapping work amount of the blast furnace and to reduce the tapping cost, efforts have been made to reduce the tapping frequency to the limit by continuous tapping for a long time. At the tapping end time at the taphole using the conventional forming and tapping method, the mud material on the hole wall of the taphole is eroded by the tapping and slag, and the hole diameter expands. It is determined by the fact that the tapping speed increases, the amount of molten hot metal stored in the furnace decreases, and the gas in the furnace begins to blow out from the tapping port. The current standard performance of large blast furnaces is 10 times / day of tapping and 2-3 hours / hour of continuous tapping, but it is common to reduce this to about 3 times / day of tapping. Is targeted at. The present inventors believe that it is possible to achieve the above-mentioned target long-term continuous tapping by improving the corrosion resistance of the mud material and reducing the enlargement of the hole diameter. We confirmed the existence of double-high corrosion resistant mud and applied this high corrosion resistant mud to the tap hole using the conventional forming and opening method, and grasped the process of extending the tapping time. As a result, the continuous tapping time can be extended only about 1.5 times even if a high corrosion resistant mud is used, and there is a large variation in the individual tapping time, making it difficult to achieve the above target for long-term continuous tapping Met.

Japanese Patent Laid-Open No. 58-58, which is a new technique of a taphole structure.
The technique described in Japanese Unexamined Patent Publication No. 1007 has the following problems in its implementation. The technique described in this publication is a technique in which a blast furnace taphole is filled with mud material, and then a ceramic pile is driven into the mud material before the filled mud material is sintered and solidified or during partial sintering. Therefore, it is assumed that the outer diameter of the ceramic pile is smaller than the outer diameter of the filled mud material (= the inner diameter of the tap hole at the time when the previous tap was finished). In this case, since the thickness of the ceramic pile at the start of tapping becomes thin, the ceramic pile can be used even if it is tapped once, unless a fine ceramic material with outstanding corrosion resistance to pig iron slag is used. There is a possibility that it will not be possible, and such materials are expensive even if they exist at present, and it seems that the cost will increase.

If the outer diameter of the ceramic pile to be driven is larger than the outer diameter of the filled mud material, the outer periphery of the ceramic pile is driven into the completely sintered and solidified mud material. In this case, In order to drive a ceramic pile, a dedicated driving machine that exerts a huge driving force is required, and the huge driving force applied during driving does not break either the ceramic pile or the sinter-hardened taphole mud material. I don't think so. The present invention has been made in view of the above problems, and an object thereof is to provide a method for forming a blast furnace tap hole in which continuous tapping time is extended.

[0006]

In order to achieve the above-mentioned object, a method for forming a taphole of a blast furnace according to the present invention is to fill a mud at the taphole expanded with tapping with mud at the end of tapping of the blast furnace. After closing the tap hole and heating and firing the mud by furnace heat, the mud is drilled with a bit for drilling into a columnar shape larger than the hole diameter at the end of tapping, and the depth of the hot metal is increased. Keep the mud of the thickness necessary to prevent the spouting of the, the flowable refractory is injected in an appropriate amount into the cylindrical opening, the outer diameter pre-molded and solidified to match the opening, A refractory tubular body having a hole diameter at the time of starting tapping and having a closed tip portion is inserted, and the fluid refractory material is placed in a gap between the inside of the opening and the outside of the refractory tubular body. It is characterized in that it is filled so as to overflow, and is solidified by furnace heat to form a tap hole.

[0007]

The inventor of the present invention observed the tapping condition at the tapping port using the conventional forming and opening method, and found that the cause of shortening the tapping time was as follows. The tap hole opening diameter at the start of tapping is about 50 mm, and the hole size at the end of tapping is generally eroded by the tapping and slag of the mud and expanded to about 100 mm. The tapping time is 2
~ 3 hours / time. Therefore, when the tap hole is closed at the end of tapping, the outer diameter of the newly filled mud is about 100 mm, which is the hole diameter at the end of tapping, and when the tap hole is opened at the next tapping with a diameter of about 50 mm, it is newly filled. It is assumed that the mud has a tubular shape, and the thickness of the mud tube is about 25 mm.

