JPH0542993U - Wall electrodes of DC arc furnace - Google Patents

Abstract

(57) [Summary] [Purpose] By efficiently cooling the rod electrodes,
(EN) A furnace wall electrode having excellent durability that suppresses the melting rate of refractories around a rod-shaped electrode. In a furnace wall electrode of a DC arc furnace, one end of which is composed of a rod-shaped electrode facing the inside of the furnace, the other end of the rod-shaped electrode is flush with the furnace wall without protruding outside the furnace, and the other end At the end face of the
By adopting a structure for cooling the rod-shaped electrode, the cooling effect of the rod-shaped electrode can be enhanced and the melting depth of the rod-shaped electrode can be made extremely shallow. Therefore, the melting rate of the refractory around the rod-shaped electrode is suppressed, and the life of the electrode is significantly extended. As a result, the work of repairing the refractory around the rod-shaped electrode is significantly reduced, so that the operability and productivity can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a furnace wall electrode of a DC arc furnace used for melting metal materials, refining molten metal, and the like.

[0002]

[Prior Art]

 As a refining arc furnace, an electric current is passed between the electrode placed above the molten metal charged in the furnace and the electrodes attached to the furnace wall such as the bottom and side walls to refine the molten metal. DC arc furnaces are known. The bottom electrode in this type of DC arc furnace is exposed to an extremely harsh atmosphere due to the heat received from the high-temperature molten metal in the furnace, the heat generated by the electric current passing through the furnace, and the like.

Therefore, various proposals have been made to withstand this atmosphere and improve the durability of the furnace bottom electrode. For example, in the furnace wall electrode disclosed in Japanese Patent Publication No. 63-43675, a side surface (hereinafter referred to as a protruding portion side surface) of a portion where the electrode penetrates the furnace wall and projects outside the furnace is used as a coolant passage. It is disclosed that a cooling sleeve is attached to the end face (hereinafter, referred to as a lower end face) of a cooling cap for a coolant passage, and a coolant such as water is circulated in the coolant passage to forcibly cool the electrode. There is.

[0004]

[Problems to be solved by the device]

 However, since the cooling sleeve has a cylindrical shape, a gap is required between the rod-shaped electrode and the cooling sleeve. Therefore, the cooling effect is not always sufficient.

On the other hand, although the lower end surface and the cooling cap are connected by bolts, the adhesion is good, but since they are apart from the heat source, the cooling effect is still insufficient.

Therefore, the rod-shaped electrode melts over a relatively wide range from the inside of the furnace due to heat received from the high-temperature molten metal in the furnace. Therefore, melting loss of the refractory material around the molten rod-shaped electrode is promoted, and a dramatic improvement in electrode life cannot be expected.

Therefore, an object of the present invention is to provide a furnace wall electrode having excellent durability by suppressing the melting rate of the refractory around the rod electrode by efficiently cooling the rod electrode.

[0008]

[Means for Solving the Problems]

 In order to achieve the object, the furnace wall electrode of the present invention is a furnace wall electrode of a DC arc furnace, one end of which is composed of a rod-shaped electrode facing the inside of the furnace, and the other end of the rod-shaped electrode is projected outside the furnace. Without cooling, the surface is made flush with the furnace wall, and a cooling cap is fastened to the end surface of the other end by bolts to be in close contact with the furnace wall to cool the rod-shaped electrode.

[0009]

[Action]

 In the present invention, the coolant is supplied to the cooling cap provided on the end face of the rod electrode, and the coolant carries away heat from the rod electrode when passing through the cooling cap, but the end face of the rod electrode and the cooling cap are bolted together. As a result, the heat transfer is good because it is always in close contact, and the rod-shaped electrode is flush with the furnace wall without protruding outside the furnace. Since the rod-shaped electrode is relatively close to, the melting range of the rod-shaped electrode from the inside of the furnace is reduced and the melting rate of the refractory around the rod-shaped electrode is suppressed.

The inventors obtained the relationship between the cooling range of the rod-shaped electrode and the melting depth of the rod-shaped electrode by simulation calculation. It is shown in FIG. In this simulation calculation, the actual results in the actual reactor and the calculation results are in good agreement, and it has been fully confirmed in advance that the actual reproducibility is very good.

