JP2967256B2 - Method for melting and removing solids such as ingots and slag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal container and a method for melting and removing solidified substances such as slag and slag which adhere to and stay in a molten metal container during operation.

[0002]

2. Description of the Related Art In a molten metal container such as a converter, a ladle, a degassing furnace, and ancillary facilities thereof, in operation, ingots, slag, and the like adhere and solidify, or float and stagnate on a molten metal surface.
This is an obstacle to charging of raw materials, moving containers, sampling of molten metal, measuring temperature, and dismantling. As a method of removing the solidified material, a method of injecting oxygen from the iron pipe to the surface of the solidified material, igniting and burning the steel pipe, heating and melting the solidified material by the combustion heat, and causing the solidified material to flow by injection of oxygen. Generally done. However, when the solidified material itself is in a high temperature state, it acts as an ignition source. However, when the solidified material is at a low temperature, the iron pipe cannot be ignited, so that the solidified material cannot be melted and removed.

[0003] Further, a removal method is also practiced in which an object is hit against the solidified material and the solidified material is separated from the adhered surface by the impact force. The method of hitting an object is simple and requires a large amount of removal per unit of time.However, if the solidified object is firmly adhered, the solid object is separated and removed only by the impact force applied to the object. In addition to the problem, not only can the base material with the solidified material be deformed or damaged by an impact at the time of removal, but also there is a problem.

[0004] Therefore, the temperature of the solidified material is maintained at a temperature equal to or higher than the melting temperature of the solidified material by the flame of the fuel gas, and at the same time, the amount of the molten material is increased by burning the injected iron powder to raise the temperature of the solidified material. Japanese Patent Application Laid-Open No. 2-28709 discloses a method of spraying a molten material formed on the surface of a solidified material to remove a melt.
No. 2 proposes this. However, this method requires a relatively long time, and a quicker method for removing solids is expected.

[0005]

In the prior art, the work efficiency and the removal speed greatly differ depending on the temperature of the solidified material to be removed or the state of attachment on the attachment surface, and a stable removal operation cannot be performed. That is, in the method of injecting oxygen from the iron pipe, when the solidified material temperature decreases, the iron pipe does not ignite and the solidified material cannot be removed.

In the method of hitting a certain object, if the solidified material and the base material are strongly adhered to each other, not only the solidified material cannot be removed, but also it is difficult to remove the solidified material. There is a problem such as damaging the base material with the mark.

Further, in the method of injecting the combustion temperature of the flame of the fuel gas and the iron powder and the oxygen, it is necessary to further improve the solid removal rate. The present invention relates to the temperature of the solidified product,
It is an object of the present invention to provide a removal method that can obtain a high-speed and stable removal rate without being affected by an attached state and a floating state.

[0008]

SUMMARY OF THE INVENTION The present invention has been provided to solve the above problems, and the gist of the invention is as follows.
It is as follows. (1) A method in which a material hole is disposed at the center and a plurality of fuel gas injection holes are provided around the hole in multiple stages around concentric circles of the material hole to melt and remove solidified materials such as ingots and slag. A fuel gas is injected from the injection hole, and a mixed material comprising 15-60 wt% of metal aluminum having a particle size of 0.15 mm or less and a balance of iron oxide having a particle size of 0.4 mm or less is injected from the material hole to form a metal or slag. It is characterized by solidification such as melting. (2) A material hole is arranged at the center, a plurality of fuel gas injection holes are provided around the material hole in multiple stages on a concentric circle of the material hole, and a plurality of gas injection holes are provided between the material hole and the innermost fuel gas injection hole. In the method of melting and removing solids such as ingots and slag by providing injection holes, a fuel gas is injected from fuel gas injection holes and metal aluminum having a particle size of 0.15 mm or less from material holes.
Injecting a mixed material consisting of iron oxide having a particle size of 0.4 mm or less with the balance being 0.4% by weight and removing the solidified material surface so that the gas flow rate from the gas injection hole to the gas injection hole outlet is 100 m / sec or more. To melt and remove solidified materials such as ingots and slag.

