Furnace bottom masonry structure of direct current submerged arc furnace and direct current submerged arc furnace
By using multi-layered refractory bricks laid in a staggered manner and graphite electrodes arranged at an angle, the reliability and stability of the furnace bottom of the DC submerged arc furnace were solved, achieving leak-proof molten iron and uniform current conduction, thus improving production safety and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NING XIA NING PING TAN SU YOU XIAN ZE REN GONG SI
- Filing Date
- 2025-05-09
- Publication Date
- 2026-05-15
AI Technical Summary
The furnace bottom lining structure of traditional DC submerged arc furnaces is difficult to guarantee reliability, safety and stability under multi-electrode layout, resulting in molten iron leakage and uneven electrode stress, which affects production safety and efficiency.
The multi-layer refractory bricks are laid in a staggered manner, with the graphite electrodes concentrated in the center of the furnace bottom and forming an angled layout. Combined with low thermal conductivity refractory bricks and carbonaceous binder, the structural sealing and current uniformity are enhanced.
It effectively prevents molten iron leakage, improves electrical energy conversion efficiency, extends electrode life, enhances furnace stability and safety, and reduces maintenance costs.
Smart Images
Figure CN224246744U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electric arc furnace technology, specifically to a furnace bottom lining structure and a DC electric arc furnace. Background Technology
[0002] As a core piece of equipment in the metallurgical and chemical industries, the DC submersible arc furnace significantly improves production efficiency thanks to the high-efficiency heating and stable operation advantages of the DC arc. Its bottom electrodes are mostly made of graphite, requiring them to penetrate the furnace body for current conduction, a design challenge that presents a challenge to the furnace bottom structure.
[0003] In traditional bricklaying processes, the straight, horizontal and vertical refractory brick laying method, with its orderly staggered joint design, enhances structural stability and ensures a neat appearance of the furnace bottom, effectively guaranteeing its service life under normal conditions. However, when faced with the multi-directional bottom electrode layout of a DC submerged arc furnace, especially in complex situations with three or more electrodes, the limitations of this traditional bricklaying method become apparent. Due to the increased number of bottom electrodes, the refractory bricks must be arranged irregularly around them, completely disrupting the original neat brick joint system, resulting in numerous overlapping gaps. This situation significantly increases the channels for molten iron leakage. Once high-temperature molten iron penetrates the furnace bottom, it will not only directly damage the furnace bottom structure but also force the production line to shut down, potentially even causing serious safety accidents. Therefore, it is clear that traditional bricklaying techniques are no longer sufficient to meet the reliability, safety, and stability requirements of the furnace bottom in a DC submerged arc furnace. Utility Model Content
[0004] To address the technical problem of low reliability, safety, and stability of the furnace bottom lining structure in DC-DC submerged arc furnaces, the present invention aims to provide a furnace bottom lining structure and a DC-DC submerged arc furnace. The specific technical solution adopted is as follows:
[0005] A bottom lining structure for a DC submerged arc furnace includes: multiple layers of refractory bricks, each layer being constructed sequentially from bottom to top along the axial direction of the furnace body; the gaps between adjacent refractory bricks in each layer and between refractory bricks in adjacent layers are staggered; the bottom layer of refractory bricks is laid flat on the bottom of the DC submerged arc furnace, and multiple graphite electrodes of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks, with one end of each graphite electrode converging at the center of the bottom, and the other end of each graphite electrode extending out of the furnace body, with adjacent graphite electrodes forming an angle; the remaining refractory brick layers are constructed sequentially from bottom to top along the axial direction of the DC submerged arc furnace and located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrodes, with the upper surface of the graphite electrodes at a height higher than the top layer of refractory bricks, so as to separate the molten liquid near the bottom of the DC submerged arc furnace through the graphite electrodes.
[0006] Optionally, each graphite electrode includes a graphite electrode body and a low thermal conductivity refractory brick. One end of the graphite electrode body is fixedly connected to one end of the low thermal conductivity refractory brick. The other end of the graphite electrode body is not located inside the DC submerged arc furnace. Each graphite electrode of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer. The other ends of each low thermal conductivity refractory brick are spliced together in a radial layout. The low thermal conductivity refractory brick is used to prevent heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body.
[0007] Optionally, the graphite electrode body and the low thermal conductivity refractory bricks are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each low thermal conductivity refractory brick are spliced and contacted with each other are also bonded and fixed together using a ceramic adhesive.
[0008] Optionally, the gaps between the refractory bricks in each layer of refractory bricks are filled with carbonaceous binder, and the parts of the inner side wall of the DC submerged arc furnace that contact the refractory bricks and the parts of the outer side wall of the graphite electrode that contact the refractory bricks are also filled with carbonaceous binder.
