JPH08295527A - Method for adjusting component concentration of molten slag for rock wool - Google Patents

Abstract

PURPOSE: To decrease the fluctuations in component concn. as well as to stably adjust component concn. and to flexibly adjust the component concn. at the time of changing the concn. by specifying the component concn. of secondary molten slag and adjusting the flow rate of the gas to be bubbled. CONSTITUTION: A primary electric furnace 8 is arranged upstream and a secondary electric furnace 9 downstream in series. The molten slag 37 is stored in the primary electric furnace 8 and the blast furnace molten slag 36 in a supply ladle 35 is additionally charged thereto and is pooled. The lower parts of plural electrodes 5 inserted into the furnace via a furnace cap 7 are immersed into the molten slag 37 and the temp. is kept constant. A gas bubbling lance 1 is perpendicularly inserted from a lance insertion port 3 disposed in correspondence to the central position of the electrodes 5 and the lower part thereof is immersed into the molten slag 37. The inert gas is blown into the molten slag in the gas bubbling lance 1 and is floated as the blowing air bubbles 11. A component adjusting agent 10 is charged into the furnace from a charge port 4 and the flow rate of the gas to be bubbled is adjusted in such a manner that component concn. C2 of the secondary molten slag 38 tapped from the secondary electric furnace 9 attains the desired component concn. C2.0 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the component concentration of molten slag by using an electric furnace for producing rock wool, using blast furnace molten slag as a main raw material.

[0002]

2. Description of the Related Art Molten slag, which is produced in large quantities during the production of hot metal in a blast furnace, is discharged to a large site to form a solidified slag block, which is then crushed into slag crushed stone, aggregate and roadbed material. Or it was used for landfill. After that, the molten slag by-produced in the blast furnace was rapidly cooled with water to make granulated slag, and it came to be used for blast furnace cement, cement mixture, concrete aggregate, etc.
It has come to be used as a raw material for rock wool used as a heat insulating material and the like.

That is, molten slag produced as a by-product from a blast furnace is charged into an electric furnace, and the component sizing material is charged into the molten slag while heating the molten slag of the main raw material stored in the furnace by electric power from an electrode. , Molten slag for rock wool is manufactured by adjusting the slag component and temperature. In this method, since the high temperature molten slag is heated in the electric furnace, a small amount of energy is sufficient for melting the component adjusting material charged in the molten slag, and thus energy saving is achieved. Generally, molten slag is mainly charged in a batch from the slag charging port provided in the electric furnace, and a predetermined amount of the component controlling material is charged from another component adjusting material charging port, and heated to a predetermined temperature by an electrode. There is.

By the way, it is well known that an inert gas is blown into the molten slag to stir the molten slag by gas bubbling as a means for shortening the time for dissolving the component adjusting material in the molten slag stored in the electric furnace. is there. For example, in Japanese Patent Laid-Open No. 63-69731, a carbonaceous lance for dissolving the component adjusting material is inserted into the electric furnace through a supporting member, pulled out, and attached so as to be vertically movable. It is disclosed to blow into the molten slag in an electric furnace.

Further, in Japanese Patent Laid-Open No. 63-89439, usually, a component adjusting material is charged on the surface of the molten slag from above.
Even in the case of powdery component adjusting materials, the component adjusting materials often do not uniformly dissolve even if an inert gas is blown from the gas bubbling lance into the molten slag and agitates. It is disclosed that a component adjusting material is injected into a molten slag together with an active gas.

Further, in Japanese Patent Application Laid-Open No. 1-111749, a plurality of component adjusting material inlets are installed on the ceiling of the furnace body to separately introduce the component adjusting material, and the introduced component adjusting material is charged with nitrogen gas or the like. It is disclosed that stirring and shortening the dissolution time. Gas bubbling is generally used as a stirring means for accelerating the dissolution of the component adjusting material in the molten slag for rock wool as seen in the above-mentioned prior art, but both are used for the molten slag using one electric furnace. A component additive material is added, and the molten slag is gas bubbled while being heated using an electrode to adjust the target component concentration and temperature. In addition, there is no detailed description of the method for adjusting the component concentration of the molten slag, but in general, the amount of the component adjusting material is added so that the component concentration becomes a desired concentration when the component adjusting material to be added to the electric furnace is almost completely dissolved. However, a method of completely dissolving with a stirrer such as gas bubbling has been adopted, but the component concentration is not stable, and it is difficult to flexibly deal with the change of the component concentration.

Further, in the above prior art, there are two electric furnaces,
In particular, there is no technique for producing rock wool by arranging a primary electric furnace and a secondary electric furnace in series.

