Method for preparing ultra-high-purity copper through ultrasonic-assisted electrodeposition and ultra-high-purity copper

Abstract

The invention belongs to the technical field of copper electrolytic refining, and particularly relates to a method for preparing ultra-high-purity copper through ultrasonic-assisted electro-deposition and the ultra-high-purity copper. The method comprises the steps that a cathode and an anode are immersed in electrolyte, electro-deposition is carried out under the ultrasonic-assisted condition, and electrolytic copper is obtained on the cathode; the electrolytic copper is cleaned and dried, and ultra-high-purity copper is obtained; the electrolyte comprises water-soluble copper salt, oxyacid, deionized water and inorganic additives, wherein the inorganic additives comprise hydrochloric acid and hydrogen peroxide. According to the method, an inorganic additive and ultrasonic synergistic strengthening effect is adopted, no organic additive is needed, a diffusion boundary layer is broken through the cavitation effect and the acoustic streaming effect of ultrasonic waves, uniform deposition of copper ions and efficient separation of impurities are achieved, the 7N-grade ultra-high-purity copper is prepared, meanwhile, production energy consumption and cost are considered, and the method is suitable for industrial production. And the high-end requirements of the fields of electronic information, aerospace and the like on the ultrahigh-purity copper are met.

Description

Technical Field

[0001] This invention relates to the field of copper electrolytic refining technology, specifically to a method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition and the ultra-high purity copper. Background Technology

[0002] Ultra-high purity copper possesses excellent electrical conductivity, thermal conductivity, and chemical stability due to its extremely low impurity content, giving it an irreplaceable core position in fields such as semiconductor manufacturing, display panels, photovoltaic energy, aerospace, and high-end testing equipment.

[0003] Currently, the main methods for preparing ultra-high purity copper fall into two categories: pyrometallurgy and hydrometallurgy. Pyrometallurgy, such as zone melting and vacuum distillation, can effectively remove metallic impurities, but its removal efficiency for light element impurities such as carbon, oxygen, and sulfur is relatively low, and it also suffers from high energy consumption and limited production capacity. Electrodeposition, a method within hydrometallurgy, has become the mainstream technology for producing high-purity copper in industry due to its simple operation, controllable cost, and ease of large-scale production. Its core principle is to achieve the directional deposition of copper ions through the reduction reaction at the cathode in an electrolytic cell, thereby separating impurities.

[0004] Existing methods for preparing high-purity copper by electrolysis under ultrasonic action involve adding organic additives to the electrolyte. These organic additives are adsorbed onto the cathode surface to regulate the direction of crystal growth, thus solving the problems of coarse grains and rough surfaces in traditional electrodeposition. However, the organic additives are prone to decomposition or adsorption residues during electrodeposition, inevitably introducing impurities such as carbon and oxygen into the product, which limits further improvement in copper purity. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ultra-high purity copper by ultrasound-assisted electrodeposition, and the resulting ultra-high purity copper. This method uses inorganic additives to prepare 7N-grade ultra-high purity copper. The synergistic effect of ultrasound eliminates the need for organic additives. It utilizes the cavitation and acoustic flow effects of ultrasound to break the diffusion boundary layer, achieving uniform deposition of copper ions while simultaneously refining grains and smoothing the surface. This reduces production energy consumption and costs, meeting the demand for ultra-high purity copper in fields such as electronics, aerospace, and information technology.

[0006] Therefore, a first aspect of the present invention is to provide a method for preparing ultra-high purity copper by ultrasound-assisted electrodeposition, comprising: immersing a cathode and an anode in an electrolyte, performing electrodeposition under ultrasound-assisted conditions, and obtaining electrolytic copper at the cathode; cleaning and drying the electrolytic copper to obtain ultra-high purity copper; the electrolyte comprising water-soluble copper salt, oxyacid, deionized water and inorganic additives, wherein the inorganic additives include hydrogen peroxide and hydrochloric acid.

[0007] This method utilizes inorganic additives to overcome the purity limitations of traditional electrodeposited copper, ultimately producing ultra-high purity copper with a purity of 7N and above. At the same time, it reduces production energy consumption and costs, and the produced ultra-high purity copper meets the needs of fields such as electronics, information technology, and aerospace.

