JPH012294A - Metal melting and refining method and electrode cooling device used therefor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Field of Application The present invention relates to an electrode cooling device for use in metal melting and refining processes, and more particularly, it relates to an electrode cooling device for use in metal melting and refining processes. When melting and refining metal by passing current through the graphite electrode connected to the electrode, a cooling liquid such as cooling water is continuously sprayed onto the outer peripheral surface of the upper graphite electrode held by the electrode holder to cool it. In particular, spraying the coolant at a downward slope of 10 to 35 degrees with respect to the horizontal level,
The graphite electrode is effectively cooled by minimizing the scattering of the coolant during spraying, suppressing oxidation wear on the outer circumferential surface of the graphite electrode, and greatly reducing the electrode base level. By increasing the durability of the electric arc furnace furnace box, it is possible to melt metals by high voltage and high power factor operation, and to improve 'R11! method and the electrode cooling device used therefor.

Made using conventional technology! In electric arc melting and refining of I14 and metals, as the cost of electrical energy decreases, I'i! l
There is a need for a method that suppresses wear and tear and thereby lowers the electrode unit consumption. As a means of suppressing this oxidation consumption, it has been proposed and implemented to cool graphite electrodes.As one of the cooling methods, in graphite electrodes that are connected in sequence, the upper electrode has a structure in which the inside is cooled with cooling water. ,
Configured as a water-cooled non-consumable electrode, a graphite electrode is connected to the lower end of this non-consumable electrode via a nipple, and during refining operations such as melting, part of the non-consumable electrode is cooled to cool the lower end graphite electrode. However, only the graphite electrode is consumed and t*m
Methods and devices have been proposed. For example, U.S. Pat. No. 4.41+3,014, U.S. Pat. A structure is described in which cooling water is introduced into the non-consumable electrode, and the cooling water cools the wall surface of the non-consumable electrode and the graphite electrode connected to the lower end.

In addition, Japanese Patent Application Publication No. Sho GO-501879 and Japanese Patent Application Publication No. Sho GO-501880 have a water-cooled non-consumable electrode composed of a tubular body made of graphite, and a central hole of the non-consumable electrode. A structure is described in which cooling water is introduced into the inside of the electrode, and the wall surface of the non-consumable electrode and the graphite electrode connected thereto are cooled by the cooling water.

In this way, when the graphite electrode connected to the part is cooled by cooling the non-consumable electrode at the upper end, oxidative consumption of the tip and outer circumference of the graphite electrode is suppressed, and a reduction in electrode consumption can be achieved.

However, the graphite electrode connected to the bottom is consumed,
When this graphite electrode is removed, it is moved off-line from the electric furnace and the used graphite electrode is removed from the nipple, and if necessary, the nipple is also removed from the non-consumable 'Fli electrode. Also,
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 cooling the graphite electrode connected to the bottom using a water-cooled non-consumable electrode as described above, it is necessary to transport the graphite electrode off-line for replacement and perform the removal and connection work there. hand,
The work becomes extremely complicated. In addition, if the graphite 2 is repeatedly removed and connected, the threads of the graphite electrode, non-consumable electrode, nipple, etc. may be deformed, torn, or damaged.
Poor connections and increased electrical resistance may occur, causing operational problems.

From this point on, as mentioned above, in order to cool the graphite electrode connected to the lower part, without using a water-cooled non-consumable electrode, the A cold FA device is described in which the surface of a graphite electrode protruding upward is cooled by spraying cold water thereon, and this cooling device is constructed as shown in FIG. That is, in FIG. 1, reference numeral 1 indicates a furnace lid of an arc electric furnace, a graphite electrode 2 is inserted into this furnace lid 1 so as to be able to rise and fall freely, a graphite electrode is connected to the lower part of this graphite electrode 2, Graphite is placed in an electric arc furnace and is used for refining purposes such as steel manufacturing. Above the furnace M1, the upper end of the graphite electrode 2 is held by an electrode holder 3. An annular cooling pipe 4 surrounding the outer periphery of the graphite electrode 2 is provided on the lower surface of the electrode holder 3, and a plurality of vertical pipes 5 extend downward from the annular cooling pipe 4.
A nozzle 6 is provided on the inner surface of each vertical pipe 5 and is directed toward the surface of the graphite electrode. Therefore, the cooling water supplied to the annular cooling pipe 4 descends along each vertical pipe 5, and the cooling water is sprayed onto the outer circumferential surface of the graphite electrode from each nozzle 6 on the inner surface, thereby cooling the graphite electrode.

