Protection structure for refractory bricks in electric furnace

Abstract

The utility model relates to a protection structure for refractory bricks in an electric furnace, which comprises a furnace body and magnesia carbon bricks mounted in the furnace body, and further comprises a magnetism isolating plate which is arranged in the furnace body and covers the outer surfaces of the magnesia carbon bricks, the utility model solves the problems that when the existing steel is smelted, different molten steel corrodes the refractory material on the furnace wall, so that the repair is required to be frequently missed in the midway, even the furnace is required to be offline, the corroded refractory material is replaced by a new refractory material, and the service life of the refractory material is short.

Description

Technical Field

[0001] The utility model relates to the technical field of electric furnaces, in particular to a protective structure for refractory bricks in an electric furnace. Background Art

[0002] Electric furnace steelmaking mainly utilizes arc heat. In the arc action zone, the temperature is as high as 4000℃. The smelting process is generally divided into melting period, oxidation period and reduction period. Not only can an oxidizing atmosphere be created in the furnace, but also a reducing atmosphere. Therefore, the efficiency of dephosphorization and desulfurization is very high. This type of steelmaking furnace, that is, electric furnace, includes electric arc furnace, induction furnace, electric slag furnace, electron beam furnace, consumable arc furnace, etc. Electric furnace steel is usually produced in an alkaline electric arc furnace. Due to the arc action zone of electric furnace steelmaking, the temperature can be as high as 4000℃, and the requirements for refractory bricks are very high.

[0003] The patent document with patent number CN111302830B discloses a method for preparing microporous high-temperature resistant lightweight refractory bricks, which relates to the technical field of refractory bricks. The microporous high-temperature resistant lightweight refractory bricks use refractory-grade alumina powder, polycrystalline mullite fiber and silicon powder as ceramic aggregates, carbonized rice husk as a pore-forming agent, water as a solvent, silica aerogel as a binder, sodium carboxymethyl cellulose solution as a foam stabilizer, ammonium salt solution as a dispersant, K12 powder as a foaming agent, and agar powder as a molding agent.

[0004] However, in actual use, the inventor discovered that when existing steel was smelted, different molten steels corroded the refractory materials on the furnace wall. Therefore, frequent repairs were required during the process, and the furnace might even need to be taken offline to replace the corroded refractory materials with new ones, resulting in a short service life of the refractory materials. Utility Model Content

[0005] The purpose of the utility model is to address the deficiencies of the prior art. By arranging a magnetic isolation plate close to the position of the furnace body transformer, the magnetic isolation plate at this position has no effect on the molten magnetism of the ladle, and the arc goes from above. The magnetic isolation plate and the magnetic field repel each other with the same polarity, blocking the magnetic field from passing through the magnesium carbon bricks, thereby avoiding the magnetic field from destroying the structure of the magnesium carbon bricks themselves, thereby solving the technical problems of frequent missed repairs or even the need to take the furnace offline to replace the corroded refractory with a new refractory, resulting in a short service life of the refractory.

[0006] In response to the above technical problems, the following technical solutions are adopted: a protective structure for refractory bricks in an electric furnace, including a furnace body and magnesia-carbon bricks installed in the furnace body, and also including a magnetic insulation plate built into the furnace body and coated on the outer surface of the magnesia-carbon bricks.

[0007] Preferably, the magnetic isolation plate is detachably installed in the furnace body.

[0008] Preferably, the magnetic isolation plate is welded and installed in the furnace body.

[0009] Preferably, the magnetic isolation plate has a thickness of 2-3 cm.

[0010] Preferably, the magnetic isolation plate is installed close to the transformer of the furnace body.

[0011] Preferably, the outer wall surface of the magnetic isolation plate is provided with uniform concave and convex parts.

[0012] As another preferred embodiment, the magnetic isolation plate is made of stainless steel.

[0013] Beneficial effects of the utility model:

[0014] (1) In the utility model, the magnetic isolation plate is arranged close to the transformer of the furnace body. The magnetic isolation plate at this position has no effect on the molten magnetism of the steel ladle. The arc goes from the top. The magnetic isolation plate and the magnetic field repel each other with the same polarity, blocking the magnetic field from passing through the magnesia carbon bricks, thereby preventing the magnetic field from destroying the structure of the magnesia carbon bricks themselves, protecting the magnesia carbon bricks and increasing the life of the magnesia carbon bricks.

