Cathode, electrolysis device and preparation method of ultra-high-purity copper of electrolysis device

Abstract

The invention relates to the technical field of electro-deposition, and discloses a cathode, an electrolysis device and a preparation method of ultra-high-purity copper. The electrolysis device comprises an electrolysis unit (100), wherein the electrolysis unit (100) comprises an electrolysis bath main body (1), an anode (2), a cathode (3) and an anode chamber (4); the anodes (2) and the cathodes (3) are alternately arranged in an inner cavity of the electrolytic bath main body (1) along the length direction of the electrolytic bath main body (1); the anode (2) is arranged in the anode chamber (4); the electrolysis unit (100) further comprises a first ultrasonic probe (5) which is installed on the upper portion of the cathode (3) in an embedded and sealed mode. According to the electrolysis device provided by the invention, the first ultrasonic probe is mounted at the upper part of the cathode in an embedded sealing manner, so that the purity and uniformity of an electrolysis product can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of electrolysis equipment technology, and in particular to a cathode, an electrolysis device, and a method for preparing ultra-high purity copper. Background Technology

[0002] Ultra-high purity copper (typically referring to copper with a purity ≥ 99.9999 wt%, i.e., 6N and above) is a core material in cutting-edge fields such as electronic information technology, aerospace, and high-energy physics. It is primarily used in the manufacture of interconnects for high-performance computing chips, sputtering targets, and internal cavities of particle accelerators. These applications place extremely stringent requirements on the purity, grain structure, defect density, and electrical properties of ultra-high purity copper.

[0003] Currently, the most common method for industrial production of high-purity copper is electrolytic refining. In industrial production, electrolytic refining essentially utilizes the redox reaction in an electrolytic cell to transfer pure copper from the crude copper (anode) to the cathode, while simultaneously separating impurities. Specifically, the copper at the anode preferentially loses electrons and oxidizes to dissolve into Cu. 2+ It enters the electrolyte. Simultaneously, impurities more reactive than Cu in the crude copper (such as Ag, Se, Te, and Pb) dissolve, while impurities less reactive than Cu (such as Ag, Au, and Pt) do not dissolve and settle at the bottom of the anode as "anode mud." Cu in the electrolyte... 2+ At the cathode (pure copper electrode), electrons are gained, reducing the copper to pure copper, which then adheres to the cathode surface. Impurities less reactive than Cu do not deposit at the cathode under specific electrolysis conditions but remain in the electrolyte, thus achieving separation from Cu.

[0004] Electrolytic refining is generally carried out in an electrolytic cell, which is an electrochemical device that uses electrical energy to drive non-spontaneous redox reactions to achieve material transformation or purification. To improve mass transfer efficiency and enhance reaction rates, ultrasonic devices can be installed in the electrolytic cell. However, the following drawbacks also exist: 1) External ultrasonic devices (set on the outer wall of the electrolytic cell) require the ultrasound to penetrate the cell wall, resulting in significant energy loss (attenuation often exceeds 30%). 2) Immersion ultrasonic devices (set on the inner wall of the electrolytic cell and submerged in the electrolyte during use) exhibit a strong "near-field effect," creating an interference zone with extremely uneven energy distribution near the probe (the near-field region, typically 1-2 times the probe diameter). This leads to significant differences in the ultrasonic energy density received by the cathode plates at different locations within the electrolytic cell, affecting the purity and uniformity of the product. 3) The high-frequency mechanical vibrations of ultrasound can directly impact critical structures of the electrolytic cell, causing component wear or failure. For example, diaphragm bags made of polyester or polypropylene are prone to fiber breakage, hole tearing, or overall embrittlement and damage under the continuous microscopic impact generated by strong ultrasonic cavitation, resulting in a large leakage of anode mud. Summary of the Invention

[0005] To address at least one of the aforementioned problems in the prior art, this invention provides a cathode, an electrolysis apparatus, and a method for preparing ultra-high purity copper. The electrolysis apparatus provided in this invention, by embedding and sealing a first ultrasonic probe in the upper part of the cathode, can significantly improve the purity and uniformity of the electrolytic product, and is particularly suitable for producing ultra-high purity copper.

[0006] To address the aforementioned problems, the present invention provides an electrolysis apparatus, wherein the electrolysis apparatus includes an electrolysis unit 100, the electrolysis unit 100 including an electrolysis cell body 1, an anode 2, a cathode 3, and an anode chamber 4; wherein, along the length direction of the electrolysis cell body 1, the anode 2 and the cathode 3 are alternately arranged in the inner cavity of the electrolysis cell body 1; the anode 2 is disposed in the anode chamber 4; the electrolysis unit further includes a first ultrasonic probe 5; wherein, along the height direction of the electrolysis cell body 1, the first ultrasonic probe 5 is embedded and sealed in the upper part of the cathode 3.

