Spherical copper powder and preparation method thereof

Abstract

The invention relates to spherical copper powder and a preparation method thereof. The preparation method comprises the following steps: preparing a copper salt dispersion liquid containing a copper salt and a dispersing agent, a first reduction liquid and a second reduction liquid; a first reducing solution is added into the copper salt dispersion liquid, a reaction is carried out at a first preset temperature for a first preset time, a reaction liquid is obtained, and the first preset time is 0.5-1 h; a second reduction solution is added into the reaction solution, a reaction is carried out at a second preset temperature for a second preset time, copper powder slurry is obtained, and the second preset time is 1-2 h; the spherical copper powder with large particle size and high sphericity is separated from the copper powder slurry, so that the high-sphericity copper powder with good dispersity can be prepared by adopting a liquid phase reduction method, taking copper salt as a raw material, adding a dispersing agent, mixing and carrying out two-step reduction, the preparation process is simple, and the preparation cost is low. And the high-sphericity copper powder has the characteristics of large particle size, relatively wide distribution, high sphericity and the like, is beneficial to lap joint of a conductive network, and has a good application scene in the field of electricity.

Description

Technical Field

[0001] The present application relates to the technical field of metal powder preparation, and in particular to a spherical copper powder and a preparation method thereof. Background Art

[0002] With the rapid development of the electronic information industry, precious metal electronic paste, especially metal silver powder, has become one of the key materials for the production of various electronic components. However, compared with precious metal silver, micro-nano copper powder is expected to become a substitute for precious metal materials due to its high electrical and thermal conductivity, low electrochemical migration behavior, strong solderability and low price. It has important economic value in the fields of military industry, shipbuilding, aerospace and microelectronics, and is one of the future development directions of electronic paste.

[0003] In the field of electronic pastes, the selection of conductive metal materials must have good dispersibility, sphericity and oxidation resistance to ensure that the paste has good rheological properties, conductivity and sintering properties. However, copper powders currently prepared by physical and chemical methods generally have problems such as low sphericity, large shape differences and difficulty in preparing large particle sizes.

[0004] Therefore, it is particularly important to study how to prepare copper powder with large particle size and high sphericity. Summary of the invention

[0005] The purpose of the present application is to provide a spherical copper powder and a preparation method thereof, so as to prepare a copper powder with large particle size and high sphericity, so as to be widely used in the fields of electronic paste, capacitor electrode, microelectronics, etc.

[0006] An embodiment of the present application provides a method for preparing spherical copper powder, which comprises: preparing a copper salt dispersion, a first reducing liquid and a second reducing liquid, wherein the copper salt dispersion comprises a copper salt and a dispersant, the first reducing liquid comprises a first reducing agent, and the second reducing liquid comprises a second reducing agent; adding the first reducing liquid to the copper salt dispersion, reacting at a first preset temperature for a first preset time to obtain a reaction liquid, wherein the first preset time is 0.5 to 1 hour; adding the second reducing liquid to the reaction liquid, reacting at a second preset temperature for a second preset time to obtain a copper powder slurry, wherein the second preset time is 1 to 2 hours; and separating the spherical copper powder from the copper powder slurry.

[0007] The concentration of the copper salt in the copper salt dispersion is 0.1-0.6 kg / L; the concentration of the first reducing agent in the first reducing solution is 0.1-0.4 kg / L; and the concentration of the second reducing agent in the second reducing solution is 0.05-0.2 kg / L.

[0008] The ratio of the mass of the dispersant in the copper salt dispersion to the mass of the copper salt in the copper salt dispersion is 1% to 10%.

[0009] The mass ratio of the first reducing agent in the first reducing solution to the mass ratio of the copper salt in the copper salt dispersion is 30% to 80%; the mass ratio of the second reducing agent in the second reducing solution to the mass ratio of the copper salt in the copper salt dispersion is 5% to 20%.

[0010] The method of preparing a copper salt dispersion includes: adding a dispersant to a copper salt solution and stirring the solution evenly, then adding a pH adjuster and adjusting the pH value to a preset value to obtain a copper salt dispersion, wherein the preset value is 8 to 13, and the pH adjuster includes at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid and sulfuric acid.

[0011] Among them, the first preset temperature is 50-90°C, and the second preset temperature is 50-90°C.

[0012] The copper salt includes at least one of copper sulfate, copper nitrate, copper chloride, copper acetate, copper lactate, copper oleate, copper citrate and copper tartrate; the dispersant includes at least one of hexadecyltrimethylammonium bromide, polyvinyl pyrrolidone, triethylhexyl phosphoric acid, sodium dodecyl sulfate and polyvinyl alcohol.

