Electrolytic aluminum anode structure based on cold spraying silver-nickel coating threaded steel claw connection and manufacturing method of electrolytic aluminum anode structure

Abstract

The invention provides an electrolytic aluminum anode structure based on cold spraying silver-nickel coating threaded steel claw connection. The electrolytic aluminum anode structure comprises a steel claw and an anode carbon block. The two ends of each steel claw tooth are provided with a first external thread and a second external thread correspondingly, and the claw teeth are installed below the cross beam through the first external threads. The anode carbon block is provided with carbon bowls corresponding to the claw teeth in number, and the claw teeth are connected with the carbon bowls through second external threads; and a silver-nickel coating formed by a cold spraying process is arranged on the surface of the second external thread. The invention further provides a manufacturing method of the electrolytic aluminum anode structure. The silver-nickel coating is arranged on the surface of the second external thread at the joint of the claw teeth and the carbon bowl, so that the contact area between the steel claw and the carbon bowl is increased, the conductivity of the thread joint is greatly improved, the iron-carbon voltage drop generated when current passes through is reduced, the electric energy loss in the electrolytic aluminum process is reduced, and the service life of the steel claw is prolonged. The defects of threaded connection in the aspects of stability and conductivity under the severe working condition of electrolytic aluminum are overcome, and wide popularization and application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic aluminum equipment, and in particular to an electrolytic aluminum anode structure based on cold-sprayed silver-nickel coated threaded steel claw connection, and also to a method for manufacturing the electrolytic aluminum anode structure. Background Art

[0002] In the electrolytic aluminum industry, the optimization of anode structure has always been the core breakthrough point for enterprises to achieve cost reduction, increase efficiency and enhance competitiveness. The traditional phosphorus pig iron casting and connection anode technology that was relied on in the past, although it guaranteed the stability of the anode assembly to a certain extent in the early days, as the industry moves towards refinement and efficiency, its disadvantages have gradually become a development shackle. The phosphorus pig iron casting and connection process is extremely cumbersome, and in actual production scenarios, once the anode needs to be repaired or replaced, the operation of the electrolytic cell must be suspended, and complex cell stop operations must be performed. The old casting connection parts must be removed and re-cast. This not only instantly cuts off the continuity of production, resulting in a sharp increase in the idle cost of equipment, but also causes irreversible damage to the lining of the electrolytic cell due to frequent start-stop, greatly pushing up the overall production cost. More importantly, phosphorus pig iron itself has a high resistivity. When used as a connecting medium for current transmission, a significant voltage drop is generated at the anode connection part, and a large amount of electrical energy is consumed unnecessarily in the form of heat energy, which seriously restricts the efficiency of electrolytic aluminum production and greatly weakens the economic benefits of the enterprise.

[0003] In order to break this dilemma, threaded connection technology came into being and gained attention from the industry. With its convenient operation and detachable characteristics, it effectively simplifies the anode assembly process and provides support for improving production efficiency. However, in-depth production practice found that this technology still has obvious shortcomings. The electrolysis workshop is full of harsh working conditions such as mechanical vibration, high temperature erosion and electrolyte corrosion. The threaded connection is in such a complex environment for a long time, which is prone to loosening and breaking, seriously threatening the stability of the anode structure and greatly shortening its service life. Frequent maintenance work has greatly reduced the results of previous efficiency improvements. At the same time, relying solely on the threaded structure, it is difficult to make a major breakthrough in optimizing the conductive performance, and it is impossible to fully meet the urgent needs of the electrolytic aluminum industry for efficient and low-consumption power transmission. A lot of energy-saving space needs to be explored.

[0004] Based on this, improving the structural stability and conductivity of the threaded connection parts of the electrolytic aluminum anode structure, improving the energy utilization efficiency in the electrolytic aluminum process, significantly extending the service life of the anode structure, and ensuring its long-term stable operation are of great significance for ensuring the continuity and stability of electrolytic aluminum production. It is also a technical problem that needs to be solved urgently. Summary of the invention

[0005] One of the purposes of the present invention is to provide an electrolytic aluminum anode structure with good structural stability, long service life and meeting the requirements of high-efficiency and low-power energy transmission in electrolytic aluminum production.

