JPH06257947A - Method and device for stopping melt discharge port - Google Patents

Abstract

PURPOSE:To minimize generation of bridge to realize a smooth discharge of metal, by a method wherein heat resisting powdery grains covered with grains whose main component is carbon are transferred by gas, jetted out through a discharge nozzle which is inserted into a melt discharge port, and heaped on an upper surface of an opening and closing lid for stopping the discharge port. CONSTITUTION:In a blast furnace or a refining furnace, a melt discharge port 2 which is opened at a bottom part is stopped by an opening and closing lid 8, which is driven to open and close by a cylinder through a link 10. A discharge nozzle 11 passing through the opening and closing lid 8 and having a stopper 11A at a tip end is inserted into the melt discharge port 2. Heat resisting powdery grains 5 transferred by gas through a transfer passage 7 are jetted from the tip end of the discharge nozzle 11 to collide against the stopper 11A, so that they may be heaped on an upper surface of the opening and closing lid 8 and stop the discharge port 2. On the other hand, following an opening or a closing of the opening and closing lid 8, the heaped powdery grains 5 are made to drop down so as to open the discharge port 2. At this time, the heat resisting powdery grains 5 are covered with grains whose main component is carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant powder powder for closing a molten metal discharge port provided at or near a furnace bottom of a melting furnace such as a converter, an electric furnace, a smelting reduction furnace, or a smelting furnace. It relates to a filling and a closure method.

[0002]

2. Description of the Related Art In a conventional melting furnace such as a converter, an electric furnace or a smelting reduction furnace or a refining furnace, molten metal (molten steel,
Molten metal such as hot metal or slag) is provided with an outlet, and the furnace body is tilted for tapping. In this tapping method, there is no molten metal discharge port in the furnace bottom, so there is no leakage of molten metal from the furnace bottom during melting or refining, and there is an advantage that the molten metal discharge port does not need to be blocked or opened. is there.

However, it is necessary to install a furnace body tilting device for tilting the furnace body, which increases equipment costs. Also, when the furnace body is tilted, the molten metal comes into contact with the furnace wall bricks and the molten metal temperature drops,
It causes melting of the upper brick of the furnace. Furthermore, in the furnace when tapping,
In continuous operation in which coke, undissolved, and unreduced solid charge remains inevitably, tilting of the furnace body is often undesirable.

On the other hand, in the case of a furnace having a molten metal discharge port at or near the bottom of the furnace wall, it is not necessary to tilt the furnace when discharging the molten metal, but the discharge port is blocked during melting and refining operations. It is necessary to open this when tapping hot water. The applicant has closed the molten metal discharge port provided at the bottom of such a furnace,
The inventor has devised a method and apparatus for efficiently performing the opening operation (see Japanese Patent Laid-Open No. 2-277710). FIG. 1 is a diagram showing a method for closing and opening the molten metal discharge port and an apparatus used for the method.

As shown in FIG. 1, a refining furnace or a melting furnace 1
Has a molten metal outlet 2 at the bottom. The molten metal discharge port 2 is closed by an opening / closing lid 8 and can be opened / closed via a link 10 by the withdrawal / retraction of the rod of the cylinder device 9. Reference numeral 3 is a hole for maintenance of the discharge port.

FIG. 2 is an enlarged sectional view of the vicinity of the molten metal discharge port of FIG. As shown in the drawing, a discharge nozzle 11 having a stopper 11A at the tip is inserted into the discharge port through the opening / closing lid 8. Heat-resistant powder 5 which is gas-transported from the tank 4 via the transportation path 7 by the gas from the compressed air source 6 shown in FIG.
Is ejected from the tip of the discharge nozzle 11, and the stopper 11A
Then, it is turned downward and is deposited on the opening / closing lid 8 to gradually increase its height.

Above the stopper 11A, the powdery particles 5 form a fluidized bed, but after the air supply is stopped, the powdery material 5 is calmed down and becomes a filling material to block the molten metal discharge port 2.

At the time of tapping, when the opening / closing lid 8 is opened, the discharge nozzle 11 is pulled out integrally with the opening / closing lid 8, so that the filled heat-resistant powder 5 is naturally dropped and the molten metal discharge port 2 is naturally opened. be able to.

As described above, according to the molten metal discharge port closing and opening method and apparatus invented by the present applicant, even if the molten metal discharge port is provided at the bottom of the furnace, the molten metal discharge port can be closed and opened. This can be done mechanically, and manual work can be omitted. Further, since hot water can be discharged without tilting the furnace body, the problems of the conventional tilting hot water discharge method can be solved.

However, for example, in the case of producing pig iron from iron ore or scrap, since the hot metal produced in the furnace has a lower melting point and a lower viscosity than molten steel, the heat-resistant powder granules filled in the hot metal discharge port. It is easy to penetrate into the inside, and so-called bullion is likely to occur. In extreme cases, an abnormal situation may occur in which the hot metal leaks from the bottom of the outlet. When hot metal or molten metal enters the heat-resistant powder or granules, the heat-resistant powder or granules expand or sinter to form a so-called bridge. In such a state, even if the opening / closing lid 8 of FIG. 2 is opened, the filled heat-resistant powdery particles 5 do not drop naturally, resulting in a defective opening of the discharge port.