On the other hand, when the taphole is closed at the end of tapping, the state of the inside of the taphole is as follows: the mud is pushed into the inside of the furnace while the mud is pushed into the borehole. On the contact surface of the newly filled mud, pig iron and slag remain fixed, and the inner surface of the opening is a solidified surface after the mud is melted by tapping and slag. Even if the contact surface of the newly filled mud is heated and baked, the mutual adhesion becomes weak.

From the above situation, it is considered that the conventional tap hole is a thin cylindrical mud having a strength of holding and holding from the outer surface weak at the start of tapping and a tube thickness of about 25 mm.
This fragile tubular mud is eroded by tapping and slag during tapping and becomes thinner, and it self-destructs and peels off due to the hot metal pressure received by tapping at an early stage and the thermal stress generated in the tubular body, resulting in an open hole diameter. It is probable that the end of tapping was accelerated due to the rapid expansion of No.

The operation of the taphole forming method of the present invention is as follows. At the end of tapping, the mud is filled with a mud gun and the tap is closed. After the mud is heated and baked by the heat in the furnace, the mud is drilled from the outside of the furnace so that the inner diameter of the opening is slightly larger than the outer diameter of the cylindrical refractory body to be inserted later. Means that the inner surface of the opening is a surface that has solidified after melting of the above-mentioned pig, slag sticking and mud, as it means that the refractory cylindrical body inserted last time is scraped off to a place slightly larger than its outer diameter. Instead, it does not prevent strong sintering and fixation through a refractory tubular body to be inserted later and a flowable refractory, since it results in a beautiful fired refractory surface. Since the hot metal in the furnace does not flow out in this step, since the undrilled portion of the mud having a thickness necessary to prevent the hot metal from being blown out is left inside the furnace, the refractory cylinder Easy insertion work.

The refractory tubular body to be inserted into the opening is made by molding and solidifying the refractory material having the high corrosion resistance mud or the equivalent corrosion resistance, and has a hole diameter suitable for the next tapping. The tubular body has an outer diameter that maintains a structural strength that does not cause self-destruction by the tapping even after the tapping hole diameter has been eroded and expanded by the end of one tapping. Do not open the tip and keep it blind. The length of the tubular body should be slightly shorter than the length of the above-mentioned opening. An appropriate amount of fluid refractory material is injected into the opening, and the refractory tubular body is inserted into the opening from the outside of the furnace. The opening diameter is slightly larger than the outer diameter of the tubular body. Since it can be inserted by applying a small insertion force to the tubular body, the tubular body can be inserted by the feed force of the conventional tap hole opening machine, and it is not necessary to install a new tubular body insertion device.

During the insertion of the tubular body, the fluid refractory material previously injected is pushed by the blind portion at the tip of the tubular body to fill the space between the tip of the tubular body and the tip of the opening, and the outer diameter of the tubular body. And also fills the gap between the inner diameter of the opening. Insert the tubular body until the outer end surface of the tubular body matches the outer surface of the tap hole, and after waiting for a certain time, the fluid refractory filled in the outer side of the tubular body is heated and fired by the heat in the furnace. Since the adhesive strength is developed, the tubular body is bonded and fixed in a form integrated with the taphole, so that the tubular body self-destructs due to the hot metal pressure and thermal stress received by the taphole
It is possible to reduce the limit of the thickness of the tubular body that is peeled off and discharged, and the diameter of the tap hole is rapidly expanded. When tapping from the taphole is required, the taphole opening method is as follows: the conventional taphole opening machine, rod, and bit for opening the blind portion at the tip of the tubular body and the taphole. The undrilled part of the mud left inside the furnace is drilled. Since the outer diameter of the hole bit used at this time is a little smaller than the inner diameter of the hole of the cylindrical body, it is not necessary to scrape the inner surface of the hole of the cylindrical body to break the cylindrical body. Since the length corresponding to the length previously drilled in the tubular body can be excluded, the length is extremely short, so that the drilling work can be easily performed.