[0008] This method introduces ultrasonic energy into the electrodeposition process using inorganic additives and ultrasound-assisted electrodeposition technology. When ultrasound propagates in the liquid medium, cavitation, acoustic flow, and mechanical vibration effects work synergistically: Firstly, the high-temperature, high-pressure microenvironment generated by cavitation and acoustic flow effectively breaks down the diffusion layer thickness at the cathode interface, enhancing ion mass transfer efficiency. Simultaneously, the microjets generated by the collapse of cavitation bubbles impact the cathode surface, which helps suppress dendrite growth and refine grains. This achieves grain refinement and surface smoothness of the deposited layer without relying on organic additives, reducing impurity contamination introduced by organic additives. Secondly, the mechanical vibration and thermal effects of ultrasound reduce solution viscosity and increase ion migration rates, further optimizing the deposition process. These synergistic effects make the electrodeposition process more efficient and controllable, facilitating the preparation of ultra-high purity copper with satisfactory grain and surface structures.

[0009] In some embodiments of this application, the concentration of hydrogen peroxide in the electrolyte is 0.5 ml / L to 2 ml / L; the concentration of hydrochloric acid is 0.02 g / L to 0.1 g / L. Appropriate concentrations of hydrogen peroxide and hydrochloric acid are beneficial for electrolyte stability, improving the purity of copper to 7N or higher, and can also help suppress the co-deposition of impurities, thus improving the controllability of the electrodeposition process.

[0010] In some embodiments of this application, the concentration of copper ions in the electrolyte is 40 g / L to 90 g / L. This concentration range is beneficial for the stable deposition of copper ions.

[0011] In some embodiments of this application, the water-soluble copper salt includes at least one of copper sulfate or copper nitrate; and / or the oxyacid includes at least one of sulfuric acid or nitric acid. Suitable types of water-soluble copper salt and oxyacids facilitate the controllability of the electrodeposition process and enable synergy with ultrasound-assisted processes.

[0012] In some embodiments of this application, the concentration of oxyacid in the electrolyte is 20 g / L to 100 g / L. A suitable concentration of oxyacid is beneficial for ion migration and can reduce corrosion of the electrodes.

[0013] In some embodiments of this application, the ultrasonic assistance conditions are: ultrasonic frequency 20kHz~100kHz, power density 0.05W / cm². 3 ~0.5W / cm 3 Optionally, the ultrasonic frequency is 20kHz~60kHz, and the power density is 0.1W / cm². 3~0.5W / cm 3 The ultrasound waves can be applied continuously or pulsed. Appropriate ultrasound-assisted conditions can improve deposition efficiency and grain refinement.

[0014] In some embodiments of this application, at least one of the following conditions is met during the electrodeposition process: the current density is 80 A / m. 2 ~250A / m 2 The electrolyte temperature is 15℃~60℃. Electrodeposition parameters within this range can balance deposition rate and deposition quality.

[0015] In some embodiments of this application, drying is performed under vacuum or in an inert atmosphere at a temperature of 50°C to 70°C for 10 to 30 minutes. These drying conditions help reduce copper oxidation or the introduction of impurities during the drying process, which is beneficial for preparing ultra-high purity copper.

[0016] In some embodiments of this application, the cathode includes one of a titanium plate, a coated titanium plate, and a stainless steel plate; optionally, the anode includes a copper plate; optionally, the copper plate contains a copper mass fraction greater than or equal to 99.95%. This electrode selection is beneficial for the electrode to participate stably in the electrodeposition reaction and reduces the impact of electrode impurity dissolution on product purity.

[0017] The second aspect of this invention is to provide an ultra-high purity copper, which is prepared using the ultrasonic-assisted electrodeposition method provided in the first aspect. This ultra-high purity copper achieves a purity of 7N or higher, meeting the high-end demands for ultra-high purity copper in fields such as electronics, aerospace, and more.

[0018] Compared with the prior art, the beneficial effects of the present invention include at least the following: This method enhances the purity of copper to 7N and above by using inorganic additives. Through the synergistic effect of inorganic additives and ultrasound, organic additives are not required. The cavitation and acoustic flow effects of ultrasound break the diffusion boundary layer, achieving uniform deposition of copper ions. This method also balances production energy consumption and cost, meeting the demand for ultra-high purity copper in fields such as electronics, aerospace, and information technology. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 The process flow diagram of the method for preparing ultra-high purity copper by ultrasound-assisted electrodeposition provided by the present invention; Figure 2This is a metallographic image of ultra-high purity copper provided in Embodiment 1 of the present invention; Figure 3 Metallographic diagram of ultra-high purity copper provided for Comparative Example 1; Figure 4 This is a metallographic image of ultra-high purity copper provided in Embodiment 4 of the present invention; Figure 5 This is a metallographic image of ultra-high purity copper provided in Embodiment 5 of the present invention. Detailed Implementation