[0008]

In the production of rock wool, it is important to adjust the component concentration (mainly SiO ₂ concentration) of the molten slag finally discharged from the electric furnace to a desired concentration. Another object of the present invention is to provide a method for adjusting the component concentration of rock wool molten slag capable of reducing the fluctuation of the component concentration and achieving stable component concentration adjustment and flexible component concentration adjustment when changing the concentration.

[0009]

SUMMARY OF THE INVENTION The present invention is a dual electric furnace.
Concentration of Molten Slag for Rockwool
Based on the results of various experiments, focusing on adjusting
The following is the summary of the
As described above. Claim 1 for achieving the above object.
In the present invention, the molten slag (weight W ₁) One that has stored
Blast furnace molten slag (weight V₀, Component concentration
C₀) Is added and supplied, and a predetermined weight of ingredients is adjusted.
Material is added and the molten slag in the primary electric furnace is used as an electrode.
Gas bubbling while heating
Of the primary molten slag whose degree is adjusted (V₁)
Are placed in series in the primary electric furnace, and the molten slag is previously
(Weight W₂) Is stored in the secondary electric furnace, and the secondary electric furnace is supplied.
Secondary melting in which the concentration of components is adjusted by heating with an electrode inside
Predetermined weight of slag (V ₂) When tapping hot water,
Molten slag stored in an electric furnace (weight W₁), To the primary electric furnace
Blast furnace molten slag to be supplied (weight V₀, Component concentration C₀),
Primary molten slag supplied from the primary electric furnace to the secondary electric furnace
(Weight V₁), Molten slag stored in the secondary electric furnace (weight
W₂) And secondary molten slag from the secondary electric furnace
(Weight V₂) Based on C), the component concentration C of the secondary molten slag₂
Is the desired component concentration C_{2, o}Gas into the primary electric furnace so that
It is characterized by adjusting the flow rate of bubbling gas.
It is a method for adjusting the component concentration of molten slag for cook wool.

According to a second aspect of the present invention, the concentration of the component of the secondary molten slag discharged from the secondary electric furnace is measured, and the measured value of the component concentration is fed back to the rock wool. It is a method of adjusting the component concentration of the molten slag for use. The present invention according to claim 3 is the method for adjusting the component concentration of the molten slag for rock wool according to claim 1 or 2, characterized in that a predetermined amount of the component additive is added to the secondary electric furnace.

[0011]

The structure, operation and effect of the present invention will be described below with reference to the drawings. In the present invention, two electric furnaces are arranged in series. That is, as shown in FIG. 1, the primary electric furnace 8 is installed on the upstream side, and the secondary electric furnace 9 is arranged on the downstream side to form a series. A molten slag (weight W ₁ ) 37 is stored in the primary electric furnace 8, and a blast furnace molten slag (weight V ₀ , SiO ₂ component concentration C ₀ ) 36 in the supply pan 35 is newly provided on the furnace lid 7. It is additionally charged in batches into the primary electric furnace through the charging port 34 and pooled. Then, the lower portions of the plurality of electrodes 5 (usually 3) inserted into the furnace via the furnace lid 7 are immersed in the molten slag 37 in the primary electric furnace 8, and the temperature of the molten slag 37 is increased by the electric power from the electrodes 5. The heating is performed in the same manner as in the past to keep the temperature constant.

In the present invention, the furnace lid 7 that covers the primary electric furnace 8
The gas bubbling lance 1 is inserted almost vertically through the lance insertion port 3 provided corresponding to the central portion of the above, that is, the center position of the three electrodes 5, and the lower portion thereof is immersed in the molten slag 37 in the furnace. Inert gas supply pipe 17 via flexible pipe 23
When the inert gas supplied from (see FIG. 2) is supplied to the gas bubbling lance 1 and blown into the molten slag 37, the inert gas becomes bubbles 11 to form a gas bubbling region in the center of the furnace. It floats up in the molten slag 37.

On the other hand, a component adjusting material charging port 4 is installed in the furnace lid 7 concentrically with the lance insertion opening 3 so as to surround the lance inserting opening 3, and the powdery and granular component supplied from the component adjusting material supply pipe 2 is provided. The adjusting material 10 is directly charged from the component adjusting material charging port 4 onto the surface of the molten slag 37 existing around the gas bubbling lance 1. In this way, the component adjusting material 10 is the molten slag 37
The molten slag 37 in the gas bubbling area is exposed as a bare molten metal surface by the agitating action because the molten slag 37 in the gas bubbling region is exposed directly.
Since it is charged in 37, the dissolution rate will be high and the dissolution will be promoted.