[0007] A second aspect of the present invention provides a cathode in which an ultrasonic probe is embedded and sealed at one end; when the cathode is in use, the ultrasonic probe is positioned above the electrolyte.

[0008] A third aspect of the present invention provides a method for preparing ultra-high purity copper, wherein the preparation method is carried out in the electrolysis apparatus described in the first aspect of the present invention.

[0009] Compared with the prior art, the present invention has the following beneficial technical effects: 1) The electrolysis device provided by the present invention places the first ultrasonic probe above the cathode, which can ensure that the first ultrasonic probe is above the electrolyte during use. This can effectively solve the problem of huge differences in ultrasonic energy density at different positions of the electrolysis cell body caused by the near-field effect. 2) The electrolysis device provided by this invention adopts an embedded sealed installation method. There is no traditional installation gap between the first ultrasonic probe and the cathode. The vibration caused by the ultrasonic waves emitted by the first ultrasonic probe can be directly transmitted to the cathode through solid contact, driving the cathode to generate synchronous micro-amplitude high-frequency vibration. This can effectively solve the problem of severe attenuation of ultrasonic energy caused by the air-electrolyte transmission path in non-immersion ultrasonic probes. Moreover, appropriate vibration of the cathode can destroy the diffusion boundary layer on the cathode surface, greatly accelerate the transfer rate of reactant ions, promote the rapid desorption of products, reduce side reactions caused by concentration polarization (such as hydrogen evolution reaction), and ultimately improve the current efficiency and the purity and uniformity of the target product. 3) The electrolysis device provided by the present invention has an oxide film on the cathode. The oxide film has the advantages of being hard, smooth and resistant to cavitation corrosion, which can significantly reduce the damage caused by ultrasonic waves to the cathode. 4) The electrolysis device provided by the present invention places the anode in a double-layer diaphragm bag made of acid-resistant and cavitation-resistant fiber. The double-layer diaphragm bag is not easily damaged under ultrasound and is more durable. It can not only effectively reduce the mechanical loss of the electrolysis device under ultrasound, but also better prevent the diffusion of anode mud and collect anode mud more efficiently, which helps to improve the purity of electrolysis products (such as ultra-high purity copper). 5) The electrolysis device provided by the present invention can intelligently adjust and match the optimal current parameters, ultrasonic parameters and fluid parameters during the production process through the control unit, realizing a leap from experience-based control to precise intelligent control of the entire production process, thereby ensuring the consistency, high quality and reproducibility of electrolyzed products; 6) The present invention provides a method for preparing ultra-high purity copper, which is simple to operate, produces products with high purity and uniformity, and is suitable for industrial application. Attached Figure Description

[0010] 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 scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the structure of an electrolysis device provided in this invention; Figure 2 This is a metallographic microscope image of the ultra-high purity copper prepared in Example 1 of the present invention.

[0011] Explanation of reference numerals in the attached figures 100, Electrolysis Unit 200, Circulating Filter Unit 300, Control Unit 1. Electrolytic cell body 2. Anode 3. Cathode 4. Anode chamber 5. First ultrasonic probe 6. Diaphragm bag 7. Second ultrasonic probe 8. Ultrasonic generator 9. Liquid inlet 10. Liquid outlet 11. Imported baffle 12. Exit baffle 13. Circulating pump 14. Filter Detailed Implementation The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] A first aspect of the present invention provides an electrolysis apparatus, wherein the electrolysis apparatus includes an electrolysis unit 100, the electrolysis unit 100 including an electrolysis cell body 1, an anode 2, a cathode 3 and an anode chamber 4; wherein, along the length direction of the electrolysis cell body 1, the anode 2 and the cathode 3 are alternately arranged in the inner cavity of the electrolysis cell body 1; the anode 2 is disposed in the anode chamber 4; The electrolysis unit further includes a first ultrasonic probe 5; wherein, along the height direction of the electrolysis cell body 1, the first ultrasonic probe 5 is embedded and sealed in the upper part of the cathode 3, such as... Figure 1 As shown.

[0013] In this invention, the first ultrasonic probe is positioned above the cathode, ensuring it remains above the electrolyte during use. This effectively addresses the significant differences in ultrasonic energy density across different locations within the electrolytic cell caused by near-field effects. The embedded, sealed installation eliminates the traditional installation gap between the first ultrasonic probe and the cathode. The vibrations emitted by the probe are directly transmitted to the cathode via solid contact, driving synchronous, low-amplitude, high-frequency vibrations. This effectively solves the problem of severe ultrasonic energy attenuation caused by the air-electrolyte transmission path in non-immersion ultrasonic probes. Furthermore, appropriate cathode vibration disrupts the diffusion boundary layer on the cathode surface, significantly accelerating the transfer rate of reactant ions and promoting rapid product desorption. This reduces side reactions caused by concentration polarization (such as hydrogen evolution), ultimately improving current efficiency and the purity and uniformity of the target product.