[0020] Exemplary embodiments of this disclosure will now be described in more detail. It should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0022] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] Electrodeposition technology, as a hydrometallurgical method, has the advantages of strong controllability, low equipment investment and easy scaling, and has shown great potential in the field of ultra-high purity copper preparation. The core principle of preparing high-purity copper by electrolytic refining or electrodeposition is to use an electric field to cause copper ions to be directionally reduced and deposited at the cathode, while impurity elements are suppressed and co-deposited through electrolyte purification and process parameter optimization. The process of preparing high-purity copper plates by electrolytic refining has been industrialized, but in the process of improving the purity of 7N and above and subsequent smelting and processing, the following problems are faced: (1) The contradiction between deposition purity and grain refinement: In the traditional electrolytic refining process, in order to obtain copper plates with smooth surface and refined grains, organic additives such as gelatin and thiourea need to be introduced. However, these organic additives are very likely to cause impurities such as carbon, oxygen and sulfur to be encapsulated in the copper deposition layer, which will then form inclusion defects in subsequent smelting and processing, which is not conducive to further improvement of copper purity and product yield. (2) Limited mass transfer efficiency and deposition rate: An excessively thick diffusion layer at the cathode interface will cause significant concentration polarization, which is not conducive to the deposition rate of copper ions and is also prone to induce co-deposition of impurity ions, further affecting the purity of the product. (3) Poor microstructure quality of the deposition layer: Copper deposition layers are prone to problems such as coarse and uneven grains, high internal stress, and high defect density (such as pores and dendrites). These microstructure defects will seriously affect the mechanical properties (such as fatigue resistance), electrical performance consistency and long-term reliability of ultra-high purity copper.

[0025] 7N is the core grade standard for measuring copper purity, defined as a copper mass fraction of not less than 99.99999%. That is, the total mass fraction of impurities (non-gaseous elements) is not higher than 0.00001%. In other words, gaseous / gaseous elements such as C, N, O, H, and Cl are not included in the total impurity statistics.

[0026] Based on this, the first aspect, such as Figure 1 As shown, the present invention provides a method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition, comprising: immersing the cathode and anode in an electrolyte, performing electrodeposition under ultrasonic assistance, and obtaining electrolytic copper at the cathode; cleaning and drying the electrolytic copper to obtain ultra-high purity copper; the electrolyte comprises water-soluble copper salt, oxyacid, deionized water and inorganic additives, the inorganic additives including hydrochloric acid and hydrogen peroxide.

[0027] In some embodiments, the method for preparing ultra-high purity copper by ultrasound-assisted electrodeposition may include electrolyte preparation: using deionized water as a solvent, dissolving a water-soluble copper salt (such as at least one of copper sulfate and copper nitrate) and an oxyacid (at least one of sulfuric acid or nitric acid), and adding HCl and hydrogen peroxide. The prepared electrolyte is filtered through a filter cartridge to ensure initial cleanliness.

[0028] In some embodiments, the concentration of hydrogen peroxide in the electrolyte is 0.5 ml / L to 2 ml / L. For example, the concentration of hydrogen peroxide can be 0.5-0.5 ml / L, 0.6 ml / L, 0.7 ml / L, 0.8 ml / L, 0.9 ml / L, 1 ml / L, 1.1 ml / L, 1.2 ml / L, 1.3 ml / L, 1.4 ml / L, 1.5 ml / L, 1.6 ml / L, 1.7 ml / L, 1.8 ml / L, 1.9 ml / L, 2 ml / L, or a range consisting of any two of these values, or other values ​​selected from the above range.

[0029] In some embodiments, the concentration of hydrochloric acid in the electrolyte is 0.02 g / L to 0.1 g / L. For example, the concentration of hydrochloric acid can be 0.02 g / L, 0.03 g / L, 0.04 g / L, 0.05 g / L, 0.06 g / L, 0.07 g / L, 0.08 g / L, 0.09 g / L, 0.1 g / L, or a range consisting of any two of these values, or other values ​​selected from the above range.