[0006] The second object of the present invention is to provide a method for manufacturing an electrolytic aluminum anode structure which has good structural stability, long service life and meets the requirements of high-efficiency and low-power energy transmission in electrolytic aluminum production.

[0007] The technical solution adopted by the present invention to achieve one of the purposes is: to provide an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws, including steel claws and anode carbon blocks; The steel claw comprises a crossbeam and a plurality of claw teeth; the two ends of the claw teeth are respectively provided with a first external thread and a second external thread, and the claw teeth are installed under the crossbeam through the first external thread; The anode carbon block is provided with a carbon bowl corresponding to the number of claws, and the claws are connected to the carbon bowl through a second external thread; the surface of the second external thread is provided with a silver-nickel coating formed by a cold spraying process; the silver-nickel coating has a thickness of 5-10mm and is composed of 80wt.%-90wt.% of Ag and 10wt.%-20wt.% of Ni.

[0008] The general idea of ​​the present invention is as follows: The electrolytic aluminum anode structure provided by the present invention uses a threaded connection to replace the conventional phosphorus pig iron casting solution, and uses cold spraying technology to set a certain thickness of silver-nickel coating on the surface of the second external thread of the claw and the carbon bowl threaded connection. As a cutting-edge new material surface strengthening process, cold spraying shows unique advantages compared to traditional thermal spraying: it can accurately drive silver-nickel alloy powder to impact the substrate surface at high speed under a relatively low temperature environment, so that silver-nickel atoms are closely arranged and interpenetrated, thereby forming a coating with a highly dense structure and super strong bonding with the substrate. The silver-nickel coating itself has multiple excellent properties: silver has excellent electrical conductivity, and the addition of nickel further optimizes the overall mechanical properties and chemical stability of the alloy. The synergistic effect of the two makes the silver-nickel coating have extremely low resistivity. When this silver-nickel coating formed by cold spraying is applied to the anode threaded connection part, it opens up a low-resistance transmission channel for the current, greatly reduces the loss of electric energy at the connection part, significantly improves the electric energy utilization efficiency in the electrolytic aluminum process, greatly extends the service life of the anode structure, ensures its long-term stable operation, and thus effectively guarantees the continuity and stability of electrolytic aluminum production.

[0009] Furthermore, the silver-nickel alloy powder used for cold spraying is composed of 80wt.%-90wt.% Ag and 10wt.%-20wt.% Ni. Among them, silver is an excellent conductive material, and its conductivity is far superior to other metals. In the silver-nickel alloy, the higher the silver content, the better the conductivity; but too high a silver content will significantly increase the cost of the alloy and will also have an adverse effect on the mechanical properties of the connection parts. At the same time, the addition of a certain proportion of nickel can significantly improve the corrosion resistance of the alloy. In the harsh environment of electrolytic aluminum, the anode assembly needs to withstand harsh conditions such as high temperature and strong corrosion. In combination with the requirements of the application environment of the silver-nickel coating, the present invention optimizes and adjusts the content of silver and nickel in the silver-nickel alloy composition, so that the anode maintains high conductivity while also having good mechanical properties, including hardness, wear resistance, etc., which can meet the requirements of the mechanical properties of the anode assembly during use. Preferably, the silver-nickel alloy powder adopts AgNi15 (85 wt.% Ag, 15wt.% Ni), and the particle size of the silver-nickel alloy powder is 20-30μm.

[0010] Furthermore, in the present invention, the thickness of the silver-nickel coating is set to 5-10mm. Studies have shown that when the thickness of the silver-nickel coating is less than 5mm, it is susceptible to mechanical wear, chemical corrosion or thermal stress, thereby reducing its service life. When the coating thickness exceeds a certain range, it will affect its bonding with the substrate. When the coating thickness exceeds 10mm, it is more likely to peel off or fall off under the harsh application conditions of electrolytic aluminum, thereby reducing the adhesion and durability of the coating. In addition, too thick a silver-nickel coating will also affect the close fitting connection between the claws and the charcoal bowl.

