Electrodeposition device and method for regulating and controlling apparent density and morphology of copper powder through external field strengthening

Abstract

The invention discloses an electrodeposition device and method for regulating and controlling the apparent density and morphology of copper powder through an external field enhanced electrodeposition method, and belongs to the technical field of metal powder preparation. Activating the anode plate to form a uniform and compact lead dioxide coating on the surface of the anode plate; an electro-deposition device capable of automatically feeding an additive is adopted, and the device is provided with a stirring container and a temperature control base, so that constant-temperature heating can be realized; the circulation of the electrodeposition liquid of the stirring container and the electrodeposition tank can be realized through the liquid conveying control mechanism, the liquid inlet pipe and the liquid return pipe to maintain the stability of solution components; and a plurality of activated anode plates and cathode plates are alternately arranged in an electrodeposition cell at intervals, auxiliary ultrasonic enhanced electrodeposition treatment is carried out on the electrodeposition cell, electrodeposition copper powder is obtained, and the apparent density is recorded. According to the electrodeposition device, integrated collaborative operation of anode pretreatment activation, ultrasonic external field strengthening and copper electrodeposition is met, the automation degree is high, accurate regulation and control and morphology optimization of the apparent density of the copper powder can be achieved, and the production stability and the product consistency of the copper powder are improved.

Description

Technical Field

[0001] This invention belongs to the field of metal powder preparation technology, and particularly relates to an electrodeposition apparatus and method for external field enhancement to control the loose packing density and morphology of copper powder. Background Technology

[0002] With the rapid development of technologies such as powder metallurgy, conductive pastes, and additive manufacturing (3D printing), the demand for high-performance metal powders has increased dramatically. In particular, powders with lower bulk density and better flowability are required to meet the needs of complex structure filling, efficient printing, and dense molding. Among the many methods for preparing metal powders, electrodeposition has attracted much attention due to its advantages such as low cost, strong process controllability, ease of large-scale production, and the ability to directly obtain high-purity powders. It has particularly important applications in the production of copper powder with specific morphologies (such as dendritic and spherical shapes). Copper powder, with its excellent electrical and thermal conductivity, has become a key basic material in these fields.

[0003] However, traditional electrodeposition processes often suffer from high bulk density and poor flowability when preparing copper powder, which seriously affects the efficiency of subsequent pressing, sintering, or coating processes and the performance of the final product, and may even cause product defects, limiting its potential in high-end applications. Therefore, there is an urgent need for an electrodeposition apparatus and method that can effectively control the bulk density and morphology of copper powder. Summary of the Invention

[0004] Technical problem solved: To address the technical defects of copper powder prepared by traditional electrodeposition processes in the prior art, such as high loose packing density, poor flowability, and irregular morphology, this invention provides an electrodeposition device and method for external field enhancement to control the loose packing density and morphology of copper powder. This electrodeposition device can meet the integrated collaborative operation of anode pretreatment activation, ultrasonic external field enhancement, and copper electrodeposition, with a high degree of automation. It can achieve precise control of the loose packing density and morphology optimization of copper powder, thereby improving the stability of copper powder production and product consistency.

[0005] Technical solution: The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using an external field enhanced electrodeposition method, as described in this invention, comprises: An automatic filling thermostatic mixing tank is provided, wherein a mixing container is provided inside the automatic filling thermostatic mixing tank, and a stirrer is provided inside the mixing container; at least one automatic filling mechanism is provided on the top of the automatic filling thermostatic mixing tank, and each automatic filling mechanism is connected to the mixing container through a material conveying pipe; an inlet pipe and a return pipe are respectively provided on both sides of the automatic filling thermostatic mixing tank, which connect the mixing container to the electrowinning tank, and both the inlet pipe and the return pipe are equipped with a liquid conveying control mechanism to control the liquid flow rate; The electrodeposition cell has holes at both ends for connecting the inlet pipe and the return pipe, and multiple limiting grooves are evenly spaced on the inner side wall of the electrodeposition cell. An anode plate and a cathode plate are spaced apart in the limiting grooves. A combined non-contact ultrasonic transducer is attached to the bottom of the electrodeposition cell.

[0006] Preferably, the automatic filling mechanism includes a mounting base and a dust cover cylinder disposed on the mounting base, wherein a pressure-sensitive spring assembly is provided inside the dust cover cylinder, and a material flow channel is formed between the pressure-sensitive spring assembly and the inner wall of the dust cover cylinder; The pressure-sensitive spring assembly includes a tapered pressure-sensitive end, a malleable spring wall, an M-shaped spring assembly, a hollow disc, and a triangular support base; the malleable spring wall is arranged circumferentially between the tapered pressure-sensitive end and the hollow disc, and an M-shaped spring assembly connecting the tapered pressure-sensitive end and the hollow disc is arranged on the inner side of the malleable spring wall. A triangular support base is provided on the lower circumference of the hollow disc. The legs of the triangular support base are connected to the inner wall of the dust cover. A sealing ring is provided at the lower part of the triangular support base to connect the dust cover and the mounting base. One end of the material conveying pipe is inserted into the sealing ring.

[0007] Preferably, the automatic filling constant temperature mixing tank is provided with an integral or separate mixing chamber and an installation chamber arranged vertically and correspondingly. The mixing container and liquid conveying control mechanism are respectively arranged in the mixing chamber. The side wall of the mixing container is provided with holes for the insertion of the liquid inlet pipe and the liquid return pipe. The automatic filling mechanism is respectively arranged at the top of the installation chamber, and the material conveying pipe is arranged in the installation chamber.