[0009] Optionally, the refractory brick layer includes three layers, with different construction methods for adjacent refractory brick layers. The bottom and top refractory brick layers are constructed using the first construction method, while the middle refractory brick layers are constructed using the second construction method. The first construction method is a parallel arrangement, in which one of the graphite electrodes is used as a reference electrode, and the long sides of the refractory bricks are arranged sequentially with the reference electrode perpendicular to the long side. The second construction method is a radial arrangement, in which the long sides of the refractory bricks are arranged sequentially with the long sides pointing towards the central axis of the DC submerged arc furnace.
[0010] A DC submerged arc furnace includes: a furnace bottom lining structure comprising multiple graphite electrodes and the furnace bottom lining structure described in the above embodiments; each layer of refractory bricks in the furnace bottom lining structure is laid sequentially from bottom to top along the axial direction of the furnace body; the gaps between adjacent refractory bricks in each refractory brick layer and between refractory bricks in adjacent refractory brick layers are staggered; the bottom layer of refractory bricks is laid flat on the furnace bottom of the DC submerged arc furnace, and the multiple graphite electrodes of the DC submerged arc furnace are placed on the bottom layer of refractory bricks. On the surface, one end of each graphite electrode converges at the center of the furnace bottom, and part of the other end of each graphite electrode extends out of the furnace body of the DC submerged arc furnace, with an angle between adjacent graphite electrodes; the remaining refractory brick layers are built sequentially from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrodes. The height of the upper surface of the graphite electrodes is higher than the height of the topmost refractory brick layer, so as to separate the molten liquid near the furnace bottom in the DC submerged arc furnace through the graphite electrodes.
[0011] Optionally, each graphite electrode includes a graphite electrode body and a low thermal conductivity refractory brick. One end of the graphite electrode body is fixedly connected to one end of the low thermal conductivity refractory brick. The other end of the graphite electrode body is not located inside the DC submerged arc furnace. Each graphite electrode of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer. The other ends of each low thermal conductivity refractory brick are spliced together in a radial layout. The low thermal conductivity refractory brick is used to prevent heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body.
[0012] Optionally, the graphite electrode body and the low thermal conductivity refractory bricks are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each low thermal conductivity refractory brick are spliced and contacted with each other are also bonded and fixed together using a ceramic adhesive.
[0013] Optionally, the gaps between the refractory bricks in each layer of refractory bricks are filled with carbonaceous binder, and the parts of the inner side wall of the DC submerged arc furnace that contact the refractory bricks and the parts of the outer side wall of the graphite electrode that contact the refractory bricks are also filled with carbonaceous binder.
[0014] Optionally, the refractory brick layer includes three layers, with different construction methods for adjacent refractory brick layers. The bottom and top refractory brick layers are constructed using the first construction method, while the middle refractory brick layers are constructed using the second construction method.
[0015] The first construction method is a parallel arrangement, in which one of the graphite electrodes is used as the reference electrode, and the refractory bricks are arranged in sequence with their long sides perpendicular to the reference electrode. The second construction method is a radial arrangement, in which the long sides of the refractory bricks are arranged in sequence with their long sides pointing towards the central axis of the DC submerged arc furnace.
[0016] This utility model discloses a furnace bottom construction structure for a DC submerged arc furnace, comprising: multiple layers of refractory bricks, each layer being constructed sequentially from bottom to top along the axial direction of the furnace body; the gaps between adjacent refractory bricks in each layer and between refractory bricks in adjacent layers are staggered; the bottom layer of refractory bricks is laid flat on the furnace bottom of the DC submerged arc furnace, and multiple graphite electrodes of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks, with one end of each graphite electrode located on the furnace bottom. The graphite electrodes converge at the center, with a portion of the other end of each graphite electrode extending out of the furnace body and forming an angle between adjacent graphite electrodes; the remaining refractory brick layers are laid sequentially from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrodes. The height of the upper surface of the graphite electrodes is higher than the height of the topmost refractory brick layer, so as to separate the molten liquid near the bottom of the DC submerged arc furnace through the graphite electrodes.
