JPH0992461A - Method for melting and smelting metal in electric steelmaking furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool graphite electrodes by spraying of a coolant without generating hydrogen gas or the like through water gas reactions inside an electric-arc furnace by greatly reducing original electrode units through the minimizing of the oxidation wear of the graphite electrodes. SOLUTION: A coolant 2 is sprayed toward the outer peripheries of the line of graphite electrodes which comprises graphite electrodes 1 connected to one another via nipples, while the coolant 2 ejected is inclined downward by a downward inclination angle of 10 deg. to 35 deg. to a horizontal level. In this case, the amount of the coolant 2 sprayed is 0.8 to 35 liter per minute.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melting and refining metals in an electric steelmaking furnace. More specifically, in an electric steelmaking furnace such as an arc electric furnace, graphite electrodes sequentially connected through nipples are used. Applying electric current to melt metal such as steelmaking
When refining, above the furnace lid of the arc electric furnace,
Cooling liquid such as cooling water is jetted to the outer peripheral surface of the graphite electrode by inclining downward with a downward inclination angle, and at the same time, keeping the injection amount of the cooling liquid within an appropriate range, and Determine the optimum value according to the diameter of the graphite electrode to be cooled within the range, keep the amount of cooling water sprayed to this optimum value, spray the cooling water to cool, and oxidize the graphite electrode during melting and refining. The consumption of electricity is kept to a minimum and the basic unit of electrode is greatly reduced.
The present invention relates to a method for melting and refining a metal in an arc electric furnace without generating hydrogen gas due to an aqueous reaction.

[0002]

2. Description of the Related Art Conventionally, in the melting and refining of metals in an electric arc furnace such as steelmaking, in addition to the reduction in the cost of electric energy, the consumption of oxidation at the tip and outer peripheral surface of the graphite electrode is suppressed, Therefore, it is desired to reduce the electrode unit consumption. It has been proposed to cool the graphite electrode as a means for suppressing this oxidative consumption, and as one of the cooling methods, in the graphite electrode rows that are sequentially connected, the graphite electrode above the furnace lid of the electric arc furnace There has been proposed a method of cooling water by a water-cooled non-consumable electrode having a structure in which cooling water flows.

That is, the non-consumable electrode has a structure in which it is water-cooled by cooling water flowing therein, but this electrode is not limited to cooling the graphite electrode connected to the lower end of the non-consumable electrode through a nipple. During the refining operation, the oxidation consumption of only the graphite electrode connected to the lower end of the non-consumable electrode is reduced.

For example, US Pat. No. 4,416.014,
The water-cooled non-consumable electrode described in each specification of No. 4.417.344 and No. 4.451.926 is composed of a hollow cylinder made of aluminum, and cooling water is introduced into the hollow cylinder and introduced. The cooling water successively cools the graphite electrode from the connection end face connected to the lower end of the non-consumable electrode in the hollow cylinder in the length direction of the graphite electrode.

The water-cooled non-consumable electrodes described in JP-A-60-501879 and JP-A-60-501880 are composed of a tubular body made of graphite and have a central hole. Cooling water is introduced into the inside, and the wall surface of the tubular body and the graphite electrode connected thereto are cooled from the connecting end face by this cooling water.

When the non-consumable electrode is cooled in this way, the graphite electrode connected to the lower end of the non-consumable electrode is directly cooled, and the oxidation and consumption of the graphite electrode is directly suppressed.

However, even if the graphite electrode connected to the lower end of the non-consumable electrode is cooled, what is involved in cooling is limited to the connection end face between the graphite electrode and the non-consumable electrode, and the cooling efficiency is high. Extremely low.

Above all, the thermal conductivity of graphite itself is 10
The graphite electrode, which falls below 0 ° C and participates in refining, is the electrode that is further connected below the electrode connected to the non-consumable electrode and the lower part of the electrode connected to the non-consumable electrode. It is difficult to cool such a graphite electrode.

When removing the graphite electrode from the non-consumable electrode, the graphite electrode is moved off-line from the arc electric furnace to remove the used graphite electrode from the nipple, and when necessary, the nipple is also removed from the non-consumable electrode.

When connecting a new graphite electrode, a nipple is attached to the non-consumable electrode and a new graphite electrode is attached to this nipple.