[0009]

According to the method of the present invention, a mixed material of metallic aluminum and iron oxide is attached or sprayed onto a solidified material such as metal slag on a molten metal surface together with the flame of the fuel gas, thereby instantaneously solidifying the solidified material. Is melted, and the resulting melt has a low viscosity, so that the melt itself flows and exposes a new solidified surface, whereby a stable removal rate can be obtained.

That is, the surface temperature of the solidified material is raised to the temperature at which the mixed material of metal aluminum and iron oxide is ignited by the flame of the fuel gas, and the metal aluminum and iron oxide heated when the fuel gas passes through the flame are deposited on the surface of the solidified material. Combustion occurs at the same time as collision, producing high temperatures. Since the combustion temperature of metal aluminum and iron oxide is sufficiently higher than the solidification temperature generated in the molten metal container,
The viscosity of the resulting melt decreases, and the melt readily flows to expose a new solidified surface. A high-speed and stable removal rate can be obtained by repeating the above melting and flow.
In the situation where the flow of the melt is obstructed, the gas is sprayed on the melt and scattered.However, the viscosity of the melt is low and can be easily scattered, and the removal speed is continuously reduced without drastically decreasing the removal rate. Can be removed.

In the present invention, the particle size of metallic aluminum of the mixed material is 0.02 to 0.15 mm, and the particle size of iron oxide is 0.1 to 0.1 mm.
The thickness is preferably 1 to 0.4 mm from the viewpoint of improving the combustion efficiency when metal aluminum and iron oxide collide with the surface of the solidified material. That is, when the particle diameter of the metal aluminum is less than 0.02 mm, the amount of the metal aluminum that scatters out of the flame when the fuel gas passes through the flame and collides with the solidified material is insufficient, so that the combustion efficiency is reduced.

On the other hand, if the particle diameter of the metal aluminum exceeds 0.15 mm, the heating of the fuel gas during the passage of the flame becomes insufficient, so that the temperature of the metal aluminum at the time of solidified collision is low and the combustion efficiency is reduced. Further, in order to maintain the combustion efficiency at a high level, the metal aluminum preferably has a particle size of 0.03 to 0.1 mm. If the particle size of the iron oxide is less than 0.1 mm, the combustion of the iron oxide and metallic aluminum starts immediately after the injection of the mixed material in the flame of the fuel gas, and the combustion in the flame up to the collision with the solidified material is almost completed. The effective combustion efficiency for removal is reduced. If the particle size of the iron oxide exceeds 0.4 mm, the heating of the fuel gas during the passage of the flame becomes insufficient, so that the temperature of the iron oxide at the time of solidified collision is low and the combustion efficiency is reduced. In addition, since the rebound amount at the time of solidified matter collision increases and the amount of iron oxide at the time of solidified matter collision becomes insufficient, the combustion efficiency is reduced. It is preferably about 0.3 mm.

Also, the mixed material of metallic aluminum is 15 to 60.
In terms of wt% and the remainder being iron oxide, it is preferable to improve the removal rate when metal aluminum and iron oxide collide with the solidified material surface. That is, the metal aluminum of the mixed material is 15
When the content is less than wt% and the balance is iron oxide, the metal aluminum undergoes an oxidation reaction in its entirety, but at the same time, the molten iron oxide adheres to the surface of the solidified material to inhibit the removal, so that the removal rate is reduced. Further, when the metal aluminum exceeds 60 wt% and the balance is iron oxide, the unreacted molten metal aluminum adheres to the surface of the solidified material and hinders the removal, so that the removal rate is reduced. In order to further maintain the removal speed at a high level, metal aluminum 30 to 50 w
It is preferably t%.

The flow velocity of the gas injected from the gas injection holes is 100
m / sec or more is preferable since the scattering efficiency of the generated melt is improved. That is, the gas flow rate 100
If it is less than m / sec, the entire amount of the generated melt cannot be scattered and stays in the removing portion, so that the removing speed is reduced. At a gas flow rate of 100 m / sec or more, the entire amount of the generated melt can be scattered, and the removal portion is constantly exposed to a new solidified material, so that the removal speed is stable.

