A top sealing device for an ore thermal furnace for producing large-crystalline fused magnesite

Abstract

The present invention provides a furnace top sealing device for a submerged arc furnace for producing large-crystalline fused magnesite, which comprises a furnace cover, a furnace cover support ring, a steel seal cover and a flue gas outlet pipe. The furnace cover is installed in the middle of the furnace cover support ring, and the furnace cover support ring is fixed at the opening of the steel structure of the furnace top operation platform, directly above the furnace barrel of the submerged arc furnace. The steel seal cover covers the furnace cover support ring, completely restricting the furnace flue gas with a large amount of entrained dust rising during smelting within the cover. A flue gas outlet pipe and a feed pipe are provided on the steel seal cover, and electrode holes corresponding to three electrodes are provided on both the furnace cover and the steel seal cover. The present invention realizes the furnace top sealing of the submerged arc furnace for producing large-crystalline fused magnesite, realizes continuous centralized dust removal in a sealed environment, has a small dust removal power, saves electric power resources, improves the working environment of workers, and avoids the damage to the physical health of workers and even the infringement of their life safety in the traditional method where workers work on the furnace top operation platform.

Description

Technical Field

[0001] The present invention relates to a production device for large-crystalline fused magnesia, and particularly to a furnace top sealing device for a submerged arc furnace for producing large-crystalline fused magnesia. Background Art

[0002] Large-crystalline fused magnesia, due to its high purity, large crystal grains, high melting point, high hot crushing strength at high temperatures, good slag resistance and corrosion resistance, is used as the lining refractory material for steelmaking furnaces, and is also a high-quality and high-grade basic refractory raw material for manufacturing refractory bricks and unshaped refractory materials. It can also be used as a filler for making thermocouples and thermal insulation materials.

[0003] Large-crystalline fused magnesia is mainly prepared by smelting light-burned magnesia powder in a submerged arc furnace. First, above a steel cylindrical furnace shell, three graphite electrodes are inserted into the interior of the furnace shell. On the furnace top operation platform at the upper opening of the furnace shell, the furnace charge is dumped to the furnace bottom by means of manual shoveling and feeding, or feeding through a chute from a high-level storage bin. Current is introduced through the graphite electrodes to heat and melt the furnace charge between the electrodes.

[0004] During the production process, the furnace charge is continuously added, and the electric control system automatically controls the electrodes to gradually rise until the furnace body is filled, and finally a smelting cycle is completed. An open-type dust removal hood is provided above the furnace top operation platform, and dust removal is continuously carried out during the smelting process.

[0005] Disadvantages of the prior art: (1) In the method of feeding through a chute from a high-level storage bin, manual adjustment of the feeding position is required on the furnace top operation platform to ensure as uniform feeding as possible. Therefore, in the above feeding methods, workers are required to work on the furnace top operation platform.

[0006] (2) Due to the continuous addition of the furnace charge, dust will continuously rise. In addition, during the smelting process, the temperature of the furnace top operation platform will become extremely high due to the radiation of the heating electrodes. The presence of dust and high temperature makes the working environment of the furnace top operation platform extremely harsh, causing serious damage to the physical health of workers.

[0007] (3) In addition, during the smelting process, the furnace charge often splashes due to the upward spraying of high-pressure gas in the furnace charge, causing burns and scalds to the workers on the furnace top operation platform and even threatening their lives.

[0008] (4) Although a dust removal hood is provided above the furnace top operation platform, the height of the dust removal hood is more than 2m to ensure that workers can work on the furnace top operation platform. This dust removal method can ensure that the external environment of the workshop is not polluted by dust, but the working environment of workers has not been improved.

