A method for lining a furnace wall of an electric arc furnace and for hanging slag

Abstract

This application provides a method for constructing a slag-coating wall in a submerged arc furnace. The furnace wall comprises: a furnace shell with an internal accommodating space; a water-cooled wall located on the inner wall of the accommodating space within the furnace shell; a slag-coating layer located on the side of the water-cooled wall away from the furnace shell; and a semi-solid protective layer located on the side of the slag-coating layer away from the water-cooled wall. Both the slag-coating layer and the semi-solid protective layer are formed by the cooling of molten material within the furnace upon contact with the water-cooled wall. The molten material includes molten slag and molten metal, and the slag-coating layer is directly attached to the surface of the water-cooled wall. This application, through the above structure, enables the molten material to spontaneously form a continuous slag-coating layer and a semi-solid protective layer radially on the surface of the water-cooled wall, thereby effectively isolating the high-temperature molten material from direct erosion of the metal structure and significantly improving the furnace wall's erosion resistance.

Description

Technical Field

[0001] This application relates to the field of metallurgical engineering technology, and in particular to a method for slag coating on the furnace wall of an electric arc furnace. Background Technology

[0002] In the smelting process of nickel-iron in electric submerged arc furnaces (EAFs) using laterite nickel ore and other raw materials, the furnace is subjected to complex conditions of high temperature, strong reducing atmosphere, and coexistence of molten metal and slag for extended periods. The furnace lining material must not only withstand heat loads exceeding 1000 degrees Celsius but also resist the continuous chemical erosion from molten metal and highly acidic slag, as well as the physical scouring effect of material flow. However, current EAF linings are prone to rapid erosion under the long-term erosion and scouring effects of high-temperature molten metal and slag, and their insufficient fit with the copper water-cooled walls leads to unstable heat transfer, affecting the furnace's operational safety and efficiency.

[0003] In view of this, how to design the furnace wall of an electric arc furnace to ensure high-temperature corrosion resistance while improving thermal stress resistance and thermal conductivity regulation, so as to effectively extend the service life of the furnace lining, reduce the frequency of furnace shutdown maintenance, and reduce the overall operating cost, has become an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the purpose of this application is to propose a method for the furnace wall and slag coating of an electric arc furnace to solve or partially solve the above-mentioned problems.

[0005] To achieve the above objectives, this application provides a furnace wall for a submerged arc furnace, comprising:

[0006] A furnace shell, the interior of which is provided with a receiving space; A water-cooled wall is located on the inner wall of the space within the furnace shell; The slag layer is located on the side of the water-cooled wall away from the furnace shell; A semi-solid protective layer is located on the side of the slag-coated layer away from the water-cooled wall; The slag layer and the semi-solid protective layer are both formed by the cooling of molten material in the furnace after contacting the water-cooled wall. The molten material includes molten slag and molten metal, and the slag layer is directly attached to the surface of the water-cooled wall.

[0007] Optionally, the surface of the water-cooled wall away from the furnace shell is provided with a plurality of slag-hanging grooves recessed into the water-cooled wall, and the depth of the recessed slag-hanging grooves is less than the thickness of the water-cooled wall; and / or, The surface of the water-cooled wall away from the furnace shell is provided with a plurality of slag-hanging grooves that are recessed into the interior of the water-cooled wall. The depth of the slag-hanging grooves is related to the thermal conductivity of the slag; the higher the thermal conductivity, the deeper the slag-hanging grooves, and vice versa.

[0008] Optionally, the cross-sectional shape of the slag-hanging trough includes any one or more combinations of rectangle, square, triangle, or trapezoid, and the plurality of slag-hanging troughs are either intersecting or spaced apart along the same direction; or, The slag-hanging trough has a dovetail groove structure.

[0009] Optionally, along the depth direction of the furnace shell, the slag layer includes a solid slag layer segment and a solid metal layer segment; the solid slag layer segment is formed by the solidification and adhesion of molten slag in the furnace after contacting the water-cooled wall and under cooling action, and the solid metal layer segment is formed by the solidification of molten metal in the furnace after contacting the water-cooled wall and under cooling action. The solid metal layer is located in a region near the bottom of the furnace shell.

[0010] Optionally, along the depth direction of the furnace shell, the semi-solid protective layer includes a semi-solid slag layer and a semi-solid metal layer; the semi-solid slag layer is formed by the molten slag in the furnace contacting the solid slag layer and then cooling, and the semi-solid metal layer is formed by the molten metal in the furnace contacting the solid metal layer and then cooling. In this configuration, along the radial direction of the furnace shell, the semi-solid metal layer is arranged adjacent to the solid metal layer, and the semi-solid slag layer is arranged adjacent to the solid slag layer.

[0011] Optionally, along the radial direction of the furnace shell, the solid metal layer segment includes a first metal protective layer and a second metal protective layer; the first metal protective layer is directly attached to the surface of the water-cooled wall.

[0012] Optionally, along the radial direction of the furnace shell, the hardness of the first metal protective layer, the second metal protective layer, and the semi-solid metal layer decreases sequentially; and / or, Along the radial direction of the furnace shell, the hardness of the solid slag layer and the semi-solid slag layer decreases sequentially.

[0013] Optionally, the water-cooled wall is divided into at least two independent cooling zones along the depth direction of the furnace shell, each cooling zone having a different cooling intensity, and the cooling intensity of the cooling zone located near the bottom of the furnace shell is greater than that of the other cooling zones.

[0014] Optionally, the structural parameters of the plurality of slag hanging troughs increase in a gradient along the depth direction of the furnace shell, and the structural parameters include at least one of the following: trough depth, trough width, or cross-sectional angle.

[0015] Based on the same inventive concept, this application also provides a slag-coating method for preparing the furnace wall of a submerged arc furnace as described above, the method comprising: A submerged arc furnace body is provided, and a cooling medium is introduced into the interior of the water-cooled wall to keep the water-cooled wall at a low temperature. During the heating stage, the material inside the furnace is heated so that it gradually melts to form molten slag. When the molten slag comes into contact with the surface of the water-cooled wall, it cools down and adheres under the cooling effect of the water-cooled wall, forming a slag layer and a semi-solid protective layer on the surface of the water-cooled wall in the radial direction of the furnace shell. During the smelting stage of the electric arc furnace, the molten slag undergoes a reduction reaction to generate molten metal. Under the action of gravity, the molten metal settles towards the bottom of the furnace and gradually rises to the liquid level. The molten metal first contacts the solid slag layer in the slag layer and locally melts or replaces the solid slag layer. When the molten metal further contacts the water-cooled wall, it solidifies under the action of cooling, and a first metal protective layer, a second metal protective layer, and a semi-solid metal layer are formed sequentially along the radial direction of the furnace shell at the contact interface. Wherein, the hardness of the first metal protective layer is greater than the hardness of the second metal protective layer, and the hardness of the second metal protective layer is greater than the hardness of the semi-solid metal layer segment.

