JP7493413B2 - A method for separating solidified metal lumps in a molten metal ladle - Google Patents

Description

The present invention relates to a method for separating a solidified metal lump, which is a lump of molten metal that has solidified and is surrounded by a refractory material present inside the iron shell of a molten metal ladle, from the iron shell.

In steelworks and other places, molten metal ladles (sometimes called ladles or molten metal ladles) are used, such as molten pig iron ladles for transporting molten pig iron, molten steel ladles for transporting molten steel, and tundishes used when pouring molten steel into a mold. Molten metal ladles are constructed with refractory materials such as firebricks lined on the inside of the steel shell to withstand the high temperature of the molten metal that is brought in.

When a steelmaking process is stopped for an extended period of time to ensure safety in the event of a power outage caused by a natural disaster such as an earthquake or lightning strike, the molten metal contained in the molten metal ladle solidifies and becomes a lump. Molten metal ladles take a long time to prepare and are dedicated to each operating process. Therefore, in order to quickly resume operations, it is preferable to reuse the molten metal ladle with the solidified molten metal inside. In order to reuse the molten metal ladle, it is necessary to at least remove the molten metal that has solidified inside the molten metal ladle. However, removing the solidified lump of molten metal is very time-consuming and takes a long time to complete, so this is not usually done.

The following patent documents 1 and 2 disclose known techniques for dismantling and removing solidified metal lumps from inside a vessel. Patent document 1 discloses a technique for dismantling residual pig iron inside a blast furnace. In this technique, the firebricks surrounding the periphery of the residual pig iron are removed and replaced with sand or the like, and the residual pig iron is destroyed by blasting using this sand as a cushioning material.

Patent Document 2 also discloses a technique for dismantling and removing refractory bricks inside a blast furnace. In this technique, the refractory bricks are removed by spraying a mixed fluid of an abrasive and high-pressure water.

Patent No. 4932972 Japanese Patent Application Laid-Open No. 9-53107

As mentioned above, it has been desirable to reuse molten metal ladles by removing the solidified lumps of molten metal. The technology disclosed in the above Patent Document 1 uses blasting demolition, which is likely to damage the vessel, the blast furnace. Furthermore, the technology disclosed in the above Patent Document 2 requires that the firebricks are exposed and that a mixed fluid consisting of an abrasive and high-pressure water can be directly sprayed onto them. Therefore, it is not easy to apply these technologies to molten metal ladles.

In order to reuse a ladle for molten metal, it is necessary to separate (remove) at least the solidified lump of molten metal, i.e., the solidified metal lump, from the ladle for molten metal. However, it is not enough to simply separate the solidified metal lump from the ladle for molten metal; the separation work must be carried out in a way that causes as little damage or other defects to the iron shell of the ladle for molten metal as possible. If it is possible to separate the solidified metal lump from the ladle for molten metal without causing any defects such as damage to the iron shell of the ladle for molten metal, then the ladle for molten metal can be reused by subsequently carrying out simple work (such as re-lining the refractory material, etc.).

In view of the above, the present invention aims to provide a method for separating solidified lumps of molten metal that can make the ladle for molten metal easier to reuse by removing the solidified lumps of molten metal while causing minimal defects to the iron shell of the ladle for molten metal.

The method of the present invention is a method for separating a solidified metal lump, which is a lump of molten metal that has solidified and is surrounded by a refractory material present inside the iron shell of a molten metal ladle, from the iron shell, and is characterized by comprising the steps of forming holes at intervals around the entire circumference of the refractory material, the holes extending from the top surface of the refractory material to the bottom, and lifting the solidified metal lump relative to the iron shell to separate the solidified metal lump from the iron shell.

According to the method of the present invention, the solidified metal mass is separated from the steel shell, so that the steel shell can be reused to reproduce (reuse) a new ladle for molten metal. More specifically, the holes formed in the refractory do not reach the steel shell, and when the solidified metal mass and the steel shell are separated, the refractory is merely broken, so that the steel shell is not damaged or otherwise damaged. Therefore, after the solidified metal mass is separated, the refractory can be replaced inside the molten metal pot (i.e., the refractory remaining inside the molten metal pot is removed, and then new refractory is placed inside the molten metal pot), so that the molten metal pot can be reused well. In other words, the method of the present invention makes it possible to make the molten metal pot in a state that is easy to reuse. In addition, since the holes are formed in the refractory at intervals, it is possible to reduce the work of forming holes compared to the case of forming holes continuously, and it is also easy to form holes at a specified position without tilting.

In the method of the present invention, for example, the bottom of the refractory may be a portion within a range of height from the inner bottom surface of the iron shell of the molten metal ladle to the upper end surface of the refractory covering the bottom surface.