[0014] In some embodiments of the present invention, the embedded sealing installation adopts an embedded sealing installation structure; the embedded sealing installation structure includes an installation groove, sealant and a cover plate; wherein, the installation groove is disposed on the upper part of the cathode 3, the first ultrasonic probe 5 is installed in the installation groove, the installation groove is filled with sealant, and the cover plate is disposed on the installation groove and sealed to the cathode 3 by welding.

[0015] In this invention, a mounting groove can be first excavated in the upper part of the cathode. After the first ultrasonic probe is placed in the groove, sealant (e.g., high-purity, high-insulation, high-elasticity silicone gel or polyurethane) is added for filling. After the sealant cures, an elastic buffer layer is formed in the mounting groove, which can both fix the first ultrasonic probe and absorb vibration stress. Then, a cover plate (preferably a titanium cover plate) is placed on the mounting groove, and the cover plate and the cathode are sealed with a laser weld.

[0016] In some embodiments of the present invention, the number of first ultrasonic probes 5 disposed on a single cathode 3 is 2-20, preferably 6-10. Preferably, the first ultrasonic probes 5 are evenly distributed on the upper part of the cathode. The cathode is plate-shaped and can be disposed on one side of the cathode or on both sides of the cathode, preferably symmetrically disposed on both sides of the cathode.

[0017] In some embodiments of the present invention, the first ultrasonic probe is a multi-frequency ultrasonic probe, wherein the ultrasonic frequency of the multi-frequency ultrasonic probe is 40kHz-100kHz, which can be divided into ultra-high frequency (80kHz-100kHz), high frequency (60kHz-80kHz), and medium frequency (40kHz-60kHz). Among them, 80kHz is classified as ultra-high frequency, and 60kHz is classified as high frequency.

[0018] In this invention, the electrodeposition reaction in the electrolysis apparatus generally includes three stages: the initial nucleation stage, the high-speed growth stage, and the surface finishing stage. The first ultrasonic probe can provide ultrasonic waves of different frequencies for different stages. During the initial nucleation stage, ultra-high frequency ultrasonic waves of 80kHz-100kHz are provided to promote uniform nucleation and obtain a dense initial layer. During the high-speed growth stage, mid-frequency ultrasonic waves of 40kHz-60kHz are provided to strongly disrupt the diffusion layer, suppress anode slime, and facilitate high-speed deposition. During the surface finishing stage, high-frequency ultrasonic waves of 60kHz-80kHz are provided to offer gentle cavitation and acoustic flow effects. The cavitation effect is responsible for decontamination and smoothing, while the acoustic flow effect is responsible for optimizing the structure, ultimately achieving a smooth, bright, and dense surface on the electrolyzed product.

[0019] In some embodiments of the present invention, the electrolytic cell body 1 includes an outer shell and an inner liner, wherein the material of the outer shell is selected from one or more of stainless steel, titanium alloy, nickel alloy, carbon steel, and polyolefin plastics (e.g., polypropylene, polyethylene, polyvinyl chloride); the material of the inner liner is selected from one or more of polytetrafluoroethylene (PTFE), polypropylene fiber, polyethylene fiber, and polyvinylidene fluoride fiber, preferably polytetrafluoroethylene.

[0020] In this invention, the liner refers to a protective material layer laid inside the outer shell that comes into direct contact with the electrolyte. The liner is made of a material with excellent corrosion resistance and good insulation properties, effectively preventing electrolyte leakage and avoiding equipment failures or environmental risks caused by corrosion of the electrolytic cell itself, thus ensuring stable electrodeposition. Preferably, the effective volume of the electrolytic cell body can be 400L-600L.

[0021] In some embodiments of the present invention, the anode 2 is selected from a copper plate, wherein the purity of copper in the copper plate is ≥99.95wt%.

[0022] In some embodiments of the present invention, the cathode 3 is selected from a titanium plate, and an oxide film is disposed on the titanium plate; wherein, the material of the oxide film is selected from one or more of titanium dioxide, tungsten oxide, and titanium-tungsten composite oxide, and the thickness of the oxide film is preferably in the range of 3µm-10µm.

[0023] In this invention, when ultrasound propagates in the electrolyte, changes in local pressure lead to the formation of microbubbles. These bubbles continuously expand and contract under the influence of ultrasound. When the sound pressure reaches a certain value, the bubbles rapidly expand and generate strong shock waves upon closure; this phenomenon is called cavitation. The shock waves generated by ultrasonic cavitation may cause physical damage to the titanium plate surface, such as microcracks and peeling. These defects not only reduce the surface quality of the titanium plate but may also become corrosion initiation points, accelerating the corrosion process. An oxide film is deposited on the cathode plate. This oxide film has the advantages of being hard, smooth, and resistant to cavitation corrosion, which can significantly reduce the damage caused by ultrasound to the titanium plate, effectively resist electrolyte erosion, and ensure the purity and stability of the deposition process. Preferably, the oxide film can be prepared by surface micro-arc oxidation treatment.