[0030] In the electrolyte, the concentrations of hydrogen peroxide and hydrochloric acid are within a reasonable range. Hydrochloric acid helps to directionally shield heavy metal impurities, reduce the risk of co-deposition, effectively inhibit dendrite growth, assist in the smoothness of the final product surface, and reduce electrode corrosion and impurity residue. Hydrogen peroxide can oxidize low-valence impurity ions, which helps to block their co-deposition pathways, is beneficial for the deposition of copper with a purity of 7N and above, and can also stabilize Cu. 2+ Concentration increases the density of the deposited layer, balancing oxidation efficiency and cost. The two work synergistically to replace the function of organic additives, helping to reduce impurity contamination and deposition defects.

[0031] In some embodiments, the concentration of copper ions in the electrolyte is 40 g / L to 90 g / L. For example, the concentration of copper ions in the electrolyte can be 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, or a range of any two values ​​therein, or other values ​​selected from the above range. A copper ion concentration of 40 g / L to 90 g / L satisfies the continuous demand for copper ions from the cathode under ultrasonic acceleration, while reducing the problems of increased electrolyte viscosity, copper salt precipitation, and impurity enrichment caused by high concentrations, thus maintaining system stability. At the same time, this concentration range can balance the formation and growth rate of crystal nuclei, and combined with the ultrasonic refining effect, ensure that the grain size of the deposited layer meets the requirements.

[0032] In some embodiments, the concentration of the oxyacid in the electrolyte is 20 g / L to 100 g / L. For example, the concentration of the oxyacid in the electrolyte can be 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, or a range consisting of any two of these values, or other values ​​selected from the above range. A concentration of 20 g / L to 100 g / L of oxyacid in the electrolyte can maintain a strongly acidic environment with a pH value of 1.0 to 2.0, effectively inhibiting Cu. 2+ Hydrolysis generates Cu(OH)₂ precipitate (avoiding the introduction of oxygen impurities), which in turn improves the conductivity of the electrolyte and reduces cell voltage to decrease energy consumption; simultaneously, this concentration range can be controlled by H₂O. + Competitive adsorption inhibits Fe 3+ Ni 2+ The co-deposition of impurities, combined with the complexation of heavy metals by HCl and the oxidation of low-valence impurities by hydrogen peroxide, is beneficial to achieving a product purity of 7N and above. It can also effectively reduce the problem of insufficient mass transfer efficiency caused by low concentration, which is conducive to the refinement of the deposited layer grains and the improvement of density.

[0033] In some embodiments, the ultrasonic assistance conditions are: ultrasonic frequency 20kHz~100kHz, power density 0.05W / cm². 3 ~0.5W / cm 3 Optionally, the ultrasonic frequency is 20kHz~60kHz, and the power density is 0.1W / cm². 3 ~0.5W / cm 3 The ultrasound can be applied continuously or pulsed. For example, the ultrasound-assisted conditions can be ultrasound frequencies of 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, 90kHz, 100kHz, or any two of these values, or other values ​​selected from the above ranges. The power density can be, for example, 0.05W / cm³, 0.1W / cm³, 0.2W / cm³, 0.3W / cm³, 0.4W / cm³, 0.5W / cm³, or any two of these values, or other values ​​selected from the above ranges. This condition is beneficial for controlling the acoustic cavitation, acoustic flow, and mechanical vibration effects of the ultrasound. Matching the frequency and power further enhances the synergistic effect to improve mass transfer efficiency and grain refinement. Continuous application ensures stable deposition, while pulsed application allows for flexible adjustment of energy input. Ultimately, this facilitates breaking the cathode diffusion layer and effectively suppressing impurity co-deposition and dendrite growth without organic additives.

[0034] In some embodiments of this application, the cathode includes one of a titanium plate, a titanium-plated plate, and a stainless steel plate; optionally, the anode includes a copper plate; optionally, the copper plate contains a copper mass fraction greater than or equal to 99.95%.

[0035] Electrode pretreatment and installation: Before use, the electrode plates must be soaked in dilute sulfuric acid to remove surface oxides and stains. The cathode and anode are placed alternately in parallel within the electrolytic cell, with the electrode spacing controlled between 50mm and 80mm. Those skilled in the art can adjust the number and spacing of the electrodes according to actual needs.

