JP2002003919A - Method for preventing red fume in handling of molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the generation of red fume when molten metal such as molten iron or molten steel, is poured. SOLUTION: For example, when the molten iron is poured into a molten iron ladle 5A from a mixer car 2A, a water atomizing mechanism 8 is arranged at the upper part of the molten iron ladle 5A and steam is generated by spraying water to the molten iron stream from this water atomizing mechanism 8 and oxygen concentration in the molten iron ladle 5A is lowered to <=12%, desirably <=8% to restrain or prevent the generation of the red fume.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing red smoke during molten metal handling, which prevents red smoke generated when pouring molten metal such as molten iron or molten steel into a receiver.

[0002]

2. Description of the Related Art Conventional methods for preventing red smoke during handling of molten metal, such as hot metal or molten steel, are disclosed, for example, in JP-A-49-9405 (hereinafter referred to as a first conventional example) and JP-A-9-96492. Japanese Patent Application Publication (hereinafter referred to as a second conventional example).

[0003] In the first conventional example, when hot metal is discharged into a receiver, a container is previously filled with an inert gas or spray water, and then the hot metal is discharged into the container. A dust prevention method is disclosed. Further, in the second conventional example, when pouring hot metal into a container, an inert gas is blown into the container prior to the pouring to remove air to make the atmosphere in the container inert. A red smoke prevention method at the time of handling hot metal, in which pouring is performed while supplying an inert gas into the container thereafter, is disclosed.

[0004]

However, when an inert gas is used as in the first and second conventional examples, the effect of suppressing red smoke is obtained with a ladle scale of, for example, 150 tons. For this purpose, an inert gas of about 20,000 Nm ³ / H is required, which is not practical due to an increase in cost, and it is difficult to stably supply the inert gas due to instantaneous use of a large amount of the inert gas. However, there is an unsolved problem that it can be used for experiments but cannot be implemented on a factory scale.

As in the first conventional example, it is more realistic to use spray water instead of the inert gas from the viewpoint of the effect of suppressing red smoke and economy, but in order to form an appropriate inert atmosphere. It does not describe how to control the amount of spray water, and there is an unsolved problem that the reality is poor. Accordingly, the present invention has been made in view of the unsolved problems of the above-described conventional example, and it is possible to appropriately control the amount of sprayed water to suppress the generation of red smoke. It aims to provide a smoke prevention method.

[0006]

In order to achieve the above object, a method for preventing red smoke at the time of handling molten metal according to claim 1 is characterized in that a molten metal such as hot metal or molten steel is poured into a receiver. In the method of preventing red smoke during molten metal handling in which the generation of red smoke is prevented, when pouring the molten metal into the pig receiver, water is sprayed into the pig receiver by water spraying means. Then, the spray amount of the water is controlled so that the oxygen concentration in the pig receiver becomes 12% or less, thereby preventing generation of red smoke.

According to the first aspect of the present invention, when a molten metal such as hot metal or molten steel is poured into a receiver, the amount of water sprayed into the receiver is determined by the oxygen concentration in the receiver. Is controlled so as to be 12% or less, so that the amount of generated red smoke is 1 compared with the amount of generated red smoke when the oxygen concentration exceeds 12%.
/ 3 or less. That is, when pouring hot metal into the ladle, an experiment was conducted in which wood was burned in the ladle, and the relationship between the oxygen concentration in the ladle and the generated dust concentration was measured. as shown, when the oxygen concentration exceeds 12%, although the dust concentration that occur when pouring the hot metal in the ladle becomes 6~11g / Nm ³ or so, the oxygen concentration below 12% By suppressing the concentration, the dust concentration generated during pouring into the ladle can be suppressed to about one third or less of about 2 g / Nm ³ , and the generation of red smoke can be suppressed.

According to a second aspect of the present invention, there is provided the method for preventing red smoke during molten metal handling according to the first aspect of the present invention, wherein the water spray amount is adjusted so that the oxygen concentration in the receiver is 8% or less. It is characterized by controlling. According to the second aspect of the present invention, since the amount of water spray is set so that the oxygen concentration in the receiver becomes 8% or less, generation of red smoke can be almost completely prevented.

