JPH02267489A - Wall electrode for dc arc furnace - Google Patents

Abstract

PURPOSE:To reduce loss such as melting loss, etc., and to improve durability of a furnace wall electrode by employing a plug electrode of specific structure formed with a passage for uniformly passing cooling gas. CONSTITUTION:A furnace bottom for a DC arc has a shell in which amorphous refractory materials 2 are lined inside permanent bricks 1 and its outside is supported by an iron sheath 3, an electrode mount 4 is formed therethrough, and plug electrodes 5 are disposed in the mount 4. Plug electrodes 5 are formed by gathering a plurality of tubes 6 made of conductive metal material such as copper, etc., and filling refractory material 7 having excellent heat resistance. A distribution chamber 8 is formed under the electrodes 5, one end of the tube 6 buried with the electrodes 5 is opened, and the other end of the tube 6 is opened inside a furnace. A gas supply tube 9 connected to a gas supply source is opened in the chamber 8. Since power is supplied from a power supply cable 13 to the electrodes 5 while supplying gas 10, heat transferred from melted metal in the furnace to the tubes 6 is carried out with the gas 10 passing the tubes 6 together with Joule heat generated by the conduction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a furnace wall electrode for a DC arc furnace used for melting metal materials, refining molten metal, and the like.

[Conventional technology]

As an arc furnace for melting and refining, a current is passed between an electrode placed above the molten metal charged in the furnace and an electrode attached to the furnace bottom, side wall, etc., to melt metal materials. ,
Direct current arc furnaces are known for refining molten metal.

Furnace wall electrodes in this type of DC arc furnace are exposed to extremely harsh cloud environments due to heat received from the high-temperature molten metal in the furnace, Joule heat generated when a supplied current passes through them, and the like.

Therefore, various proposals have been made to withstand this atmosphere and improve the durability of the furnace wall single pole.

For example, in Japanese Patent Application Laid-Open No. 57-152697, a plurality of rod-shaped electrodes are embedded in a heavy-duty material at the bottom of the furnace that penetrates through the furnace bottom, and the portion of the rod-shaped electrodes that protrudes from the furnace shell is cooled with a coolant such as cooling water. are doing.

[Problem to be solved by the invention]

However, even if the rear end of the electrode that protrudes from the furnace shell is cooled and heat is transferred from the tip to the rear end by heat conduction, the electrode tip remains at a low temperature due to the resistance of the electrode itself. That is difficult. Further, the electrode itself may melt due to Joule heat generation. In this regard, when using electrodes made of metal materials such as iron as exemplified in the above-mentioned publication, the tips of the electrodes are at high temperatures and come into contact with molten metal, so melting and damage of the electrodes can still be sufficiently suppressed. Can not do it. Moreover, since it is necessary to incorporate a cooling mechanism into the rear end of the electrode, the structure inevitably becomes complicated.

Therefore, the present invention uses a plug electrode, which is made by bundling tubes made of a large number of conductive materials, as an electrode embedded in the furnace wall, so that the electrode can be cooled over its entire length by the gas sent into the tube. The purpose is to provide a furnace wall electrode with excellent durability.

[Means to solve the problem]

In order to achieve the object, the furnace wall electrode of the present invention includes a plug electrode installed in an electrode mounting part opened in the furnace wall of a DC arc furnace, and a distribution chamber provided at the bottom of the plug electrode.
and a gas supply pipe opened inside the distribution chamber,
The plug electrode is characterized in that a plurality of tubes made of a conductive material are assembled, and the gaps between the tubes are filled with a refractory material.

〔Example〕

FIG. 1 is a sectional view showing the vicinity of an electrode buried in the bottom of a DC arc furnace. However, the present invention is not limited to the hearth bottom.
Of course, the same applies to the side walls as well.

The bottom of the DC arc furnace has a furnace shell in which the inside of a permanent brick 1 is lined with a monolithic refractory 2 and the outside is supported by an iron shell 3. And these permanent bricks 1. An electrode mounting portion 4 is formed by penetrating the monolithic refractory 2 and the iron skin 3.