[0008] Preferably, the automatic filling constant temperature mixing box is provided with a control panel on the front side of the installation chamber. The control panel is provided with control buttons for controlling the opening and closing of the stirrer and the temperature control base, as well as a temperature display screen and a stirring speed display screen. The automatic filling constant temperature mixing box is provided with a transparent panel on the front side of the mixing chamber, and the mixing container is provided on the back side of the transparent panel.

[0009] Preferably, the liquid delivery control mechanism includes two sets of control pipes, one for the inlet pipe and the other for the return pipe, respectively, which are respectively arranged on both sides of the stirring container; The liquid delivery control mechanism includes a longitudinally arranged conical base plate. An active roller is located at the center of the cone apex of the conical base plate. The active roller is located at the center of the curved arm of the triangular structure, and locking rollers are located at both ends of the curved arm. A locking stationary roller is located at the outer edge of the upper end of the conical base plate, corresponding to the locking roller. The inlet pipe and return pipe pass through the channel formed between the locking stationary roller, the active roller, and the locking roller. By driving the curved arm to rotate, the locking roller rotates along the conical base plate and cooperates with the locking stationary roller to achieve liquid flow regulation.

[0010] Preferably, a temperature control base is provided at the lower end of the mixing container, and an opening baffle is provided at the top of the mixing container for inserting a material conveying pipe; the agitator includes a stirring rod disposed inside the mixing container and a stirring paddle disposed at its lower end.

[0011] Preferably, the anode plate is a Pb-Sn-Ca alloy plate, and the cathode plate is a 316L stainless steel plate.

[0012] This invention also discloses an electrodeposition method for controlling the loose packing density and morphology of copper powder using an external field-enhanced electrodeposition apparatus, comprising the following steps: Step 1: Place the anode plates sequentially into the corresponding limiting slots of the electrodeposition cell; add the material to the stirring container using an automatic filling mechanism to prepare a pretreatment solution with Cu as its component. 2+ The concentration of H2SO4 was 8 g / L and the concentration of H2SO4 was 120 g / L. The pretreatment solution prepared in the stirring container was injected into the electrodeposition cell through the inlet pipe and the liquid delivery control mechanism. The electrodeposition device was started at a temperature of 25℃ and a current density of 1200 A / m. 2 The anode plate was activated for 24 hours under certain conditions, resulting in a uniform and dense lead dioxide coating on its surface. Step 2: Drain the pretreatment solution stored in the electrodeposition cell; arrange the cathode and anode plates alternately in the electrodeposition cell; control the automatic filling mechanism to supply liquid to the stirring container through the material conveying pipe to prepare Cu. 2+ A copper sulfate electrodeposition solution with a concentration of 8 g / L, H2SO4 concentration of 120 g / L, SDBS concentration of 0.5 g / L, and PVP concentration of 1.5 g / L was prepared. During the electrodeposition process, the dynamic balance of the concentration of the copper sulfate electrodeposition solution in the electrodeposition tank was maintained by adjusting the opening of the liquid delivery control mechanism connected to the inlet and outlet pipes. Step 3: Turn on the power supply of the electrodeposition cell and the ultrasonic generator connected to the non-contact ultrasonic transducer, with the ultrasonic frequency at 40kHz, ultrasonic power at 10-20W, electrodeposition cell temperature at 50-52℃, and current density at 1200A / m. 2 Under the specified conditions, the ultrasonic electrowinning process was carried out for 30 minutes, and the electrowinning copper powder was collected and the loose packing density was recorded.

[0013] Preferably, the electrowinning cell in step 3 is made of polypropylene material with a temperature tolerance range of -20 to 120°C; the electrowinning cell is powered by an intelligent constant voltage power supply with a power supply voltage of 0-15V and a power supply current of 0-10A.

[0014] Preferably, in step 3, a Hall effect flowmeter is used to measure the loose bulk density of the copper powder. The funnel and density cup of the Hall effect flowmeter are made of brass, and the funnel angle is 60°. The formula for calculating the loose bulk density is: ρ=(Mm) / V; Where: ρ is the loose density of copper powder / (g / cm³) 3 M is the total mass of copper powder and container (g); m is the mass of container (g); V is the volume of container (cm³). 3 .

