JPH0798966B2 - Blast furnace raw material charging method - 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 charging metallurgical raw materials of a bellless blast furnace, and by making the deposition angle of the metallurgical raw materials horizontal and flat, the distribution of coke mixing ratio and the particle size distribution in the radial direction. The present invention relates to a technique for forming a charging material layer having excellent air permeability by stabilizing and accurately controlling the temperature.

[0002]

2. Description of the Related Art In order to operate a blast furnace in a stable manner, it is necessary to accurately control the distribution of the charge at the top of the blast furnace. However, coke, metallurgical raw materials, etc. are swirled from the outer periphery toward the center. Metallurgical raw materials are being injected along the trajectory of.

[0003]

However, even with the above-mentioned method, the phenomenon of gathering coarse particles on the outer peripheral portion of the furnace hopper, which is peculiar to the case of using the bellless type furnace top charging device, cannot be avoided. The present invention has been made in view of such circumstances, and provides a technique for forming a charging material layer excellent in air permeability by gathering coarse particles around a layer of a metallurgical raw material or the like charged in a furnace. With the goal.

[0004]

A method for charging a raw material for a blast furnace according to the present invention is a method for charging a metallurgical raw material using a vertical two-stage hopper type bellless type blast furnace top charging device and a method for charging a coke raw material. It is characterized in that the raw material is charged along a spiral path from the central portion to the outer periphery, and coarse particles are charged in the central portion and fine particles are charged in the outer peripheral portion. In addition to the above method
In the blast furnace, thicken a large amount of coke in the center of the furnace.
Thickly insert the metallurgical raw material into the outer periphery, and
It is characterized by being flat .

[0005]

[Operation] In the case of using the vertical two-stage hopper type bellless type blast furnace top charging device, the grain size of the coke and iron ore falling is the largest at the opening of the port and becomes gradually smaller,
According to the charging method of the present invention, since the central portion of the charging material is formed of coarse particles and the outer peripheral portion is formed of fine particles, a charging material layer excellent in air permeability is formed. Vertical two-stage hopper type Bellless blast furnace top charging device Coke 9 falling from the lower hopper 6 through the port 8 to the swirling chute 10
It was found that the iron ore 4 had the largest grain size at the beginning of opening the port 8 and gradually became smaller. This situation is shown in FIG. The horizontal axis shows the time after the port 8 was opened and the introduction of the coke 9 and the iron ore 4 was started. The vertical axis shows the average particle size as a denominator and the particle size at each time as a numerator. As can be seen from FIG. 2, the particle size at the beginning of opening the port 8 is about 1.5 times the average particle size, and the particle size gradually decreases and after opening the port 8 about 1 minute 15 seconds, the particle size is about 1. It becomes 0.0 times and becomes 0.9 times after 2 minutes and 2 seconds.

From the above conditions, according to the method of charging metallurgical raw material or the like along the spiral path from the central portion to the outer peripheral portion of the present invention, the central portion of the charge is formed of coarse particles and the outer peripheral portion is Since it is formed of fine particles, it is possible to form a charging layer having excellent air permeability.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of a blast furnace top charging device used in the present invention. The blast furnace top charging device used in this embodiment is a vertical two-stage hopper type and has an upper hopper 3 and a lower hopper 6. The iron ore passes through the charging chute 2 and is charged into the upper hopper 3 by the charging conveyor 1. In the figure, 4 is an iron ore charged in the upper hopper 3. The upper hopper 3 has four ports 5 on the bottom. It is always airtightly closed. A lower hopper 6 is provided below it. In the figure, 7 is a coke charged into the lower hopper 6 from the port 5. The lower hopper 6 has one port 8 on its bottom. Lower hopper 6
The coke 7 stored in the vehicle passes through the port 8 and falls on the turning chute 10. The swirling chute 10 throws the coke 9 from the center toward the outer circumference along a spiral trajectory to form a layer of the coke 9. The layer of the coke 9 is initially formed in a circular shape having a small diameter in the central portion, and the turning chute 10 gradually increases the inclination angle, and the layer of the coke 9 is formed as the falling position of the coke 9 moves to the outer peripheral portion. As the diameter increases, the layer of coke 9 eventually reaches the blast furnace wall.
In the figure, 11 is a furnace body of a blast furnace.

