JP2562768B2 - Melting method of molten metal container - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fusing a molten metal container, for example, a metal ingot attached to a furnace opening portion of a converter, a pig iron wheel or the like.

[0002]

2. Description of the Related Art Conventionally, a molten metal container, for example, a molten metal is deposited as a bare metal by spitting / sloping during refining in a converter or a part of the molten metal is deposited as a bare metal on a furnace opening during tapping. Such a metal not only deteriorates the gas recovery rate for preventing the gas recovery skirt from descending, but also falls and drops during the repair of the converter, which is very dangerous. Therefore, to remove the metal that adheres to the converter mouth, an oxygen lance for blowing is used, and a horizontal injection horizontal nozzle is attached to the tip of the lance to inject oxygen horizontally to remove the metal. It has come.

However, in this method, since the direction of the oxygen blowout extends over the entire surface of the horizontal nozzle, bricks without metal deposits are melted and the life of the furnace is shortened.
As in Japanese Patent No. 42433, oxygen is ejected radially from an outer jacket attached to the tip of a blowing lance to blow out oxygen in a radial direction in accordance with the adhesion state of the metal when melting the metal at the furnace mouth portion. That is, it is possible to easily change the direction and the direction, prevent the brick from being melted in a portion where the metal is not adhered, and efficiently cut the metal. In addition, JP-A-64-
Actually, as in Japanese Patent No. 75620, a method of removing the metal by colliding high pressure water together with a high temperature flame from an injection nozzle against the metal adhered to the converter or a manual fusing work using an oxygen pipe is the actual situation.

[0004]

As described above, as in the conventional method of Japanese Utility Model Laid-Open No. 58-42433, oxygen is spouted radially from the outer jacket attached to the tip of the blowing lance, In the method of fusing the ingot of the furnace mouth portion, the fusing is performed regardless of the amount (thickness) of the ingot, so that not only the efficiency is poor, but also the converter iron shell and the brick may be damaged. Further, in JP-A-64-75620, since water is used, there is a high risk of steam explosion, and the cooling effect of water causes a rapid drop in the temperature inside the converter furnace, which impedes operation. Come on. On the other hand, in the case of manual work, there are problems such as not only low efficiency due to manual work but also danger due to work near the converter.

[0005]

[Means for Solving the Problems] As a result of the inventors' earnest efforts to solve the above-mentioned problems, as a result of changing the burner flame capacity according to the thickness of the metal, the effect on the refractory material is affected. The purpose is to prevent melting loss by minimizing the above. The gist of the invention is that, in a method of fusing a metal adhered to a molten metal container with a burner flame, a powder-added oxygen fusing burner is used to perform high-speed fusing of extremely thick metal by primary powder fusing, Next, there is provided a method of fusing a metal adhered to a molten metal container, which comprises performing a secondary gas fusing and then performing a stepwise fusing by sequentially switching a burner changeover to a third finish fusing using only oxygen.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a side view showing a situation in which the metal is attached to the top of the converter. As described above, in the molten metal container, not only the generation of adhered metal due to spitting and sloping during refining or simply metal, but also slag and metal are mixed or alternately grown to form a layer. Fig. 1 shows the situation of these metal deposits. That is, the adhered metal 2 is firmly adhered to the furnace top portion of the converter furnace body 1, particularly to the furnace mouth. It is necessary to peel and dismantle the strongly adhered metal layer efficiently without damaging the furnace brick.

FIG. 2 is a schematic view showing a step of melting metal deposits on the furnace top according to the present invention. The burner flame is the most widely used method for melting the metal, but generally the burner cutting ability and the risk of melting damage such as refractory are contradictory, and by increasing the burner cutting ability, Although the speed can be increased, the risk of melting of refractory materials is increasing. Therefore, in the present invention, the ability of the flame is changed according to the thickness of the metal to minimize the influence on the refractory material and avoid the melting loss. In other words, as the remaining thickness of the metal becomes smaller, the fusing capacity of the burner is switched to gradually lower the capacity, and if the burner flame hits the refractory material, it will not melt the refractory material. It removes the metal.

[0008]

As an embodiment of the present invention, therefore, as shown in FIG. 2, the furnace mouth of the refractory 4 spread inside the furnace of the iron shell 3 which is the frame of the furnace body forming the furnace top of the converter is attached. In removing the base metal 2, a powder melting method capable of high-speed cutting of a portion corresponding to the (A) part of the adhered base metal 2 as a first step using the powder-added oxygen fusing burner 5 according to the present invention. At the start of melting. Reference numeral 6 indicates a melting direction of the powder-added type oxygen melting burner 5. FIG. 3 is a flowchart showing a method for changing the burner flame capacity according to the present invention. As shown in FIG. 3, an oxygen jet is added with LPG for preheating the metal and pure iron powder for improving the heating effect, so that the extremely thick metal can be fused at high speed. The (A) portion of the metal is melted by this first melting of the powder. Next, after reaching the part (A), the iron powder is gradually reduced and the secondary gas is melted.