Therefore, when the graphite electrode connected to the lower portion by the water-cooled non-consumable electrode is cooled, the graphite electrode is transferred offline for replacement, and heavy muscle labor is removed and connection work is performed there. Then, the work becomes extremely complicated. If the graphite electrode is repeatedly removed and connected, the threads of the graphite electrode, the non-consumable electrode, the nipple, etc. may be deformed, crushed or damaged, resulting in poor connection or increase in electrical resistance, thus hindering the operation.

[0012] From this point,
In the publication, in order to cool the graphite electrode connected through the nipple, without using a water-cooled non-consumable electrode, the graphite electrode surface protruding upward from the furnace lid of the arc electric furnace is used. A cooling device for spraying and cooling cooling water is described.

As shown in FIG. 4, this cooling device has a furnace lid 1
A graphite electrode array is vertically inserted through the column 1. In the graphite electrode array, the graphite electrodes are sequentially connected to the lower part of the graphite electrode 12 via a nipple, and in one graphite electrode array, the lower graphite electrode, that is, the graphite electrode below the furnace lid 11 is arced. It is in the electric furnace and is involved in the refining of steel making in the arc electric furnace. Above the furnace lid 11, the upper graphite electrode 12 is held by the electrode holder 13, and on the lower surface of the electrode holder 13, an annular cooling pipe 14 that surrounds the outer periphery of the upper graphite electrode 12 is provided. A plurality of vertical pipes 15 are projected downward from the nozzle 1, and the nozzles 1 directed to the surface of the graphite electrode 12 are provided on the inner surface of each vertical pipe 15.
6 are provided. Therefore, the cooling water supplied to the annular cooling pipe 14 descends along each vertical pipe 15, and the cooling water is sprayed from each nozzle 16 on the inner surface to the outer peripheral surface of the upper graphite electrode 12 to be cooled.

However, in the cooling device shown in FIG. 4, the cooling water is jetted from each nozzle 16 in a horizontal level or in a direction parallel to the horizontal level. For this reason, the cooling water is
When it collides with the outer peripheral surface, a considerable amount of it is reflected and scattered, and the scattered cooling water is large, and the electrode holder 13 and the furnace lid 11 are severely contaminated and damaged, making it difficult to put them into practical use. In particular, furnace lids are rarely made of expensive high-alumina refractory materials, and because they are made of refractory materials such as chamotte, contamination and wear are severe.

Further, the cooling water 16 which has collided is almost reflected and hardly descends along the graphite electrode. Therefore, the graphite electrode to be cooled is limited to the graphite electrode with which the cooling water collides, and unless the amount of cooling water used is abnormally increased, the lower graphite electrode involved in refining and the part involved in refining are also cooled. It cannot be done, and it is extremely uneconomical.

It is possible to increase the cooling effect by increasing the amount of cooling water used. However, as the amount of cooling water increases, the amount of scattered cooling water increases, and the cooling water easily enters the arc electric furnace as it is, which affects the reaction in the furnace. Among them, in the steel making of steel types that are not susceptible to hydrogen embrittlement, hydrogen gas generated by an aqueous reaction in the furnace is likely to enter molten steel. Therefore, in the method of Fig. 4, the graphite electrode itself must be cooled during operation. Is considered impossible.

Further, a large number of vertical pipes 15 project downward from the cooling pipe 4, and the projecting length thereof is extremely long. For this reason, when the cooling device is removed during electrode replacement, the long vertical pipe 15 becomes an obstacle, and electrode replacement becomes extremely troublesome.

Further, since the electromagnetic force is shielded by the cooling pipe 4, a considerable part of the current flowing through the graphite electrode 12 is cut off, which causes a great hindrance to the operation.

Further, when a cooling liquid such as cooling water is sprayed with a downward inclination to the graphite electrode, there are the following problems in relation to the spray amount of the cooling liquid.

That is, when the cooling liquid is sprayed on the outer peripheral surface of the graphite electrode, if the spraying amount of the cooling liquid is not within the proper range, a part of the cooling liquid will be scattered, and it will be as it is inside the arc electric furnace. to go into. Unlike the cooling water that flows along the surface of the graphite electrode, the cooling water that has entered inside produces hydrogen by a water-gas reaction when placed under high temperature conditions in an arc electric furnace, and this hydrogen is generated. Enter molten steel. The entry of hydrogen causes hydrogen embrittlement, which is a concern depending on the steel type. For this reason, the operation of spraying the cooling liquid on the graphite electrode has not been carried out for steel making of steel types that are strongly required toughness, etc.
The cooling device shown in Japanese Utility Model Publication No. 59-23357 is also proposed, but it is not actually used.