[0011] Furthermore, the crossbeam is provided with a mounting hole, and the first external thread of the claw passes through the mounting hole and is connected and fixed with the connecting nut above the crossbeam. The inner diameter of the mounting hole matches the diameter of the claw, and after the claw is installed and fixed, the part of the claw passing through the mounting hole is tightly fitted with the inner wall of the mounting hole.

[0012] Furthermore, a boss is provided on the top of the anode carbon block, and the carbon bowl is opened on the boss; and an internal thread matching the second external thread is provided on the inner wall of the carbon bowl.

[0013] Furthermore, the number of the claw teeth is 4-6.

[0014] Furthermore, the second external thread is a triangular thread with a thread angle of 50-60°. The thread angle refers to the angle between the two sides of the thread thread in the axial section of the thread. Preferably, the thread angle is 55°. Preferably, the height of the second external thread is 90-120mm, and the pitch is set to 6-8mm. The present invention adopts a wider pitch to adapt to the temperature change of the large-area steel claw in the electrolytic environment, reducing the risk of coating cracking caused by thermal expansion and contraction. At the same time, the wider pitch enables the powder to be more evenly distributed on the large-area thread surface during spraying, ensuring the coating quality. Preferably, the major diameter of the second external thread is 170-200mm, and the minor diameter of the second external thread is 165-185mm.

[0015] In the present invention, by optimizing the size structure of the second external thread, it can not only meet the support requirements of the overall structure of the anode for the steel claw, but also reserve sufficient space for the coating to avoid the accumulation of the coating affecting the performance of the steel claw. A triangular thread is used and the tooth angle is controlled at 50-60° to improve the connection strength and sealing performance of the second external thread and the internal thread of the carbon bowl.

[0016] The technical solution adopted by the present invention to achieve the second purpose is: to provide a method for manufacturing an electrolytic aluminum anode structure based on cold sprayed silver-nickel coated threaded steel claw connection according to one of the purposes of the present invention, comprising the following steps: S1, processing claw teeth with a first external thread and a second external thread; S2. Process the connecting nut according to the size of the claw teeth and open a carbon bowl with internal threads on the boss of the anode carbon block; S3, roughening and cleaning the surface of the second external thread of the claw, preheating the claw, and then preparing a silver-nickel coating on the surface of the second external thread by cold spraying; S4. Connect the lower end of each claw to the corresponding carbon bowl by thread, and then use the connecting nut to connect and fix the upper end of each claw to the crossbeam, thus completing the manufacture and assembly of the electrolytic aluminum anode structure.

[0017] In the above manufacturing method, claws with external threads at both ends and an internally threaded carbon bowl are first processed, and each claw is threadedly connected to the corresponding internally threaded carbon bowl, and then assembled through a crossbeam and connecting screws, and finally the overall assembly of the electrolytic cell anode is realized. Compared with the anode structure assembly method of casting molten phosphorus pig iron, the manufacturing method of the present invention not only meets the working requirements of the electrolytic cell anode, but also facilitates the electrolytic aluminum enterprise to replace the anode and maintain the electrolytic cell.

[0018] Furthermore, in step S1, the raw steel is cut into billets of required length using cutting equipment; the billets are turned, drilled, taper processed, etc. by lathes, milling machines, drilling machines and other processing equipment to finally form claws with first and second external threads at the upper and lower ends respectively.

[0019] Furthermore, in step S2, the size of the internal thread of the carbon bowl is reserved according to the thickness of the silver-nickel coating.

[0020] Furthermore, in step S3, the roughening treatment method includes but is not limited to sandblasting, shot blasting and other processes. Cleaning is carried out by combining laser cleaning with alcohol cleaning to remove thread processing residues at the lower end of the claw teeth.

[0021] Furthermore, in step S3, the claw teeth are preheated by spraying without powder feeding, and the preheating temperature is 150-300°C.