That is, from the experimental results shown in FIG.
The dust concentration when the oxygen concentration is 8% or less becomes substantially zero, and the generation of red smoke can be reliably prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a front view and a side view, respectively, showing a raw material yard of a steelmaking plant to which the present invention can be applied. In the drawings, 1A and 1B arrive at mixed iron wheels 2A and 2B containing hot metal from a blast furnace. Hot metal pots 5A, 5B as an iron receiver having a pair of left and right platforms and a traveling cart 4 into which hot metal is poured from mixed iron wheels 2A, 2B in a concave portion 3 formed between the platforms 1A, 1B. Platform 6 is formed.

Left and right guide rails 7F and 7R are laid at the upper ends of the front and rear side walls forming the recess 3, and the hood cart 8 is movably arranged in the left and right direction guided by the guide rails 7F and 7R. Have been. This hood cart 8
Are machine frames 10F, 10R having traveling wheels 9 engaged with the guide rails 7F, 7R, a transverse frame 11 bridged between the machine frames 9F, 9R, and dust collection disposed on the transverse frame 11. It comprises a hood 12 and a water spray mechanism 13.

Here, the dust collecting hood 12 includes a central hood portion 12a fixed to the traversing frame 11, and a rotating hood portion 12 protruding left and right from the central hood portion 11a.
b, 12c, when the hood cart 8 is at a position facing the hot metal ladle 5A on the platform 1A side from above, the rotating hood 12b is in a horizontal state and covers the upper part of the mixed iron wheel 2A, and is rotated. When the hood 12c is inclined downward and to the right and collects dust generated in the hot metal pot 5A, and when the hood cart 8 is at a position facing the hot metal pot 5B on the side of the platform 1B from above, the rotating hood 12b is at the lower left. The dust generated in the hot metal ladle 5B in the inclined state is collected, and the rotating hood 12c covers the upper part of the mixed iron wheel 2B.

As shown in FIGS. 3 to 5, the water spray mechanism 13 extends in the front-rear direction at a position near the center of the traversing frame 11, and is pivotally disposed by a pair of front and rear bearings 14 so as to be rotatable. 15, a rectangular cylinder 16 having one end fixed to the rotating shaft 15 and extending downward and covered with a heat insulating plate, and a plurality of spray nozzles 17a disposed at the tip of the rectangular cylinder 16 2 and 3 pairs of headers 18A and 18 provided with
B, water supply pipes 19A and 19B which pass through the inside of the rectangular cylindrical body 16 for supplying water to the headers 18A and 18B, are exposed to the outside from the middle, and are disposed along the rotating shaft 15, and the water supply pipes 19A and 19B. Are provided with flexible hoses 20A and 20B connected to the ends of the shafts via joints, and a rotating mechanism 21 for rotating the rotating shaft 15.

Here, the header 18A is disposed such that the spray nozzles 17a to 17f provided on the header 18A are inclined 145 ° counterclockwise with respect to the center axis of the rectangular cylinder 16 as shown in FIG. Also, the header 18B is disposed in a state where the spray nozzles 17a to 17f provided on the header 18B are inclined 130 ° clockwise with respect to the central axis of the rectangular cylinder 16. Each of the spray nozzles 17a to 17f employs a conical nozzle having a circular spray pattern and a uniform flow distribution, and a standard pressure of 2 kg / cm ^2.
The injection angle is set to 80 °, the injection amount is set to 28 (l / min), and the average particle size is set to about 830 μm.

As shown in FIGS. 3 and 4, the rotating mechanism 21 includes a rotating lever 2 fixed to the right end of the rotating shaft 15.
2 and a power cylinder 23 one end of which is rotatably mounted on the traversing frame 11, and a piston rod 24 of the power cylinder 23 is rotatably mounted on the tip of the rotation lever 22, By controlling the amount of elongation, the rectangular cylinder 16 is inclined at an angle of, for example, about 5 ° in a counterclockwise direction with respect to the vertical line shown by the solid line in FIG. The rotation control between the inclined position for the hot metal pot 5B inclined approximately 20 ° clockwise and the maintenance position inclined approximately 70 ° counterclockwise with respect to the vertical line shown by the two-dot chain line in FIG. Is done.