That is, since the cutting ability decreases with the decrease of the iron powder, the cutting speed is reduced according to the decrease of the iron powder, and thereafter the fusing is performed only by the secondary gas fusing. Finally, when the thickness of the metal reaches the point (B), the preheating by LPG is interrupted, and the secondary oxygen fusing is started, and the metal in the form of a thin film is completely removed from only oxygen. By such a fusing method, a flame having a high-speed fusing ability does not directly contact the refractory, and in the cutting of the metal in the vicinity of the refractory, it is possible to prevent melting damage of the refractory or the like by the low-performance flame.

FIG. 4 is a sectional view of the tip of a powder-added type oxygen fusing burner for carrying out the present invention. A cutting oxygen port 8 is provided in the center of the tip of the burner body 7, a preheating LPG gas outlet 9 is provided on the outer periphery of the cutting oxygen port 8, and a preheating oxygen port 10 is further provided on the outer periphery, and the outer periphery is provided from the center. A fusing burner having a structure in which an iron powder outlet 11 and an addition LPG gas outlet 12 are provided on the surface is used. This fusing burner is attached to the tip of a movable arm (not shown), and for example, it is possible to adopt a structure in which it can be mounted on a moving carriage and sprayed from all directions of up, down, left and right. In addition, since the metal removal work is dangerous, it is possible to remotely operate the operation panel, iron powder is connected to the fusing burner with a nitrogen carrier for iron powder supply, and oxygen is used for cutting oxygen and preheating oxygen. The LPG fuel gas is supplied from the oxygen cylinder and from the LPG cylinder, respectively, and the pipes are switchable. Furthermore, the thickness of the metal is detected by a magnetic sensor (not shown), and control is possible to prevent damage to sound refractories.

[0011]

[Examples] In removing the bare metal adhering to the converter mouth, the three-stage fusing shown in FIG. 3 was performed using the powder-added type oxygen fusing burner shown in FIG. That is, as a powder-added type oxygen fusing burner, oxygen, Max 730 Nm ³ / h (cutting oxygen 700 Nm ³ / h, preheating oxygen 30 Nm ³ / h), L
PG40Nm ³ / h (preheated LPG20Nm ³ / h, added LPG20Nm ³ / h) and iron powder Max 2kg / mi
Using a fusing burner of n (nitrogen transfer 20 Nm ³ / h), the cutting was started by the fusing of the first powder, and 2000 mm
The above extremely thick metal can be cut at a high speed of 100 mm / min or more, and the metal is melted to the remaining thickness of about 100 mm. Next, the iron powder is reduced to the secondary gas melting and the iron powder is reduced. Cutting ability is lowered, cutting speed is reduced according to the decrease of iron powder, iron powder supply amount 0kg / mi
n at a speed of about 50 mm / min, then oxygen and L
Fusing of only PG was performed. Finally, when the thickness of the base metal reached about 50 mm, the preheating by LPG was interrupted, and the process proceeded to the third oxygen fusing, and the base metal in the form of a thin film was completely removed by only oxygen. As a result, the flame of high speed cutting force due to the fusing of the first powder does not directly contact the refractory,
In addition, when cutting metal in the vicinity of refractory
Since the secondary oxygen fusing was used, the melting damage to the refractory could be completely prevented.

[0012]

As described above, according to the present invention, the metal adhered to the top of the furnace such as a converter can be removed at high speed without damaging the refractory. Not only is it possible to save a huge amount of labor, but it is also effective for extending the life of converters, etc. Moreover, automation is easily possible, and various excellent effects that conventional dangerous work can be done safely Is played.

[Brief description of drawings]

FIG. 1 is a side view showing a situation where metal is attached to the top of a converter.

FIG. 2 is a schematic view showing a step of melting metal deposits on the furnace top according to the present invention.

FIG. 3 is a flowchart showing a method for changing the burner flame capacity according to the present invention.

FIG. 4 is a cross-sectional view of the tip of a powder-added type oxygen fusing burner for carrying out the present invention.

[Explanation of symbols]

 1 Furnace body 2 Furnace deposit metallurgy 3 Iron skin 4 Refractory 5 Powder-added type oxygen fusing burner 6 Burner fusing direction 7 Burner body 8 Cutting oxygen port 9 Preheating LPG gas outlet 10 Preheating oxygen port 11 Iron powder outlet 12 For addition LPG gas outlet

Claims (1)

(57) [Claims] 1. A method for fusing a metal adhered to a molten metal container with a burner flame, in which a powder-added oxygen fusing burner is used to perform high-speed fusing of extremely thick metal by fusing the first powder and then the second A method for fusing a metal adhered to a molten metal container, characterized in that after the gas fusing, the third finishing fusing by oxygen only is successively performed by stepwise fusing by switching the burners.