A method for improving electrochemical performance of lead alloy anodes by using rare earths

Abstract

This invention discloses a method for improving the electrochemical performance of lead alloy anodes using rare earth elements. The method includes first melting a rare earth alloy in a vacuum furnace, adding lanthanum (La), cerium (Ce), and neodymium (Nd) while using electromagnetic stirring, controlling the temperature at 850℃~1030℃ for 0.5-1 h. Next, the rare earth alloy concentration is diluted ≤10 times, and dispersants and antioxidants are added. Mechanical stirring combined with electromagnetic stirring is used to ensure uniform elemental composition, controlling the temperature at 500℃~550℃ for 0.5 h to prepare a rare earth master alloy. Then, 5% of the rare earth master alloy, 1% of a lead-calcium alloy, and 1% of a lead-strontium alloy are sequentially added to the molten lead, along with an antioxidant. Mechanical stirring combined with electromagnetic stirring is used to ensure uniform microstructure and composition, controlling the temperature at 450℃~500℃ for 0.5 h to finally obtain a rare earth lead alloy. This method can be applied to the production of anode plates for zinc electrowinning.

Description

Technical Field

[0001] This invention patent belongs to the field of hydrometallurgical technology, specifically relating to a method for improving the electrochemical performance of lead alloy anodes for zinc electrowinning using rare earth elements. Background Technology

[0002] Zinc possesses excellent rollability, wear resistance, corrosion resistance, and castability, as well as good mechanical properties at room temperature. It can be alloyed with various metals to form high-performance alloys. It is widely used in the automotive, construction, home appliance, shipbuilding, light industry, machinery, and battery industries. Currently, it ranks second only to copper and aluminum in non-ferrous metal consumption. Most zinc in the consumer market is obtained through hydrometallurgy. Hydrometallurgy has technological advantages such as low energy consumption, low pollution, low investment, and low production costs, and has a large-scale application in the metallurgical field, especially in the hydrometallurgical zinc industry. More than 85% of the world's zinc production capacity uses hydrometallurgy. The mainstream process for hydrometallurgical zinc refining includes high-temperature roasting of zinc concentrate, leaching, purification, and electrowinning.

[0003] Zinc electrowinning is an important method in hydrometallurgical zinc refining and one of the mainstream applications in electrochemical engineering. Its principle involves using lead as the base material to create an alloy anode and aluminum as the cathode. Under the influence of direct current, electrons are released from the anode surface to generate oxygen, while zinc ions in the electrolyte accept electrons and deposit on the cathode plate to form metallic zinc. The corrosion resistance and electrocatalytic activity of the anode plate are the core components affecting the energy consumption, zinc deposition quality, and production cost of the electrowinning process.

[0004] Currently, lead-based multi-element alloy anodes are mainly used for anode plates in the zinc electrowinning industry. These anodes have technical advantages such as stable production technology, low cost, and high efficiency. However, anode plates made of this material are prone to high resistivity, poor corrosion resistance, and high oxygen evolution potential due to electrolyte environmental factors. This can lead to problems such as poor zinc quality, short anode lifespan, and high DC power consumption.

[0005] To meet the needs of industrial production, this paper proposes a method to improve the electrochemical performance of lead alloy anodes using rare earth elements. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for improving the electrochemical performance of lead alloy anodes using rare earth elements, which offers excellent electrodeposition performance and significant energy reduction.

