Long-life energy-saving anode conductive device for aluminum electrolysis

Abstract

The present application discloses a long-life energy-saving anode conductive device for aluminum electrolysis. The anode conductive device comprises an anode guide rod, an aluminum-titanium steel explosion welding block with reinforcing ribs, and an anode steel claw. The surface of the aluminum-titanium steel explosion welding block is stacked with an aluminum layer, a titanium layer, and a steel layer from the inside to the outside, the reinforcing ribs are fixedly connected to the aluminum layer of the aluminum-titanium steel explosion welding block, the lower end face of the anode guide rod is welded to the aluminum layer of the aluminum-titanium steel explosion welding block through an aluminum-aluminum lap weld, and the upper end face of the anode steel claw is welded to the steel layer of the aluminum-titanium steel explosion welding block through a steel-steel butt weld. In this technical solution, the brittle phase generated by welding of dissimilar materials of aluminum and steel is avoided; the reinforcing ribs are fixed relative to the explosion welding block to avoid thermal strain generated during welding; and a high entropy alloy coating is prepared on the surface of the steel claw leg to improve corrosion resistance. According to the test of the embodiment, the voltage drop is reduced by more than half during conduction. The present invention has the characteristics of low voltage drop, high connection strength, good corrosion resistance, long service life, etc., and has obvious economic and social benefits.

Description

Technical Field

[0001] The present application relates to the technical field of nonferrous metal metallurgy, and in particular to a long-life energy-saving anode conductive device for aluminum electrolysis. Background Art

[0002] In the electrolytic aluminum industry, the anode conductive device is composed of an anode aluminum guide rod and an anode steel claw. In industrial applications, the anode device is in a high-temperature and highly corrosive working environment. It must not only conduct large currents, but also withstand the gravity load of steel claws and carbon blocks. Therefore, the performance requirements of the aluminum-steel connection joint are extremely high. Aluminum-steel dissimilar material welding joints are prone to produce brittle intermetallic compounds, which greatly reduces the connection strength of the joint, shortens the service life of the anode steel claw, and increases the production investment of the enterprise. The existing technology is to weld the aluminum-steel explosion welding block to the aluminum guide rod and the anode steel claw along the contact area, which can effectively avoid the generation of brittle intermetallic compounds during aluminum-steel welding. However, the expansion coefficients of aluminum and steel are quite different. Under the action of high temperature and high current during operation, large shear stress and tensile stress are generated at the joint of the composite welding block, resulting in partial or complete cracking of the welding surface, reduced conductive area, increased resistance, and further aggravated The fracture trend at the joint.

[0003] Secondly, at the working temperature of 350-900℃, the interaction of electrolytic flue gas, air, thermal stress, electromagnetic force, etc. can easily lead to corrosion of the anode steel claws, forming a "thin waist" phenomenon, thus shortening the service life of the anode steel claws. At present, the anode steel claw protection ring is the main anti-corrosion method used by aluminum electrolysis plants. The anode steel claw protection ring method can effectively separate the steel claws from the covering material, but it has poor oxidation and corrosion resistance, and requires multiple processes such as stirring, molding, demoulding, roasting, and cooling. The processing technology is complicated, which is not conducive to reducing the production cost of the enterprise.

[0004] Patent CN109518229A invented a method of connecting anode guide rod and steel claw by friction welding. Although the service life is greatly improved, the aluminum-steel joint obtained by friction welding will shorten the anode guide rod due to friction during the maintenance or replacement process, which is not conducive to the recycling and reuse of the anode guide rod. At the same time, the friction welding equipment is expensive, the production cost of the enterprise is too high, and it is difficult to promote in the industry. Patent CN110257860A discloses a composite-molded anode conductive device and its manufacturing method, which is characterized by connecting four composite components to form a rectangular frame, the outer side of the rectangular frame is an aluminum-based plate, and the inner side is a steel-based plate. The connection between the steel claw and the guide rod is achieved by welding the same material. Although this method improves the problem of hard and brittle bonding surface, the weld cross section generates internal torque under the high gravity of the anode steel claw and carbon block, which is very easy to tear from the root of the weld and cause the claw to fall off. At the same time, this method changes the composite parts from the traditional horizontal placement to the vertical placement. When welding on the aluminum side, the constraints are too small. In the actual production process, due to the high expansion coefficient of aluminum, it will produce a warping tendency under the large welding heat input, and generate thermal stress at the joint surface of the aluminum plate and the steel plate, thereby reducing the strength of the composite parts. When welding the steel plate and the anode steel claw with the steel inside, the narrow and deep groove will cause construction difficulties, making it difficult to improve the production efficiency of the factory.