[0036] In some embodiments of this application, the specific ultrasound-assisted electrodeposition process can be as follows: Immerse the pretreated cathode and anode in the electrolyte; start the system: turn on the electrolyte purification and circulation pump to circulate the electrolyte at a certain flow rate (e.g., 0.006 L / min ~ 0.05 L / min); apply ultrasound: turn on the ultrasound generator, set a specific frequency and power density, the mode can be continuous or pulsed; control the electrolysis parameters, and perform electrodeposition: apply direct current, controlling the current density at 80 A / m. 2 ~250A / m 2 The electrolyte temperature is maintained between 15℃ and 60℃. Process monitoring: Record data parameters such as temperature to maintain process stability.

[0037] In some embodiments, at least one of the following conditions is met during the electrodeposition process: the current density is 80 A / m 2 ~250A / m 2 The electrolyte temperature is 15℃~60℃. The current density is, for example, 80A / m³. 2 90A / m 2 100A / m 2 130A / m 2 150A / m 2 180A / m 2 200A / m 2 250A / m 2 The values ​​may be any two of these ranges, or other values ​​selected from the aforementioned ranges. The electrolyte temperature may be, for example, 15°C, 20°C, 30°C, 40°C, 50°C, 60°C, or any two of these ranges, or other values ​​selected from the aforementioned ranges. This parameter design can synergize with the ultrasonic effect and the electrolyte system; this current density range is beneficial for balancing rate and purity; this temperature range can maintain electrolyte stability, taking into account both the structure and production efficiency of ultra-high purity copper.

[0038] In some embodiments, the electrolytic copper deposited on the cathode is periodically removed. It is then washed sequentially with deionized water-dilute acid-deionized water to remove surface deposits. Vacuum drying or inert atmosphere drying at a low temperature of 50°C~70°C for 10-30 minutes is performed to prevent copper oxidation. The resulting ultra-high purity copper is then vacuum-packed for storage or use.

[0039] In some embodiments, the drying temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, or a range of any two of these values, or other values ​​selected from the above range. The drying time can be, for example, 10 min, 15 min, 20 min, 25 min, 30 min, or a range of any two of these values, or other values ​​selected from the above range. These drying parameters help reduce the oxidation reaction of ultra-high purity copper during the drying process, balancing drying efficiency with the performance of ultra-high purity copper.

[0040] Secondly, the present invention provides an ultra-high purity copper, which is prepared by the ultrasonic-assisted electrodeposition method provided in the first aspect.

[0041] Example 1 Electrolyte preparation: Dissolve copper sulfate pentahydrate (CuSO4·5H2O, purity ≥99.99%) in high-purity deionized water with a resistivity of 18.2 MΩ·cm to prepare a solution with a copper ion concentration of 50 g / L. Add high-purity sulfuric acid (purity ≥99.99%) to make the sulfuric acid concentration in the solution 80 g / L. Add HCl (concentration 0.1 g / L) and hydrogen peroxide (concentration 1 ml / L), mix well, and filter through a 0.22 μm filter to obtain a purified electrolyte.

[0042] Electrodeposition process: A titanium plate, soaked in dilute sulfuric acid and mechanically polished, was used as the cathode, and a copper plate (Cu ≥ 99.95%) was used as the anode, with an electrode spacing of 70 mm. The temperature of the purified electrolyte was controlled at 30℃. The ultrasonic generator was turned on, with a frequency of 50 kHz and a power density of 0.2 W / cm³. 3 (Continuous mode). After the sound field stabilizes, apply a current density of 150 A / m. 2 Electrodeposition was performed using direct current for 96 hours.

[0043] Post-processing: After electrodeposition, the cathode plate is removed and immediately cleaned and dried using a cycle of high-purity deionized water, dilute sulfuric acid solution, and high-purity deionized water to obtain ultra-high purity copper, denoted as ultra-high purity copper-1.

[0044] The ultra-high purity copper was characterized, and the results are shown in Table 1.

[0045] Table 1. Test results of ultra-high purity copper-1

[0046] Table 1 shows the results of glow discharge mass spectrometry (GDMS) analysis. The copper purity (excluding C and O elements) reached 99.99999% (7N level). Furthermore, the carbon impurity content was less than 1 ppm, the oxygen impurity content was less than 2 ppm, and the sulfur impurity content was less than the detection limit of 0.005 ppm. Metallurgical microscopy was used to characterize the grain structure of copper plates prepared by ultrasonic-assisted electrodeposition and those prepared without ultrasonic assistance. The results showed that... Figure 2 As shown, the copper plate prepared under ultrasonic assistance has a small grain size and no obvious coarse grains or defects.

