A cathode plate for electrolytic zinc

Abstract

The present invention relates to a cathode plate for electrolytic zinc, belonging to the technical field of zinc electrowinning. The cathode plate for electrolytic zinc of the present invention comprises a conductive beam and an aluminum cathode plate fixedly arranged at the lower end of the conductive beam, wherein a titanium-based / amorphous metal oxide layer is in-situ coated above the liquid level line of the aluminum cathode plate, and a titanium-based / composite ceramic layer is in-situ coated along the vertical direction on both sides of the aluminum cathode plate, the conductive beam comprises a conductive aluminum beam and an aluminum-clad copper composite conductive head fixedly arranged at both ends of the conductive aluminum beam; the amorphous metal oxide layer is Ta-Zr-CaO x The oxide layer comprises a titanium-based / composite ceramic layer composed of a porous nano-TiO2 intermediate layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer. Compared to conventional 1070 aluminum cathode plates, the cathode plate for electrolytic zinc of the present invention has a cathode lifespan that is doubled in electrolytic zinc solutions containing high levels of chlorine and fluoride ions, without changing the electrolytic cell structure. The aluminum cathode plate has a low interface corrosion rate at the liquid level, eliminates the need for side strips, reduces cell voltage by over 10%, and improves current efficiency by over 2%.

Description

Technical Field

[0001] The invention relates to a cathode plate for electrolytic zinc, belonging to the technical field of zinc electrowinning. Background Art

[0002] With the dwindling availability of high-quality zinc concentrate, the raw materials used for electrolytic zinc deposition are becoming increasingly complex, resulting in excessive levels of fluorine and chloride ions in the zinc sulfate solution. This, coupled with the long-term effects of sulfuric acid, F, and Cl, leads to particularly severe corrosion. While the cathode plates immersed in the zinc sulfate solution in the electrolytic tank remain largely intact, they are severely corroded on the upper and side surfaces, rendering them unusable. This shortens the cathode plate's lifespan and increases production costs.

[0003] During zinc electrowinning, zinc ions in the electrolyte are deposited on the cathode plates under the action of direct current, forming metallic zinc. The deposited metallic zinc must be regularly stripped from the cathode plates. This requires the metallic zinc to form a neat end surface at the stripping location, allowing a stripper or other stripping tool to penetrate the gap between the metallic zinc and the plates and separate them. However, in actual production, peak-valley current operation is often employed. Under this operating system, the electrolyte circulation flow rate varies, causing the electrolyte level in the electrolytic cell to fluctuate, forming a slope. Automated zinc stripping has become a new technological development trend in the zinc smelting industry, and this has led to higher requirements for the quality of metallic zinc deposited. However, maintaining a high rate of automated stripping is a major concern for many zinc smelters when considering automated stripping processes. The ability of the deposited zinc to form a smooth stripping end surface is a major factor affecting this rate. Existing solutions generally involve inserting non-metallic insulating strips near the cathode plate liquid level line. The defect of the method of embedding insulating strips is that there is a gap between the insulating strips and the cathode plate. At the same time, the process of embedding insulating strips is complicated. The gap between the insulating strips and the cathode plate will become larger after long-term use. In addition, the non-metallic insulating strips have poor wear resistance. When mechanical stripping of the electrolytically deposited metal is used, the stripping knife for the electrolytically deposited metal is easily blocked, causing feed obstacles and poor practicality.

[0004] There has been considerable research on preventing cathode plate corrosion by spraying coatings or installing side-mounted clamping strips. For example, applying an anti-corrosion coating to the neck surfaces of the cathode and anode plates used in wet electrolytic zinc production can extend the corrosion resistance of the cathode and anode plates. By coating with epoxy resin or heat-resistant anti-corrosion materials, the plate life can be extended to an average of 60 days. Alternatively, anti-corrosion strips can be installed on the upper portion of the plate, exposed to the electrolyte. These strips are made of synthetic materials and are protected from corrosion by harsh gases when installed on the upper portion of the plate, thereby extending the cathode plate's lifespan. Cathode plate coatings have two main drawbacks: a short lifespan and a weak adhesion to the plate, which can lead to bulging and peeling. Alternatively, an anti-corrosion coating consisting of a base layer, an intermediate layer, and a top layer can be applied by spraying or scraping to the area between the cathode plate's liquid level line and the conductive beam, where corrosion is most likely. This anti-corrosion coating can significantly extend the cathode plate's lifespan by 30 to 50 percent, reducing the frequency of aluminum plate replacement. However, the polymer coating can contaminate the electrolyte, thus affecting electrolysis efficiency. The original anti-corrosion treatment for electrolytic cathode aluminum plates usually involves installing polyethylene insulation strips on the plate surface or using an injection molding machine to provide insulation strips. This has a short protection period and is not conducive to subsequent zinc stripping treatment, increasing labor and material costs.

[0005] Furthermore, the conductive rods used in traditional aluminum cathode plates are conductive at one end, and their end joints come in two types: a copper-aluminum clad joint, where molten aluminum is clad onto a block-shaped copper conductor to create a copper-aluminum composite conductor; and a copper-aluminum explosive joint, where the copper block and aluminum rod are bonded together on one side, rather than embedded, on multiple sides. These two types of copper-aluminum composite joints are often used to manufacture small-area aluminum cathode plates for zinc electrowinning due to their high resistivity at the copper-aluminum interface, which leads to heat generation when current is passed, and a relatively low current flow rate. However, these aluminum cathode plates suffer from disadvantages such as a small flow area, a high voltage drop at the ends of the conductive rods, and outdated production processes. Furthermore, the cast conductive beams and lugs inevitably have structural defects such as looseness and porosity. Acid mist can enter these areas, making them difficult to clean during cathode plate cleaning and susceptible to corrosion. Zinc electrowinning processes using traditional aluminum cathode plates suffer from poor adaptability and low production efficiency. Summary of the Invention

[0006] In response to the technical problem that cathode plates for electrolytic zinc have poor resistance to chlorine and fluoride ions, the present invention proposes a chlorine and fluoride ion-resistant cathode plate with excellent electrical conductivity, good metal electrowinning effect, long service life, and convenient mechanical stripping of the electrowinning metal. The cathode product can be effectively stripped without edge strips, thereby reducing production costs and improving labor productivity.

[0007] A cathode plate for electrolytic zinc, comprising a conductive beam 1 and an aluminum cathode plate 2 fixedly mounted at the lower end of the conductive beam 1. The aluminum cathode plate 2 is in-situ coated with a titanium-based / amorphous metal oxide layer 3 above the liquid level line. Both sides of the aluminum cathode plate 2 are in-situ coated with a titanium-based / composite ceramic layer 4 along the vertical direction. The conductive beam 1 comprises a conductive aluminum beam 5 and aluminum-clad copper composite conductive contacts 6 fixedly mounted at both ends of the conductive aluminum beam 5.

[0008] The amorphous metal oxide layer 3 is Ta-Zr-CaO x Oxide layer, the composite ceramic layer 4 is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer.

[0009] The aluminum-clad copper composite conductive head 6 includes a copper substrate, a Cu-Ni-nano-diamond intermediate layer and an aluminum outer layer in sequence from the inside to the outside.

[0010] The conductive aluminum beam 5 includes a hanging ear and a conductive aluminum cross beam. The conductive aluminum beam 5 is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy contains 4-10% Zn, 0.1-0.6% Si, 3-6% Mg, 0.1-1.0% Ce, and the remainder is Al.