[0022] Furthermore, in step S3, the process parameters of cold spraying include: spraying pressure of 1-3Mpa, spraying temperature of 450-550℃, spraying distance of 10-30 mm, and spraying speed of 0.3-0.8 m / s. In the present invention, the cold spraying process is used as the preparation method of the silver-nickel coating. Compared with the traditional thermal spraying technology, it can significantly reduce the thermal stress, oxidation and phase change problems in the coating, thereby maintaining the original performance of the silver-nickel alloy and improving the overall quality and durability of the coating. The spraying pressure of the cold spraying is set to 1-3Mpa, and the silver-nickel coating obtained by high-pressure cold spraying is of better quality and higher powder utilization. The silver-nickel coating prepared by the present invention has the characteristics of low porosity, strong bonding force, high conductivity and good friction resistance, which is conducive to reducing the voltage drop when power is turned on and reducing the wear of the threaded steel claws during use.

[0023] Preferably, in step S3, before cold spraying, the surface of the second external thread is sandblasted; the sandblasting uses 80-120 mesh white corundum sand as the sandblasting medium, the sandblasting pressure is 0.5-0.7 Mpa, and the surface roughness Ra of the second external thread after sandblasting is 3.2-6.3 μm. In the present invention, sandblasting can improve the surface roughness of the second external thread, provide more mechanical anchor points for the silver-nickel coating, and improve the adhesion between the coating and the thread surface.

[0024] Among them, 80-120 mesh white corundum sand is used as the sandblasting medium. White corundum sand has the advantages of high hardness, strong wear resistance, stable chemical properties, etc. It can efficiently remove impurities on the surface of threaded steel claws during the sandblasting process. At the same time, it is not easy to break, which can ensure the consistency of the sandblasting effect. Compared with other sandblasting materials, such as quartz sand, white corundum sand will not introduce impurities such as silicon elements that may affect the quality of the coating, which is conducive to ensuring the purity of the silver-nickel coating. Controlling the sandblasting pressure can ensure that the surface roughness of the thread is in a suitable range, which helps to achieve uniform spraying of the coating. If the surface is too rough, the coating may accumulate too thickly in some parts, while insufficient coverage in other parts will affect the overall quality and performance of the coating; if the surface is too smooth, the bonding force between the coating and the substrate will be insufficient. The present invention controls the sandblasting pressure to 0.5-0.7 Mpa, and the surface roughness Ra of the second external thread after sandblasting is 3.2-6.3μm, which can make the coating better leveled and adhered during spraying, forming a uniform and continuous coating, thereby improving the protective effect and service life.

[0025] Preferably, during the sandblasting process, the sandblasting angle is 70-80° to ensure that the sandblasting effect evenly covers the thread surface to avoid partial unprocessed or over-processed conditions; the movement speed of the spray gun is controlled to 80 - 120 mm / s so that the sand particles can more fully act on the thread surface.

[0026] Preferably, in step S3, after cold spraying, the second external thread provided with a silver-nickel coating is laser polished; in the laser polishing, the laser wavelength is 1064 nm, the pulse width is 10-30 ns, the laser power is 20-50 W, and the scanning speed is 5-15 mm / s. Laser polishing utilizes a high-energy-density laser beam to irradiate the surface of the silver-nickel coating, causing the surface material to melt and solidify rapidly, and fills microscopic pits and eliminates protrusions through the flow of the molten layer, thereby achieving the effect of smoothing the surface. In the present invention, for the cold-sprayed silver-nickel coating on the second external thread, the laser energy can act precisely on the atomic level of the coating, causing the coating to be redistributed, thereby achieving an improvement in the surface roughness after cold spraying, and thereby increasing its bonding strength with the carbon bowl.

[0027] Among them, a 1064nm wavelength laser is selected. This wavelength has a good absorption effect on metal materials and can efficiently transfer energy to the coating; the pulse width is controlled to be 10-30ns, so that the energy can be concentrated in a short time, the melting depth can be accurately controlled, and damage to the underlying steel claw matrix can be prevented. The present invention sets the laser power at 20-50W according to the size of the second outer screw and the degree of surface unevenness to ensure that the composition and performance of the coating are not changed while effectively polishing. If the laser power is too low, the polishing effect will be affected, and if the power is too high, the coating will be thermally damaged, resulting in defects such as burn marks and melting pits on the coating surface.