Since the purpose of the injection gas is to scatter the molten material, it is important to spray the concentrated gas on the molten material. Injecting gas when the melt is not staying is not only wasteful, but also reduces the removal rate because the removal part is cooled. Therefore, the gas injection site, the gas injection amount, the gas injection time, and the like may be appropriately selected depending on the state of stay of the solidified matter. In the present invention, the gas flow rate is not specified, but may be usually 250 m / sec or less from the viewpoint of reducing the capacity of the blower or the cost of the blowing power in the normal removal step.

Table 1 shows a solidified material melting and removing method in which a mixed material of metallic aluminum and iron oxide is injected together with a fuel gas.
It shows the relationship between the particle size and mixing ratio of metal aluminum and iron oxide and the removal rate thereof. The experimental conditions are as shown in the lower part of Table 1.

In the conditions 1 to 3 in the table, solids were removed by changing the distance between the solids and the removing device. The distance at which the removal rate was the largest was 800 mm in Condition 2, and the removal rate was reduced even if the removal apparatus was moved closer or further than 800 mm. In the conditions 4 to 9 in the table, the solidified material was removed by changing the particle size of metallic aluminum at a distance of 800 mm (condition 2) at which the removal rate was large in conditions 1 to 3.

The particle diameter of the metal aluminum having a large removal rate is 0.02 to 0.15 mm in the condition 5 to the condition 8, and if it is out of this range, the removal rate is reduced. In the table, the conditions 10 to 15 correspond to the distance 800 mm (condition 2) and the metal aluminum particle diameter 0.06 mm (condition 7) at which the removal rate was large in the conditions 1 to 3 and the conditions 4 to 9 and the particle diameter of the iron oxide was reduced. The solidified material was removed in a different manner. The particle diameter of the iron oxide having a large removal rate is 0.15 to 0.4 mm in the condition 10 to the condition 15
If the condition 7 is outside the above range at 0.1 mm, the removal rate is reduced.

In the table, conditions 16 to 22 correspond to conditions 1 to 3; conditions 4 to 9 and conditions 10 to 15 have a distance 800 mm (condition 2) at which the removal rate is large, and a particle diameter of metal aluminum of 0.06 mm (condition 2). Solidification was removed by changing the mixing ratio of metallic aluminum under condition 7) and a particle size of iron oxide of 0.2 mm (condition 12). The mixing ratio of the metal aluminum having a high removal rate is 15 to 60 in the condition 17 to the condition 21.
If it is out of this range in%, the removal rate decreases. As the iron oxide, any one of FeO, Fe ₂ O ₃ , and Fe ₃ O ₄ or a combination of two or more thereof may be used. Preferably, Fe ₂ O ₃ is good. The fuel gas is not limited to propane-oxygen, and the solidified material can be instantaneously heated to the ignition temperature of the mixed material of metallic aluminum and iron oxide, and the mixed material of metallic aluminum and iron oxide can be heated in the fuel gas flame. It can be heated to ignite instantly on the solidified surface, for example, acetylene-
It may be oxygen, COG-oxygen, propane-air, acetylene-air, COG-air, or the like.

[0020]

[Table 1]

Table 2 shows the particle size and the mixing ratio of metal aluminum and iron oxide in the method for removing solidified material by injecting a fuel gas, a mixed material of metal aluminum and iron oxide and injecting the gas.
The relationship between the flow rate of the injected gas and the removal rate is shown as the same as the condition 12 above. The experimental conditions are as shown in the lower part of Table 2.

From condition 23 to condition 25 in the table, the solidified material was removed by changing the distance between the solidified material and the removing device. The distance at which the removal rate was the largest was 500 mm in the condition 24 of 500 mm.
The removal rate decreases even if the removal device is moved closer or further than m. In the table, conditions 26 to 30 correspond to conditions 23 to 2
Distance 500mm where removal speed was large in 5 (condition 24)
The solidified material was removed by changing the flow rate of the injection gas. If the jet gas flow velocity at which the removal rate was large is 100 to 140 m / sec in the conditions 28 to 30 and is smaller than 100 m / sec, the removal rate decreases.

In the table, the condition 31 is the distance 500 mm (condition 24) at which the removal rate was the largest under the conditions 23 to 25 and the conditions 26 to 30 and the injection gas flow rate 140 m / s.
At ec (condition 30), the injection gas was continuously injected to remove solidified matter. When gas is continuously injected, the removal rate is lower than when intermittently injected.

