JP3114713B2 - Arc melting equipment and melting method for cold iron source - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc melting apparatus and a melting method for a cold iron source for melting a cold iron source such as iron scrap and direct reduced iron by an arc.

[0002]

2. Description of the Related Art In recent years, due to resource and environmental issues, processes for melting steel scrap with a large amount of generation using an arc furnace have been increasing. In such an arc furnace, since a large amount of power is consumed for melting the scrap, a method has been proposed in which the scrap is melted while preheating the scrap with exhaust gas generated from the furnace during the melting, thereby reducing the required power as much as possible.

For example, (1) a method in which a horizontal preheater is connected to an arc furnace, exhaust gas from the arc furnace is introduced into the preheater to preheat the scrap, and the preheated scrap is continuously supplied to the arc furnace. And (2) a method in which scrap preheated in the shaft pre-tropical zone by exhaust gas from the arc furnace is continuously supplied to the arc furnace by pushers provided in two stages (a strategy of the ordinary steel electric furnace industry,
P77 and P80; Iron and Steel Institute of Japan, November 1, 1994
4th).

[0004] (3) Two scrap preheating chambers are provided just above the arc furnace, the scrap in the chamber is preheated by exhaust gas generated from the arc furnace, and a stopper called a finger is opened to convert the scrap into the arc furnace. A supply type is also known (Electroheat, No. 82, 1995, P56).

[0005] Further, there is also a method (4) in which a rotary kiln and a shaft type pre-tropical are connected to an arc furnace, scrap is supplied from the shaft to the kiln by a pusher, and further, the scrap is continuously supplied to the arc furnace by the kiln. Kaihei 6
No. 122234).

Further, (5) a shaft-shaped pre-tropical zone is directly connected to a part of the furnace lid of the arc furnace, and one charge of scrap is supplied into the arc furnace and the shaft.
An electrode inserted from the side wall of the furnace while melting the scrap (Japanese Patent Publication No. 6-46145) and (6) a shaft-shaped arc furnace, wherein the scrap for one charge in the shaft is preheated by the exhaust gas. Are known to be dissolved.

[0007] In the arc furnace of the type in which the scrap is preheated by the exhaust gas as described above, the target is an electric power unit of about 250 to 270 kWh / t at a low value.

[0008]

However, the above-mentioned facilities (1) to (6) for preheating scrap with exhaust gas generated from an arc furnace have the following disadvantages.

In the facilities (1) to (4), in order to supply the scrap into the arc furnace, a device for transporting and supplying scrap such as a vibrating conveyor, a pusher, a kiln or a finger is required. There is a limit to the preheating temperature when preheating scrap with exhaust gas from the furnace. That is, when trying to preheat to a high temperature and increasing the amount of oxygen added to the furnace to increase the calorific value of the exhaust gas, hardware problems such as thermal deformation of the above-described apparatus are inevitable. In addition, when preheating to a high temperature, there is a problem in that fusion occurs locally and it becomes impossible to convey and supply scrap, and the preheating temperature is limited.

On the other hand, in the equipments of (5) and (6), since the scrap is charged in advance in the arc furnace or the shaft directly connected to the arc furnace and the arc furnace,
There is no need for the above-described device for scrap transport and supply, and therefore, the above-mentioned problems do not occur. However, in these facilities, the scrap in the arc furnace and the shaft is completely melted for each charge, and the molten steel in the furnace is tapped without leaving any scrap in the furnace and the shaft. Due to the inability to preheat, it is not sufficient in terms of effective utilization of exhaust gas.

The present invention has been made in view of such circumstances, and does not particularly require a device for transporting and supplying a cold iron source to a melting chamber, and also preheats a cold iron source for the next charge. It is possible to provide an extremely high-efficiency arc melting facility for a cold iron source, which cannot be achieved by a melting facility that preheats scrap by using conventional exhaust gas, and more specifically, has a specific power consumption of less than 250 kWh / t. An object of the present invention is to provide an arc melting facility for a cold iron source.

[0012]

Means for Solving the Problems To solve the above problems, a first invention is to provide a melting chamber for melting a cold iron source, and a melting chamber for melting a cold iron source.
Arc electrode for melting the cold iron source in the melting chamber and a cold iron source
Means for supplying a cold iron source continuously or intermittently;
A tapping section protruding from the melting chamber and having a tap hole;
Tilting means for tilting the melting chamber toward the tapping section, and
Arc of cold iron source melts cold iron source in melting chamber by arc
A melting apparatus, wherein the cold iron source is connected to the melting chamber during melting.
Is supplied from one side to the other side, and the tapping part is
It is provided in a direction different from the supply direction of the cold iron source
To provide the arc melting equipment of cold iron source and wherein a call.