[0009] In addition, since the dust removal device continuously removes dust in an open environment, it requires a large amount of power, resulting in unnecessary waste of electric power resources. Summary of the Invention

[0010] The present invention provides a furnace top sealing device for a submerged arc furnace for producing large-crystalline fused magnesite, which is used to solve the problem of how to control the dust removal of the submerged arc furnace. For a furnace barrel with only one upper opening, heat prevention treatment is achieved without affecting the feeding. Effective dust removal and safe operation during the smelting process of the large-crystalline fused magnesite submerged arc furnace are realized, the working environment of workers is improved, the damage to the health of workers caused by the dust environment at the furnace top in the traditional method is avoided, and the infringement on the life safety of operating workers caused by the splashing accident of the furnace is also avoided. The technical solution is as follows:

[0011] A furnace top sealing device for a submerged arc furnace for producing large-crystalline fused magnesite includes a furnace cover, a furnace cover support ring, a steel seal cover and a flue gas outlet pipe. The furnace cover is installed in the middle of the furnace cover support ring. The furnace cover support ring is fixed at the opening of the steel structure of the furnace top operation platform, directly above the furnace barrel of the submerged arc furnace. The steel seal cover covers the furnace cover support ring, completely restricting the flue gas in the furnace with a large amount of dust rising during smelting within the cover. A flue gas outlet pipe and a feeding pipe are provided on the steel seal cover, and electrode holes corresponding to three electrodes are provided on both the furnace cover and the steel seal cover.

[0012] The furnace cover includes an integrally formed upper cover and a lower cover. The upper cover is cylindrical, and the lower cover is conical.

[0013] The furnace cover support ring includes an inner ring, steel ribs and an outer ring. The inner ring and the outer ring are connected by steel ribs. The annular gap formed between the inner ring and the outer ring is used for furnace charge to flow into the furnace barrel and the flue gas in the furnace barrel to rise and discharge. The top of the outer ring extends horizontally outward to form an annular plate for fixing at the opening of the steel structure of the furnace top operation platform.

[0014] The inner ring is arranged as a conical cylinder and has the same taper as the lower cover of the furnace cover for installing the matching furnace cover.

[0015] The connecting ribs 22 are set to be 6 - 12 and are evenly distributed along the circumference.

[0016] The steel seal cover includes a barrel wall and an end sealing plate. One end of the barrel wall is sealed by the end sealing plate, and the other end is open. The end sealing plate is provided with a seal cover electrode hole and a flue gas outlet pipe, and the flue gas outlet pipe is connected to the dust removal pipeline.

[0017] The barrel wall is divided into an inner barrel and an outer barrel. The inner barrel and the outer barrel form a double-layer sidewall cylinder, and an annular gap is formed between the double-layer cylinders. The upper ends of the inner barrel and the outer barrel are sealed by the end sealing plate, and the lower ends are completely open. The inner barrel is provided with openings.

[0018] The annular gap of the steel seal cover corresponds to the annular gap of the furnace cover support ring. The flue gas outlet pipe is within the range of the inner barrel, and the feeding pipe enters the annular gap and reaches above the annular gap of the furnace cover support ring for feeding.

[0019] There are 10 - 20 openings left along the circumference at the position of the inner cylinder near the end sealing plate, and the shapes of the openings are rectangular or round holes.

[0020] The diameter of the inner cylinder is the same as that of the furnace cover, and the diameter of the outer cylinder is 200 - 600 mm larger than that of the inner cylinder.

[0021] The present invention realizes the top sealing of the shaft furnace for producing large-crystalline fused magnesite, realizes continuous centralized dust removal in a sealed environment, has small dust removal power, saves electric power resources, and at the same time improves the working environment of workers, avoiding the damage to their physical health and even the infringement of life safety caused by workers working on the top operation platform of the furnace in the traditional method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the explosion structure schematic diagram of the top sealing device of the shaft furnace for producing large-crystalline fused magnesite;

[0023] Figure 2 is the schematic diagram of the use state of the top sealing device of the shaft furnace for producing large-crystalline fused magnesite;

[0024] Figure 3 is the sectional structure schematic diagram of the top sealing device of the shaft furnace for producing large-crystalline fused magnesite;

[0025] Figure 4 is the structure schematic diagram of the furnace cover;

[0026] Figure 5 is the structure schematic diagram of the furnace cover support ring;