However, in the cooling device shown in FIG. 1, the cooling water is injected from each nozzle 6 at a horizontal level or in a direction parallel to it. Therefore, when the cooling water collides with the outer circumferential surface of the graphite electrode 2, the equivalent material is reflected and scattered.
Since there is a large amount of this scattered cooling water, the electrode holder 3 and the furnace lid 1 are seriously contaminated and damaged, making it impossible to put them into practical use. Furthermore, since only a small amount of the injected cooling water contributes to cooling, the amount of cooling water used is constantly increasing, which is extremely uneconomical. Further, a large number of vertical pipes 5 protrude downward from the cooling pipe 4, and the length of this protrusion is extremely long. Therefore, when the cooling device is removed for electrode replacement, this long vertical pipe 5 becomes an obstacle, making handling extremely troublesome.

In addition to the above-mentioned drawbacks, the cooling device shown in FIG. A considerable portion of the current flowing through the electrode 2 is cut off, causing a major hindrance to operation. In other words, in the operation of an electric arc furnace, three-phase AC i! Three graphite electrodes are used corresponding to the glands, and when cooling the graphite electrodes, each graphite electrode is provided with a cooling device as shown in FIG. For this reason, since each cooling pipe 4 is annular, electromagnetic influence is exerted between the two phase graphite electrodes, while each cooling pipe 4 shields the electromagnetic force, so that the current of the graphite type [i2 is cut off,
The metal cannot be sufficiently heated by electricity, and the electric power level increases significantly, which is undesirable.

Problems to be Solved by the Invention The present invention aims to solve these problems, and specifically, sprays the cooling liquid at an angle of 10 to 35 degrees Fahrenheit with respect to the horizontal level. The present invention is characterized by providing a method for melting and refining metal, and an electrode cooling device used therefor.

<Structure of the Invention> Means for Solving the Problems and Their Effects The present invention provides 1) cooling by spraying a cooling liquid onto the outer peripheral surfaces of the upper ends of graphite electrodes connected sequentially through nipples; When melting and refining metals, the cooling liquid is heated to a horizontal level of 10
A metal melting and refining method characterized by a ~35″ upwardly slanted spraying spout.

2) An annular cooling pipe that surrounds the outer periphery of the graphite electrode and in which a cooling liquid flows is arranged between the furnace cover of the arc electric furnace and an electrode holder that holds the upper end of the graphite electrode, and the annular cooling pipe In the electrode cooling device used during melting and refining of metal, in which the cold liquid is sprayed from the inner circumferential surface opposite to the outer circumferential surface of the graphite electrode, at least one part of the Moeki annular cooling pipe is cut out to form a notch. and at least one injection hole on the inner circumferential surface of the annular cooling pipe that is inclined at 10 to 35 degrees in the direction E with respect to the horizontal level and that injects the cooling liquid in the direction of the central axis of the graphite electrode. It is characterized by the following.

Hereinafter, the configuration and operation of the means of the present invention will be explained with reference to the drawings.

FIG. 1 is a cross-sectional view of a cooling device according to the present invention, and FIG.
The figure is a perspective view of a cooling device according to a conventional example.

First, the present invention is based on, for example, the Japanese Act Publication No. 59-2335
As shown in No. 7, this method melts and refines metal by directly spraying a cooling liquid onto the outer peripheral surface of the upper end of graphite electrodes that are successively connected through nipples. The coolant does not spray at a horizontal level, but at an angle of 10 to 35 inches downward or upward with respect to the horizontal level. Therefore, the coolant hits the outer peripheral surface of the graphite electrode and also partially sprays the graphite electrode. falls along the outer circumferential surface without scattering much, and the outer circumferential surface of the graphite electrode is cooled by this cooling liquid film, and the cooling is not limited locally on the outer circumferential surface.