In case the above natural opening is not possible, if the tip of the discharge nozzle 11 is made to project into the furnace after the filling and closing work is completed, O ₂ gas is supplied from the tip at the time of opening. After melting the sintered filling layer near the discharge nozzle with O ₂ , the opening / closing lid 8 can be opened to open the molten metal discharge port 2. However, if the discharge nozzle 11 is projected into the furnace during the work of melting and refining, clogging and melting loss due to the molten metal will occur, so in order to prevent this, the discharge nozzle 11
In N _2, CO _2, Ar, must flow a cooling gas such as LPG, also task of opening using O ₂ is such damages delays and outlet refractories in the vicinity of the tapping Cause problems.

[0012]

DISCLOSURE OF THE INVENTION An object of the present invention is to form a bridge of heat-resistant powder granules by infiltrating hot metal, slag or the like into the interior of the heat-resistant powder granule filling the molten metal outlet. It is an object of the present invention to provide a filling material that suppresses spillage and enables smooth tapping by a natural opening, and a method for closing a molten metal discharge port using the filling material.

[0013]

The gist of the present invention is the following method (1) for closing the filler and (2) a method for closing the melt outlet.

(1) A filling material for a molten metal discharge port of a melting furnace or a refining furnace, which is composed of a heat-resistant powder material coated with particles containing carbon as a main component.

(2) A melting furnace characterized in that a heat-resistant powdery material coated with particles containing carbon as a main component is transported by gas, ejected from a discharge nozzle inserted in a melt discharge port, deposited and filled. Or the method of closing the molten metal outlet of the refining furnace.

The heat-resistant powder particles (hereinafter referred to as sand particles) constituting the filling material of the molten metal outlet of the present invention include silica sand, olivine sand, magnesia sand obtained by crushing a calcined product of magnesia,
Zircon sand or powder refractory obtained by crushing various bricks can be used.

Examples of particles containing carbon as a main component (hereinafter referred to as C particles) for coating the sand particles include graphite powder, coal powder, coke powder or pitch powder.

There are various methods for coating the surface of the sand particles with C particles, and for example, the following method using an organic or inorganic binder can be adopted.

When using, for example, a resol type phenol resin as the organic binder, the particle size is first set in a kneader.
Knead sand particles of about 1.0 to 2.0 mm and a hardening agent (acid catalyst such as paratoluene sulfonic acid). After uniformly coating the surface of the sand grains with a curing agent, a liquid resol-type phenol resin and C particles having a particle size of 0.01 to 0.1 mm are sequentially added and kneading is repeated, and a curing reaction of the resin proceeds from the sand grain surface side. Next, the curing agent is kneaded again to advance the curing reaction of the resin from the outer surface of the coated resin, thereby coating the C particles on the surface of the sand particles and preventing the sand particles from agglomerating. After that, sieving can be performed to produce sand particles coated with C particles having a predetermined particle size.

When an aqueous sodium silicate solution (hereinafter referred to as water glass) is used as the inorganic binder,
After uniformly coating the surface of sand grains with water glass in a kneader, C
By adding particles and blowing CO ₂ gas during kneading to cure the water glass, it is possible to produce sand particles coated with C particles.

When cement is used as a binder, the surface of the sand grains is uniformly coated with a hardening accelerator such as molasses in a kneading machine, and then cement, water and C particles are added and kneaded again to harden the cement. Sand particles coated with C particles can be produced.

In any of the above-mentioned methods, when the hardening reaction progresses between the sand grains and the agglomeration occurs, the crushed particles collapse in the binder hardening part containing the C particles having low strength and are covered with the C particles. It can be loosened into sand grains.

The operation of the filler of the present invention will be described below together with the description of the method for closing the molten metal outlet of the present invention using the same.

[0024]

As an apparatus for carrying out the method for closing the molten metal discharge port according to the present invention, the above-mentioned JP-A-2-27 shown in FIGS. 1 and 2 is used.
Those disclosed in Japanese Patent No. 7710 can be used.

Since the details of this apparatus have been described above, the description thereof will be omitted.

In the clogging method of the present invention, the above-mentioned C particle-coated sand particles are used as the heat resistant powder particles 5. As described above, the C particle-coated sand particles that have been gas-transported from the tank 4 via the transportation path 7 by the gas from the compressed air source 6 are ejected from the tip of the discharge nozzle 11 to fill the molten metal discharge port 2. is there.

After the molten metal discharge port 2 is closed, melting and refining reactions are performed in the furnace 1 to produce, for example, pig iron, the molten pig iron or slag may infiltrate into the filling material. However, the filling material of the present invention has a poor wettability with hot metal or slag C
It consists of sand grains coated with particles. Therefore, the hot metal or slag does not penetrate deeply. Further, the sand particles coated with the C particles have poor sinterability, and the pressure of the gas generated from the volatile components contained in the C particles causes the sand particles inside the filler and the hot metal or molten slag to come into direct contact with each other to interact with each other. Interfere with. Therefore, sintering does not occur between the sand grains, and the formation of bridges in the filler is suppressed. Therefore, at the time of tapping, when the opening / closing lid 8 is opened and the discharge nozzle 11 and the opening / closing lid 8 are integrally pulled out, the filling material in the molten metal discharge port 2 is naturally dropped and the molten metal discharge port 2 is naturally opened. Thus, the hot metal and molten slag can be discharged smoothly.