[0011] With Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 20-40%, Zr accounts for 30-50%, and Ca accounts for 10-50%.

[0012] The method for preparing the aluminum cathode plate comprises the following specific steps:

[0013] 1) A pure titanium plate is fixed on both sides of a pure aluminum plate and explosively composited to obtain an aluminum-titanium composite plate. The aluminum-titanium composite plate is hot-rolled at a temperature of 300-600°C to obtain an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate.

[0014] 2) Soaking the aluminum-titanium composite horizontal plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating it in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer I;

[0015] 3) Citric acid and ethylene glycol are dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride are added to the anhydrous ethanol, stirred uniformly, and sonicated for 1-3 hours to obtain solution B. Solution A is added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water are added to solution C to obtain a colloidal solution. The solution is sonicated for 10-60 minutes and allowed to stand for 24-48 hours to obtain a sol-gel solution.

[0016] 4) coating the sol-gel solution onto the pretreated titanium substrate layer I and drying to remove anhydrous ethanol and water, sintering the solution at 400-600°C for 5-10 minutes, cooling the solution to room temperature, and repeating the coating-drying-sintering process 5-20 times. The solution is then sintered at 400-600°C for 30-60 minutes to obtain an amorphous metal oxide layer.

[0017] 5) Soaking the aluminum-titanium composite side plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer II of the aluminum-titanium composite side plate;

[0018] 6) Using the pretreated titanium base layer II of the aluminum-titanium composite side plate as the cathode, Pb-1% Ag alloy as the anode, and HF-acetic acid mixture as the electrolyte, anodize at a temperature of 20-40°C and a voltage of 20-30 V for 40-180 min. Remove the aluminum-titanium composite side plate, rinse it with deionized water, and then sinter it at a temperature of 400-600°C for 1-2 h to obtain the titanium base layer II / porous nano-TiO2 layer;

[0019] 7) Nano-ZrO2, ultrafine SiO2 powder, ultrafine Al2O3 powder, and ultrafine B4C powder are added to water glass to prepare an insulating slurry, which is coated on the surface of the titanium base layer II / porous nano-TiO2 layer, dried to remove moisture, and then sintered at a temperature of 100-300°C for 5-10 minutes. The coating-drying-sintering process is repeated 1-5 times to obtain a composite ceramic layer, i.e., a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer;

[0020] 8) The aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding, and the aluminum-titanium composite side plates coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer are welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding to form an aluminum cathode plate.

[0021] In the step 1), the outer layer thickness of the titanium plate in the aluminum-titanium composite horizontal plate and the aluminum-titanium composite side plate is 0.5-2.0 mm;

[0022] In step 2) and step 5), the concentration of the NaOH solution is 10-30 wt.%, and the concentration of the hydrochloric acid solution is 5-30 wt.%;

[0023] Step 3) In solution A, the concentration of citric acid is 0.2-0.6 mol / L, the concentration of ethylene glycol is 1-3 mol / L, the concentration of dilute hydrochloric acid is 0.6-0.9 mol / L, the volume ratio of dilute hydrochloric acid to solution C is 1:20-3:20, and the volume ratio of deionized water to solution C is 1:20-1:5;

[0024] Step 4) the thickness of the amorphous metal oxide layer is 0.5-3 μm;

[0025] Step 6) The HF concentration in the HF-acetic acid mixture is 5-10 wt.%, and the acetic acid concentration is 5-10 wt.%; the thickness of the nano-TiO2 layer is 100-600 nm, the pore size of the nano-TiO2 is 40-80 nm, and the thickness of the composite ceramic layer is 5-100 μm;

[0026] Step 7) The particle size of nano ZrO2 is 20-100 nm, the particle size of SiO2 is 0.1-5 μm, the particle size of Al2O3 is 0.1-5 μm, and the particle size of B4C is 1-10 μm. Based on 100 g of the insulating slurry, the following ingredients are used: 20 g of nano ZrO2, 7 g of ultrafine SiO2 powder, 15 g of ultrafine Al2O3 powder, 5 g of ultrafine B4C powder, and 53 g of water glass; or 25 g of nano ZrO2, 10 g of ultrafine SiO2 powder, 20 g of ultrafine Al2O3 powder, 8 g of ultrafine B4C powder, and 37 g of water glass; or 10 g of nano ZrO2, 5 g of ultrafine SiO2 powder, 6 g of ultrafine Al2O3 powder, 1 g of ultrafine B4C powder, and 73 g of water glass; the thickness of the composite ceramic layer is 5-100 μm.

[0027] The preparation method of the aluminum-clad copper composite conductive head comprises the following specific steps:

[0028] 1) A copper rod was placed in a NaOH solution for degreasing, then activated in an H2SO4 solution for 1-10 min, rinsed with deionized water, and then placed in an alkaline pyrophosphate solution for composite electrodeposition at 40-70°C for 1-10 min. After being rinsed with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained.

[0029] 2) A copper rod coated with a Cu-Ni-nanodiamond intermediate layer is preheated to 100-300°C in a vacuum and then placed in a mold cavity. Aluminum alloy liquid is pressed into the mold cavity at a constant pressure of 6-8 MPa and cooled and solidified at a uniform rate to form an aluminum-clad copper composite conductive head.

[0030] Furthermore, in step 1), the mass concentration of the NaOH solution is 10-20%, the oil removal temperature is 50-79° C., and the time is 1-10 min;

[0031] Furthermore, in step 1), the concentration of the H2SO4 solution is 10-20%, and the time is 2-10 minutes.

[0032] Furthermore, the alkaline pyrophosphate system in step 2) contains 20-40 g / L nickel sulfate, 1-10 g / L copper sulfate, 40-80 g / L potassium pyrophosphate, 0.2-0.5 g / L saccharin, 10-25 g / L sodium acetate, and 2-20 g / L nanodiamond.

[0033] Preferably, the cross-sectional height of the copper substrate is 10-30 mm, and the thickness is 20-60 mm.

[0034] Preferably, the thickness of the Cu-Ni-nanodiamond intermediate layer is 1-5 μm. Taking the mass percentage of the Cu-Ni-nanodiamond intermediate layer as 100%, Ni accounts for 34-70%, Cu accounts for 29.5-60%, nanodiamond accounts for 0.5-6%, and the particle size of the nanodiamond is 10-50 nm.

[0035] A groove is provided at the bottom end of the conductive beam, and the top end of the aluminum cathode plate is inserted into the groove and is welded by aluminum-aluminum stir friction.

[0036] The method for preparing the conductive beam comprises the following specific steps:

[0037] 1) High-purity zinc, Al-2% Si master alloy, Al-10% Mg master alloy, Al-5% Ce, and high-purity aluminum are sequentially added to an intermediate frequency furnace and melted under electromagnetic stirring. Refining agent ZnCl2-KCl is added for refining. The slag is removed and the aluminum alloy melt is pressed from the bottom of the intermediate frequency furnace into a cast iron mold cavity. The mold is formed under constant pressure at a temperature of 400-600°C, cooled and solidified at a uniform rate to room temperature, and then processed into a conductive aluminum beam.

[0038] 2) The aluminum-clad copper composite conductive head is welded to the two ends of the conductive aluminum beam by aluminum-aluminum stir friction welding to obtain a conductive beam.

[0039] Preferably, the cross-sectional height of the conductive aluminum beam is 20-60 mm, the thickness is 20-80 mm, the groove depth of the conductive aluminum beam is 6-20 mm, and the width is 3-10 mm.