In a second aspect based on the first aspect, the cold iron
The source supply means is a state in which a cold iron source is always present in the melting chamber.
Characterized by supplying a cold iron source to maintain the condition
Provide melting equipment.

[0014] A third invention is a dissolving method for dissolving a cold iron source.
Preheating the cold iron source, which is directly connected to the
A heat shaft and an arm for melting the cold iron source in the melting chamber
Electrode and cold iron source are continuously present in the melting chamber and preheating shaft.
Continuous cold iron source to preheat shaft to maintain
Or a cold iron source supply means for intermittently supplying, and the melting chamber
A tapping section protruding from
Tilting means for tilting toward the hot water outlet side,
Arc melting equipment for cold iron source that melts cold iron source by arc
Wherein the cold iron source in the preheating shaft is
The preheating shaft of the melting chamber is provided from one side to the other
And the tapping section is supplied with the cold iron source.
An arc melting facility for a cold iron source is provided, which is provided in a direction different from a supply direction .

[0015] A fourth invention is a dissolving method for dissolving a cold iron source.
Preheating the cold iron source, which is directly connected to the
A heat shaft and an arm for melting the cold iron source in the melting chamber
Electrode and cold iron source are continuously present in the melting chamber and preheating shaft.
Continuous cold iron source to preheat shaft to maintain
Or a cold iron source supply means for intermittently supplying, and the melting chamber
A tapping section protruding from
Tilting means for tilting toward the hot water outlet side,
Arc melting equipment for cold iron source that melts cold iron source by arc
Wherein the cold iron source in the preheating shaft is
The preheating shaft of the melting chamber is provided from one side to the other
And the tapping section is supplied with the cold iron source.
The dissolving chamber is provided in a direction different from the feeding direction, and
The part where the heat shaft is provided and the part where the tapping part is provided
When the melting chamber is tilted, the cold iron source
Space so that it can be prevented from
It has to provide a arc melting equipment cold iron source, characterized in that.

[0016] The fifth invention, in the fourth invention, in the melting chamber, spaced apart from the preheating shaft is provided part and tapping portion is provided partially, the spacing distance is dissolved from the preheating shaft An arc melting facility for a cold iron source, characterized in that the cold iron source extends at a repose angle over a room and is longer than a spreading distance from a preheating shaft .

The sixth invention is the first invention to the fifth invention.
The tapping section is in the supply direction of the cold iron source.
To provide an arc melting facility for a cold iron source, wherein the arc melting facility is provided in a direction perpendicular to the arc.

According to a seventh aspect, there is provided any one of the first to sixth aspects.
When the melting chamber is tilted at the time of tapping,
Move the arc electrode following the molten iron moving
An arc of a cold iron source, further comprising moving means.
Provide melting equipment. The eighth invention relates to the first invention to the eighth invention.
In any one of the seven inventions, the other provided in the tapping section
Arc melting equipment for a cold iron source, further comprising:

The ninth invention is the first invention to the eighth invention.
In the meantime, the melting chamber and
More than 50% of the cold iron source for one charge remains on the preheating shaft
Arc melting equipment for cold iron sources
provide. The tenth invention is any of the first to ninth inventions.
In some cases, the molten iron in the melting chamber is supplemented with coke or the like.
Auxiliary heat source supply means for supplying an auxiliary heat source;
Oxygen supply means for supplying oxygen to the molten iron.
An arc melting facility for a cold iron source is provided.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention,
The supply amount of oxygen from the oxygen supply means is 25 Nm ³ / t or more
Providing an arc melting equipment cold iron source, characterized in that it. The twelfth invention is any of the first to eleventh inventions
In this, a part or all of the bottom of the melting chamber is
The bottom of the portion of the melting chamber where the tapping portion is provided
From the deepest position to the direction in which the furnace tilts.
Cold iron source characterized by being inclined to be high
Arc melting equipment .

The thirteenth invention is the first to twelfth inventions
The cold iron source using any of the arc melting equipment
The cold iron source is always present in the melting chamber.
That is, when a predetermined amount of molten iron is generated, the melting chamber is placed on the tapping side.
To the molten iron by the arc,
The feature is that hot water is supplied while the source is present
To provide an arc melting method for a cold iron source .

The applicant of the present invention has a melting chamber and a preheating shaft directly connected to the melting chamber, and does not particularly require a device for transporting and supplying a cold iron source to the melting chamber. Since the cold iron source in the melting chamber is melted by the arc while continuously or intermittently supplying the cold iron source to the preheating shaft so as to keep the iron source continuously present in the melting chamber and the preheating shaft, cold iron source is present within and dissolution chamber preheating shaft when a possible pre-heating of the cold iron source follows the charge, arc capable of realizing the dissolution of extremely high efficiency of cold iron source of
Application for melting equipment (Japanese Patent Application No. 9-54260)
No.)