A plug electrode 5 is arranged inside the electrode mounting section 4 . As shown in FIG. 2, this plug electrode 5 is made by assembling a plurality of tubes 6 made of conductive metal material such as copper, and inserting a refractory material 7 with excellent heat resistance between the individual tubes 6. It is filling. Although the pipe body 6 does not limit the present invention,
For example, 10 to 20 hollow tubes with an outer diameter of 4 fins and an inner diameter of 2 g.
Use in bundles. Furthermore, as the refractory material 7 that fills the gap between the tube bodies 6, magnesia-carbon or the like is used.

As a result, a large number of holes penetrating in the direction of the furnace wall are formed inside the plug electrode 5.

A distribution chamber 8 is formed below the plug electrode 5, and one end of the tube 6 embedded in the plug electrode 5 opens. The other end of the tube body 6 opens to the inside of the furnace as shown in FIG. Furthermore, a gas supply pipe 9 connected to a gas supply 11151 (not shown) opens inside the distribution chamber 8 . The gas 10 sent through the gas supply front 9 is once expanded in the distribution chamber 8 and then introduced into each tube body 6. Therefore, there is no difference in the flow rate of the gas 10 flowing through the individual pipe bodies 6, and the gas 10 is blown into the furnace with an even flow rate distribution with respect to the cross section of the plug electrode 5.

This distribution chamber 8 is supported by a fixture 12 fixed to the furnace wall via an insulator 11. In this way, the electrode mounting part 4
While flowing the gas 10 through the plug electrode 5 placed in the
Power is supplied from the power supply cable 13. Therefore, the heat transferred from the molten metal in the furnace to the tube body 6 is transferred to the gas 10 passing through the inside of the tube body 6 along with the Joule heat generated by energization.
carried away by. This cooling method does not cool the rear end of the electrode while transmitting heat from the tip to the rear end, as in the conventional method, so the entire plug electrode 5 is cooled uniformly. Therefore, the tip of the plug electrode 5, which is exposed to particularly severe conditions, is maintained at a low temperature, and the durability of the electrode is greatly improved.

The gas 10 used to cool the plug electrode 5 is blown out from the tip of the tube 6 into the furnace and stirs molten metal such as molten steel. Therefore, melting of metallic materials.

Refining etc. are also carried out quickly.

The gas 10 blown into the furnace is thought to diffuse into the molten metal after passing through a mushroom-shaped multilayer metal structure having fine holes formed by gas cooling near the tip of the plug electrode 5. That is, direct contact between the plug electrode 5 and the molten metal or static pressure of the molten metal applied to the tip of the plug electrode 5 is reduced by blowing the gas IO,
It is presumed that this also lengthens the life of the plug electrode 5.

〔Effect of the invention〕

As explained above, in the present invention, by using a plug electrode in which a passage is formed through which cooling gas passes evenly, the tip part inside the furnace that is in contact with the high-temperature molten metal is also kept at a low temperature. maintained. Therefore, wear and tear such as melting damage is reduced, and the durability of the furnace wall electrode is improved. Further, since the gas blown into the furnace has the effect of stirring the molten metal, melting, refining, etc. are performed quickly.

[Brief explanation of drawings]

FIG. 1 shows a furnace wall electrode of the present invention applied to the bottom of a DC arc furnace, and FIG. 2 is a sectional view showing a plug electrode in which a large number of tube bodies are assembled. 1: Permanent brick 2: Monolithic refractory 3: Iron shell
4: Electrode attachment part 5 nib lug electrode 6:
Pipe body 7: Refractory 8: Distribution chamber 9: Gas supply pipe lO: Gas 11: Insulator 12: Installation tool 13: Power supply cable

Claims (1)

[Claims] 1. It is equipped with a plug electrode attached to an electrode attachment part opened in the furnace wall, a distribution chamber provided at the bottom of the plug electrode, and a gas supply pipe opened inside the distribution chamber, and the plug 1. A furnace wall electrode for a DC arc furnace, characterized in that the electrode is made by assembling a plurality of conductive material tubes whose interiors serve as gas passages, and filling the gaps between each tube with a refractory material.