[0040] The beneficial effects of the present invention are:

[0041] (1) The cathode plate for electrolytic zinc of the present invention has extremely strong resistance to chlorine and fluoride ions, good electrical conductivity, long service life, and high cathode zinc output. Compared with the traditional 1070 aluminum cathode plate, without changing the structure of the electrolytic cell, in the electrolytic zinc solution containing high chlorine and fluoride ions, the cathode life is extended by 2 times, the corrosion rate of the aluminum cathode plate liquid level interface is low, and no edge strips are required on both sides. The cell voltage is reduced by more than 10%, and the current efficiency is increased by more than 2%;

[0042] (2) The present invention provides aluminum-clad copper composite conductive heads at both ends of the conductive beam, thereby improving the conduction efficiency. By utilizing the thermal oxidation resistance of nanodiamonds, a Cu-Ni-nanodiamond intermediate layer is introduced into the aluminum-clad copper composite conductive head, thereby preventing the oxidation of Cu, promoting heat transfer of the conductive beam, and preventing the aluminum beam from heating up.

[0043] (3) The present invention directly inserts the aluminum cathode plate into the conductive beam and metallurgically welds the beam and plate by stir friction welding, so that the current flows directly from the inside of the conductive beam to the aluminum cathode plate, thereby improving the conduction efficiency of the aluminum cathode plate and the current efficiency of zinc deposition. Compared with the beam-plate welding of the traditional aluminum cathode plate, the defects of pores and corrosion by acid mist can be avoided, thereby increasing the service life of the cathode plate.

[0044] (4) The present invention utilizes explosive welding to prepare titanium-aluminum composite plates. The metallurgical bonding of titanium and aluminum is good, and uniform and fine interface waves are easily formed. During the hot rolling deformation process, the composite plate bonding interface will not be destroyed, and layered composite plates with different thicknesses and high surface quality can be easily obtained.

[0045] (5) The present invention coats the gas-liquid-solid interface of the aluminum cathode plate with titanium-based amorphous Ta-Zr-CaO x The oxide layer can prevent the acid mist containing high chloride ions and fluoride ions from corroding the aluminum cathode plate during the electrolysis process, which is beneficial to extending the service life of the cathode plate. At the same time, it prevents the zinc sheet from being difficult to peel off under the change of the electrolyte circulation flow rate under the peak and valley current working system.

[0046] (6) The present invention coats both sides of the aluminum cathode plate with a titanium-based / porous nano-TiO2 / nano-ZrO2-SiO2-A12O3-B4C composite layer, so that the edge of the cathode plate has insulation, wear resistance and corrosion resistance properties, which can avoid the coating of metal zinc and does not use edge strips, thereby reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the structure of the cathode plate for electrolytic zinc;

[0048] Figure 2 for Figure 1 AA cross-sectional diagram;

[0049] Figure 3 for Figure 1 BB cross-sectional diagram;

[0050] Figure 4 for Figure 1 Schematic diagram of CC cross section;

[0051] Figure 5 for Figure 1 DD cross-sectional diagram;

[0052] In the figure: 1-conductive beam, 2-aluminum cathode plate, 3-titanium base / amorphous metal oxide layer, 3a-titanium base, 3b-Ta-Zr-CaO x Oxide layer, 4-titanium-based composite ceramic layer, 4a-titanium matrix, 4b-porous nano-TiO2 intermediate layer, 4c-nano ZrO2-SiO2-Al2O3-B4C composite compound outer layer, 5-conductive aluminum beam, 6-aluminum-clad copper composite conductive head, 6a-aluminum alloy, 6b-Cu-Ni-nano diamond intermediate layer, 6c-pure copper. DETAILED DESCRIPTION

[0053] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above. SUMMARY OF THE INVENTION

[0055] A cathode plate for electrolytic zinc (see Figure 1-5 ), comprising a conductive beam 1 and an aluminum cathode plate 2 fixedly arranged at the lower end of the conductive beam 1, the aluminum cathode plate 2 being in-situ coated with a titanium-based / amorphous metal oxide layer 3 above the liquid level line, and both sides of the aluminum cathode plate 2 being in-situ coated with a titanium-based / composite ceramic layer 4 along the vertical direction, the conductive beam 1 comprising a conductive aluminum beam 5 and aluminum-clad copper composite conductive heads 6 fixedly arranged at both ends of the conductive aluminum beam 5;

[0056] The amorphous metal oxide layer 3 is Ta-Zr-CaO x Oxide layer, the composite ceramic layer 4 is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer;

[0057] The aluminum-clad copper composite conductive head 6 includes a copper substrate, a Cu-Ni-nanodiamond intermediate layer and an aluminum outer layer from the inside to the outside.

[0058] The conductive aluminum beam 5 includes a hanging ear and a conductive aluminum crossbeam. The conductive aluminum beam 5 is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy comprises 4-10% Zn, 0.1-0.6% Si, 3-6% Mg, 0.1-1.0% Ce, and the balance Al.

[0059] With Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 20-40%, Zr accounts for 30-50%, and Ca accounts for 10-50%.

[0060] The preparation method of the aluminum cathode plate comprises the following specific steps:

[0061] 1) A pure titanium plate is fixed on both sides of a pure aluminum plate and explosively composited to obtain an aluminum-titanium composite plate. The aluminum-titanium composite plate is hot-rolled at a temperature of 300-600°C to obtain an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate.

[0062] 2) Soaking the aluminum-titanium composite horizontal plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating it in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer I;

[0063] 3) Citric acid and ethylene glycol are dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride are added to the anhydrous ethanol, stirred evenly, and sonicated for 1-3 hours to obtain solution B. Solution A is added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water are added to solution C to obtain a colloidal solution. The solution is sonicated for 10-60 minutes and allowed to stand for 24-48 hours to obtain a sol-gel solution.

[0064] 4) coating the sol-gel solution onto the pretreated titanium substrate layer I and drying to remove anhydrous ethanol and water, sintering the solution at 400-600°C for 5-10 minutes, cooling the solution to room temperature, and repeating the coating-drying-sintering process 5-20 times. The solution is then sintered at 400-600°C for 30-60 minutes to obtain an amorphous metal oxide layer.

[0065] 5) Soaking the aluminum-titanium composite side plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer II of the aluminum-titanium composite side plate;

[0066] 6) Using the pretreated titanium base layer II of the aluminum-titanium composite side plate as the cathode, Pb-1% Ag alloy as the anode, and HF-acetic acid mixture as the electrolyte, anodize at a temperature of 20-40°C and a voltage of 20-30 V for 40-180 min. Remove the aluminum-titanium composite side plate, rinse it with deionized water, and then sinter it at a temperature of 400-600°C for 1-2 h to obtain the titanium base layer II / porous nano-TiO2 layer;

[0067] 7) Nano-ZrO2, ultrafine SiO2 powder, ultrafine Al2O3 powder, and ultrafine B4C powder are added to water glass to prepare an insulating slurry, which is coated on the surface of the titanium base layer II / porous nano-TiO2 layer, dried to remove moisture, and then sintered at a temperature of 100-300°C for 5-10 minutes. The coating-drying-sintering process is repeated 1-5 times to obtain a composite ceramic layer, i.e., a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer;

[0068] 8) The aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding, and the aluminum-titanium composite side plates coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer are welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding to form an aluminum cathode plate.