In actual operation, an abnormal ingot may suddenly occur, and bridge formation in the packing may be unavoidable. In that case, when O ₂ gas is supplied from the discharge nozzle 11, the filler of the present invention has the C particles coated on the surface of the sand particles, so that the combustion heat of the C particles generated by blowing the O ₂ gas causes the bridge particles to generate heat. The dissolution is promoted and the opening can be performed in a short time. Hereinafter, the effects of the present invention will be specifically described with reference to Examples.

[0029]

EXAMPLE In this example, a converter-type furnace having a molten metal discharge port 2 at the bottom of the furnace as shown in FIGS. 1 and 2 was used. The furnace volume is 10 tons / charge, the melt outlet is 150m in diameter
m, 700 mm in length, the discharge nozzle is a pipe with an inner diameter of 20 mm.

The molten metal discharge port 2 is closed by the opening / closing lid 8, and the tank 4 is closed.
The C-particle-coated heat-resistant powder and granules 5 housed in
Using m ² of N ₂ gas as a carrier gas, it was sent from the discharge nozzle 11 to the inside of the molten metal discharge port 2 at a solid-gas ratio of 1, filled and blocked.

After that, scrap and iron ore were used as iron sources,
After melting and reducing carbonaceous fuel such as coke and coal as an energy source to produce 8 to 10 tons of hot metal having the composition range shown in Table 1, the hot metal discharge port 2 is opened to discharge hot metal and molten slag. The test was repeated. The hot metal temperature is 1400
〜1550 ℃, slag discharge amount in the composition range shown in Table 2 is 0.2〜
It was 4 tons.

[0032]

[Table 1]

[0033]

[Table 2]

The heat-resistant powder has a particle size range of 1.0 to
Silica sand and olivine sand having a composition shown in Table 3 and having a size of 2.0 mm (average particle diameter of 1.5 μm) were used. That is, Example 1 and Comparative Example 1 Silica sand (bulk density: 1.4g / cm ^3), the olivine sand Comparative Example 2 and Example 2 (bulk density: 2.0g / cm ³⁾ was used. In each of Examples 1 and 2, the surface thereof was coated with graphite powder having a particle size range of 0.01 to 0.1 mm and a composition shown in Table 4.
The amount of graphite powder used was 3% by weight of the coated heat resistant powder. A cement binder was used for coating, and the composition was 100 parts of heat-resistant powder, 9 parts of Portland cement in Table 5, 4 parts of water, and 4 parts of molasses as a hardening accelerator.

The coating method is as described above. Comparative Examples 1 and 2 are examples in which the heat resistant powder granules were not coated with graphite powder.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

Table 6 shows the tapping results of Examples and Comparative Examples. The term "natural opening" refers to the state in which the hot metal in the furnace is naturally discharged immediately after the heat-resistant powder in the hot metal outlet drops when the open / close lid of the hot metal outlet is opened. The rate indicates the ratio of the number of times of natural opening to the total number of times of tapping. “O ₂ opening” refers to the case where the forced opening is performed by blowing the O ₂ gas described above.

As shown in Table 6, when the filler of the present invention is used for the molten metal outlet, the number of natural openings is remarkably improved, and the natural opening ratio is changed from 50% in Comparative Example 1 to 90% in Example 1. ,Also,
This was improved from 75% in Comparative Example 2 to 90% in Example 2. Further, even when the bridge formation could not be avoided, the opening work with O ₂ gas was facilitated, and the time required for opening was shortened to half or less in the example as compared with the comparative example.

[0041]

[Table 6]

[0042]

EFFECT OF THE INVENTION By using the molten metal outlet filling material of the present invention, a bridge is formed when molten metal or slag penetrates inside the molten metal outlet filling material provided at the bottom of a melting furnace or a refining furnace. It is suppressed, and smooth tapping can be performed without performing a troublesome opening work with O ₂ gas. Further, even in an abnormal situation in which bridge formation cannot be avoided, opening can be easily performed, and the time required for opening can be shortened, and smooth operation can be achieved.

[Brief description of drawings]

FIG. 1 is a view showing a device for closing and opening a molten metal discharge port used for carrying out the present invention.

FIG. 2 is an enlarged cross-sectional view of the vicinity of the molten metal outlet of FIG.

Claims (2)

[Claims] 1. A filling material for a molten metal discharge port of a melting furnace or a refining furnace, which is made of a heat-resistant powdery material coated with particles containing carbon as a main component. 2. A melting furnace characterized in that a heat-resistant powdery material coated with particles containing carbon as a main component is gas-transported, jetted from a discharge nozzle inserted in a melt discharge port, and deposited and filled. Method for closing molten metal outlet of refining furnace.