JPH06158139A - Method for preventing fuming at the time of charging molten iron - Google Patents

Abstract

PURPOSE:To prevent fuming and to improve the work in a furnace opening part of a converter by arranging an injection nozzle for inert gas at the outer periphery of a dust collector in the furnace opening part of the converter at the time of charging molten iron into the converter from a ladle and injecting the inert gas at the time just before the pouring, at the intermediate stage of pouring and at the time just before completing the pouring. CONSTITUTION:At the time of charging the molten iron into the converter 2 after conveying the ladle 1 incorporating the molten iron for steelmaking to the furnace opening part of the converter 2, the injection nozzle 4 for the inert gas (nitrogen, etc.) is arranged at the outer periphery of the dust collector 3 in the furnace opening part of the converter so as to be able to form a inert gas curtain 5. In this constitution, at the stage of starting the pouring of molten metal, the inert gas is injected from the vertical direction to the molten iron surface in the ladle 1 just before pouring to surround the molten iron surface with the gas in a short time, and also the pouring is started. Successively, at the intermediate stage of pouring the molten iron, by injecting the inert gas at least one or more times, the pouring of the molten iron is continued, and further, at the stage just before completing the pouring of molten iron, the inert gas is injected. By this method, the generation of the fume at the time of charging the molten iron is prevented and the surrounding equipment is prevented from damaging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of converter work by preventing smoke generation when charging hot metal from a ladle into a converter, and particularly preventing generation of a large amount of smoke at the start, the middle and the end of charging.

[0002]

2. Description of the Related Art Conventionally, countermeasures against smoke and dust have been taken around the converter. In particular, there are exhaust gas treatment equipment and auxiliary dust collection equipment around the converter furnace mouth. Improvements have been made to this sub-dust collection facility with respect to smoke emission when charging raw materials into the converter. However, all the charging was carried by a crane, and the measures against smoke emission of this crane equipment were not sufficient, and it was vulnerable to thermal damage due to high heat smoke generation, and required considerable labor and cost for maintenance. Recently, efforts have been made to improve the work environment around the converter. Typical work steps for producing smoke are when hot metal is transferred from a hot metal car or a hot metal furnace and when hot metal of a ladle is preliminarily adjusted.

In order to prevent smoke generation and improve dust collection when charging hot metal into the converter, the exhaust gas treatment equipment is effectively used to change the rotation pattern of the suction blower to selectively increase rotation during smoke generation. Then, there are a method of sucking with this method, a method of increasing the capacity of the converter furnace dust collector, and sucking. These are used to collect all the generated smoke, and it is difficult to obtain a sufficient dust collection effect even if the equipment is enlarged. In addition, a huge amount of capital investment was required, and there was a cost problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and minimizes capital investment by using an existing converter furnace port dust collector. The purpose is to prevent smoke from being generated when the hot metal in the pot is charged into the converter, protect equipment such as cranes from smoke, and improve the working environment of the converter. That is, as a method of preventing smoke generation during hot metal charging, the use conditions of the nozzle for forming an inert gas curtain were examined, and the most effective method of injecting the inert gas for converter furnace port dust collection was used to determine the hot metal in the ladle. (EN) A method of suppressing the generation of smoke on the surface, and completely introducing the smoke that has been generated into a converter furnace port dust collector and sucking it.

[0005]

SUMMARY OF THE INVENTION The present invention is a method for preventing smoke generation at the time of charging hot metal in a converter furnace for solving the above problems, and the gist thereof is to use a ladle for steelmaking by a ladle. When charging into the converter, a method of forming an inert gas curtain by an inert gas injection nozzle installed on the outer periphery of the converter furnace dust collector to prevent smoke generation. The gas is sprayed from a direction substantially perpendicular to the surface of the ladle, the hot metal surface in the ladle is surrounded by the inert gas in a short time, and at the same time, the pouring is started, and at the intermediate stage of pouring the hot metal. The method for preventing smoke generation during hot metal charging is characterized in that the inert gas is injected at least once or more to continue the injection, and the inert gas is injected immediately before the end of the injection of the hot metal.

That is, when the hot metal is supplied to the converter by a ladle, the smoke generated at the start of charging is efficiently injected by an inert gas for curtain formation immediately before the start of charging. The generated fumes are introduced into the converter furnace port dust collector and sucked. At this time, the timing of injection is important, and the fumes are generated when the surface of the hot metal starts to tilt in the ladle. Therefore, it is necessary to match the timing of the inert gas injection with the timing of the generation. This inert gas injection forms an inert gas curtain between the ladle surface and the injection nozzle, which suppresses smoke generation, and some of the generated smoke is a dust collector at the top of the converter furnace. Will be sucked in and will be completely prevented from leaking to the surroundings.