[0069] The preparation method of the aluminum-clad copper composite conductive head has the following specific steps:

[0070] 1) A copper rod was placed in a NaOH solution for degreasing, then activated in an H2SO4 solution for 1-10 min, rinsed with deionized water, and then placed in an alkaline pyrophosphate solution for composite electrodeposition at 40-70°C for 1-10 min. After being rinsed with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained.

[0071] 2) A copper rod coated with a Cu-Ni-nanodiamond intermediate layer is preheated to 100-300°C in a vacuum and then placed in a mold cavity. Aluminum alloy liquid is pressed into the mold cavity at a constant pressure of 6-8 MPa and cooled and solidified at a uniform rate to form an aluminum-clad copper composite conductive head.

[0072] The bottom end of the conductive beam is provided with a groove, the top end of the aluminum cathode plate is inserted into the groove and is welded by aluminum-aluminum stir friction.

[0073] The preparation method of the conductive beam includes the following specific steps:

[0074] 1) High-purity zinc, Al-2% Si master alloy, Al-10% Mg master alloy, Al-5% Ce, and high-purity aluminum are sequentially added to an intermediate frequency furnace and melted under electromagnetic stirring. Refining agent ZnCl2-KCl is added for refining. The slag is removed and the aluminum alloy melt is pressed from the bottom of the intermediate frequency furnace into a cast iron mold cavity. The mold is formed under constant pressure at a temperature of 400-600°C, cooled and solidified at a uniform rate to room temperature, and then processed into a conductive aluminum beam.

[0075] 2) The aluminum-clad copper composite conductive head is welded to the two ends of the conductive aluminum beam by aluminum-aluminum stir friction welding to obtain a conductive beam.

[0076] The present invention introduces nano-diamonds to improve the hardness and heat transfer of the coating, introduces nano-TiO2 film, nano-ZrO2, and ultrafine powder Al2O3 to make the coating non-conductive, resistant to high-temperature oxidation and thermal corrosion, adopts a sol-gel method to prepare amorphous nano-Ta2O5 and ZrO2 particles, which have a high specific surface area under sintering, and adopts stir friction welding to metallurgically weld the beam and plate. The synergistic effect between these particles and the new preparation process greatly improve the conductivity of the electrode, prolong the service life, and facilitate the stripping of zinc sheets. Compared with traditional 1070 aluminum cathode plates, without changing the electrolytic cell structure, the cathode prepared by the present invention has a service life extended by 2 times in high-chlorine and fluoride ion electrolytic zinc solution, the aluminum cathode plate liquid level line interface corrosion rate is low, and no edge strips are required on both sides, the cell voltage is reduced by more than 10%, and the current efficiency is improved by more than 2%.

[0077] Example 1: A cathode plate for electrolytic zinc (see Figure 1 ), comprising a conductive beam 1 and an aluminum cathode plate 2 fixedly arranged at the lower end of the conductive beam 1, the aluminum cathode plate 2 being in-situ coated with a titanium-based / amorphous metal oxide layer 3 above the liquid level line, and both sides of the aluminum cathode plate 2 being in-situ coated with a titanium-based / composite ceramic layer 4 along the vertical direction, the conductive beam 1 comprising a conductive aluminum beam 5 and aluminum-clad copper composite conductive heads 6 fixedly arranged at both ends of the conductive aluminum beam 5;

[0078] The amorphous metal oxide layer 3 is Ta-Zr-CaO x Oxide layer, the composite ceramic layer 4 is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer;

[0079] The aluminum-clad copper composite conductive head 6 (see Figure 5 ) from the inside to the outside, it includes a copper substrate, a Cu-Ni-nanodiamond intermediate layer, and an aluminum outer layer; the cross-sectional height of the copper substrate is 30 mm and the thickness is 40 mm; the thickness of the Cu-Ni-nanodiamond intermediate layer is 3 μm, and based on the mass percentage of the Cu-Ni-nanodiamond intermediate layer being 100%, Ni accounts for 50%, Cu accounts for 47%, and nanodiamond accounts for 3%, and the particle size of the nanodiamond is 30 nm;

[0080] The conductive aluminum beam 5 includes a hanging ear and a conductive aluminum beam. The cross-sectional height of the conductive aluminum beam is 50 mm and the thickness is 40 mm. The conductive aluminum beam 5 is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy contains 6.2% Zn, 0.4% Si, 5% Mg, and 0.5% Ce, with the remainder being Al.

[0081] like Figure 2As shown, a groove is opened at the bottom of the conductive beam, the groove is 12mm deep and 6mm wide, and the top end of the aluminum cathode plate is inserted into the groove and is stir-friction welded to aluminum;

[0082] Ta-Zr-CaO x The oxide layer thickness is 2μm, with Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 40%, Zr accounts for 40%, and Ca accounts for 20%.

[0083] The thickness of the nano ZrO2-SiO2-A12O3-B4C composite compound layer is 40 μm;

[0084] The preparation method of the aluminum cathode plate comprises the following specific steps:

[0085] 1) A pure titanium plate is laminated and fixed on both sides of a pure aluminum plate (1070-H18), and explosives are ignited to form an aluminum-titanium composite plate through explosive bonding. The aluminum-titanium composite plate is then hot-rolled at 450°C to form an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate. The outer layer of the titanium plate in the aluminum-titanium composite horizontal plate and the aluminum-titanium composite side plate has a thickness of 1.0 mm.

[0086] 2) The aluminum-titanium composite horizontal plate was immersed in a NaOH solution at a temperature of 50°C for 30 minutes, washed with deionized water, dried, sandblasted (40 mesh corundum), and then placed in a 20wt.% hydrochloric acid solution and activated at a temperature of 80°C for 1 hour to obtain a pretreated titanium base layer I; the concentration of the NaOH solution was 10wt.%;

[0087] 3) Citric acid and ethylene glycol were dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride were added to anhydrous ethanol, stirred uniformly, and ultrasonically treated for 2 hours to obtain solution B. Solution A was added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water were added to solution C to obtain a colloidal solution, ultrasonically treated for 30 minutes, and allowed to stand for 24 hours to obtain a sol-gel solution. The concentration of citric acid in solution A was 0.45 mol / L, the concentration of ethylene glycol was 2.25 mol / L, and the concentration of dilute hydrochloric acid was 0.75 mol / L. The molar ratio of citric acid, ethylene glycol, and total metals (total molar amount of tantalum, zirconium, and calcium) was 3:15:1. The volume ratio of dilute hydrochloric acid to solution C was 1:10, and the volume ratio of deionized water to solution C was 1:10. Solution B contained 0.06 mol / L tantalum pentachloride, 0.06 mol / L zirconium oxychloride octahydrate, and 0.03 mol / L calcium chloride.

[0088] 4) The sol-gel solution was coated on the pretreated titanium substrate layer I and dried at 120°C for 8 minutes to remove the anhydrous ethanol and water, and then sintered at 500°C for 8 minutes, cooled to room temperature, and the coating-drying-sintering process was repeated 15 times, and then sintered at 500°C for 60 minutes to obtain an amorphous metal oxide layer (see Figure 3 );

[0089] 5) The aluminum-titanium composite side plate was immersed in a NaOH solution at a temperature of 50°C for 30 minutes, washed with deionized water, dried, sandblasted (40 mesh corundum), and then activated in a 20 wt.% hydrochloric acid solution at a temperature of 80°C for 1 hour to obtain the pretreated titanium base layer II of the aluminum-titanium composite side plate;

[0090] 6) Anodizing the pretreated titanium substrate II of the aluminum-titanium composite side plate at 30°C and 25V for 90 minutes using a Pb-1% Ag alloy as the anode and an HF-acetic acid mixture as the electrolyte. The aluminum-titanium composite side plate was removed and rinsed with deionized water, and then sintered at 500°C for 1.5 hours to obtain a titanium substrate II / porous nano-TiO2 layer; wherein the HF-acetic acid mixture had an HF concentration of 8 wt.%, an acetic acid concentration of 8 wt.%, and a nano-TiO2 layer thickness of 400 nm and a nano-TiO2 pore diameter of 60 nm.