The injection gas is not limited to oxygen, but may be any gas that can scatter the melt, such as air and nitrogen. The removal rate can be improved by inclining the injection direction of the injection gas so as to concentrate on the direction in which the melt is generated. The fuel gas is not limited to propane-oxygen, and the solidified material can be instantaneously heated to the ignition temperature of the mixed material of metallic aluminum and iron oxide, and the mixed material of metallic aluminum and iron oxide can be heated in the fuel gas flame. Can be heated to ignite instantly on the solidified surface, eg acetylene-oxygen, COG
-Oxygen, propane-air, acetylene-air, COG-
It may be air or the like.

[0025]

[Table 2]

[0026]

FIG. 3 is a sectional view (a) and a front view (b) of a removing apparatus according to a first embodiment for carrying out the method of the present invention.
In FIG. 3, the removing device 6 for injecting the mixed material of metallic aluminum and iron oxide and the fuel gas arranges the material hole 1 for injecting the mixed material of metallic aluminum and iron oxide at the center.
A plurality of fuel gas injection holes 2 are provided around the concentric circle of the material hole 1 in multiple stages. The material hole 1 is arranged at the center of the removing device 6 in order to cause the mixed material of metallic aluminum and iron oxide to concentrate and collide with the solidified material surface by the carrier gas. The fuel gas injection hole 2 is arranged around the material hole 1 because it is necessary to irradiate the solidified surface where the mixed material of metal aluminum and iron oxide collides with the flame of the fuel gas.

In FIG. 1, which is an external view of a converter furnace at the time of removing solidified material (metal, slag) from the furnace mouth, the solidified material 8 uses a refractory lining inside the furnace and a steel shell outside the furnace as a base material. . Solidification 8
, The propane and oxygen premixed were injected from the fuel gas injection hole 2 to ignite at the temperature of the solidified material 8.

The surface temperature at the start of the removal of the solidified material 8 reached a temperature (about 1200 ° C.) at which the mixed material of metallic aluminum and iron oxide ignited about 10 seconds after burning the fuel gas. At this point, a mixed material of metal aluminum and iron oxide is sprayed, and the solidified material is melted at the same time as the molten material, and the removal starts. Here, the flame of the fuel gas is maintained such that the surface temperature of the solidified material 8 becomes equal to or higher than the ignition temperature of the mixed material of metallic aluminum and iron oxide. Since the combustion temperature of the mixed material of metal aluminum and iron oxide is sufficiently high with respect to the melting point of the solidified material, the viscosity of the generated molten material is low.

As described above, the removal can be continued by repeating the generation of the melt, the flow of the melt, and the exposure of the solidified surface, and the removal is performed along the moving direction by moving the removing device 6 during the removal. Here, the numerical values of the fuel gas amount, the distance L, the particle size of the metal aluminum and the iron oxide, and the mixing ratio of the metal aluminum were the same as the condition 12 in Table 1. However, the distance L fluctuated in the range of 600 to 1000 mm due to irregularities on the surface of the solidified material.

The conventional method of injecting oxygen from an iron pipe and injecting oxygen together with fuel gas and iron powder, the result of removing solidified material adhering to the extent that the raw material charging container cannot be inserted over the entire periphery of the converter furnace opening, and injecting oxygen together with fuel gas and iron powder The results are shown in Table 3 in comparison with the conventional method 2.

The solidified material in which the slag and the ingot were mixed adhered with an average thickness of 1000 mm over the entire circumference of the converter furnace port. In the present invention, it was possible to remove the solidified material having a thickness of 100 mm over the entire circumference of the furnace port in the time between operations (20 minutes). On the other hand, in the conventional methods 1 and 2, it took three times as long as the present invention, but only 1/3 or 2/3 of the entire circumference of the furnace opening could be removed.
Moreover, the thickness of the solid matter that could not be removed is １ ／ of that before removal.
In many cases, the operation must be removed again after the next operation, which significantly reduces the operation efficiency.