In this case, damage to the inner bottom surface of the iron shell of the molten metal ladle can be more reliably prevented.

It is preferable that the method of the present invention further includes a step of breaking the gaps between the holes formed in the refractory material by injecting high-pressure water.

In this case, by injecting high-pressure water, it is possible to easily break the gap between the holes formed in the refractory. Furthermore, by breaking this portion, there is less refractory to break in the process of separating the solidified metal lump from the steel shell, making it possible to reduce the force required to pull up the solidified metal lump.

In the method of the present invention, it is also preferable to install an anchor in the solidified metal mass and use the anchor to lift the solidified metal mass up against the steel shell.

In this case, it becomes possible to facilitate the task of lifting the solidified metal block onto the steel shell.

In addition, in the method of the present invention, after the solidified metal mass is separated from the iron shell, the refractory remaining inside the molten metal ladle may be removed, and then new refractory may be placed inside the iron shell of the molten metal ladle.

In this case, the molten metal ladle can be reused simply by replacing the refractory lining.

As described above, according to the above aspects of the present invention, by removing the solidified lumps of molten metal in a manner that causes minimal defects to the casing of the molten metal ladle, it is possible to make the molten metal ladle in a state that is easy to reuse.

FIG. 2 is a schematic horizontal cross-sectional view showing a state in which a hole is formed in a refractory material of a ladle for molten metal with a solidified metal lump remaining therein according to an embodiment of the present invention. FIG. 2 is a schematic vertical cross-sectional view showing a state in which a solidified metal lump remains inside a refractory material of a ladle for molten metal and forms a hole therein. FIG. 4 is a schematic horizontal cross-sectional view showing a state in which a refractory material existing between adjacent holes is broken. FIG. 4 is a schematic vertical cross-sectional view showing a state in which the refractory material existing between adjacent holes is broken and a state in which the solidified metal lump is pulled up.

The method according to the embodiment of the present invention will be described with reference to the drawings.

The molten metal ladle 10 is a container for storing molten metal in steelworks and the like, such as a molten pig iron ladle for transporting molten pig iron, a molten steel ladle for transporting molten steel, and a tundish used when pouring molten steel into a mold, and is also called a ladle, molten metal ladle, molten metal container, etc.

As shown in Figures 1 and 2, the ladle 10 for molten metal is constructed by attaching a refractory material 12, such as firebricks, to the inside of the steel shell 11 so that it can withstand the high temperature of the molten metal that is brought in. The ladle 10 for molten metal is open at the top, and the molten metal is poured in through this opening. Here, the ladle 10 for molten metal is roughly cylindrical with an open top, but its shape varies depending on the application, etc. Also, a lining material, etc. may be present between the steel shell 11 and the refractory material 12.

When a steelworks or the like is forced to suspend operations for an extended period of time to ensure safety due to a power outage or other reason, molten metal such as molten pig iron or molten steel solidifies, and the solidified molten metal remains inside the refractory material 12 as a lump (hereinafter referred to as the solidified metal lump) A.

The present invention relates to a method for separating a solidified metal mass A remaining in a ladle for molten metal 10 from the iron shell 11 in order to reuse the iron shell 11 and reproduce the ladle for molten metal 10. The method includes a drilling process, a breaking process, and a lifting process.

First, a drilling process is performed in which adjacent holes 12a are drilled at a predetermined interval around the entire circumference of the opening side of the refractory 12 using a drilling device 20. The holes 12a are formed at least until they reach the top surface of the refractory 11 located at the bottom. As a result, discontinuous holes 12a are formed around the entire circumference on the outside of the solidified metal mass A. The bottom of the refractory 12 is a part within the height range from the inner bottom surface of the iron shell 11 of the molten metal ladle 10 to the upper end surface of the refractory 11 covering the bottom surface. In this case, damage to the inner bottom surface of the iron shell 11 of the molten metal ladle 10 can be more reliably prevented. Note that the holes 12a are preferably formed just before reaching the inner surface of the iron shell 11 so as not to damage the iron shell 11. Furthermore, the holes 12a are preferably provided in the approximately central part of the thickness direction of the refractory 12.

It is preferable that the diameter of the hole 12a is less than the thickness of the refractory material 12 so as not to damage the shell 11 and to allow the shell 11 to be reused satisfactorily. It is also preferable not to cut the solidified metal block A so as not to damage the hole-drilling device 20.

In this application, hole 12a refers to a hole opened in one drilling operation using one drilling device 20. Although not shown, if one drilling device is equipped with multiple bits and multiple consecutive holes are opened in one drilling operation, these multiple consecutive holes are collectively referred to as one hole in this application.