[0016] As can be seen from the above, the submerged arc furnace wall and slag-coating method provided in this application include: a furnace shell with an internal accommodating space; a water-cooled wall located on the inner wall of the accommodating space; a slag-coating layer located on the side of the water-cooled wall away from the furnace shell; and a semi-solid protective layer located on the side of the slag-coating layer away from the water-cooled wall. Both the slag-coating layer and the semi-solid protective layer are formed by the cooling of molten material inside the furnace after contacting the water-cooled wall. The molten material includes molten slag and molten metal, and the slag-coating layer is directly attached to the surface of the water-cooled wall. This application, through the aforementioned structure, enables the molten material to spontaneously form a continuous slag layer and a semi-solid protective layer in the radial direction on the surface of the water-cooled wall, serving as the actual smelting working layer. This effectively isolates the direct erosion of the metal structure by the high-temperature molten material, significantly improving the furnace wall's erosion resistance. Simultaneously, the seamless adhesion between the slag layer and the water-cooled wall reduces interfacial thermal resistance and improves thermal conductivity stability. Furthermore, the semi-solid protective layer can absorb thermal stress and buffer material erosion through its solid-liquid coexistence characteristics, helping to improve thermal shock resistance and reduce the risk of structural damage. In addition, relying on the in-situ generation and dynamic replenishment mechanism of the protective layer, self-repair of local damage can be achieved, thereby extending the overall service life of the furnace wall and reducing reliance on refractory material replacement, thus lowering maintenance costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a side view structural diagram of the electric arc furnace according to an embodiment of this application; Figure 2 This is a front view structural diagram of the electric arc furnace according to an embodiment of this application; Figure 3 for Figure 1 A magnified schematic diagram of a portion of the furnace wall structure in section A of the electric arc furnace; Figure 4 for Figure 3 A magnified schematic diagram of a portion of the structure of the submerged arc furnace wall in section B; Figure 5 This is a top view of the water-cooled wall structure according to an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures: 100. Furnace shell; 110. Storage space; 200, Water-cooled wall; 210, Slag trap; 220, Inlet; 230, Outlet; 300. Slag layer; 310. Solid slag layer section; 320. Solid metal layer section; 321. First metal protective layer; 322. Second metal protective layer; 400. Semi-solid protective layer; 410. Semi-solid slag layer; 420. Semi-solid metal layer; 500A, molten slag; 500B, molten metal; 600. Feed port. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] As described in the background section, in the smelting process of nickel-iron in a submerged arc furnace using laterite nickel ore as raw material, the furnace is subjected to a complex environment characterized by high temperature (typically above 1400℃), a strong reducing atmosphere, and the coexistence of molten metal and highly acidic slag. Under these conditions, the molten material inside the furnace exhibits strong chemical activity and fluidity. On the one hand, components such as SiO2 and Al2O3 in the molten slag exert a continuous chemical erosion effect on the traditional furnace lining material; on the other hand, the molten metal and slag continuously scour the traditional furnace lining during their flow, thus forming a coupled mechanism of chemical erosion and physical scouring. Simultaneously, due to the significant temperature gradient within the furnace, the furnace wall structure must repeatedly withstand the thermal stress impact caused by thermal expansion and contraction. Under the combined effects of these multiple factors, the traditional furnace lining material is highly susceptible to erosion, spalling, structural relaxation, and thermal cracking, thereby affecting the long-term stable operation of the submerged arc furnace.

[0023] To address the aforementioned issues, relevant technologies employ refractory materials primarily composed of magnesia bricks, magnesia-carbon bricks, or magnesia-chrome-carbon bricks, which are used to form the furnace lining structure through a masonry process. These materials, relying on their high melting point and resistance to slag erosion, can delay lining wear to some extent. Their mechanism of action lies in the material itself directly bearing the high temperatures and erosion, achieving passive erosion resistance. However, due to the constant chemical reaction interface between the molten slag and the refractory material, and the unavoidable presence of pores and microcracks within the material, corrosive media gradually penetrate the material under prolonged high-temperature conditions, leading to a decrease in structural strength and eventual spalling failure. Furthermore, the joint areas between refractory bricks are more prone to becoming weak points for erosion, thus accelerating the overall failure process of the furnace lining.

[0024] To further reduce furnace lining temperature and slow down the erosion rate, some submerged arc furnaces (or electric submerged arc furnaces) have introduced copper water-cooled wall structures. This involves placing copper cooling components between the furnace shell and the refractory material, and circulating water to enhance heat exchange, thereby lowering the furnace lining temperature and forming a cooling layer on the hot surface of the lining. Essentially, this suppresses the erosion reaction rate by enhancing thermal conductivity and lowering temperature. However, this technology still relies on the refractory material as the direct working layer, and its cooling effect is highly dependent on the contact state between the refractory material and the copper water-cooled wall. If there is an assembly gap between the two, an air layer or a low thermal conductivity layer will form at the interface, significantly increasing thermal resistance. This prevents heat from being effectively conducted to the water-cooled wall, leading to localized temperature increases and inducing overheating failure of the refractory material. Furthermore, because the refractory material itself has poor thermal conductivity, it is difficult to achieve rapid and uniform heat dissipation, easily forming localized heat concentration areas, further exacerbating thermal stress damage.

[0025] It should also be noted that in related technologies, the copper water-cooled wall and refractory material are usually simply bonded or mechanically fixed, lacking an effective transition structure or functional layer design. This makes it difficult to achieve synergistic optimization in terms of erosion resistance, thermal shock resistance, and thermal conductivity control. More specifically, on the one hand, the refractory material undertakes the main erosion resistance function, but its lifespan is limited; on the other hand, although the water-cooled wall has good thermal conductivity, it cannot directly participate in the erosion resistance process. The overall structure is still a passive protection system dominated by the refractory material, which cannot fundamentally solve the problem of easy wear and tear of the furnace lining.

[0026] Based on the above analysis, it can be seen that the current furnace wall structure still relies on refractory materials to directly withstand high-temperature erosion, and the water-cooled wall only exists as an auxiliary cooling means and has failed to effectively participate in the anti-erosion process. At the same time, the problem of unstable interfacial heat transfer further weakens the cooling effect, thus limiting the improvement of furnace lining life.

[0027] In view of this, this application proposes a submerged arc furnace wall that does not rely on refractory brick masonry structure. By directly adopting a water-cooled wall as the main structure and utilizing the in-situ cooling of molten material inside the furnace to form a slag layer and a semi-solid protective layer, the furnace wall achieves self-sustaining protection by transforming from relying on the consumption of refractory materials for protection to forming a protective layer through the molten material inside the furnace. This effectively extends the service life of the furnace lining, reduces maintenance costs, and improves the safety and operating efficiency of the submerged arc furnace.

[0028] The following is in conjunction with the appendix Figure 1-5 The embodiments of this application will be described in detail below.

[0029] In some embodiments, such as Figure 1 , Figure 2 and Figure 3 As shown, a furnace wall for a submerged arc furnace is provided, comprising: Furnace shell 100, wherein the furnace shell 100 is provided with an accommodating space 110; Water-cooled wall 200 is located on the inner wall of the accommodating space 110 in the furnace shell 100; The slag layer 300 is located on the side of the water-cooled wall 200 away from the furnace shell 100; A semi-solid protective layer 400 is located on the side of the slag-coated layer 300 away from the water-cooled wall 200; The slag layer 300 and the semi-solid protective layer 400 are both formed by the cooling of molten material in the furnace after contacting the water-cooled wall 200. The molten material includes molten slag 500A and molten metal 500B, and the slag layer 300 is directly attached to the surface of the water-cooled wall 200.