[0028] In the present invention, a combination of "sandblasting + cold spraying + laser polishing" is used to process the silver-nickel coating on the surface of the first external thread, so as to improve the adhesion, uniformity and flatness of the silver-nickel coating, ensure the stable connection between the steel claw and the carbon bowl, and play the role of a low-resistance transmission channel, reduce the loss of electric energy at the connection part, extend the service life of the anode structure, and ensure its long-term stable operation.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The present invention aims at the defects of structural stability and electrical conductivity of the threaded connection between the steel claw and the anode carbon block, focuses on the excellent characteristics of cold spraying technology and silver-nickel coating, and innovatively constructs an electrolytic aluminum anode structure and a manufacturing method thereof based on a cold-sprayed silver-nickel coating threaded steel claw connection. The present invention adopts a cold spraying process to prepare a silver-nickel coating on the surface of the second external thread at the lower end of the claw, which greatly increases the electrical conductivity, wear resistance and corrosion resistance of the claw, further reduces the iron-carbon pressure drop, reduces power loss, and plays a significant role in energy saving and efficiency improvement in the electrolytic aluminum process. Good electrical conductivity can ensure the stable transmission of current between the anode and the steel claw, reduce problems such as local overheating caused by excessive resistance, and is conducive to maintaining the stable operation state of the electrolytic cell. The silver-nickel coating can also provide effective protection for the threaded steel claw, resist the erosion of corrosive substances in the electrolyte, extend the service life of the threaded steel claw, and reduce the frequent replacement and maintenance costs caused by corrosion. At the same time, the presence of the coating can make the threaded connection more compact and reliable, and the coating can fill the tiny gaps between the threads, improve the sealing and mechanical strength of the connection, and reduce the risk of gap pressure drop and loosening. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the three-dimensional structure of an electrolytic aluminum anode structure connected by cold-sprayed silver-nickel coated threaded steel claws provided in an embodiment of the present invention; Figure 2 A front view of the cross-sectional structure of an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws provided in an embodiment of the present invention; Figure 3 A cross-sectional structural side view of an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws provided in an embodiment of the present invention; Figure 4 A schematic diagram of the structure of steel claw teeth in an electrolytic aluminum anode structure provided by an embodiment of the present invention; Among them, 1-crossbeam; 2-claw teeth; 21-first external thread; 22-second external thread; 23-silver-nickel coating; 3-carbon bowl; 4-connecting nut. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0033] like Figure 1-4 As shown, an embodiment of the present invention provides an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws, including steel claws and anode carbon blocks.

[0034] The steel claw includes a crossbeam 1 and four claw teeth 2 located below the crossbeam; the two ends of the claw teeth 2 are respectively provided with a first external thread 21 and a second external thread 22; the crossbeam 1 is provided with a mounting hole, and the first external thread 21 of the claw teeth 2 passes through the mounting hole and is connected and fixed to the connecting nut 4 above the crossbeam 1, so that the claw teeth 2 are installed below the crossbeam 1.

[0035] A boss is provided on the top of the anode carbon block, and a carbon bowl 3 corresponding to the number of claw teeth 2 is opened on the boss; the inner wall of the carbon bowl 3 is provided with an internal thread matching the second external thread 22, and the claw teeth 2 are connected to the carbon bowl 3 through the second external thread 22, thereby realizing the connection between the steel claw and the anode carbon block.

[0036] Furthermore, if Figure 4 As shown, the second external thread 22 is a triangular thread with a tooth angle of 55°, and the surface of the second external thread 22 is provided with a silver-nickel coating 23 formed by a cold spraying process; the silver-nickel coating 13 has a thickness of 5-10 mm and is composed of 80wt.%-90wt.% of Ag and 10wt.%-20wt.% of Ni.

[0037] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0038] Example 1 This embodiment provides an electrolytic aluminum anode structure based on cold-sprayed silver-nickel coated threaded steel claw connection, and the manufacturing method of the electrolytic aluminum anode structure includes the following steps: Step 1: Component machining 1: Use cutting equipment to cut the raw steel into billets of the required length; use lathes, milling machines, drilling machines and other processing equipment to turn, drill, taper, etc. on the billets, and finally form steel claw teeth 2 with threaded ends at both ends. Among them, the second external thread 22 of the steel claw teeth 2 has a height of 120mm, a pitch of 8mm, a major diameter of 200mm, a minor diameter of 185mm, and a tooth angle of 55°.