[0017] Thus, this embodiment of the invention solves the drawback of stress concentration paths caused by aligned gaps in traditional single-laying methods by employing different construction methods for adjacent refractory brick layers and staggered gaps. Furthermore, the staggered gaps between refractory bricks and the staggered layout between gaps in adjacent refractory brick layers significantly increase the path length and difficulty for gas and liquid media to penetrate. During the smelting process, this effectively prevents high-temperature flue gas and molten metal from leaking through the gaps in the furnace bottom, reducing the risk of insulation material corrosion and maintaining good insulation performance of the furnace body. Simultaneously, good sealing helps maintain a stable smelting atmosphere inside the furnace, preventing impurities such as air from entering and affecting the smelting reaction, thus ensuring the production of high-quality products. The arrangement of multiple graphite electrodes with one end concentrated at the center of the furnace bottom and the other end partially extending out of the furnace body at a predetermined angle ensures more uniform stress on the electrodes during smelting, avoiding the arcing and arc-breaking phenomena caused by uneven stress on the electrodes in traditional layouts. This ensures stable current conduction and improves energy conversion efficiency. Meanwhile, by dividing the furnace bottom space into multiple areas using graphite electrodes, the oscillation amplitude of molten iron at the furnace bottom is reduced, thereby decreasing the scouring effect of the molten iron on the bottom electrodes and extending their lifespan. Therefore, when this embodiment of the invention constructs the furnace bottom of a DC submerged arc furnace using the above-mentioned method, the reliability, safety, and stability of the furnace bottom are improved. Furthermore, the refractory brick layer in this area further reinforces the furnace structure, providing a stable support environment for the graphite electrodes and enhancing the stability of the graphite electrodes within the furnace as well as the overall stability of the furnace system. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the furnace bottom lining structure of a DC submerged arc furnace disclosed in an embodiment of the present utility model;
[0019] Figure 2 This is a schematic diagram of a refractory brick layer constructed by a first masonry method, comprising a bottom layer and an top layer of refractory bricks, as disclosed in an embodiment of this utility model.
[0020] Figure 3 This is a schematic diagram of a refractory brick layer with an intermediate layer constructed using a second masonry method, as disclosed in an embodiment of this utility model.
[0021] Figure 4 This is a schematic diagram of the structure of a graphite electrode and the structure between the graphite electrode and the refractory brick layer disclosed in an embodiment of the present invention. Detailed Implementation
[0022] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a furnace bottom lining structure and a direct-current submerged arc furnace according to this utility model. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.
[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0024] The following description, in conjunction with the accompanying drawings, details the furnace bottom construction structure and specific scheme of the DC submerged arc furnace provided by this utility model.
[0025] like Figure 1 As shown, Figure 1 This is a schematic diagram of the furnace bottom masonry structure of a DC submerged arc furnace disclosed in an embodiment of the present invention. The furnace bottom masonry structure includes: multiple layers of refractory bricks 101, each layer of refractory bricks 101 being laid sequentially from bottom to top along the axial direction of the furnace body 102 of the DC submerged arc furnace; the gaps between adjacent refractory bricks in each layer of refractory bricks 101 and between refractory bricks in adjacent layers of refractory bricks 101 are staggered; the bottom layer of refractory bricks 101 is laid flat on the furnace bottom of the DC submerged arc furnace, and multiple graphite electrodes 103 of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks 101, with each graphite electrode 103... One end of each graphite electrode 103 converges at the center of the furnace bottom, and a portion of the other end of each graphite electrode 103 extends out of the furnace body 102 of the DC submerged arc furnace, with adjacent graphite electrodes 103 forming an angle. The remaining refractory brick layers 101 are sequentially built from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner side wall of the furnace body 102 and the outer side wall of the graphite electrodes 103. The height of the upper surface of the graphite electrodes 103 is higher than the height of the topmost refractory brick layer 101, so as to separate the molten liquid near the furnace bottom in the DC submerged arc furnace through the graphite electrodes 103.
[0026] Specifically, in this embodiment of the invention, the bottom layer of the furnace body 102 is covered with refractory bricks. After the bottom layer of refractory bricks 101 is completed, multiple graphite electrodes 103 of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks 101. One end of each graphite electrode 103 is concentrated at the center of the furnace bottom, and the other end of each graphite electrode 103 is not inside the DC submerged arc furnace, with adjacent graphite electrodes 103 forming an angle. To enhance the structural strength and sealing of the furnace body 102, adjacent refractory brick layers 101 are constructed using different methods. One layer of adjacent refractory bricks 101 can be constructed using a staggered flat-lay method, arranging the refractory bricks horizontally with the long side joints of adjacent refractory bricks staggered. The other layer of refractory bricks 101 can be constructed using a header-lay method, arranging the refractory bricks vertically, forming a crisscross structure between adjacent refractory brick layers 101. In this way, the gaps between the refractory bricks in adjacent refractory brick layers 101 are staggered, effectively avoiding stress concentration and the problem of molten iron penetrating through the gaps, thus enhancing the furnace body 102's resistance to high temperature, high pressure, and chemical corrosion. Furthermore, one of the adjacent refractory brick layers 101 can be arranged in a parallel pattern, while the other refractory brick layer 101 can be arranged radially.
[0027] Furthermore, within the same refractory brick layer 101, the gaps between each refractory brick also follow the staggered principle. During the construction process, the position of the refractory bricks and the width of the gaps are precisely controlled, and the staggered width between the gaps is determined according to the size of the refractory bricks. This forces gaseous and liquid media to travel a longer and more tortuous path when permeating through the gaps, preventing molten iron from directly flowing down to the bottom of the furnace through the through gaps. This effectively prevents high-temperature flue gas and molten metal from leaking through the gaps, protecting the internal structure of the furnace bottom.