However , in this state, the molten iron and the cold iron source such as scrap are always coexisting in the melting chamber, that is, the molten metal is discharged while the cold iron source is immersed in the molten iron.
The temperature of the molten iron to be poured is low, and there is a possibility that the tapping may be hindered by the adhesion of solidified metal at the tap at the time of tapping.

In order to solve the problem that the tapping temperature is low while securing the above advantages, the present inventors set the temperature of the molten iron in the melting chamber in a state where a cold iron source is continuously provided in the preheating shaft and the melting chamber. As a result of intensive studies on the method of increasing the iron content, the superheat (ΔT) of the molten iron
And the contact area (S) between the molten iron and the cold iron source immersed in the molten iron was found to have the following relationship.

W∝ΔT · S ΔT∝W / S

Therefore, in order to increase the superheat (ΔT), it is necessary to reduce the contact area (S) between the molten iron and the cold iron source immersed in the molten iron when the melting rate, that is, the arc heating power is constant. It is valid.

For this reason, a method of tilting the melting chamber and discharging the molten iron to the tap hole side by using a tilting mechanism of the melting chamber used for tapping the molten iron to reduce the contact area between the molten iron and the cold iron source. However, in the melting equipment described in the embodiment of Japanese Patent Application No. 9-54260, since the tap hole is provided in the direction in which the cold iron source is supplied from the preheating shaft, when the melting chamber is tilted, The cold iron source flows in the tilting direction,
It is difficult to effectively reduce the contact area between the molten iron and the cold iron source.

[0028] In the present invention, Ru is provided a tapping unit in a direction different from the feed direction of Hiyatetsugen. This allows the melting chamber
When tilted toward the hot water outlet, the cold iron source flows in the tilting direction.
Is prevented. Further, the portion of the melting chamber where the preheating shaft is provided and the portion where the tapping section is provided can prevent the cold iron source from flowing out to the tap hole side when the melting chamber is tilted. , That is, the cold iron source is blocked by the wall between them. By so doing, when the melting chamber is tilted toward the tapping portion, the cold iron source is more effectively prevented from flowing in the tilting direction, and the contact area between the molten iron and the cold iron source is reduced. The size can be reliably reduced. Therefore, the superheat of the molten iron can be increased by heating the molten iron by the arc for a certain period of time after tilting, and while preventing the clogging of the tap hole due to the low temperature of the molten iron at the time of tapping, the extremely efficient cooling can be performed. An arc melting facility for an iron source can be realized .

In addition, in addition to the above, a part or the whole of the bottom of the melting chamber is set such that the bottom of the portion of the melting chamber where the tapping section is provided is the deepest position, and from that position in the direction in which the furnace tilts. by tilting to higher, when moving the molten iron by tilting the furnace in the direction of the tapping unit, and the cold iron source on the inclined swash surface, it can be further reduced contact area molten iron. Therefore, the superheat of the molten iron can be further increased.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing an arc melting facility according to one embodiment of the present invention,
2 is a plan view thereof, FIG. 3 is a sectional view taken along the line AA ′ of FIG. 1, and FIG. 4 is a sectional view taken along the line BB ′ of FIG.
The arc melting equipment includes a melting furnace 1 for arc melting a cold iron source, a preheating shaft 2 directly connected to an upper portion of one side 1a and extending upward, and an outlet provided in a melting chamber 1. And a steel part ( water tapping part ) 3.

As shown in FIG. 3, an exhaust portion 2a connected to the exhaust gas suction system is provided at the upper end of the preheating shaft 2. Iron scrap S as a cold iron source is charged into the melting furnace 1 and the preheating shaft 2.

A scrap loading bucket 4 is provided above the preheating shaft 2, and iron scrap S is loaded into the preheating shaft 2 from the bucket 4. Further, a carbon source, for example, coke may be charged into the preheating shaft 2 to prevent hanging on the shelf. In this case, the charging of the scrap S from the basket 4 is performed by continuously supplying the scrap S to the preheating shaft 2 so as to keep the scrap S continuously present in the melting chamber 1 and the preheating shaft 2 during operation. Or supply intermittently. At this time, the charging of the scrap S may be performed based on a recipe set in advance based on the operation results, or a sensor capable of detecting the amount of the scrap S in the preheating shaft 2 is provided. The input of the scrap S by the bucket 4 may be controlled by an appropriate control means based on the signal.

An openable / closable furnace lid 5 is provided on the upper part of the melting furnace 1, and an arc electrode 6 is inserted vertically from above the melting furnace 1 through the furnace lid 5. Further, a furnace bottom electrode 11 is provided at a position of the furnace bottom 10 of the melting furnace 1 facing the arc electrode 6. Then, the scrap 7 is formed by the arc 7 formed by the arc electrode 6.
Is melted to form molten steel 8. A slag 9 is formed on the molten steel 8, and the arc 7 is formed in the slag 9. The arc electrode 6 is supported by a support member 13 and can be tilted by a tilting mechanism 14.