[0032]

[Table 3]

FIG. 4 shows a sectional view (a) and a front view (b) of a removing apparatus according to a second embodiment for carrying out the method of the present invention. In FIG. 4, a removing device 7 for injecting a gas together with a mixed material of metallic aluminum and iron oxide and a fuel gas arranges a material hole 1 for injecting a mixed material of metallic aluminum and iron oxide in the center,
A plurality of fuel gas injection holes 2 are provided around the material hole 1 in multiple stages on a concentric circle of the material hole 1, and a plurality of gas injection holes 3 are provided between the material hole 1 and the innermost fuel gas injection hole 2. The gas injection holes 3 are provided so that the injection direction 4 of the gas injection holes 3 is directed to the injection direction 5 of the material holes 1.

The material hole 1 is arranged at the center of the removing device 7 in order to cause the mixed material of metallic aluminum and iron oxide to concentrate and collide with the solidified material surface by the carrier gas. The gas injection holes 3 are disposed between the material holes 1 and the fuel gas injection holes 2 because the melt produced by burning a mixed material of metallic aluminum and iron oxide at the time of collision with the solidified material is hindered by the melt flow and continues. When it is not possible to remove the melted gas, it is arranged to scatter the retained melt. Even if it is arranged on the outer periphery of the fuel gas injection hole 2, the gas injected from the gas injection hole 3 is separated by the flame of the fuel gas. Therefore, the scattering efficiency of the staying molten material is deteriorated.

The reason why the injection direction 4 of each gas injection hole 3 is directed to the injection direction 5 of the material hole 1 is to concentrate the gas injected from the gas injection holes 3 on the retained molten material. . The fuel gas injection hole 2 irradiates the solid material surface where the mixed material of metallic aluminum and iron oxide collides with the flame of the fuel gas, and the scattering of the molten material retaining the gas injected from the gas injection hole 3. In order to perform the process efficiently, they are arranged on the outer periphery of the material hole 1 and the gas injection hole 3.

In FIG. 2, which is an external view of the ladle furnace opening when solidified materials (metal and slag) are removed, the solidified material 11 uses a refractory lining inside the furnace as an adhesion base material. The removing device 7 was held at a position of a distance M with respect to the solidified material 11, and propane and oxygen mixed in advance were injected from the fuel gas injection holes 2 to ignite with an ignition torch using coke oven gas as fuel.

The surface temperature at the start of the removal of the solidified material 11 reached a temperature (about 1200 ° C.) at which the mixed material of metallic aluminum and iron oxide ignited about 12 seconds after the combustion of the fuel gas. At this point, a mixed material of metal aluminum and iron oxide is sprayed, and the solidified material is melted at the same time as the molten material, and the removal starts. Here, the flame of the fuel gas is maintained such that the surface temperature of the solidified material 11 becomes equal to or higher than the ignition temperature of the mixed material of metallic aluminum and iron oxide. Since the combustion temperature of the mixed material of metal aluminum and iron oxide is sufficiently high with respect to the melting point of the solidified material, the viscosity of the generated molten material is low.

As described above, the removal can be continued by repeating the generation of the melt, the flow of the melt, and the exposure of the surface of the solidified material, and the removal is performed along the moving direction by moving the removing device 7 during the removal. However, the position where the solidified material is attached (for example, in a horizontal state), the shape of the solidified material in the removed portion (for example, the removed portion is concave with respect to the surroundings), the amount of melt produced (the melting point of the solidified material is low and the melt flow rate is restricted), etc. This may cause the melt to stay in the removal section. In this case, a gas is injected from the gas injection holes 3 to scatter the melt. When the melt no longer stays, the injection gas is stopped, and when the melt stays again, the gas is injected. In this manner, gas injection and stop are performed based on the stagnation state of the melt, and the gas injection is controlled so that the melt does not stagnate in the removing unit.

Here, the values of the fuel gas amount, the distance M, the particle size of the metal aluminum and iron oxide, the mixing ratio of the metal aluminum, and the gas injection speed were the same as the conditions 30 in Table 2. But,
The distance M is 400 to 700 m because the surface of the solidified material has irregularities.
m. In addition, the gas injection speed was controlled by the flow rate of the oxygen gas so that the gas flow rate was 100 to 140 m / sec based on the retention state of the melt, and the injection and stop of the gas were also controlled.