Here, the raw material dropped from the swirling chute 10 is directly dropped to the target position for deposition, and does not roll on the surface of the deposited charge in the furnace. Here, the opening of the port 8 was adjusted to make the thickness of the charge layer uniform and the surface of the deposited charge was horizontal and flat.

FIG. 4 shows the situation in the blast furnace according to the method for charging the raw material etc. of the blast furnace in which the metallurgical raw materials are charged so that the upper surface of the deposited charge in the blast furnace of the present invention is horizontal and flat. showed that. According to this method, it is possible to charge the metallurgical raw material to the outer peripheral portion thickly, and to charge the large coke into the central portion and the small coke into the outer peripheral portion. Moreover, since the metallurgical raw materials, etc. are charged so that the upper surface of the deposited charge in the blast furnace is horizontal and flat, the deposited charge forms a pile and the metallurgical raw material, etc. charged above it is transferred. Since it does not move, the desired distribution of the charge is stably maintained as it is, and the formed charge layer having excellent air permeability is relied upon.

Contrary to this, FIG. 3 shows a case of using the conventional method of charging metallurgical raw materials and the like. According to the conventional method of charging metallurgical raw materials, etc., the deposit accumulated near the outer periphery forms a mountain and the metallurgical raw material, etc. charged above it rolls.Therefore, iron ore and coke roll in the center. A mixed layer occurs and the desired distribution of the charge cannot be obtained.

The wind pressure loss / air volume in the standard state is usually called the K value. In FIG. 5, the K value at the lower part of the furnace body is shown on the vertical axis. The horizontal axis of FIG. 5 shows the strength of the coke after the hot reaction. As can be seen from FIG. 5, according to the charging method of the present invention, it was found that a charging layer having far superior air permeability was formed as compared with the case of 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 the coke after the hot reaction. As can be seen from FIG. 6, according to the charging method of the present invention, it was found that a charging material layer having far more excellent reducibility and air permeability was formed as compared with the conventional charging method.

The blast furnace used in this example has an internal volume of 40.
It was 50 M ³ , and the amount of tapping was 10,000 T / day when the conventional charging method was used, but the amount of tapping was 10500 T / day, which was significantly improved by the charging method of the present invention.

[0014]

EFFECTS OF THE INVENTION In a vertical two-stage hopper type bellless blast furnace, when metallurgical raw materials are charged by the method of the present invention,
By loading coarse metallurgical raw materials into the center of the furnace, the air permeability in the furnace is made uniform and the blast furnace furnace condition is stabilized, increasing the tap ratio, lowering the coke ratio, and lowering the Si content in the hot metal. Will be realized.

[Brief description 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 the introduction of metallurgical raw materials and the like from the lower hopper of the vertical two-stage hopper type bellless blast furnace top charging device and the particle size at each time.

FIG. 3 is an explanatory diagram showing a state of a charge in a furnace when a conventional method of charging a metallurgical raw material or the like is used.

FIG. 4 is an explanatory diagram showing a state of a charged material in a furnace when a method of charging a metallurgical raw material or the like according to an embodiment of the present invention is used.

FIG. 5 is a graph showing the wind pressure loss / air volume (K value) and the strength of the coke after hot reaction in comparison between 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 the coke after hot reaction in comparison between the case of the present invention and the case of the 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 swivel chute 11 furnace body

Claims (2)

[Claims] 1. A metallurgical raw material using a vertical two-stage hopper type bellless type blast furnace top charging device and a method of sequentially charging coke raw materials, wherein a spiral path is formed from a central portion toward an outer peripheral portion. A method for charging a raw material for a blast furnace, which comprises charging a raw material, and charging coarse particles in a central portion and fine particles in an outer peripheral portion. 2. A large lump of coke is thickened in the center of the blast furnace.
The method of charging a raw material for a blast furnace according to claim 1 , wherein the metallurgical raw material is thickly charged into the outer peripheral portion so that the upper surface of the charged material is horizontal.