[0028] Furthermore, after completing the construction of the bottom refractory brick layer 101 at the furnace bottom, the graphite electrodes 103 are installed. Multiple graphite electrodes 103 are neatly placed on the upper surface of the bottom refractory brick layer 101, with one end of each electrode converging at the center of the furnace bottom to form a convergence point, and the other end partially extending outwards from the DC submerged arc furnace, forming an outward-radiating layout. A specific angle is maintained between adjacent graphite electrodes 103 (e.g., 30° - 60°, the specific angle being determined based on the diameter of the furnace body 102 and the number of graphite electrodes 103). This layout ensures a more uniform current distribution when the graphite electrodes 103 are energized, effectively avoiding problems such as arc deviation and arc breakage, ensuring arc stability, and improving energy conversion efficiency.
[0029] Furthermore, in the area enclosed by the inner wall of the furnace body 102 of the DC submerged arc furnace and the outer wall of the graphite electrode 103, multiple layers of refractory bricks 101 are continuously built upwards, such that the remaining refractory brick layers 101 are built sequentially from bottom to top along the axial direction of the DC submerged arc furnace and located in the area enclosed by the inner wall of the furnace body 102 and the outer wall of the graphite electrode 103. During the building process, the height of the refractory brick layers 101 is strictly controlled to ensure that the height of the upper surface of the graphite electrode 103 is always higher than the height of the topmost refractory brick layer 101. For example, from... Figure 1 As can be seen, the refractory brick layer 101 is located inside the furnace body 102, and its total height is lower than that of the graphite electrode 103. This allows the graphite electrode 103 to better contact the materials inside the furnace during the smelting process, while preventing the refractory brick layer 101 from obstructing the graphite electrode 103, ensuring that the electric arc can fully act on the materials. Furthermore, the refractory brick layer 101 in this area further reinforces the structure of the furnace body 102, providing a stable support environment for the graphite electrode 103, enhancing the stability of the graphite electrode 103 within the furnace and the overall stability of the furnace body 102 system.
[0030] Furthermore, as an optional embodiment of this utility model, the refractory brick layer 101 includes three layers, and the adjacent refractory brick layers 101 are constructed in different ways. The bottom layer refractory brick layer 101 and the top layer refractory brick layer 101 are constructed in a first construction method, and the middle layer refractory brick layer 101 is constructed in a second construction method. The first construction method is a parallel arrangement, in which one of the graphite electrodes 103 is used as a reference electrode, and the long side of the refractory bricks is arranged and constructed in sequence with the long side of the refractory bricks perpendicular to the reference electrode. The second construction method is a radial arrangement, in which the long side of the refractory bricks is arranged and constructed in sequence with the long side of the refractory bricks pointing towards the central axis of the DC submerged arc furnace.
[0031] Specifically, such as Figure 2 and Figure 3 As shown, Figure 2 This is a schematic diagram of a refractory brick layer constructed by a first masonry method, comprising a bottom layer and an top layer of refractory bricks according to an embodiment of the present invention. Figure 3 This is a schematic diagram of a refractory brick layer with an intermediate layer constructed using a second masonry method, as disclosed in an embodiment of this utility model. From... Figure 2 and Figure 3It can be seen that in this embodiment of the present invention, the gaps between the uppermost and bottommost refractory brick layers 101 constructed using the first masonry method and the middle layer refractory brick layers 101 constructed using the second masonry method are staggered, and the gaps between the refractory bricks in the same refractory brick layer 101 are also staggered. It is worth noting that the masonry method of the refractory brick layers 101 can also be other methods, and this embodiment of the present invention does not limit them.
[0032] Furthermore, as an optional embodiment of this utility model, each of the graphite electrodes 103 includes a graphite electrode body 1030 and a low thermal conductivity refractory brick 1031. One end of the graphite electrode body 1030 is fixedly connected to one end of the low thermal conductivity refractory brick 1031. The other part of the electrode of the graphite electrode body 1030 is not located in the DC submerged arc furnace. Each graphite electrode 103 of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer 101. The other ends of each low thermal conductivity refractory brick are spliced together in a radial arrangement. The low thermal conductivity refractory brick is used to prevent the heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body 1030.