[0039] Step 2: Component machining 2: According to the size of the claw teeth 2, process the connecting nut 4 and open a carbon bowl 3 with internal threads on the boss of the anode carbon block; the size of the internal thread of the carbon bowl 3 reserves the thickness of the cold sprayed silver-nickel coating 9 to facilitate threaded connection with the sprayed steel claw teeth 2.

[0040] Step 3: roughen and clean the surface of the second external thread 22 of the claw 2, preheat the claw 2, and then prepare a silver-nickel coating 23 on the surface of the second external thread 22 by cold spraying, and finally perform laser polishing on the silver-nickel coating 23. Specifically: Step 301: sandblasting the second external thread of the claw: 100 mesh white corundum sand is used as the sandblasting medium, the sandblasting pressure is set to 0.6MPa, the sandblasting angle is controlled at 70°-80°, the moving speed is set to 100mm / s, and the surface of the second external thread of the claw is sandblasted, and the average surface roughness after treatment reaches 6.1μm; Step 302: Cold spraying silver-nickel coating: laser cleaning combined with alcohol cleaning is used to remove the thread processing residues at the lower end of the claw 3; the claw 3 is preheated by non-powder spraying; cold spraying technology is used, and AgNi15 (85% Ag, 15% Ni) with a particle size of 20 μm is used as the spraying powder under the conditions of spraying pressure of 2 MPa, spraying temperature of 550°C, spraying distance of 10 mm, and spraying speed of 0.3 m / s to prepare a silver-nickel coating 23 on the surface of the claw substrate, and the coating thickness is controlled to be 5 mm.

[0041] Step 303: Laser polishing of the silver-nickel coating surface: The threaded claw surface after cold spraying is laser polished, using a 1064nm wavelength laser, a pulse width of 20ns, a laser power of 40W, and a scanning speed of 10mm / s.

[0042] Step 4: Assemble the anode structure as a whole: thread the lower end of each claw 2 with the corresponding internal thread of the carbon bowl 3 through the second external thread 22. After each claw 2 is connected to the carbon bowl 3, use the connecting nut 4 to connect and fix the upper end of each claw 2 to the crossbeam 1 to realize the structural series connection, thus completing the manufacture and assembly of the electrolytic aluminum anode structure.

[0043] The electrolytic aluminum anode structure based on the cold sprayed silver-nickel coated threaded steel claw connection prepared in this embodiment is as follows: Figure 1-3 As shown, the components can be assembled and disassembled. The upper and lower ends of the claw teeth 2 of the steel claw are respectively provided with a first external thread 21 and a second external thread 22. The claw teeth 2 of the steel claw are connected to the carbon bowl 3 through the second external thread 22, thereby realizing the connection between the steel claw and the anode carbon block. Figure 4 As shown, the second external thread surface is provided with a silver-nickel coating 23 prepared by a cold spraying process.

[0044] In this embodiment, the setting of the silver-nickel coating 23 can, on the one hand, increase the conductivity of the claw teeth 2, reduce the iron-carbon pressure drop, and reduce power loss, which plays a significant role in energy saving and efficiency improvement in the electrolytic aluminum process; on the other hand, the silver-nickel coating 23 can make the threaded connection tighter and more reliable. The coating can fill the tiny gaps between the threads, improve the sealing and mechanical strength of the connection, and reduce the risk of gap pressure drop and loosening. In addition, the silver-nickel coating 23 can also improve the wear resistance and corrosion resistance of the claw teeth, provide effective protection for the threaded steel claws, resist the erosion of corrosive substances in the electrolyte, extend the service life of the threaded steel claws, and reduce the frequent replacement and maintenance costs caused by corrosion.

[0045] Example 2 This embodiment provides an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws. The difference from Embodiment 1 is that the steel claw is provided with 6 claw teeth, and 6 carbon bowls are provided at the anode carbon block boss, which correspond one-to-one to the claw teeth of the anode steel claws.