The melting furnace 1 has two lances 12a,
12b is inserted with its tip facing the molten steel surface,
Oxygen is supplied from the lance 12a, and coke as an auxiliary heat source is injected from the lance 12b.

The scrap S in the preheating shaft 2 is supplied in a direction from the preheating shaft side 1a of the melting furnace 1 toward the opposite side 1b, and the tapping portion 3 is orthogonal to the supply direction of the scrap S. In the melting furnace 1 so as to face in the direction of the melting furnace 1. The melting furnace 1 can be tilted toward the tapping portion 3 by a tilting mechanism (not shown). Further, the portion of the melting furnace 1 where the preheating shaft 2 is provided and the portion where the tapping portion 3 is provided are separated by a distance a, and when the melting furnace 1 is tilted, the wall of that portion causes Scrap S is prevented from flowing out to the tapping portion 3 side. In this case, as shown in FIG. 3, it is preferable that the distance a is longer than the distance of the scrap S spreading at a repose angle from the preheating shaft 2 to the melting furnace 1. By doing so, it is possible to completely prevent the scrap S from flowing out to the tapping portion 3 when the melting furnace 1 is tilted.

A tap hole ( tap tap ) 15 is formed at the bottom near the tip of the tapping section 3 (see FIG. 4), and a vertically movable stopper 16 for opening and closing the tap tap 15 is provided.
Is provided. Further, a slag door 17 is provided on the side surface of the tip end of the tapping portion 3.

In melting the iron scrap in the melting equipment configured as described above, first, the iron scrap S is charged into the melting furnace 1 and the preheating shaft 2, and the iron scrap S is put into the melting furnace 1 and the preheating shaft 2. The state exists continuously.

In this state, an arc 7 is formed by the arc electrode 6 and the iron scrap S is melted. At this time, oxygen is supplied from the lance 12a to assist in dissolving the scrap. Then, when molten steel accumulates in the furnace, the lance 12
b, coke as an auxiliary heat source is injected into the slag and the operation proceeds to the slag forming operation.
Is buried in the slag 9 so that the arc 7 is formed in the slag 9. The coke as the auxiliary heat source contributes to the dissolution of the scrap S.

Exhaust gas generated by such scrap melting is discharged via the preheating shaft 2 and the exhaust part 2a, and the heat of the exhaust gas preheats the scrap S in the shaft 2. As the scrap S is melted in the melting furnace 1, the scrap of the preheating shaft 2 is sequentially supplied to the melting furnace 1, so that the upper end position of the scrap S in the preheating shaft 2 is lowered. In this case, the scrap S is continuously or intermittently supplied from the bucket 4 to the preheating shaft 2 so that the scrap S is kept in the melting chamber and the preheating shaft. As a result, a state in which a certain amount or more of scrap is always present in the melting furnace 1 and the preheating shaft 2 is maintained. At this time, the charging of the scrap S may be performed based on a recipe set in advance based on the operation results as described above, or a sensor capable of detecting the amount of the scrap S in the preheating shaft 2 is provided. The feeding of the scrap S by the bucket 4 may be controlled based on a signal from this sensor.

When the scrap S is melted, the melting furnace 1
Inside, the scrap S, which is a cold iron source, and the molten steel coexist, and the temperature of the molten steel is low, for example, 1540 to 1
There is only a slight superheat at 550 ° C. and a solidification temperature of molten steel of 1530 ° C., and if this is done as it is, inconveniences such as clogging of a tapping hole occur at the time of tapping. Therefore, in the present invention, before tapping, as shown in FIG. 5, the melting furnace 1 is tilted toward the tapping portion 3 to continue the arc heating. In this case, the tapping part 3 is protruded from the melting furnace 1 so as to face in a direction perpendicular to the direction in which the scrap S flows into the melting furnace 1, and the preheating shaft 2 of the melting furnace 1 is provided. The portion where the tapping portion 3 is provided is separated from the portion where the tapping portion 3 is provided by a distance a, and the wall of the portion prevents the scrap S from flowing to the tapping portion 3 side. The contact area between the molten steel flowing into the side and the scrap S can be reduced. Therefore, the superheat (ΔT) of the molten steel can be increased, and the problem that the temperature of the molten steel to be tapped is low can be avoided. Preheating of the scrap S extending in the angle of repose of the distance a over from the preheating shaft 2 in the melting furnace 1
By setting the length to be longer than the spreading distance from the shaft , the inflow of the scrap S into the tapping portion 3 can be almost completely prevented, and the temperature of the molten steel can be further increased.