[0030] It should be noted that this embodiment addresses the problems of high-temperature erosion, thermal shock, and structural lifespan of submerged arc furnace walls by proposing a composite furnace wall structure with layers arranged from the inside out. Overall, the furnace wall sequentially includes a furnace shell 100, a water-cooled wall 200, a slag-coated layer 300, and a semi-solid protective layer 400, with each layer continuously arranged along its thickness. The furnace shell 100 serves as the outermost load-bearing unit, providing overall rigidity and a sealing foundation. The water-cooled wall 200 serves as the core functional layer, providing continuous cooling conditions. The inner slag-coated layer 300 and the semi-solid protective layer 400 are the actual smelting working layers generated in situ by the molten material inside the furnace under a controlled temperature field, together forming a protective structure for high-temperature environments.

[0031] Specifically, the furnace shell 100 can be made of high-strength steel, which mainly bears the external load and provides structural support, and forms a stable overall frame through reliable connection with the water-cooled wall 200 (such as welding or bolting). On this basis, the water-cooled wall 200 is located inside the furnace shell 100 and can be made of a high thermal conductivity metal material (such as copper or copper alloy). Cooling water channels are arranged inside it, and heat is continuously removed through the circulation of cooling medium (such as cooling water), thereby establishing a stable low-temperature interface on its inner surface.

[0032] Based on the above structure, a significant temperature gradient can be formed along the thickness direction of the furnace wall (or the radial direction along the furnace shell 100), providing the necessary conditions for the formation of the subsequent protective layer. Specifically, driven by this temperature gradient, the molten slag 500A near the water-cooled wall 200 can be rapidly cooled and solidified, forming a dense slag layer 300 in situ, which serves as the actual smelting working layer. Optionally, the slag layer 300 is tightly attached to the water-cooled wall 200 through metallurgical bonding or mechanical interlocking. This scheme forms the slag layer 300 through direct cooling, which not only effectively isolates the subsequent molten material from direct erosion of the metal wall, but also significantly reduces contact thermal resistance and ensures stable heat conduction because there are no interface gaps caused by traditional refractory material laying. At the same time, the temperature in the area inside the slag layer 300 (or the side away from the water-cooled wall 200) is relatively high, and the molten material is not completely solidified, forming a semi-solid protective layer 400 with certain fluidity and plasticity. This layer can also be used as the actual smelting working layer, and there is a continuous transition between it and the slag layer 300.

[0033] Furthermore, the semi-solid protective layer 400 plays a buffering and regulating role during operation. On the one hand, its solid-liquid coexistence characteristics enable it to absorb thermal stress through plastic deformation, reducing structural damage caused by sudden temperature changes; on the other hand, its flow characteristics can effectively weaken the impact energy brought by the scouring of materials in the furnace, and achieve dynamic self-repair by replenishing with new molten material when local damage occurs. Thus, the slag layer 300 and the semi-solid protective layer 400 respectively undertake the functions of rigid protection and flexible buffering, and form a stable synergy under the temperature control of the water-cooled wall 200.

[0034] Based on the aforementioned structure and mechanism, this embodiment transforms the furnace wall's protection from relying on the consumption of refractory materials to achieving self-sustaining protection through a protective layer formed by molten material within the furnace. By constructing a continuous heat conduction path and multi-layered functional division, it not only effectively improves the furnace wall's resistance to erosion and thermal shock but also significantly enhances its overall thermal conductivity stability and structural reliability. Simultaneously, relying on the dynamic generation and self-healing characteristics of the protective layer, it reduces reliance on consumable refractory materials, thereby extending service life and lowering maintenance costs.

[0035] Furthermore, it should be noted that, unlike related technologies that commonly use refractory materials such as magnesia bricks, magnesia-carbon bricks, or magnesia-chrome-carbon bricks to form the furnace lining structure through masonry, this technical solution eliminates the traditional refractory material lining. Instead, it utilizes a water-cooled wall 200 to construct a controlled temperature field, allowing the molten material inside the furnace to cool in situ on its surface and spontaneously form a slag layer 300 and a semi-solid protective layer 400, thereby constructing a protective structure. This technical solution is not a simple replacement of refractory materials, but rather a shift in thinking from "relying on externally added refractory materials for erosion resistance" to "using operating conditions to induce the self-generation of the protective layer."

[0036] Specifically, in related technologies, refractory materials not only serve as insulation but also constitute a necessary structural element of the furnace lining, exhibiting industry consensus and path dependence. This solution, however, utilizes a reverse approach, employing an enhanced cooling mechanism to stably adhere high-temperature molten materials to the surface of the water-cooled wall 200, forming a continuous protective layer (in other words, the furnace lining of this application is primarily composed of the water-cooled wall 200, while also including in-situ cooling on its surface to spontaneously form a slag layer 300 and a semi-solid protective layer 400). To achieve this process, coordinated control of heat transfer conditions, temperature gradients, and material phase change behavior is required. This includes: selecting high thermal conductivity materials and establishing cooling water channels within the water-cooled wall 200 to improve heat exchange capacity and create a stable low-temperature boundary on the wall surface; regulating the cooling water flow rate and flow state (e.g., adjusting the cooling water supply flow rate or velocity to change the overall heat transfer intensity of the water-cooled wall 200, maintaining its surface temperature within a preset range; or, through a zoned water supply method, setting independent cooling circuits for water-cooled walls 200 at different heights or in different areas, and adjusting the flow rate or pressure of each circuit to achieve the desired effect in the furnace lining). Differential temperature distribution is formed at different locations on the wall, creating a continuous temperature gradient from low to high in the radial direction of the furnace wall. This induces the molten material to solidify rapidly in the area near the water-cooled wall 200, forming a dense slag layer 300, while maintaining a partially molten state in the area away from the water-cooled wall 200 to form a semi-solid protective layer 400. At the same time, by controlling the stability of temperature conduction (for example, by setting continuous and uniformly distributed cooling water channels inside the water-cooled wall 200 and ensuring uniform flow distribution between the channels), local overcooling or overheating is avoided, which could cause the protective layer to fall off or fail to form. This achieves the stable coexistence and continuous transition of the solid and semi-solid layers.

[0037] This embodiment provides a submerged arc furnace wall, comprising: a furnace shell 100, the furnace shell 100 having an internal accommodating space 110; a water-cooled wall 200 located on the inner wall of the accommodating space 110 within the furnace shell 100; a slag-coated layer 300 located on the side of the water-cooled wall 200 away from the furnace shell 100; and a semi-solid protective layer 400 located on the side of the slag-coated layer 300 away from the water-cooled wall 200. Both the slag-coated layer 300 and the semi-solid protective layer 400 are formed by the cooling of molten material within the furnace after contacting the water-cooled wall 200. The molten material includes molten slag 500A and molten metal 500B, and the slag-coated layer 300 is directly attached to the surface of the water-cooled wall 200. In this embodiment, the above-described structure enables the molten material to spontaneously form a continuous slag layer 300 and a semi-solid protective layer 400 in a radial direction on the surface of the water-cooled wall 200, serving as a substantial smelting working layer. This effectively isolates the metal structure from direct erosion by the high-temperature molten material, significantly improving the furnace wall's erosion resistance. Simultaneously, the slag layer 300 adheres seamlessly to the water-cooled wall 200, reducing interfacial thermal resistance and improving thermal conductivity stability. Furthermore, the semi-solid protective layer 400 can absorb thermal stress and buffer material erosion through its solid-liquid coexistence characteristics, helping to improve thermal shock resistance and reduce the risk of structural damage. In addition, relying on the in-situ generation and dynamic replenishment mechanism of the protective layer, self-repair of local damage can be achieved, thereby extending the overall service life of the furnace wall and reducing reliance on refractory material replacement, thus lowering maintenance costs.

