Gradient cooling multilayer metal composite blast furnace water jacket and preparation method thereof

Abstract

The invention discloses a gradient cooling multilayer metal blast furnace composite water jacket and a preparation method thereof, and belongs to the technical field of lead and zinc smelting. The water jacket comprises a multi-layer metal composite plate formed by welding a contact layer, a heat exchange layer and a substrate layer in a weldless mode. A rectangular slag tap is formed in the bottom of the composite water jacket along the central axis of the composite water jacket; s-shaped cooling pipelines are arranged in the heat exchange layer, and the pipeline distance of the cooling pipelines is increased from the end close to the slag discharging opening to the end away from the slag discharging opening. The preparation process of the water jacket comprises the steps that the multi-layer metal composite plate is obtained through weldless welding, then the multi-layer metal composite plate penetrates into the heat exchange layer from one side of the base layer through machining, the S-shaped cooling pipeline is formed, then the base layer is complemented, only a cooling pipeline port is reserved, and heat treatment is conducted. The water jacket is based on a multi-layer composite structure and has washing resistance, high heat conductivity and strong pressure bearing performance, and through the cooling water channels distributed in the heat transfer layer in a gradient mode, a dead water area is thoroughly eliminated, and the technical problem that a traditional cavity structure is uneven in cooling is solved.

Description

Technical Field

[0001] This invention relates to a cooling water jacket for a blast furnace, specifically to a gradient cooling multilayer metal blast furnace composite water jacket and its preparation method, belonging to the field of lead-zinc smelting technology. Background Technology

[0002] In the treatment of lead-zinc smelting slag, the blast furnace is the core processing equipment, and its structural and process stability during operation is directly related to the performance of the cooling water jacket. On the one hand, the cooling water jacket can absorb heat from the furnace wall through circulating cooling water, preventing the steel plates from deforming or burning through due to high temperatures inside the furnace; on the other hand, it can directly affect the airflow distribution and charge movement inside the furnace through the cooling rate, thereby effectively balancing the uniformity of airflow and reducing the risk of furnace slagging.

[0003] The cooling water jackets used in existing technologies are generally hollow steel structures attached to the inside of the furnace body, with cooling water circulating within the cavity to achieve cooling. They have advantages such as simple structure and low cost, and are widely used in industry. However, this type of water jacket still has many problems, mainly manifested in:

[0004] 1. Structural stability: Since the hollow steel structure is a cuboid structure, it is very easy for uneven water level to occur due to resistance difference when used in parallel. When air is mixed in, it is easy to cause water jacket vibration, which may lead to water jacket damage or detachment in severe cases.

[0005] 2. Cooling efficiency stability: The cavity structure of the hollow steel water jacket creates dead water zones in the circulating cooling water. On the one hand, this leads to the accumulation of scale in the dead zones, reducing cooling efficiency. On the other hand, it also causes uneven heating and large temperature differences inside the water jacket, generating significant thermal stress and reducing material life. In addition, the material of the hollow steel water jacket is mostly structural steel, which has poor thermal conductivity. When the molten material washes over the water, it cannot cool quickly to form a protective slag layer, which further reduces cooling efficiency and aggravates water jacket wear.

[0006] 3. Material stability: During the metallurgical process, the molten material is violently stirred when the air is blown in, which directly and strongly erodes the tuyeres of the steel jacket. Under the action of internal thermal stress and external erosion, the surface of the jacket suffers high wear, which can lead to perforation and leakage in severe cases.

[0007] In summary, the advantages of existing technologies are only simple structure and low manufacturing cost, but they cannot meet the needs of industrial development in terms of erosion resistance, thermal conductivity, cooling uniformity, and critical service life. Summary of the Invention

[0008] To address the problems existing in the prior art, the first objective of this invention is to provide a gradient-cooled multilayer metal composite blast furnace water jacket. This composite water jacket employs a three-layer composite structure, combining erosion resistance, high thermal conductivity, and strong pressure resistance, overcoming the performance limitations of traditional single-material water jackets. It features gradient-distributed serpentine cooling channels within the heat transfer layer, completely eliminating dead water zones while achieving uniform cooling of the entire composite plate, thus solving the technical problem of uneven cooling in traditional cavity structures.