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The electrodeposition apparatus of the present invention can meet the integrated collaborative operation of anode pretreatment activation, ultrasonic external field enhancement and copper electrodeposition. It has a high degree of automation, realizes the efficient preparation of pretreatment solution and copper sulfate electrodeposition solution, and maintains the circulation of electrodeposition solution during copper electrodeposition, thereby achieving precise control of copper powder bulk density and morphology optimization, and improving the stability of copper powder production and product consistency. 2. This invention achieves precise control of the loose packing density of copper powder. A dense PbO2 coating is formed through anode plate pretreatment activation. Combined with the cavitation effect of a 40kHz ultrasonic field (10~20W), ion mass transfer is accelerated, cathode concentration polarization is suppressed, and the diffusion layer is destroyed, grains are refined, and dendrite growth is promoted, resulting in a porous dendritic structure of copper powder and significantly reducing the loose packing density. Under optimized process conditions (14W ultrasonic assistance), the loose packing density of copper powder can be reduced to 0.569 g / cm³. 3 Compared to the control group without ultrasound (0.871 g / cm³), 3 The content decreased by 34.7%, and the batch fluctuation was ≤0.1g / cm. 3 Production stability has been greatly improved; 3. This invention achieves optimization of copper powder morphology and performance improvement. The synergistic effect of ultrasonic field and additives (SDBS+PVP) makes the copper powder morphology more uniform, with a robust main trunk, significant suppression of secondary dendrites, concentrated particle distribution, and a median particle size refined to 6.29μm. The fluidity is significantly improved, meeting the requirements of high-end powder metallurgy for low density and high fluidity. At the same time, the copper powder has high purity, excellent electrical and thermal conductivity, and a wider range of applications. 4. The method of this invention is stable and reliable. The anodic activation treatment improves the anodic reaction activity and reduces the current fluctuation caused by passivation. The electrowinning cell uses polypropylene material and intelligent constant voltage power supply. The power supply voltage is adjustable from 0-15V and the current is adjustable from 0-10A. The temperature control accuracy is ±0.5℃ and the electrode spacing is fixed at 5cm, ensuring that the process parameters are stable and controllable and easy to scale up industrially. 5. The electrodeposition device of this invention is reasonably designed. The dedicated electrodeposition device integrates multiple functions such as automatic filling, constant temperature stirring, ultrasonic enhancement, and solution circulation. The automatic filling mechanism realizes the quantitative addition of chemical materials and additives; the non-contact ultrasonic transducer provides a uniform ultrasonic field for the electrodeposition tank; the liquid delivery control mechanism and the liquid inlet pipe and return pipe ensure the stability of the composition of the electrodeposition solution in the electrodeposition tank; the overall structure of the device is convenient to operate, has a wide range of applications, and can effectively ensure the consistency of product quality. Attached Figure Description

[0016] Figure 1 This is a flowchart of the electrowinning method of the present invention; Figure 2 These are bar charts showing the loose packing density of Embodiments 1-2 and Comparative Examples 1-2 of the present invention; Figure 3 These are SEM images of copper powder from Examples 1-2 and Comparative Examples 1-2 of the present invention; Figure 4 The LSV curves are for the copper powder deposition process in Examples 1-2 and Comparative Examples 1-2 of this invention. Figure 5 These are particle size analysis diagrams of copper powder from Examples 1-2 and Comparative Examples 1-2 of the present invention; Figure 6 This is a three-dimensional structural schematic diagram of the electrodeposition apparatus of the present invention; Figure 7 for Figure 6 Front view cross-sectional view of the electrodeposition apparatus; Figure 8 for Figure 6 Side view of the structure of an automatic filling thermostatic mixing tank; Figure 9 for Figure 6 A side view of the structure of the electrowinning cell; Figure 10 for Figure 7 Front view of the liquid delivery control mechanism; Figure 11 for Figure 6 Schematic diagram of the automatic filling mechanism ((a) perspective view; (b) sectional view); Figure 12 for Figure 11 Material flow diagram of automatic filling mechanism ((a) first state; (b) second state).

[0017] Reference numerals: 1. Automatic filling thermostatic mixing tank; 101. Mixing chamber; 102. Installation chamber; 2. Automatic filling mechanism; 201. Mounting base; 202. Dust cover; 203. Conical pressure-sensitive end; 204. Plastic spring wall; 205. M-shaped spring assembly; 206. Hollowed-out disc; 207. Triangular support base; 208. Sealing ring; 209. Material flow channel; 3. Control panel; 4. Transparent panel; 5. 6. Liquid inlet pipe; 7. Liquid return pipe; 8. Electrowinning tank; 9. Non-contact ultrasonic transducer; 10. Anode plate; 11. Cathode plate; 12. Temperature digital display screen; 13. Stirring speed digital display screen; 14. Stirring container; 15. Stirrer; 16. Liquid conveying control mechanism; 17. Conical base plate; 18. Drive roller; 19. Curved arm; 10. Locking moving roller; 10. Locking stationary roller; 11. Material conveying pipe; 12. Temperature control base. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings. Figures 1-12 The technical solutions of the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0019] like Figures 6-12 As shown, the present invention discloses an electrodeposition apparatus for controlling the loose packing density and morphology of copper powder by external field enhanced electrodeposition method, comprising an automatic filling constant temperature stirring tank 1, an electrodeposition tank 7, and supporting components, the specific structure of which is shown below.

[0020] like Figures 6-8 As shown, the automatic filling thermostatic mixing chamber 1 serves as a storage, stirring, preparation, and temperature control unit for copper electrowinning solution and pretreatment solution. The automatic filling thermostatic mixing chamber 1 contains a stirring container 13, within which a stirrer 14 is installed. A temperature control base 17 is correspondingly installed at the lower end of the stirring container 13, providing a temperature control accuracy of ±0.5℃. An open baffle is provided at the top of the stirring container 13 for inserting a material conveying pipe 16. The stirrer 14 includes a stirring rod installed inside the stirring container and a stirring paddle at its lower end. A control panel 3 is located on the front side of the installation chamber 102 of the automatic filling thermostatic mixing chamber 1. The control panel 3 includes control buttons for opening and closing the stirrer 14 and the temperature control base 17, as well as a temperature digital display screen 11 and a stirring speed digital display screen 12. A transparent panel 4 is located on the front side of the stirring chamber 101 of the automatic filling thermostatic mixing chamber 1, with the stirring container 13 correspondingly located on the back side of the transparent panel 4. The working status of each component within the stirring chamber can be observed through the transparent panel.

[0021] like Figure 6As shown, the top of the automatic filling thermostatic mixing tank 1 is provided with at least one automatic filling mechanism 2. Each automatic filling mechanism 2 is connected to the mixing container 13 through a material conveying pipe 16. The automatic filling thermostatic mixing tank 1 is provided with an inlet pipe 5 and a return pipe 6 on both sides, which are connected to the mixing container 13 and the electrowinning tank 7. Both the inlet pipe 5 and the return pipe 6 are equipped with a liquid conveying control mechanism 15 to control the liquid flow rate. The circulation of the electrowinning liquid in the electrowinning tank 7 is realized through the liquid conveying control mechanism 15 and the inlet pipe 5 and the return pipe 6, and its composition is kept stable.