[0091] 7) Add 20g of nano ZrO2, 7g of ultrafine SiO2, 15g of ultrafine Al2O3 and 5g of ultrafine B4C to 53g of water glass to prepare an insulating slurry. The insulating slurry is coated on the surface of the titanium base layer II / porous nano TiO2 layer and dried at 120°C for 8min to remove moisture. Then, the slurry is sintered at 200°C for 8min. The coating-drying-sintering process is repeated three times to obtain a composite ceramic layer, i.e., a porous nano TiO2 / nano ZrO2-SiO2-Al2O3-B4C composite layer (see Figure 4 ); the nano ZrO2 particle size is 40nm, the SiO2 particle size is 2μm, the A12O3 particle size is 1μm, and the B4C particle size is 3μm;

[0092] 8) An aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding, and an aluminum-titanium composite side plate coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer is welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding to form an aluminum cathode plate;

[0093] The preparation method of the aluminum-clad copper composite conductive head has the following specific steps:

[0094] 1) First, place the T2 copper rod in a 15% NaOH solution and degrease it at 60°C for 8 minutes, then activate it in a 15% H2SO4 solution for 6 minutes, rinse it with deionized water, and place it in alkaline pyrophosphate at 60°C and a cathode current density of 3A / dm 2 The composite electrodeposition was carried out for 8 min under a mechanical stirring speed of 200 rpm, and after washing with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained;

[0095] 2) A copper rod coated with a Cu-Ni-nanodiamond interlayer was preheated to 200°C in a vacuum oven and placed in a cast iron mold. A vacuum pump was used to press aluminum alloy liquid into the mold at a constant pressure of 7 MPa. The alloy was then cooled and solidified at a constant cooling rate of 20°C / min. The resulting sample was then lathe-machined into an aluminum-clad copper composite conductive contact of the desired size.

[0096] The preparation method of the conductive beam includes the following specific steps:

[0097] 1) High-purity zinc, Al-2% Si master alloy, Al-10% Mg master alloy, Al-5% Ce, and high-purity aluminum were sequentially added to an intermediate frequency furnace and melted under electromagnetic stirring. 50 g of refining agent ZnCl2-KCl was added and refined for 12 min. The slag was removed, and the aluminum alloy melt was sucked out from the bottom of the intermediate frequency furnace using a vacuum pump and pressed into a cast iron mold cavity at a pressure of 6 MPa. The mold was formed under constant pressure at a temperature of 500°C, and then cooled and solidified at a uniform cooling rate of 3°C / min to room temperature to form a conductive aluminum beam with grooves and ears.

[0098] 2) The aluminum-copper composite conductive head is welded to the two ends of the conductive aluminum beam by aluminum-aluminum friction stir welding to obtain a conductive beam;

[0099] The chlorine-fluoride ion-resistant cathode plate for electrolytic zinc prepared in this embodiment was placed in a zinc electrolyte under the following electrolysis conditions: the electrolyte concentration of zinc ions was 50 g / L, sulfuric acid was 150 g / L, chloride ions were 800 mg / L, fluoride ions were 150 mg / L, and the current density was 500 A / m 2 The electrolysis temperature is 38°C. Compared with the traditional 1070 aluminum cathode plate, the cathode life of this chlorine-fluoride ion-resistant electrolytic zinc cathode plate is extended by 2 times, the cell voltage is reduced by 15%, and the current efficiency is increased by 3%.

[0100] Example 2: A cathode plate for electrolytic zinc (see Figure 1 ), comprising a conductive beam 1 and an aluminum cathode plate 2 fixedly arranged at the lower end of the conductive beam 1, the aluminum cathode plate 2 being in-situ coated with a titanium-based / amorphous metal oxide layer 3 above the liquid level line, and both sides of the aluminum cathode plate 2 being in-situ coated with a titanium-based / composite ceramic layer 4 along the vertical direction, the conductive beam 1 comprising a conductive aluminum beam 5 and aluminum-clad copper composite conductive heads 6 fixedly arranged at both ends of the conductive aluminum beam 5;

[0101] The amorphous metal oxide layer 3 is Ta-Zr-CaO x Oxide layer, the composite ceramic layer 4 is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer;

[0102] The aluminum-clad copper composite conductive head 6 (see Figure 5 ) from the inside to the outside, it includes a copper substrate, a Cu-Ni-nanodiamond intermediate layer, and an aluminum outer layer; the cross-sectional height of the copper substrate is 20 mm and the thickness is 60 mm; the thickness of the Cu-Ni-nanodiamond intermediate layer is 5 μm, and based on the mass percentage of the Cu-Ni-nanodiamond intermediate layer being 100%, Ni accounts for 34%, Cu accounts for 60%, and nanodiamond accounts for 6%, and the particle size of the nanodiamond is 50 nm;

[0103] The conductive aluminum beam 5 includes a hanging ear and a conductive aluminum beam. The cross-sectional height of the conductive aluminum beam is 60 mm and the thickness is 60 mm. The conductive aluminum beam 5 is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy comprises 7% Zn, 0.6% Si, 6% Mg, 1.0% Ce, and the balance Al.

[0104] like Figure 2 As shown, a groove is opened at the bottom of the conductive beam, the groove is 20mm deep and 6mm wide, and the top end of the aluminum cathode plate is inserted into the groove and is stirred and welded by aluminum-aluminum friction;

[0105] Ta-Zr-CaO x The oxide layer thickness is 3 μm, with Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 30%, Zr accounts for 40%, and Ca accounts for 30%;

[0106] The thickness of the nano ZrO2-SiO2-Al2O3-B4C composite compound layer is 100 μm;

[0107] The preparation method of the aluminum cathode plate comprises the following specific steps:

[0108] 1) A pure titanium plate is laminated and fixed on both sides of a pure aluminum plate (1060-H18), and explosives are ignited to form an aluminum-titanium composite plate through explosive bonding. The aluminum-titanium composite plate is then hot-rolled at 600°C to form an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate. The outer layer of the titanium plate in the aluminum-titanium composite horizontal plate and the aluminum-titanium composite side plate has a thickness of 2.0 mm.

[0109] 2) The aluminum-titanium composite horizontal plate was immersed in a NaOH solution at a temperature of 70°C for 40 minutes, washed with deionized water, dried, sandblasted (20 mesh corundum), and then placed in a 30wt.% hydrochloric acid solution and activated at a temperature of 100°C for 2 hours to obtain a pretreated titanium base layer I; the concentration of the NaOH solution was 20wt.%;

[0110] 3) Citric acid and ethylene glycol were dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride were added to anhydrous ethanol, stirred uniformly, and sonicated for 3 hours to obtain solution B. Solution A was then added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water were added to solution C to obtain a colloidal solution, sonicated for 60 minutes, and allowed to stand for 48 hours to obtain a sol-gel solution. The concentration of citric acid in solution A was 0.6 mol / L, the concentration of ethylene glycol was 2.8 mol / L, and the concentration of dilute hydrochloric acid was 0.9 mol / L. The molar ratio of citric acid, ethylene glycol, and total metals (total molar amount of tantalum, zirconium, and calcium) was 3:14:1. The volume ratio of dilute hydrochloric acid to solution C was 3:20, and the volume ratio of deionized water to solution C was 1:5. Solution B contained 0.06 mol / L tantalum pentachloride, 0.08 mol / L zirconium oxychloride octahydrate, and 0.06 mol / L calcium chloride.

