JP3049201B2 - DC electric furnace anode block repair method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a DC arc furnace anode block used for refining molten metal.

[0002]

2. Description of the Related Art Conventionally, a DC arc furnace for refining molten metal has a furnace bottom electrode serving as an anode and a single electrode serving as a cathode above the furnace. Then, electric energy discharged between the cathode and the anode is applied to the scrap as heat energy to dissolve the scrap. FIG. 4 is a cross-sectional view for explaining an anode block of such a DC arc furnace. As shown in the figure, an anode pin 1 made of a steel material protected by a coating material 11 and a fixed refractory 12 passes through a substrate 2 and a pin mounting plate. 3 between the anode pin 1 and the fixed refractory 12 is filled with fine-grained irregular refractory (MgO) 7. In addition, the fixed refractory 12
When an amorphous refractory is used instead of this, filling with a fine-grained amorphous refractory (MgO) 7 is not required. An anode pin is mounted on the anode pin mounting plate 3, and a cooling air wind box 4 is provided.
The cooling effect of the cooling air blown through is increased. Reference numeral 5 denotes a power cable support bracket, and reference numeral 6 denotes a power cable. Further, a steel frame 8 is provided around the anode block, and is integrated with the substrate 2 and the anode pin mounting plate 3 so that the electrode can be easily mounted and removed in a cassette type at the time of electrode replacement. A certain refractory brick 9 forms a boundary with the furnace bottom refractory material 10.

As the furnace bottom electrode refractory, magnesia / carbon type fixed refractory, magnesia / dolomite type irregular shaped stamp material and the like are used.

In such an anode block structure, when the number of uses (refining) is about 1000 ch (charge), the furnace bottom is eroded and worn as shown by a broken line A in FIG. When the remaining size becomes equal to or smaller than a predetermined size, the entire anode block is replaced.

[0005]

As described above, the life of the conventional anode block is determined by the amount of damage to each material of the furnace material to be used. If it is used to the last minute to reduce the cost, there is a possibility that an accident such as the rise of the refractory of the furnace bottom may occur. On the other hand, if the replacement is performed early with an emphasis on safety, the use cost increases. An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a DC electric furnace anode block repair method capable of achieving planned repair of the anode block and extending the service life thereof, and at the same time reducing the use cost. .

[0006]

According to the present invention, when the damage of the anode block has reached a predetermined size, the slag of the furnace bottom is removed to expose the damaged anode pin head, and the anode block is positioned with a grid-like iron frame. After adding the anode pins and adding iron powder or the like to the joints, refill with irregular shaped refractories and restart the operation. The seam is completely joined by the re-energization.

[0007]

Embodiments of the present invention will be described below. FIG. 1 is a view showing an example of an embodiment of the present invention. FIG. 1A is a plan view (a view showing a half), and FIG.
Is a side sectional view. The present invention can be applied to any of the furnace bottom refractories originally used for the anode block, such as magnesia, dolomite type stamp material, and magnesia / carbon type refractory material. Reference numeral 20 denotes a lattice-shaped iron frame. A pipe 21 having a predetermined inner diameter larger than the outer diameter of the pin is welded to the iron frame so as to correspond to each anode pin 1. The iron frame 20 may be a plate-shaped member with holes, or a bar-shaped member formed in a lattice. Positioning is performed using the grid-like iron frame 20, the damaged anode pin 1 is added, and the stamp material is filled and repaired. An anode block having a predetermined height is, for example, as shown in FIG.
At the point of damage of about 100 to 300 m / m indicated by the line A in (b), the slag on the surface of the anode block is removed, the head of the damaged anode pin 1 is exposed, and the grid-like iron frame 20 to which the pipe 21 is attached is attached. Is set on the anode block. In this case, about four places of the anode block are selected, and the grid-like iron frame 20 is set horizontally using a pin or the like.

Next, the contact pin 22 is inserted through the pipe 21 and brought into contact with the head of the anode pin 1, and as shown in FIG. Powder (iron powder, iron scraps) is put into a specified thickness. Next, the refractory 25 is filled with the iron frame 2.
Remove 0 and refill.

In this case, the seam portion of the pin is only partially welded, but the enamel in the normal operation melts the Dalai powder and is completely joined.

[0010] Since the damage to the pins is not uniform, long contact pins are prepared and cut at the site. If a self-flowing stamp material is used, the work of tamping can be omitted.

FIG. 3 is a view showing another example of the present invention. A pipe 30 is fitted or abutted on the head of the anode pin 1 and iron powder and / or iron balls (steel balls) 31 are placed in the pipe. It is packed with a stamp material. If the upper part of the pipe 31 is left open, the molten metal flows in the normal operation, and the iron powder or iron ball melts and becomes a pin when energized.

[0012]

[Example] An anode block using a dolomite stamp material as a refractory was 900 m at the start.
Repair was performed when the / m height was damaged by about 300 m / m. The grid iron frame has a pitch of 139 m / m.
As shown in (a), a 50 m / m long pipe was welded,
A contact pin having the same diameter as the 2φ anode pin was used. A contact pin having a sharpened tip was inserted through a pipe, the stalk was removed, the contact pin was brought into contact with the exposed anode pin head, and a welding rod was positioned at this contact portion to perform spot welding. Next, iron powder is put into this seam portion in a layered manner at a thickness of about 5 m / m, a stamp material is put into the seam at a thickness of 200 m / m, stamping is performed, a grid-like iron frame is removed, and the stamp material is further removed.
The stamp was put with a thickness of 00 m / m. The stamp material used was trade name AH-NN25 (MgO: 77.0%, Ca
O: 18.0%, Fe ₂ O ₃ : 3.8%, Al ₂ O ₃ :
0.3%, SiO ₂ : 0.6%). With the above repairs, re-operation was possible.

[0013]

As described above, according to the present invention, when the predetermined damage amount is reached, the pins are added and the irregular shaped refractory is filled to perform the repair on the way. The repair and the life of the furnace can be extended, and at the same time, the use cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram for explaining the addition of contact pins by spot welding.

FIG. 3 is a view for explaining another embodiment of adding contact pins.

FIG. 4 is a view showing an anode block of the DC arc furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Anode pin, 20 ... Grid iron frame, 21 ... Pipe, 22
... contact pins, 23 ... welding rods, 24 ... iron powder, 25 ...
Irregular refractories, 30 ... pipe, 31 ... iron powder or steel ball.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F27D 1/16 F27B 3/08 F27D 11/10 H05B 7/06

Claims (3)

(57) [Claims] In an anode block of a DC electric furnace using a fixed refractory or an irregular refractory, pipes having a diameter larger than the anode pins are attached to a grid-like iron frame, and the pipes are aligned with each anode pin. A DC electric furnace anode characterized by having a contact pin with a through hole inserted into it and standing on the anode pin head by spot welding, filling the joint between the anode pin and the contact pin with iron powder, and then filling it with an amorphous refractory. Block repair method. 2. An anode block of a DC electric furnace using a fixed refractory or an irregular refractory, wherein pipes having a diameter larger than the anode pins are attached to a grid-like iron frame and aligned with each anode pin. A contact pipe having a through-hole inserted therein is fitted or brought into contact with the anode pin head, and the contact pipe is filled with iron powder and / or iron balls, and then filled with irregular-shaped refractories. Furnace anode block repair method. 3. The method according to claim 1, wherein
A method for repairing an anode block of a DC electric furnace, wherein the repair is performed when the anode block is damaged by a predetermined amount, thereby making it possible to repair the furnace in a planned manner.