Further, the other ends of the flexible hoses 20A and 20B connected to the headers 18A and 18B, respectively.
As shown in FIG. 5, the water supply control unit 30 provided on the ground
It is connected to the. The water supply control unit 31 includes a pump 33 whose suction side is connected to a water supply source via a shutoff valve 32, a flow control valve 34, a damper valve 35, and an electromagnetic on-off valve 36 which are sequentially connected to a projecting side of the pump 33. A water supply system 38 having a pressure control valve 37; a flow control valve 39 connected to a nitrogen gas source as an inert gas;
And the output side of the shut-off valve 37 of the water supply system 38 and the output side of the electromagnetic opening / closing valve 40 of the purge system 41 are connected to each other, and the connection ends are branched to open and close, respectively. Flexible hose 20 via valves 42 and 43
A and 20B.

The pump 3 of the water supply control unit 31
3. Flow control valves 34, 39 and solenoid on-off valves 36, 40,
42 and 43 are controlled by a controller 44. The controller 44 is connected to a water supply switch 45 for supplying water to the header 18A side operated by the operator and a water supply switch 46 for supplying water to the header 18B side. Prior to the start of pouring into the pan 5A, when the operator turns on the water supply switch 45, first, nitrogen gas is supplied to the header 18A and spray nozzles 17a to 17
f, and then nitrogen gas is spray nozzle 1
Water supply is started after a lapse of time sufficient to discharge from the nozzles 7a to 17f.
7f, when a sufficient time has passed for forming water mist from the spray nozzles 17a to 17f, the supply of nitrogen gas is cut off, and the state shifts to a water-only spray state. Hot metal pot 5A at the time of hot metal pouring
The flow rate and pressure of the feed water are controlled so that the oxygen concentration in the inside becomes 12% or less, preferably 8% or less.

Thereafter, at the end of the water supply, the nitrogen gas is supplied in the water supply state, and then the nitrogen gas is supplied to the spray nozzles 17a to 17a.
After a lapse of a predetermined time sufficient to reach 17f, the water supply is stopped, and the flexible hose 20A, the water supply pipe 19A
After a lapse of time sufficient to remove the water in the header 18A before the eyes, the supply of the nitrogen gas is stopped. Next, the operation of the above embodiment is described by the controller 4 of the water supply control unit 31.
4 will be described with reference to a flowchart of FIG. 6 showing an example of a water supply control processing procedure executed in Step 4.

In this water supply control process, first, in step S1
Then, it is determined whether or not the water supply switch 45 for supplying water to the header 18A is turned on. When the water supply switch 45 is turned on, the process proceeds to step S2 and the electromagnetic on-off valves 40 and 4 are turned on.
2 is controlled to the open state, and then the process proceeds to step S3.
Nitrogen gas spray nozzle 17a in header 18A
A predetermined time T1 required to discharge from the tip of ~ 17f
It is determined whether or not the predetermined time T1 has elapsed. If the predetermined time T1 has not elapsed, the process waits until the predetermined time T1 has elapsed. If the predetermined time T1 has elapsed, the process proceeds to step S4 to drive the pump 33 and to operate the electromagnetic switching valve. After controlling 36 to the open state, the process proceeds to step S5.

In this step S5, water supply is started and water is sprayed on the spray nozzles 17a to 17f in the header 18A.
It is determined whether or not a predetermined time T2 sufficient to be in a state of discharging from the front end has elapsed, and if the predetermined time T2 has not elapsed, the process waits until the predetermined time T2 has elapsed, and if the predetermined time T2 has elapsed, The process proceeds to step S6, where the electromagnetic on-off valve 40 is controlled to be closed, and then proceeds to step S7.

