JP5606152B2 - How to remove ladles from ladle - Google Patents

Description

  The present invention relates to a metal removal method for a ladle that removes metal that has adhered to the ladle.

Conventionally, when a ladle is used over a plurality of charges (a plurality of heats), a lot of metal is attached to the ladle, and therefore, the metal in the ladle is periodically removed. As a method and an apparatus for removing the bare metal adhering to the ladle, there are those shown in Patent Document 1 and Patent Document 2.
In Patent Literature 1, in the pan discharge port deposit removal device, a forward / reverse device attached to the upper movable frame in a direction orthogonal to the traveling direction of the pan transporter, and a hydraulic breaker that moves forward / backward by the forward / backward device This hydraulic breaker has a rod with a plate with the same cross-sectional dimensions as the pan groove at the tip of the rod. A sharp bit at the tip is near the lower end of the plate, and the bottom surface of the rod and the bottom surface of the bit are in a straight line. It is disclosed that it is attached to become.

Moreover, although not limited to a ladle, there exists what is shown to patent document 2 and patent document 3 as a technique which makes it easy to take the metal | base metal adhering to a refractory.
In patent document 2, in the method of forcibly cooling the refractory and the deposit on the surface of the refractory, it is disclosed to cool the portion to be cooled by spraying dry ice. Further, in Patent Document 3, in order to continuously use the tundish by repeatedly injecting molten metal into the mold and tilting and draining, a tip of the tundish is previously placed outside the tundish in the passage of the draining port. Attach the drainage port mounting tool that protrudes, and attach and enlarge the deposits that have adhered and enlarged on the mounting tool by tilting the wastewater multiple times. It is disclosed to drop and remove.

JP 2002-80909 A JP 2001-108377 A Japanese Patent Application Laid-Open No. 10-328796

  In Patent Document 1 and Patent Document 3, an attempt is made to remove the bullion by mechanically hitting the bullion. However, in these techniques, the bullion is simply given by hitting the bullion. It is only disclosed that the metal is removed, and the temperature at the time of removing the metal is not considered at all. Patent Document 2 discloses a technique for facilitating the removal of a bullion by forcibly cooling a deposit such as a bullion, but it is disclosed that this technique can be easily removed by simply cooling the bullion. However, it is not disclosed at all how to set the temperature specifically.

In other words, Patent Documents 1 to 3 do not consider any specific guidelines on how to control the temperature when removing the bare metal. In addition to not being able to remove gold, there is a problem that the fixing rate of the sprayed material is deteriorated in the operation of spraying the irregular refractory performed after the removal of the metal.
Therefore, in the present invention, when removing the bullion attached to the ladle, the removal rate of the removed bullion can be improved, and the fixing rate of the spraying material performed after the bullion removal can also be improved. The object is to provide a method for removing bullion from a ladle.

In order to achieve the above object, the present invention has taken the following measures.
When the technical means of the present invention is to remove the metal attached to the refractory of the ladle for steel making, after discharging the molten metal in the ladle, the metal temperature to be removed is 800 ° C to 300 ° C. The point is that the bullion is removed by striking or hooking.

  According to the present invention, when removing the bullion attached to the ladle, the removal rate of the removed bullion can be improved, and the fixing rate of the spraying material performed after the bullion removal can also be improved. .

It is the figure which showed the whole ladle sectional drawing. It is the figure which showed the state which removes the tilting apparatus which tilts a ladle, and a metal. It is a figure which shows the shrinkage | contraction difference of pure iron and a refractory. It is the figure which showed the average linear expansion coefficient and shrinkage | contraction amount when changing carbon amount. It is a related figure of the metal removal rate with respect to the metal temperature when the ladle for hot metal is maintained, and the spraying material fixation rate. It is a related figure of the bullion removal rate with respect to the bullion temperature when the ladle for molten steel is prepared, and the spraying material fixation rate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In a steelmaking factory, a ladle is generally used when transporting or refining hot metal or molten steel. For example, the ladle is used to convey the molten iron discharged from the blast furnace, convey the molten iron discharged from the kneading car, or convey the molten steel discharged from the converter. It is also used when performing secondary refining or injecting molten steel into a continuous casting apparatus.

Thus, in a steelmaking factory, a ladle is used in various processes, and when transporting molten steel or hot metal, or when refining molten iron or molten steel, a metal bar adheres in the ladle. If a large amount of metal is attached to the ladle, the ladle will be transported to the ladle maintenance factory that maintains the ladle, for example, and the metal that has adhered to the ladle will be removed at the ladle maintenance factory. .
First, the structure of the ladle will be described with reference to FIG. In addition, a ladle is not limited to what is shown in FIG. The ladle includes a ladle for molten iron and a ladle for molten steel, but the present invention can be applied to either ladle. Hereinafter, molten iron and molten steel may be collectively referred to as molten metal.

