JPH10317027A - Device for controlling molten iron and slag tapping speed in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect an electromagnetic energy supplying body arranged around a guide tube arranged at the furnace outside of an iron tapping hole from high temp. SOLUTION: The guide tube 10 arranged at the furnace outside of the iron tapping hole 2 is formed into a double-structure in the wall thickness direction composed of an outside refractory layer 16 and an inside refractory layer 17 by which thermal insulation property is improved, and the electromagnetic energy supplying body 11 arranged around the guide tube 10 is protected from the high temp. Further, only the inside refractory layer 17 worn with molten slag 9, is changed and the outside refractory layer 16 is reused to reduce the refractory cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive pipe which is connected to the outside of a taphole in a furnace, applies electromagnetic energy from an electromagnetic energy supplier disposed around the conductive pipe, and controls the inside of the conductive pipe. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapping speed control device for a blast furnace, in which flowing hot metal is collected at a central portion by magnetic pressure due to electromagnetic repulsion, and the slag is displaced around the central portion.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 10, iron ore and coke are charged alternately into a furnace from the furnace top of a blast furnace 1 and hot air is blown from a tuyere 3 at a furnace bottom. The iron ore and coke charged in the furnace descend while reducing and pulverizing the iron ore while maintaining a layered structure of the iron ore and the coke in the shaft portion. Then, the charge descends in a complicated manner typified by a slash-like flow into the upper part of the raceway 4 formed in front of the tuyere 3 and a stagnation in the core. An inverted V-shaped, W-shaped, etc. cohesive zone is formed by the balance of the respective heat flow rates of the descending charge and the ascending gas, and the molten iron 5 and the slag 6 are formed on the furnace bottom via the drip zone 7. Accumulates. Note that a mud material 18 filled with a mud gun is present inside the furnace of the tap hole 2.

[0003] Hot metal 5 and slag 6 accumulated at the bottom of the blast furnace 1
Is discharged to the tapping gutter 8 through the taphole 2. The mud refractory 13 that forms the inner surface of the tap hole 2 when tapping starts,
The diameter of the hole gradually increases due to the wear caused by the hot metal 5. Therefore, the flow rate of hot metal 5 or slag 6 discharged from taphole 2 is
It increases as the hole diameter increases. As a result, at the beginning of tapping, since the tap hole 2 has a small diameter, the tapping slag speed is smaller than the slag making speed in the furnace, so even if there is a period during which the molten slag level in the furnace temporarily increases, Eventually, the tapping slag speed becomes higher than the slag making speed due to the wear of the taphole 2, and the molten slag level in the furnace decreases. Therefore, the furnace gas existing on the slag 6 is finally blown out from the tap hole 2. Before this happens, a taphole 2 is usually used with a mud gun.
Pressing a mud (amorphous refractory) into the furnace interrupts tapping slag.

A case in which a plurality of tap holes 2 are provided in a blast furnace and lap tapping is performed from, for example, two tap holes will be described. In the state where lap tapping is performed, FIG.
As shown in the figure, the tapping slag from one tap hole 2 provided in the blast furnace 1 is terminated and closed with a mud, and the remaining tap hole 2 is left.
When the tapping slag is continued only from the furnace, since the speed of the tapping slag in the furnace is higher than the speed of the tapping slag, the amount of the hot metal 5 and the slag 6 that accumulate at the bottom of the furnace increases, and the level of the hot metal slag increases. The hot metal 5 existing below the slag 6 is tapped. At the stage where the molten iron slag level has risen to the set level due to the rise in the molten metal level in the furnace, one of the closed tap holes 2 is opened again using the opening machine as shown in FIG. Tapping is started from the taphole 2 and lap tapping with the other taphole 2 is performed. At the beginning of the opening, the hole diameter of the taphole 2 is small, so that the speed of the ironmaking slag in the furnace is higher than the speed of the tapping slag, and the level of the molten iron slag in the furnace further increases. Thereafter, as shown in FIG. 11 (C), when the lower end of the slag 6 reaches the tap hole 2 due to a decrease in the level of the hot metal 5, tapping is terminated and slag is started.