The length of the part that is cooled and maintained in a black state becomes longer, and the oxidation consumption of the connected graphite electrode can be greatly reduced.

Further, it is characterized in that the cooling liquid is water or that an oxidizing agent is contained in the cooling liquid. Therefore, when the coolant descends along the outer surface of the graphite electrode, the oxidation resistant agent contained therein adheres, and the oxidation resistant film formed by this adhesion effectively prevents the oxidative wear and tear of the black 1-alt electrode. Defense 1F
can.

In addition, the coolant is injected at a pressure of 0.5 to 3 klJ,' C
It is characterized by spraying at I', injection length of 0.8 to G, O1,' minutes.

Therefore, when spraying within this range, the coolant hardly scatters during spraying, and even if the coolant falls along the outer circumferential surface of the graphite electrode and enters the furnace, the coolant will instantly evaporate and vaporize. As a result, no operational problems occur within the electric furnace.

Further, as described above, when carrying out the present invention, an annular cooling pipe is disposed between the furnace lid of the arc electric furnace and an electrode holder that grips the upper end of the graphite electrode, and an annular cooling pipe is disposed inside the annular cooling pipe. A spray nozzle is provided on the circumferential surface, and a cold W liquid is sprayed from these nozzles onto the outer circumferential surface of the graphite electrode, and at least one place of this annular cooling pipe is cut out to form a notch. Therefore, even if it is electromagnetically influenced by the current flowing through the graphite electrode, no current will flow through the cooling tube due to the presence of the notch, and there is no way that the current flowing through the graphite electrode will be cut off. .

In addition, at least one spray nozzle provided on the inner circumferential surface of the annular cooling pipe is arranged downwardly with respect to the horizontal level.
arranged so as to be inclined by 35° and directed toward the central axis of the graphite electrode, or inclined by 10 to 35′ in the F direction with respect to the horizontal level and directed toward the central axis of the graphite electrode; Injection holes for injecting cooling fluid are provided in the annular cooling pipe. Therefore, when the cold FA liquid from the nozzle collides with the outer circumferential surface of the graphite electrode, it flows down along the outer circumferential surface without scattering to the surroundings, forming a cooling liquid battle. Therefore, the outer circumferential surface of the graphite electrode held by the electrode holder can be uniformly cooled over its entire length, and the graphite consumption rate can be greatly reduced.

BEST MODE FOR CARRYING OUT THE INVENTION First, in FIGS. 2, 3, and 4, reference numeral 10 indicates a graphite electrode, and the upper end of this graphite electrode 1o is connected to the graphite electrode 2 shown in FIG. is held by the electrode holder in the same way as
A graphite electrode is connected to the lower end via a nipple, and the connected graphite electrode is inserted into the electric furnace through the furnace lid. However, in FIGS. 2, 3, and 4, especially in FIGS. 3 and 4, the electrode holder, the furnace lid, the nipple, the graphite electrode at the bottom to be connected, etc. are not shown.

In addition, when placing the graphite mold...10 in an electric furnace, draw a circle with a predetermined radius around the center of the electric furnace,
Three graphite electrodes are placed at intervals so as to be positioned above this circle. The reason why three graphite electrodes are arranged here is that three-phase alternating current is used as a power source. However, in FIG. 2, FIG. 3, and FIG. 4, one graphite electrode 10 is shown as a representative example, but among three graphite electrodes, each graphite electrode 10 has the above-mentioned structure. Graphite electrodes are connected to the lower part through nipples, and electricity is applied to each of these electrodes in an electric furnace to melt and refine metals such as steel.