[0038] In some embodiments, such as Figure 1 , Figure 3 and Figure 5 As shown, the surface of the water-cooled wall 200 away from the furnace shell 100 is provided with a plurality of slag-hanging grooves 210 recessed into the water-cooled wall 200, and the depth of the recessed slag-hanging grooves 210 is less than the thickness of the water-cooled wall 200; and / or, The surface of the water-cooled wall 200 away from the furnace shell 100 is provided with a plurality of slag-hanging grooves 210 that are recessed into the interior of the water-cooled wall 200. The depth of the slag-hanging grooves 210 is related to the thermal conductivity of the slag. The higher the thermal conductivity, the deeper the slag-hanging grooves, and vice versa.

[0039] Specifically, since the surface of the water-cooled wall 200 is a relatively smooth metal interface, the molten material is easily affected by flow scouring or thermal stress when it initially adheres to its surface, causing it to slip or fall off. Therefore, by pre-setting a recessed structure on the surface, a containment space 110 can be formed in the microscopic and local areas, providing a stable attachment starting point for the initially solidified slag, thereby improving the nucleation and retention capacity of the slag layer 300.

[0040] Building upon this, the recessed structure of the slag-coating groove 210 further enhances the mechanical interlocking between the slag-coating layer 300 and the water-cooled wall 200. When the molten material enters the slag-coating groove 210 and cools and solidifies, it forms an embedded solid structure within the groove, allowing the slag-coating layer 300 to achieve a stable bond not only through interface adhesion but also through geometric constraints. Compared to planar adhesion, this composite connection method combining embedding and adhesion significantly improves the stability of the slag-coating layer 300 under high-temperature erosion and thermal cycling conditions, thereby reducing the risk of large-area peeling.

[0041] Furthermore, limiting the depth of the slag-coating tank 210 to less than the thickness of the water-cooled wall 200 can, on the one hand, prevent the tank from penetrating or excessively weakening the effective cross-section of the water-cooled wall 200, thus ensuring its overall mechanical strength and pressure-bearing capacity; on the other hand, an appropriate tank depth can maintain the good thermal conductivity of the water-cooled wall 200 without significantly increasing the heat transfer path, thereby ensuring that it can still form sufficient cooling capacity in the tank bottom and tank wall areas, promoting the continuous and stable formation of the slag-coating layer 300.

[0042] Furthermore, the depth of the slag-coating groove 210 is set to be related to the thermal conductivity of the slag (i.e., the ability of the slag to conduct heat). The higher the thermal conductivity, the deeper the slag-coating groove 210, and vice versa. Specifically, the higher the thermal conductivity of the slag, the stronger its heat transfer capacity. To ensure that the molten slag 500A can form an effective temperature gradient and achieve stable solidification in the groove, the depth of the slag-coating groove 210 can be appropriately increased to enhance the local cooling effect and the embedding effect. Conversely, when the thermal conductivity of the slag is low, to avoid reducing the cooling efficiency due to an excessively long heat transfer path, the groove depth can be appropriately reduced to ensure that the area in the groove still has sufficient cooling capacity. By matching the groove depth with the thermal conductivity of the slag, the stable generation and adhesion of the slag layer 300 can be achieved while ensuring heat transfer efficiency.

[0043] It should also be noted that during the operation of the electric arc furnace, due to differences in furnace temperature, material composition, and melting state, the thermal conductivity of the slag varies significantly at different heights. The lower slag near the furnace bottom has the highest thermal conductivity due to the sedimentation of molten metal, higher density, and higher crystal content. The middle slag is mainly in a molten liquid state; although some crystals are present, its high fluidity results in a moderate thermal conductivity. The upper slag at the furnace top, where newly added material has not yet fully melted, has high fluidity, high viscosity, and may contain air bubbles, resulting in the lowest thermal conductivity. Overall, the thermal conductivity of the slag gradually decreases from bottom to top along the furnace height.

[0044] Furthermore, the distribution of multiple slag-coating grooves 210 can form discrete anchoring units on the surface of the water-cooled wall 200. Even if the slag layer 300 falls off in a local area, its adjacent areas can still maintain stable adhesion and act as new attachment cores to promote the re-solidification of molten material, achieving rapid reconstruction of the protective layer. This structure can form a zoned, stable, and locally recoverable protective structural layer, which is beneficial to improving the overall operational reliability.

[0045] This embodiment improves the initial adhesion and long-term stability of the slag layer 300 by setting multiple recessed slag-hanging grooves 210 on the surface of the water-cooled wall 200 and controlling the groove depth to be less than the thickness of the water-cooled wall 200. This achieves a composite fixation combining embedding and adhesion. Furthermore, the groove depth is designed to match the thermal conductivity of the slag, further enhancing the initial adhesion and long-term stability of the slag layer 300 and achieving a composite fixation combining embedding and adhesion. In addition, while ensuring the structural strength and thermal conductivity of the water-cooled wall 200, the erosion resistance and peeling resistance of the protective layer are enhanced, thereby further improving the overall erosion resistance, operational stability, and service life of the furnace wall.

[0046] In some embodiments, such as Figure 1 , Figure 3 and Figure 5 As shown, the cross-sectional shape of the slag hanging trough 210 includes any one or more combinations of rectangle, square, triangle or trapezoid, and the plurality of slag hanging troughs 210 are distributed in an intersecting manner or at intervals along the same direction.

[0047] Specifically, the slag-coating trough 210 is designed with various cross-sectional shapes, such as rectangles, squares, triangles, or trapezoids, or combinations thereof, to optimize the adhesion and stress distribution between the slag-coating layer 300 and the water-cooled wall 200. Different shaped troughs can form different mechanical interlocking structures when the molten material cools and solidifies, allowing the slag-coating layer 300 to be more stably fixed to the surface of the water-cooled wall 200, reducing localized peeling caused by the scouring of the molten metal 500B and slag flow.

[0048] It should be noted that the trough design can be selected according to the actual smelting conditions to balance slag load, cooling efficiency and structural stability.

[0049] Furthermore, the multiple slag-coating grooves 210 can be arranged in a cross-shaped or spaced-apart manner along the same direction, thereby evenly distributing the stress on the slag layer 300 and avoiding localized stress concentration that could lead to cracking or detachment of the slag layer 300. Specifically, a cross-shaped layout can form an interlaced mechanical structure with shear and tensile strength in different directions, while a spaced-apart layout in the same direction facilitates the uniform distribution of heat and stress along a specific direction. Through a reasonable spatial distribution design, the heat conduction path can be optimized while ensuring slag adhesion, thereby improving the overall cooling efficiency of the water-cooled wall 200.

[0050] For example, in some embodiments, the slag-hanging groove 210 is a dovetail groove structure.

[0051] Specifically, designing the slag-hanging groove 210 as a dovetail groove structure further enhances the mechanical bonding between the slag-hanging layer 300 and the water-cooled wall 200. The dovetail groove, with its gradually tapering geometry (e.g., trapezoidal, with the longer side of the trapezoid facing the slag-hanging layer 300), allows the solidified slag to form a self-locking structure within the groove, preventing it from easily detaching from the surface of the water-cooled wall 200 even under the influence of high-temperature molten material scouring and thermal expansion. This structure is particularly suitable for high-temperature, high-scouring smelting environments, significantly improving the durability and stability of the slag-hanging layer 300.

