JP3175778B2 - Pretreatment of hot metal in blast furnace cast floor - 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 pretreatment of hot metal in a blast furnace cast bed which can improve the reaction efficiency of a hot metal pretreatment agent sprayed on hot metal in a slanting gutter installed below the tip of a tapping gutter. It is about.

[0002]

2. Description of the Related Art Generally, in a hot metal pretreatment carried out in a blast furnace cast bed, for example, in a desiliconization treatment, as shown in FIG. The falling energy of the hot metal 1 at the installed inclined gutter 3 is used. In order to improve the efficiency of desiliconization, a method has been proposed in which the injection position of the projection lance 5 is changed while being adjusted to the molten metal falling position from the tapping gutter 2.

[0003] In other words, in the desiliconization of molten iron in a casting bed, a method of spraying a desiliconizing agent onto the hot metal and a method of projecting the desiliconizing agent into the molten iron can be distinguished. And because of its high reaction efficiency, it is currently the mainstream technology,
For example, JP-A-61-34111, JP-A-1-119613, JP-A-2-50906, JP-A-60-89260 and JP-A-61-4
No. 3246 discloses a method and an apparatus for projecting a hot metal treating agent from a lance.

[0004] In order to increase the reaction efficiency in these conventional desiliconization techniques, it is necessary to entrain the molten iron into the molten iron with the help of the falling energy when the molten iron falls in addition to the projection from the projection lance. However, in the prior art, automatic control has not been performed including the falling flow position of the hot metal in the tapping process, and this point is solely in accordance with the operation of the projection lance by the operator.

[0005]

As described above, in the prior art, since the molten metal drop position is always judged by human eyes and the lance is moved, there is a problem that individual differences occur in the desiliconization reaction efficiency. When the hot metal does not fall to the center of the inclined gutter, the depth of the hot metal bath is so shallow that the collision force of the desiliconizing agent causes a splash, and there is a problem that the mixing of the desiliconizing agent and the hot metal is not sufficient.

[0006] The present invention solves the above-mentioned problems of the prior art,
An object of the present invention is to provide a method for pretreatment of hot metal in a blast furnace cast bed, which can improve the reaction efficiency of a hot metal pretreatment agent that is projected from a projection lance to a hot metal in a slant gutter by a high-speed airflow.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a hot metal pretreatment agent from a projection lance toward a hot metal surface in a slanting gutter installed below a tip end of a tapping gutter of a blast furnace cast floor. In the method of pre-treating hot metal by projecting the molten iron with a high-speed gas, the inclined pouring gutter can be moved in the width direction with respect to the front end of the tapping gutter, and projected onto a movable lance truck following the movement of the inclined pouring gutter. A lance is mounted, and a dust concentration meter is disposed near the projection lance, and the dust concentration meter is used to measure the dust concentration of the dust-containing gas generated by the hot metal pretreatment in the inclined pouring gutter. And moving the inclined pouring gutter and the lance carriage to a position where the dust concentration is low, and raising and lowering the projection lance.

[0008]

[Action] The amount of hot metal discharged from the taphole of the blast furnace is small in the early stage of tapping, the flow rate increases thereafter, and this increase almost linearly increases until the middle stage. Further, thereafter, fluctuations occur in the relationship between the tap diameter and the furnace internal pressure.
Observation of the position of hot metal falling from the tapping gutter to the slanting gutter due to such fluctuations in tapping volume from the blast furnace reveals that the flow energy is small at the beginning, so the flow energy is small and the hot metal falls relatively short of the tapping gutter end. However, in the middle period when the flow rate of hot metal increases, it flows away and falls due to its flow energy,
The falling position in the width direction of the inclined pouring gutter receiving the hot metal from the end of the tapping gutter fluctuates.

Therefore, according to the present invention, the tilting gutter is moved relative to the tapping gutter in accordance with a change in the molten metal drop position in the width direction of the tilting gutter.
It is a movable type that can be approached and separated, and basically moves the inclined pouring gutter in the width direction so as to guide the falling molten iron to the center in the width direction of the inclined pouring gutter having a large bath depth. Then, the bogie equipped with the projection lance is moved in accordance with the movement of the inclined gutter, and while adjusting the height by raising and lowering the projection lance, the molten iron pretreatment agent is projected by high-speed airflow to pre-process the molten iron in the inclined gutter. I do. The movement position of the inclined pouring gutter and the addition position of the hot metal pretreatment agent combining the movement of the following bogie and the raising / lowering of the projection lance use the indicated value of the dust-containing gas concentration meter arranged near the projection lance. To determine the movement position.

That is, as the reaction of the hot metal pretreatment agent added with a desiliconizing agent or the like proceeds, the amount of generated hot metal pretreatment slag increases, and at the same time, the dust content around the hot metal pretreatment agent addition position decreases. In other words, utilizing the fact that the lower the dust content in the generated gas is, the more efficient the hot metal pretreatment agent is, and moving the inclined gutter and the projection lance to a position where the dust content gas measured by the dust content gas concentration meter becomes lower. I do.

[0011] By doing so, the falling hot metal is received in the central part of the inclined pouring gutter where the bath depth is large,
Splash generation is suppressed, and the hot metal pretreatment agent can be added to a position where the treatment efficiency is good.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. A tilting gutter 3 is supported by a bearing 13 provided on a gutter carriage 15 via a shaft 14. The tilting gutter 3 is tilted by a tilting drive device 11 connected to one shaft 14 on the side opposite to the tapping gutter. It is free. A gutter horizontal moving device 12 (a power cylinder in the drawing) is connected to the side opposite to the tapping gutter of the gutter bogie 15, and the gutter horizontal moving device 12 is operated to move the gutter bogie 15 on the rail 16 to the wheel 17.
The tapping gutter 3 is moved in the width direction by moving the tapping gutter 2 closer to or away from the tapping gutter 2 through the hole.