Therefore, the outer circumferential surface 10a of at least one graphite electrode 10 among these three graphite electrodes, the outer circumferential surface 10a of the graphite electrode 10 between the electrode holder and the furnace cover, is substantially free from water, for example, inside the body. The cooling liquid 11 consisting of Cool.

That is, when cooling the outer circumferential surface 10a of the graphite electrode 10 by spraying the coolant 11, it can be sprayed and cooled by any method, but the graphite electrode 10 can be cooled by spraying the coolant 11 substantially parallel to the horizontal level L-L. When spraying onto the outer circumferential surface 10a of the electrode 10, the collision energy of the spray becomes high, and a considerable portion of the coolant 11 is scattered to the outside, and even on the outer circumferential surface 10a of the graphite electrode 10, only the collided portion is locally cooled. Can not. Furthermore, the scattered ReiW water accelerates wear and tear on the electrode holder and furnace cover.

From this point of view, in the present invention, the cooling pipe 12 is arranged outside the graphite type wA10, and the cooling liquid 11 is introduced from the introduction duct of this cooling pipe 12].
Spray at a downward angle of 35°. This cooling pipe 12
Preferably, the cooling pipe 12 is disposed directly below the electrode holder between the electrode holder that grips the upper end of the graphite electrode 10 and the upper M (not shown) of the electric arc furnace.

The cold FII tube 12 is formed in an annular shape concentrically with the graphite electrode 10 so as to be spaced a predetermined distance from the outer circumferential surface 10a of the graphite electrode 10. At least one notch or hole 13 is provided. That is, as described above, for example, when three graphite electrodes 10 are arranged concentrically around the center of an electric arc furnace and a graphite electrode is connected to each for operation, each graphite electrode 10 and its The cooling pipes 12 surrounding each graphite mold 411i+0 are electromagnetically influenced individually or mutually by the current flowing through the connected graphite electrodes. This cold FiI tube 12
Due to the electromagnetic influence, part of the current flowing through the graphite electrode 10 and the graphite electrode connected thereto is cut off, impairing the operation of the electric furnace. Therefore, in consideration of this electromagnetic influence, a notch 13 is provided in a part of the cold FA pipe 12 so that the cooling pipe 12 is configured to be free from electromagnetic influence. In layman's terms, as mentioned above, in an arc electric furnace, three phase alternating current is used as a power source, so three graphite electrodes 10 are arranged concentrically corresponding to each exchange meeting. Therefore, each of these graphite electrodes 10 influences each other electrically, and each of the surrounding cooling pipes 12 receives this influence, and if the cooling pipes 12 are continuous in a winding shape, A current flows, and the electromagnetic influence based on this current affects the current flowing through the graphite electrode 10, which hinders operation.
However, if a notch 13 is provided in a part of the cooling pipe 12, a current will be induced in the cooling pipe 12 even if it is electromagnetically influenced by the graphite electrodes 10 surrounding the 10 internal graphite electrodes. There is no flow and there is no problem in operation.

The cooling pipe 12 is made of a material that is not affected by electromagnetism, has excellent acid resistance, and has excellent moldability. Preferably, it is made of steel or the like.

Even if it is made of a material other than metal, it may be made of a material that is not affected by electromagnetism and has oxidation resistance, such as ceramic.

Further, in order to inject and spray the cooling liquid 11 from the inner peripheral surface of the cooling pipe 12, a plurality of spray nozzles 14, for example, 4 to 8 spray nozzles, are arranged at intervals on the inner peripheral surface of the cooling pipe 12. establish.