Further, the angle of the inert gas injection nozzle has a great influence on the generation of smoke. The inventors of the present invention conducted an experiment on the angle of the inert gas nozzle, and examined the angles of inclination of 25 to 30 °, 5 °, and 0 ° with respect to the hot metal surface of the ladle. Was found to have the greatest effect. By the way, it is necessary to continue the supply of hot metal and to perform at least one injection in the middle of the process, and to prevent smoke generation during the hot metal supply by injecting just before the end of the supply. I found out. In this case, the amount of the inert gas injected once is sufficient to fill the entire ladle space in at least a short time, and the amount of injection increases in proportion to the space capacity of the ladle as the supply of hot metal progresses. Need to let.

That is, according to the present invention, most of the fumes are generated by the hot metal that is hot when the hot metal is in contact with air on the ladle surface or during pouring and the hot metal is oxidized. Smoke prevention can only be achieved by sufficiently blocking contact with air with an inert gas. The inert gas used in the present invention may be any industrially usable inert gas such as nitrogen or argon, and nitrogen is generally advantageous in terms of cost.
The present invention will be described in more detail based on examples.

[0009]

FIG. 1 is a schematic view showing an example of a smoke prevention method as an embodiment of the present invention. The ladle 1 is cut by a crane from a hot metal car or a hot metal furnace (not shown in the figure), and the hot metal is cut out and conveyed to the converter furnace mouth. The converter 2 is tilted at a constant angle to prepare the injection for pouring the hot metal. In FIG. 1, the tilting angle of the normal converter is 45 °. An inert gas (nitrogen or the like) nozzle 4 is attached to the outside of the opening of the converter furnace port dust collector 3. Inert gas is ejected from the inert gas nozzle to form the inert gas curtain 5. FIG. 2 is an enlarged sectional view of the inert gas nozzle portion.

As shown in FIG. 2, the nozzle 4 is provided adjacent to the refractory curtain 6 of the converter furnace port dust collector 3 with a pipe 7 for supplying an inert gas. At this time, the number of nozzles 4 may be one or a combination of two or more, and the number may be suitable for the capacity of the ladle. The capacity of the nozzle should be determined to be sufficient to form the inert gas curtain 5 surrounding the surface of the ladle. Next, the nozzle angle in FIG. 2 will be described. The nozzle is installed vertically downward along the refractory curtain at the converter furnace mouth, but the tip of the nozzle has a throat shape with an inclination angle and an outwardly sloping surface with respect to the refractory curtain. Is. In this embodiment, the nozzle inclination angle is 5 ° from the vertical direction, and this angle makes the injection direction of the nozzle and the surface of the hot metal in the ladle substantially perpendicular.

Further, in the present embodiment, the outer opening of the double tube at the tip of the nozzle is provided with a notch on the outside at an inclination angle of 30 °. This is because the formation of the inert gas curtain makes it easier to enclose the entire surface of the ladle by jetting the inert gas for a short time. In the present invention, in the state of FIG. 1, the injection of the inert gas is started immediately before the injection of the molten pig iron into the converter, and the injection of the inert gas is similarly continued during the injection to continue the injection. Then, just before the injection is finished, the smoke is completely prevented by repeating the injection of the inert gas. The present invention is applied at the time of charging the actual converter, and the inert gas is injected immediately before the hot metal injection, and
By injecting an inert gas in the middle stage and the final stage of the injection, the result of repeating a certain number of times shows that the frequency of smoke generation is 1/4 to 1 / in the method of the present invention as compared with the conventional method. It was found that the number was reduced to 3 and was significantly improved.

As described above, according to the present invention, the angle of the inert gas nozzle is made to be perpendicular to the surface of the hot metal, and the timing of the injection of the inert gas is adjusted to charge the hot metal. It was made possible to prevent the scattering of smoke by promoting the generation of smoke or the generated smoke at the converter dust collector.

[0013]

EFFECTS OF THE INVENTION The present invention prevents smoke generation during charging of hot metal into a converter by efficiently enclosing the ladle with an inert gas by forming a curtain of the inert gas,
At the same time, the suction and introduction of smoke into the converter dust collector is promoted to improve the working environment of the converter furnace mouth, which makes it possible to prevent damage to peripheral equipment due to smoke generation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a state of hot metal injection into a converter according to an embodiment of the present invention.

FIG. 2 is an enlarged schematic view of an inert gas nozzle according to an embodiment of the present invention, (a) a front view and (b) a side view.

[Explanation of symbols]

 1 ... Ladle 2 ... Converter 3 ... Converter Furnace Dust Collector 4 ... Inert Gas Nozzle 5 ... Inert Gas Curtain 6 ... Refractory Curtain 7 ... Inert Gas Pipe Piping

Claims (1)

[Claims] 1. A method for preventing fuming by forming an inert gas curtain by an inert gas injection nozzle installed on the outer circumference of a converter furnace dust collector when charging molten steel for steelmaking into a converter by a ladle. Immediately before the start of the hot metal injection, gas is injected from a direction almost perpendicular to the surface of the hot metal in the ladle, and the hot metal surface in the ladle is surrounded by the inert gas in a short time and injection is started at the same time. In addition, the hot metal injection is continued by injecting the inert gas at least once in the intermediate step of the hot metal injection, and the inert gas is injected immediately before the end of the hot metal injection. A method for preventing smoke generation when charging hot metal.