[0033] For example, such as Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of a graphite electrode and the structure between the graphite electrode and the refractory brick layer disclosed in an embodiment of this utility model. The graphite electrode 103 body is made of a high-purity, high-density special graphite material, possessing excellent electrical conductivity and high-temperature resistance. Its low resistivity allows for efficient current conduction, ensuring that during the DC submerged arc furnace smelting process, the current can be stably and with low loss transferred from the external power source to the furnace, generating continuous and stable arc heat. Simultaneously, graphite has good thermal shock resistance, able to withstand frequent temperature changes during smelting, avoiding electrode cracking or damage due to thermal stress. The low thermal conductivity refractory brick can be a novel carbon material with extremely low thermal conductivity, only 1 / 10 to 1 / 20 of that of the graphite electrode 103 body (the specific value depends on the material formulation). This material has a special porous honeycomb microstructure, with numerous closed pores effectively blocking the heat conduction path and effectively isolating the graphite electrode 103 body from the high temperature at the center of the furnace.
[0034] Furthermore, after the bottom layer of refractory bricks 101 at the furnace bottom is completed, the graphite electrodes 103 are installed. Each graphite electrode 103 uses low-thermal-conductivity refractory bricks as a connecting medium, with their other ends spliced together in a radial layout. During installation, a high-precision laser positioning instrument can be used to strictly control the angle and position of each graphite electrode 103, ensuring that the predetermined angle error between adjacent graphite electrodes 103 does not exceed ±0.5°, thereby guaranteeing the uniformity of current distribution. To achieve a tight splicing of the low-thermal-conductivity refractory bricks, the splicing surface of each low-thermal-conductivity refractory brick is machined with high precision to form a mortise and tenon structure with a convex-concave fit. During splicing, a layer of ceramic adhesive, high-temperature sealant, or carbonaceous adhesive is first applied to the surface of the mortise and tenon structure. This ceramic adhesive, high-temperature sealant, or carbonaceous adhesive will cure in a high-temperature environment to form a tough sealing layer, which not only enhances the connection strength at the splice but also further improves the heat insulation effect. After the assembly is completed, a hydraulic fastening device is used to apply uniform pressure to the entire radial graphite electrode group 103, so that the low thermal conductivity refractory bricks are seamlessly bonded together to form a stable overall structure.
[0035] Thus, during the operation of the DC submerged arc furnace, the low thermal conductivity refractory bricks, with their excellent thermal insulation properties, effectively block the high temperature at the furnace center, ensuring that the temperature of the graphite electrode 103 body remains within a reasonable range (typically reducing the temperature rise by 30%-50%). The lower operating temperature significantly slows down the oxidation rate of the graphite electrode 103 body, extending the electrode's service life. According to actual operating data, the electrode replacement cycle can be extended by 1.5-2 times. The radial layout allows the current to diffuse evenly from the center of the furnace bottom outwards, forming a symmetrical and stable electric field distribution within the furnace. This uniform current conduction not only improves the energy conversion efficiency, reducing smelting energy consumption by 10%-15%, but also ensures uniform heating of materials within the furnace, promoting thorough chemical reactions and improving product quality and yield. Simultaneously, the stable electrode structure and current distribution reduce the frequency of electrode arcing and arc breakage faults, lowering equipment maintenance costs and downtime, and improving the continuous operation capability of the DC submerged arc furnace.
[0036] Furthermore, as an optional embodiment of this utility model, the graphite electrode 103 body and the low thermal conductivity refractory brick are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each of the low thermal conductivity refractory bricks are spliced and contacting each other are also bonded and fixed together using a ceramic adhesive. In addition, at the interface between the graphite electrode 103 body and the low thermal conductivity refractory brick, a gradient composite transition layer structure can be adopted to avoid interface cracking caused by differences in the thermal expansion coefficients of the materials, ensuring long-term stability of the connection strength and thermal insulation performance.
[0037] Furthermore, as an optional embodiment of this utility model, the gaps between the refractory bricks in each refractory brick layer 101 are filled with a carbonaceous binder, and the portion of the inner wall of the DC submerged arc furnace body 102 in contact with the refractory bricks and the portion of the outer wall of the graphite electrode 103 in contact with the refractory bricks are also filled with the carbonaceous binder.
[0038] Specifically, the carbonaceous binder is made from high-purity carbon materials, with the addition of special high-temperature resistant inorganic binders and modifying additives. Its main components include graphite powder, carbon black, and pitch coke, possessing a thermal expansion coefficient similar to that of refractory bricks. This allows it to expand and contract synchronously with refractory bricks at high temperatures, preventing cracking due to differences in thermal expansion and contraction. The high-temperature resistant inorganic binders added to the inorganic binder, such as aluminum phosphate and silica sol, undergo chemical reactions at high temperatures to form a high-strength ceramic-like bonding phase, significantly improving bond strength. The modifying additives optimize the rheological properties of the binder, giving it good fluidity at room temperature for easy application and rapid hardening during heating and curing. Furthermore, the carbonaceous binder exhibits excellent chemical stability, resisting the erosion of high-temperature flue gas, molten metal, and corrosive gases generated during the smelting process in a DC submerged arc furnace. Its outstanding impermeability effectively prevents gas and liquid leakage through gaps within the furnace, maintaining a stable smelting atmosphere and reducing damage to the furnace structure.