Further, prevention of oxidation and consumption, reduction of electrode unit consumption,
Although it is preferable to cool the graphite electrode by spraying a cooling liquid from the viewpoint of reducing the power consumption, if the degree of cooling is excessive, the graphite electrode is overcooled and the graphite electrode is energized. If the electrodes are not heated, refining reactions such as steelmaking will be impaired. For this reason, when supercooling is performed, only the amount of supercooling is heated, which in turn raises the electric power consumption rate and the electrode consumption rate, resulting in a significant cost increase.

[0022]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks. Specifically, in an electric steelmaking furnace such as an arc electric furnace, graphite electrode arrays which are sequentially connected through nipples are used. The cooling liquid is sprayed on the graphite electrode on the upper part of this, and in spraying this cooling water, the cooling liquid is sprayed at a predetermined inclination angle downward from the horizontal level, while the spray amount or injection amount of the cooling liquid is adjusted. We propose a metal melting and refining method that keeps the amount within a predetermined appropriate range and obtains the optimum spray amount within this appropriate range.

[0023]

That is, according to the method of the present invention, a graphite electrode array in which graphite electrodes are sequentially connected through a nipple is energized, and graphite of the graphite electrode array is provided above a furnace lid of an electric steelmaking furnace. Inclining downward with a downward inclination angle in the range of 10 ° to 35 ° with respect to the horizontal level toward the outer periphery of the electrode, the cooling liquid is jetted and sprayed to cool the graphite electrode array, while When the metal is arc-melted and refined, the cooling liquid is sprayed at a rate of 0.8 to 35 liters / minute.

In other words, in the method of the present invention, when the cooling liquid is sprayed and cooled on the outer peripheral surface of the graphite electrodes sequentially connected through the nipple, the cooling liquid has a predetermined inclination with respect to the horizontal level. While spraying with an angle and tilted downward, the spray amount of the cooling liquid is adjusted to an optimum spray amount in accordance with the diameter of the graphite electrode within an appropriate range. Therefore, almost all of the sprayed cooling liquid descends along the outer peripheral surface of the graphite electrode while contacting the outer peripheral surface of the graphite electrode, and a part of the cooling liquid evaporates while the cooling liquid is inside the arc electric furnace. It reaches the graphite electrode and is cooled to the tip of the graphite electrode array. Since the spray amount of the cooling water is adjusted according to the graphite electrode, the cooling does not become supercooling, and the cooling is performed well, and the power consumption rate and the electrode consumption rate are greatly reduced.

Also in the arc electric furnace, the invading cooling liquid always flows along and contacts the outer peripheral surface of the graphite electrode. For this reason, the invading cooling liquid is almost evaporated and scattered during the descent, and the water-gas reaction does not occur.

When the cooling liquid contains an oxidation resistant agent, when the cooling liquid descends along the outer peripheral surface of the graphite electrode, the oxidation resistant agent contained therein adheres and is formed by this adhesion. The oxidation resistant coating effectively prevents the graphite electrode from being consumed by oxidation.

Further, the spray amount of the cooling liquid is within the proper range. For this reason, even if a part of the cooling liquid enters the arc electric furnace, most of the cooling liquid is scattered in the middle of the furnace, no water gas reaction occurs in the furnace, and no hydrogen gas is generated. From that point, when refining in this way, hydrogen and the like are not mixed in the molten steel, and it is possible to easily refine even the steel type having a problem of hydrogen embrittlement.

The structure and operation of these means will be described below in detail with reference to the drawings.

FIG. 1 is an explanatory view showing an example of refining a metal while spraying a cooling liquid on a graphite electrode to cool it by the method of the present invention.

FIG. 2 is an explanatory view showing a part of the annular cooling pipe shown in FIG. 1 by cutting.

FIG. 3 is an enlarged view of a part of the annular cooling pipe shown in FIG.

