JPH04304305A - Method for charging raw material in blase furnace - Google Patents

Abstract

PURPOSE:To improve ventilation and efficiency by charging the raw material of coarse grain into the center part of a furnace in a horizontal and flat state in a vertical two-stage hopper type bell-less blase furnace. CONSTITUTION:The raw materials are successively charged from coarse grain to fine grain into the furnace 11 from the center part of the furnace to outer peripheral part from a lower hopper 6 in two-stage hoppers through a swinging chute 10, and by charging these in the horizontal and flat state, the ventilation is improved. The ventilation and the stabilization of furnace are improved, thereby saving a fuel cost.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method of charging metallurgical raw materials, etc. to a bell-less blast furnace, by making the stacking angle of the metallurgical raw materials horizontal and flat, the coke mixing ratio distribution and particle size distribution in the radial direction. The present invention relates to a technology for forming a charge layer with excellent air permeability by stably and accurately controlling

0002

[Prior Art] In order to operate a blast furnace stably, it is necessary to precisely control the distribution of the charge at the top of the blast furnace. Metallurgical raw materials, etc. are introduced along the trajectory of

0003

[Problems to be Solved by the Invention] However, even with the above-described method, it is not possible to avoid the phenomenon in which coarse particles gather around the outer periphery of the top hopper, which is peculiar to the use of a bellless type blast furnace top charging device. This invention was made in view of the above circumstances, and an object of the present invention is to provide a technology for forming a layer of metallurgical raw materials charged in a furnace in which coarse grains gather in the center to form a charge layer with excellent air permeability. With the goal.

0004

[Means for Solving the Problems] A method for charging raw materials into a blast furnace according to the present invention is a method for charging metallurgical raw materials and coke raw materials using a vertical two-stage hopper type bellless type blast furnace furnace top charging device. It is characterized by charging the raw material along a spiral trajectory from the center to the outer periphery, with coarse grains in the center and fine grains in the outer periphery. Furthermore, the method is characterized in that the raw material is charged so that the upper surface of the charge deposited in the blast furnace is horizontal and flat.

[0005]

[Operation] When using the vertical two-stage hopper type bellless blast furnace top charging device, the particle size of the falling coke and iron ore is the largest at the beginning when the port is opened and gradually becomes smaller.
According to the charging method of the present invention, the central part of the charge is formed of coarse grains and the outer peripheral part is formed of fine grains, so that a charge layer with excellent air permeability etc. is formed. In the case of a vertical two-stage hopper type bell-less blast furnace top charging device, coke 9 falls from the lower hopper 6 to the rotating chute 10 through the port 8.
It was also found that the particle size of iron ore 4 was largest at the beginning when port 8 was opened and gradually became smaller. This situation is shown in Figure 2. The horizontal axis shows the time elapsed since port 8 was opened and the introduction of coke 9 and iron ore 4 was started. The vertical axis displays values with the average particle size as the denominator and the particle size at each period as the numerator. As can be seen from Figure 2, the particle size at the initial stage when port 8 is opened is about 1.5 times the average particle size, and the particle size gradually decreases to about 1 minute and 15 seconds after port 8 is opened. It becomes .0 times, and becomes about 0.9 times after 2 minutes and seconds.

Based on the above conditions, according to the method of the present invention in which metallurgical raw materials are charged along a spiral trajectory from the center to the outer periphery, the center of the charge is formed of coarse grains and the outer periphery is formed of coarse grains. Since it is formed of fine particles, it forms a charge layer with excellent air permeability.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a blast furnace top charging device used in the present invention. The blast furnace top charging device used in this example is of a vertical two-stage hopper type and has an upper hopper 3 and a lower hopper 6. Iron ore is passed through a charging chute 2 and charged into an upper hopper 3 by a charging conveyor 1. In the figure, 4 is iron ore charged into the upper hopper 3. The upper hopper 3 has four ports 5 at the bottom. It is always hermetically closed. A lower hopper 6 is provided below it. In the figure, 7 is coke that is introduced into the lower hopper 6 from the port 5. The lower hopper 6 has one port 8 at its bottom. Lower hopper 6
The coke 7 stored in the tube passes through the port 8 and falls into the rotating chute 10. The rotating chute 10 injects coke 9 along a spiral trajectory from the center toward the outer periphery to form a layer of coke 9. The layer of coke 9 is initially formed in a circular shape with a small diameter in the center, and as the rotating chute 10 gradually increases the inclination angle and moves the falling position of the coke 9 to the outer periphery, the layer of coke 9 is formed in the center. Expanding in diameter, the layer of coke 9 eventually reaches the blast furnace wall. In the figure, 11 is the furnace body of the blast furnace.