[0022] The automatic filling constant temperature mixing tank 1 has an integral or separate mixing chamber 101 and an installation chamber 102 arranged vertically and correspondingly. The mixing container 13 and the liquid conveying control mechanism 15 are respectively arranged in the mixing chamber 101. The side wall of the mixing container 13 is provided with holes for the liquid inlet pipe 5 and the liquid return pipe 6 to be inserted. The automatic filling mechanism 2 is respectively arranged at the top of the installation chamber 102, and the material conveying pipe 16 is arranged in the installation chamber 102.

[0023] The automatic filling mechanism 2 includes a mounting base 201 and a dust cover 202 disposed on the mounting base 201. A pressure-sensitive spring assembly is provided inside the dust cover 202. A material flow channel 209 is formed between the pressure-sensitive spring assembly and the inner wall of the dust cover 202. When the material to be added is added into the dust cover 202, the pressure-sensitive spring assembly is compressed and changes the material flow channel, so that the material can be added to the mixing container stably and evenly. The pressure-sensitive spring assembly includes a tapered pressure-sensitive end 203, a malleable spring wall 204, an M-shaped spring assembly 205, a hollowed-out disc 206, and a triangular support base 207. A malleable spring wall 204 is circumferentially arranged between the tapered pressure-sensitive end 203 and the hollowed-out disc 206, and an M-shaped spring assembly 205 connecting the tapered pressure-sensitive end 203 and the hollowed-out disc 206 is arranged inside the malleable spring wall 204. When compressed, the tapered pressure-sensitive end 203 deforms through the malleable spring wall 204 and the M-shaped spring assembly 205, thereby changing the width of the material flow channel 209 (e.g., ...). Figure 12 (As shown), thereby controlling the supply flow of the agent. A triangular support base 207 is provided circumferentially on the lower side of the hollow disc 206. The legs of the triangular support base 207 are connected to the inner wall of the dust cover 202, and a sealing ring 208 is provided at the lower part of the triangular support base 207 to connect the dust cover 202 and the mounting base 201. One end of the material conveying pipe 16 is inserted into the sealing ring 208. The additive enters the material conveying pipe 16 through the material flow channel and through the gap of the triangular support base 207. This automatic filling mechanism 2 can realize the quantitative addition of additives while isolating external impurities from contamination.

[0024] like Figure 7 and Figure 10As shown, the liquid delivery control mechanism 15 includes two sets of control pipes 5 and 6 respectively, which are arranged on both sides of the stirring container 13. The liquid delivery control mechanism 15 includes a longitudinally arranged conical base plate 151. An active roller 152 is arranged at the center of the cone apex of the conical base plate 151. The active roller 152 is arranged at the center of the triangular curved arm 153. Locking rollers 154 are arranged at both ends of the curved arm 153. A locking stationary roller 155 is arranged at the outer edge of the upper end of the conical base plate 151 and corresponding to the locking roller 154. The inlet pipe 5 and the return pipe 6 pass through the channel formed between the locking stationary roller 155, the active roller 152 and the locking roller 154. By driving the curved arm 153 to rotate, the locking roller 154 rotates along the conical base plate 151 and cooperates with the locking stationary roller 155 to achieve liquid flow regulation. The widths of the active roller 152, the locking roller 154, and the locking stationary roller 155 are basically the same and slightly larger than the diameters of the inlet pipe 5 and the return pipe 6. When it is necessary to disconnect the inlet pipe 5 or the return pipe 6, the active roller 152 is controlled to drive the crank arm to rotate (the drive mechanism, such as the drive motor, is not shown in the figure), so that one of its locking rollers 154 moves closer to the locking stationary roller 155 to gradually clamp the inlet pipe 5 or the return pipe 6 until it is shut off, thus completing the adjustment of the liquid flow until it is cut off. When it is necessary to connect the inlet pipe 5 or the return pipe 6, the active roller 152 is controlled to drive the crank arm to rotate, so that the locking roller 154 moves away from the locking stationary roller 155, thus gradually relaxing the inlet pipe 5 or the return pipe 6 until the liquid flow is adjusted until it is fully opened. The liquid delivery control mechanism 15, in conjunction with the inlet pipe and return pipe, maintains the circulation of the electrowinning solution during the copper electrowinning process, thereby stabilizing the composition of the electrowinning solution in the electrowinning cell, enabling precise control of the loose packing density of copper powder and optimization of its morphology, and improving the stability of copper powder production and product consistency.

[0025] like Figures 6-7 and Figure 9 As shown, the electrodeposition tank 7 has holes at both ends for connecting the inlet pipe 5 and the return pipe 6, respectively. Multiple limiting grooves are evenly spaced on the inner wall of the electrodeposition tank 7. An anode plate 9 and a cathode plate 10 are spaced apart within these limiting grooves. The anode plate 9 is a Pb-Sn-Ca alloy plate, and the cathode plate 10 is a 316L stainless steel plate. The electrode spacing between the anode and cathode plates is fixed at 5 cm. The electrodeposition tank 7 is made of polypropylene material and has a temperature tolerance range of -20 to 120℃. It is powered by an intelligent constant voltage power supply with a voltage of 0-15V and a current of 0-10A. A combined non-contact ultrasonic transducer 8 is attached to the bottom of the electrodeposition tank 7. The power control range of the ultrasonic generator is 0-100W. The ultrasonic transducer uses a non-contact design to avoid direct contact with the electrodeposition solution, thus preventing contamination, and simultaneously forming a uniformly distributed ultrasonic field.