[0024] In some embodiments of the present invention, the first and last anodes 2 are both located along the length of the electrolytic cell body 1. In this invention, the anodes and cathodes are arranged alternately in the order of "anode-cathode-anode-cathode," starting with and ending with an anode; that is, the first and last anode are both anodes. The installation distance between adjacent anodes and cathodes is 80mm-100mm.

[0025] In some embodiments of the present invention, the anode chamber 4 is not specifically limited, and any conventional anode chamber in the art can be used in the present invention.

[0026] In some embodiments of the present invention, the electrolysis unit 100 further includes a diaphragm bag 6, wherein the anode 2 is disposed in the diaphragm bag 6, and the diaphragm bag 6 is disposed in the anode chamber 4.

[0027] In some embodiments of the present invention, the diaphragm bag 6 is a double-layer diaphragm bag, and the material is selected from one or more of polytetrafluoroethylene fiber, polypropylene fiber, polyethylene fiber, and polyvinylidene fluoride fiber, and the mesh size of its filter layer is ≤50µm.

[0028] In this invention, the diaphragm bag is double-layered and made of acid-resistant and cavitation-resistant fiber material, which is not easily damaged under ultrasound and is more durable. It can not only effectively reduce the mechanical loss of the electrolysis device under ultrasound, but also better prevent the diffusion of anode mud and collect anode mud more efficiently, which helps to improve the purity of electrolysis products (such as ultra-high purity copper).

[0029] In some embodiments of the present invention, the electrolysis unit 100 further includes a second ultrasonic probe 7, wherein the second ultrasonic probe 7 is disposed on the inner wall of the anode chamber 4.

[0030] In this invention, the second ultrasonic probe, positioned on the inner wall of the anode chamber, is located within the electrolyte. The ultrasonic waves emitted by the second probe can dislodge anode sludge from the anode surface, forcing it to settle and collect in a diaphragm bag, thus preventing the sludge from diffusing to the cathode and solving the anode sludge contamination problem. Therefore, the electrolysis device of this invention can be used to produce electrolytic products with high purity and good uniformity. This invention does not impose any special limitations on the placement of the second ultrasonic probe on the inner wall of the anode chamber; it can be external. To prevent the electrolyte from corroding the second ultrasonic probe, a sealing layer formed by sealant can be applied to it.

[0031] In some embodiments of the present invention, the number of second ultrasonic probes 7 disposed in a single anode chamber 4 is 2-30, preferably 10-20. Preferably, the second ultrasonic probes 7 are uniformly distributed on the inner wall of the anode chamber. For example, they can be symmetrically distributed on the two side walls of the anode chamber 4.

[0032] In some embodiments of the present invention, the transducers in the first ultrasonic probe 5 and the second ultrasonic probe 7 are each selected from one or more of the following: miniature piezoelectric ceramic transducers, electromagnetic ultrasonic transducers, polymer piezoelectric transducers, and capacitive ultrasonic transducers, preferably miniature piezoelectric ceramic transducers.

[0033] In some embodiments of the present invention, the electrolysis unit 100 further includes an ultrasonic generator 8, wherein the ultrasonic generator 8 is connected to the first ultrasonic probe 5 and the second ultrasonic probe 7 respectively.

[0034] In this invention, multiple first and second ultrasonic probes are provided, and each first and second ultrasonic probe can be independently controlled by an ultrasonic generator.

[0035] In some embodiments of the present invention, the electrolysis unit 100 further includes an inlet 9, an outlet 10, an inlet baffle 11, and an outlet baffle 12; along the length direction of the electrolytic cell body 1, the inlet 9 and the outlet 10 are respectively disposed on two opposite sides of the electrolytic cell body 1 and communicate with the inner cavity of the electrolytic cell body 1; along the height direction of the electrolytic cell body 1, the height of the inlet 9 is the same as the height of the outlet 10; the inlet baffle is an L-shaped baffle, including a vertical plate and a horizontal plate, with a through hole provided on the horizontal plate, and the horizontal plate contacts the tank wall where the inlet 9 is disposed; the opening of the L-shaped baffle faces the inlet 9, and the inlet 9 is higher than the height of the horizontal plate; the outlet baffle 12 is disposed between the first anode and the tank wall where the outlet 10 is disposed.

[0036] In this invention, the first anode refers to the anode closest to the outlet. The inlet, outlet, inlet baffle, and outlet baffle are arranged as described above to facilitate a stable, bottom-up, piston-like laminar flow of the electrolyte within the electrolytic cell. The electrolyte entering from the inlet spreads horizontally under the action of the inlet baffle, and then flows smoothly downwards through the through-holes in the horizontal plate of the inlet baffle under gravity, before exiting from the outlet. When the electrolyte flows out of the cell, it is prone to turbulence due to ultrasonic vibration, leading to fluctuations in outlet flow and unstable pressure. The outlet baffle converts turbulence into stable laminar flow, preventing problems such as cavitation and overload in subsequent pumps and pipelines due to sudden flow changes.