When the melting furnace 1 is tilted, the arc electrode 6 comes to the position shown by the broken line in FIG. 5 and the arc is not effectively supplied. However, by tilting the arc electrode 6 by the tilting mechanism 14, the arc electrode 6 shown in FIG. The position becomes the solid line position, and the arc can be effectively supplied to the molten steel.

Instead of moving the arc electrode 6 in this manner, as shown in FIG. 6, another arc electrode 6 'is provided in the tapping portion 3, and when the melting furnace 1 is tilted, the arc electrode 6' By generating an arc from, the arc can be supplied effectively.

When the melting proceeds as described above and a predetermined amount of molten steel is accumulated in the furnace, the melting furnace 1 is tilted to reduce the contact area between the molten steel and the scrap, and the molten steel is heated by arc heating for a predetermined time. After the superheating, the melting furnace 1 is further tilted to stop the tapping hole 15 of the tapping section 3 while keeping the state in which the scrap S is continuously present in the melting furnace 1 and the melting shaft 2. 16 is raised to open the tapping port 15, and one charge of molten steel is tapped from the tapping port 15 to a ladle or the like.

When the scrap is melted in this manner, the preheating shaft 2 is not provided with a device for transporting and supplying the scrap such as a pusher or a finger. The amount of oxygen used can also be increased, and the exhaust gas temperature can be increased. Therefore, it becomes possible to preheat the scrap to a higher temperature than conventional melting equipment.

Further, the scrap S is supplied to the preheating shaft 2 so that the scrap S is always kept continuous with the melting furnace 1 and the preheating shaft 2, and molten steel for one charge or more is formed in the melting furnace 1. When tapping the steel, the scrap is continuously present in the melting furnace 1 and the preheating shaft 2, so that the scrap preheating efficiency by the exhaust gas is high.
In this case, 50 parts for one charge during melting and tapping.
By making the scrap of not less than% continuously exist in the melting furnace 1 and the preheating shaft 2, the preheating efficiency becomes extremely high.

From the viewpoint of efficiently dissolving scrap, it is desirable to use an auxiliary heat source such as coke. By injecting coke as an auxiliary heat source from the lance 12b and supplying oxygen from the lance 12a, CO gas is generated in the melting furnace 1 and can generate heat. In this case, it is preferable that the amount of supplied oxygen is 25 Nm ³ / t or more.
Thereby, the scrap can be more efficiently melted. More preferably, it is 40 Nm ³ / t. FIG.
Shows the basic unit of electric power when the basic unit of oxygen is set to 15 to 45 Nm ³ / t in the melting furnace in Examples described later. As shown in this figure, the power consumption decreases as the oxygen consumption increases. In particular, when the power consumption becomes 25 Nm ³ / t or more, the power consumption becomes an extremely low value of 200 kWh / t or less.
Further, when it becomes 40 Nm ³ / t or more, it becomes about 120 kWh / t or less, and further lower value.

As described above, according to the above-described embodiment, the temperature of the exhaust gas can be increased because no equipment such as a pusher or a finger is required, and the scrap S always exists continuously in the melting furnace 1 and the preheating shaft 2. Therefore, the dissolving efficiency of scrap is extremely high. Further, since the contact area between the scrap S, which is a cold iron source, and the molten steel generated by melting the scrap S can be reduced,
The molten steel can be superheated, and the problem that the temperature of the molten steel to be tapped is low can be solved.

Next, a second embodiment will be described with reference to FIGS. FIG. 8A is a plan view showing an arc melting facility according to a second embodiment of the present invention,
(B) is sectional drawing of XX 'of (a).

In this embodiment, as shown in FIG. 8, a part corresponding to the preheating shaft of the melting chamber and a part of the bottom of the part corresponding to the separation part are provided with the tapping part 3 of the melting chamber. The bottom of the portion 1b is the deepest position 1d, and an inclined portion 1c is formed so as to be higher from that position in the direction in which the furnace tilts.

As shown in FIG. 9 and FIG.
By tilting, the contact area between the scrap and the molten steel 8 changes from the hatched portion 8a in FIG. 9 to the hatched portion 8b in FIG. 10, and also in the present embodiment, by tilting the melting furnace,
The scrap is prevented from flowing in the tilting direction, and the contact area between the scrap and the molten steel 8 can be reduced,
Can be superheated. In this case, in the present embodiment, when the melting furnace 1 is tilted, as shown in the drawing, the contact area between the scrap and the molten steel 8 is significantly larger than in the case of the first embodiment due to the presence of the inclined portion 1c. Become smaller. Therefore, the superheat (ΔT) of the molten steel can be increased as compared with the first embodiment, and the problem that the temperature of the molten steel to be tapped is low can be more effectively avoided. After the overheating in this manner, similarly to the first embodiment, the melting furnace 1 is further tilted to keep the scrap S continuously present in the melting furnace 1 and the melting shaft 2 and the tapping section. The stopper 16 which closed the tapping port 15 of No. 3 is raised to open the tapping port 15, and one charge of molten steel is discharged from the tapping port 15 to a ladle or the like.