[0026] like Figure 1As shown, this invention also discloses an electrodeposition method for externally enhanced control of the loose packing density and morphology of copper powder, comprising the following steps: (1) Place the anode plates 9 sequentially into the corresponding limiting slots of the electrodeposition tank 7; add the material into the stirring container through the automatic filling mechanism 2, and prepare a pretreatment solution in the stirring container 13, the composition of which is Cu. 2+ The concentration of H2SO4 is 8 g / L and the concentration of H2SO4 is 120 g / L. The pretreatment solution prepared in the stirring container 13 is injected into the electrodeposition tank 7 through the liquid inlet pipe 5 and the liquid delivery control mechanism 15. The electrodeposition device is started at a temperature of 25°C and a current density of 1200 A / m. 2 Activation treatment under certain conditions for 24 hours resulted in a uniform and dense lead dioxide coating forming on the surface of the Pb-Sn-Ca anode plate. Among these, Cu... 2+ The solution is provided by CuSO4•5H2O and is prepared with deionized water to ensure that the impurity content meets the requirements for electrodeposition.

[0027] (2) Discharge the pretreatment solution stored in the electrodeposition tank 7; arrange the cathode plate and anode plate alternately in the electrodeposition tank, with the electrode spacing controlled at 5cm; control the automatic filling mechanism 2 to supply Cu to the stirring container 13 through the material conveying pipe 16. 2+ A copper sulfate electrodeposition solution with a concentration of 8 g / L, H2SO4 concentration of 120 g / L, sodium dodecylbenzenesulfonate (SDBS) concentration of 0.5 g / L, and polyvinylpyrrolidone (PVP) concentration of 1.5 g / L is used. During the electrodeposition process, the dynamic balance of the concentration of the copper sulfate electrodeposition solution in the electrodeposition tank 7 is maintained by adjusting the opening of the liquid delivery control mechanism 15 connected to the inlet pipe 5 and the return pipe 6.

[0028] (3) Start the power supply of the electrodeposition cell 7 and the ultrasonic generator connected to the non-contact ultrasonic transducer 8, and set the ultrasonic frequency to 40kHz, ultrasonic power to 10-20W (preferably 14W), electrodeposition cell temperature to 50-52℃, and current density to 1200A / m. 2 Under the specified conditions, the ultrasonic electrowinning process lasted for 30 minutes; after electrowinning, the electrowinning copper powder was collected and the loose packing density was recorded.

[0029] The loose packing density of copper powder was measured using a Hall effect flow meter. The funnel and density cup of the Hall effect flow meter were made of brass, and the funnel angle was 60°. The formula for calculating the loose packing density is: ρ = (Mm) / V; where: ρ is the loose packing density of copper powder / (g / cm³) 3 M is the total mass of copper powder and container (g); m is the mass of container (g); V is the volume of container (cm³). 3 .

[0030] The formula for calculating the current efficiency η in the copper electrowinning process is: ; In the formula: m is the mass of copper deposited on the cathode plate in g; I is the current in A; t is the energizing time in h; q is the electrochemical equivalent of copper, taken as 1.2193 g / (A•h); n is the number of plates connected in series.

[0031] The formula for calculating the energy consumption W of copper electrowinning is: ; In the formula: V is the average cell voltage / V; W is the energy consumption / (kWh / t•Zn).

[0032] This invention utilizes cyclic voltammetry (CV) to determine the nucleation overpotential (NOP) of copper, plotting the potential against a Hg / Hg₂SO₄ reference electrode. X-ray diffraction (XRD) is used to determine the crystal orientation, and based on the XRD results, the grain size is calculated using the Scheele formula, as follows: ; In the formula: D is the average size of the grains / nm; K is the shape constant, usually taken as about 0.9; λ is the X-ray wavelength, usually the Cu-Kα line (0.15418 nm); β is the full width at half maximum (FWHM) of the X-ray diffraction peak; θ0 is the diffraction angle.

[0033] The morphology and grain size distribution of the copper deposit were analyzed using scanning electron microscopy (SEM) and laser particle size analyzer.

[0034] The electrodeposition process of the present invention will be further illustrated by the following specific embodiments.

[0035] The experimental equipment and materials used in this invention embodiment are as follows: polypropylene electrodeposition cell (temperature tolerance range -20-120℃), intelligent constant voltage power supply (0-15V / 0-10A), liquid delivery control mechanism (channel inner diameter 6.4mm, flow rate 70.07mL / min, rotation speed 25rpm), ultrasonic generator (frequency 40kHz, power adjustment range 0-100W), Hall effect flowmeter (brass funnel, angle 60°), scanning electron microscope (SEM), laser particle size analyzer, electronic balance (accuracy 0.1mg). Other materials include Pb-Sn-Ca anode plate, 316L stainless steel cathode plate, CuSO4•5H2O (analytical grade), H2SO4 (analytical grade), sodium dodecylbenzenesulfonate (SDBS, analytical grade), polyvinylpyrrolidone (PVP, analytical grade), and deionized water.