[0037] In some embodiments of the present invention, the electrolysis device further includes a circulating filtration unit 200, wherein the circulating filtration unit 200 includes a circulating pump 13 and a filter 14, the inlet of the circulating pump 13 is connected to the outlet 10 through a first pipe, and the outlet of the circulating pump 13 is connected to the inlet 9 through a second pipe; a valve is provided on the first pipe, and a filter 14 is provided on the second pipe.

[0038] In this application, the circulating pump can drive the flow of electrolyte within the electrolytic cell, thereby delivering fresh electrolyte to the anode region and enhancing Cu... 2+ On the one hand, it improves mass transfer efficiency; on the other hand, it can remove electrolytic products and heat, delaying electrolyte aging, thereby improving electrolysis efficiency and copper deposition quality. The filter can filter the electrolyte, promptly removing impurities and helping to maintain electrolyte purity and electrolytic reaction stability.

[0039] In some embodiments of the present invention, the filter 14 is a precision filter. The filter element of the precision filter is selected from PTFE filter elements, and the PTFE filter element has a pore size of 50nm-100nm. The precision filter can better filter out suspended anode mud particles in the electrolyte, further reducing the turbidity of the electrolyte and maintaining its cleanliness.

[0040] In some embodiments of the present invention, the electrolysis apparatus further includes a control unit 300; wherein the control unit 300 includes an electrodeposition control module, an ultrasonic control module, and a flow control module, the electrodeposition control module and the ultrasonic control module being connected to the electrolysis unit 100, and the flow control module being connected to the circulating filtration unit 200.

[0041] In this application, the electrodeposition control module can adjust the current density during electrolysis by regulating the current. The ultrasonic control module is used to adjust the ultrasonic frequency, power density, and operating mode (continuous / pulse) of the first and second ultrasonic probes. The flow control module is used to adjust the circulation rate of the electrolyte in the circulating pump.

[0042] In some embodiments of the present invention, the control unit is a computer control system, and more preferably a multi-field coupled intelligent control system.

[0043] In this invention, the computer control system includes a sensor group, an actuator group, a programmable logic controller (PLC), a communication module, and a human-machine interface. The sensor group includes temperature sensors, pH sensors, and turbidity sensors, used to collect real-time operating parameters of the electrolysis unit, such as current, voltage, temperature, and turbidity. The PLC receives signals from the sensor group, runs a built-in multi-field collaborative optimization algorithm, and issues control commands to the actuator group. The actuator group receives signals from the PLC and executes its commands accordingly, for example, adjusting the operating status of the electrodeposition power supply, the ultrasonic transducer array, and various pumps and valves. The human-machine interface is a touchscreen used to set process parameters, start preset programs, and display real-time data and equipment status. The communication module connects all actuators (power supply, ultrasonic generator, circulating pump, valves, etc.) and sensors (temperature, pH, flow rate, etc.) via cables or a network, and is uniformly commanded and scheduled by the control unit.

[0044] A second aspect of the present invention provides a cathode in which an ultrasonic probe is embedded and sealed at one end; when the cathode is in use, the ultrasonic probe is positioned above the electrolyte.

[0045] The cathode described in the second aspect of the present invention is the same as the cathode in the electrolysis device described in the first aspect of the present invention, and will not be described in detail hereafter.

[0046] A third aspect of the present invention provides a method for preparing ultra-high purity copper, wherein the preparation method is carried out in the electrolysis apparatus described in the first aspect of the present invention.

[0047] In this invention, before using the electrolysis device, the anode is first placed in the diaphragm bag of the anode chamber, and the cathode is installed in the main body of the electrolysis cell. Then, the electrolyte can be injected, the first ultrasonic probe is placed above the electrolyte, and then electrolysis begins to produce ultra-high purity copper.