[0008] In this case, the raw material dropped from the rotating chute 10 is directly dropped at the target position to be deposited, and does not roll on the surface of the charge deposited in the furnace. Here, the opening degree of the port 8 was adjusted so that the thickness of the charge layer was uniform, and the surface of the deposited charge was made horizontal and flat.

FIG. 4 shows the situation inside the blast furnace according to the method of charging metallurgical raw materials, etc., in a blast furnace according to the present invention, in which the upper surface of the accumulated charges in the blast furnace is horizontal and flat. showed that. According to this method, it is possible to charge metallurgical raw materials thickly in the outer peripheral part, and charge large lumps of coke in the center and small lumps of coke in the outer periphery. In addition, the metallurgical raw materials, etc., are introduced so that the upper surface of the accumulated charges in the blast furnace is horizontal and flat, so the accumulated charges form a mountain and the metallurgical raw materials, etc., introduced into the blast furnace are transferred. Since there is no movement, the desired charge distribution is maintained stably,
The formed charge layer with excellent air permeability etc. will stand.

On the other hand, FIG. 3 shows a case in which a conventional method of adding metallurgical raw materials and the like is used. According to the conventional method of charging metallurgical raw materials, etc., the charges accumulated near the outer periphery form a mountain and the loaded metallurgical raw materials, etc. roll on top of it, so that iron ore and coke are rolled in the center. A mixed layer occurs and the desired charge distribution cannot be obtained.

[0011] The wind pressure loss/air volume in the standard state is usually called the K value, and in FIG. 5, the K value at the lower part of the furnace body is displayed on the vertical axis. The horizontal axis of FIG. 5 shows the strength of coke after hot reaction. As can be seen from FIG. 5, it was found that the charging method of the present invention formed a charge layer with far superior air permeability, etc., compared to the conventional charging method.

FIG. 6 shows the carbon solution loss of coke carbon on the vertical axis. The horizontal axis of FIG. 6 shows the strength of coke after hot reaction. As can be seen from FIG. 6, it was found that the charging method of the present invention formed a charge layer with far superior reducing properties, air permeability, etc., compared to the conventional charging method.

The blast furnace in which this example was carried out had an internal volume of 40
50M3, and when using the conventional charging method, the amount of pig iron tapped was 10,000 T/day, but according to the charging method of the present invention, the amount of pig iron tapped was 10,500 T/day, which was significantly improved.

[0014]

[Effect of the invention] When metallurgical raw materials, etc. are charged by the method of the present invention in a vertical two-stage hopper type bellless blast furnace,
By charging coarse-grained metallurgical raw materials into the center of the furnace, the air permeability inside the furnace is equalized and the conditions of the blast furnace are stabilized, resulting in an increase in the tap iron ratio, a decrease in the coke ratio, and a decrease in Si in the hot metal. will be realized.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a blast furnace top charging device used in the present invention.

FIG. 2 is a graph showing the relationship between the time from the start of charging metallurgical raw materials and the like from the lower hopper of the vertical two-stage hopper bell-less blast furnace top charging device and the particle size at each period.

FIG. 3 is an explanatory diagram showing the state of the charge in the furnace when a conventional method of charging metallurgical raw materials, etc. is used.

FIG. 4 is an explanatory diagram showing the state of the charge in the furnace when using the method of charging metallurgical raw materials and the like according to the embodiment of the present invention.

FIG. 5 is a graph showing the wind pressure loss/air volume (K value) and the strength of coke after hot reaction in the case of the present invention and the case of the conventional method.

FIG. 6 is a graph showing the carbon solution loss of coke and the strength of coke after hot reaction, comparing the case of the present invention and the case of a conventional method.

[Explanation of symbols] 1 Charging conveyor 2 Charging chute 3 Upper hopper 4 Iron ore 5 Port 6 Lower hopper 7 Coke 8 Port 9 Coke 10　Turning chute 11 Furnace body

Claims (2)

[Claims] Claim 1: A method of sequentially charging metallurgical raw materials and coke raw materials using a vertical two-stage hopper type bellless blast furnace top charging device, in which metallurgical raw materials and coke raw materials are sequentially charged along a spiral trajectory from the center toward the outer periphery. A method for charging raw materials into a blast furnace, which is characterized by charging raw materials, and charging coarse grains at the center and fine grains at the outer periphery. 2. The method according to claim 1, wherein the raw material is dropped horizontally and flatly onto the upper surface of the charge deposited in the blast furnace, and the raw material is directly dropped into the raw material deposition position without rolling. How to charge raw materials into a blast furnace.