First, in FIGS. 1 and 2, reference numeral 1 indicates a graphite electrode, and the graphite electrodes 1 are sequentially connected via a nipple to form a graphite electrode array. In the graphite electrode array,
The upper graphite electrode 1 above the furnace lid is held by an electrode holder (not shown).

The graphite electrode array is inserted through the furnace lid of an arc electric furnace (not shown), and the graphite electrodes involved in refining are used to arc heat the metal and other materials in the arc electric furnace to produce steel. Refining is performed.

Further, in the arc electric furnace, when heating is performed by a three-phase AC voltage, they are sequentially connected via a nipple on a circle circle having a predetermined radius centered on the center of the arc electric furnace. Three graphite electrode rows are arranged.

When DC heating is used instead of AC heating, one graphite electrode array is arranged and this graphite electrode array is DC heated.

Therefore, in one graphite electrode array, a cooling liquid 2 such as cooling water is provided on the outer peripheral surface of the graphite electrode 1 above the furnace lid downwardly with respect to the horizontal level from 10 ° to 35 °. The spray angle is set to an angle and sprayed, and the spray amount of the cooling liquid 2 at this time is kept in the range of 0.8 to 35 liters / minute, and is optimal in accordance with the diameter of the graphite electrode to be cooled. The amount is determined, and the optimum amount of cooling water is sprayed on the outer peripheral surface of the graphite electrode while inclining downward.

That is, with respect to the spray amount of the cooling liquid, the spray amount in the optimum range is obtained in combination with the diameter of the graphite electrode to be cooled. Further, within the optimum range corresponding to each electrode diameter, the optimum amount of the cooling liquid is obtained mainly from the relationship with the electrode basic unit, and the cooling liquid is sprayed to reach this amount.

The optimum amount of this cooling liquid is, as already shown, from the relation with the diameter of the graphite electrode to be cooled, by the way, when the electrode diameter is 400 mm ± 20 mm, the cooling liquid is 6 to 9 liters. Spray at a rate of / minute.

When the diameter of the graphite electrode to be cooled becomes large and becomes large, that is, the diameter is 450 mm ± 20 mm.
In the case of, spray at a rate of 8 to 12 liters / minute.
When the diameter of the graphite electrode to be cooled is 500 mm ± 30 mm, the cooling liquid is sprayed at a rate of 10 to 14 l / min.

The diameter of the graphite electrode to be cooled is 550
In the case of mm ± 20 mm, the cooling liquid is sprayed at a rate of 12 to 17 liters / minute.

The diameter of the graphite electrode to be cooled is 600
In the case of mm ± 30 mm, spray at a rate of 14 to 20 liters / minute.

The diameter of the graphite electrode to be cooled is 650.
In the case of mm ± 20 mm, the cooling liquid is sprayed at a rate of 17 to 24 l / min.

The diameter of the graphite electrode to be cooled is 700
In the case of mm ± 30 mm, the cooling liquid is sprayed at a rate of 20 to 28 liters / minute.

The diameter of the graphite electrode to be cooled is 760
In the case of mm ± 30 mm, spray at a rate of 23 to 32 liters / minute.

Within this proper range, the electrode unit (kg / t) is lower than that of the conventional example (when cooled by the consumable electrode).
Is reduced by about 14 to 19%, and electric power consumption rate (kwh / t)
Is also reduced by about 3-5%.

The cooling liquid can be sprayed by any method under the above conditions, but the cooling liquid can be sprayed using the annular cooling pipe 3 as follows. .

As shown in FIG. 1, an annular cooling pipe 3 is arranged around the graphite electrode 1 to which the cooling liquid is sprayed, and the cooling liquid is fed into the annular cooling pipe 3. The spray nozzle 4 is attached to the inner surface of the annular cooling pipe 3 while inclining downward, and the cooling liquid is sprayed while inclining downward from the spray nozzle 4 and sprayed onto the outer peripheral surface of the graphite electrode 1. The annular cooling pipe 3 is arranged between an electrode holder (not shown) that holds the upper portion of the graphite electrode 1 and a furnace lid (not shown) of the arc electric furnace.