[0015] (2) In the utility model, a magnetic isolation plate is provided to affect the stability of the arc. The magnetic field can affect the movement of charged particles in the arc, causing the arc to rotate. As the magnetic field strength increases, the rotation radius and speed of the arc will also increase, thereby improving the stiffness and stability of the arc.

[0016] In summary, the equipment has the advantages of simple structure and protection of refractory materials, and is particularly suitable for the field of electric furnace technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a schematic diagram of the structure of the protective structure for refractory bricks in an electric furnace.

[0019] Figure 2 It is a cross-sectional schematic diagram of the protective structure for refractory bricks in an electric furnace.

[0020] Figure 3 It is a top view schematic diagram of the protective structure for refractory bricks in an electric furnace.

[0021] Figure 4 It is a schematic diagram of the structure with added magnetic isolation plate.

[0022] Figure 5 This is a schematic diagram of the main low-order harmonics of the 35kV bus. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present utility model are clearly and completely described below in conjunction with the accompanying drawings.

[0024] Embodiment 1

[0025] like Figures 1 to 3 As shown, a protective structure for refractory bricks in an electric furnace includes a furnace body 1 and magnesia-carbon bricks 2 installed in the furnace body 1 , and also includes a magnetic isolation plate 3 built into the furnace body 1 and coated on the outer surface of the magnesia-carbon bricks 2 .

[0026] It should be noted that the influence of the magnetic field on the arc is mainly reflected in: changing the shape and movement trajectory of the arc. By applying an external magnetic field, the movement and heating mode of the arc can be controlled. For example, applying a transverse magnetic field can make the arc deflect to one side, while an alternating magnetic field can make the arc swing at the same frequency, thereby widening the heating area.

[0027] Therefore, in the present application, a magnetic isolation plate 3 is provided to affect the stability of the arc. The magnetic field can affect the movement of charged particles in the arc, causing the arc to rotate. As the magnetic field strength increases, the rotation radius and speed of the arc will also increase, and the stiffness and stability of the arc will be improved.

[0028] It should be noted that the invention is not limited to electric furnaces, but also can be used in different furnace bodies such as converters and ladles.

[0029] Moreover, the analysis report of adding magnetic isolation plate in Zone 2 of 150t electric furnace is shown in the following table. Its theoretical principle is the influence of magnetic field on arc: 1. Magnetic field changes the shape and movement trajectory of arc; 2. Magnetic field affects the stability of arc; its reference sources are "Magnetic Field and Materials Science" and "Basic Principles of Electromagnetic Field".

[0030] Table 12# Area without erosion changes of furnace wall

[0031] Unit: mm

[0032]

[0033] Table 22# Area after installation of magnetic isolation plate furnace wall erosion changes

[0034] Unit: mm

[0035]

[0036] In summary, firstly, without the installation of magnetic isolation plate (Table 1), the furnace wall of zone 2# changes rapidly, the groove of zone 2# in the on-site tracking furnace is serious, and the safe furnace service life is 260-300 (without excavation and repair);

[0037] Secondly, after installing magnetic isolation plates (Table 2), the furnace wall in zone 2# changed stably. The on-site tracking of furnace conditions showed that the grooves in zone 2# were not obvious, and the safe furnace service life was 550-600 times.

[0038] Furthermore, after the installation of the magnetic isolation plate, the erosion of the furnace wall in Zone 2 stabilized and the furnace life was significantly improved.

[0039] Furthermore, the magnetic isolation plate 3 can be detachably installed in the furnace body 1 .

[0040] In this embodiment, the magnetic isolation plate 3 can be detachably installed in the furnace body 1, which is convenient for replacement and improves the service life of the equipment.

[0041] Furthermore, the magnetic isolation plate 3 is welded and installed in the furnace body 1 .

[0042] In this embodiment, the magnetic isolation plate 3 is welded and installed in the furnace body 1, so the installation and use are stable.

[0043] Furthermore, the magnetic isolation plate 3 has a thickness of 2-3 cm.

[0044] Furthermore, the magnetic isolation plate 3 is installed close to the transformer of the furnace body 1 .