[0005] Patent CN204474771U invented an anode steel claw protection ring, which uses left and right half rings made of graphite material to form a protection ring. This method can isolate the steel claw and the covering material. The sealing of the fitting part is poor, and the steel claw will still be corroded by oxidation. Patent CN202246917U invented an aluminum electrolytic cell anode steel claw metal protection ring. The protection ring material is heat-resistant cast steel or hot cast iron with strong resistance to electrolyte corrosion. It has the advantages of little pollution to the covering material and can be reused, but the protection ring is complicated to process and has high material cost. Summary of the invention

[0006] In view of this, the present application provides a long-life energy-saving anode conductive device for aluminum electrolysis, which has high strength, low voltage drop and corrosion resistance.

[0007] The present application provides a long-life energy-saving anode conductive device for aluminum electrolysis, comprising an anode guide rod, an aluminum-titanium steel explosion welding block with reinforcing ribs, and an anode steel claw, wherein the surface of the aluminum-titanium steel explosion welding block is sequentially stacked with an aluminum layer, a titanium layer, and a steel layer from the inside to the outside, the reinforcing ribs are fixedly connected to the aluminum layer of the aluminum-titanium steel explosion welding block, the lower end face of the anode guide rod is welded to the aluminum layer of the aluminum-titanium steel explosion welding block by an aluminum-aluminum lap weld, and the upper end face of the anode steel claw is welded to the steel layer of the aluminum-titanium steel explosion welding block by a steel-steel butt weld.

[0008] Optionally, the thickness of the titanium layer is 0-3 mm, the thickness of the aluminum layer is 8-20 mm, and the thickness of the steel layer is 30-50 mm;

[0009] Preferably, the height of the aluminum-titanium steel explosion welding block is not less than 120 mm.

[0010] Optionally, the aluminum layer is provided with screw holes, and the reinforcing ribs are ceramic tubes with threads at both ends.

[0011] Optionally, the aluminum-titanium steel explosion welding block is composed of four aluminum-titanium steel explosion units, wherein the aluminum-titanium steel explosion units in relative positions among the four aluminum-titanium steel explosion units are fixed by reinforcing ribs, and adjacent aluminum-titanium steel explosion units are welded by corner joints.

[0012] Optionally, the distance between the lower end surface of the anode guide rod and the anode steel claw is 5-300 mm.

[0013] Optionally, the aluminum layer and the anode guide rod are welded by MIG or TIG argon arc welding, the welding material is aluminum or aluminum silicon welding wire, the welding wire diameter is 2.0 mm, and the welding current is 120-180A.

[0014] Optionally, the steel layer and the anode steel claw are welded by manual arc welding, gas shielded welding or submerged arc welding, and the welding materials are J422, J507 welding rods or H08 welding wires, and the diameters of the welding rods and welding wires are 3.2 mm and 1.2 mm respectively.

[0015] Optionally, the aluminum-titanium steel explosion welding block is welded with the anode guide rod and the anode steel claw in a full welding manner.

[0016] Optionally, a high entropy alloy layer is clad on the side of the steel claw leg of the anode steel claw;

[0017] Preferably, a layer of high entropy alloy is clad on the surface of the steel-steel butt weld.

[0018] Optionally, the high entropy alloy layer is composed of Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 .

[0019] Compared with the related art, the beneficial effects of this application are:

[0020] (1) The present application adopts an aluminum-titanium steel explosion welding block frame with reinforcing ribs as a component for connecting the anode guide rod and the anode steel claw. The structure is novel and unique. Compared with the use of aluminum-steel explosion welding blocks, this method has the advantages of high temperature resistance, low pressure drop, and high tensile strength. According to test measurements, the pressure drop during conduction is reduced by more than half, achieving energy saving and emission reduction.

[0021] (2) The present application uses an aluminum-titanium steel explosion welding block frame with reinforcing ribs as a component for connecting the anode guide rod and the anode steel claw, wherein the aluminum located on the inner side can be connected to the guide rod through two welds, greatly improving the joint strength and the conductive area of ​​the joint.