[0111] 4) The sol-gel solution was coated on the pretreated titanium substrate layer I and dried at 150°C for 10 min to remove anhydrous ethanol and water, and then sintered at 600°C for 10 min, cooled to room temperature, and the coating-drying-sintering process was repeated 20 times, and then sintered at 600°C for 60 min to obtain an amorphous metal oxide layer (see Figure 3 );

[0112] 5) The aluminum-titanium composite side plate was immersed in a NaOH solution at a temperature of 70°C for 40 minutes, washed with deionized water, dried, sandblasted (20 mesh corundum), and then activated in a 30 wt.% hydrochloric acid solution at a temperature of 100°C for 2 hours to obtain the pretreated titanium base layer II of the aluminum-titanium composite side plate;

[0113] 6) Anodizing the pretreated titanium substrate II of the aluminum-titanium composite side plate at 40°C and 30V for 180 min using a Pb-1% Ag alloy as the anode and an HF-acetic acid mixture as the electrolyte. The aluminum-titanium composite side plate was removed and rinsed with deionized water, and then sintered at 600°C for 2 h to obtain a titanium substrate II / porous nano-TiO2 layer; wherein the HF-acetic acid mixture had an HF concentration of 10 wt.% and an acetic acid concentration of 10 wt.%. The nano-TiO2 layer had a thickness of 600 nm and a nano-TiO2 pore size of 80 nm.

[0114] 7) Add 25g of nano ZrO2, 10g of ultrafine SiO2, 20g of ultrafine Al2O3 and 8g of ultrafine B4C to 37g of water glass to prepare an insulating slurry. The insulating slurry is coated on the surface of the titanium base layer II / porous nano TiO2 layer and dried at 150°C for 10 minutes to remove moisture. Then, the slurry is sintered and cured at 300°C for 10 minutes. The coating-drying-sintering process is repeated 5 times to obtain a composite ceramic layer, i.e., a porous nano TiO2 / nano ZrO2-SiO2-Al2O3-B4C composite layer (see Figure 4 ); the nano ZrO2 particle size is 100nm, the SiO2 particle size is 5μm, the Al2O3 particle size is 5μm, and the B4C particle size is 10μm;

[0115] 8) An aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding, and an aluminum-titanium composite side plate coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer is welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding to form an aluminum cathode plate;

[0116] The preparation method of the aluminum-clad copper composite conductive head has the following specific steps:

[0117] 1) First, place the T2 copper rod in a 20% NaOH solution and degrease it at 70°C for 10 minutes, then activate it in a 20% H2SO4 solution for 10 minutes, rinse it with deionized water, and place it in alkaline pyrophosphate at 70°C and a cathode current density of 6A / dm 2 The composite electrodeposition was carried out for 10 min under a mechanical stirring speed of 300 rpm, and after washing with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained;

[0118] 2) A copper rod coated with a Cu-Ni-nanodiamond interlayer was preheated to 300°C in a vacuum oven and placed in a cast iron mold. A vacuum pump was used to press aluminum alloy liquid into the mold at a constant pressure of 8 MPa. The alloy was cooled and solidified at a constant rate of 30°C / min. The resulting sample was then lathe-machined into an aluminum-clad copper composite conductive contact of the desired size.

[0119] The preparation method of the conductive beam includes the following specific steps:

[0120] 1) High-purity zinc, Al-2% Si master alloy, Al-10% Mg master alloy, Al-5% Ce, and high-purity aluminum were sequentially added to an intermediate frequency furnace and melted under electromagnetic stirring. 50 g of refining agent ZnCl2-KCl was added and refined for 20 min. The slag was removed, and the aluminum alloy melt was sucked out from the bottom of the intermediate frequency furnace using a vacuum pump and pressed into a cast iron mold cavity at a pressure of 12 MPa. The mold was formed under constant pressure at a temperature of 600°C, and then cooled and solidified at a uniform cooling rate of 5°C / min to room temperature to form a conductive aluminum beam with grooves and ears.

[0121] 2) The aluminum-copper composite conductive head is welded to the two ends of the conductive aluminum beam by aluminum-aluminum friction stir welding to obtain a conductive beam;

[0122] The chlorine-fluoride ion-resistant cathode plate for electrolytic zinc prepared in this embodiment was placed in a zinc electrolyte under the following electrolysis conditions: the electrolyte concentration of zinc ions was 50 g / L, sulfuric acid was 150 g / L, chloride ions were 800 mg / L, fluoride ions were 150 mg / L, and the current density was 500 A / m 2 The electrolysis temperature is 38°C. Compared with the traditional 1070 aluminum cathode plate, the cathode life of this chlorine-fluoride ion-resistant electrolytic zinc cathode plate is extended by 1.5 times, the cell voltage is reduced by 10%, and the current efficiency is increased by 1.5%.

[0123] Example 3: A cathode plate for electrolytic zinc (see Figure 1 ), comprising a conductive beam 1 and an aluminum cathode plate 2 fixedly arranged at the lower end of the conductive beam 1, the aluminum cathode plate 2 being in-situ coated with a titanium-based / amorphous metal oxide layer 3 above the liquid level line, and both sides of the aluminum cathode plate 2 being in-situ coated with a titanium-based / composite ceramic layer 4 along the vertical direction, the conductive beam 1 comprising a conductive aluminum beam 5 and aluminum-clad copper composite conductive heads 6 fixedly arranged at both ends of the conductive aluminum beam 5;

[0124] The amorphous metal oxide layer 3 is Ta-Zr-CaO x Oxide layer, the composite ceramic layer 4 is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer;

[0125] The aluminum-clad copper composite conductive head 6 (see Figure 5 ) from the inside to the outside, it includes a copper substrate, a Cu-Ni-nanodiamond intermediate layer, and an aluminum outer layer; the cross-sectional height of the copper substrate is 10 mm and the thickness is 20 mm; the thickness of the Cu-Ni-nanodiamond intermediate layer is 1 μm, and based on the mass percentage of the Cu-Ni-nanodiamond intermediate layer being 100%, Ni accounts for 70%, Cu accounts for 29.5%, and nanodiamond accounts for 0.5%, and the particle size of the nanodiamond is 10 nm;

[0126] The conductive aluminum beam 5 includes a hanging ear and a conductive aluminum beam. The cross-sectional height of the conductive aluminum beam is 30 mm and the thickness is 20 mm. The conductive aluminum beam 5 is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy comprises 4% Zn, 0.1% Si, 3% Mg, 0.1% Ce, and the remainder Al.