[0039] Furthermore, when filling the gaps between the refractory bricks in each layer 101, a suitable gap width (usually controlled at 3-5mm) is reserved during the refractory brick laying process. The surfaces of the refractory bricks on both sides of the gap are cleaned using tools such as wire brushes and compressed air to remove dust, oil, and loose particles, ensuring a clean and rough bonding surface to enhance the adhesion of the adhesive. Then, the prepared carbonaceous adhesive is injected into the gap using a dedicated extrusion caulking gun. During the filling process, the caulking gun is moved at a uniform speed to ensure that the adhesive evenly fills the entire gap, avoiding voids or air bubbles. For wider gaps, a layered filling method can be used, allowing the adhesive to partially cure after each layer (approximately 1-2 hours) before applying the next layer to ensure a dense filling. After filling, a scraper is used to smooth the surface of the gap, making it flush with the surface of the refractory bricks to reduce stress concentration at the gap.
[0040] Furthermore, for the portion of the inner wall of the furnace body 102 in contact with the refractory bricks, and the portion of the outer wall of the graphite electrode 103 in contact with the refractory bricks, before installing the refractory bricks, a layer of carbonaceous binder with a thickness of approximately 1-2 mm is uniformly applied to the inner wall of the furnace body 102 and the outer wall of the electrode to form a continuous adhesive layer. Then, the refractory bricks are accurately installed, and a certain pressure is applied to the refractory bricks using a dedicated clamping device (the pressure value is set according to the size of the refractory bricks and the characteristics of the binder, generally 0.5-1 MPa), so that the carbonaceous binder fully fills the tiny gaps between the refractory bricks and the wall surface and expels air. During the filling process, special attention is paid to the corners and irregular areas, which can be supplemented by manual application and compaction to ensure that each contact point is fully bonded. For the contact area between the graphite electrode 103 and the refractory brick, since the graphite electrode 103 will vibrate during operation, after filling the carbonaceous binder, a layer of high-temperature resistant fiber reinforcement material needs to be wrapped around the outside of the contact area to further enhance the stability of the connection and prevent the binder from cracking or falling off due to vibration.
[0041] Furthermore, this embodiment of the invention utilizes a carbonaceous binder for filling, which, in terms of sealing, creates a continuous sealing layer that completely seals gaps, reducing the leakage rate of gas and liquid inside the furnace by over 90%. This effectively maintains the high-temperature, high-pressure smelting environment within the furnace, reducing heat loss and energy consumption. Regarding structural stability, the carbonaceous binder is tightly bonded to the refractory bricks, furnace body 102, and graphite electrode 103, forming a unified structure that enhances the furnace body 102's resistance to thermal and mechanical stress. The high-strength bonding phase generated after the binder cures effectively disperses stress between refractory bricks and between refractory bricks and other components, preventing refractory brick breakage or displacement due to stress concentration and extending the service life of the furnace body 102. In addition, good sealing and a stable structure help reduce pollutant emissions during smelting and improve the working environment. Simultaneously, it reduces the frequency of equipment failures caused by poor sealing and structural instability, decreasing maintenance workload and downtime, and improving the production efficiency of the DC submerged arc furnace.
[0042] This invention addresses the drawback of traditional single-laying methods where aligned gaps easily lead to stress concentration by employing different construction methods for adjacent refractory brick layers and staggered gaps. The staggered gaps between refractory bricks, and between adjacent layers, significantly increase the path length and difficulty for gas and liquid media to penetrate. During smelting, this effectively prevents high-temperature flue gas and molten metal from leaking through gaps in the furnace bottom, reducing the risk of insulation material corrosion and maintaining good furnace insulation performance. Simultaneously, the excellent sealing helps maintain a stable smelting atmosphere inside the furnace, preventing impurities such as air from entering and affecting the smelting reaction, thus ensuring the production of high-quality products. The arrangement of multiple graphite electrodes, with one end concentrated at the center of the furnace bottom and the other end extending out of the furnace body at a predetermined angle, ensures more uniform stress distribution on the electrodes during smelting. This avoids the arcing and arc breaking phenomena caused by uneven stress distribution in traditional layouts, ensuring stable current conduction and improving energy conversion efficiency. Meanwhile, by dividing the furnace bottom space into multiple areas using graphite electrodes, the oscillation amplitude of molten iron at the furnace bottom is reduced, thereby decreasing the scouring effect of the molten iron on the bottom electrodes and extending their lifespan. Therefore, when this embodiment of the invention constructs the furnace bottom of a DC submerged arc furnace using the above-mentioned method, the reliability, safety, and stability of the furnace bottom are improved. Furthermore, the refractory brick layer in this area further reinforces the furnace structure, providing a stable support environment for the graphite electrodes and enhancing the stability of the graphite electrodes within the furnace as well as the overall stability of the furnace system.