[0007] To achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: a method for improving the anodic electrochemical performance of lead alloys using rare earth elements, characterized by comprising the following steps: S1. Rare earth alloys are smelted in a vacuum furnace, with lanthanum (La), cerium (Ce), and neodymium (Nd) added. Electromagnetic stirring is used to ensure uniform elemental composition. The temperature is controlled at 850℃~1030℃, and the smelting time is 0.5-1 h. The resulting ingot is cast to obtain the La-Ce-Nd rare earth alloy. S2. A rare earth master alloy is prepared by vacuum furnace melting. The rare earth alloy in S1 is made into rice grains and melted with lead (Pb) to prepare a rare earth master alloy. The alloy concentration is diluted 10 times and an antioxidant is added. Mechanical stirring and electromagnetic stirring are used to ensure uniform composition. The temperature is controlled at 500℃~550℃ and the melting time is 0.5 h. The Pb-La-Ce-Nd master alloy is obtained by casting ingot. S3. Add 0.5~1.55% rare earth master alloy, 4~6% lead-silver alloy, 0.5~1.51% lead-calcium alloy, and 0.5~1.51% lead-strontium alloy, with the balance being refined lead, to the molten lead in sequence. Add an antioxidant, and use mechanical stirring and electromagnetic stirring to ensure uniform composition. Control the temperature at 450℃~500℃ and the melting time at 0.5 h to finally obtain the rare earth lead alloy used for processing anode plates.

[0008] Preferably, the components of lanthanum, cerium, neodymium and antioxidant in S1 include 13-17% lanthanum, 18-22% cerium, 13-17% neodymium and 48-52% antioxidant.

[0009] Preferably, the components of lanthanum, cerium, neodymium and antioxidant in S1 include 15% lanthanum, 20% cerium, 15% neodymium and 50% antioxidant.

[0010] Preferably, the diluted rare earth master alloy in S2 comprises 1.3-1.7% lanthanum, 1.8-2.2% cerium, and 1.3-1.7% neodymium.

[0011] Preferably, the diluted rare earth intermediate alloy in S2 comprises 1.5% lanthanum, 2.0% cerium, and 1.5% neodymium.

[0012] Preferably, the alloy components added to the molten lead in S3 are: 5% rare earth intermediate alloy, 1% lead-calcium alloy, 1% lead-strontium alloy, with the balance being lead, and the calcium alloy containing 10% calcium and the lead-strontium alloy containing 10% strontium.

[0013] Based on the above technical solution, the present invention provides a rare earth lead alloy, which is prepared by a method of improving the anodic electrochemical performance of lead alloy using rare earth elements.

[0014] Based on the above technical solution, the present invention provides an application of rare earth lead alloy in the production of zinc electrowinning anode plates.

[0015] The beneficial effects of this invention are: The anode plates produced by the method of this invention are more adaptable to the current electrolyte environment of mineral materials. Zinc electrowinning experiments have shown that the use of rare earth elements significantly improves the electrochemical performance of lead alloy anodes. Due to the superior oxidation resistance, elastic deformation resistance, lead lattice filling, and protective film repair functions of rare earth elements, the anode resistivity is significantly reduced, the corrosion rate is lowered, the oxygen evolution overpotential is reduced, and the energy consumption per ton of zinc produced is also reduced. Therefore, its electrowinning performance will be even better, the energy consumption reduction effect will be more significant, and the production process and product quality of anode and cathode plates for zinc electrowinning will be further improved. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Those skilled in the art can obtain other drawings based on these drawings without creative effort. Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example 1

[0018] like Figure 1 As shown, the prior art in this embodiment has the following problems: The inventors have found that the anode plates in the zinc electrowinning industry are mainly lead alloy anodes. These anodes have technical advantages such as stable production technology, low cost, and high efficiency. However, anode plates made of this material have shortcomings such as high resistivity, poor corrosion resistance, and high anode oxygen evolution potential, which will cause problems such as poor zinc quality, short anode service life, and high DC power consumption.