On the other hand, the component adjusting material (generally silica powder containing a large amount of SiO ₂ ) 10 in the peripheral region pushed to the periphery by the gas bubbling formed in the central portion of the primary electric furnace 8 is Although the component adjusting material 10 has a low thermal conductivity, it melts at the contact interface between the molten slag 37 and the component adjusting material 10, but the component adjusting material (silica powder) 10 deposited on it has a temperature higher than that of the molten slag 37. The undissolved component adjusting material 6 having a low value is deposited.

When the undissolved component adjusting material 6 is deposited on the surface of the molten slag 37 around the gas bubbling region as described above, it serves as a heat insulating layer, so that the heat radiated from the surface of the molten slag 37 is reduced. can do. Therefore, as a result of strengthening the heat retention power, it becomes possible to reduce the power supplied from the electrode 5 for heating.

In the present invention, for the primary electric furnace, the component adjusting material melting device 30 can be configured as shown in FIGS. 2 and 3. That is, the component adjusting material dissolving device
The gas bubbling lance 1 provided with 30 is rotatably supported by a lance suspension support portion 12 provided at the tip of the telescopic member 13. The telescopic member 13
It is supported by the arm body 13C via A and 13B so as to be able to extend and contract. A cylinder type expansion / contraction drive device 14 supported by bearings 26A and 26B is mounted between the expansion / contraction arm 13 and arm body 13C. 13 is expanded and contracted, whereby the gas bubbling lance 1 is moved forward and backward.

The arm body 13C is supported so as to be vertically movable by tilting with respect to the vertically movable support member 27 via a horizontal pin 28. Also, the arm body 13C and the vertical movement support member
A cylinder type vertical movement drive unit 15 is attached between the cylinder type vertical movement unit 27 and the cylinder 27, and the cylinder type vertical movement drive unit 15 is tilted via a horizontal pin 28 by expanding and contracting the cylinder type vertical movement drive unit 15. The gas bubbling lance 1 supported by the provided lance suspension support portion 12 is vertically moved. In this case, since the telescopic arm 13 draws a circular arc with the horizontal pin 28 as a fulcrum, in order to move the gas bubbling lance 1 up and down smoothly to the lance insertion port 3, forward and backward movement of the telescopic arm 13 causes forward and backward movement of the gas bubbling lance 1. It works together.

Further, the vertical movement support member 27 is fixedly mounted on a swivel base 25 having a plane circular shape, and a cylinder type swivel drive device 16 is connected to a side portion of the swivel base 25. By expanding and contracting the cylinder type swing drive device 16, the swivel base 25 moves to the central axis 31.
The vertical movement support member 27, which is integrally provided on the swivel base 25, is swung around the swivel base 25, so that the gas bubbling lance 1 can be swung between the operating position 1A and the standby position 1B. You can do it.

The extension / contraction movement amount by the cylinder type extension / contraction driving device 14 is measured by the extension / contraction movement measuring device 18, and the vertical movement amount by the cylinder type vertical movement driving device 15 is measured by the vertical movement amount measuring device.
19, further the amount of swing movement by the cylinder type swing drive device 16 is measured by the swing movement amount measuring device 20, respectively,
These measured values are input to the lance control operation panel 21, and while confirming the position of the gas bubbling lance 1, the gas bubbling lance 1 is automatically inserted into and removed from the lance insertion port 3 according to a command from the lance control operation panel 21. it can. As a matter of course, the gas bubbling 1 can be manually inserted and removed by the lance control operation panel 21 as needed.

In addition, the inert gas to the gas bubbling lance 1 is a gas flow rate regulator installed in the inert gas supply pipe 17 by opening the shutoff valve 24 in response to a command from the lance control operation panel 21.
While adjusting the flow rate at 22, the gas passes through the gas bubbling lance 1 through the inert gas supply pipe 17 and the flexible pipe 23, and is blown into the molten slag 37 in the primary electric furnace 8.

On the other hand, in the secondary electric furnace 9, molten slag (weight:
W₂) 38 is stored in advance and slag is generated in the primary electric furnace 8.
Predetermined amount of molten slag 37 with adjusted components and temperature
(V ₁) Is discharged from the slag discharge port 39, and the secondary electric furnace 9
From the slag charging port 34 provided in the furnace lid 7 of the
Supply and be pooled. And insert into the furnace through the furnace lid 7.
The lower part of the plural (usually three) electrodes 5 put in is put into a secondary electric furnace.
It is dipped in the molten slag 38 inside and the power from the electrode 5
The molten slag 38 is heated so as to keep the temperature constant. What
By the way, the secondary electric furnace 9 does not contain the component adjusting material.
In addition, it is possible to add more from the component adjusting material charging port 4.
Has become.