[0048] In some embodiments of the present invention, the method for preparing ultra-high purity copper includes the following steps: (1) Initial nucleation stage: The electrolyte is added to the main body of the electrolytic cell, and the first stage of electrodeposition is carried out under the first stage of ultrasonic assistance to form an initial copper layer on the cathode; The operating conditions for the first segment of ultrasound include: activating the first ultrasonic probe, applying ultrasound in continuous mode, with an ultrasonic frequency of 80kHz-100kHz and a power density of 150W / m². 2 -350W / m 2 ; (2) High-speed growth period: Adjust the first ultrasonic probe, start the second ultrasonic probe, and perform the second stage of electrodeposition under the assistance of the second stage of ultrasound to form an intermediate copper layer on the cathode; The operating conditions for the second segment of ultrasound include: the ultrasound waves applied by the first ultrasound probe are in pulse mode, the ultrasound frequency is 40kHz-60kHz, and the power density is 400W / m². 2 -600W / m 2 The second ultrasonic probe is used in continuous mode, with an ultrasonic frequency of 5kHz-25kHz and a power density of 200W / m². 2 -400W / m 2 ; (3) Surface finishing stage: readjust the first ultrasonic probe, turn off the second ultrasonic probe, and perform the third stage of electrodeposition under the assistance of the third stage of ultrasound to form ultra-high purity copper on the cathode. The operating conditions for the third ultrasonic segment include: the ultrasonic waves applied by the first ultrasonic probe are in continuous mode, the ultrasonic frequency is 60kHz-80kHz, and the power density is 100W / m². 2 -250W / m 2 .

[0049] In this invention, during the first stage of electrodeposition, the ultrasound provided by the first ultrasonic probe has a mild cavitation intensity, effectively promoting the formation of numerous crystal nuclei and refining the initial grains without disturbing the overall electrolyte, thereby obtaining a dense initial copper layer. During the second stage of electrodeposition, the first and second ultrasonic probes work together to, on the one hand, flush away the anode mud generated by anode dissolution from the anode surface and force it to settle downwards and be collected in the diaphragm bag; on the other hand, they can disrupt the cathode diffusion layer, greatly enhancing mass transfer and forming an acoustic barrier in the anode region to inhibit anode mud diffusion. Thus, high-speed deposition can be completed on the cathode. During the third stage of electrodeposition, the ultrasonic action of the first ultrasonic probe can smooth the cathode surface to obtain a smooth and dense electrolytic product. Therefore, this invention can prepare ultra-high purity copper with high purity, good uniformity, and excellent density.

[0050] In some embodiments of the present invention, the electrolyte comprises copper sulfate and sulfuric acid, wherein the concentration of copper ions in the electrolyte is 40 g / L-50 g / L and the concentration of H2SO4 is 150 g / L-180 g / L.

[0051] The preparation method provided in this invention can produce high-purity and well-dense ultra-high-purity copper without adding various additives to the electrolyte.

[0052] In some embodiments of the present invention, the electrolyte temperatures for the first electrodeposition stage, the second electrodeposition stage, and the third electrodeposition stage are each individually selected from 15°C to 50°C, preferably 35°C to 45°C; and the current densities are each individually selected from 80 A / m. 2 -250A / m 2 Preferably 200A / m 2 -230A / m 2 .

[0053] In this invention, the electrodeposition operating conditions (electrolyte temperature and current density) for the first, second, and third electrodeposition stages can be the same or different. When the electrodeposition operating conditions for the first, second, and third stages are the same, it helps to further improve the uniformity of the electrolytic product (e.g., ultra-high purity copper).

[0054] In some embodiments of the present invention, the sum of the deposition times of the first electrodeposition, the second electrodeposition, and the third electrodeposition is the total deposition time, the deposition time of the second electrodeposition accounts for 90%-95% of the total deposition time, and the deposition times of the first electrodeposition and the third electrodeposition each account for 5%-10% of the total deposition time.

[0055] In this invention, taking a total deposition time of 50 hours as an example, the deposition time of the first stage of electrodeposition is ≤2 hours, for example, 2 hours; the deposition time of the third stage of electrodeposition is ≤2 hours, for example, 2 hours; and the remaining time is the deposition time of the second stage of electrodeposition, 46-50 hours, for example, 46 hours.

[0056] In some embodiments of the present invention, during the second electrodeposition, the pulse mode of the first ultrasonic probe operates for 1-3 seconds, for example, 1 second, 1.5 seconds, 2 seconds, 2.5 seconds, 3 seconds, and any number between these values; the interval time is 0.5-1.5 seconds, for example, 0.5 seconds, 0.8 seconds, 1 second, 1.2 seconds, 1.4 seconds, 1.5 seconds, and any number between these values.

[0057] In this invention, during the high-speed growth phase, the pulsed ultrasonic emission has an intermittent period compared to the continuous mode. This intermittent period allows ions more opportunities for orderly adsorption and alignment, suppressing the preferential growth of dendrites and columnar crystals and promoting the formation of equiaxed fine crystals. This reduces crystal defects and improves the density and purity of the electrolytic product.

[0058] In some embodiments of the present invention, the circulation flow rate of the electrolyte in the first electrodeposition stage, the second electrodeposition stage, and the third electrodeposition stage is individually selected from 400L / h to 600L / h.

[0059] In some embodiments of the present invention, the method further includes real-time monitoring of the turbidity of the electrolyte, and when the turbidity of the electrolyte exceeds a preset threshold, the electrolyte circulation flow rate is increased accordingly.