Since the erosion expansion limit diameter of the tap hole opening that can be allowed at the end of tapping is determined by the operating conditions of the blast furnace, the outer diameter of the highly corrosive refractory tubular body is taken out once the tap opening diameter is one. Since the thickness of the refractory tubular body is set to a level that maintains the structural strength that does not cause self-destruction by tapping even after the erosion is expanded by the end of the pig iron, the high corrosion resistance of the refractory tubular body is finished. It is possible to effectively use up to, the continuous tapping time can be extended, and the target tapping frequency can be reduced to about 3 times / day. Since the highly corrosive refractory tubular body has an open hole diameter that is eroded and expanded by one tapping and the tapping end time is determined, it cannot be used for the next tapping. The forming method is repeated for each tapping.

[0014]

The present invention will be described in detail below with reference to an embodiment. FIG. 1 is a cross-sectional view showing a state before tapping of a taphole using the forming method of the present invention. FIG. 2 is a sectional view showing a state immediately before the cylindrical refractory material of the present invention is inserted. FIG. 3 is a sectional view showing a state of a conventional taphole before tapping. At the end of tapping, tap tap 1
Fill the mud 2 with a mud gun and close the tap hole. The mud used at this time is the normal mud normally used. After the mud 2 is heated and fired by the heat in the furnace, the mud 2 is drilled from the outside of the furnace and the inner diameter of the opening is inserted later to be slightly larger than the outer diameter of the highly corrosion-resistant refractory tubular body 3. . The hole 4 including the previously inserted refractory tubular body 3 is cut to a position slightly larger than the outer diameter thereof, but the conventional hole tapping machine is used as the hole drilling machine. The mud 2 having a thickness of about 500 mm necessary to stop the hot metal inside the furnace 2
In this step, the hot metal 5 in the furnace does not flow out, because the undrilled portion is left.

The high-corrosion-resistant refractory tubular body 3 uses a mud or refractory material having a corrosion resistance to hot metal and slag that is 5 times or more that of the ordinary mud, and has a hole diameter suitable for tapping. It is a cylindrical body with a hole of 50 mm, and its outer diameter maintains a wall thickness that maintains the structural strength so that it does not self-destruct due to tapping even after the tapping hole diameter has been eroded and expanded by the end of one tapping. The outer diameter is about 120 mm, the tip of the tubular body is blind, and the length of the tubular body is slightly shorter than the length of the opening 4 described above. The refractory tubular body 3 molded into the above shape is preliminarily heated and fired in a firing furnace so as to have a uniform corrosion resistance.

An appropriate amount of fluid refractory 6 is injected into the drilled hole 4. Non-aqueous mortar is used as the flowable refractory, and it is injected into the opening with a pressure-feeding hose. Under this condition, the refractory tubular body 3 is inserted into the opening from the outside of the furnace.
Since the diameter of the opening is slightly larger than the outer diameter of the cylindrical body, the cylindrical body can be inserted by applying a small pushing force to the outer end of the cylindrical body. Therefore, the rod is attached to the tap hole opening machine. The tip of this rod is inserted into the opening of the tubular body to hold the tubular body, and the tubular body is inserted by the feed force of the tap hole opening machine.

During the insertion of the tubular body, the mortar 6, which is the fluid refractory previously injected, is pushed by the blind portion at the tip of the tubular body to fill between the tip of the tubular body and the tip of the opening 4, and The excess mortar overflows outside the furnace, filling the gap between the outer diameter of the tubular body and the inner diameter of the opening. Insert the end surface of the cylindrical body outside the furnace until it matches the outer surface of the tap hole, and wait for a certain period of time. Then, the mortar 6 filled in the outer periphery of the cylindrical body is heated and baked by the heat in the furnace to improve the adhesive strength. In order to develop, the tubular body is adhered and fixed integrally with the tap hole to form the tap hole. When tapping from the taphole is required, the taphole opening method is as follows: a conventional taphole punching machine, a rod, and a bit for opening a blind portion at the tip of the refractory tubular body 3. Before inserting the tubular body, the undrilled portion of the mud left inside the furnace is drilled. The opening bit used at this time has an outer diameter slightly smaller than the inner diameter of the opening of the cylindrical body. After the tapping is finished, the process returns to the writing in the present embodiment, the next tapping hole is formed, and this is sequentially repeated.