If the holes 12a are opened continuously without any gaps, there is a high possibility that the holes 12a opened later will be formed at an angle toward the already opened holes 12a, which is undesirable. The interval between adjacent holes 12a may be determined so that the holes 12a can be broken and reliably connected in the breaking process. The interval between adjacent holes 12a may be different as long as it is equal to or smaller than this interval, and may be larger or smaller than the diameter of the holes 12a.

As the drilling device 20, it is preferable to use a crawler drill 20, which is used, for example, when drilling blasting holes for filling rock with explosives such as dynamite in mountain tunnel construction. The crawler drill 20 may be installed so as to be able to run on a work platform 30 that is at the same height as the top end of the molten metal ladle 10, for example.

The crawler drill 20 is a crawler-type running body 21 equipped with a drilling device 22. Here, a guide post 24 is attached to the tip of a rotating arm 23 installed on the running body 21, and a drilling machine 25 that drills holes by striking force and rotation is configured to move forward and backward along this guide post 24.

The drilling machine 25 is equipped with a drifter 26 slidably mounted on the guide pillar 24, and this drifter 26 has a mechanism for striking and rotating a hollow rod 27, and compressed air is supplied through the hollow rod 27 and discharged from an air outlet of a bit 28 at the tip of the rod. As a result, the striking force and rotation force of the bit 28 perforate the refractory A ground and blow away the pulverized powder. The pulverized powder blown up to the top of the hole 12a is preferably sucked up and collected by a vacuum (not shown).

Next, as shown in Figures 3 and 4, a breaking process is performed to break the refractory 12 present in the adjacent holes 12a. In this breaking process, the refractory 12 present in the adjacent holes 12a is broken to create a gap 12b around the entire circumference between the steel shell 11 and the solidified metal mass A. However, there may be a portion between the steel shell 11 and the solidified metal mass A where the refractory 12 is continuous without being broken.

The refractory material 12 is preferably broken by injecting high-pressure water. Specifically, a high-pressure water injection device 40, which is used to make notches on both sides of a blast hole in mountain tunnel construction, is used, and the refractory material 12 is broken by injecting high-pressure water with the high-pressure water injection device 40 inserted into the hole 12a.

The high-pressure water injection device 40 may be, for example, a rod-shaped lance 41 that also serves as a water supply pipe, with an injection section 42 having high-pressure water injection holes formed in two directions, left and right, at the tip of the lance. When using a high-pressure water injection device 40 that injects high-pressure water in both directions like this, inserting it into one hole 12a can break the refractory material 12 that exists between adjacent holes 12a in both directions, so it is only necessary to insert the high-pressure water injection device 40 into every other hole 12a, resulting in excellent work efficiency. The pressure of the injected high-pressure water is set to a level that can break the refractory material 12.

It is preferable that the high-pressure water injection device 40 moves from the bottom of the hole 12a upward in a sequential and continuous manner while injecting high-pressure water. This allows the refractory 12 remaining between adjacent holes 12a to be broken by forming a gap 12b over the entire length of the refractory 12. In addition, since the movement is easier than moving from the top of the hole 12a downward in a sequential and continuous manner while injecting high-pressure water, it is possible to simplify the work. For safety reasons, it is preferable that the high-pressure water injection device 40 stops injecting high-pressure water below the upper surface of the refractory 12 so that workers working on the upper surface of the refractory 12 do not come into contact with the high-pressure water and get injured.

The fracturing process may be performed simultaneously with the pulling process. In other words, the gaps 12b may not be formed with high-pressure water, and instead, when the solidified metal block A is pulled up in the pulling process, gaps 12b may be generated in the refractory 12 between adjacent holes 12a, causing the refractory 12 to break.

Next, a pulling process is performed in which the solidified metal lump A is pulled up against the shell 11. In this pulling process, the solidified metal lump A, together with the refractory 12 remaining on its outer peripheral surface, is pulled up against the outer shell 11 and the refractory 12 remaining on its inner peripheral surface, thereby separating them. At the start of the pulling process, the refractory 12 remains over almost the entire surface between the bottom surface of the solidified metal lump A and the top surface of the bottom of the shell 11. The solidified metal lump A is pulled up using a pulling device 50, such as a large crane, so that the remaining refractory 12 is broken by being torn off or ripped apart.

The steel shell 11 separated from the solidified metal mass A is free of defects such as breakage, and can be easily reused after removing the refractory material 12 remaining on the inner surface. Note that in Figure 4, the high-pressure water injection device 40 used in the breaking process and the lifting device 50 used in the lifting process are both present, but this is merely an illustration and they are not used together.