[0022] (3) The present application uses an aluminum-titanium steel explosive welding block frame with reinforcing ribs as a component for connecting the anode guide rod and the anode steel claw, wherein the steel is located on the outside and welded to the steel claw, thereby avoiding the opening of the welding groove and significantly limiting the welding deformation of the inner aluminum layer.

[0023] (4) The present application adopts an aluminum-titanium steel explosion welding block as a welding frame, and the bonding strength of the dissimilar metal interface is increased from about 150 MPa of the aluminum-steel explosion block to about 200 MPa.

[0024] (5) The present application uses an aluminum-titanium steel explosion welding block frame with reinforcing ribs as a component for connecting the anode guide rod and the anode steel claw, and twelve welds are used on four sides to further significantly improve the overall strength of the welded joint.

[0025] (6) The present application uses ceramic tubes as reinforcing ribs. When welding at both ends of the explosive welding block, the ceramic tubes have extremely high elastic modulus. At the same time, the outer side of the explosive welding block frame is a steel plate with high thermal melting point and low expansion coefficient. Under the constraints of the two, the thermal strain generated by heat input during aluminum welding is effectively reduced, thereby reducing the internal stress of the explosive welding block frame, greatly improving the reliability of the connection between the anode guide rod and the anode steel claw, and avoiding the occurrence of claw drop accidents. The ceramic tubes with excellent properties such as wear resistance, corrosion resistance, and high temperature resistance will not be corroded by high temperature and electrolytic fume when the device is actually working, and the structure is stable. At the same time, their extremely high resistivity and dielectric strength enable them to withstand high voltages and reduce leakage losses, thereby avoiding the occurrence of uneven current when the device is conducting.

[0026] (7) The present application uses a Mo-containing high entropy alloy coating to improve the corrosion resistance of the anode steel claw. FeCoCrNi alloy has excellent corrosion resistance, ductility and structural stability. Mo element has good oxidation resistance. Adding a certain amount of Mo element forms an ordered σ strengthening phase in the coating to produce precipitation strengthening. In addition, the atomic size of Mo element is much larger than that of the other four elements, and dislocation strengthening caused by the difference in atomic size will occur inside the coating. Under the combined effect of the two strengthening effects, the hardness and corrosion resistance of the coating are further improved.

[0027] (8) Compared with the method of using anode steel claw protection ring, high entropy alloy coating has the advantages of simple processing technology, strong bonding, and stronger corrosion resistance. It can effectively extend the service life of the anode steel claw. At the same time, it eliminates multiple production processes such as stirring, molding, demolding, roasting, and cooling. The cladding technology can be used for one-time molding on the surface, saving a lot of labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0029] Figure 1 This is a front view of the anode conductive device in this application;

[0030] Figure 2 A top view of the aluminum-titanium steel explosion welding block frame in this application;

[0031] Figure 3 It is the aluminum-titanium steel explosion welding block A plate in this application;

[0032] Figure 4 It is the aluminum-titanium steel explosion welding block B plate in this application;

[0033] Figure 5 This is a microstructure photo of the junction between the anti-corrosion coating and the substrate in this application;

[0034] Figure 6 This is a microstructure photo of the anti-corrosion coating in this application;

[0035] Figure 7 This is the hardness curve of the anti-corrosion coating in this application.

[0036] In the figure:

[0037] 1. Anode guide rod; 2. Aluminum-titanium-steel explosion welding block; 2-1. Aluminum layer; 2-2. Titanium layer; 2-3. Steel layer; 3. Upper boss; 4. Anode steel claw; 5. High entropy alloy coating; 6. Steel claw leg; 7. Aluminum-aluminum lap weld; 7-1. Aluminum-aluminum outer lap weld; 7-2. Aluminum inner lap weld; 8. Steel-steel butt weld; 9. Aluminum-aluminum fillet weld; 10. Reinforcement ribs; 11. Aluminum layer of plate A; 12. Screw holes; 13. Aluminum layer of plate B. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0039] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0042] Example 1

[0043] refer to Figure 1-Figure 7 The manufacturing method of the long-life energy-saving anode conductive device for aluminum electrolysis in this example comprises the following steps:

[0044] Step 1: The explosive welding block is divided into an A plate aluminum layer 11 and a B plate aluminum layer 13. The A plate aluminum layer 11 is provided with a screw hole 12 on the upper part, and the B plate aluminum layer 13 is provided with a screw hole 12 on the lower part. The four explosive welding block units form a rectangular frame, the inner side is an aluminum layer 2-1, the middle layer is a titanium layer 2-2, and the outer side of the titanium layer 2-2 is a steel layer 2-3. The welding blocks in the same group are placed opposite to each other and fixed by two reinforcing ribs 10 (such as ceramic tubes) with threads at the ends. Two adjacent explosive welding block units are fixed by an aluminum-aluminum fillet weld 9, and the welding joint type is a fillet joint.

[0045] Step 2: After grinding the lower end of the anode guide rod 1, insert it into the aluminum-titanium steel explosion welding block 2. The side surface of the anode guide rod 1 contacts the aluminum layer 2-1 of the aluminum-titanium steel explosion welding block 2, that is, it is fixed by two aluminum-aluminum lap welds 7. The two aluminum-aluminum lap welds 7 include an aluminum-aluminum outer lap weld 7-1 and an aluminum-aluminum inner lap weld 7-2. MIG welding is used, the welding material is aluminum welding wire, the welding wire diameter is 2.0 mm, and the welding current is 130A;

[0046] Step 3: placing the aluminum-titanium steel explosion welding block 2 on the upper boss 3, and providing a groove at the steel-steel joint, that is, welding and fixing it through the steel-steel butt weld 8, using manual arc welding, the welding material is J422 welding rod, and the welding rod diameter is 3.2 mm;

[0047] Step 4: After grinding the side of the steel claw leg 6 of the anode steel claw 4, plasma cladding is performed on the surface to prepare Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 High entropy alloy coating5.

[0048] Step 5: Grind the surface of the steel-steel butt weld 8 and then perform plasma cladding to prepare Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 High entropy alloy coating.

[0049] The anode conductive device provided in this embodiment uses an aluminum-titanium steel explosion welding block 2 with a reinforcing rib 10 as a connecting component, which has the advantages of low pressure drop and high strength. Through testing under actual industrial working conditions, the pressure drop during operation is reduced by 52% and the temperature of the connecting part is reduced by 27°C.

[0050] Depend on Figure 5 It can be observed that the aluminum-titanium-steel joint surface forms a regular wavy interface after explosion welding. The macroscopic combination is tight and no obvious intermediate layer can be seen. The vortex-shaped cast structure can be seen at the peaks and troughs. The wavy interface can effectively increase the bonding area between titanium and steel and between titanium and aluminum, effectively prevent the generation of cracks, and improve the mechanical properties of the composite material. In addition, by observing the plasma cladding high entropy alloy coating ( Figure 7 ) It can be seen that the coating as a whole presents a typical dendrite structure, and the dendrite growth has a certain orientation, and its growth direction is perpendicular to the substrate. Figure 6 It can be found that the coating and the substrate material are closely combined. When the coating and the substrate are corroded by the highly corrosive aqua regia, the grain boundary of the coating is lighter in color, while the grain boundary of the steel substrate is darker in color, indicating that the corrosion resistance of the coating is significantly higher than that of the substrate material. Figure 7) It can be seen that the average hardness of the coating is 371.3HV, and the average hardness of the steel substrate is 204.3HV. The hardness of the coating is 81.74% higher than that of the substrate.

[0051] Example 2

[0052] refer to Figure 1-Figure 7 The manufacturing method of the long-life energy-saving anode conductive device for aluminum electrolysis in this example comprises the following steps:

[0053] Step 1: The explosive welding block is divided into an A plate aluminum layer 11 and a B plate aluminum layer 13, a screw hole 12 is provided on the upper part of the A plate aluminum layer 11, and a screw hole 12 is provided on the lower part of the B plate aluminum layer 13. Four explosive welding block units form a rectangular frame, the inner side is an aluminum layer 2-1, the middle layer is a titanium layer 2-2, and the outer side of the titanium layer 2-2 is a steel layer 2-3. The welding blocks of the same group are placed opposite to each other and fixed by two reinforcing ribs 10 (such as ceramic tubes) with threads at the ends. Two adjacent explosive welding block units are fixed by aluminum-aluminum fillet welds 9, and the welding joint type is a fillet joint;