[0019] Therefore, the inventors provide a method for improving the electrochemical performance of lead alloy anodes using rare earth elements, characterized by the following steps: S1. Rare earth alloys are smelted in a vacuum furnace, with lanthanum (La), cerium (Ce), and neodymium (Nd) added. Electromagnetic stirring is used to ensure uniform elemental composition. The temperature is controlled at 850℃~1030℃, and the smelting time is 0.5-1 h. The resulting ingot is cast to obtain the La-Ce-Nd rare earth alloy. Furthermore, the components of lanthanum, cerium, neodymium, and antioxidant in S1 include 13-17% lanthanum, 18-22% cerium, 13-17% neodymium, and 48-52% antioxidant. Furthermore, the components of lanthanum, cerium, neodymium, and antioxidant in S1 include 15% lanthanum, 20% cerium, 15% neodymium, and 50% antioxidant. S2. A rare earth master alloy is prepared by vacuum furnace melting. The rare earth alloy in S1 is made into rice grains and melted with lead (Pb) to prepare a rare earth master alloy. The alloy concentration is diluted 10 times and an antioxidant is added. Mechanical stirring and electromagnetic stirring are used to ensure uniform composition. The temperature is controlled at 500℃~550℃ and the melting time is 0.5 h. The Pb-La-Ce-Nd master alloy is obtained by casting ingot. Furthermore, the diluted rare earth master alloy in S2 comprises 1.3-1.7% lanthanum, 1.8-2.2% cerium, and 1.3-1.7% neodymium; Furthermore, the diluted rare earth master alloy in S2 comprises 1.5% lanthanum, 2.0% cerium, and 1.5% neodymium; S3. Add 0.5~1.55% rare earth master alloy, 4~6% lead-silver alloy, 0.5~1.51% lead-calcium alloy, and 0.5~1.51% lead-strontium alloy, with the balance being refined lead, to the molten lead in sequence. Add an antioxidant, use mechanical stirring and electromagnetic stirring to ensure uniform composition, control the temperature at 450℃~500℃, and smelt for 0.5 h to finally obtain the rare earth lead alloy used for processing anode plates. Furthermore, the alloy components added to the molten lead in S3 are: 5% rare earth intermediate alloy, 1% lead-calcium alloy, 1% lead-strontium alloy, with the balance being lead, and the calcium alloy containing 10% calcium and the lead-strontium alloy containing 10% strontium.

[0020] Based on the above technical solution, the present invention provides a rare earth lead alloy, which is prepared by a method of improving the anodic electrochemical performance of lead alloy using rare earth elements.

[0021] Based on the above technical solution, the present invention provides an application of rare earth lead alloy in the production of zinc electrowinning anode plates. Example 2

[0022] Based on the above embodiments, the inventors conducted the following comparative experiments: (1) Mechanics Experiment The inventors conducted physical experiments on the rare earth lead alloy anode plates prepared using the above-mentioned rare earth addition technology and compared them with anode plates without rare earth alloy addition. The results are shown in the table below: ; Experimental results show that the mechanical properties of lead alloy anodes made with rare earth additives can be equal to or improved compared to the original materials, and rare earth alloys have a positive effect on the durability of anode plates. (2) Electrochemical experiments The inventors prepared a rare-earth lead alloy anode plate using the above-mentioned technical solution, and set the following parameters: sulfuric acid concentration of 160 g / L, zinc ion concentration of electrolyte of 50 g / L, and current density of 500 A / m. 2 The cell voltage was controlled at an electrowinning environment of 3.2-3.5 V. Electrochemical performance was compared with that of lead alloy anode plates without rare earth elements in existing technologies during zinc electrowinning experiments, as detailed below: ; Experimental results show that the addition of rare earth elements significantly improves the electrochemical performance of lead alloy anodes, reducing anode resistivity by 7.31%, enhancing conductivity and corrosion resistance; reducing corrosion rate by 16.22%, increasing service life; reducing oxygen evolution overpotential by 6.34%, effectively reducing cell voltage, reducing energy consumption, and improving electrowinning efficiency and economy; and reducing power consumption by 1.86%, indicating a power saving of 60 kWh per ton of zinc produced, thus improving cost-effectiveness. Therefore, it can be concluded that lead alloy anode plates with added rare earth elements have significantly improved mechanical properties, which is beneficial to the product's durability. They also have excellent overall electrowinning performance, resulting in more significant reductions in energy consumption and increased production, further improving the product quality and technological value of zinc electrowinning anode plates.

[0023] Furthermore, the addition of rare earth elements reduced the Poisson's ratio and plasticity of the alloy. Experiments show that all solid solution lead alloys still have strong plasticity.