[0045] It is worth mentioning that the existing magnetic field and the magnetic field of the magnesium carbon brick attract each other, that is, the magnetic field directly passes through the magnesium carbon brick and destroys the structure of the magnesium carbon brick itself.

[0046] In this embodiment, the magnetic isolation plate 3 is set close to the furnace transformer, and the magnetic isolation plate 3 at this position has no effect on the molten magnetism in the ladle. The arc goes from above, and the magnetic isolation plate 3 repels the magnetic field with the same polarity, thereby blocking the magnetic field from passing through the magnesium carbon bricks, thereby preventing the magnetic field from destroying the structure of the magnesium carbon bricks themselves, protecting the magnesium carbon bricks and increasing the life of the magnesium carbon bricks.

[0047] It should be noted that the transformer is at the upper end of the furnace, that is, position 2 in the experimental data. The current and magnetic field are the largest at position 2.

[0048] Further, if Figure 4 As shown, the magnetic isolation plate 3 is made of stainless steel.

[0049] It should be noted that the magnetic isolation plate 3 is made of stainless steel, which can not only withstand high temperatures but also play a demagnetizing role.

[0050] In this embodiment, the effect after adding the magnetic isolation plate 3 and putting it into production is as follows:

[0051] ①. The power factor is increased from the original 0.75-0.82 to above 0.96; ②. The voltage fluctuation is reduced from the maximum 15% to 3%; ③. The long-term flicker of 35kV bus is reduced from 3.3 to 0.56. The long-term flicker of 110kV bus is reduced from 1.06 to 0.76; ④. The three-phase voltage imbalance is reduced from 3.5% to about 0.5%, and the average value of negative sequence current is reduced from 300A to about 80A; ⑤. Figure 5 As shown in the figure, the main low-order harmonics of the 35kV busbar are significantly reduced. The 0.5th harmonic voltage is reduced by 66.6%, the 1.5th harmonic voltage is reduced by 63.2%, the 2.5th interharmonic voltage is reduced by 66.1%, and the 3.5th interharmonic voltage is reduced by 67.2%; ⑥ After the shielded furnace shell was put into operation, the average power-on heating time of each furnace of steel was shortened by 5%, and the average power consumption per ton of steel was reduced by 3.2%.

[0052] Embodiment 2

[0053] like Figure 4 As shown, the components identical or corresponding to those in the first embodiment are marked with the corresponding reference numerals in the first embodiment. For the sake of simplicity, only the differences from the first embodiment are described below. The second embodiment differs from the first embodiment in that:

[0054] Furthermore, the outer wall surface of the magnetic isolation plate 3 is provided with uniform concave and convex parts 31 .

[0055] In this embodiment, the outer wall surface of the magnetic isolation plate 3 is provided with uniform concave-convex portions 31, thereby improving the demagnetization and blocking effect of the stainless steel plate on the magnetic field.

[0056] In the description of the present invention, it should be understood that the terms "front and back", "left and right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the equipment or components referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the utility model.

[0057] Of course, in the present technical solution, those skilled in the art should understand that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0058] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art under the technical guidance of the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A protective structure for refractory bricks in an electric furnace, comprising a furnace body (1) and magnesia carbon bricks (2) installed in the furnace body (1), characterized in that: It also includes a magnetic isolation plate (3) which is built into the furnace body (1) and coated on the outer surface of the magnesia carbon brick (2).

2. A protective structure for refractory bricks in an electric furnace according to claim 1, characterized in that: The magnetic isolation plate (3) is detachably installed in the furnace body (1).

3. A protective structure for refractory bricks in an electric furnace according to claim 1, characterized in that: The magnetic isolation plate (3) is welded and installed in the furnace body (1).

4. A protective structure for refractory bricks in an electric furnace according to claim 2 or 3, characterized in that: The thickness of the magnetic isolation plate (3) is 2-3 cm.

5. A protective structure for refractory bricks in an electric furnace according to claim 2 or 3, characterized in that: The magnetic isolation plate (3) is installed close to the transformer of the furnace body (1).

6. A protective structure for refractory bricks in an electric furnace according to claim 2 or 3, characterized in that: The magnetic isolation plate (3) is made of stainless steel.

7. A protective structure for refractory bricks in an electric furnace according to claim 2 or 3, characterized in that: The outer wall surface of the magnetic isolation plate (3) is provided with uniform concave and convex portions (31).

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