[0005] The inner wall mud of the taphole 2 wears out with the tapping time, the hole diameter of the taphole 2 gradually increases, and the tapping slag speed gradually increases. As a result, when the speed of the ironmaking slag in the furnace becomes smaller than the speed of the tapping slag, as shown in FIG. Mud refractory 13 for taphole 2
Is further worn away with the tapping time, and the diameter of the taphole 2 is increased. For this reason, as shown in FIG.
Then, as shown in FIG. 11 (F), the boundary surface between the slag 6 and the gas in the furnace reaches the level of the tap hole 2, and the gas in the furnace is ejected from the tap hole 2. Begin to. In this state, continuation of tapping slag becomes impossible, so that the taphole 2 is filled with mud with a mud gun and tapping is terminated. What determines the time of the tapping slag is mainly the durability of the mud refractory 13 filled in the taphole 2. Since the wear rate of the filled mud refractory 13 increases in proportion to the flow rate of the molten slag, the amount of slag increases in proportion to the slag time.

[0006] In such tapping slag, the continuous tapping time from the same taphole 2 is about 3 to 4 hours, and severe opening and closing operations of the taphole 2 must be performed frequently. Therefore, it is necessary to secure a large number of workers, which not only hinders labor saving but also results in the use of a large amount of auxiliary materials for opening and closing operations. These issues are:
The original cause is the increase in the hole diameter due to the low durability of the taphole refractory. However, if the durability is improved too much, there is a problem that the opening of the taphole 2 becomes difficult. Is late.

[0007] Prolonging the time of one tapping of the blast furnace 1 leads to a reduction in the number of tappings, and in addition to a reduction in the number of working staff, a reduction in the amount of metal rods and mud refractories, and the addition of hot metal. There is a strong demand for stabilizing the quality and reducing the amount of tapping Si. To cope with such a demand,
In Japanese Patent Application Laid-Open No. 7-188717, a conducting tube 10 is connected to the outside of the taphole 2 as shown in FIG. Electromagnetic energy is applied to the tapping slag 9 flowing through the slag to give a magnetic pressure due to electromagnetic repulsion, and the cross section of the hot metal 5 is adjusted by the contraction flow that compresses the flow diameter of the hot metal 5 and is discharged from the taphole 2. An apparatus for controlling the speed of molten iron slag is disclosed.

A water passage 15 is provided inside the conduit 10 as shown in FIG.
Cool the inner wall of 10 and adjust the amount of heat removed by this cooling,
The flow rate of tapping slag 9 is controlled by changing the thickness of the slag solidified layer 21 formed inside the conduit 10.

[0009]

However, the one disclosed in Japanese Patent Application Laid-Open No. 7-188717 has the following problems. (1) A thick slag solidified layer with sufficient strength to allow the molten iron slag having a temperature much higher than the melting point of the slag solidified layer to flow at a high speed in the slag solidified layer formed inside the conduit. Is difficult to form, and a thin slag solidified layer having poor strength is not obtained, and sufficient heat insulation cannot be obtained.

(2) When the heat supply from the molten iron slag is stopped after the completion of tapping, the inner surface of the slag solidified layer formed in the conduit has cracks due to shrinkage due to a temperature drop. (3) When the inside of the conduit becomes as described in (1) or (2) above,
Since the hot metal is mainly discharged from the tap hole at the beginning of tapping, the thin slag solidified layer with low strength is broken, and the broken slag solidified layer is washed away. A thin solidified layer is formed. In such a case, the heat loss of the hot metal through the thin solidified layer of the hot metal increases the heat loss of the hot metal, and the heat transfer to the cooling surface is liable to be hindered, so that the formation of a more stable slag solidified layer becomes more difficult.

(4) The thin solidified layer of hot metal formed in the conduit as described in (3) acts as a shield material for magnetic energy applied from the electromagnetic energy supply,
Since the supply of magnetic energy to the hot metal flow is hindered, the flow rate control of the hot metal slag becomes insufficient. (5) When hot molten iron slag directly contacts the water cooling wall provided in the conduit, there is a danger of steam explosion due to melting and cracking of the water cooling wall, impeding safe operation.

In order to solve the problems of the prior art, the present invention is to improve a flow path in which magnetic energy applied from an electromagnetic energy supplier contacts a molten iron slag flowing in the flow pipe. It is an object of the present invention to provide a blast furnace tapping speed control device capable of efficiently adjusting the flow rate of molten iron slag without being affected by a slag solidification layer formed inside the blast furnace.