[0052] This embodiment, through the design of diverse and rationally distributed trough shapes and dovetail structures, can effectively improve the adhesion and structural stability of the slag layer 300, while optimizing the distribution of thermal stress and the heat conduction path, thereby extending the service life of the furnace wall and reducing the frequency of maintenance.

[0053] In some embodiments, such as Figure 1 and Figure 3 As shown, along the depth direction of the furnace shell 100, the slag layer 300 includes a solid slag layer section 310 and a solid metal layer section 320; the solid slag layer section 310 is formed by the solidification and adhesion of molten slag 500A in the furnace after contacting the water-cooled wall 200 under cooling action; the solid metal layer section 320 is formed by the solidification of molten metal 500B in the furnace after contacting the water-cooled wall 200 under cooling action. The solid metal layer 320 is disposed on one side near the bottom of the furnace shell 100.

[0054] Specifically, due to the significant differences in physicochemical properties between molten slag 500A and molten metal 500B, molten slag 500A has higher viscosity and stronger chemical corrosiveness, while molten metal 500B has higher density and stronger fluidity. Due to gravity and the difference in physical properties, molten slag 500A naturally floats above molten metal 500B in the furnace, while molten metal 500B is deposited near the bottom of the furnace, thus forming a distribution pattern of molten slag 500A on top and molten metal 500B on the bottom in the 100mm depth direction of the furnace shell.

[0055] Utilizing this natural distribution pattern, the slag layer 300 achieves in-situ solidification through surface cooling of the water-cooled wall 200: the upper molten slag 500A rapidly solidifies upon contact with the water-cooled wall 200, forming a solid slag layer segment 310. This dense slag layer effectively isolates the molten slag 500A from chemical erosion of the water-cooled wall 200, preventing damage to the metal structure from the high-acidity slag liquid. The lower molten metal 500B first contacts the solid slag layer segment 310, locally melting or replacing it. When the molten metal 500B further contacts the water-cooled wall 200, it solidifies under cooling to form a solid metal layer segment 320 located at the bottom of the furnace shell 100. This solid metal layer segment 320 also enhances its resistance to metal flow erosion and localized high temperatures through a self-locking structure, making the bottom area more stable.

[0056] Furthermore, the solid slag layer 310 and the solid metal layer 320 work together to form a longitudinally gradient composite protective structure. The upper slag layer protects against the chemical erosion of the water-cooled wall 200 by the molten slag 500A, while the lower metal layer protects against the scouring of the molten iron. Simultaneously, the two layers naturally bond together during the cooling and solidification process, forming a stable, integral slag-coated layer 300 attached to the water-cooled wall 200. This structure fully utilizes the natural distribution characteristics of the molten materials within the furnace, achieving targeted protection for different materials and improving the overall stability of the slag-coated layer 300.

[0057] This embodiment designs the slag layer 300 in a longitudinal (or radial direction along the furnace shell 100) segmented manner according to the physicochemical properties of the molten material. This fully utilizes the protective function of the slag layer 300 for different molten materials, significantly enhances the furnace wall's resistance to erosion and scouring, optimizes the distribution of thermal stress and the heat conduction path, extends the service life of the furnace wall, reduces the maintenance frequency, and improves the operational safety and stability of the electric arc furnace in a high-temperature smelting environment.

[0058] In some embodiments, such as Figure 1 and Figure 3 As shown, along the depth direction of the furnace shell 100, the semi-solid protective layer 400 includes a semi-solid slag layer 410 and a semi-solid metal layer 420; the semi-solid slag layer 410 is formed by the molten slag 500A in the furnace contacting the solid slag layer 310 and then cooling; the semi-solid metal layer 420 is formed by the molten metal 500B in the furnace contacting the solid metal layer 320 and then cooling. In the radial direction of the furnace shell 100, the semi-solid metal layer 420 is arranged adjacent to the solid metal layer 320, and the semi-solid slag layer 410 is arranged adjacent to the solid slag layer 310.

[0059] Specifically, due to the differences in physicochemical properties between molten slag 500A and molten metal 500B, and the slag layer 300 structure formed in the previous embodiments, molten slag 500A has higher viscosity and stronger chemical corrosivity, while molten metal 500B has higher density and stronger fluidity. In its natural distribution within the furnace, molten slag 500A lies above molten metal 500B, forming a longitudinally layered structure. Therefore, along the depth direction of the furnace shell 100, the upper semi-solid slag layer 410 is formed longitudinally adjacent to the solid slag layer 310, and the lower semi-solid metal layer 420 is formed longitudinally adjacent to the solid metal layer 320. This segmentation conforms to the natural distribution pattern of the molten material and is beneficial to the stability of the interlayer structure.

[0060] Furthermore, by arranging a semi-solid slag layer 410 adjacent to a solid slag layer 310 and a semi-solid metal layer 420 adjacent to a solid metal layer 320 along the radial direction of the furnace shell 100, a gradient transition of thermal stress and mechanical buffering can be achieved. A significant temperature gradient exists in the radial direction within the furnace wall, so the molten material does not immediately solidify completely upon contact with the slag layer 300, but rather forms a semi-solid state. The semi-solid layer possesses a certain degree of plasticity, allowing for slight deformation under the influence of high-temperature molten material flow and thermal expansion, thus alleviating interlayer thermal stress, reducing the risk of cracking and spalling, and thereby enhancing the overall stability and adhesion of the slag layer 300.

[0061] It should also be noted that the semi-solid slag layer 410 and the semi-solid metal layer 420 are closely adjacent to their corresponding solid layers in both the longitudinal and radial directions, forming a continuous hard-soft composite structure in the protective layer: the solid layer provides high-strength mechanical fixation and chemical protection, while the semi-solid layer provides flexible buffering and thermal stress absorption. Furthermore, the adjacency between the two layers ensures stable interlayer bonding, while enabling the furnace wall to adapt to the flow of molten material and local temperature fluctuations, maintaining the integrity and protective function of the overall structure.

[0062] This embodiment segments the semi-solid protective layer 400, making full use of the natural distribution and semi-solid characteristics of the molten material to achieve interlayer gradient transition and buffer protection. This maintains the erosion resistance of the slag layer 300 while improving the furnace wall's resistance to thermal stress and erosion.

[0063] In some embodiments, such as Figure 1 , Figure 3 and Figure 4 As shown, along the radial direction of the furnace shell 100, the solid metal layer 320 includes a first metal protective layer 321 and a second metal protective layer 322; the first metal protective layer 321 is directly attached to the surface of the water-cooled wall 200.

[0064] Specifically, during the smelting process in the electric arc furnace, molten slag 500A undergoes a reduction reaction to generate molten metal 500B. Under the influence of gravity, molten metal 500B settles to the bottom of the furnace and gradually rises in level. It first contacts the solid slag layer 310, causing melting or displacement of the slag layer in a localized area. Subsequently, molten metal 500B further contacts the surface of the water-cooled wall 200. Due to the forced cooling effect of the water-cooled wall 200, molten metal 500B rapidly solidifies at the contact interface, forming a first metal protective layer 321 that adheres tightly to the surface of the water-cooled wall 200.