[0027] Figure 6 is the sectional structure schematic diagram of the steel seal cover;

[0028] Figure 7 is the opening schematic diagram of the steel seal cover;

[0029] Each label in the figure:

[0030] 1 - furnace cover; 2 - furnace cover support ring; 3 - steel seal cover; 4 - flue gas outlet pipe; 5 - feed pipe; 11 - upper cover; 12 - lower cover; 13 - furnace cover electrode hole; 21 - inner ring; 22 - rib plate; 23 - outer ring; 24 - annular plate; 31 - inner cylinder; 32 - outer cylinder; 33 - opening; 34 - end sealing plate; 35 - seal cover electrode hole. DETAILED DESCRIPTION OF THE INVENTION

[0031] As Figures 1 to 3As shown in the figure, the furnace top sealing device of the submerged arc furnace for producing large crystal fused magnesia includes a furnace cover 1, a furnace cover support ring 2, a steel seal cover 3, and a flue gas outlet pipe 4. The furnace cover 1 is installed in the middle of the furnace cover support ring 2. The furnace cover support ring 2 is fixed at the opening of the steel structure of the furnace top operation platform, directly above the furnace barrel of the submerged arc furnace. The steel seal cover 3 covers the furnace cover support ring 2. A flue gas outlet pipe 4 and a feed pipe 5 are arranged on the steel seal cover 3. Electrode holes are arranged on both the furnace cover 1 and the steel seal cover 3.

[0032] As Figure 4 shown in the figure, the furnace cover 1 is made of refractory material, and the refractory material is magnesia dense refractory material.

[0033] The furnace cover 1 is used to cover the open furnace barrel opening. It includes an integrally formed upper cover 11 and a lower cover 12. The upper cover 11 is cylindrical, and the lower cover 12 is conical. Three through furnace cover electrode holes 13 are arranged on the furnace cover 1. The diameter of the furnace cover electrode holes 13 is slightly larger than the electrode diameter, so that when the electrode extends into the furnace barrel through the furnace cover electrode holes 13, its up and down movement is not affected.

[0034] As Figure 5 shown in the figure, the furnace cover support ring 2 adopts a double-layer cylinder structure of inner and outer rings, including an inner ring 21, steel ribs 22, and an outer ring 23.

[0035] The inner ring 21 can be set as a conical cylinder, and has the same taper as the lower cover 12 of the furnace cover 1, for installing the matching furnace cover 1.

[0036] The inner ring 21 and the outer ring 23 of the furnace cover support ring 2 are connected by steel ribs 22. The connecting ribs 22 are set to 6 - 12 pieces, and are evenly distributed along the circumference.

[0037] The annular gap formed between the inner ring 21 and the outer ring 23 is used for furnace charge to flow into the furnace barrel and the flue gas in the furnace barrel to rise and discharge.

[0038] The top of the outer ring 23 of the furnace cover support ring 2 extends horizontally outwards to form an annular plate 24, for placing at the opening of the steel structure of the furnace top operation platform.

[0039] As Figures 6 to 7 shown in the figure, the steel seal cover 3 is provided with a seal cover electrode hole 35, a flue gas outlet pipe 4, and a feed pipe 5. The steel seal cover 3 includes a barrel wall and an end sealing plate 34. The end sealing plate 34 is provided with a seal cover electrode hole 35 and a flue gas outlet pipe 4. The function of the seal cover 3 is to ensure that the furnace gas rising from the circumferential gap of the furnace cover support ring 2 is completely covered in the annular space of the seal cover 3.

[0040] Three cover electrode holes 35 of the same size are arranged in the middle of the upper part of the end cover plate 34. The diameter of the cover electrode holes 35 is slightly larger than the diameter of the electrode, so that when the electrode extends into the furnace barrel through the furnace cover electrode hole 13, its up and down movement is not affected. The cover electrode holes 35 are arranged corresponding to the openings of the furnace cover electrode holes 13 for the electrode to pass through.