Next, regarding the operation of the present invention, the primary electric furnace 8
The gas bubbling lance 1 will be described as being at the standby position 1B. First, a predetermined weight (V ₀ ) of the molten slag in the supply pan 35 by-produced in the blast furnace is batch-charged from the slag charging port 34 provided in the primary electric furnace 8. The electrode 5 is inserted into the furnace via the furnace lid 7, and the molten slag 37 is immersed in the molten slag 37 to a predetermined depth, and electric power is supplied from the electrode 5 to start heating the molten slag 37.

The operation of the cylinder-type turning drive device 16 is started in response to a command from the lance control operation panel 21, and the telescopic arm 13 is turned while measuring the turning movement amount by the turning movement amount measuring device 20 and reaches a predetermined position. Then, the operation of the cylinder type swing drive device 16 is stopped in response to a command from the lance control operation panel 21.
Next, the operation of the cylinder type telescopic drive device 14 is started in response to a command from the lance control operation panel 21, and the telescopic members 13B and 13A provided on the arm body 3C are measured while the telescopic movement amount measuring device 18 measures the telescopic movement amount. The telescopic arm 13 is extended via this, and when it reaches a predetermined position, the telescopic drive device 14 is stopped by a command from the lance control operation panel 21. At this time, telescopic arm
The gas bubbling lance 1 supported by a lance suspension support 12 provided at the tip of the furnace 13 has a furnace lid 7 that covers a primary electric furnace 8.
Has reached the upper position 1A of the lance insertion port 3 provided in the central part of the.

Subsequently, the operation of the cylinder type vertical movement drive device 15 is started in response to a command from the lance control operation panel 21, and the vertical movement amount measuring device 19 measures the vertical movement amount, and the gas bubbling lance is passed through the telescopic arm 13. 1 is lowered and inserted into the primary electric furnace 8 from the lance insertion port 3. At this time, since the telescopic arm 13 draws a circular arc with the horizontal pin 28 connecting the arm body 13C to the vertical movement support member 27 as a fulcrum, the gas bubbling lance 1 supported by the telescopic arm 13 matches the position of the lance insertion port 3. As described above, the gas bubbling lance 1 is lowered by interlocking with the expansion and contraction driving device 14. When the gas bubbling lance 1 via the telescopic arm 13 is displaced, the expansion / contraction drive device 14, the vertical movement drive device 15, and the turning drive device 16 are used to correct the position in accordance with the displacement. It goes without saying to do it.

Thus, at the timing when the tip of the gas bubbling lance 1 passes a predetermined position above the molten slag 37 stored in the primary electric furnace 8, the shutoff valve 24 is opened by a command from the lance control operation panel 21 to open the gas. The flow rate controller 22 automatically adjusts the flow rate of the inert gas (here, nitrogen N ₂ gas),
The gas bubbling lance 1 is passed through the inert gas supply pipe 17 and the flexible pipe 23, and the primary electric furnace 8
The blowing of N ₂ gas is started in the inner bath space. By blowing out the N ₂ gas from the gas bubbling lance 1 at such a timing, it is possible to prevent the N ₂ gas from being blown out of the primary electric furnace 8.

Then, from the gas bubbling lance 1 to N ₂
When the gas bubbling lance 1 is immersed to the predetermined depth of the molten slag 37 while blowing gas, the lance control operation panel
The vertical movement drive device 15 is stopped in response to a command from 21. Silica powder containing a large amount of powdery SiO ₂ as a component adjusting material 10 is charged into the central portion of the molten slag 37 through the component adjusting material charging port 4 from the component adjusting material supply pipe 2. If necessary, the molten slag 37 is additionally charged into the primary electric furnace 8. The N ₂ gas blown into the molten slag 37 from the gas bubbling lance 1 becomes bubbles 11 at the center of the molten slag 37 and floats around the gas bubbling lance 1 to form a gas bubbling region.
Since the central part of the molten slag 37 is a bare molten metal surface, the charged component adjusting material can be rapidly dissolved.

On the other hand, the molten slag 37 in the peripheral region of the gas bubbling region formed in the central portion of the electric furnace serves as a heat insulating layer because it is covered with the accumulated undissolved component adjusting material 6 and melts. Radiant heat radiated from the surface of the slag 37 can be reduced. As described above, this can reduce the power supplied from the electrode 5 for heating.

In this way, if a predetermined amount of the silica powder is dissolved as the component adjusting material 10 in the molten slag 37 stored in the primary electric furnace 8 and the molten slag 37 is adjusted to the predetermined temperature by the electrode 5. The gas bubbling lance 1 is removed from the lance insertion port 3 of the primary electric furnace 8 by the procedure reverse to the above, and is returned to the standby position 1B to stand by. After extracting the electrode 5 from the molten slag 37 in the primary electric furnace 8, a predetermined weight (V ₀ ) of the molten slag 37 from the primary electric furnace 8 is taken out.
Are discharged from the slag discharge port 39 and pooled in the secondary electric furnace 9 in which the molten slag (weight W ₂ ) 38 has already been stored.