[0036] Example 1: The specific implementation process of the electrodeposition method in this example is as follows: (1) Place the anode plates 9 sequentially into the corresponding limiting slots of the electrodeposition cell 7; configure the composition as Cu 2+A pretreatment solution with a concentration of 8 g / L and an H2SO4 concentration of 120 g / L was injected into electrodeposition cell 7. The electrodeposition apparatus was started at a temperature of 25°C and a current density of 1200 A / m. 2 The anode plate was activated for 24 hours under the specified conditions. After activation, the anode plate was removed and rinsed lightly with deionized water, revealing a uniform and dense PbO2 film on its surface.

[0037] (2) The cathode plate and anode plate are arranged alternately in the electrodeposition cell; Cu is prepared. 2+ A copper sulfate electrodeposition solution with a concentration of 8 g / L and an H2SO4 concentration of 120 g / L was prepared. During the electrodeposition process, the concentration of the copper sulfate electrodeposition solution in electrodeposition cell 7 was maintained in a dynamic equilibrium.

[0038] (3) Start the power supply of the electrodeposition cell 7 and the ultrasonic generator connected to the non-contact ultrasonic transducer 8, and set the ultrasonic frequency to 40kHz, ultrasonic power to 14W, electrodeposition cell temperature to 50℃, and current density to 1200A / m. 2 Under the specified conditions, the ultrasonic electrodeposition process lasted for 30 minutes. After electrodeposition, the electrodeposited copper powder was collected and its loose packing density was recorded. This invention relates to the determination of the loose packing density of copper powder and the surface morphology of copper powder deposition. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were applied to investigate the polarization behavior during the electrodeposition process.

[0039] Example 2: The difference from Example 1 is that the copper sulfate solution prepared in this example is supplemented with 0.5 g / L SDBS and 1.5 g / L PVP additives, and is enhanced by 14W ultrasonic treatment. Other electrodeposition conditions and steps are the same.

[0040] Comparative Example 1: The difference from Example 1 is that ultrasonic enhancement treatment is not used in this example, but the other electrodeposition conditions and steps are the same.

[0041] Comparative Example 2: The difference from Example 2 is that ultrasonic enhancement treatment is not used in this example, but the other electrodeposition conditions and steps are the same.

[0042] After electrodeposition, the cathode plate was removed, powder was scraped off, filtered, dried, and weighed to obtain precipitated copper powder. The bulk density of the copper powder corresponding to Examples 1-2 and Comparative Examples 1-2 was measured (e.g., ...). Figure 2 (as shown), SEM diagram (e.g.) Figure 3 As shown), LSV test (as shown) Figure 4 (as shown) and laser force analyzer test (such as) Figure 5 (As shown).

[0043] Figure 2 These are bar charts showing the loose bulk density of Embodiments 1-2 and Comparative Examples 1-2 of the present invention; Figure 2It can be seen that the bulk density of Example 1 (basal electrolyte + 14W ultrasound) is 0.569 g / cm³. 3 The bulk density of Comparative Example 1 (basal electrolyte + 0W sonication) was 0.871 g / cm³. 3 The bulk density of Example 2 (composite additive + 14W ultrasound) was 0.76 g / cm³. 3 The bulk density of Comparative Example 2 (composite additive + 0W ultrasound) was 0.89 g / cm³. 3 The results showed that the application of an ultrasonic field could significantly reduce the loose packing density of copper powder, and the synergistic effect of the composite additive and ultrasound further optimized the control effect of loose packing density.

[0044] Figure 3 The images shown are SEM images of copper powder from Examples 1-2 and Comparative Examples 1-2 of this invention; the morphology of the copper powder from Example 1 is as follows. Figure 3 As shown in (a), the prepared copper powder has a relatively uniform morphology, with a robust main trunk and good suppression of secondary dendrites, and a concentrated particle distribution, indicating that the powder morphology has been optimized. The morphology of the copper powder in Comparative Example 1 is as follows. Figure 3 As shown in (b), the prepared copper powder crystals have fine main trunks, exhibiting highly directional growth characteristics, forming a slender, multi-level branched dendritic structure, and the particles are relatively coarse. The morphology of the copper powder in Example 2 is as follows. Figure 3 As shown in (c), the prepared copper powder exhibits enhanced mass transfer at the electrode interface due to the ultrasonic flow effect, resulting in more uniform adsorption and more complete action. The morphology of the copper powder is further refined, the dendritic structure is significantly controlled, and the particle size is significantly reduced. The morphology of the copper powder in Comparative Example 2 is shown below. Figure 3 As shown in (d), the dendritic structure is relatively short, maintaining the basic framework, but the excessive branching of secondary dendrites is controlled.

[0045] Figure 4 Linear scanning voltammetry (LSV) plots of the copper powder deposition process in Examples 1-2 and Comparative Examples 1-2 of this invention are shown to investigate the polarization behavior during the electrodeposition process in Examples 1-2 and Comparative Examples 1-2. Figure 4 (a) Corresponding to Example 1 and Comparative Example 1, as the ultrasonic power increased from 0W to 14W, the linear scanning voltammetry further showed that the limiting diffusion current density under ultrasonic action increased significantly, and the diffusion control onset potential was delayed from -0.61V to -0.66V, indicating that the ultrasonic enhanced the mass transfer process, delayed the appearance of the diffusion control stage, and enabled electrodeposition to maintain good reaction kinetics over a wider potential range. Figure 4(b) In the same way as Example 2 and Comparative Example 2, after adding 0.5 g / L sodium dodecylbenzenesulfonate (SDBS) and 1.5 g / L polyvinylpyrrolidone (PVP), as the ultrasonic power increased from 0 W to 14 W, the polarization of the LSV curve intensified (the absolute value of the current density decreased), and the overpotential decreased to -96.84 mV, indicating that the kinetic resistance increased. This was mainly attributed to the ultrasonic cavitation effect stripping away the excessive PVP molecules adsorbed on the nucleus surface, exposing more highly active growth sites, dispersing the nucleus growth position, and thus enhancing the anisotropic growth of the nucleus, ultimately forming a loose dendritic morphology, corresponding to the lowest bulk density.