In this step S7, the water supply flow rate and the water supply pressure are controlled such that the oxygen concentration in the hot metal ladle 5A becomes the target water spray amount Q ^* (l / min) of 12% or less, preferably 8% or less. Here, when the hot metal is poured into the hot metal pot 5A, a downward flow of outside air is generated on the inner peripheral surface side of the hot metal pot 5A, as shown in FIG. This convection occurs, and this updraft occupies 80% of the cross-sectional area of the hot metal ladle 5A, as shown in FIG. 7B. Since this rising air current contacts the hot metal to be poured,
Red smoke is generated.

The mechanism of the generation of this red smoke is based on the fact that the amount of generated red smoke is less when pouring molten steel between when pouring molten iron and when pouring molten steel. It was confirmed that it was due to the same bubble burst phenomenon as the dust generation mechanism in smelting. That is, at the time of hot metal pouring, splashing particles having a particle size of about 100 μm containing iron Fe and carbon C are generated, and the oxygen affinity of carbon C in the splashing particles is strong and oxidizes before iron Fe,
By gasifying into carbon monoxide CO, the splashing particles expand rapidly in volume, and cannot withstand this volume expansion and explode, resulting in finer iron Fe particles of about several μm. It was confirmed that this oxidized to red smoke. As a result, it has been found that in order to suppress red smoke, the oxygen concentration may be controlled so that the fine iron Fe particles are not oxidized.

Therefore, since the inactive state in the hot metal pot 5A changes due to air entering from outside the system due to the convection in the hot metal pot 5A, the oxygen concentration in the hot metal pot 5A is reduced by water spray.
Keep below 2%. That is, the oxygen concentration (%) and the amount of generated dust (g) when pouring hot metal using a 60-ton ladle
/ Nm ³ ), as shown in FIG. 8, as shown in FIG. 8, when the abscissa indicates the oxygen concentration and the ordinate indicates the dust concentration, when the oxygen concentration exceeds 12%, The generated dust concentration shows a high value of 6 to 11 g / Nm ³ ,
Although a large amount of red smoke is generated, when the oxygen concentration is 12% or less, the generated dust concentration is 2 g / Nm ³ or less, and the generation of red smoke can be suppressed to about 1/3 or less. The dust concentration at which the oxygen concentration is 8% or less is approximately 0
g / Nm ³ , indicating that the generation of red smoke can be reliably prevented.

Therefore, the oxygen concentration in the hot metal pot 5A is set to 1
By controlling it to 2% or less, the generation of red smoke can be suppressed. However, the target water spray amount Q ^* at the spray nozzles 17a to 17f for maintaining the oxygen concentration at 12% or less is: The inside diameter of the hot metal pot 5A is D (m),
The rising flow rate from A is v (m / s), and the guesswork determination constant is k
(The value is empirically around 3), it can be calculated by the following equation (1).

Q ^* ≧ kπD ² v (1) The target water supply amount Q is maintained such that the target water spray amount Q ^* is maintained.
W ^* and the target water supply pressure PW ^* are set, and the flow rate of the water supply system 38 is set to a flow meter 4 disposed on the outlet side of the pressure control valve 37.
7, and the pressure is similarly detected by a pressure gauge 48 disposed on the outlet side of the pressure control valve 37. The flow rate detection value Q and the pressure detection value P indicate the target water supply amount QW ^* and the target water supply pressure PW.
^* Feedback control to maintain.

Then, the process proceeds to step S8 to determine whether or not the water supply switch 45 has been turned off. If the water supply switch 45 has been kept on, the process returns to step S7. If the water supply switch 45 has been turned off, the process returns to step S9. Then, the electromagnetic on / off valve 40 is opened, the supply of nitrogen gas is started, and then the process proceeds to step S10, where it is determined whether or not a predetermined time T3 of about several seconds has elapsed. If it has not elapsed, it waits until it has elapsed, and the elapsed time T
When 3 has elapsed, the process proceeds to step S11 to control the electromagnetic on-off valve 36 to be closed, and then to step S12, where the flexible hose 20A, the water supply pipe 19A,
It is determined whether or not a predetermined time T4 required for completely discharging the water inside the header 18A has elapsed. If the predetermined time T4 has not elapsed, the process waits until the predetermined time T4 has elapsed. Shift to S13,
After controlling the electromagnetic on-off valve 42 to the closed state,
Return to 1.