The structure of the arc melting equipment may be as shown in FIG. In the arc melting equipment of FIG. 11, the portion of the side wall of the melting furnace 1 immediately below the preheating shaft 2 is an inclined portion 18 inclined toward the bottom of the separated portion a. By providing the inclined portion 18 in this manner, the supply of the scrap S from the preheating shaft 2 to the separated portion a can be performed more smoothly, following the melting of the scrap S on the contact surface between the scrap S and the molten steel 8. it can.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above-described embodiment, the tapping portion 3 is provided so as to face in a direction orthogonal to the inflow direction of the scrap flowing from the preheating shaft side 1a of the melting furnace 1 toward the opposite side 1b, but is not limited thereto. Any direction other than the inflow direction of the scrap may be used. If the direction is other than the inflow direction of the scrap, the effect of preventing the scrap from flowing out to the tapping portion can be obtained. In addition, although an example in which molten steel was produced using scrap as a cold iron source was shown, the present invention is also applicable to other cold iron sources such as direct reduced iron, and is also applicable to equipment for producing molten iron in addition to molten steel. Needless to say, there is. In the above-described embodiment, an example in which the arc electrode is tilted in order to melt the scrap has been described. However, the present invention is not limited to the tilting, and other moving means may be used. Further, in the second embodiment, the case where the inclined portion is formed in a part of the bottom corresponding to the portion corresponding to the preheating shaft and the portion corresponding to the separated portion of the melting chamber has been described, but the entire bottom is formed as a slope. Department. In the above-described embodiment, an example in which molten steel is manufactured using scrap as a cold iron source has been described, but the present invention is also applicable to a facility for manufacturing hot metal using cold pig as a cold iron source.

[0053]

EXAMPLES (Example 1) Melting furnace (length: 8.5 m, width;
3 m, height 4 m) and a preheating shaft (3 mW × 3 mD) were directly connected to a melting furnace and a preheating shaft of a DC arc equipment as shown in FIGS. With a 28 inch graphite electrode,
An arc was formed with a maximum power supply capacity of 600 V and 100 kA, and the scrap was melted. A water-cooling lance is inserted from the working port provided on the furnace side wall, and 6000 Nm ³ /
The acid was fed in the amount of hr. When molten steel had accumulated in the furnace, coke was injected into the slag at 80 kg / min, and the slag forming operation was started, and the tip of the graphite electrode was buried in the forming slag. The voltage at this time was set to 400V. When the scrap in the preheating shaft descended due to the melting of the scrap in the melting furnace, the scrap was supplied from the scrap charging basket from the upper part of the preheating shaft, and the height of the scrap in the preheating shaft was maintained at a constant height. .

As described above, the melting is advanced in a state where the scrap is continuously present in the melting furnace and the preheating shaft, and when the molten steel is sufficiently generated, the melting furnace is tilted 15 degrees to the tapping portion side. When the molten steel is superheated by reducing the contact area between the molten steel and the scrap, and when a total of 180 tons of molten steel is generated in the melting furnace, the melting furnace is further tilted, leaving 60 tons in the furnace and one charge. 120 minutes
Tons of molten steel were tapped from a tapping hole into a ladle. The temperature of the molten steel at the time of tapping was 1575 ° C. C concentration in molten steel is 0.1
%Met.

After tapping of 120 tons, the melting furnace was returned to its original state, slag forming operation was performed while performing acid feeding and coke injection, and melting was continued. When sufficient molten steel was generated, the melting furnace was tilted again to remove molten steel. Superheated, 12 when the amount of molten steel in the melting furnace reached 180 tons again
The process of tapping 0 tons was repeated. On average tap-t
In about 40 minutes of ap, 120 tons of molten steel were obtained. An energy consumption of 175 kWh / t was obtained with an oxygen amount of 33 Nm ³ / t and a coke consumption of 26 kg / t.

The 120 tons of molten steel that was tapped was taken from a ladle furnace (L
F), the temperature was raised to 1620 ° C., and 175 was obtained by continuous casting.
A × 175 mm billet was manufactured. The average power consumption of LF was 45 kW / t on average. On the other hand, a power source unit was similarly obtained for a comparative example (similar to the prior art (5)) in which the same apparatus was used to continuously melt scrap one charge at a time without continuously supplying scrap.