[0024] The Fermi level density of states of the alloy increases with increasing addition amount. Each rare earth element has a different effect on the Fermi level of the lead alloy; the addition of Nd results in the highest Fermi level density of states, implying a lower electrode potential. Using Fermi level density of states as a selection criterion, Ce, La, and Nd can be chosen as alloying elements. Therefore, rare earth master alloys have a significant impact on the electrochemical efficiency produced in an electrochemical field. Comparative analysis of mechanical properties and electrode potential shows that Nd and La are the alloying elements that can improve the overall performance of lead alloys among the six rare earth elements, with Nd being the most superior. In electrochemical experiments, the anode with the lowest average cell voltage and the most significant energy-saving effect was obtained through rolling with a 20% reduction.

[0025] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0026] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for improving the anodic electrochemical performance of lead alloys using rare earth elements, characterized in that, Specifically, the following steps are included: S1. Rare earth alloys are smelted in a vacuum furnace, with lanthanum (La), cerium (Ce), and neodymium (Nd) added. Electromagnetic stirring is used to ensure uniform elemental composition. The temperature is controlled at 850℃~1030℃, and the smelting time is 0.5-1 hour. The resulting ingot is cast to obtain the La-Ce-Nd rare earth alloy. S2. A rare earth master alloy is prepared by vacuum furnace melting. The rare earth alloy in S1 is made into rice grains and melted with lead (Pb) to prepare a rare earth master alloy. The alloy concentration is diluted ≤10 times and an antioxidant is added. Mechanical stirring + electromagnetic stirring is used to ensure uniform composition. The temperature is controlled at 500℃~550℃ and the melting time is 0.5h. The Pb-La-Ce-Nd master alloy is obtained by casting ingot. S3. Add 0.5~1.55% rare earth master alloy, 4~6% lead-silver alloy, 0.5~1.51% lead-calcium alloy, and 0.5~1.51% lead-strontium alloy, with the balance being refined lead, to the molten lead in sequence. Add an antioxidant, and use mechanical stirring and electromagnetic stirring to ensure uniform composition. Control the temperature at 450℃~500℃ and the melting time at 0.5h to finally obtain the rare earth lead alloy used for processing anode plates.

2. The method for improving the anodic electrochemical performance of lead alloys using rare earth elements according to claim 1, characterized in that: The components of S1, including lanthanum, cerium, neodymium and antioxidants, include 13-17% lanthanum, 18-22% cerium, 13-17% neodymium and 48-52% antioxidants.

3. The method for improving the anodic electrochemical performance of lead alloys using rare earth elements according to claim 1, characterized in that: The components of S1, including lanthanum, cerium, neodymium and antioxidant, comprise 15% lanthanum, 20% cerium, 15% neodymium and 50% antioxidant.

4. The method for improving the anodic electrochemical performance of lead alloys using rare earth elements according to claim 1, characterized in that: The diluted rare earth master alloy in S2 contains 1.3-1.7% lanthanum, 1.8-2.2% cerium, and 1.3-1.7% neodymium.

5. The method for improving the electrochemical performance of lead alloy anodic electrodes using rare earth elements according to claim 1, characterized in that: The diluted rare earth master alloy in S2 includes 1.5% lanthanum, 2.0% cerium, and 1.5% neodymium.

6. The method for improving the electrochemical performance of lead alloy anodic electrodes using rare earth elements according to claim 1, characterized in that: The alloy components added to the molten lead in S3 are: 5% rare earth intermediate alloy, 1% lead-calcium alloy, 1% lead-strontium alloy, and the balance is lead, with the calcium alloy containing 10% calcium and the lead-strontium alloy containing 10% strontium.

7. A rare earth lead alloy according to any one of claims 1 to 6, characterized in that: It was prepared by a method that utilizes rare earth elements to improve the electrochemical performance of lead alloy anodes.

8. The application of the rare earth lead alloy according to claim 7 in the production of anode plates for zinc electrowinning.

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