On the other hand, if the result of the determination in step S1 is that the water supply switch 45 is off, the process proceeds to step S14, where the water supply switch 46 for starting water supply to the hot metal pot 5B is on. It is determined whether or not this is the off state, and returns to the step S1 if it is in the off state;
6, the electromagnetic on-off valve 43 is controlled to open in place of the electromagnetic on-off valve 42 in step S15, and the electromagnetic on-off valve 43 is controlled to be closed in place of the electromagnetic on-off valve 42 in step S26. Except for determining whether or not the water supply switch 46 is in the off state in S21, the same processing as the above-described processing in steps S2 to S13 is performed, and then the process returns to step S1.

Therefore, when hot metal is not being poured from the pig iron wheels 2A and 2B into the hot metal ladles 5A and 5B, the water supply switches 45 and 46 are both in the OFF state. Then, step S1 and step S14 are repeated, and each of the electromagnetic on-off valves 36, 40,
42 and 43 are closed, and the supply of water and the supply of nitrogen gas to the spray nozzles 17a to 17f of the headers 18A and 18B are stopped.

In this state, when the mixed iron wheel 2A arrives at the platform 1A and the molten iron is poured from the mixed iron wheel 2A into the hot metal ladle 5A, first, the hood cart 8 is moved to a position above the hot metal ladle 5A. At the same time, by controlling the rotation of the rotation lever 24 to the position shown by the solid line in FIG. 4 by the rotation mechanism 21 of the water spray mechanism 13, the spray nozzles 17a to 17f of the header 18A are supplied with hot metal as shown by the solid line in FIG. It is in a state of facing the downflow path at an inclination angle of 60 ° from the horizontal plane.

In this state, the operator turns on the water supply switch 45 immediately before tilting the mixed iron wheel 2A to start pouring molten iron into the molten iron pot 5A. Accordingly, in the water supply control process of FIG. 6, the process shifts from step S1 to step S2. First, nitrogen gas is injected from the spray nozzles 17a to 17f of the header 18A, and in this state, the pump 33 is driven to rotate, The electromagnetic on-off valve 36 is opened, and water supply to the spray nozzles 17a to 17f of the header 18 is started. At this time, the spray nozzles 17a-
Since nitrogen gas is first injected into 17f, this injected gas and water are mixed together, and even when the discharge pressure of the pump 33 is low immediately after the start of water supply, a water mist state having a small particle diameter is formed and hot metal is formed. Sprayed. By the way, spray nozzle 17a
If water supply is started directly without spraying nitrogen gas at the time of starting water spraying at １７17f, dripping may occur due to the low discharge pressure of the pump 33, and the hot metal pot 5A without evaporating the water droplets. When hot metal is poured in this state, steam explosion may occur. However, in the present embodiment, water mist is formed even at the start of water supply, and the occurrence of dripping can be reliably prevented.

In this state, when the hot metal is poured into the hot metal ladle 5A, the water mist sprayed from the spray nozzles 17a to 17f is directly sprayed on the hot metal, and thereafter, after a predetermined time T2 elapses, the electromagnetic switching is performed. When the valve 40 is closed,
Only the water is supplied to the spray nozzles 17a to 17f of the header 18A.
It is sprayed with a particle size of about 17f to 830 µm. When the spray water sprayed comes into contact with the hot metal, it is instantaneously vaporized, and the generated steam is heated by the hot metal flow into the hot metal ladle 5A.
The hot metal ladle 5A is filled with steam.
The flow rate and pressure of the water supply system 38 are feedback-controlled so that the spray amount at this time becomes the target water spray amount Q ^* .

As described above, the spray nozzles 17a to 17
By controlling the water spray amount sprayed from f to the hot metal to the target water spray amount Q ^* , the oxygen concentration in the hot metal pot 5A is reduced to 12% or less. At this time, the oxygen concentration is 12
%, It is possible to reduce the amount of generated red smoke by more than 1/3 as compared with the amount of generated red smoke when the oxygen concentration exceeds 12%. Controlling to 8% or less can reliably prevent generation of red smoke.