  As shown in FIG. 1, the ladle 1 includes a bottomed iron skin 2 constituting a ladle body, and a refractory 3 provided on the inner wall of the iron skin 2. The iron skin 2 includes a floor portion 4 formed in an arc shape in a cross-sectional view, and a cylindrical body portion 5 extending from the floor portion 4 to one side (for example, upward). Specifically, the laying portion 4 has an arc shape that gradually rises upward from the central portion toward the outer (outer) direction, in other words, a bowl shape (a spherical surface in which the central portion 4a is recessed). Formed).

The refractory 3 is an indefinite shape such as a regular brick or castable. Permanent bricks with a fixed shape are constructed on the inner wall of the body 5 of the iron shell 2 and the inner wall of the floor 4, and castable and other irregular shapes are formed on the inner wall side of the permanent brick from the middle part of the body 5 to the floor 4. The material is cast or sprayed.
When such a ladle 1 is used, the base metal 8 is attached to the inner wall of the refractory 3 that is the opening (upper side) 7 of the ladle 1, for example, on the opening 7 side of the trunk 5. Or, the base metal 8 may adhere to the refractory 3 located in the longitudinal center of the trunk portion 5 of the ladle 1. In addition, the metal 8 adheres to the inner wall of the refractory 3 located on the laying part 4 of the ladle 1.

  The molten metal temperature when the molten metal is conveyed in the ladle 1 and the molten metal temperature when the molten metal is processed in the ladle 1 are often not much higher than the solidification temperature of the molten metal. Therefore, a part of the molten metal may solidify at the time of conveyance or processing, and may adhere to the refractory 3 (particularly, the refractory 3 close to the opening 7 side) and become the bare metal 8. In addition, even when the ladle 1 is not sufficiently warmed, due to heat removal from the refractory 3, even if the base metal 8 adheres even at a portion below the hot water surface (particularly, the refractory 3 of the floor portion 4). There is.

  If the metal 8 adheres to the inner wall (refractory 3) of the ladle 1, not only will the amount of molten metal charged into the ladle 1 decrease, but the center of gravity position of the ladle 1 will change. Therefore, when the ladle 1 is lifted by a crane or the like and transported, it may become unbalanced. Further, when the molten metal is poured out from the opening 7 of the ladle 1, the base metal 8 becomes an obstacle, and there is a possibility that the flow of the molten metal at the time of the molten metal changes and becomes an obstacle. Furthermore, when the molten metal is charged into the ladle 1, the molten metal may be cooled by the metal 8 to change the molten metal temperature. For this reason, it is necessary to periodically remove the metal 8 attached to the inner wall of the ladle 1.

When removing the metal 8 attached to the inner wall of the ladle 1, the metal 8 is immersed in the molten metal in the situation where the molten metal is contained in the ladle 1. Difficult to remove. Therefore, the removal of the metal 8 is performed in a state where there is no molten metal in the ladle 1.
Specifically, first, the ladle 1 containing no molten metal is transported to a ladle maintenance factory. And as shown in FIG. 2, it installs in the tilting apparatus 10 which tilts the ladle 1 conveyed to the ladle maintenance factory.

The tilting device 10 has a base 11 installed on the floor, a plurality of rollers 12 rotatably supported on the base 11, and is swingable by the rotation of the rollers 12. A ladle installation body 13 to be installed is provided.
The ladle installation body 13 includes a bottom portion 14 that has an arc shape on the bottom side and is supported so as to be able to swing by being grounded to the roller 12, and a pair of side portions 15 that stand upward from the bottom portion 14. ing. The side portion 15 is provided with a concave locking portion 17 that locks with a trunnion shaft of the ladle 1 or a protruding portion 16 provided on the outer surface of the ladle 1. Therefore, the ladle 1 can be installed on the ladle installation body 13 by locking the trunnion shaft or the protruding portion 16 of the ladle 1 to the locking portion 17.

  And after installing the ladle 1 in the ladle installation body 13, the ladle installation body 13 is swung by rotating the roller 12 that is in contact with the bottom 14 of the ladle installation body 13, so that the ladle Tilt 1 to a predetermined angle. The ladle installation body 13 is swung so that the opening 7 of the ladle 1 faces a machine 18 such as a backhoe that removes the metal 8. Then, after the ladle 1 is tilted to a predetermined angle, it is removed by applying a striking force, a pulling force or the like to the metal 8 attached to the refractory 3 of the ladle 1 using the machine 18.