Table 1 shows the results. As shown in Table 1, the amount of oxygen used was almost the same, and the continuously supplied Example 1 had a power source unit lower by about 140 kWh / t than the comparative example. However, the power consumption was as low as about 125 kWh / t. In addition, the power consumption per unit of the present invention is 50 kWh / t or more, and the power consumption per unit required before reaching LF is lower than that of the reported examples of other processes shown in the prior art. It was confirmed that the preheating efficiency of the scrap was very high.

(Example 2) In the above melting furnace, melting was carried out in the same manner as in Example 1 except that the amount of oxygen was 45 Nm ³ / t and the basic unit of coke was 36 kg / t. Table 1 also shows the results. The power consumption at this time is extremely low at 135 kW, and molten steel having an average temperature of 1575 ° C. is about 3 tap-tap.
Obtained in 7 minutes.

Example 3 Melting furnace (length: 8.5 m,
Width: 3m, height: 4m) and preheating shaft (3mW x 3m)
D, a half of the bottom surface of the portion corresponding to the preheating shaft and the portion corresponding to the separation portion of the melting furnace as shown in FIGS. 8, 9 and 10 have an inclined surface inclined at, for example, 15 degrees. Using a melting furnace and a preheating shaft of a DC arc facility, melting was performed under the same conditions as in Example 1 above.

As a result, as shown in Table 1, the tapping temperature at this time was 1600 ° C., which was higher than Examples 1 and 2. In addition, the oxygen amount is 33 Nm ³ / t, and the coke intensity is 26.
The power consumption per kg / t was 188 kWh / t, and the power consumption per unit of LF was 30 kWh / t on average.

Example 4 Melting was carried out in the same manner as in Example 3 except that the amount of oxygen was 45 Nm ³ / t and the basic unit of coke was 36 kg / t. Table 1 also shows the results. The power consumption at this time is extremely low at 148 kW, and molten steel having an average temperature of 1600 ° C. has a tap-tap
Obtained in 7 minutes.

[0062]

[Table 1]

[0063]

As described above, according to the present invention,
Since a cold iron source such as scrap is melted using an arc melting facility having a melting chamber and a preheating shaft directly connected to the melting chamber, a device for transporting and supplying the cold iron source to the melting chamber is not particularly required. . Also, while supplying the cold iron source to the preheating shaft so as to maintain the state where the cold iron source is continuously present in the melting chamber and the preheating shaft, the cold iron source in the melting chamber is melted by the arc, and the molten iron is supplied to the melting chamber and the preheating shaft. Since the molten iron is poured in a state where the cold iron source is present, it is also possible to preheat the cold iron source of the next charge, and it is possible to realize the extremely high efficiency melting of the cold iron source. In addition, since the contact area between the cold iron source and the molten metal generated by melting it can be reduced, the molten iron can be superheated, and the problem that the temperature of the molten iron discharged is low is solved. Can be. Also,
Further, part or all of the bottom of the part corresponding to the preheating shaft and the part corresponding to the separation part of the melting chamber, the bottom of the part provided with the tapping part in the melting chamber is the deepest position,
By configuring the inclined portion inclined so as to become higher from the position toward the method of tilting the furnace, the contact area between the cold iron source and the molten iron is significantly increased as compared with a case where the inclined portion is not provided at the bottom of the melting chamber. The problem that the temperature of the molten iron to be discharged is low can be more effectively avoided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an arc melting facility according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arc melting facility according to one embodiment of the present invention.

FIG. 3 is a sectional view taken along the line A-A ′ in FIG. 1;

FIG. 4 is a sectional view taken along line B-B ′ of FIG. 1;

FIG. 5 is a cross-sectional view showing a state where the melting furnace in the arc melting equipment according to the embodiment of the present invention is tilted.

FIG. 6 is a sectional view showing a modification of the arc melting equipment shown in FIGS. 1 to 5;

FIG. 7 is a diagram showing the relationship between the oxygen consumption rate and the power consumption rate when operating using the apparatus of the present invention.

FIG. 8 is a plan view and a cross-sectional view showing an arc melting facility having a slope at a bottom according to a second embodiment of the present invention.

FIG. 9 is a sectional view showing an arc melting facility according to a second embodiment.

FIG. 10 is a cross-sectional view showing a state where the arc melting equipment according to the second embodiment is tilted.