[0060] In this invention, the preset threshold for electrolyte turbidity is 1.5 NTU-2.5 NTU. When the electrolyte turbidity exceeds the preset threshold, the circulation flow rate increases by 20 L / h-60 L / h for every 0.5 NTU increase in electrolyte turbidity. Once the electrolyte turbidity decreases to the preset threshold, the circulation flow rate is restored to its initial state before adjustment.

[0061] In some embodiments of the present invention, the method further includes removing the cathode after the third stage of electrodeposition is completed, and immediately cleaning and drying it using a cycle of high-purity deionized water, dilute sulfuric acid solution, and high-purity deionized water to obtain ultra-high-purity copper.

[0062] In this invention, there are no special limitations on the cleaning and drying after the cathode is removed, and conventional cleaning and drying operations in the art can be used in this invention.

[0063] The present invention will now be described in detail with reference to specific embodiments thereof, but it should be understood that the scope of protection of the present invention is not limited to the embodiments.

[0064] Example 1 in Figure 1The electrolysis is carried out in the apparatus shown. The anode is a 4N refined copper plate, and the cathode is a titanium plate with a 5µm thick titanium dioxide film formed by surface micro-arc oxidation. Ten first ultrasonic probes containing miniature piezoelectric ceramic transducers are evenly arranged on both sides of the cathode plate, and ten second ultrasonic probes containing miniature piezoelectric ceramic transducers are symmetrically arranged in the anode chamber. The diaphragm bag is double-layered and made of Teflon fiber; the filter is a precision filter with a PTFE filter element and a pore size of 50nm-100nm; the control system adopts a PLC-based multi-field coupling intelligent control system with a built-in staged control algorithm. The electrolyte includes copper sulfate and sulfuric acid, with a copper ion concentration of 45g / L and an H2SO4 concentration of 170g / L.

[0065] Example 1 (1) Add the electrolyte to the main body of the electrolytic cell, start the first ultrasonic probe and the circulation pump, and perform the first stage of electrodeposition under the first stage of ultrasonic assistance to form an initial copper layer on the cathode; wherein, the electrodeposition temperature is 40±0.5℃ and the current density is 220A / m 2 The electrodeposition time was 2 hours; the ultrasonic waves applied by the first ultrasonic probe were in continuous mode, with an ultrasonic frequency of 90 kHz and a power density of 150 W / m². 2 The circulation flow rate of the circulating pump is 400 L / h; (2) Adjust the first ultrasonic probe and simultaneously start the second ultrasonic probe to perform the second stage of electrodeposition under the assistance of the second stage of ultrasound, forming an intermediate copper layer on the cathode; wherein the electrodeposition temperature is 40±0.5℃ and the current density is 220A / m 2 The electrodeposition time was 48 hours; the ultrasonic waves applied by the first ultrasonic probe were in pulse mode (on for 2 seconds, off for 1 second), with an ultrasonic frequency of 50 kHz and a power density of 400 W / m². 2 The second ultrasonic probe has an ultrasonic frequency of 25kHz and a power density of 200W / m². 2 ; (3) Adjust the first ultrasonic probe again, turn off the second ultrasonic probe, and perform the third stage of electrodeposition under the assistance of the third stage of ultrasound to form ultra-high purity copper on the cathode; wherein, the electrodeposition temperature is 40±0.5℃ and the current density is 220A / m 2 The electrodeposition time was 2 hours; the ultrasonic waves applied by the first ultrasonic probe were in continuous mode, with an ultrasonic frequency of 60 kHz and a power density of 100 W / m². 2 ; (4) After electrodeposition, the cathode 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. Throughout the electrodeposition process, turbidity is monitored in real time. The preset threshold for electrolyte turbidity is 1.5 NIU. When the electrolyte turbidity exceeds the preset threshold, the electrolyte circulation flow rate is increased by 30 L / h for every 0.5 NIU increase in electrolyte turbidity. Once the electrolyte turbidity drops to 1.5 NIU, the circulation flow rate is restored to the pre-adjustment level of 400 L / h.

[0066] Test Example 1 The ultra-high purity copper prepared in Example 1 was analyzed by glow discharge mass spectrometry (GDMS), and the results are shown in Table 1: Table 1

[0067] As shown in Table 1, the ultra-high purity copper prepared in Example 1 has a purity of 99.99999%, which meets the 7N standard.

[0068] Test Example 2 The ultra-high purity copper prepared in Example 1 was characterized by metallographic microscopy, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that ultra-high purity copper has fine and uniform grains, a dense structure, and no visible defects.

Claims

1. An electrolysis apparatus, characterized in that, The electrolysis device includes an electrolysis unit (100), which includes an electrolysis cell body (1), an anode (2), a cathode (3), and an anode chamber (4); wherein, along the length of the electrolysis cell body (1), the anode (2) and the cathode (3) are alternately arranged in the inner cavity of the electrolysis cell body (1); the anode (2) is disposed in the anode chamber (4); The electrolysis unit (100) also includes a first ultrasonic probe (5), which is embedded and sealed on the upper part of the cathode (3) along the height direction of the electrolysis cell body (1).