[0054] Step 2: After grinding the lower end of the anode guide rod 1, insert it into the aluminum-titanium steel explosion welding block 2. The side surface of the anode guide rod 1 contacts the aluminum layer 2-1 of the aluminum-titanium steel explosion welding block 2, that is, it is fixed by two aluminum-aluminum lap welds 7. The two aluminum-aluminum lap welds 7 include an aluminum-aluminum outer lap weld 7-1 and an aluminum inner lap weld 7-2. TIG welding is used, the welding material is aluminum-silicon welding wire, the welding wire diameter is 2.0 mm, and the welding current is 160A;

[0055] Step 3: placing the aluminum-titanium steel explosion welding block 2 on the upper boss 3, and providing a groove at the steel-steel joint, that is, welding and fixing it through the steel-steel butt weld 8, using submerged arc welding, the welding material is H08 welding wire, and the welding wire diameter is 1.2 mm;

[0056] Step 4: After grinding the steel claw leg 6 of the anode steel claw 4, plasma cladding is performed on the surface to prepare Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 High entropy alloy coating5.

[0057] Step 5: Grind the surface of the steel-steel butt weld 8 and then perform plasma cladding to prepare Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 High entropy alloy coating.

[0058] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A long-life energy-saving anode conductive device for aluminum electrolysis, characterized in that: It comprises an anode guide rod (1), an aluminum-titanium steel explosion welding block (2) with a reinforcing rib (10), and an anode steel claw (3), wherein the surface of the aluminum-titanium steel explosion welding block is sequentially stacked with an aluminum layer (2-1), a titanium layer (2-2), and a steel layer (2-3) from the inside to the outside, the reinforcing rib (10) is fixedly connected to the aluminum layer (2-1) of the aluminum-titanium steel explosion welding block (2), the lower end surface of the anode guide rod (1) is welded to the aluminum layer (2-1) of the aluminum-titanium steel explosion welding block (2) via an aluminum-aluminum lap weld (7), and the upper end surface of the anode steel claw (3) is welded to the steel layer (2-3) of the aluminum-titanium steel explosion welding block (2) via a steel-steel butt weld (8); The aluminum layer (2-1) is provided with a screw hole (12), and the reinforcing rib (10) is a ceramic tube with threads at both ends; The aluminum-titanium steel explosion welding block (2) is composed of four aluminum-titanium steel explosion units, wherein the aluminum-titanium steel explosion units in relative positions among the four aluminum-titanium steel explosion units are fixed by the reinforcing ribs (10), and adjacent aluminum-titanium steel explosion units are welded by corner joints.

2. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1 is characterized in that: The thickness of the titanium layer (2-2) is 0-3 mm, the thickness of the aluminum layer (2-1) is 8-20 mm, and the thickness of the steel layer (2-3) is 30-50 mm; The height of the aluminum-titanium steel explosion welding block (2) is not less than 120 mm.

3. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1 is characterized in that: The distance between the lower end surface of the anode guide rod (1) and the anode steel claw (3) is 5-300 mm.

4. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1 is characterized in that: The aluminum layer (2-1) and the anode guide rod (1) are welded by MIG or TIG argon arc welding, the welding material is aluminum or aluminum silicon welding wire, the welding wire diameter is 2.0 mm, and the welding current is 120-180A.

5. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1, characterized in that: The steel layer (2-3) and the anode steel claw (3) are welded by manual arc welding, gas shielded welding or submerged arc welding, and the welding materials are J422, J507 welding rods or H08 welding wires, and the diameters of the welding rods and welding wires are 3.2 mm and 1.2 mm respectively.

6. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1, characterized in that: The aluminum-titanium steel explosion welding block (2) is welded with the anode guide rod (1) and the anode steel claw (3) in a full welding manner.

7. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 1, characterized in that: A high entropy alloy layer (5) is clad on the side of the steel claw leg (6) of the anode steel claw (3); A layer of high entropy alloy is clad on the surface of the steel-steel butt weld (8).

8. The long-life energy-saving anode conductive device for aluminum electrolysis according to claim 7, characterized in that: The high entropy alloy layer is composed of Fe 30 Co 20 Cr 20 Ni 20 Mo 3.5 .

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