FIG. 11 is a sectional view showing a modification of the arc melting equipment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Melting furnace 2 ... Preheating shaft 3 ... Tapping part 4 ... Scrap charging bucket 6 ... Electrode 7 ... Arc 8 ... Molten steel 9 ... Slag 15 ... Tapping outlet S ... Iron scrap

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F27D 13/00 F27B 3/08 F27D 17/00 104

Claims (13)

(57) [Claims] 1. A melting chamber for melting a cold iron source, an arc electrode for melting the cold iron source in the melting chamber, and a cold iron source supplying means for continuously or intermittently supplying the cold iron source. A tapping section protruding from the melting chamber and having a tap hole, and a tilting means for tilting the melting chamber toward the tapping section, and a cold iron source for melting a cold iron source in the melting chamber by an arc. An arc melting facility, wherein the cold iron source is supplied from one side of the melting chamber to the other side during melting, and the tapping unit is provided in a direction different from a supply direction of the cold iron source. Arc melting equipment for cold iron sources. 2. The arc melting equipment according to claim 1, wherein the cold iron source supply means supplies the cold iron source such that the cold iron source always exists in the melting chamber. 3. A melting chamber for melting a cold iron source, a preheating shaft directly connected to an upper portion of one side thereof for preheating the cold iron source, and an arc electrode for melting the cold iron source in the melting chamber. ,
Cold iron source supply means for continuously or intermittently supplying the cold iron source to the preheating shaft so as to maintain a state in which the cold iron source is continuously present in the melting chamber and the preheating shaft; An arc melting facility for a cold iron source, comprising: a tapping section having a tapping port; and a tilting unit for tilting the melting chamber toward the tapping section, and melting a cold iron source in the melting chamber by an arc. The cold iron source in the shaft is supplied from one side where the preheating shaft of the melting chamber is provided to the other side during melting, and the tapping part is in a direction different from the supply direction of the cold iron source. Arc melting equipment for cold iron sources, which is provided. 4. A melting chamber for melting a cold iron source, a preheating shaft directly connected to an upper portion of one side thereof for preheating the cold iron source, and an arc electrode for melting the cold iron source in the melting chamber. ,
Cold iron source supply means for continuously or intermittently supplying the cold iron source to the preheating shaft so as to maintain a state in which the cold iron source is continuously present in the melting chamber and the preheating shaft; An arc melting facility for a cold iron source, comprising: a tapping section having a tapping port; and a tilting unit for tilting the melting chamber toward the tapping section, and melting a cold iron source in the melting chamber by an arc. The cold iron source in the shaft is supplied from one side where the preheating shaft of the melting chamber is provided to the other side during melting, and the tapping part is in a direction different from the supply direction of the cold iron source. Provided, and between the portion where the preheating shaft of the melting chamber is provided and the portion where the tapping portion is provided,
An arc melting facility for a cold iron source, comprising a separating portion so as to prevent the cold iron source from flowing into the tapping portion when the melting chamber is tilted. In wherein said melting chamber, Contact and separated from the preheating shaft is provided part and tapping portion is provided partially
The distance between the preheating shaft and the preheating shaft of the cold iron source, which extends at an angle of repose from the preheating shaft to the melting chamber.
The arc melting equipment of a cold iron source according to claim 4, wherein the distance is longer than the distance . 6. The hot water supply section according to claim 1, wherein the hot water supply section is provided in a direction orthogonal to a supply direction of the cold iron source. Arc melting equipment for cold iron sources. 7. The apparatus according to claim 1, further comprising a moving means for moving the arc electrode following the molten iron moving in the melting chamber when the melting chamber is tilted at the time of tapping. Item 2. An arc melting facility for a cold iron source according to item 1. 8. The arc melting facility for a cold iron source according to claim 1, further comprising another arc electrode provided in the tapping section. 9. The method according to claim 1, wherein at least 50% or more of the cold iron source for one charge remains in the melting chamber and the preheating shaft during melting and at the time of tapping. 2. An arc melting facility for a cold iron source according to claim 1. 10. The apparatus according to claim 1, further comprising: an auxiliary heat source supplying means for supplying an auxiliary heat source such as coke to the molten iron in the melting chamber; and an oxygen supplying means for supplying oxygen to the molten iron in the melting chamber. An arc melting facility for a cold iron source according to any one of claims 9 to 9. 11. The method according to claim 1, wherein the supply amount of oxygen from the oxygen supply means is 25 Nm ³ / t or more.
0. An arc melting facility for a cold iron source according to 0. 12. A part or all of a bottom of a part corresponding to the preheating shaft and a part corresponding to the separation part of the melting chamber, a bottom of a part of the melting chamber where the tapping part is provided is a deepest part. The arc melting equipment of a cold iron source according to any one of claims 1 to 11, wherein the arc melting is performed so as to be higher in a direction in which the furnace tilts from the position. 13. In melting the cold iron source using the arc melting equipment according to any one of claims 1 to 12,
Keeping the state where the cold iron source is always present in the melting chamber, when a predetermined amount of molten iron is generated, tilt the melting chamber to the tapping side, heat the molten iron by the arc, and the cold iron source is present in the melting chamber. An arc melting method for a cold iron source, wherein the hot water is supplied while maintaining the state.