For each spray, the nozzle 14 is directed radially toward the center of the graphite electrode 10, and for each spray, the nozzle 14 is directed toward the center of the graphite electrode 10.
4a is inclined diagonally downward at an inclination angle θ=10 to 35°, as shown in FIGS. 4 and 5. If the coolant is sprayed at an angle within this range, the introduction duct l-12
The cooling liquid 11 continuously supplied from the cooling pipe 12 is sprayed diagonally downward from the nozzle 14 as shown in FIG. That is, when the cold l, l liquid 11 is sprayed at a downward angle, when it collides with the outer circumferential surface 10a of the graphite electrode 10, the impact 1 energy is relaxed, and the coolant 11 is hardly scattered. Since it is directed downward, a thin coolant film 118 is formed along the outer circumferential surface 10a of the graphite mold 10. Therefore, while this film 11af descends downward along the outer peripheral surface 10a of the graphite electrode 10, the cooling liquid 11 flows into the graphite electrode 10.
The graphite electrode 10 is vaporized by the internal heat, and the heat retained in the graphite electrode 10 is absorbed by the heat of vaporization, and the graphite electrode 10 is cooled well over its entire length. When the upper graphite electrode 10 is cooled in this manner, the graphite electrode connected to its lower end is cooled by the upper graphite electrode, and oxidative consumption of the lower graphite electrode is suppressed. In other words, since graphite electrodes become conductive, if the upper graphite electrode that is gripped by the electrode holder is cooled, and especially if it is cooled as widely as possible to the lower end, the graphite electrode connected to the lower part will also be well-conducted. It is cooled and the electrode consumption rate is greatly reduced.

Moreover, when cooling in this way, the cooling liquid 11 is formed as a film Ha on the outer circumferential surface 10B of the @lead electrode 10 held by the electrode holder, and a part of it enters into the FM of the electric furnace. At this time, the temperature inside the electric furnace is very high, and if the cooling water that has entered the furnace is not large enough, it will evaporate and will not be of much help to the operation, but if the top cover is made of refractory material such as magnesia This is not preferable because it impregnates it with lubrication and deteriorates its brittleness. For this purpose, the injection pressure of the coolant 11 should be 0.5 to 3 kg/#, the injection amount should be 0.8 to G,
It is preferable to adjust the temperature to a range of 0471 minutes.

Generally, when cooling water reaches the molten metal in an electric furnace, the water contained therein comes into contact with the high-temperature molten metal, causing a hydrogen explosion, which is extremely dangerous. From this point of view, the upper electrode held in the electrode holder can be used as a non-consumable electrode into which cooling water can be introduced, as described above, without spraying a cooling liquid such as cooling water onto the outer peripheral surface 10a of the graphite electrode 10. Specifically, a cooling passage is formed along its central axis, and the mouth is cooled by the cooling passage.

On the other hand, when the coolant 11 is sprayed onto the outer circumferential surface 10a of the graphite electrode 10 as in the present invention, the outer circumferential surface 10a of the graphite electrode 10 is cooled by the coolant 11, and is cooled over as wide a range as possible. It is necessary to keep the spraying of the cooling water 11 to a minimum so that even if the cooling water 11 enters the upper lid, it quickly evaporates in the furnace and does not cause the above-mentioned trouble.

To explain in more detail, without using non-consumable electrodes,
When the graphite electrodes are connected sequentially from the top and only the upper wA lead electrode is cooled, the connection of the electrodes is no different from normal operation. Therefore, it is ideal for on-site operation. Furthermore, it is an extremely excellent cooling method because it takes advantage of the fact that the graphite in the upper and lower graphite electrodes is a material with extremely good thermal conductivity. However, since the lower black VI electrode is cooled by the upper graphite electrode, the cooling effect of the lower graphite electrode is influenced by the cooling effect of the upper graphite electrode.

In other words, the rate of reduction in graphite NFiA basic unit is determined by how much the upper graphite electrode is cooled in the longitudinal direction. By the way, it has been said before,
Even if a part of the upper graphite electrode, for example only the upper end, remains black without becoming red hot, the outer periphery and tip of the lower graphite electrode connected below it may be exposed to acid. It is said that deterioration and wear and tear can be considerably suppressed. For example, when about 10% of the length of the upper graphite electrode remains black and the rest remains red-hot, the electrode consumption rate of the lower graphite electrode is reduced to over 12% by suppressing oxidation consumption. It is said that it will be done.