[0013]

According to a first aspect of the present invention, there is provided a conductive pipe connected to the outside of a taphole outside a furnace, and disposed around the conductive pipe. Apparatus for applying electromagnetic energy from an electromagnetic energy supply, collecting hot metal flowing through the conduit at a central portion by magnetic pressure due to electromagnetic repulsion, and displacing slag in a peripheral portion thereof to control a tapping speed control device of a blast furnace. The blast furnace tapping speed control device for a blast furnace according to any one of claims 1 to 3, wherein the conduit is constituted by a plurality of refractory layers stacked in a thickness direction.

According to a second aspect of the present invention, there is provided a conduction pipe connected to the outside of the taphole at the furnace, and electromagnetic energy is applied from an electromagnetic energy supply member disposed around the conduction pipe to provide the conduction. In a tapping speed control device for a blast furnace in which molten metal flowing in a pipe is collected at a central portion by magnetic pressure due to electromagnetic repulsion and the molten metal is deflected to a peripheral portion, the conductive pipe is disposed outside in a thickness direction. A tapping speed control device for a blast furnace, comprising: an outer water cooling wall provided; and a plurality of inner refractory layers disposed inside the outer water cooling wall.

According to a third aspect of the present invention, at least the inner refractory layer that is in contact with at least the tapping slag stream forming the conduit is provided.
The tapping speed control apparatus for a blast furnace according to claim 1 or 2, wherein the apparatus is divided into a plurality of pieces in a circumferential direction. According to the present invention as set forth in claim 4, a notch serving as a starting point of refractory cracking due to thermal stress is provided at intervals on an outer peripheral surface of an inner refractory layer that comes into contact with at least a tapping slag stream constituting the conduit. The tapping speed control apparatus for a blast furnace according to claim 1 or 2, characterized in that:

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, as shown in FIG. 1, a conductive tube 10 disposed outside the furnace of the taphole 2 is constituted by an outer refractory layer 16 and an inner refractory layer 17 which are laminated in the thickness direction.
It is to have a heavy structure.

Hot metal 5 and slag 6 collected at the bottom of the blast furnace 1 are tapped through the tap hole 2, and an electromagnetic energy supply 11 disposed on the outer periphery of the conductive pipe 10 allows the hot metal 5 and the molten slag 6 to enter the conductive pipe 10. Electromagnetic energy is applied to the hot metal 5 flowing through. The hot metal 5 receives the magnetic pressure due to the electromagnetic repulsion, and as shown in FIG.
It gathers at the center of the flow path formed in the inner refractory layer 17 constituting 10 and becomes a contracted flow. As a result, the slag 6 is pushed to the inner refractory layer 17 side and flows in a state where the slag 6 is separated into the central hot metal 5 and the outer slag 6. At this time, hot metal 5
The cross-sectional area of the flow path is adjusted by the contraction of the molten iron, and the speed of the molten iron slag discharged from the taphole 2 is controlled. At the same time, the change in the flow of the hot metal 5 also affects the state in which the slag 6 flows out of the furnace, changes the interface level between the hot metal 5 and the slag 6 in the furnace, the hot metal 5 in the tap hole 2, and the slag 6. Causes a change in the cross-sectional area ratio or a change in the differential pressure before and after the taphole 2, and the flow rate of the slag 6 also changes.

In controlling the flow rate of tapping slag utilizing these phenomena, in the present invention, the conduit tube 10 is made up of the outer refractory layer 16 and the inner refractory layer 17 which are laminated in the thickness direction, thereby achieving a stable operation. A heat insulation layer is maintained, thereby ensuring thermal protection of the electromagnetic energy supply 11 and the like disposed around the conduit 10. Double refractories or 3 if necessary
When the number of layers is equal to or greater than the weight, the temperature difference between the inner and outer surfaces of each refractory layer can be reduced, and the thermal stress acting on the refractory is suppressed. In addition, when exchanging refractory which is extremely worn due to contact with the molten iron slag, if only a plurality of layers are used, only the inner refractory layer 17 which is worn due to contact with the molten iron slag needs to be exchanged, so that cost reduction can be achieved.

It is important to reduce the thermal stress of the refractory layer, and a part of the refractory layer is formed of a powdery refractory (unshaped material) so as to be small enough to prevent cracking. Although it is also possible, it is difficult to apply this to a portion in contact with molten iron slag from the viewpoint of durability. Therefore, in the present invention, as shown in FIG.
It is preferable to adopt a structure in which 17 is divided in the circumferential direction (in the drawing, an arc-shaped refractory layer divided into four parts is joined at the joining part 19).