[0009] The second objective of this invention is to provide a method for preparing a gradient-cooled multilayer metal composite blast furnace water jacket. This method achieves a tight bond between the multilayer metal composite plates through a seamless welding process, ensuring interlayer heat transfer efficiency and structural stability while effectively preventing interlayer delamination. Furthermore, cooling pipes are laid from one side of the base layer via mechanical processing, ensuring the integrity of the contact surface. The contact layer can quickly form a dense slag layer upon contact with the molten material, further isolating it from molten material erosion, thus achieving a dual effect of "active cooling + passive protection."

[0010] To achieve the above-mentioned technical objectives, the present invention provides a gradient cooling multilayer metal blast furnace composite water jacket, comprising a multilayer metal composite plate composed of a contact layer, a heat exchange layer and a base layer welded together without weld seams; a rectangular slag discharge port is provided at the bottom of the composite water jacket along its central axis; a serpentine cooling pipe is provided in the heat exchange layer, and the spacing between the cooling pipes increases from the end closer to the slag discharge port to the end farther away from the slag discharge port.

[0011] The composite water jacket provided by this invention first refines the materials used into a contact layer, a heat exchange layer, and a base layer. Through seamless welding, it simultaneously improves the anti-erosion properties, high thermal conductivity, and strong pressure resistance. Furthermore, the distribution of the serpentine cooling pipes in the heat exchange layer is not a traditional uniform distribution, but a gradient bending distribution. The pipe density is increased in the heat-intensive areas and decreased in the heat-sparse areas. This not only completely eliminates the dead water zone of the water jacket, but also fundamentally solves the technical problems of uneven heating and cooling of the water jacket.

[0012] As a preferred embodiment, the contact layer is made of a corrosion-resistant metal material, the heat exchange layer is made of a thermally conductive metal material, and the base layer is made of a pressure-resistant metal material.

[0013] As a preferred embodiment, the outer side of the base layer is also provided with reinforcing ribs.

[0014] As a preferred embodiment, the contact layer material is at least one of Hastelloy, alloy 625, and alloy C276. More preferably, the contact layer material is alloy 625.

[0015] As a preferred embodiment, the heat exchange layer is at least one selected from copper, oxygen-free copper, aluminum, and silver. More preferably, the heat exchange layer is copper.

[0016] As a preferred embodiment, the base layer is structural steel. More preferably, the base layer is carbon steel.

[0017] As a preferred embodiment, the thickness of the contact layer is 5-10 mm; the thickness of the heat exchange layer is 70-90 mm; and the thickness of the base layer is 10-30 mm.

[0018] The composite water jacket provided by this invention achieves improved erosion resistance, thermal conductivity, and pressure resistance through the synergistic effect of its three-layer composite structure. Among them, the contact layer directly faces the erosion of the melt, therefore, it needs to have high temperature resistance, corrosion resistance, and microstructural stability to avoid damage or detachment due to internal stress and erosion kinetic energy. In addition, since the contact layer mainly shares the influence of the erosion kinetic energy and thermal energy of the melt, its thickness must also be strictly controlled within the above requirements. Too thick a layer will lead to a decrease in heat transfer performance, while too thin a layer will be unable to withstand high-intensity erosion kinetic energy.

[0019] In the three-layer composite structure, the heat transfer layer is the core structure of the water jacket cooling system. It needs to have excellent thermal conductivity and stable thermochemical properties, and its thickness is the thickest of the three layers to facilitate rapid heat exchange within the blast furnace. The base layer is the substrate of the composite structure, which supports the water jacket and connects the blast furnace. Since it does not directly face the melt, its main characteristic is its strong pressure-bearing capacity. In addition, it should be noted that in order to ensure the structural stability of the composite structure facing the melt surface, the laying of the gradient distributed cooling pipes needs to be milled from the base layer to the heat transfer layer. Therefore, the heat transfer layer and the base layer also need to have excellent machinability.

[0020] As a preferred embodiment, the diameter of the serpentine cooling pipe is 40-60% of the thickness of the heat exchange layer.

[0021] As a preferred embodiment, the ratio of the pipe spacing to the diameter of the serpentine cooling pipe is 2 to 8:1.

[0022] As a preferred embodiment, the composite water jacket is a tetragonal prism in shape.

[0023] As a preferred embodiment, the length of the rectangular slag discharge port is 30-40% of the side length of the composite water jacket near the metallurgical melt, and the width is 30-40% of the width of the composite water jacket.