In this regard, when cooling the upper graphite electrode by spraying the coolant directly onto the outer circumferential surface of the graphite electrode, if the coolant is sprayed at a downward angle as in the example above, it will spread over a wide area along the length of the graphite electrode. It can be cooled to

That is, 10% of the upper graphite electrode where the coolant is directly sprayed.
Because the above parts can be maintained in a black state without becoming red hot,
Electrode consumption can be significantly reduced.

Moreover, as mentioned above, graphite'i! When spraying liquid on the outer peripheral surface of one pole to form a cold liquid film on the external surface, as shown in FIG. θ=10~35''),
The coolant 11 is applied to the outer peripheral surface 10a of the graphite electrode 10, avoiding the loop.
contact with. By spraying the coolant 11 in this manner, the coolant 11 can be sprayed onto the outer circumferential surface 10a of the graphite electrode without waste, and the upper cover 15 of the electric arc furnace is made of a magnesia-based refractory that becomes brittle when impregnated with moisture. Even though
The coolant 11 does not leak onto the top lid 15.
There is no problem with operation. Furthermore, even if the upper cover 15 is made of an alumina-based refractory material that is resistant to moisture, if the coolant 11 is sprayed in one direction, the coolant 11 will be sprayed in one direction. Compared to the case of downward spraying, the life span of the upper lid 15 is increased by about 1.5 to 2.0 times, and even more.

Further, as shown in FIG. 7, the cooling pipe 1G through which the cooling liquid 11 is sprayed in an upwardly inclined manner may be provided with a spray nozzle, but usually there is at least one injection hole 16.
A can be provided so as to be inclined in the -E direction at an inclination angle θ of 10 to 35 degrees.

A notch (not shown in FIG. 7) is formed in a part of the cooling pipe 1G, similar to those shown in FIGS. 2 and 6. Furthermore, during cooling, the cooling pipe 16 can be placed directly under the electrode holder that holds the graphite electrode 10, but it can also be placed on the surface of the upper lid 15.

In addition, as described below, when cooling the part using the cooling pipe 12 or the cold IA pipe 16, the distance between the outer peripheral surface 10a of the graphite electrode 10 and the tip nozzle 14a of the spray nozzle 14 and the injection hole 16a is It is preferable that the distance between the nozzle 14 and the injection hole IGa is about 5 to 20c+a, and the cold part liquid 11 is at a horizontal level L-
Inclination angle θ with respect to L (see Figures 5 and 7) 10
It is preferable that the cooling liquid 11 is sprayed at a pressure of 0.5 to 3 klJ t'CI' and sprayed at a time of 8 to 35°.

Under these favorable conditions, the dimensions of the electric arc furnace,
Even if the dimension and capacity change to some extent, in the case of arc electric furnaces currently in practical use, the cooling 'a11 can cool the outer circumferential surface 10a of the graphite electrode 10 well without any waste, and there is no need to cool the outer peripheral surface 10a of the graphite electrode 10. There is no scattering, and the service life can be greatly improved.

That is, when spraying the coolant with the nozzle 14 tilted downward, the inclination angle θ (see FIG. 5) of the nozzle 14 is set to 10 to
The reason for setting the angle to 35° is in addition to the above-mentioned reasons.If the spray is set to the angle O' and the spray is made from the nozzle 14 horizontally and the coolant 11 is sprayed onto the flat surface 1j, then the coolant 11
As long as the number of stones is greatly increased to 4C, the graphite electrode 10 can only be locally cooled, and at most only about 5% of its length can be kept black. Further, when spraying, a considerable portion of the cold lJI liquid 11 sometimes scatters toward the electrode holder, which tends to damage the electrode holder itself. From this point of view as well, it is preferable to set the lower limit to 10°. Furthermore, if the inclination angle θ is greater than 35', the cooling liquid 11 will spread and a portion of it will cover the top cover of the electric furnace, which will accelerate the wear and tear of the top cover itself, which is undesirable.

Also, when spraying the coolant with an upward tilt,
The inclination angle θ of the injection hole 16a (see Fig. 7) is 10 to 35°.
If it is outside the range of , a downward loop tf-
It is not formed well, and when the coolant 11 is sprayed, a large amount of the coolant is scattered outside.