Above the inclined gutter 3, a lance truck 8 has a rail.
The lance 18 is provided with a support 20, a mount 21 and a rotary driving drum 4 on the lance 8 and a pulley 22 is mounted on the support 20 and the mount 21, respectively. ing. A wire 23 wound around the rotary drive drum 4 is connected to the projection lance 5 via two pulleys 22, and is used to rotate the rotary drive drum 4 forward and reverse.
The projection lance 5 is raised and lowered by winding and rewinding 23.

A lance horizontal moving device 7 (power cylinder in the drawing) is also connected to the lance truck 8 on the side opposite to the tapping gutter, and the lance horizontal moving device 7 is operated to move the inclined pouring gutter 3 as described above. The projection lance 5 is moved in the width direction of the inclined gutter 3 integrally with the lance carriage 8 following the movement. Further, the lance truck 8 is provided with a dust concentration meter 6 near the projection lance 5.

The hot metal 1 discharged from the tap hole of the blast furnace falls through the tapping gutter 2 to the inclined pouring gutter 3. At this time, the drop position of the hot metal 1 is larger at the end of tapping than at the beginning of tapping, so that a large amount of hot metal is discharged because the amount of wear of the taphole refractory is large. Change to 11 side. The desiliconizing agent 9 is supplied from the tip of the projection lance 5 by compressed air onto the hot metal 1 in the inclined gutter 3, and the desiliconized slag 10 generated by the reaction between the desiliconizing agent 9 and the hot metal 1 floats on the hot metal 1. . In order to improve the desiliconization efficiency, it is important that the desiliconizing agent 9 and the hot metal 1 are sufficiently mixed without generating a splash. Therefore, it is required that the depth of the hot metal bath is not reduced. Therefore, it is necessary to always drop the hot metal 1 to the center in the width direction of the tilting gutter 3 using the tilting gutter horizontal moving device 12.

In order for the hot metal 1 falling from the tip end of the tapping gutter 2 to drop to the center of the slanting gutter 3, the indicated value of dust content in the gas generated by the hot metal pretreatment measured by the dust content meter 6 is measured. By operating the gutter horizontal moving device 12 to lower the height, the inclined gutter 3 is moved in the width direction. As a result, the hot metal 1 falls to the center in the width direction of the inclined gutter 3. This is because the more the desiliconization reaction proceeds, the more the generation of the desiliconized slag 10 in the inclined pouring gutter 3 is promoted, and the concentration of dust is reduced.

After the projection lance 5 is moved by the lance horizontal moving device 7 in the same direction by a distance corresponding to the horizontal movement amount of the inclined pouring gutter 3, the optimum point of the desiliconizing agent 9 by the projection lance 5 is further determined. In order to find out, the rotary driving drum 4 is driven so that the indicated value of the
The projection lance 5 is moved up and down via. Fig. 2 shows the dust concentration index and the desiliconization reaction efficiency obtained by indexing the indicated value of the dust concentration meter 6 from 0 to 100, and the tapping Si = 0.40% and the basic unit of the desiliconizing agent = 15kg / tp.
6 is a graph correlated under the conditions of FIG. There is a correlation between the dust content index and the desiliconization reaction efficiency, and it has been proven that lowering the dust content index is effective in increasing the desiliconization reaction efficiency.

In the above embodiment, the case where the hot metal is desiliconized has been described, but the present invention is also applicable to hot metal pretreatment such as dephosphorization.

[0019]

According to the present invention, when determining the position of the desiliconization lance, the dust-containing concentration correlated with the efficiency of the desiliconization reaction is used. Efficiency can be increased. Further, by moving the inclined gutter and the lance device in the horizontal direction, it is possible to perform a desiliconization process that is not affected by a change in the hot metal drop position. Further, according to the present invention, it is sufficiently possible to improve the reaction efficiency by remote control.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention, in which only a tilt gutter is shown in cross section.

FIG. 2 is a graph showing a correlation between a dust concentration index and a desiliconization efficiency.

FIG. 3 is a perspective view showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Hot metal 2 Tapping gutter 3 Inclined gutter 4 Rotary drive drum 5 Projection lance 6 Dust concentration meter 7 Lance horizontal movement device 8 Lance bogie 9 Desiliconizer 10 Desiliconization slag 11 Tilting drive device 12 Gutter horizontal movement device 13 Bearing 14 shaft 15 Gutters 16 Rails 17 Wheels 18 Rails 19 Wheels 20 Posts 21 Mount 22 Pulley 23 Wire

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C21B 7/14 C21C 1 / 04,5 / 46 C21C 7 / 00,7 / 072

Claims (1)

(57) [Claims] 1. A method for pretreating hot metal by projecting a hot metal pretreatment agent with a high-speed gas from a projection lance toward a hot metal surface in a slanting gutter installed below a tip end of a tapping gutter of a blast furnace cast floor, A slanting gutter is movable in the width direction with respect to the front end of the tapping gutter, and a projection lance is mounted on a movable lance truck following the movement of the slanting gutter, and a dust concentration meter is provided near the projection lance. The dust concentration meter measures the dust concentration of the dust-containing gas generated by the hot metal pretreatment in the slant gutter by the dust concentration meter, and the slant gutter and the lance truck are positioned at a position where the obtained dust concentration becomes lower. And moving the projection lance up and down while moving the blast furnace.