When the inner refractory layer 17 is not divided in the circumferential direction as shown in FIG. 2, the inner refractory layer 17 has a high temperature on the inner surface side and a large expansion, so that a tensile stress is generated on the outer peripheral side. As a result, the risk of the outer peripheral side cracking due to tensile stress increases. On the other hand, when the inner refractory layer 17 is divided in the circumferential direction as shown in FIG. 3, the arc-shaped refractory layer divided into four parts is deformed so as to be warped outward due to tensile stress, and each joint portion Clearance occurs on the outer peripheral side, but the inner peripheral side is in close contact, so that the molten iron slag hardly leaks from the clearance. In this case, if each joint 19 is filled with a jointing agent, it is possible to more suitably prevent the molten iron slag from leaking.

FIG. 4 shows the inner refractory layer in contact with the molten iron slag.
17 shows a structure in which notches 20 are arranged on the outer peripheral side of 17 (four notches are arranged at equal intervals on the outer periphery in the drawing). In this case, when thermal expansion distortion occurs due to a temperature difference between the inner and outer peripheries of the inner refractory layer 17, the thermal expansion distortion concentrates on the notch 20, and the inner refractory layer 17 is moved from the notch 20 as a starting point in the circumferential direction. The thermal expansion strain is released because of cracking. The crack originating from the notch 20 provided in the inner refractory layer 17 forms a gap on the outer peripheral side, but since the inner peripheral side is in close contact, the molten iron slag hardly leaks from the gap, and is shown in FIG. The same effect as in the case of the divided structure can be exhibited.

Next, another embodiment of the present invention will be described. In the present invention, as a heat resistance measure of the conduit 10 disposed outside the furnace of the taphole 2, the conduit 10 is constituted by an outer water cooling wall 12 in the thickness direction and an inner refractory layer 17 as shown in FIG. 2
Double structure. A water passage 15 is provided in the outer water-cooling wall 12, and an inner refractory layer 17 is provided in advance so as to be laminated inside the outer water-cooling wall 12, thereby forming a stable heat-insulating protective wall. Although FIG. 5 shows a case where only one inner refractory layer 17 is provided inside the outer water cooling wall 12, two or more layers can be provided as necessary.

In this case, the inner refractory layer 17 is
No self-fringing by a slag solidified layer formed inside by water cooling of 12 is expected, and it is intended to achieve stable heat insulation by interposing as a substitute for the slag solidified layer. In addition, the inner refractory layer 17 is inevitably worn due to prolonged contact with hot metal slag and its exchange is inevitable.
The molten iron slag is prevented from coming into direct contact with the
The danger of steam explosion caused by erosion can be greatly reduced.

The outer water-cooling wall 12 may be formed as an annular one-piece. However, in order to transmit the electromagnetic force to the flow of the hot metal 5 efficiently through the outer water-cooling wall 12 from the electromagnetic energy supply 11. Preferably, the outer water cooling wall 12 is divided into two sections, and each is insulated by an insulator 14. In this case, if the inner refractory layer 17 does not exist inside the outer water cooling wall 12, there is a risk that the solidified layer of the hot metal 5 adheres to the outer water cooling wall 12 and insulation cannot be maintained. Thereby, the insulation of the outer water cooling wall 12 divided can be reliably maintained.

In the present invention, as shown in FIG. 6, the inner refractory layer 17 in contact with the molten iron slag has a structure divided in the circumferential direction (in the drawing, the arc-shaped refractory layer divided into four parts is joined at the joint 19). Preferably, this is the same as described with reference to FIG. Further, as shown in FIG. 7, a structure in which notches 20 are arranged on the outer peripheral side of the inner refractory layer 17 in contact with the molten iron slag (in the drawing, four notches are arranged at equal intervals on the outer periphery) may be employed. What can be performed is the same as that described with reference to FIG.

[0026]

As described above, according to the present invention, a plurality of refractory layers laminated in the thickness direction or a plurality of inner refractory layers inside the outer water-cooling wall are formed by connecting a conducting tube disposed outside the furnace at the taphole. The layered structure ensures stable protection of electrical equipment, such as electromagnetic energy supply, placed around the conduit, and minimizes the replacement of refractory due to wear of the refractory layer. Can be stopped.