Thereafter, when the pouring of the hot metal is completed, the operator switches the water supply switch 45 to the off state, so that the electromagnetic on-off valve 40 is first controlled to the open state, and the nitrogen gas is supplied to the spray nozzles 17a to 17a of the header 18A. 17f, the nitrogen gas is supplied to the spray nozzles 17a-1
7f, the water mist having a small particle size is sprayed as described above, and in this state, the electromagnetic on-off valve 3
By controlling 6 to be in the closed state, the water supply is stopped.

As a result, only the nitrogen gas is supplied to the flexible hose 20A, the water supply pipe 19A, and the header 18A to be in a purge state, all remaining moisture is discharged from the spray nozzles 17a to 17f, and the purge is completed. At this point, the electromagnetic on-off valve 42 is closed, and then the electromagnetic on-off valve 40 is closed, whereby the supply of the nitrogen gas to the header 18A is also shut off. For this reason, it is possible to reliably prevent water dripping even at the end of water supply, to perform a safe water supply stop, and to ensure that no water droplets remain in the water supply path at the start of the next spraying. It can be performed.

Since nitrogen gas, which is an inert gas, is used as the purging gas, the nitrogen gas accumulates at the bottom of the hot metal pot 5A or 5B at the time of purging. It has the effect of lowering the oxygen concentration in the interior. When pouring hot metal from the pig iron wheel 2B into the hot metal pot 5B on the platform 1B side, the hood cart 8 is moved to a position facing the hot metal pot 5B as shown by a dashed line in FIG. , Water spray mechanism 13
4, the nozzles 16a to 17f of the header 18B are tilted by 60 degrees with respect to the horizontal plane as shown by a chain line in FIG. In this state, the oxygen concentration in the hot metal ladle 5B is reduced to 12% or less, preferably 8% or less by facing the hot metal flow path from the mixed iron wheel 2B and performing water supply control in the same manner as described above in this state. By controlling, generation of red smoke can be suppressed or prevented.

In the above embodiment, the mixed iron wheel 2
When pouring hot metal from A or 2B to hot metal ladle 5A or 5B as a receiver, the case of suppressing or preventing the generation of red smoke has been described, but is not limited thereto.
As shown in FIG. 9, when pouring hot metal from a blast furnace and flowing along a hot metal gutter 50 through a hot metal gutter 51 into a mixed iron wheel 2A or 2B as an iron receiver, the mixed iron wheel 2A or 2
By arranging the above-described water spray mechanism 13 so that the spray nozzle faces the molten iron flow at the pouring port of B, the generation of red smoke can be suppressed or prevented, and
As shown in FIG. 10, when the molten steel is discharged from the ladle 60 to the pig iron trough 61 as the pig receiver, and when the molten steel is poured from the pig trough 61 to the casting machine 62 as the pig receiver, the molten steel is also taken out. Spray nozzles 63 and 64 are provided at the pouring positions between the pan 60 and the receiving trough 61 and between the receiving trough 61 and the cast iron machine 62, respectively. By controlling the oxygen concentration in the vicinity of the road to 12% or less, it is possible to suppress or prevent the generation of red smoke. In addition, when pouring hot metal from the hot metal ladle to the converter or when melting molten steel from the converter to the ladle. The present invention can be applied to pouring any hot metal or molten steel into a receiver such as a pot, a gutter, a mold, etc. at the time of pouring.

Further, in the above embodiment, the water spray mechanism 13 is provided on the hood carriage 8 and the mixed iron wheels 2A and 2B
Although the description has been given of a case in which the generation of red smoke during pouring into the hot metal ladles 5A and 5B is described above, the present invention is not limited to this, and a separate water spray mechanism may be provided. Further, in the above embodiment, the spray angle is 8
At 0 °, the spray amount is 28 l / min and the average particle size is 830 μm
Although the case where it is set to the degree was explained, these specifications are set by the formula (1) according to the size and pouring amount of the hot metal pot to be applied. It is only necessary that the generated steam can reduce the oxygen concentration around the hot metal flow to 12% or less, preferably 8% or less.