[0046] Figure 5 The particle size analysis diagrams are for copper powder in Examples 1-2 and Comparative Examples 1-2 of this invention; the particle size analysis of Comparative Example 1 is as follows. Figure 5 As shown in (a), D is formed. 10 =4.48μm, D 50 =12.47μm, D 90 Dendritic hierarchical aggregates with a particle size of 25.26 μm exhibit a broadly dispersed particle size distribution. Particle size analysis of Example 1 is as follows: Figure 5 As shown in (b), copper powder is refined to D in an ultrasonic field. 50 =6.29μm, and the intensity of the single peak in the volume distribution curve increased. Through the acoustic cavitation effect under ultrasonic treatment, the concentration of the particle size distribution was also improved. The particle size distribution of Comparative Example 2 is as follows: Figure 5 As shown in (c), the median particle size D of the copper powder 50 =13.62μm, where D 10 =5.72μm, D 90 =26.58μm, span value is approximately 1.53, exhibiting a moderately wide particle size distribution, indicating that the composite additive system has a certain regulatory effect on particle size uniformity. Particle size analysis of Example 2 is as follows: Figure 5 As shown in (d), the feature size D 10 =3.11μm, D 50 =11.64μm, D 90 =26.44μm. The copper powder in this system is mainly composed of fine particles, without excessive aggregation of large particles. Combined with its regular dendritic morphology, it proves that the application of ultrasonic technology has achieved directional control of fine particles.

[0047] This invention achieves precise control and morphology optimization of copper powder's loose packing density through the synergistic effects of anodic pretreatment activation, ultrasonic field enhancement, and composite additives. The cavitation effect of the ultrasonic field synergistically enhances the stability of anodic activation, significantly reducing the loose packing density of copper powder and improving particle morphology and flowability. The electrodeposition apparatus of this invention can integrate anodic pretreatment activation, ultrasonic field enhancement, and copper electrodeposition, achieving a high degree of automation. It enables efficient preparation of pretreatment solutions and copper sulfate electrodeposition solutions, and maintains the circulation of the electrodeposition solution during copper electrodeposition, achieving precise control and morphology optimization of copper powder's loose packing density, thus improving the stability and consistency of copper powder production. The electrodeposition apparatus is rationally designed, integrating multiple functions such as automatic filling, constant temperature stirring, ultrasonic enhancement, and solution circulation. The automatic filling mechanism enables quantitative dispensing of chemical materials and additives. The non-contact ultrasonic transducer provides a uniform ultrasonic field for the electrodeposition cell. The liquid delivery control mechanism, along with the inlet and return pipes, ensures stable composition of the electrodeposition solution in the electrodeposition cell. The overall structure of this apparatus is convenient to operate, has a wide range of applications, and effectively ensures consistent product quality.

[0048] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using an external field-enhanced electrodeposition method, characterized in that, include: An automatic filling thermostatic mixing tank (1) is provided with a mixing container (13) and a stirrer (14) is provided in the mixing container (13); at least one automatic filling mechanism (2) is provided on the top of the automatic filling thermostatic mixing tank (1), and each automatic filling mechanism (2) is connected to the mixing container (13) through a material conveying pipe (16); an inlet pipe (5) and a return pipe (6) are respectively provided on both sides of the automatic filling thermostatic mixing tank (1) to connect the mixing container (13) and the electrowinning tank (7), and both the inlet pipe (5) and the return pipe (6) are equipped with a liquid conveying control mechanism (15) to control the liquid flow rate; Electrolytic cell (7) has holes at both ends for connecting liquid inlet pipe (5) and liquid return pipe (6), and multiple limiting grooves are provided at equal intervals on the inner side wall of the electrolytic cell (7). An anode plate (9) and a cathode plate (10) are provided at intervals in the limiting grooves. A combined non-contact ultrasonic transducer (8) is attached to the bottom of the electrolytic cell (7).

2. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the field-enhanced electrodeposition method according to claim 1, characterized in that, The automatic filling mechanism (2) includes a mounting base (201) and a dust cover (202) disposed on the mounting base (201). The dust cover (202) is provided with a pressure-sensitive spring assembly, and a material flow channel (209) is formed between the pressure-sensitive spring assembly and the inner wall of the dust cover (202). The pressure-sensitive spring assembly includes a tapered pressure-sensitive end (203), a malleable spring wall (204), an M-shaped spring assembly (205), a hollow disc (206), and a triangular support base (207); the malleable spring wall (204) is arranged circumferentially between the tapered pressure-sensitive end (203) and the hollow disc (206), and an M-shaped spring assembly (205) connecting the tapered pressure-sensitive end (203) and the hollow disc (206) is arranged on the inner side of the malleable spring wall (204); A triangular support base (207) is provided on the lower circumference of the hollow disc (206). The legs of the triangular support base (207) are connected to the inner wall of the dust cover (202). A sealing ring (208) is provided at the lower part of the triangular support base (207) to connect the dust cover (202) and the mounting base (201). One end of the material conveying pipe (16) is inserted into the sealing ring (208).

3. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the field-enhanced electrodeposition method according to claim 1, characterized in that, The automatic filling constant temperature mixing tank (1) is provided with an integral or separate mixing chamber (101) and an installation chamber (102) arranged vertically and vertically. The mixing container (13) and the liquid conveying control mechanism (15) are respectively arranged in the mixing chamber (101). The side wall of the mixing container (13) is provided with holes for the liquid inlet pipe (5) and the liquid return pipe (6) to be inserted. The automatic filling mechanism (2) is respectively arranged at the top of the installation chamber (102), and the material conveying pipe (16) is arranged in the installation chamber (102).

4. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the external field enhanced electrodeposition method according to claim 3, characterized in that, The automatic filling constant temperature mixing tank (1) is provided with a control panel (3) on the front side of the installation chamber (102). The control panel (3) is provided with control buttons for controlling the opening and closing of the stirrer (14) and the temperature control base (17), as well as a temperature digital display screen (11) and a stirring speed digital display screen (12). The automatic filling constant temperature mixing tank (1) is provided with a transparent panel (4) on the front side of the mixing chamber (101), and the mixing container (13) is provided on the back side of the transparent panel (4).

5. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the field-enhanced electrodeposition method according to claim 3, characterized in that, The liquid delivery control mechanism (15) includes two sets of control pipes (5) and return pipes (6) respectively, which are respectively set on both sides of the stirring container (13); The liquid delivery control mechanism (15) includes a longitudinally arranged conical base plate (151). An active roller (152) is arranged at the center of the cone top of the conical base plate (151). The active roller (152) is arranged at the center of the triangular curved arm (153). Locking rollers (154) are arranged at both ends of the curved arm (153). A locking stationary roller (155) is arranged at the outer edge of the upper end of the conical base plate (151) corresponding to the locking roller (154). The liquid inlet pipe (5) and the liquid return pipe (6) pass through the channel formed between the locking stationary roller (155), the active roller (152), and the locking roller (154). The liquid flow rate is adjusted by driving the curved arm (153) to rotate and drive the locking roller (154) to rotate along the conical base plate (151) and cooperate with the locking stationary roller (155).

6. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the field-enhanced electrodeposition method according to claim 1, characterized in that, The mixing container (13) is provided with a temperature control base (17) at the lower end, and the mixing container (13) is provided with an opening baffle for the material conveying pipe (16) to be inserted at the top. The agitator (14) includes a stirring rod provided in the mixing container and a stirring paddle provided at its lower end.

7. The electrodeposition apparatus for controlling the loose packing density and morphology of copper powder using the external field enhanced electrodeposition method according to claim 1, characterized in that, The anode plate (9) is a Pb-Sn-Ca alloy plate, and the cathode plate (10) is a 316L stainless steel plate.

8. A method for electrodeposition to enhance the loose packing density and morphology of copper powder using an external field, characterized in that, Using the electrodeposition apparatus as described in any one of claims 1-7, the steps include: Step 1: Place the anode plates (9) sequentially into the corresponding limiting slots of the electrodeposition tank (7); add the material into the stirring container through the automatic filling mechanism (2), and prepare a pretreatment solution in the stirring container (13), the composition of which is Cu. 2+ The concentration of H2SO4 is 8 g / L and the concentration of H2SO4 is 120 g / L. The pretreatment solution prepared in the stirring container (13) is injected into the electrodeposition tank (7) through the liquid inlet pipe (5) and the liquid delivery control mechanism (15). The electrodeposition device is started at a temperature of 25°C and a current density of 1200 A / m. 2 The anode plate was activated for 24 hours under certain conditions, resulting in a uniform and dense lead dioxide coating on its surface. Step 2: Discharge the pretreatment solution stored in the electrodeposition tank (7); arrange the cathode plate and anode plate alternately in the electrodeposition tank; control the automatic filling mechanism (2) to supply Cu solution to the stirring container (13) through the material conveying pipe (16). 2+ A copper sulfate electrodeposition solution with a concentration of 8 g / L, H2SO4 concentration of 120 g / L, SDBS concentration of 0.5 g / L, and PVP concentration of 1.5 g / L was prepared. During the electrodeposition process, the concentration of the copper sulfate electrodeposition solution in the electrodeposition tank (7) was maintained in a dynamic balance by adjusting the opening of the liquid transport control mechanism (15) connected to the inlet pipe (5) and the return pipe (6). Step 3: Start the power supply of the electrodeposition cell (7) and the ultrasonic generator connected to the non-contact ultrasonic transducer (8), with an ultrasonic frequency of 40kHz, ultrasonic power of 10-20W, electrodeposition cell temperature of 50-52℃, and current density of 1200A / m. 2 Under the specified conditions, the ultrasonic electrowinning process was carried out for 30 minutes, and the electrowinning copper powder was collected and the loose packing density was recorded.

9. The electrodeposition method for externally enhanced control of the loose packing density and morphology of copper powder according to claim 8, characterized in that, The electrodeposition cell (7) mentioned in step 3 is made of polypropylene material and has a temperature tolerance range of -20-120℃. The electrodeposition cell (7) is powered by an intelligent constant voltage power supply with a power supply voltage of 0-15V and a power supply current of 0-10A.

10. The electrodeposition method for externally enhanced control of the loose packing density and morphology of copper powder according to claim 8, characterized in that, In step 3, a Hall effect flowmeter is used to measure the loose bulk density of copper powder. The funnel and density cup of the Hall effect flowmeter are made of brass, and the funnel angle is 60°. The formula for calculating the loose bulk density is: ρ=(Mm) / V; Where: ρ is the loose density of copper powder / (g / cm³) 3 M is the total mass of copper powder and container (g); m is the mass of container (g); V is the volume of container (cm³). 3 .

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