[0046] Example 3 This embodiment provides an electrolytic aluminum anode structure connected based on cold-sprayed silver-nickel coated threaded steel claws. The difference from Embodiment 1 is that the second external thread 22 of the claw 2 has a height of 90 mm, a pitch of 6 mm, a major diameter of 170 mm, a minor diameter of 165 mm, and a tooth angle of 55°.

[0047] Embodiment 4: This embodiment provides an electrolytic aluminum anode structure connected by cold-sprayed silver-nickel coated threaded steel claws. The difference from Embodiment 1 is that in step 302 of the manufacturing method, the parameters of cold spraying are as follows: the spraying pressure is 1 MPa, the spraying temperature is 450°C, the spraying distance is 30 mm, the spraying speed is 0.8 m / s, and AgNi15 (85% Ag, 15% Ni) with a particle size of 30 μm is used as the spraying powder to prepare a silver-nickel coating 23 on the surface of the claw substrate, and the coating thickness is controlled to be 10 mm.

[0048] Example 5 This embodiment provides an electrolytic aluminum anode structure connected by cold-sprayed silver-nickel coated threaded steel claws. The difference from Embodiment 1 is that in step 301 of the manufacturing method, 90 mesh white corundum sand is used as the sandblasting medium for sandblasting, the sandblasting pressure is set to 0.7 MPa, the sandblasting angle is controlled at 70°-80°, the moving speed is set to 80 mm / s, and the surface of the threaded claw teeth is sandblasted. The average surface roughness after treatment reaches 5.5 μm.

[0049] Example 6 This embodiment provides an electrolytic aluminum anode structure connected based on a cold-sprayed silver-nickel coated threaded steel claw. The difference from Embodiment 1 is that in step 303 of the manufacturing method, the surface of the threaded claw teeth after cold spraying is laser polished, and a 1064nm wavelength laser is selected, with a pulse width of 10ns, a laser power of 50W, and a scanning speed of 15mm / s.

[0050] Comparative Example 1 The difference between this comparative example and Example 1 is that the traditional phosphorus pig iron casting method is used to achieve the anode structure connection, and only the sandblasting-cold spraying-laser polishing process similar to step 3 of Example 1 is performed on the surface of the cylindrical steel claw teeth. The dimensions of the claw teeth connected to the phosphorus pig iron are: 200 mm in diameter and 130 mm in height.

[0051] Comparative Example 2 The difference between this comparative example and Example 1 is that the traditional phosphorus pig iron casting method is used to achieve the anode structure connection, and only the sandblasting-cold spraying-laser polishing process similar to step 3 of Example 1 is performed on the surface of the cylindrical steel claw teeth, and the dimensions of the claw teeth connected to the phosphorus pig iron are: diameter 170 mm, height 90 mm.

[0052] Comparative Example 3 The difference between this comparative example and Example 1 is that the manufacturing method does not include the sandblasting-cold spraying-laser polishing process of step 3, and only designs and manufactures an electrolytic aluminum anode structure in which the steel claw is threadedly connected to the anode carbon block.

[0053] Pressure drop comparison The steel claw was polished 10 cm away from the mouth of the bowl to remove the oxide film and then connected to one pole of a voltage-stabilized power supply. The carbon bowl was connected to the other pole of the voltage-stabilized power supply 10 cm away from the mouth of the bowl and connected to a precision millivoltmeter. The voltage drop of the anode assemblies for electrolytic aluminum prepared in Examples 1, 3-6 and Comparative Examples 1-3 was tested and calculated. The results are shown in Table 1 below.

[0054] Table 1

[0055] As can be seen from the above table, On the premise that the claw structure and size data of the steel claw are consistent, compared with the comparative example, the embodiment of the present invention adopts a combination of a second external thread and a silver-nickel coating at the connection between the claw and the carbon bowl, making the threaded connection more compact and reliable. The silver-nickel coating fills the tiny gap between the second external thread and the internal thread of the carbon bowl, improving the sealing and mechanical strength of the connection, and reducing the risk of gap pressure drop and loosening. In addition, the setting of the silver-nickel coating also improves the electrical conductivity, reduces the iron-carbon pressure drop, and reduces the power loss, which can play a role in energy saving and efficiency improvement in the electrolytic aluminum process.