Furthermore, in the above embodiment, the case where nitrogen gas is applied for purging has been described.
The present invention is not limited to this, and air may be used instead of nitrogen gas. In this case, the gas use cost can be reduced. It can also be used as Still further, in the above embodiment, the header 18 in which the oxygen concentration in the hot metal pots 5A and 5B is 12% or less, preferably 8% or less.
A and 18B have been described in which the target spray amount Q ^* is set, and the pressure and flow rate of the water supply system 38 are controlled so as to maintain the target spray amount Q ^* . However, the present invention is not limited to this. Instead, the oxygen concentration in the hot metal pots 5A and 5B is directly measured by an oxygen concentration meter, and the flow rate and pressure of the water meter 38 are feedback-controlled so that the measured oxygen concentration is 12% or less, preferably 8% or less. You may.

In the above embodiment, the water supply system 38 is operated by the operation of the water supply switches 45 and 46 by the operator.
And the case where the purge system 41 is automatically controlled has been described. However, the present invention is not limited to this.
Detection of the start of hot metal pouring from
And the purge system 41 may be controlled. Further, the water supply system 38 and the purge system 4 may be controlled manually by an operator.
1 may be controlled.

[0040]

As described above, according to the first aspect of the present invention, when pouring molten metal such as hot metal or molten steel into a receiver, it is possible to spray water into the receiver. By controlling the amount so that the oxygen concentration in the receiver becomes 12% or less, the amount of generated red smoke is reduced to 1/3 of the amount of red smoke generated when the oxygen concentration exceeds 12%. In addition to the above, the cost can be significantly reduced as compared with the case where an inert gas is used, and an oxygen deficiency state occurs due to the inert gas overflowing from the pig receiver when using the inert gas. Without this, an effect that a good working environment can be obtained can be obtained.

According to the second aspect of the present invention, since the amount of water spray is set so that the oxygen concentration in the receiver becomes 8% or less, the generation of red smoke is almost completely prevented. Is obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment in which the present invention is applied to a raw material yard of a steelmaking plant.

FIG. 2 is a plan view of FIG.

FIG. 3 is a front view showing an example of a water spray mechanism.

FIG. 4 is a right side view of FIG. 3;

FIG. 5 is a system diagram showing a water supply system of a water spray mechanism.

FIG. 6 is a flowchart illustrating an example of a water supply control process.

FIG. 7 is an explanatory diagram illustrating a convection state in a hot metal pot.

FIG. 8 is a characteristic diagram showing experimental results of oxygen concentration and dust concentration.

FIG. 9 is a front view showing a blast furnace to which the present invention can be applied;

FIG. 10 is an explanatory view showing a state in which molten steel to which the present invention can be applied is poured into a casting machine using a receiving gutter.

[Explanation of symbols]

 2A, 2B Mixed iron wheel 5A, 5B Hot metal pot 8 Hood truck 13 Water spray mechanism 16 Square cylinder 18A, 18B Header 17a-17f Spray nozzle 19A, 19B Water supply pipe 20A, 20B Flexible hose 21 Rotating mechanism 31 Water supply control unit 33 Pump 34 Flow control valve 36 Electromagnetic on-off valve 37 Pressure control valve 40, 42, 43 Electromagnetic on-off valve 44 Controller 45, 46 Water supply switch 47 Flow meter 48 Pressure gauge 50 Receiving gutter 51 Incline gutter 60 Ladle 61 Reclining gutter 62 Cast iron Machine

Claims (2)

[Claims] 1. A method for preventing red smoke during molten metal handling wherein molten metal such as hot metal or molten steel is poured into a receiver to prevent the generation of red smoke. When pouring into the vessel, water is sprayed into the receiver by water spraying means, and the spray amount of the water is controlled so that the oxygen concentration in the receiver is 12% or less. A method for preventing red smoke during handling of molten metal, wherein smoke is prevented from being generated. 2. The method according to claim 1, wherein the spray amount of water is controlled so that the oxygen concentration in the receiver is 8% or less.