[0047] Comparative Example 1 Compared to Example 1, the only difference is that there is no ultrasonic assistance during the preparation process.

[0048] GDMS analysis results: purity is 99.99999% (7N level). Grain structure morphology characterization analysis is as follows: Figure 3 As shown, the grain size is significantly larger and the grain distribution is uneven, with local grain agglomeration and large size differences.

[0049] Comparative Example 2 Compared with Example 1, the only difference is that hydrogen peroxide is not used in the preparation process, and 5-amino-1H tetrazolium is used at a concentration of 0.2 g / L.

[0050] The electrolytic copper plate of Comparative Example 2 has a relatively smooth surface. According to GDMS analysis, its purity is 99.997% (not reaching the 7N level), carbon content is 8 ppm, oxygen content is 5 ppm, and sulfur content is 1.2 ppm.

[0051] Example 2 Compared with Example 1, the only difference is that the hydrochloric acid concentration is 0.05 g / L, denoted as ultra-high purity copper-2.

[0052] Table 2. Test results of ultra-high purity copper-2

[0053] As can be seen, the purity of the electrolytic copper plate in Example 2 was 99.99999% (7N level) according to GDMS analysis.

[0054] Example 3 Compared to Example 1, the only difference is the hydrochloric acid concentration, which is 0.02 g / L. This is designated as ultra-high purity copper-3. The electrolytic copper plate of Example 3 has a smooth and dense surface with fine grains. GDMS analysis showed that the purity of this ultra-high purity copper-3 was 99.99999% (7N level). The test results are as follows: Table 3. Test results of ultra-high purity copper-3

[0055] Example 4 Compared to Example 1, the only difference is that the hydrochloric acid concentration is 0.08 g / L. This is denoted as Ultra-High Purity Copper-4.

[0056] The electrolytic copper plate in Example 4 has a smooth and dense surface with fine grains. The grain structure morphology characterization analysis is as follows: Figure 4 As shown, the GDMS analysis results for ultra-high purity copper-4 indicate a purity of 99.99999% (7N level). The test results are as follows: Table 4. Test results of ultra-high purity copper-4

[0057] Example 5 Compared to Example 1, the only difference is that the hydrogen peroxide concentration is 1.2 ml / L. This is denoted as Ultra-High Purity Copper-5.

[0058] The electrolytic copper plate in Example 5 has a smooth and dense surface with fine grains. The grain structure morphology characterization analysis is as follows: Figure 5 As shown, GDMS analysis revealed that the purity of ultra-high purity copper-5 was 99.99999% (7N level). The test results are as follows: Table 5. Test results of ultra-high purity copper-5

[0059] Example 6 Compared to Example 1, the only difference is that the hydrogen peroxide concentration is 2 ml / L. This is denoted as Ultra-High Purity Copper-6.

[0060] The electrolytic copper plate in Example 6 has a smooth and dense surface, and GDMS analysis shows it to be ultra-high purity copper-6. The purity is 99.99999% (7N level), and the test results are as follows: Table 6. Test results of ultra-high purity copper-6

[0061] Example 7 Compared to Example 1, the only difference is that copper sulfate (purity ≥ 99.99%) was dissolved in high-purity deionized water with a resistivity of 18.2 MΩ·cm to prepare a solution with a copper ion concentration of 50 g / L. This solution is designated as Ultra-High Purity Copper-7.

[0062] The electrolytic copper plate of Example 7 has a smooth and dense surface. GDMS analysis showed that the purity of ultra-high purity copper-7 was 99.99999% (7N level). The test results are as follows: Table 7 Test results of ultra-high purity copper-7

[0063] Example 8 Compared to Example 1, the only difference is that copper nitrate and copper sulfate (purity ≥99.99%) were dissolved in high-purity deionized water with a resistivity of 18.2 MΩ·cm to prepare a solution with a copper ion concentration of 50 g / L. This solution is designated as Ultra-High Purity Copper-8.

[0064] The electrolytic copper plate of Example 8 has a smooth and dense surface. GDMS analysis showed that the purity of ultra-high purity copper-8 was 99.99999% (7N level). The test results are as follows: Table 8 Test results of ultra-high purity copper-8

[0065] Example 9 Compared to Example 1, the only difference is the addition of high-purity nitric acid (purity ≥99.99%), resulting in a nitric acid concentration of 80 g / L in the solution. This is designated as Ultra-High Purity Copper-9.