[0024] This invention also provides a method for preparing a gradient cooling multilayer metal blast furnace composite water jacket. The process is as follows: a contact layer, a heat exchange layer, and a base layer are welded together without welds to obtain a multilayer metal composite plate. A serpentine cooling pipe is formed by machining from one side of the base layer into the heat exchange layer. Then, the base layer is completed using the same material as the base layer, leaving only the cooling pipe port. Inlet and outlet water ports are set at the port to form a multilayer metal composite water jacket precursor. Reinforcing ribs are set in the base layer of the precursor, and after heat treatment, the product is obtained.

[0025] This invention uses a seamless welding method to obtain a multi-layer metal composite plate, which not only ensures uniform heat transfer between layers, but also improves structural uniformity and stability, effectively avoiding the problem of interlayer delamination. In addition, by machining one side of the base layer to open a serpentine cooling channel, not only is the integrity of the contact layer guaranteed, but the processing cost of the serpentine channel is also greatly reduced.

[0026] As a preferred embodiment, the seamless welding is one of gas shielded welding, explosive welding, and cumulative roll welding. Seamless welding enables a tight bond between the layers of the multilayer metal composite plate, with interlayer bonding strength comparable to that of a single-piece molding. This effectively controls manufacturing costs while significantly reducing internal thermal stress in the composite metal plate.

[0027] As a preferred embodiment, when the seamless welding is explosive welding, the process is as follows: after the three plates of the same length and width are laid flat, the explosive is evenly spread on the outer surface of the contact layer and detonated through the end of the detonator or detonating cord.

[0028] As a preferred embodiment, the explosive is a low-detonation-velocity explosive comprising the following components by mass percentage: 64-75% expanded ammonium nitrate, 3-4% diesel oil, 2-3% powdered emulsion explosive, and 15-30% salt.

[0029] The explosive charge density is approximately 0.6~0.8 g / cm³, and the thickness is 50~70 mm.

[0030] As a preferred option, the method for completing the base layer is gas shielded welding.

[0031] The parameters for explosive welding must be strictly followed according to the above requirements. If too much explosive is loaded, it will cause cracks in the composite plate after welding. If too little explosive is loaded, it will result in insufficient welding and gaps between the layers.

[0032] As a preferred embodiment, the heat treatment conditions are as follows: under a protective atmosphere, the temperature is increased from room temperature to 650-760°C at a rate of 1-10°C / min, held at that temperature for 0.5-1.5 hours, and then cooled to room temperature in the furnace. The heat treatment process of this invention mainly aims to eliminate internal stress in the material. It is important to note that in order to protect the microstructural stability of the contact layer, the holding temperature and time must be strictly controlled to avoid prolonged exposure within the sensitization temperature range.

[0033] Compared with the prior art, the beneficial technical effects of the technical solution provided by the present invention are as follows:

[0034] 1) The composite water jacket provided by the present invention adopts a three-layer composite structure, which takes into account the erosion resistance, high thermal conductivity and strong pressure bearing performance, and breaks through the performance limitations of traditional single-material water jackets. It sets up a gradient distribution of serpentine cooling water channels in the heat transfer layer, which completely eliminates dead water areas and also achieves uniform cooling of the entire composite plate, solving the technical problem of uneven cooling of traditional cavity structures.

[0035] 2) The preparation method provided by the present invention uses a seamless welding process to tightly bond the multilayer metal composite plate, which ensures the heat transfer efficiency and structural stability between layers, while also effectively avoiding the problem of interlayer peeling; and cool pipes are laid from one side of the base layer by mechanical processing to ensure the integrity of the contact surface, so that it can quickly form a dense slag layer when in contact with the melt, further isolating the melt from scouring, and achieving the dual effect of "active cooling + passive protection". Attached Figure Description

[0036] Figure 1 The three views are of the gradient cooling multilayer metal blast furnace composite water jacket provided in Embodiment 1 of the present invention;

[0037] Figure 2 This is a cross-sectional view of section AA in the composite water jacket of the gradient cooling multilayer metal blast furnace provided in Embodiment 1 of the present invention;

[0038] Figure 3 This is a cross-sectional view of the BB section in the composite water jacket of the gradient cooling multilayer metal blast furnace provided in Embodiment 1 of the present invention. Detailed Implementation

[0039] The present invention will be further explained and described below with reference to specific embodiments, including more detailed implementation methods and operational details. The purpose of providing these embodiments is not to limit the scope of the present invention; rather, the embodiments are based on the technical solutions of the present invention and are merely illustrative, intended to provide a detailed explanation for a better understanding of the content of the present invention.