[0043] Based on the same inventive concept, this utility model embodiment provides a DC submerged arc furnace, including multiple graphite electrodes and a furnace bottom lining structure as described in the above embodiment of this utility model. Each layer of refractory bricks in the furnace bottom lining structure is laid sequentially from bottom to top along the axial direction of the furnace body. The gaps between adjacent refractory bricks in each refractory brick layer and between refractory bricks in adjacent refractory brick layers are staggered. The bottommost refractory brick layer is laid flat on the furnace bottom of the DC submerged arc furnace, and the multiple graphite electrodes of the DC submerged arc furnace are placed on the bottommost refractory brick layer. On the upper surface of the firebrick layer, one end of each graphite electrode converges at the center of the furnace bottom, and a portion of the other end of each graphite electrode extends out of the furnace body of the DC submerged arc furnace, with adjacent graphite electrodes forming an angle; the remaining refractory brick layers are sequentially built from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrodes. The height of the upper surface of the graphite electrodes is higher than the height of the topmost refractory brick layer, so as to separate the molten liquid near the furnace bottom in the DC submerged arc furnace through the graphite electrodes.
[0044] Furthermore, as an optional embodiment of this utility model, each of the graphite electrodes includes a graphite electrode body and a low thermal conductivity refractory brick. One end of the graphite electrode body is fixedly connected to one end of the low thermal conductivity refractory brick. Part of the electrode at the other end of the graphite electrode body is not located inside the DC submerged arc furnace. Each graphite electrode of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer. The other ends of each low thermal conductivity refractory brick are spliced together in a radial arrangement. The low thermal conductivity refractory brick is used to prevent heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body.
[0045] Furthermore, as an optional embodiment of this utility model, the graphite electrode body and the low thermal conductivity refractory bricks are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each of the low thermal conductivity refractory bricks are spliced and contacted with each other are bonded and fixed together using a ceramic adhesive.
[0046] Furthermore, as an optional embodiment of this utility model, the gaps between the refractory bricks in each layer of refractory bricks are filled with a carbonaceous binder, and the portion of the inner sidewall of the DC submerged arc furnace that contacts the refractory bricks and the portion of the outer sidewall of the graphite electrode that contacts the refractory bricks are also filled with the carbonaceous binder.
[0047] Furthermore, as an optional embodiment of this utility model, the refractory brick layer comprises three layers, with adjacent refractory brick layers constructed in different ways. The bottom and top refractory brick layers are constructed using a first construction method, while the middle refractory brick layers are constructed using a second construction method. The first construction method is a parallel arrangement, in which one graphite electrode is used as a reference electrode, and the long sides of the refractory bricks are arranged sequentially with the reference electrode perpendicular to the long side. The second construction method is a radial arrangement, in which the long sides of the refractory bricks are arranged sequentially with the long sides pointing towards the central axis of the DC submerged arc furnace.
[0048] It should be noted that the DC submerged arc furnace provided in this utility model embodiment and the furnace bottom masonry structure of the DC submerged arc furnace provided in this utility model embodiment are based on the same application concept. Therefore, the specific implementation of this embodiment can refer to the implementation of the aforementioned furnace bottom masonry structure of the DC submerged arc furnace, and has the same or similar beneficial effects. Repeated parts will not be described again.
[0049] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0050] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.
Claims
1. A furnace bottom lining structure for a DC submerged arc furnace, characterized in that, The furnace bottom masonry structure includes: multiple layers of refractory bricks, with each layer of refractory bricks being laid sequentially from bottom to top along the axial direction of the furnace body of the DC submerged arc furnace; The gaps between adjacent refractory bricks in each refractory brick layer and between refractory bricks in adjacent refractory brick layers are all staggered. The bottom layer of refractory bricks is laid flat on the bottom of the DC submerged arc furnace, and multiple graphite electrodes of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks. One end of each graphite electrode converges at the center of the bottom of the furnace, and part of the other end of each graphite electrode extends out of the furnace body of the DC submerged arc furnace, and an angle is formed between adjacent graphite electrodes. The remaining refractory brick layers are laid sequentially from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrode. The height of the upper surface of the graphite electrode is higher than the height of the topmost refractory brick layer, so as to separate the molten liquid near the bottom of the DC submerged arc furnace through the graphite electrode.