[0065] The first metal protective layer 321 is directly attached to the surface of the water-cooled wall 200, serving to construct a robust metal barrier to prevent the molten metal 500B from directly scouring and thermally eroding the water-cooled wall 200. Subsequently, a second metal protective layer 322 is further formed in the radial direction, serving as a transition layer between the first metal protective layer 321 and the semi-solid metal layer segment 420, providing buffering and stress dispersion functions. This layered design utilizes the natural gradient during the metal solidification process, allowing different metal layers to form stable adhesion according to the cooling rate and contact pressure, while reducing interfacial stress caused by differences in thermal expansion.

[0066] Furthermore, through the synergistic effect of the first metal protective layer 321 and the second metal protective layer 322, the solid metal layer 320 forms a multi-layer protective composite structure in the radial direction of the furnace shell 100: the first metal protective layer 321 provides a high-strength direct barrier, the second metal protective layer 322 plays a role in stress buffering and structural transition, while the semi-solid metal layer 420 further absorbs thermal stress and adapts to the flow of molten metal 500B.

[0067] In this embodiment, by setting a first metal protective layer 321 and a second metal protective layer 322 along the radial direction of the furnace shell 100, a stable and erosion-resistant metal barrier can be formed on the surface of the water-cooled wall 200. At the same time, thermal stress buffering and structural transition are achieved, effectively preventing molten metal 500B from eroding the water-cooled wall 200, enhancing the durability of the furnace wall, extending the service life of the furnace lining, and improving the safety and stability of the electric arc furnace in a high-temperature smelting environment.

[0068] In some embodiments, such as Figure 1 , Figure 3 and Figure 4 As shown, along the radial direction of the furnace shell 100, the hardness of the first metal protective layer 321, the second metal protective layer 322, and the semi-solid metal layer 420 decreases sequentially; and / or, Along the radial direction of the furnace shell 100, the hardness of the solid slag layer 310 and the semi-solid slag layer 410 decreases sequentially.

[0069] Specifically, after molten metal 500B settles to the bottom of the furnace and gradually rises in level, it first contacts the solid slag layer 310, and then further contacts the surface of the water-cooled wall 200. The forced cooling effect of the circulating cooling water inside the water-cooled wall 200 causes the molten metal 500B to solidify rapidly upon contact with the water-cooled wall 200, forming the first metal protective layer 321. Due to the rapid solidification rate and intense cooling, the metal grains are fine and the structure is compact, resulting in high hardness.

[0070] Outside the first metal protective layer 321, molten metal 500B is sequentially cooled to form a second metal protective layer 322 and a semi-solid metal layer 420. Compared to the first metal protective layer 321, which is directly attached to the water-cooled wall 200, the second metal protective layer 322 and the semi-solid metal layer 420 have a slower cooling rate, longer grain growth time, and a relatively loose structure, resulting in lower hardness. Simultaneously, the second metal protective layer 322 and the semi-solid metal layer 420 are located inside the protective layer, directly bearing less erosion force and thermal load. Therefore, they do not need to maintain excessively high hardness, and the lower hardness provides a certain degree of plastic buffer, which is beneficial for absorbing thermal expansion and local stress, thereby reducing the risk of cracking or spalling.

[0071] Through the aforementioned hardness gradient design, the furnace wall forms a composite structure with different hardnesses along the radial direction: the first metal protective layer 321 acts as a robust barrier to provide direct erosion and thermal load protection, while the second metal protective layer 322 and the semi-solid metal segment 420 serve as buffers and stress transitions. The decreasing hardness between layers ensures that the furnace wall surface can withstand the erosion of molten metal 500B, while also providing flexible buffering for the internal protective layers, thus improving overall stability.

[0072] Similarly, the solid slag layer 310 near the water-cooled wall 200 has a higher hardness, which can resist the chemical erosion and local scouring of the molten slag 500A; the semi-solid slag layer 410 towards the outside has a lower hardness, maintaining a certain degree of plasticity, which can buffer the impact of slag flow and thermal stress, while forming a gradient transition with the solid slag layer, achieving a stable overall adhesion of the slag layer. The hardness gradient design gives the protective layer both sufficient strength to resist erosion and flexible buffering capacity, optimizes the distribution of thermal stress, and improves the stability of interlayer bonding.

[0073] This embodiment sets a hardness gradient along the radial direction of the furnace shell 100, so that the high-hardness layer resists direct erosion and local high-temperature corrosion, while the low-hardness layer absorbs thermal stress and minor deformation, thereby achieving stable adhesion and gradient transition of the protective layer structure, thus extending the service life of the furnace wall and reducing the maintenance frequency.

[0074] In some embodiments, such as Figure 1 and Figure 3As shown, the water-cooled wall 200 is divided into at least two independent cooling zones along the depth direction of the furnace shell 100. The cooling intensity of each cooling zone is different, and the cooling intensity of the cooling zone located near the bottom of the furnace shell 100 is greater than that of the other cooling zones.

[0075] Specifically, since the molten metal 500B deposited in the furnace bottom area and subjected to gravity to scour the water-cooled wall 200 has a high intensity and a high local heat load, a stronger cooling capacity is required to quickly remove heat, reduce the local temperature, and prevent the water-cooled wall 200 and the adjacent solid metal layer 320 from overheating and premature failure.

[0076] In contrast, the cooling zones near the top or middle of the furnace are primarily affected by the molten slag 500A, rather than being directly scoured by the non-molten metal 500B. The scouring force and localized heat load are lower in these zones, allowing for a reduction in cooling intensity. This not only avoids thermal stress concentration caused by excessive cooling but also reduces energy consumption. By distributing the cooling intensity in a gradient along the longitudinal direction of the furnace shell 100, the water-cooled wall 200 can implement temperature control strategies for different areas, achieving focused cooling of the high-temperature bottom zones and moderate protection of the medium- and low-temperature upper zones, thereby improving the overall thermal stability of the furnace wall structure.

[0077] Furthermore, the zoned cooling design helps optimize the solidification process of the slag layer 300 and the solid / semi-solid protective layer 400. When the bottom cooling intensity is high, the molten metal 500B rapidly solidifies on the surface of the water-cooled wall 200 to form a dense first metal protective layer 321, enhancing its hardness and erosion resistance. When the upper cooling intensity is low, the molten slag 500A cools slowly on the surface of the solid and semi-solid slag layers, forming a moderately flexible protective layer, which is beneficial for thermal expansion absorption and stress regulation, thus achieving overall stability of the slag layer 300.

[0078] This embodiment sets up multiple cooling zones along the depth direction of the furnace shell 100 and adjusts the cooling intensity, which can carry out differentiated thermal management for the temperature and molten material characteristics of different areas, thereby effectively reducing the local temperature of the high temperature zone at the bottom of the furnace and the contact surface of the molten metal 500B, while optimizing the thermal stress distribution and extending the overall service life of the furnace wall.

[0079] In some embodiments, such as Figure 1 , Figure 3 and Figure 5 As shown, the structural parameters of the plurality of slag hanging troughs 210 increase in a gradient along the depth direction of the furnace shell 100, and the structural parameters include at least one of the following: trough depth, trough width, or cross-sectional angle.