[0018]

【The invention's effect】

1. Since the outer diameter of the highly corrosion resistant refractory tubular body is set to a size that maintains a structural strength that does not cause self-destruction by the tapping even after the tapping hole diameter has been eroded and expanded by the end of tapping, The high corrosion resistance of the refractory can be effectively used until the end of tapping, the continuous tapping time can be extended, and the target tapping frequency can be reduced to about 3 times / day. 2. Before the insertion of the tap hole before inserting the refractory tubular body, the inner surface of the opening has a larger diameter than the outer diameter of the tubular body, so there is no adhesion of pigs and slag, and a clean refractory surface is obtained. , Since it is strongly baked and fixed through the refractory tubular body and the fluid refractory to be inserted later, the tubular body is self-destructed and peeled off due to the hot metal pressure received by the tapping and the thermal stress generated in the tubular body, It is possible to reduce the limit of the thickness of the tubular body that causes a rapid expansion of the tap hole opening diameter. 3. Highly corrosion resistant mud or highly corrosion resistant refractory material is molded into a tubular shape in advance and heated and fired in a firing furnace in advance, so it is possible to keep the refractory tubular body with uniform corrosion resistance. it can.

4. When filling the taphole with a high corrosion resistant mud with a mud gun, the high corrosion resistant mud is much harder than the normal mud, so the mud gun filling pushing force becomes very large, and it is necessary to increase the capacity of the mud gun. In the invention, since the normal mud is filled with the mud gun, the highly anticorrosive refractory can be used as the tubular body without modifying or renewing the equipment for increasing the filling power of the mud gun. 5. Before the insertion of the refractory tubular body, the taphole has a diameter larger than the outer diameter of the tubular body to be inserted, so the tubular body can be easily inserted and it is necessary to install a dedicated tubular body driving machine. There is no. 6. The tap hole opening is a conventional tap hole opening machine, rod and bit for opening, and the blind part of the refractory tubular body and the uncut hole of the mud left inside the furnace before inserting the tubular body Since only the part is drilled, it is easy to open the hole when tapping.

[Brief description of drawings]

FIG. 1 is a sectional view showing a state of a taphole before tapping using a forming method of the present invention.

FIG. 2 is a cross-sectional view showing a state immediately before the cylindrical refractory material of the present invention is inserted.

FIG. 3 is a cross-sectional view showing a state of a conventional taphole before tapping.

[Explanation of symbols]

 1 tap hole 2 mud 3 highly corrosion-resistant refractory tube 4 open hole 5 hot metal in the furnace 6 fluid refractory (mortar) 7 previous mud

Claims (1)

[Claims] 1. At the end of tapping of the blast furnace, a mud is filled in the tap hole expanded with tapping, the taphole is closed, the mud is heated and baked by furnace heat, and then the mud is opened. Drill a hole with a bit for holes into a column shape larger than the hole diameter at the end of tapping,
The opening depth was kept in a state in which a mud having a thickness necessary to prevent the ejection of hot metal was left, and an appropriate amount of fluid refractory material was injected into the cylindrical opening, and the outer diameter preformed and solidified was the opening. In accordance with the, the inner diameter is set to the hole diameter at the start of tapping, and a refractory tubular body with a closed tip is inserted, and the gap is formed between the inside of the opening and the outside of the refractory tubular body. A method for forming a taphole in a blast furnace, which comprises filling a flowable refractory so that it overflows and solidifying it by furnace heat to form a taphole.