[0041] Further, near the cover electrode holes 35, a flue gas outlet pipe 4 is arranged. The flue gas outlet pipe 4 is connected to a dust removal device, and the dust is discharged through the fan of the dust removal device.

[0042] The feed pipe 5 passes through the steel cover 3 and reaches above the annular gap of the furnace cover support ring 2 for feeding. Corresponding feed ports can also be arranged at the annular gaps of the furnace cover support ring 2, so that the lower end of the feed pipe 5 is connected with the feed ports in a matching manner, and the material directly reaches the furnace barrel through the feed ports.

[0043] At this time, the exhaust of the flue gas outlet pipe 4 will cause an air flow response near the pipe orifice. The furnace cover electrode holes 13, the cover electrode holes 35, and the annular gap of the furnace cover support ring 2 will all convey air flow to the flue gas outlet pipe 4. When the furnace cover electrode holes 13, the cover electrode holes 35, and the electrode are closely matched, the annular gap of the furnace cover support ring 2 will send the floating dust to the flue gas outlet pipe 4.

[0044] Since the dust is formed by the material in the feeding process being impacted by the air flow in the furnace barrel, directly discharging it through the dust removal device will cause loss of raw materials. Therefore, the flow direction of the air flow can be controlled.

[0045] The barrel wall is arranged in two layers. In this way, the steel cover 3 includes an inner cylinder 31, an outer cylinder 32, and an end cover plate 34. The inner cylinder 31 and the outer cylinder 32 form a side-wall double-layer cylinder, and an annular gap is formed between the double-layer cylinders. The upper ends of the inner cylinder 31 and the outer cylinder 32 are sealed by the end cover plate 34, and the lower ends are completely open.

[0046] At the position where the inner cylinder 31 is close to the end cover plate 34, 10 - 20 openings 33 are left along the circumference to allow the flue gas in the annular gap to enter the inner cylinder 31. The shape of the openings 33 can be rectangular or round holes. The flue gas outlet pipe 4 is within the range of the inner cylinder 31. The diameter of the inner cylinder 31 is equal to the diameter of the furnace cover 1, and the diameter of the outer cylinder 32 is 200 - 600 mm larger than the diameter of the inner cylinder 31. The installation method of the cover 3 is that the end cover plate 34 of the cover 3 is on the top and the opening is downward, and the cover 3 completely covers the annular gap of the furnace cover support ring 2.

[0047] The circumferential seam of the steel cover 3 corresponds to the annular gap of the furnace cover support ring 2. Then, the outer cylinder 32 is not less than the coverage range of the outer ring 23 of the furnace cover support ring 2, and the inner cylinder 31 is not greater than the coverage range of the inner ring 21 of the furnace cover support ring 2. The feed pipe 5 provided on the steel cover 3 enters the circumferential seam of the steel cover 3, and reaches above the annular gap of the furnace cover support ring 2 below the feed pipe 5 for feeding.

[0048] The setting method of using the outer cylinder 32 and the inner cylinder 31, compared with only using a single-layer cylinder wall, lies in that the dust suction wind pressure can be equalized. Because the circumferential seam of the steel cover 3 corresponds to the annular gap of the furnace cover support ring 2, the dust rising from the furnace cover electrode hole 13 needs to pass through the circumferential seam of the steel cover 3 from bottom to top, enter the range of the inner cylinder 31 from the opening 33, and then the dust enters the dust removal device from the flue gas outlet pipe 4. In this way, by controlling the air flow direction, not only the furnace flue gas with a large amount of entrained dust rising during smelting is completely restricted within the cover 3, but also the dust is not directly discharged, thus saving raw materials.

[0049] Embodiment:

[0050] In one of the embodiments, the furnace cover support ring 2 has a double-layer cylinder structure of inner and outer rings. The diameter of the outer ring 23 is 1500 mm, the inner ring 21 is a conical cylinder structure, with an upper diameter of 1300 mm and a lower diameter of 1200 mm. The size of the furnace cover 1 matches the size of the inner ring 21, and the furnace cover 1 is made of magnesia refractory material with a MgO content ≥ 80%. The inner and outer rings of the furnace cover support ring 2 are evenly connected by 12 steel connecting rib plates 22.