The spray nozzles 4 on the inner surface of the annular cooling pipe 3 are directed toward the center of the graphite electrode 1. As shown in FIG. 3, the tip nozzle portion 4a of each spray nozzle 4 is inclined downward by 1
It is inclined at a downward inclination angle θ of more than 0 ° and 35 ° or less. When the spray nozzle 4 is attached in this manner, the continuously supplied cooling liquid 2 is jetted obliquely downward from each spray nozzle 4 of the cooling pipe 3, and the cooling liquid 2 is denoted by reference numeral 2 in FIG.
As indicated by a, the graphite electrode 1 flows along the outer peripheral surface of the graphite electrode 1, and while the cooling liquid 2 descends downward, the graphite electrode 1 is cooled to the lower graphite electrode 1 in the furnace involved in refining. To do.

As shown by reference numeral 2a, the cooling liquid 2 flows in layers along the outer peripheral surface of the graphite electrode 1. Therefore, even when the cooling liquid 2 enters the arc electric furnace, the cooling liquid is vaporized by the internal heat and disappears. However, there is no room for an aqueous reaction, and hydrogen generated by the reaction does not enter the molten steel.

When spraying with a downward inclination as described above, it is necessary to keep the spraying amount within an appropriate range of 0.8 to 35 liters / minute, preferably 6 to 35 liters / minute. An optimum value is obtained within the range corresponding to the diameter of the graphite electrode, and the cooling liquid having this optimum value is sprayed to cool. When cooled in this way, the cooling liquid 2 scarcely scatters, and most of the cooling liquid 2 is contained in each graphite electrode 1 of the graphite electrode group.
Flowing over the outer peripheral surface of the arc, enters the arc electric furnace, and cools to the tip of the lower graphite electrode. The cooling is properly cooled without overcooling, and the electrode unit is wide. Decrease.

In this case, the downward tilt angle θ is 10 ° to 3
Within the range of 5 °, when the injection pressure is properly adjusted, the amount reflected by the graphite electrode is small, the cooling effect up to the tip is sufficient, and the electrode unit consumption is also reduced.

Further, the lower limit of the proper range of the flow rate of the cooling liquid is 0.8 liters / minute, especially 6 liters / minute. Below that, even if the downward inclination angle θ is within the above range. This is because the flow rate of the cooling liquid is insufficient and the predetermined cooling effect cannot be achieved.

Further, the flow rate of the cooling liquid is 3 which is the upper limit of the proper range.
If it exceeds 5 liters / minute, the entire graphite electrode array will be excessively cooled even with a graphite electrode having a considerably large diameter, and on the contrary, extra power will be required to heat the supercooled portion and the power consumption rate will increase, which is preferable. Because there is no.

In the above description, an example in which the cooling liquid is blown out from a plurality of nozzles has been shown, but under the above conditions, the cooling liquid can be blown out from one nozzle.
In this case, the structure of the cooling device itself can be made compact.

[0055]

【Example】

Embodiment 1 FIG. First, as shown in Table 1, using a graphite electrode array in which graphite electrodes of various diameters were connected via nipples, a cooling liquid mainly consisting of tap water was directed downward at an inclination angle θ (= 15 °) above the furnace lid. , 20 °) while inclining and spraying to cool, the scrap material was melted in an arc electric furnace for steelmaking to perform arc refining.

At this time, the flow rate of the tap water as the cooling liquid was changed for each graphite electrode for each diameter, and the electrode unit and power unit for the diameter and flow of the graphite electrode were determined.

The results are shown in Table 1.

[0058]

[Table 1]

[0059]

[Table 2]

In Table 1, the optimum water amount, the excessive water amount and the excessive water amount are as follows.

The relationship between the amount of cooling water consisting of cooling water and the electrode unit and power unit was determined for each of the eight graphite electrodes having different diameters, and the electrode unit and power unit were the best results. The amount of water that indicates is determined as the optimum amount of cooling water.

The excessive water amount is smaller than the optimum water amount, and the excess water amount is larger than the optimum water amount.

Next, within the range of the optimum amount of water thus obtained, one water amount was determined as an appropriate value for each graphite electrode, and an experiment was conducted on the electrode unit.

As is clear from Table 2, even if the water is for jetting, that is, even if the downward inclination angle θ is in the range of 10 to 35 °, the water amount is within the range of the optimum water amount corresponding to each electrode diameter. Without it, a significant reduction of the electrode unit consumption, which is important in the operation of the electric furnace, that is, the electrode unit unit of 2.5 to 1.2 kg / t cannot be achieved.