2. The furnace bottom lining structure of the DC submerged arc furnace according to claim 1, characterized in that, Each of the graphite electrodes includes a graphite electrode body and a low thermal conductivity refractory brick. One end of the graphite electrode body is fixedly connected to one end of the low thermal conductivity refractory brick. The other end of the graphite electrode body is not located inside the DC submerged arc furnace. Each graphite electrode of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer. The other ends of each low thermal conductivity refractory brick are spliced together in a radial arrangement. The low thermal conductivity refractory brick is used to prevent heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body.
3. The furnace bottom lining structure of the DC submerged arc furnace according to claim 2, characterized in that, The graphite electrode body and the low thermal conductivity refractory bricks are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each low thermal conductivity refractory brick are spliced and contacted with each other are also bonded and fixed together using a ceramic adhesive.
4. The furnace bottom lining structure of the DC submerged arc furnace according to claim 1, characterized in that, The gaps between the refractory bricks in each layer of refractory bricks are filled with carbonaceous binder. The part of the inner side wall of the DC submerged arc furnace that contacts the refractory bricks and the part of the outer side wall of the graphite electrode that contacts the refractory bricks are also filled with carbonaceous binder.
5. The furnace bottom lining structure of the DC submerged arc furnace according to claim 1, characterized in that, The refractory brick layer consists of three layers, with adjacent refractory brick layers being constructed in different ways. The bottom and top refractory brick layers are constructed using the first method, while the middle refractory brick layers are constructed using the second method. The first construction method is a parallel arrangement, in which one of the graphite electrodes is used as a reference electrode and the refractory bricks are arranged sequentially with their long sides perpendicular to the reference electrode. The second construction method is a radial arrangement, in which the long sides of the refractory bricks are arranged sequentially with their long sides pointing towards the central axis of the DC submerged arc furnace.
6. A DC submerged arc furnace, characterized in that: It includes multiple graphite electrodes and a furnace bottom lining structure of a DC submerged arc furnace as described in any one of claims 1-5, wherein each layer of refractory bricks in the furnace bottom lining structure is laid sequentially from bottom to top along the axial direction of the furnace body of the DC submerged arc furnace. The gaps between adjacent refractory bricks in each refractory brick layer and between refractory bricks in adjacent refractory brick layers are all staggered. The bottom layer of refractory bricks is laid flat on the bottom of the DC submerged arc furnace, and multiple graphite electrodes of the DC submerged arc furnace are placed on the upper surface of the bottom layer of refractory bricks. One end of each graphite electrode converges at the center of the bottom of the furnace, and part of the other end of each graphite electrode extends out of the furnace body of the DC submerged arc furnace, and an angle is formed between adjacent graphite electrodes. The remaining refractory brick layers are laid sequentially from bottom to top along the axial direction of the DC submerged arc furnace and are located in the area enclosed by the inner wall of the furnace body and the outer wall of the graphite electrode. The height of the upper surface of the graphite electrode is higher than the height of the topmost refractory brick layer, so as to separate the molten liquid near the bottom of the DC submerged arc furnace through the graphite electrode.
7. The DC-DC submerged arc furnace according to claim 6, characterized in that, Each of the graphite electrodes includes a graphite electrode body and a low thermal conductivity refractory brick. One end of the graphite electrode body is fixedly connected to one end of the low thermal conductivity refractory brick. The other end of the graphite electrode body is not located inside the DC submerged arc furnace. Each graphite electrode of the DC submerged arc furnace is placed on the upper surface of the bottommost refractory brick layer. The other ends of each low thermal conductivity refractory brick are spliced together in a radial arrangement. The low thermal conductivity refractory brick is used to prevent heat from the center of the DC submerged arc furnace from being transferred to the graphite electrode body.
8. The DC-DC submerged arc furnace according to claim 6, characterized in that, The graphite electrode body and the low thermal conductivity refractory bricks are bonded and fixed together using a ceramic adhesive, and the areas where the other ends of each low thermal conductivity refractory brick are spliced and contacted with each other are also bonded and fixed together using a ceramic adhesive.
9. The DC submerged arc furnace according to claim 6, characterized in that, The gaps between the refractory bricks in each layer of refractory bricks are filled with carbonaceous binder. The part of the inner side wall of the DC submerged arc furnace that contacts the refractory bricks and the part of the outer side wall of the graphite electrode that contacts the refractory bricks are also filled with carbonaceous binder.
10. The DC submerged arc furnace according to claim 6, characterized in that, The refractory brick layer consists of three layers, with adjacent refractory brick layers being constructed in different ways. The bottom and top refractory brick layers are constructed using the first method, while the middle refractory brick layers are constructed using the second method. The first construction method is a parallel arrangement, in which one of the graphite electrodes is used as a reference electrode and the refractory bricks are arranged sequentially with their long sides perpendicular to the reference electrode. The second construction method is a radial arrangement, in which the long sides of the refractory bricks are arranged sequentially with their long sides pointing towards the central axis of the DC submerged arc furnace.