The formation of a solidified layer of hot metal on the inner surface of the outer water cooling wall can be prevented by the plurality of inner refractory layers, so that the shielding of the electromagnetic force applied from the electromagnetic energy supplier can be reduced. The inner refractory layer that comes into contact with the tapping waste stream is divided into a plurality of parts in the circumferential direction, or notches that serve as starting points for refractory cracking due to thermal stress are provided on the outer peripheral surface of the inner refractory layer at intervals. The thermal stress generated in the refractory due to the temperature difference between the inner and outer surfaces of the inner refractory layer can be easily released.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a tapping slag situation by a tapping slag speed control device for a blast furnace according to the present invention.

FIG. 2 is a cross-sectional view showing a case where the conduit tube of the present invention is formed of an outer refractory layer and an inner refractory layer.

FIG. 3 is a cross-sectional view showing a case where the conduit according to the present invention is formed of an outer refractory layer and an inner refractory layer, and the inner refractory layer is divided into a plurality in the circumferential direction.

FIG. 4 is a cross-sectional view showing a case where the conduit according to the present invention is formed of an outer refractory layer and an inner refractory layer, and notches are provided at intervals on the outer peripheral surface of the inner refractory layer.

FIG. 5 is a cross-sectional view showing a case where the conduit tube of the present invention is configured by an outer water cooling wall and an inner refractory layer.

FIG. 6 is a cross-sectional view showing a case where the conduit tube of the present invention is constituted by an outer water-cooling wall and an inner refractory layer, and the inner refractory layer is divided into a plurality in the circumferential direction.

FIG. 7 is a cross-sectional view showing a case where the conduit tube of the present invention is formed of an outer water-cooling wall and an inner refractory layer, and is provided with cutouts on an outer peripheral surface of the inner refractory layer.

FIG. 8 is an explanatory diagram showing a tapping slag situation by a conventional tapping speed control apparatus for a blast furnace.

FIG. 9 is a sectional view showing a conventional conduit.

FIG. 10 is an explanatory diagram showing a tapping state from a taphole of a conventional blast furnace.

FIG. 11 is an explanatory diagram illustrating a change in a molten metal level and a molten metal level in a furnace when a lap tapping operation is performed from a plurality of tap holes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Tap hole 3 Tuyere 4 Raceway 5 Hot metal 6 Slag 7 Drip zone 8 Tapping gutter 9 Tapping slag 10 Conducting tube 11 Electromagnetic energy supply body 12 Outside water cooling wall 13 Mud refractory 14 Insulator 15 Water passage 16 Outer refractory layer 17 Inner refractory layer 18 Mud material 19 Joint 20 Notch 21 Slag solidification layer

Claims (4)

[Claims] 1. A conductive tube connected to the outside of a taphole of a furnace, a conductive tube is disposed, and electromagnetic energy is applied from an electromagnetic energy supply member disposed around the conductive tube, and the hot metal flowing through the conductive tube is subjected to electromagnetic repulsion. In the tapping speed control device of the blast furnace in which the molten metal is collected at the center by the magnetic pressure according to the above and the slag is displaced to the peripheral portion, the conduit is constituted by a plurality of refractory layers laminated in the thickness direction. A tapping speed control device for a blast furnace, characterized in that: 2. A conductive pipe connected to the outside of the taphole at the furnace, electromagnetic energy is applied from an electromagnetic energy supplier disposed around the conductive pipe, and hot metal flowing in the conductive pipe is repelled by electromagnetic waves. In the tapping speed control device of the blast furnace, in which the molten metal is collected at the center by the magnetic pressure according to the above, and the slag is displaced to the periphery thereof, the outer pipe is provided with the outer pipe in the thickness direction of the conduit. And a plurality of inner refractory layers disposed inside the outer water cooling wall. 3. The blast furnace tapping speed control of a blast furnace according to claim 1, wherein at least the inner refractory layer that is in contact with at least the tapping tap stream constituting the conduction pipe is divided into a plurality in the circumferential direction. apparatus. 4. A notch serving as a starting point of refractory cracking due to thermal stress is provided at intervals on at least an outer peripheral surface of an inner refractory layer which is in contact with a tapping slag stream constituting the conduit. 3. The tapping speed control device for a blast furnace according to claim 1 or 2.