Subsequently, the electrode 5 is inserted into the furnace through the furnace lid 7, immersed in the molten slag 38 to a predetermined depth, and the molten slag 38 is heated by supplying electric power from the electrode 5. Make the component concentrations uniform. If necessary, the component adjusting material is supplementarily added from the component adjusting material inlet 4,
Usually, addition to the primary electric furnace 8 is sufficient. After the adjustment of the homogenization of the component concentration by heating the molten slag 38 in the secondary electric furnace 9, a predetermined weight (V ₂ ) of the secondary molten slag 38 is tapped from the slag discharge port 39 to produce rock wool. To serve.

The expansion / contraction driving device 14 and the vertical movement driving device 15 provided in the component adjusting material dissolving device 30 shown in FIGS. 2 and 3.
The case where the cylinder type is used as each of the swivel driving device 16 and the swivel driving device 16 has been described. be able to. As the vertical movement drive device, a mechanism in which the vertical movement carriage is moved up and down by a drive device along a vertical guide post so that the gas bubbling lance supported at the tip of the telescopic arm can be moved up and down. It is possible.

In the present invention, the primary electric furnace 8 and the secondary electric furnace 9 are arranged in series as described above, and the primary molten slag whose SiO ₂ component concentration and temperature are adjusted in the primary electric furnace 8 is used as the primary electric furnace 8. When the secondary molten slag that has been adjusted again in the secondary electric furnace 9 is tapped, the concentration of the components of the blast furnace slag is measured, and the weight of the supply pot containing the blast furnace slag and the empty The blast furnace slag weight is measured from the difference with the supply pan weight, the weight of the primary electric furnace is measured to obtain the amount of molten slag in the primary electric furnace, the weight of the secondary electric furnace is measured, and the weight of the secondary electric furnace is measured. Obtain the amount of molten slag, determine the amount of molten slag discharged from the primary electric furnace from the amount of change over time in the weight of the primary electric furnace,
By determining the amount of molten slag discharged from the secondary electric furnace from the amount of change over time in the weight of the secondary electric furnace, and by determining the gas flow rate for making the concentration of the components of the secondary electric furnace the desired concentration based on this information. It enables stable and flexible adjustment of component concentration. Further, by measuring the concentration of the molten slag component discharged from the secondary electric furnace and making a correction when obtaining the gas flow rate, the variation in the component concentration can be further reduced.

That is, as shown in FIG. 4, the primary electric furnace 8
Molten slag (weight W ₁ ) 37, blast furnace molten slag (weight V ₀ , component concentration C ₀ ) 36 supplied to the primary electric furnace, primary molten slag (weight V 1) supplied from the primary electric furnace to the secondary electric furnace ₁ ) Based on 37A, the molten slag (weight V ₂ ) 38 stored in the secondary electric furnace and the secondary molten slag (weight V ₂ ) 38A discharged from the secondary electric furnace, the component concentration C of the secondary molten slag 38A by determining the gas flow rate of gas bubbling in the primary electric furnace required to ₂ to a desired SiO ₂ component concentration C _{2, o,} stable and flexible secondary molten slag 38A
It is possible to adjust the SiO ₂ component concentration of the. Also,
Preferably, the concentration of the molten slag component discharged from the secondary electric furnace is measured, and correction is performed when obtaining the gas flow rate, whereby the variation in the component concentration can be further reduced.

An example of a method for obtaining the gas flow rate from the above data information will be described. The component concentrations of the molten slags 37A and 38A discharged from the primary electric furnace 8 and the secondary electric furnace 9 can be calculated from the mass balance by the following formula. Normally, the addition of the component adjusting material in the secondary electric furnace 9 is zero, so by solving the following two equations (1) and (2) simultaneously, the component concentration C ₂ of the molten slag 38 in the secondary electric furnace 9 Is the target value C _{2, o}
Thus, the SiO ₂ component concentration C ₁ of the molten slag 37 of the primary electric furnace 8 and the component adjusting material dissolution rate k _{1 of the} primary electric furnace 8 can be obtained. So that the k _1, determine the gas flow rate required using the relationship between the gas flow and the component-adjusting material dissolution rate as qualitatively shown in Fig. Further, when the measured value of the molten slag component concentration of the secondary electric furnace is fed back, the relationship between the gas flow rate and the component adjusting material dissolution rate is corrected based on the measured value.