[0040] Those skilled in the art can make various modifications and improvements based on the disclosure of this invention. Without departing from the overall concept and purpose of this invention, such modifications and improvements should be protected by this invention.

[0041] Example 1

[0042] This embodiment provides a gradient cooling multilayer metal composite blast furnace water jacket, the structure of which is as follows: Figure 1 As shown, it includes a multi-layer metal composite plate composed of a contact layer, a heat exchange layer and a base layer welded together without weld seams; a rectangular slag discharge port is provided at the bottom of the composite water jacket along its central axis; a serpentine cooling pipe is provided in the heat exchange layer, and the pipe spacing of the cooling pipe increases from the end closer to the slag discharge port to the end farther away from the slag discharge port;

[0043] The contact layer is 5mm thick and made of 625 alloy, conforming to ASTM B443 material standard.

[0044] The heat exchange layer is 80 μm thick, made of copper, and conforms to the T2 material standard.

[0045] The thickness of the base layer is 20mm, and the material is carbon steel, with a material standard of Q235R.

[0046] The composite water jacket is a quadrangular prism with a trapezoidal cross-section in its front view. The upper side is 1516.7 mm long, the lower side is 1250 mm long, and the height is 800 mm. The slag discharge port is located at the central axis of the lower side, with a width of 420 mm and a height of 280 mm.

[0047] The serpentine cooling pipe has a diameter of 30mm, and its pipe spacing is distributed in a gradient, increasing from the end closer to the slag discharge port to the end farther away from the slag discharge port. The pipe spacing is 60mm, 60mm, 60mm, 130mm, 140mm, 230mm and 360mm respectively.

[0048] The method for preparing the gradient cooling multilayer metal blast furnace composite water jacket provided in this embodiment specifically includes: obtaining a multilayer metal composite plate by explosive welding of a contact layer, a heat exchange layer, and a base layer; machining a serpentine cooling pipe extending from one side of the base layer into the heat exchange layer; then completing the base layer using the same material as the base layer, leaving only the cooling pipe port, and setting inlet and outlet water outlets at the port to obtain a multilayer metal composite water jacket precursor; setting reinforcing ribs in the base layer of the precursor, and heat treating it to obtain the final product;

[0049] The explosive is a low-detonation-velocity explosive, comprising the following components by mass percentage: 70% expanded ammonium nitrate, 3% diesel oil, 2% powdered emulsion explosive, and 25% salt; the explosive charge density is approximately 0.7 g / cm³, and the thickness is 60 mm; the base layer is completed by gas shielded welding; the heat treatment conditions are: under a protective atmosphere, the temperature is increased from room temperature to 670°C at a rate of 3°C / min, held for 0.5 h, and then cooled to room temperature in the furnace.

[0050] Comparative Example 1

[0051] The water jacket provided in this comparative example is exactly the same as that in Example 1, except that: 1) carbon steel is used to replace the multi-layer metal composite plate; 2) instead of laying serpentine pipes, a whole cavity with a spacing of 30mm is used.

[0052] After preparation, the water jackets obtained in Example 1 and Comparative Example 1 were subjected to a water pressure test. The test pressure was 1 MPa, and the test process was as follows: the pressure was slowly increased to the test pressure, and the pressure was maintained for no less than 30 minutes. The water pressure test results showed that the water jacket obtained in Example 1 had no leakage, deformation, or abnormal noise, while the water jacket obtained in Comparative Example 1, although it had no leakage or deformation, had abnormal noise at a pressure of 1 MPa. As the pressure decreased, the abnormal noise gradually disappeared.