2. The electrolysis apparatus according to claim 1, characterized in that, The embedded sealing installation adopts an embedded sealing installation structure; The embedded sealing installation structure includes an installation groove, sealant, and cover plate. The installation groove is located on the upper part of the cathode (3), the first ultrasonic probe (5) is installed in the installation groove, the installation groove is filled with sealant, and the cover plate is located on the installation groove and is sealed to the cathode (3) by welding.

3. The electrolysis apparatus according to claim 1 or 2, characterized in that, The first ultrasonic probe (5) is a multi-frequency ultrasonic probe, and the ultrasonic frequency of the multi-frequency ultrasonic probe is 40kHz-100kHz.

4. The electrolysis apparatus according to claim 1, characterized in that, The cathode (3) is selected from a titanium plate, and an oxide film is disposed on the titanium plate; The oxide film is made of one or more of titanium dioxide, tungsten oxide, and titanium-tungsten composite oxide, and the thickness of the oxide film is 3µm-10µm.

5. The electrolysis apparatus according to claim 1, characterized in that, The electrolysis unit (100) further includes a diaphragm bag (6), wherein the anode (2) is disposed in the diaphragm bag (6), and the diaphragm bag (6) is disposed in the anode chamber (4); The diaphragm bag (6) is a double-layer diaphragm bag, and the material is selected from one or more of polytetrafluoroethylene fiber, polypropylene fiber, polyethylene fiber, and polyvinylidene fluoride fiber, and the mesh size of its filter layer is ≤50µm.

6. The electrolysis apparatus according to claim 1, characterized in that, The electrolysis unit (100) also includes a second ultrasonic probe (7), which is disposed on the inner wall of the anode chamber (4).

7. The electrolysis apparatus according to claim 6, characterized in that, The electrolysis unit further includes an ultrasonic generator (8); wherein the ultrasonic generator (8) is connected to the first ultrasonic probe (5) and the second ultrasonic probe (7) respectively.

8. The electrolysis apparatus according to claim 1, characterized in that, The electrolysis unit further includes an inlet (9), an outlet (10), an inlet baffle (11), and an outlet baffle (12); along the length of the electrolytic cell body (1), the inlet (9) and the outlet (10) are respectively located on two opposite sides of the electrolytic cell body (1); along the height of the electrolytic cell body (1), the height of the inlet (9) is the same as the height of the outlet (10); The inlet baffle (11) is an L-shaped baffle, including a vertical plate and a horizontal plate. A through hole is provided on the horizontal plate, and the horizontal plate is in contact with the tank wall where the liquid inlet (9) is provided. The opening of the L-shaped baffle faces the liquid inlet (9), and the liquid inlet (9) is higher than the height of the horizontal plate. The outlet baffle (12) is provided between the first anode and the tank wall where the liquid outlet (10) is provided.

9. A cathode, characterized in that, An ultrasonic probe is embedded and sealed at one end of the cathode; when the cathode is in use, the ultrasonic probe is positioned above the electrolyte.

10. A method for preparing ultra-high purity copper, characterized in that, The preparation method is carried out in the electrolysis apparatus described in any one of claims 1-8.

11. The preparation method according to claim 10, characterized in that, The preparation method includes the following steps: (1) Initial nucleation stage: The electrolyte is added to the main body of the electrolytic cell, and the first stage of electrodeposition is carried out under the first stage of ultrasonic assistance to form an initial copper layer on the cathode; The operating conditions for the first segment of ultrasound include: activating the first ultrasonic probe, applying ultrasound in continuous mode, with an ultrasonic frequency of 80kHz-100kHz and a power density of 150W / m². 2 -350W / m 2 ; (2) High-speed growth period: Adjust the first ultrasonic probe, start the second ultrasonic probe, and perform the second stage of electrodeposition under the assistance of the second stage of ultrasound to form an intermediate copper layer on the cathode; The operating conditions for the second segment of ultrasound include: the ultrasound waves applied by the first ultrasound probe are in pulse mode, the ultrasound frequency is 40kHz-60kHz, and the power density is 400W / m². 2 -600W / m 2 The second ultrasonic probe is used in continuous mode, with an ultrasonic frequency of 5kHz-25kHz and a power density of 200W / m². 2 -400W / m 2 ; (3) Surface finishing stage: readjust the first ultrasonic probe, turn off the second ultrasonic probe, and perform the third stage of electrodeposition under the assistance of the third stage of ultrasound to form ultra-high purity copper on the cathode. The operating conditions for the third ultrasonic segment include: the ultrasonic waves applied by the first ultrasonic probe are in continuous mode, the ultrasonic frequency is 60kHz-80kHz, and the power density is 100W / m². 2 -250W / m 2 .

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