[0080] Specifically, the molten metal 500B in the furnace bottom area has a high density and strong fluidity, and also experiences high local scouring force; the furnace top or upper middle part is mainly affected by the molten slag 500A, which has relatively low fluidity and weak scouring intensity. Therefore, setting a larger depth, width, or wider cross-sectional angle in the lower part of the slag-hanging trough 210 can enhance the capture and adhesion ability of the molten metal 500B and slag in the trough, and improve the stability and self-generating protective effect of the slag-hanging layer 300.

[0081] Furthermore, by setting slag-hanging grooves 210 with increasing gradients along the depth direction of the furnace shell 100, the solidification and deposition process of the slag layer 300 can be optimized. The larger bottom groove facilitates the rapid cooling of molten metal 500B to form a dense solid metal layer 320, while providing stable support for the semi-solid metal layer 420; the smaller upper groove accommodates the lower scouring intensity of molten slag 500A and ensures that the slag liquid can be uniformly adhered to the surface of the water-cooled wall 200, thereby forming a continuous and dense solid slag layer 310 and semi-solid slag layer 410. Through gradient design, slag-hanging grooves 210 of different depths can achieve a zoned protection strategy that allows the deep grooves to withstand strong scouring and the shallow grooves to meet the light scouring, taking into account the characteristics of different molten materials.

[0082] Furthermore, the gradient-increased slag-hanging trough 210 structure is beneficial for thermal stress buffering and hydrodynamic stability. The gradual changes in trough depth, trough width, and cross-sectional angle can alter the flow path and local cooling rate of the molten material within the trough, allowing the solid and semi-solid protective layers 400 to form a natural gradient along the longitudinal direction of the furnace shell 100. This prevents cracking or peeling due to stress concentration and enhances the overall adhesion and stability of the protective layer.

[0083] In this embodiment, by setting a slag-hanging groove 210 with a gradient increase along the depth direction of the furnace shell 100, the slag-hanging layer 300 can be stably attached and self-generated for protection based on the scouring and heat load characteristics of molten material in different depth areas, thereby optimizing the thermal stress distribution, improving the overall service life of the furnace wall, and reducing the frequency of furnace shutdown for maintenance.

[0084] In some embodiments, such as Figure 1 As shown, the top of the furnace shell 100 is provided with a furnace cover for sealing the accommodating space 110, and the furnace cover is provided with a feeding port 600; the feeding port 600 is located at a position 0.5m to 2m from the edge of the furnace cover, or in other words, the distance between the feeding port 600 and the side wall of the water-cooled wall 200 along the radial direction of the furnace shell 100 is 0.5m to 2m.

[0085] By positioning the feed port 600 close to the furnace wall, the material sinks along the furnace wall after being fed and enters the slag layer, thereby forming a relatively low-temperature material accumulation zone in the furnace wall area. During contact with the water-cooled wall 200, the calcined sand or solid material in this zone can form an additional protective layer on the water-cooled wall 200, reducing the heat load on the surface of the water-cooled wall 200 and the direct scouring effect of the molten material.

[0086] Meanwhile, during the smelting process, as the flow of the melt inside the furnace tends to stabilize, the furnace wall area is more likely to form and maintain a stable slag layer 300, thereby enhancing the adhesion stability of the slag layer 300 on the surface of the water-cooled wall 200 and further improving the protection effect on the water-cooled wall 200.

[0087] In some embodiments, such as Figure 5 As shown, the water-cooled wall 200 includes an inlet 220 and an outlet 230, and is equipped with a temperature sensor or a temperature detection system.

[0088] By monitoring the inlet and outlet temperatures of the circulating cooling water within the water-cooled wall 200 and the hot surface temperature of the water-cooled wall 200 in real time, the heat exchange status of the water-cooled wall 200 and the formation and changes of its surface deposits (such as the slag layer 300 and its metal protective layer) can be dynamically reflected. When abnormal temperature fluctuations are detected, the operating conditions of the electric furnace can be adjusted in a timely manner, such as adjusting the feeding rhythm, current parameters, or cooling water flow rate, thereby avoiding local overheating or deposit instability.

[0089] By combining the above-mentioned structure with monitoring methods, not only can the distribution of materials in the furnace be optimized and the self-generating protection capability of the furnace wall area be enhanced, but also the real-time perception and control of the operating status of the water-cooled wall 200 can be achieved, thereby ensuring the long-term stable operation of the electric arc furnace in a high-temperature smelting environment.

[0090] Based on the same inventive concept, this application also provides a slag-coating method for preparing the furnace wall of a submerged arc furnace as described above, the method comprising: A submerged arc furnace body is provided with a water-cooled wall 200, and a cooling medium is introduced into the water-cooled wall 200 to keep the water-cooled wall 200 at a low temperature. During the heating stage, the material inside the furnace is heated to gradually melt and form molten slag 500A. When the molten slag 500A comes into contact with the surface of the water-cooled wall 200, it cools down and adheres under the cooling effect of the water-cooled wall 200. A slag layer 300 and a semi-solid protective layer 400 are formed sequentially on the surface of the water-cooled wall 200 along the radial direction of the furnace shell 100. During the smelting stage of the electric arc furnace, molten slag 500A undergoes a reduction reaction to generate molten metal 500B. Under the action of gravity, the molten metal 500B settles towards the bottom of the furnace and gradually rises to the liquid level. The molten metal 500B first contacts the solid slag layer 310 and locally melts or replaces the solid slag layer 310. When the molten metal 500B further contacts the water-cooled wall 200, it solidifies under the action of cooling, and a first metal protective layer 321, a second metal protective layer 322, and a semi-solid metal layer 420 are sequentially formed at the contact interface along the radial direction of the furnace shell 100. The first metal protective layer 321 has a higher hardness than the second metal protective layer 322, and the second metal protective layer 322 has a higher hardness than the semi-solid metal segment 420.

[0091] Specifically, the slag-coating method in this embodiment first involves providing a submerged arc furnace body equipped with a water-cooled wall 200, and then introducing a cooling medium into the interior of the water-cooled wall 200 to create a stable circulating cooling system, thereby maintaining its surface at a relatively low temperature. This method establishes a stable cooling interface on the surface of the water-cooled wall 200, creating conditions for the rapid cooling and adhesion of subsequent molten materials, while ensuring that the water-cooled wall 200 has continuous heat exchange capacity without localized overheating.

[0092] During the heating phase, the material inside the furnace is continuously heated, gradually increasing the furnace temperature to approximately 1550°C to 1600°C, and maintaining operation within this temperature range. As the temperature rises, the material inside the furnace gradually melts to form molten slag 500A. When the molten slag 500A comes into contact with the surface of the water-cooled wall 200, it rapidly cools down under the cooling effect of the water-cooled wall 200, reducing its fluidity and causing adhesion and solidification, thereby forming an initial slag layer 300 on the surface of the water-cooled wall 200. With the continuous replenishment of molten slag 500A, a semi-solid protective layer 400 gradually forms on the outside of the slag layer 300, so that the slag layer 300 and the semi-solid protective layer 400 are sequentially formed along the radial direction of the furnace shell 100. In the above process, the material inside the furnace is heated from room temperature to a stable operating temperature, and a stable slag structure is gradually established. The overall heating phase usually lasts for a relatively long time, for example, about 10 days, to allow the slag layer 300 and the semi-solid protective layer 400 to form and reach a stable state.