The method of measuring the necessary information and the method of estimating the gas flow rate may be any method without departing from the spirit of the present invention. W ₁ × (dC ₁ / dt) = k ₁ + C ₀ × V ₀ −C ₁ × V ₁ (1) W ₂ × (dC ₂ / dt) = k ₂ + C ₁ × V ₁ −C ₂ × V ₂ (2) C ₀ : Blast furnace slag component concentration C ₁ : Molten slag component concentration of the primary electric furnace C ₂ : Cryogenic slag component concentration of the secondary electric furnace V ₀ : Blast furnace slag supply amount V ₁ : Amount of molten slag discharged from the primary electric furnace V ₂ : Amount of molten slag discharged from the secondary electric furnace W ₁ : Weight of molten slag from the primary electric furnace W ₂ : Weight of molten slag from the secondary electric furnace k ₁ : Primary electricity Amount of dissolved component adjusting material in furnace k ₂ : Dissolved amount of component adjusting material in secondary electric furnace t: Time

[0035]

Embodiments of the present invention will be described below. Example 1 As shown in FIG. 1, a primary electric furnace and a secondary electric furnace arranged in series were used. In the primary electric furnace, the component adjusting material melting apparatus shown in FIGS. 2 and 3 was used to melt rock wool. Adjusted the slag.

Weight as molten slag in primary electric furnace W ₁ =
30-40 tons (35 tons on average) was stored in advance, and weight V ₀ = 4-9 tons (7 tons / hr on average) as blast furnace molten slag and silica powder = 0.6 to 1.8 tons / hr as component adjusting material. Are supplied in batches. Then, from the primary electric furnace to the secondary electric furnace, the weight V ₁ = 4 ~ as the primary molten slag
11 tons / hr (8 tons / hr on average) are tapped in batches.
The cycle of these batches is, for example, 40 minutes.

Further, the weight W ₂ = 15 to 25 tons (average 20 tons) is previously stored as molten slag in the secondary electric furnace, and the weight V ₁ from the primary electric furnace to the secondary electric furnace is stored in this as described above.
= 4-11 tons / hr (8.2 tons / hr on average) is fed in batches, and the weight V ₂ = 4-11 tons / hr (8.2 tons / hr on average) as the secondary molten slag adjusted by heating. Is continuously tapped.

Since the blast furnace molten slag supplied to the primary electric furnace is supplied and tapped in a batch manner, the weight W _{1 of the} molten slag stored in the primary electric furnace varies within the range of 30 to 40 tons. In addition, since the primary molten slag is supplied batchwise from the primary electric furnace to the secondary electric furnace and the secondary molten slag is continuously tapped from the secondary electric furnace, the weight W of the molten slag stored in the secondary electric furnace is W. ₂ varies in the above-mentioned range of 15 to 25 tons.

Within the change range of the molten slag, the average
The points in this state are as follows: (a) Weight W of molten slag in the primary electric furnace₁= 35 tons Melt slag weight W of secondary electric furnace₂= 20 tons of blast furnace molten slag supply weight V₀= 9 tons / hr Silica powder (composition adjusting material) = 1.8 tons / hr Supply weight V from primary electric furnace to secondary electric furnace₁= 10.8 tons
/ Hr Weight of hot water discharged from secondary electric furnace V₂= 10.8 ton / hr SiO of blast furnace molten slag₂Component concentration C₀= 0.33 (33wt%) SiO of secondary electric furnace₂Component concentration C₂= 0.41 (41wt%) Melting rate of silica powder in secondary electric furnace k₂(Gas bubbling
)) = 0.1 ton / hr, the following formula (1) and formula (2)₁X (dC₁/ Dt) = k₁+ C₀× V₀-C₁× V₁ ……… (1) W₂X (dC₂/ Dt) = k₂+ C₁× V₁-C₂× V₂ ……… (2) dC in steady state₁/ Dt = 0, dC₂/ Dt = 0
Therefore, from equation (2), C₁= (V₂/ V₁) × C₂-K₂/ V₁ ……… (3) From equation (1) and equation (3), k₁= C₁V₁-C₀V₀= {(V₂/ V₁) × C₂−
(K₂/ V₁)} × V ₁-C₀V₀= C₂V₂-C₀V
₀-K₂= 0.41 x 10.8-0.33 x 9-0.1 = 1.358 ton /
hr Between the dissolution rate of the component modifier and the amount of bubbling gas shown in Fig.
Using the relationship, the melting amount k of the primary electric furnace₁≒ 1.4 tons / hr
For bubbling in the primary electric furnace required to
N₂The gas flow rate is 230 l / min. In this case, the primary
Gas bubbling lance from the furnace to N₂Gas flow is 230l
/ Min. Secondary molten slag if bubbling operation is carried out.
SiO₂Concentration C₂Target SiO₂Concentration C_{2, o}= 41 wt%
You can (b) In actual operation, the steady state described above does not only continue.
The amount of blast furnace molten slag supplied from the steady state is as follows.
V₀, Of the primary molten slag from the primary electric furnace to the secondary electric furnace
Supply weight V₁And the secondary molten slag from the secondary electric furnace
Hot water weight V₂May fluctuate. That is, the primary
Molten slag weight W of the furnace₁= 35 tons, melting of secondary electric furnace
Slag weight W₂= 20 tons, from primary electric furnace to secondary electric furnace
Supply weight V ₁= 4.6 tons / hr, tap water from the secondary electric furnace
Weight V₂= 4.6 ton / hr, SiO of blast furnace molten slag₂Ingredient concentration
Degree C₀= 0.33 (33wt%), target SiO₂Component concentration C₂= 0.41
(41wt%), dissolution rate of silica powder in secondary electric furnace k₂= 0.1 g
K / hr₁= C₂V₂-C₀V₀-K₂=
0.41 x 4.6 -0.33 x 4-0.1 ≈ 0.46 tons / hr
6 to N for gas bubbling of primary electric furnace₂Gas flow
Is 10 l / min.