[0051] The structure of the cover 3 is a barrel-shaped structure with a double-layer side wall and a single-layer top closure. The diameter of the inner cylinder 31 is 1300 mm, the diameter of the outer cylinder 32 is 1500 mm. There are 12 openings opened on the circumference of the inner cylinder near the end sealing plate 34, and the opening size is 150 mm × 150 mm. There are three openings with a diameter slightly larger than the electrode diameter left in the middle of the end sealing plate 34.

[0052] The end sealing plate 34 is provided with a flue gas outlet pipe 4, and the flue gas outlet pipe 4 is connected to the dust removal pipeline of the dust removal device.

[0053] The present invention realizes the furnace top sealing of the ore thermal furnace for producing large-crystalline fused magnesia, realizes continuous centralized dust removal in a sealed environment, has a small dust removal power, saves electric power resources, and at the same time improves the working environment of workers, avoiding the damage to their physical health and even the infringement of life safety caused by workers working on the furnace top operation platform in the traditional method.

Claims

1. A top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite, characterized in that: It includes a furnace cover, a furnace cover support ring, a steel seal cover and a flue gas outlet pipe. The furnace cover is installed in the middle of the furnace cover support ring. The furnace cover support ring is fixed at the opening of the steel structure of the top operating platform, directly above the shell of the submerged-arc furnace. The steel seal cover covers the furnace cover support ring, completely restricting the flue gas in the furnace with a large amount of dust rising during smelting within the cover. A flue gas outlet pipe and a feed pipe are provided on the steel seal cover, and electrode holes corresponding to three electrodes are provided on both the furnace cover and the steel seal cover; The steel seal cover includes a barrel wall and an end sealing plate. One end of the barrel wall is sealed by the end sealing plate, and the other end is open. The end sealing plate is provided with seal cover electrode holes and a flue gas outlet pipe, and the flue gas outlet pipe is connected to the dust removal pipeline; The furnace cover support ring includes an inner ring, steel ribs and an outer ring. The inner ring and the outer ring are connected by steel ribs. The annular gap formed between the inner ring and the outer ring is used for furnace charge to flow into the furnace shell and the flue gas in the furnace shell to rise and discharge; The top of the outer ring extends horizontally outwards to form an annular plate for fixing at the opening of the steel structure of the top operating platform; The barrel wall is divided into an inner barrel and an outer barrel. The inner barrel and the outer barrel form a double-layer cylindrical side wall. An annular gap is formed between the double-layer cylinders. The upper ends of the inner barrel and the outer barrel are sealed by the end sealing plate, and the lower ends are completely open. The inner barrel is provided with openings; The annular gap of the steel seal cover corresponds to the annular gap of the furnace cover support ring. The flue gas outlet pipe is within the range of the inner barrel. The feed pipe enters the annular gap and reaches above the annular gap of the furnace cover support ring for feeding.

2. The top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite according to claim 1, characterized in that: The furnace cover includes an integrally formed upper cover and a lower cover. The upper cover is cylindrical, and the lower cover is conical.

3. The top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite according to claim 1, characterized in that: The inner ring is arranged as a conical cylinder and has the same taper as the lower cover of the furnace cover for installing a matching furnace cover.

4. The top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite according to claim 1, characterized in that: The connecting ribs are set to 6 to 12 and are evenly distributed along the circumference.

5. The top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite according to claim 1, characterized in that: At the position of the inner barrel close to the end sealing plate, 10 to 20 openings are left along the circumference, and the shape of the openings is rectangular or round.

6. The top sealing device for a submerged-arc furnace for producing large-crystalline fused magnesite according to claim 1, characterized in that: The diameter of the inner barrel is the same as the diameter of the furnace cover, and the diameter of the outer barrel is 200 to 600 mm larger than the diameter of the inner barrel.

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