[0066] The electrolytic copper plate of Example 9 has a smooth and dense surface. GDMS analysis showed that the purity of this ultra-high purity copper-9 was 99.99999% (7N level). The test results are as follows: Table 9. Test results of ultra-high purity copper-9

[0067] Example 10 Compared to Example 1, the only difference is the addition of high-purity sulfuric acid and high-purity nitric acid (purity ≥99.99%), resulting in a high-purity sulfuric acid concentration of 10 g / L and a nitric acid concentration of 20 g / L in the solution. This is designated as Ultra-High Purity Copper-10.

[0068] The electrolytic copper plate of Example 10 has a smooth and dense surface. GDMS testing results show that the purity of this ultra-high purity copper-10 is 99.99999% (7N level), as detailed below: Table 10 Test Results of Ultra-High Purity Copper-10

[0069] In summary, comparing Examples 1-10 with Comparative Examples 1 and 2, it is evident that the ultrasonic assistance introduced in the preparation method of this application effectively refines the grains of ultra-high purity copper, while the inorganic additives help improve the overall purity of the ultra-high purity copper. Compared to preparation methods that add organic additives, the copper product obtained in this application has a significant advantage in copper content. It is clear that the synergistic introduction of ultrasound and inorganic additives can effectively refine the grains of electrolytic copper, improving its surface quality and density. The preparation method provided in this application breaks through the purity bottleneck of traditional processes, and can produce ultra-high purity copper with a purity of 7N and above.

[0070] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition, characterized in that, The application relates to a method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition. The cathode and the anode are immersed in an electrolyte, and electrodeposition is carried out under ultrasonic assistance, and electrolytic copper is obtained at the cathode; The electrolytic copper is cleaned and dried to obtain ultra-high purity copper. The electrolyte comprises a water-soluble copper salt, an oxygen-containing acid, deionized water and an inorganic additive, and the inorganic additive comprises hydrochloric acid and hydrogen peroxide.

2. The method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition according to claim 1, characterized in that, The concentration of the hydrogen peroxide in the electrolyte is 0.5-2 ml / L, and the concentration of the hydrochloric acid is 0.02-0.1 g / L.

3. The method of claim 1, wherein the ultrasonic-assisted electrodeposition for preparing ultra-high purity copper is characterized by, The concentration of copper ions in the electrolyte is 40-90 g / L.

4. The method of claim 1, wherein the ultrasonic-assisted electrodeposition of ultra-high purity copper is characterized by, The water-soluble copper salt comprises at least one of copper sulfate or copper nitrate; and / or The oxygen-containing acid comprises at least one of sulfuric acid or nitric acid.

5. The method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition according to claim 1 or 4, characterized in that, The concentration of the oxygen-containing acid in the electrolyte is 20-100 g / L.

6. The method of claim 1, wherein the ultrasonic-assisted electrodeposition of ultra-high purity copper is characterized by, The ultrasonic-assisted conditions: ultrasonic frequency 20 kHz~100 kHz, power density 0.05 W / cm 3 ~0.5 W / cm 3 ; and / or The ultrasonic wave is applied in a continuous mode or a pulse mode.

7. The method of claim 1, wherein the ultrasonic-assisted electrodeposition of ultra-high purity copper is characterized by, At least one of the following conditions is met during the electrodeposition process: Current density 80 A / m 2 ~250 A / m 2 ; The temperature of the electrolyte is 15-60 DEG C.

8. The method of claim 1, wherein the ultrasonic-assisted electrodeposition of ultra-high purity copper is characterized by, The drying is vacuum drying or drying in an inert atmosphere, the drying temperature is 50-70 DEG C, and the drying time is 10-30 min.

9. The method of claim 1, wherein the ultrasonic-assisted electrodeposition of ultra-high purity copper is characterized by, The cathode comprises one of a titanium plate, a plated titanium plate and a stainless steel plate; and / or The anode comprises a copper plate; and / or The mass fraction of copper in the copper plate is greater than or equal to 99.95%.

10. An ultra-high purity copper characterized in that, The ultra-high purity copper is prepared by the method for preparing ultra-high purity copper by ultrasonic-assisted electrodeposition according to any one of claims 1-9.

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