It is preferable to install an anchor 51 in the solidified metal lump A and use this anchor 51 to pull up the solidified metal lump A with the lifting device 50. For example, if the solidified metal lump A is a lump of solidified molten steel, the anchor 51 may be installed in the solidified metal lump A by welding. Also, if the solidified metal lump A is a lump of solidified pig iron, the anchor 51 may be installed in the solidified metal lump A using a chemical anchor (registered trademark) that forms a hole in the solidified metal lump A, inserts a capsule containing a solvent into the hole, and breaks the capsule with the anchor 51, causing a chemical reaction of the solvent to fix the anchor 51.

Although not shown, it is also preferable to install an expansion device such as a jack in the hole 12a formed in the refractory 12 in the drilling process or in the gap 12b in the refractory 12 broken in the breaking process, and widen the hole 12a or the gap 12b in the refractory 12, thereby breaking at least a portion of the refractory 12 remaining between the bottom surface of the solidified metal lump A and the upper surface of the bottom of the shell 11. Furthermore, it is also preferable to install an expansion device such as a jack between the anchor 51 installed in the solidified metal lump A and the shell 11, and widen the gap between them, thereby breaking at least a portion of the remaining refractory 12.

In the pulling process, if a pulling device 50 capable of pulling up the solidified metal lump A cannot be prepared, or if a pulling device 50 having a pulling force sufficient to break the refractory material 12 remaining between the bottom surface of the solidified metal lump A and the upper surface of the bottom of the steel shell 11 cannot be prepared, the solidified metal lump A can be cut into multiple pieces. In this case, the solidified metal lump A is cut over its entire height using a cutting device (e.g., a wire saw) capable of cutting the solidified metal lump A.

Then, anchors 51 or the like are placed on each of the cut solidified metal blocks, and the solidified metal blocks are pulled up using a lifting device 50, breaking the refractory material 12 remaining between the bottom surface of each solidified metal block and the top surface of the bottom of the steel shell 11, and the individual solidified metal blocks are pulled up individually.

According to the method of this embodiment, as described above, the solidified metal lump A is separated from the steel shell 11, so that it is possible to re-produce (reuse) a new molten metal ladle 10 by reusing the steel shell 11. More specifically, the hole 12a formed in the refractory 12 does not reach the steel shell 11, and when the breaking process and the pulling process for separating the solidified metal lump A from the steel shell 11 are performed, the refractory 12 is only broken, so that the steel shell 11 does not suffer from defects such as damage. Therefore, the refractory 12 can be replaced inside the molten metal ladle 10 thereafter (i.e., the refractory 12 remaining inside the molten metal ladle 10 is removed, and then a new refractory 12 is placed inside the molten metal ladle 10), so that the molten metal ladle 10 can be reused satisfactorily. In other words, by removing the solidified metal lump A according to this embodiment, it is possible to make the molten metal ladle 10 in a state where it is easy to reuse it.

The present invention is not limited to the method specifically described in the above embodiment, and can be modified as appropriate within the scope of the claims. For example, the drilling device 20 does not necessarily have to be a crawler drill, but may be a slot drill or a core cutter. Also, the running body 21 is not necessarily required, and it is sufficient that the drilling machine 25 is in a form that can be moved and installed.

10...Lan for molten metal, 11...Shell, 12...Refractory material, 12a...Hole, 12b...Gap, 20...Drilling device, crawler drill, 21...Traveling body, 22...Drilling device, 23...Swivel arm, 24...Guide column, 25...Drilling machine, 26...Drifter display unit, 27...Hollow rod, 28...Bid, 30...Work platform, 40...High pressure water jetting device, 41...Lance, 42...Jetting unit, 50...Lifting device, 51...Anchor, A...Solidified metal block.

Claims (5)

1. A method for separating a solidified metal lump, which is a lump of molten metal surrounded by a refractory material present inside a shell of a molten metal ladle, from the shell, comprising the steps of:
forming spaced apart holes around the entire circumference of the refractory body, the holes extending from the top surface of the refractory body to the bottom surface of the refractory body;
a step of lifting the solidified metal lump relative to the iron shell to separate the solidified metal lump from the iron shell. The method for separating solidified metal blocks according to claim 1, characterized in that the bottom of the refractory is a portion within a range of height from the inner bottom surface of the iron shell of the molten metal ladle to the upper end surface of the refractory covering the bottom surface. The method for separating solidified metal blocks according to claim 1 or 2, further comprising a step of breaking the gaps between the holes formed in the refractory by injecting high-pressure water. The method for separating solidified metal blocks according to any one of claims 1 to 3, characterized in that an anchor is placed on the solidified metal block, and the solidified metal block is pulled up against the steel shell using the anchor. The method for separating solidified metal lump according to any one of claims 1 to 4, characterized in that after the solidified metal lump is separated from the iron shell, the refractory remaining inside the molten metal ladle is removed, and then new refractory is placed inside the iron shell of the molten metal ladle.

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