[0127] like Figure 2 As shown, a groove is opened at the bottom of the conductive beam, the groove is 6mm deep and 5mm wide, and the top end of the aluminum cathode plate is inserted into the groove and is stirred and welded by aluminum-aluminum friction;

[0128] Ta-Zr-CaO x The oxide layer thickness is 0.5 μm, with Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 20%, Zr accounts for 50%, and Ca accounts for 30%;

[0129] The thickness of the nano ZrO2-SiO2-Al2O3-B4C composite compound layer is 5 μm;

[0130] The preparation method of the aluminum cathode plate comprises the following specific steps:

[0131] 1) A pure titanium plate is laminated and fixed on both sides of a pure aluminum plate (1070-H18), and explosives are ignited to form an aluminum-titanium composite plate through explosive bonding. The aluminum-titanium composite plate is then hot-rolled at 300°C to form an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate. The outer layer of the titanium plate in the aluminum-titanium composite horizontal plate and the aluminum-titanium composite side plate has a thickness of 0.5 mm.

[0132] 2) The aluminum-titanium composite horizontal plate was immersed in a NaOH solution at 40°C for 20 minutes, washed with deionized water, dried, sandblasted (100 mesh corundum), and then activated in a 10 wt.% hydrochloric acid solution at 80°C for 0.5 h to obtain a pretreated titanium base layer I; the NaOH solution concentration was 10 wt.%;

[0133] 3) Citric acid and ethylene glycol were dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride were added to anhydrous ethanol, stirred uniformly, and sonicated for 1 hour to obtain solution B. Solution A was added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water were added to solution C to obtain a colloidal solution, sonicated for 10 minutes, and allowed to stand for 24 hours to obtain a sol-gel solution. The concentration of citric acid in solution A was 0.21 mol / L, the concentration of ethylene glycol was 1.19 mol / L, and the concentration of dilute hydrochloric acid was 0.6 mol / L. The molar ratio of citric acid, ethylene glycol, and total metals (total molar amount of tantalum, zirconium, and calcium) was 3:17:1. The volume ratio of dilute hydrochloric acid to solution C was 1:20, and the volume ratio of deionized water to solution C was 1:20. Solution B contained 0.042 mol / L tantalum pentachloride, 0.105 mol / L zirconium oxychloride octahydrate, and 0.063 mol / L calcium chloride.

[0134] 4) The sol-gel solution was coated on the pretreated titanium substrate layer I and dried at 100°C for 5 min to remove the anhydrous ethanol and water, and then sintered at 400°C for 5 min, cooled to room temperature, and the coating-drying-sintering process was repeated 5 times, and then sintered at 400°C for 30 min to obtain an amorphous metal oxide layer (see Figure 3 );

[0135] 5) The aluminum-titanium composite side plate was immersed in a NaOH solution at a temperature of 40°C for 20 minutes, washed with deionized water, dried, sandblasted (100 mesh corundum), and then activated in a 10 wt.% hydrochloric acid solution at a temperature of 80°C for 0.5 hours to obtain the pretreated titanium base layer II of the aluminum-titanium composite side plate;

[0136] 6) Using the pretreated titanium substrate layer II of the aluminum-titanium composite side plate as the cathode, Pb-1% Ag alloy as the anode, and HF-acetic acid mixture as the electrolyte, anodization was performed at 20°C and 20V for 40 minutes. The aluminum-titanium composite side plate was removed and rinsed with deionized water, and then sintered at 400°C for 1 hour to obtain the titanium substrate layer II / porous nano-TiO2 layer; wherein the HF concentration in the HF-acetic acid mixture was 5 wt.%, the acetic acid concentration was 5 wt.%, the nano-TiO2 layer thickness was 100 nm, and the nano-TiO2 pore size was 40 nm;

[0137] 7) Add 10g of nano ZrO2, 5g of ultrafine SiO2, 6g of ultrafine Al2O3 and 1g of ultrafine B4C into 73g of water glass to prepare an insulating slurry. The insulating slurry is coated on the surface of the titanium base layer II / porous nano TiO2 layer and dried at 100°C for 5min to remove moisture. Then, the slurry is sintered at 100°C for 5min. The coating-drying-sintering process is repeated once to obtain a composite ceramic layer, i.e., a porous nano TiO2 / nano ZrO2-SiO2-Al2O3-B4C composite layer (see Figure 4 ); the nano ZrO2 particle size is 20nm, the SiO2 particle size is 0.1μm, the Al2O3 particle size is 0.1μm, and the B4C particle size is 1μm;

[0138] 8) An aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding, and an aluminum-titanium composite side plate coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer is welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum friction stir welding to form an aluminum cathode plate;

[0139] The preparation method of the aluminum-clad copper composite conductive head has the following specific steps:

[0140] 1) First, place the T2 copper rod in a 10% NaOH solution and degrease it at 50℃ for 2 minutes. Then, place it in a 10% H2SO4 solution for activation for 2 minutes. After washing with deionized water, place it in alkaline pyrophosphate and activate it at 50℃ and a cathode current density of 1A / dm 2 The composite electrodeposition was carried out for 2 min under a mechanical stirring speed of 100 rpm, and after washing with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained;

[0141] 2) A copper rod coated with a Cu-Ni-nanodiamond interlayer was preheated to 100°C in a vacuum oven and placed in a cast iron mold cavity. A vacuum pump was used to press aluminum alloy liquid into the mold cavity at a constant pressure of 6 MPa. The alloy was cooled and solidified at a constant rate of 10°C / min. The resulting sample was then lathe-machined into an aluminum-clad copper composite conductive contact of the desired size.

[0142] The preparation method of the conductive beam includes the following specific steps:

[0143] 1) High-purity zinc, Al-2%Si master alloy, Al-10%Mg master alloy, Al-5%Ce, and high-purity aluminum were sequentially added to an intermediate frequency furnace and melted under electromagnetic stirring. 50 g of refining agent ZnCl2-KCl was added and refined for 5 min. The slag was removed, and the aluminum alloy melt was sucked out from the bottom of the intermediate frequency furnace using a vacuum pump and pressed into a cast iron mold cavity at a pressure of 1 MPa. The mold was formed under constant pressure at a temperature of 400°C, and then cooled and solidified at a uniform cooling rate of 1°C / min to room temperature to form a conductive aluminum beam with grooves and ears.

[0144] 2) The aluminum-copper composite conductive head is welded to the two ends of the conductive aluminum beam by aluminum-aluminum friction stir welding to obtain a conductive beam;

[0145] The chlorine-fluoride ion-resistant cathode plate for electrolytic zinc prepared in this embodiment was placed in a zinc electrolyte under the following electrolysis conditions: the electrolyte concentration of zinc ions was 50 g / L, sulfuric acid was 150 g / L, chloride ions were 800 mg / L, fluoride ions were 150 mg / L, and the current density was 500 A / m 2 The electrolysis temperature is 38°C. Compared with the traditional 1070 aluminum cathode plate, the cathode life of this chlorine-fluoride ion-resistant electrolytic zinc cathode plate is doubled, the cell voltage is reduced by 10%, and the current efficiency is increased by 1%.