Further, the cooling liquid 11 can be made of commonly available tap water or the like as it is, but it is also possible to mix an oxidizing agent such as calcium phosphate into the cooling liquid 11 and spray it.

If an oxidizing agent is mixed in in this way, the oxidizing agent in the coolant will condense and adhere to the outer peripheral surface of the E section graphite electrode 10 during spraying, forming an oxidizing resistant film, which will cause oxidative wear and tear from the outer peripheral surface. can be prevented even more effectively.

When the upper graphite electrode having the oxidizing agent adhered to the outer circumferential surface is used as the lower graphite electrode, oxidative consumption from the outer circumferential surface is more effectively suppressed, and the electrode consumption rate is further improved. In order to achieve such an effect, it is preferable to add an oxidizing agent in an amount of about 1 to T5 wt%.

In addition, when spraying the coolant while tilting it upward, the tip nozzle 14a of the nozzle 14 is sprayed as shown in FIG.
It is preferable to configure the cooling liquid 11 so that the outer circumferential surface 10a of the graphite electrode 10 is hit on the average.

In this preferred example, the tip nozzle 14a is a cold 1. I]′
1a11f It is configured to be sprayed so that it does not widen at the tip and forms a fan shape, and furthermore, a filter 141) is installed in a part of the nozzle 14 to remove foreign substances such as dust in the cooling liquid 11. It is preferable to do so (see Figure 5). Furthermore, as shown in FIG. 7, when spraying the cold fill liquid 11 with an inclination in the -L direction, similarly to -h,
It is preferable that each injection hole IGa is configured or arranged so that the coolant 11 evenly hits the outer circumferential surface 10a of the graphite electrode.

In addition, in the example shown in FIG.
S13 can be provided at any part.

For example, in the example shown in FIG. 6, a notch 13 is provided near the introduction duct h12a, and the presence of this cooling pipe 12C makes machining extremely easy. Furthermore, i<i shown in FIG.
Even in the case of the FA pipe 1G, the cutout portion can be provided at the same location.

Example 1゜ First, various types of Suzudenshu as shown in Table 1 are connected via nipples, and the upper graphite core is held with an electrode holder, and the electrodes shown in Figs. 2 and 3 are connected. As shown, cooling pipe 1
In the spraying step 2, the cold "all" was sprayed downward from the nozzle 14, and the scrap material was melted in an arc °1.6 furnace to perform arc refining. Tap water was used as the cold instant liquid, cooling water was continuously supplied at the mouth, and each spray was made from the nozzle 14 toward the outer circumferential surface 10a of the graphite electrode 10.

In addition, for comparison, arc refining was performed under the same conditions without injecting cooling water as a conventional example, and the electrode consumption rate between this conventional example and the case of the present invention was determined, and the improvement effect was investigated. , as shown in Table 1.

Table 1 At this time, the cooling pipe 11 is placed directly below the electrode holder, and the distance between the graphite electrode outer peripheral surface 10a and the spray nozzle 14 is 1.
About 5~20cm, the downward inclination angle θ of the nozzle 14 is in the range of 10□-35'', and the pressure of the cooling water is 1~3kl.
lI'C1l' range, Suiseki is 1 to 21? The number of nozzles was varied from 4 to 8.

As a result, as shown in Table 1, the improvement effect was at least 11
% or more, and there was no danger of a hydrogen explosion caused by the cooling water.

Furthermore, in the case of Test No. 4, a high angle load operation was performed using a P electrode, and the improvement effect was extremely large at 19%. Further, when cooling water is sprayed according to the present invention, it is possible to switch to operation using a normal graphite electrode. The improvement effect was extremely large at 19%.

Furthermore, when calcium phosphate 10wt', 6 was uniformly mixed in the cooling water and sprayed in each of the above cases,
The calcium phosphate remained on the electrode as a thin white film, greatly improving its oxidation resistance. As a result,
The improvement effect is at least 1-2% in each case in Table 1.
It was found that Hodomaro improved by one level and the electrode consumption rate could be reduced by one kilogram.