  In addition, when removing the bullion 8, there is a method in which the bullion 8 is removed by fusing the bullion 8 with gas or the like. However, if the joint surface between the bullion 8 and the refractory 3 is melted, the refractory is removed. 3 may be easily melted, and a lot of heat energy such as gas is required for fusing, and smoke is generated. For this reason, in the present invention, instead of melting the bullion 8 with gas, the bullion 8 is mechanically repetitively given vibration (striking force) to the bullion 8 by the breaker 19 attached to the machine 18. The removal method is adopted. Alternatively, the bare metal is caught and removed by a peeler 20 (having a sharp portion at the tip) attached to the machine 18.

Thus, when removing the bullion 8, it is effective to remove the bullion 8 by striking or hooking, but in the ladle 1 immediately after the molten metal is discharged, the temperature of the bullion 8 is high. In some cases, even if an attempt is made to remove the bullion 8 in a state where the bullion temperature is high, it may not be removed.
Therefore, in the present invention, when removing the bullion 8, the bullion 8 is removed by striking or hooking after natural cooling or forced cooling so that the bullion temperature to be removed is 800 ° C. or less. .

When the bullion temperature exceeds 800 ° C., the strength of the bullion 8 is weak. For example, even if the bullion surface is hit, the bullion 8 is plastically deformed, and the impact is caused by the refractory and the bullion. It is difficult to transmit to the boundary with 8, and the bare metal 8 may be difficult to peel off from the refractory.
In addition, when the metal temperature is cooled to 800 ° C. or less, the metal 8 contracts, and the contraction rate between the metal 8 and the refractory increases, so that the metal 8 easily peels from the refractory. Table 1 summarizes the difference in shrinkage between pure iron and refractory, and FIG. 3 is a graph of the results in Table 1. The pure iron in Table 1 was obtained from the density shown in “C. Li, BGThomas: Met Trans 35B 1151 (2004)”.

  As shown in FIG. 3, when the temperature is high, there is not much difference in shrinkage between pure iron and refractory, but when the temperature is below about 1100 ° C., the difference in shrinkage suddenly increases and the difference in shrinkage is about 3%. It is. Further, as shown in FIG. 4, even if the carbon amount is changed, the average linear expansion coefficient is around 3, and the shrinkage amount is also in the range of 0.015 to 0.025, which varies greatly depending on the carbon amount. There is no. Thus, even if it sees from FIG.3 and FIG.4, if the base metal temperature shall be 800 degrees C or less, since the difference of the shrinkage | contraction rate of the base metal 8 and a refractory material will become large, if the base metal 8 is easy to remove Conceivable.

  Further, if the metal temperature is 800 ° C. or lower, the strength of the metal 8 increases, and the metal 8 becomes difficult to be plastically deformed. Therefore, the impact when the metal 8 is hit is refractory and metal. From this point, the base metal 8 is easily peeled off from the refractory. This is described in "High Temperature Deformation Progress Review of Iron and Steel, Steel Fundamental Joint Research Group, High Temperature Deformation Group Symposium Text, February 14, 1979".

In this way, the bullion 8 can be easily removed by applying a striking force to the bullion 8 after the bullion temperature is set to 800 ° C. or lower. The same applies to the case where the metal 8 is hooked.
Now, when removing the bullion 8, it is necessary to set the bullion temperature to 800 ° C. or less, but if the bullion 8 (refractory) is cooled too much, the ladle temperature (refractory temperature) will decrease. When the ladle is used after maintenance, it takes time and effort to heat the ladle, and much energy is required to heat the ladle. Moreover, when the time which heats a ladle cannot be ensured on an operation and it is underheating, the expansion of the refractory 3 will be insufficient. As a result, there is a concern that the molten metal enters a gap such as a joint of the refractory 3 and leaks steel. In addition, unless the lower limit temperature at the time of removing the bullion is set to 300 ° C., when the amorphous refractory is sprayed after the bullion is removed, the water may not be sufficiently evaporated and the spraying operation may not be performed properly. In other words, unless the lower limit temperature at the time of removing the bullion is set to 300 ° C. or higher, there is a possibility that the adhesion rate of the amorphous refractory when the spraying operation is performed is deteriorated.

  Thus, when removing the bullion 8, it is preferable to apply the striking force of the breaker 19 or the like to the bullion 8 whose bullion temperature is in the range of 800 ° C. to 300 ° C. for removal. In addition, when giving a striking force to the bullion 8, it is preferable not to give a striking force toward the refractory 3 to which the bullion 8 is attached, but to give a striking force to the side opposite to the refractory. In other words, it is preferable that the direction in which the impact force is applied does not overlap with the refractory to which the base metal 8 is attached, but the direction in which the impact force is applied does not overlap with the refractory to which the base metal 8 is attached. For example, the base metal 8 is hit from above and below along the inner wall of the refractory 3 of the ladle 1.

  Table 2 summarizes an example in which the bullion 8 was removed by the method of removing the bullion of the ladle of the present invention and a comparative example in which the bullion 8 was removed by a method different from the present invention. Is.