A conventional method of injecting oxygen from an iron pipe using the result of removing solidified material adhering to the extent that a degassing facility cannot be installed over the entire circumference of the ladle furnace mouth, and injecting oxygen together with fuel gas and iron powder Table 4 shows a comparison with the conventional method 2. The solidified material in which the slag and the ingot were mixed was attached with an average thickness of 500 mm over the entire circumference of the ladle opening. In the present invention, it was possible to remove the solidified material having a thickness of 50 mm over the entire circumference of the furnace port in a time allowed for operation (20 minutes). On the other hand, in the conventional methods 1 and 2, it took about three times as long as that of the present invention, but only 1/4 or 1/3 of the entire circumference of the furnace opening could be removed. Since the operation was not possible due to the large 3/5 before the removal, the machine was removed by a dismantling machine in preparation for damage to the refractory lining. In this way, removal by the demolition machine and repair of the damaged part of the refractory lining significantly hindered the operation.

[0041]

[Table 4]

[0042]

According to the present invention, the solidified material can be melted and removed at a high speed and at a stable removal rate without being affected by the temperature, the adhesion state, and the suspended state of the solidified material. In Table 3 of the results, almost the entire amount of solidified material could be removed in one-third the removal time compared to the conventional method. In addition, in Table 4 of the solidified matter removal results of the second example, almost the entire amount of solidified matter could be removed in less than 1/3 of the conventional method. Since the solidified material can be removed in such a short time, there was no influence on the operation.

Further, the method of the present invention can be used for melting and removing solidified slag floating on the surface of a molten metal contained in a molten metal container such as a ladle. The probe can be quickly immersed in the molten metal without the need for slag splitting. Further, at this time, an excellent effect of preventing solidification of the molten slag and adding a heat insulating material to enable several times of probe immersion can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of a converter furnace opening according to a first embodiment of the present invention when solidified material is removed.

FIG. 2 is a view showing an appearance of a ladle furnace opening according to a second embodiment of the present invention when solidified material is removed.

FIG. 3 is a diagram showing a removing apparatus used for removing solidified material from a converter furnace mouth according to a first embodiment of the present invention, wherein (a) is a sectional view,
(B) is a front view.

FIG. 4 is a view showing a removing device used for removing solidified material from a ladle furnace opening according to a second embodiment of the present invention, wherein (a) is a sectional view,
(B) is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material hole 2 Fuel gas injection hole 3 Gas injection hole 4 Injection direction of gas injection hole 5 Injection direction of material hole 6, 7 Removal device 8, 11 Solidified material L, M Distance between removal device and solidified material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F27D 3/15 F27D 23/02 C21C 5/46 104 C10B 43/10

Claims (2)

(57) [Claims] 1. A method of disposing solid material such as metal, slag, etc. by disposing a material hole in the center and surrounding a plurality of fuel gas injection holes around the concentric circle of the material hole in multiple stages. The fuel gas is injected from the fuel gas injection hole, and the metal aluminum having a particle size of 0.15 mm or less 15 to 60 wt.
%, And a solid material such as ingots and slag is melted and removed by injecting a mixed material composed of iron oxide having a particle size of 0.4 mm or less with the balance being 0.4 mm or less. 2. A material hole is disposed at the center, a plurality of fuel gas injection holes are provided around the material hole in multiple stages on a concentric circle of the material hole, and a plurality of fuel gas injection holes are provided between the material hole and the innermost fuel gas injection hole. In the method of melting and removing solidified material such as ingots and slag by surrounding gas injection holes, a fuel gas is injected from the fuel gas injection holes, and a metal aluminum 15 having a particle size of 0.15 mm or less is formed from the material holes.
A mixed material consisting of iron oxide having a particle size of 0.4 mm or less and a balance of not more than 60 wt% is injected, and the solidified material surface is removed so that the gas flow rate from the gas injection hole to the gas injection hole outlet is 100 m / sec or more. A method for melting and removing solidified materials such as ingots and slag by injecting into a part to melt and remove solidified materials such as ingots and slag.