Even from the fact that it is an electrode unit that occupies a major part of the operating cost in the electric furnace operation,
This is an extremely important feature.

Further, when the same experiment was performed using one spray nozzle, the same results as those shown in Table 1 and Table 2 were obtained.

[0067]

As described in detail above, in the method of the present invention, the graphite electrode array in which the graphite electrodes are sequentially connected via the nipple is energized to melt the metal in an electric steelmaking furnace. At the time of refining, the cooling liquid is tilted downward with a downward tilt angle of more than 10 ° and 35 ° or less with respect to the horizontal level toward the outer periphery of the graphite electrode of the graphite electrode array above the furnace lid of the electric steelmaking furnace. While spraying,
The spray amount of the cooling liquid is determined within a range of 0.8 to 35 liters / minute in accordance with the diameter of the graphite electrode to be cooled, and the spray amount such as the optimum water amount is obtained. A quantity of cooling liquid is sprayed to cool the graphite electrode.

When the metal is melted and refined while spraying the cooling liquid in this manner, the oxidation consumption of the graphite electrode during the melting and refining is suppressed to a minimum, and the electrode unit consumption is greatly reduced and the operation is performed. The power consumption per unit time can be greatly reduced, and even if the furnace lid is made of inexpensive refractory such as chamotte, it does not generate hydrogen gas due to aqueous reaction in the arc electric furnace. It does not impair the service life.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of refining a metal while spraying a cooling liquid on a graphite electrode to cool the graphite electrode by the method of the present invention.

FIG. 2 is an explanatory diagram showing a part of the annular cooling pipe shown in FIG. 1 by cutting.

FIG. 3 is an explanatory view showing a part of the annular cooling pipe shown in FIG. 2 in an enlarged manner.

FIG. 4 is an explanatory diagram of a conventional cooling device.

[Explanation of symbols]

 1 Graphite electrode 2 Cooling liquid 3 Annular cooling pipe 4 Spray nozzle θ Downward tilt angle

Claims (5)

[Claims] 1. A graphite electrode array, to which graphite electrodes are sequentially connected through a nipple, is energized to a horizontal level toward the outer periphery of the graphite electrode of the graphite electrode array above the furnace lid of the electric steelmaking furnace. Inject downward with a downward inclination angle in the range of 10 ° to 35 °, spray the cooling liquid, and spray.
While cooling the graphite electrode array, when the metal in the electric steelmaking furnace was arc-melted and refined, the spray amount of the cooling liquid was set to 0.
A method for melting and refining a metal in an electric steelmaking furnace, characterized in that it is set to 8 to 35 liters / minute. 2. Electric steelmaking, characterized in that the spraying amount of the cooling liquid is within the range of more than 6 liters / minute and up to 35 liters / minute corresponding to the diameter of the graphite electrode. Method for melting and refining metals in a furnace. 3. The optimum amount of the cooling liquid is 6 to 9 when the diameter of the graphite electrode to be cooled is 400 mm ± 20 mm.
L / min, the diameter of the graphite electrode to be cooled is 450
When the diameter of the graphite electrode to be cooled is 8 to 12 liters / minute, the diameter of the graphite electrode to be cooled is 500 mm ± 30 mm, and the diameter of the graphite electrode to be cooled is 550 mm ± 20 mm. 12 to 17 liters / minute, the diameter of the graphite electrode to be cooled is 600 mm ±
14 to 20 liters / minute in the case of 30 mm, 1 in the case of the diameter of the graphite electrode to be cooled being 650 mm ± 20 mm
7 to 24 liters / minute, 20 to 28 liters / minute when the diameter of the graphite electrode to be cooled is 700 mm ± 30 mm
Min., The diameter of the graphite electrode to be cooled is 750 mm ± 30
The method for melting and refining metal in an electric steelmaking furnace according to claim 1 or 2, characterized in that it is 23 to 32 liters / minute in the case of mm. 4. The method for melting and refining metal in an electric steelmaking furnace according to claim 1, 2 or 3, wherein water is injected as the cooling liquid. 5. The metal in an electric steelmaking furnace according to claim 1, 2, 3 or 4, wherein the cooling liquid is a cooling liquid containing an antioxidant and the balance being substantially water. Melting and refining method.