[0056] It should be noted that in the manufacturing method of the anode structure provided by the present invention, the component machining processing of steps 1 and 2 and the cold spraying of step 3 can be outsourced to professional enterprise factories for mass production. In the actual operation process, the relevant process parameters of machining and cold spraying can be tested and adjusted according to the specific equipment conditions of the OEM factory to ensure high-quality spiral claw tooth components and silver-nickel coatings.

[0057] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrolytic aluminum anode structure based on cold sprayed silver-nickel coated threaded steel claw connection, characterized in that: Includes steel claws and anode carbon blocks; The steel claw comprises a crossbeam (1) and a plurality of claw teeth (2); the two ends of the claw teeth (2) are respectively provided with a first external thread (21) and a second external thread (22); the claw teeth (2) are installed below the crossbeam (1) via the first external thread (21); The anode carbon block is provided with a carbon bowl (3) corresponding to the number of claws (2), and the claws (2) are connected to the carbon bowl (3) via a second external thread (22); the surface of the second external thread (22) is provided with a silver-nickel coating (23) formed by a cold spraying process; the silver-nickel coating (13) has a thickness of 5-10 mm and is composed of 80wt.%-90wt.% of Ag and 10wt.%-20wt.% of Ni.

2. The electrolytic aluminum anode structure according to claim 1, characterized in that: The crossbeam (1) is provided with a mounting hole, and the first external thread (21) of the claw (2) passes through the mounting hole and is connected and fixed to a connecting nut (4) above the crossbeam (1).

3. The electrolytic aluminum anode structure according to claim 1, characterized in that: A boss is provided on the top of the anode carbon block, and the carbon bowl (3) is opened on the boss; an internal thread matching the second external thread (22) is provided on the inner wall of the carbon bowl (3).

4. The electrolytic aluminum anode structure according to claim 1, characterized in that: The number of the claw teeth (2) is 4-6.

5. The electrolytic aluminum anode structure according to claim 1, characterized in that: The second external thread (22) is a triangular thread with a thread angle of 50-60°.

6. A method for manufacturing an electrolytic aluminum anode structure based on cold-sprayed silver-nickel coated threaded steel claw connection according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, machining a claw tooth (2) with a first external thread (21) and a second external thread (22); S2. According to the size of the claw teeth (2), a connecting nut (4) is processed and a carbon bowl (3) with an internal thread is opened on the boss of the anode carbon block; S3, roughening and cleaning the surface of the second external thread (22) of the claw (2), preheating the claw (2), and then preparing a silver-nickel coating (23) on the surface of the second external thread (22) by cold spraying; S4. The lower end of each claw (2) is threadedly connected to the corresponding carbon bowl (3), and then the upper end of each claw (2) is connected and fixed to the crossbeam (1) using a connecting nut (4), thereby completing the manufacture and assembly of the electrolytic aluminum anode structure.

7. The manufacturing method according to claim 6, characterized in that: In step S2, the size of the internal thread of the carbon bowl (3) is reserved according to the thickness of the silver-nickel coating (23).

8. The manufacturing method according to claim 6, characterized in that: In step S3, the process parameters of cold spraying include: spraying pressure of 1-3 MPa, spraying temperature of 450-550° C., spraying distance of 10-30 mm, and spraying speed of 0.3-0.8 m / s.

9. The manufacturing method according to claim 8, characterized in that In step S3, before cold spraying, the surface of the second external thread (22) is sandblasted; the sandblasting uses 80-120 mesh white corundum sand as the sandblasting medium, the sandblasting pressure is 0.5-0.7 Mpa, and the surface roughness Ra of the second external thread (22) after the sandblasting is 3.2-6.3 μm.

10. The manufacturing method according to claim 8, characterized in that In step S3, after cold spraying, the second external thread (22) provided with the silver-nickel coating is laser polished; in the laser polishing, the laser wavelength is 1064 nm, the pulse width is 10-30 ns, the laser power is 20-50 W, and the scanning speed is 5-15 mm / s.

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