  The examples and comparative examples shown in Table 2 show examples in which both a ladle for molten iron and a ladle for molten steel are used. In addition, the operation column in Table 2 simply shows the work for removing the bullion 8. “Hot metal or molten steel is dispensed” indicates whether or not the metal 8 has been removed by removal, and the “surface temperature of the metal” indicates the temperature of the metal 8 to be removed (metal temperature). It is shown. The bare metal temperature was measured in a non-contact manner using a thermo viewer as usual by those skilled in the art.

  “Presence / absence of removal by machine” indicates whether or not the bullion 8 has been removed by the machine 18 such as the backhoe as described above. In contrast, it indicates whether or not removal has been performed by hitting. “Direction of striking” indicates whether or not striking force is applied upward, that is, on the side opposite to the refractory when striking the bullion 8. In the determination column, a case where the content of the operation matches the content shown in the determination is determined as “good”, and a case where the content does not match is determined as “bad”.

The bullion adhesion amount W1 indicates the total adhesion amount of the bullion 8 adhering to the ladle 1, and the weight of the ladle 1 before the bullion 8 adheres (immediately after the last maintenance is completed). The difference between the weight of the ladle 1) and the weight of the ladle 1 after the metal 8 is attached (the weight of the ladle 1 immediately before the start of the current maintenance) is shown. The weight of the ladle or the like was measured with a weight meter such as a load cell.
The bullion removal amount W2 indicates the removal amount of the bullion 8 after maintenance, and indicates the difference between the weight of the ladle 1 immediately before the start of maintenance and the weight of the ladle 1 immediately after the completion of maintenance. is there. The bullion removal rate R indicates the rate at which the bullion 8 has been removed, and is the bullion removal amount W2 divided by the bullion removal amount W1 (R = W2 / W1). The spraying material fixing rate indicates a fixed ratio with respect to the area of the refractory material laid on the ladle laying part after the base metal 8 is removed. That is, the spraying material fixing rate can be obtained by dividing the area of the new spraying material fixed on the laying part after spraying the refractory by the area of the laying part of the ladle. In this embodiment, after maintenance, the area of a new spraying material was determined visually to obtain the spraying material fixing rate. As the spray material, for example, a material containing Al ₂ O ₃ : 61 mass%, SiO ₂ : 18 mass%, SiC: 11 mass%, C: 3 mass%, and others: 7 mass% was used. Of course, the spray material is not limited to this.

As shown in Example 1 to Example 10, whether it is a ladle 1 for molten iron or a ladle 1 for molten steel, the bullion 8 when the bullion temperature is 800 ° C. to 300 ° C. In addition to the removal of the metal 8 and the removal of the metal 8 by the machine 18, the metal removal rate R and the spraying material fixing rate can be improved as compared with the comparative example.
FIG. 5 summarizes the metal removal rate and the spraying material fixing rate with respect to the metal temperature when the ladle for hot metal is prepared in the examples and comparative examples. FIG. 6 summarizes the bullion removal rate and the spraying material fixing rate with respect to the bullion temperature when a ladle for molten steel is prepared in the examples and comparative examples.

  As shown in FIGS. 5 and 6, when the bullion temperature becomes higher than 800 ° C., the bullion removal rate R tends to decrease rapidly, and when the bullion temperature becomes lower than 300 ° C., the spraying material fixing rate. It tends to decrease sharply. That is, when removing the bullion 8, the bullion temperature needs to be within a range from 800 ° C. to 300 ° C. Thus, the bullion 8 can be efficiently removed and the spraying material is fixed. Can also be improved.

  As mentioned above, according to this invention, when removing the ingot 8 adhering to the ladle 1 used in the steelmaking factory, after discharging the molten metal from the ladle 1, the ingot temperature to be removed is 800 ° C.- By removing the bullion 8 mechanically at 300 ° C., the removal rate of the removed bullion can be improved and the fixing rate of the spraying material performed after the bullion removal can be improved. it can.

  It should be noted that matters not explicitly disclosed in the embodiment disclosed this time, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component, deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.

DESCRIPTION OF SYMBOLS 1 Ladle 2 Iron skin 3 Refractory 4 Laying part 5 Trunk part 7 Opening part 8 Base metal 10 Tilt device 11 Base stand 12 Roller 13 Ladle installation body 14 Bottom part 15 Side part 16 Protrusion part 17 Locking part 18 Machine 19 Breaker R bullion removal rate W1 bullion adhesion amount W2 bullion removal amount

Claims (1)

When removing the bullion attached to the refractory of the ladle for steel making, after discharging the molten metal in the ladle, the bullion is hit or caught when the bullion temperature to be removed is 800 ° C to 300 ° C. A method for removing the bullion from the ladle.

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