In FIG. 2, the vertical axis represents the melting depth of the rod-shaped electrode from the inner surface of the furnace. The horizontal axis shows the cooling range of the rod-shaped electrodes.The numerical value shows the length of the rod-shaped electrodes protruding outside the furnace.If these rod-shaped electrodes protrude outside the furnace, the side surface of the protruding part It is assumed that there is cooling on both bottom surfaces (indicated by ●). In addition, these indicate a state in which there is no gap on the side surface of the projecting portion, but Δ indicates a case where there is a slight gap on the side surface of the projecting portion.

On the other hand, when the numerical value is 0, it means that the rod-shaped electrode of the present invention is flush with the furnace wall without protruding outside the furnace (indicated by ◯).

According to FIG. 2, when the rod-shaped electrode is projected outside the furnace, the side surface of the protruding portion is compared with the case where the rod-shaped electrode of the present invention is flush with the furnace wall without protruding outside the furnace. Even if both bottom surfaces are cooled, the melting depth of the rod electrode becomes extremely deep. This is because the heat flow from the heat source is no longer in a straight line and is branched to both the side surface of the protrusion and the cooling surface of the lower end surface, which deteriorates the cooling efficiency. Further, if there is a gap on the side surface of the protruding portion, the melting depth of the rod-shaped electrode becomes deeper. As described above, the melting depth of the rod-shaped electrode is extremely different depending on whether the rod-shaped electrode is projected to the outside of the furnace or not. The case clearly proves to be very advantageous.

[0014]

【Example】

 FIG. 1 shows an embodiment of a furnace wall electrode structure according to the present invention. One end of the rod-shaped electrode 1 is in contact with the molten metal 14 inside the furnace, and the other end is flush with the furnace wall 4 without protruding outside the furnace, and the cooling cap 2 is attached to the end face by a fastening bolt 6. It has been concluded. The rod electrode 1 is surrounded by a surrounding refractory material 5.

Cooling water is supplied to the cooling cap 2 through a water supply pipe 12 and discharged through a drainage pipe 13 by a cooling water supply device (not shown), for example.

The cooling cap 2 has a flange 7, and the rod-shaped electrode 1 is fixed to the furnace wall 4 by connecting the flange 7 and the furnace wall 4 with a mounting bolt 8. However, since the rod-shaped electrode 1 expands due to the heat received from the molten metal 14 and the Joule heat generated by energization, a spring 9 is installed below the flange 7 to absorb the expansion.

Power supply to the rod-shaped electrode is performed through a water supply pipe 12 from a power supply facility (not shown), but in order to electrically insulate the rod-shaped electrode 1 from the furnace wall 4, the mounting bolt 8 is not The insulating seat 10 and the insulating sleeve 11 are installed.

FIG. 2 shows the relationship between the cooling range of the rod electrode and the melting depth of the rod electrode.

[0019]

[Effect of the device]

 As described above, in the furnace wall electrode of the present invention, the other end of the rod-shaped electrode is flush with the furnace wall without protruding outside the furnace, and the cooling cap is bolted to the end face of the other end. Since the structure is such that the rod electrodes are cooled by closely adhering to each other, the cooling effect of the rod electrodes is high, and the melting depth of the rod electrodes becomes extremely shallow. Therefore, the melting rate of the refractory around the rod-shaped electrode is suppressed, and the life of the electrode is significantly extended. Furthermore, the work of repairing refractories around the rod-shaped electrode will be greatly reduced, and improvement in operability and productivity can be achieved.

[Brief description of drawings]

FIG. 1 is a view showing an example electrode of a furnace wall electrode structure according to the present invention.

FIG. 2 is a diagram showing a relationship between a cooling range of a rod-shaped electrode and a melting depth of the rod-shaped electrode.

[Explanation of symbols]

1 ... Rod-shaped electrode 2 ... Cooling cap 4 ... Furnace wall 5 ... Surrounding refractory 6 ... Fastening bolt 7 ... Flange 8 ... Mounting bolt 9 ... Spring 10 ... Insulator 11 ... Insulation sleeve 12 ... Water supply pipe 13 ... Drainage pipe 14 ... Melt metal

Claims (1)

[Scope of utility model registration request] 1. A furnace wall electrode of a DC arc furnace, one end of which comprises a rod-shaped electrode facing the inside of the furnace, the other end of the rod-shaped electrode being flush with the furnace wall without protruding outside the furnace, Attach the end face of the end to the cooling cap with fastening means,
A furnace wall electrode of a DC arc furnace, characterized in that the rod-shaped electrode is cooled.