[0053] The present invention conducted thermal conductivity tests on the water jackets obtained in Example 1 and Comparative Example 1. The thermal conductivity of the water jacket obtained in Example 1 was improved by 650% compared to that in Comparative Example 1, and there were no dead water zones during operation. Furthermore, the present invention also conducted lifespan tests on the water jackets obtained in Example 1 and Comparative Example 1. The water jacket obtained in Comparative Example 1 experienced severe local temperature surges after 60 days of continuous operation under standard blast furnace conditions, rendering it unusable and requiring shutdown for maintenance. In contrast, the water jacket obtained in Example 1 of the present invention operated continuously for at least 380 days under standard blast furnace conditions before entering the normal shutdown and maintenance phase. If calculated on an annual basis, replacing the water jacket in Comparative Example 1 with the composite water jacket obtained in Example 1 would reduce the equipment maintenance cost of each blast furnace by approximately 800,000 yuan.

Claims

1. A composite water jacket for a gradient-cooled multilayer metal blast furnace, characterized in that: It includes a multi-layer metal composite plate consisting of a contact layer, a heat exchange layer, and a base layer welded together without weld seams; a rectangular slag discharge port is provided at the bottom of the composite water jacket along its central axis; a serpentine cooling pipe is provided in the heat exchange layer, and the spacing between the cooling pipes increases from the end closer to the slag discharge port to the end farther away from the slag discharge port.

2. The composite water jacket for a gradient-cooled multilayer metal blast furnace according to claim 1, characterized in that: The contact layer is made of corrosion-resistant metal material, the heat exchange layer is made of thermally conductive metal material, and the base layer is made of pressure-resistant metal material; the base layer is also provided with reinforcing ribs on the outside.

3. A gradient cooling multilayer metal blast furnace composite water jacket according to claim 1 or 2, characterized in that: The contact layer material is at least one of Hastelloy, 625 alloy and C276 alloy; the heat exchange layer is at least one of copper, oxygen-free copper, aluminum and silver; the base layer is structural steel.

4. The composite water jacket for a gradient-cooled multilayer metal blast furnace according to claim 1, characterized in that: The thickness of the contact layer is 5-10 mm; the thickness of the heat exchange layer is 70-90 mm; and the thickness of the base layer is 10-30 mm.

5. The composite water jacket for a gradient cooling multilayer metal blast furnace according to claim 1, characterized in that: The diameter of the serpentine cooling pipe is 40-60% of the thickness of the heat exchange layer; the ratio of the pipe spacing to its diameter is 2-8:

1.

6. The composite water jacket for a gradient-cooled multilayer metal blast furnace according to claim 1, characterized in that: The composite water jacket is a quadrangular prism; the length of the rectangular slag discharge port is 30-40% of the side length of the composite water jacket near the metallurgical melt, and the width is 30-40% of the width of the composite water jacket.

7. A method for preparing a composite water jacket for a gradient-cooled multilayer metal blast furnace according to any one of claims 1 to 6, characterized in that: A multi-layer metal composite plate is obtained by seamlessly welding the contact layer, heat exchange layer, and base layer. A serpentine cooling pipe is then machined from one side of the base layer into the heat exchange layer. The base layer is then completed using the same material as the base layer, leaving only the cooling pipe ports. Inlet and outlet water ports are set at the ports to form a multi-layer metal composite water jacket precursor. Reinforcing ribs are set in the base layer of the precursor, and after heat treatment, the product is obtained.

8. The method for preparing a gradient-cooled multilayer metal blast furnace composite water jacket according to claim 7, characterized in that: The seamless welding is one of gas shielded welding, explosive welding and cumulative lap welding; when the seamless welding is explosive welding, the process is as follows: after laying the three plates with the same length and width dimensions flat, the explosive is evenly spread on the outer surface of the contact layer and detonated through the end of the detonator or detonating cord.

9. The method for preparing a composite water jacket for a gradient-cooled multilayer metal blast furnace according to claim 8, characterized in that: The explosive is a low-detonation-velocity explosive, comprising the following components by mass percentage: 64-75% expanded ammonium nitrate, 3-4% diesel oil, 2-3% powdered emulsion explosive, and 15-30% salt; the explosive charge density is approximately 0.6-0.8 g / cm³, and the layer thickness is 50-70 mm; the base layer is completed by gas shielded welding.

10. The method for preparing a gradient-cooled multilayer metal blast furnace composite water jacket according to claim 7, characterized in that: The heat treatment conditions are as follows: under a protective atmosphere, the temperature is increased from room temperature to 650-760℃ at a rate of 1-10℃ / min, held for 0.5-1.5h, and then cooled to room temperature in the furnace.

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