[0093] It should be noted that when the furnace temperature reaches a stable level (1550℃ to 1600℃) and the water-cooled wall 200 provides continuous cooling, the local solidification process of the molten slag 500A on the surface of the water-cooled wall 200 has a relatively fast response characteristic. That is, in a local area, the slag layer 300 and the semi-solid protective layer 400 on its outer side can be formed rapidly in a short time, for example, it can be formed and cover the water-cooled wall 200 in about 20 minutes.

[0094] The process then proceeds to the submerged arc furnace smelting stage, where the furnace temperature is maintained at approximately 1550°C to 1600°C, but the reaction is primarily reduction-based and lasts for a relatively short period (e.g., 24 hours). Molten slag 500A generates molten metal 500B during the reaction. This molten metal 500B settles towards the bottom of the furnace under gravity and gradually rises to the surface. During this process, the molten metal 500B first contacts the already formed solid slag layer 310, causing localized erosion or displacement. When the molten metal 500B further contacts the surface of the water-cooled wall 200, it rapidly solidifies under cooling, forming a first metal protective layer 321, a second metal protective layer 322, and a semi-solid metal layer 420 sequentially along the radial direction of the furnace shell 100.

[0095] In this process, the water-cooled wall 200 provides a decreasing cooling intensity from the inside out. The first metal protective layer 321 is formed under rapid cooling conditions, resulting in a dense structure and high hardness. The second metal protective layer 322 has a relatively low cooling rate and a slightly lower hardness. The semi-solid metal layer 420 is in a partially solidified state, possessing a certain degree of plasticity and exhibiting the lowest hardness. This creates a gradient structure with gradually decreasing hardness in the radial direction of the furnace wall. This gradient structure can both resist the scouring and erosion of the molten metal 500B through the high-hardness layer and absorb thermal stress and adapt to local deformation through the low-hardness layer, thereby improving the overall structural stability.

[0096] In this embodiment, the above method can be used to construct a multi-layer composite structure consisting of a slag layer 300 and a semi-solid protective layer 400 on the surface of the water-cooled wall 200 in situ. This structure can be dynamically maintained and self-repaired during subsequent operation, thereby effectively improving the furnace wall's resistance to erosion and service life, reducing maintenance frequency, and ensuring the long-term stable operation of the submerged arc furnace in a high-temperature smelting environment.

[0097] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0098] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0099] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0100] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0101] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0102] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A furnace wall for an electric arc furnace, c h a r a c t e r i s e d in that include: A furnace shell, the interior of which is provided with a receiving space; A water-cooled wall is located on the inner wall of the space within the furnace shell; The slag layer is located on the side of the water-cooled wall away from the furnace shell; A semi-solid protective layer is located on the side of the slag-coated layer away from the water-cooled wall; The slag layer and the semi-solid protective layer are both formed by the cooling of molten material in the furnace after contacting the water-cooled wall. The molten material includes molten slag and molten metal, and the slag layer is directly attached to the surface of the water-cooled wall.

2. The wall of an electric arc furnace according to claim 1, characterized in that The surface of the water-cooled wall away from the furnace shell is provided with multiple slag-hanging grooves that are recessed into the water-cooled wall, and the depth of the recessed slag-hanging grooves is less than the thickness of the water-cooled wall; and / or, The surface of the water-cooled wall away from the furnace shell is provided with a plurality of slag-hanging grooves that are recessed into the interior of the water-cooled wall. The depth of the slag-hanging grooves is related to the thermal conductivity of the slag; the higher the thermal conductivity, the deeper the slag-hanging grooves, and vice versa.

3. The furnace wall of the submerged arc furnace according to claim 2, characterized in that, The cross-sectional shape of the slag-hanging trough includes any one or more combinations of rectangle, square, triangle, or trapezoid, and the plurality of slag-hanging troughs are either intersecting or spaced apart along the same direction; or, The slag-hanging trough has a dovetail groove structure.

4. The furnace wall of the submerged arc furnace according to claim 1, characterized in that, Along the depth direction of the furnace shell, the slag layer includes a solid slag layer section and a solid metal layer section; the solid slag layer section is formed by the solidification and adhesion of molten slag in the furnace after contacting the water-cooled wall and under cooling action; the solid metal layer section is formed by the solidification of molten metal in the furnace after contacting the water-cooled wall and under cooling action. The solid metal layer is located in a region near the bottom of the furnace shell.

5. The furnace wall of the submerged arc furnace according to claim 4, characterized in that, Along the depth direction of the furnace shell, the semi-solid protective layer includes a semi-solid slag layer and a semi-solid metal layer; the semi-solid slag layer is formed by the molten slag in the furnace coming into contact with the solid slag layer and then being cooled; the semi-solid metal layer is formed by the molten metal in the furnace coming into contact with the solid metal layer and then being cooled. In this configuration, along the radial direction of the furnace shell, the semi-solid metal layer is arranged adjacent to the solid metal layer, and the semi-solid slag layer is arranged adjacent to the solid slag layer.

6. The furnace wall of the submerged arc furnace according to claim 5, characterized in that, Along the radial direction of the furnace shell, the solid metal layer includes a first metal protective layer and a second metal protective layer; the first metal protective layer is directly attached to the surface of the water-cooled wall.

7. The furnace wall of the submerged arc furnace according to claim 6, characterized in that, Along the radial direction of the furnace shell, the hardness of the first metal protective layer, the second metal protective layer, and the semi-solid metal layer decreases sequentially; and / or, Along the radial direction of the furnace shell, the hardness of the solid slag layer and the semi-solid slag layer decreases sequentially.

8. The furnace wall of the submerged arc furnace according to any one of claims 1-7, characterized in that, The water-cooled wall is divided into at least two independent cooling zones along the depth direction of the furnace shell. Each cooling zone has a different cooling intensity, and the cooling intensity of the cooling zone located near the bottom of the furnace shell is greater than that of the other cooling zones.

9. The furnace wall of the submerged arc furnace according to any one of claims 2-3, characterized in that, The structural parameters of the plurality of slag hanging troughs increase in a gradient along the depth direction of the furnace shell, and the structural parameters include at least one of the following: trough depth, trough width, or cross-sectional angle.

10. A method for coating slag, characterized in that, The method is applied to the preparation of the furnace wall of a submerged arc furnace as described in any one of claims 1-9, and comprises: A submerged arc furnace body is provided, and a cooling medium is introduced into the interior of the water-cooled wall to keep the water-cooled wall at a low temperature. During the heating stage, the material inside the furnace is heated so that it gradually melts to form molten slag. When the molten slag comes into contact with the surface of the water-cooled wall, it cools down and adheres under the cooling effect of the water-cooled wall, forming a slag layer and a semi-solid protective layer on the surface of the water-cooled wall in the radial direction of the furnace shell. During the smelting stage of the electric arc furnace, the molten slag undergoes a reduction reaction to generate molten metal. Under the action of gravity, the molten metal settles towards the bottom of the furnace and gradually rises to the liquid level. The molten metal first contacts the solid slag layer in the slag layer and locally melts or replaces the solid slag layer. When the molten metal further contacts the water-cooled wall, it solidifies under the action of cooling, and a first metal protective layer, a second metal protective layer, and a semi-solid metal layer are formed sequentially along the radial direction of the furnace shell at the contact interface. Wherein, the hardness of the first metal protective layer is greater than the hardness of the second metal protective layer, and the hardness of the second metal protective layer is greater than the hardness of the semi-solid metal layer segment.

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