[0146] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A cathode plate for electrolytic zinc, characterized in that: The conductive beam (1) comprises an aluminum cathode plate (2) fixedly arranged at the lower end of the conductive beam (1); the aluminum cathode plate (2) is in-situ coated with a titanium-based / amorphous metal oxide layer (3) above the liquid level line; both sides of the aluminum cathode plate (2) are in-situ coated with a titanium-based / composite ceramic layer (4) along the vertical direction; and the conductive beam (1) comprises a conductive aluminum beam (5) and aluminum-clad copper composite conductive heads (6) fixedly arranged at both ends of the conductive aluminum beam (5); The amorphous metal oxide layer (3) is Ta-Zr-CaO x Oxide layer, the composite ceramic layer (4) is composed of a porous nano-TiO2 middle layer and a nano-ZrO2-SiO2-Al2O3-B4C composite outer layer; Ta-Zr-CaO x The total molar amount of Ta, Zr and Ca in the oxide layer is 100%, Ta accounts for 20-40%, Zr accounts for 30-50%, and Ca accounts for 10-50%; The preparation method of the aluminum cathode plate comprises the following specific steps: 1) A pure titanium plate is fixed on both sides of a pure aluminum plate and explosively composited to obtain an aluminum-titanium composite plate. The aluminum-titanium composite plate is hot-rolled at a temperature of 300-600°C to obtain an aluminum-titanium composite horizontal plate and an aluminum-titanium composite side plate. 2) Soaking the aluminum-titanium composite horizontal plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating it in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer I; 3) Citric acid and ethylene glycol are dissolved in anhydrous ethanol to obtain solution A. Tantalum pentachloride, zirconium oxychloride octahydrate, and calcium chloride are added to the anhydrous ethanol, stirred uniformly, and sonicated for 1-3 hours to obtain solution B. Solution A is added dropwise to solution B under stirring to obtain solution C. Dilute hydrochloric acid and deionized water are added to solution C to obtain a colloidal solution. The solution is sonicated for 10-60 minutes and allowed to stand for 24-48 hours to obtain a sol-gel solution. 4) coating the sol-gel solution onto the pretreated titanium substrate layer I and drying to remove anhydrous ethanol and water, sintering the solution at a temperature of 400-600° C. for 5-10 minutes, cooling the solution to room temperature, repeating the coating-drying-sintering process 5-20 times, and sintering the solution at a temperature of 400-600° C. for 30-60 minutes to obtain an amorphous metal oxide layer having a thickness of 0.5-3 μm; 5) Soaking the aluminum-titanium composite side plate in a NaOH solution at a temperature of 40-70°C for 20-40 minutes, washing with deionized water, drying, sandblasting, and then activating in a hydrochloric acid solution at a temperature of 80-100°C for 0.5-2 hours to obtain a pretreated titanium base layer II of the aluminum-titanium composite side plate; 6) Using the pretreated titanium base layer II of the aluminum-titanium composite side plate as the cathode, Pb-1% Ag alloy as the anode, and HF-acetic acid mixture as the electrolyte, anodize at a temperature of 20-40°C and a voltage of 20-30 V for 40-180 min. Remove the aluminum-titanium composite side plate, rinse it with deionized water, and then sinter it at a temperature of 400-600°C for 1-2 h to obtain the titanium base layer II / porous nano-TiO2 layer; 7) Nano ZrO2, ultrafine SiO2 powder, ultrafine Al2O3 powder and ultrafine B4C powder are added to water glass to prepare an insulating slurry, which is coated on the surface of the titanium base layer II / porous nano TiO2 layer and dried to remove moisture. The slurry is then sintered at a temperature of 100-300°C for 5-10 minutes, and the coating-drying-sintering process is repeated 1-5 times to obtain a composite ceramic layer, i.e., a porous nano TiO2 / nano ZrO2-SiO2-Al2O3-B4C composite layer; the composite ceramic layer has a thickness of 5-100 μm; based on 100 g of the insulating slurry, the nano ZrO2 is 20 g, the ultrafine SiO2 powder is 7 g, the ultrafine Al2O3 powder is 15 g, and the ultrafine B4C powder is 15 g. 5g, water glass 53g; or based on 100g of insulating slurry, nano ZrO2 25g, ultrafine powder SiO2 10g, ultrafine powder Al2O3 20g, ultrafine powder B4C 8g, water glass 37g; or based on 100g of insulating slurry, nano ZrO2 10g, ultrafine powder SiO2 5g, ultrafine powder Al2O3 6g, ultrafine powder B4C 1g, water glass 73g; 8) The aluminum-titanium composite horizontal plate coated with an amorphous metal oxide layer is welded to the top of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding, and the aluminum-titanium composite side plates coated with a porous nano-TiO2 / nano-ZrO2-SiO2-Al2O3-B4C composite layer are welded to both sides of the pure aluminum cathode plate body by aluminum-aluminum stir friction welding to form an aluminum cathode plate.

2. The cathode plate for electrolytic zinc according to claim 1, characterized in that: The aluminum-clad copper composite conductive head (6) comprises, from the inside to the outside, a copper substrate, a Cu-Ni-nano-diamond intermediate layer and an aluminum outer layer.

3. The cathode plate for electrolytic zinc according to claim 1, characterized in that: The conductive aluminum beam (5) includes a hanging ear and a conductive aluminum beam. The conductive aluminum beam (5) is composed of an AlZnSiMgCe alloy. In terms of mass percentage, the AlZnSiMgCe alloy contains 4-10% Zn, 0.1-0.6% Si, 3-6% Mg, 0.1-1.0% Ce, and the remainder is Al.

4. The cathode plate for electrolytic zinc according to claim 1, characterized in that: Step 1) The outer layer thickness of the titanium plate in the aluminum-titanium composite horizontal plate and the aluminum-titanium composite side plate is 0.5-2.0 mm; In step 2) and step 5), the concentration of the NaOH solution is 10-30 wt.%, and the concentration of the hydrochloric acid solution is 5-30 wt.%; Step 3) In solution A, the concentration of citric acid is 0.2-0.6 mol / L, the concentration of ethylene glycol is 1-3 mol / L, the concentration of dilute hydrochloric acid is 0.6-0.9 mol / L, the volume ratio of dilute hydrochloric acid to solution C is 1:20-3:20, and the volume ratio of deionized water to solution C is 1:20-1:5; Step 6) The thickness of the nano-TiO2 layer is 100-600 nm, and the nano-TiO2 pore size is 40-80 nm; Step 7) The HF concentration in the HF-acetic acid mixture is 5-10 wt.%, the acetic acid concentration is 5-10 wt.%, the nano ZrO2 particle size is 20-100 nm, the SiO2 particle size is 0.1-5 μm, the Al2O3 particle size is 0.1-5 μm, and the B4C particle size is 1-10 μm.

5. The cathode plate for electrolytic zinc according to claim 2, characterized in that: The preparation method of the aluminum-clad copper composite conductive head has the following specific steps: 1) A copper rod was placed in a NaOH solution for degreasing, then activated in an H2SO4 solution for 1-10 min, rinsed with deionized water, and then placed in an alkaline pyrophosphate solution for composite electrodeposition at 40-70°C for 1-10 min. After being rinsed with deionized water, a copper rod coated with a Cu-Ni-nanodiamond intermediate layer was obtained. 2) A copper rod coated with a Cu-Ni-nanodiamond intermediate layer is preheated to 100-300°C in a vacuum and then placed in a mold cavity. Aluminum alloy liquid is pressed into the mold cavity at a constant pressure of 6-8 MPa and cooled and solidified at a uniform rate to form an aluminum-clad copper composite conductive head.

6. The cathode plate for electrolytic zinc according to claim 5, characterized in that: Step 1) The alkaline pyrophosphate system contains 20-40 g / L nickel sulfate, 1-10 g / L copper sulfate, 40-80 g / L potassium pyrophosphate, 0.2-0.5 g / L saccharin, 10-25 g / L sodium acetate, and 2-20 g / L nanodiamond.

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