Therefore, from the primary electric furnace to the secondary electric furnace
Molten slag supply weight V₁If the fluctuates, the primary electric furnace
Molten slag weight W₁And molten slag weight of secondary electric furnace
Quantity W ₂Fluctuates, and the silica stone powder dissolution rate k in the primary electric furnace₁Key
If not adjusted, SiO in molten slag of the primary electric furnace₂Component concentration C
₁Fluctuates, and eventually SiO in the molten slag of the secondary electric furnace₂Ingredient concentration
Degree C₂Fluctuates. Therefore, equation (1) and equation (2)
Dissolution rate k of silica powder in the primary electric furnace based on₁Decide and figure
N for gas bubbling determined from 6₂Adjust the gas flow rate
Need to be adjusted.

By the way, in the conventional method, since the gas flow rate of the gas bubbling is appropriately adjusted without determining the gas flow rate of the gas bubbling based on the required operation amount as in the present invention, the SiO _{2 of} the molten slag discharged from the electric furnace is changed. SiO ₂ component concentration by such action is delayed with respect to fluctuations in component concentration C ₂ is (41 ± 1.5
) Wt%, but with the method of the present invention, (41 ± 0.7) wt
Could be improved to%. Example 2 In Example 1 of the present invention, the molten metal weight V ₁ from the primary electric furnace, the molten metal weight V ₂ from the secondary electric furnace, the SiO ₂ component concentration C _{0 of} the blast furnace molten slag, and the component of the secondary electric furnace The SiO ₂ component concentration C _{2 of the} secondary molten slag discharged from the secondary electric furnace is changed to a target value C ₂ due to the fluctuation of the silica stone powder dissolution rate k ₂ for adjustment.
_When the component concentration deviation ΔC ₂ = C ₂ −C _{2, o} does not occur, the flow rate of the N ₂ gas for gas bubbling in the primary electric furnace is changed as follows.

The condition (a) of the first embodiment, that is, W ₁ =
35 t, W ₂ = 20 Ton, V ₀ = 9 Ton hr, silica powder = 1.8
Tons / hr, V ₁ = 10.8 tons / hr, V ₂ = 10.8 tons / hr,
C ₀ = 0.33 (33 wt%), target C _{2, o} = 0.41 (41 wt%),
When k ₂ = 0.1 ton / hr, the target SiO ₂ component concentration C _{2, o of the} secondary molten slag discharged from the secondary electric furnace is k,
As described above, ₁ = 1.358 ton / hr and the N ₂ gas flow rate is 230 l / min. As a result of operating under these conditions, when the molten slag component concentration C _{2 in the} secondary electric furnace changes to C ₂ = 0.40 due to changes in the amount of dissolution of the SiO ₂ component adjusting material k _{2 in the} secondary electric furnace, equation (1) and From (2), the dissolved amount k ₁ of the SiO ₂ component adjusting material in the primary electric furnace is k ₁ = C ₂ V ₂ −C ₁ V ₀ −k ₂ = 0.40 × 10.8−0.33 ×
9-0.1 = 1.25 seek ton / hr, a gas flow rate 250l corresponding to k ₁ = 1.25 from FIG. 6
/ Min, and the gas correction amount ΔQ becomes as follows.

ΔQ = {(230-200) / (1.358-1.25)} ×
(1.358-1.25) = 30 l / min Therefore, N blown from the bubbling gas into the primary electric furnace
₂ SiO ₂ component concentration C _{2 of the} secondary molten slag discharged from the secondary electric furnace with the gas flow rate changed to 230 + ΔQ = 260 l / min
_Can be adjusted to the target value C _{2, o} . With this method, the fluctuation of the SiO ₂ component concentration is 41 ± 0.4 wt.
I was able to improve to%.