Also, for comparison, in the case of each test number, the pressure was 1 to 3 k with the inclination angle θ = 0° (same direction as the horizontal level).
Q.'CI? When cooling water was sprayed for 11 to 211 minutes of water w, the improvement effect was 5 to 8% compared to the conventional example.
It was about. Furthermore, during the operation, a considerable portion of the cooling water splashed onto the electrode holder, making it extremely difficult to continue operation.

Example 2 Cooling water 11 was looped downward and sprayed onto the outer circumferential surface 10a of the graphite electrode under the same conditions as in Example 1, except that the cooling water 11 was sprayed at an upward angle. However, the improvement effect was determined in comparison with the conventional example shown in Example 1, and the results are as shown in Table 2.

In the case of the mouth, Test Nos. 9 and 8 used upper lids made of magnesia-based refractories, while Test No. 7 used upper lids made of alumina-based refractories.

In addition, in this operation, the unit charge is carried out in about 2 hours as usual, and in this operation, as in Example 1,
When cooling water was sprayed downward, the RF life was only about 150 cycles even with alumina refractories.
In the case of test number 7, the person ID increased from 150 charges to 600 charges and about 450 charges.

<Advantageous Effects of the Invention> As explained in detail above, the present invention cools the outer peripheral surface of the upper end of graphite electrodes connected sequentially through nipples by directly spraying the cooling liquid to melt the metal. , in the refining method, the cooling liquid is heated at an angle of 10 to 35° to the horizontal level.
Spray at an upward or downward angle. Therefore, the cooling liquid hits the outer circumferential surface of the graphite electrode, and a part of it descends along the outer circumferential surface without scattering, and the outer circumferential surface of the graphite electrode is cooled over almost the entire length by this cooling liquid film. Among other things, when tilting upward, the coolant loops and contacts the graphite electrode, and the coolant can form a coolant film without any spouting to the outside. Therefore, the electrode holder and the top cover do not have to be damaged or worn out, and the lifespan is improved even if the electrode holder is made of magnesia-based refractories.

In addition, by directly spraying the cold liquid to cool the material and refining it, the amount of graphite electrodes can be greatly reduced not only in steelmaking but also in metal refining in general.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the cold I and Il equipment according to Kunming, and Figure 2
The figure is a perspective view of a conventional cold rA device. Code 1... Furnace lid 2... Graphite electrode 3... Electrode holder 4... Annular cooling pipe 5... Vertical vibrator 6... ... Nozzle 7 ... Graphite electrode 10a ... Outer peripheral surface of graphite electrode 11 ... Cold liquid 15 ... Furnace lid 16 ... ... Cooling pipe IGa ... Injection hole patent applicant Nippon Carbon Co., Ltd. Agent Patent attorney Yoshikatsu Matsu Attorney Fumihiro Soejima Figure 1 Figure 2

Claims (1)

[Claims] 1) When melting and refining metal by spraying a cooling liquid onto the outer circumferential surface of the upper end of graphite electrodes that are successively connected through nipples, the cooling liquid is cooled. 10 for horizontal level
A metal melting and refining method characterized by spraying at an upward angle of ~35°. 2) An annular cooling pipe that surrounds the outer periphery of the graphite electrode and in which a cooling liquid flows is arranged between the furnace cover of the arc electric furnace and an electrode holder that holds the upper end of the graphite electrode, and the annular cooling pipe In the electrode cooling device used during melting and refining of metal, in which the cooling liquid is sprayed from the inner peripheral surface opposite to the outer peripheral surface of the graphite electrode, at least one part of the annular cooling pipe is cut out to form a notch, At least one injection hole is provided on the inner circumferential surface of the annular cooling pipe, and the injection hole is inclined upward by 10 to 35 degrees with respect to the horizontal level and injects the cooling liquid in a direction toward the center axis of the graphite electrode. An electrode cooling device used during melting and refining of metals.