[0044]

As described above, according to the present invention,
Molten slag stored in the next electric furnace (weight W ₁), Primary electric furnace
Blast furnace molten slag (weight V₀, Component concentration
C₀), Primary melting supplied from the primary electric furnace to the secondary electric furnace
Slag (weight V₁), Molten slag stored in the secondary electric furnace
(Weight W₂) And secondary molten smelt coming from the secondary electric furnace
Rug (weight V₂) Based on the component concentration of the secondary molten slag
Bubbling in the primary electric furnace to achieve the desired concentration
Since the gas flow rate to be adjusted is adjusted,
Dissolution concentration C of the component adjusting material of the secondary molten slag that is tapped₂
Fluctuations to reduce the component concentration in a stable state to the target value.
Adjustments can be made. Also, when adjusting the component concentration,
It is possible to achieve the ingredient concentration in a kisible manner, and
The quality of the roll is stable and it depends on the amount of rock wool produced.
Flexible operation is easily achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall arrangement of a device according to the present invention.

FIG. 2 is a cross-sectional view showing a component adjusting material dissolving device according to the present invention.

FIG. 3 is a plan view showing the component adjusting material dissolving device of FIG.

FIG. 4 is a flow chart showing a material balance according to the present invention.

FIG. 5 is a diagram qualitatively showing a relationship between a dissolution rate of a component adjusting material and a flow rate of bubbling gas.

FIG. 6 is a graph showing quantitatively the relationship between the dissolution rate (ton / hr) of SiO ₂ component adjusting material and the flow rate of bubbling gas.

[Explanation of symbols]

 1 gas bubbling lance 2 component adjusting material supply pipe 3 lance insertion port 4 component adjusting material inlet 5 electrode 6 undissolved component adjusting material 7 furnace lid 8 primary electric furnace 9 secondary electric furnace 10 component adjusting material 11 bubble 12 lance suspension support Part 13 Telescopic arm 14 Telescopic drive device (cylinder type) 15 Vertical motion drive device (cylinder type) 16 Revolving drive device (cylinder type) 17 Inert gas supply pipe 18 Telescopic movement amount measuring device 19 Vertical movement amount measuring device 20 Swiveling Moving amount measuring instrument 21 Lance control operation panel 22 Gas flow regulator 23 Flexible pipe 24 Shut-off valve 25 Swiveling base 26 Bearing 27 Vertical movement support member 28 Horizontal pin 30 Component adjusting material melting device 31 Central shaft 34 Slag loading port 35 Supply pan 36 Blast furnace molten slag 37 Molten slag (primary) 38 Molten slag (secondary) 39 Slag outlet

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Isao Tamakoshi 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (No house number) Inside the Mizushima Works, Kawasaki Steel Co., Ltd. 1-chome (without street number) Inside Kawashima Steel Co., Ltd. Mizushima Steel Works (72) Inventor Norio Misaki 1-chome (without street number) Mizushima Kawasaki-dori, Kurashiki City, Okayama Prefecture

Claims (3)

[Claims] 1. Molten slag (weight W)₁) One that has stored
Blast furnace molten slag (weight V₀, Component concentration
C₀) Is added and supplied, and a predetermined weight of ingredients is adjusted.
Material is added and the molten slag in the primary electric furnace is used as an electrode.
Gas bubbling while heating
Of the primary molten slag whose degree is adjusted (V₁)
Are placed in series in the primary electric furnace, and the molten slag is previously
(Weight W ₂) Is stored in the secondary electric furnace, and the secondary electric furnace is supplied.
Secondary melting in which the concentration of components is adjusted by heating with an electrode inside
Predetermined weight of slag (V₂) When tapping hot water,
Molten slag stored in an electric furnace (weight W₁), To the primary electric furnace
Blast furnace molten slag to be supplied (weight V₀, Component concentration C₀),
Primary molten slag supplied from the primary electric furnace to the secondary electric furnace
(Weight V₁), Molten slag stored in the secondary electric furnace (weight
W₂) And secondary molten slag from the secondary electric furnace
(Weight V₂) Based on C), the component concentration C of the secondary molten slag₂
Is the desired component concentration C_{2, o}Gas into the primary electric furnace so that
It is characterized by adjusting the flow rate of bubbling gas.
Method for adjusting component concentration of molten slag for cook wool. 2. The component concentration adjustment of the molten slag for rock wool according to claim 1, wherein the component concentration of the secondary molten slag discharged from the secondary electric furnace is measured, and the measured value of the component concentration is fed back. Method. 3. The method for adjusting the component concentration of a molten slag for rock wool according to claim 1, wherein a predetermined amount of the component additive is added to the secondary electric furnace.