[0013] The first reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde; the second reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde.

[0014] The method of separating spherical copper powder from copper powder slurry includes: separating the copper powder slurry into solid and liquid, washing the separated solid, and drying the washed solid to obtain spherical copper powder.

[0015] The embodiment of the present application also provides a spherical copper powder, which is prepared by any of the above-mentioned methods for preparing spherical copper powder.

[0016] The spherical copper powder and the preparation method thereof provided by the present application are prepared by preparing a copper salt dispersion, a first reducing solution and a second reducing solution, wherein the copper salt dispersion comprises a copper salt and a dispersant, the first reducing solution comprises a first reducing agent, and the second reducing solution comprises a second reducing agent, then the first reducing solution is added to the copper salt dispersion, and the reaction is carried out at a first preset temperature for a first preset time to obtain a reaction solution, wherein the first preset time is 0.5 to 1 hour, then the second reducing solution is added to the reaction solution, and the reaction is carried out at a second preset temperature for a second preset time to obtain a copper powder slurry, wherein the second preset time is 1 to 2 hours, and then the spherical copper powder is separated from the copper powder slurry. The spherical copper powder has a large particle size and a high sphericity. Thus, by adopting a liquid phase reduction method, copper salt is used as a raw material, a dispersant is added and mixed, and a two-step reduction is performed to control the reaction speed, thereby preventing the problem of excessive copper crystal generation and too small particle size in the initial stage of the reaction due to excessive reaction speed. In addition, the presence of the dispersant not only allows copper atoms to grow uniformly and in the same direction on the surface of the crystal nucleus, but also prevents the copper powder from aggregating. Thus, high-sphericity copper powder with good dispersibility can be prepared. The preparation process is simple, and the high-sphericity copper powder has the characteristics of large particle size, wide distribution, high sphericity, etc., which is conducive to the overlapping of conductive networks and has good application scenarios in the electrical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0018] Figure 1 Schematic diagram of the process of preparing spherical copper powder provided in the embodiment of the present application;

[0019] Figure 2 This is a scanning electron microscope image of the spherical copper powder obtained by the preparation method of the spherical copper powder provided in Example 1 of the present application, magnified 5000 times;

[0020] Figure 3 This is a scanning electron microscope image of the spherical copper powder prepared by the preparation method of the spherical copper powder provided in Example 2 of the present application, magnified 5000 times. DETAILED DESCRIPTION

[0021] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0022] In the following description of the present application, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0023] In the following description of the present application, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0025] The following is a detailed description with reference to specific embodiments. It should be noted that the serial numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0026] See also Figure 1 , Figure 1 : is a schematic diagram of a process for preparing a spherical copper powder provided in an embodiment of the present application. The specific process of the process for preparing the spherical copper powder may be as follows:

[0027] Step S11. Prepare a copper salt dispersion, a first reducing solution and a second reducing solution, wherein the copper salt dispersion comprises a copper salt and a dispersant, the first reducing solution comprises a first reducing agent, and the second reducing solution comprises a second reducing agent.

[0028] In this embodiment, the concentration of the copper salt in the copper salt dispersion may be 0.1-0.6 kg / L. In some examples, the concentration of the copper salt in the copper salt dispersion may be specifically 0.2-0.4 kg / L, for example, 0.2 kg / L, 0.25 kg / L, 0.3 kg / L, 0.35 kg / L or 0.4 kg / L, etc. The concentration of the first reducing agent in the first reducing solution may be 0.1-0.4 kg / L, for example, 0.1 kg / L, 0.15 kg / L, 0.2 kg / L, 0.25 kg / L, 0.3 kg / L, 0.35 kg / L or 0.4 kg / L, etc. The concentration of the second reducing agent in the second reducing solution may be 0.05-0.2 kg / L, for example, 0.05 kg / L, 0.1 kg / L, 0.15 kg / L or 0.2 kg / L, etc.

[0029] The mass ratio of the dispersant in the copper salt dispersion to the mass ratio of the copper salt in the copper salt dispersion can be 1% to 10%, for example, it can be specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc. The mass ratio of the first reducing agent in the first reducing solution to the mass ratio of the copper salt in the copper salt dispersion can be 30% to 80%, for example, it can be specifically 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc. The mass ratio of the second reducing agent in the second reducing solution to the mass ratio of the copper salt in the copper salt dispersion can be 5% to 20%, for example, it can be specifically 5%, 10%, 15% or 20%, etc.

[0030] Specifically, the copper salt in the copper salt dispersion can be a soluble copper salt. In some examples, the copper salt in the copper salt dispersion can include at least one of copper sulfate, copper nitrate, copper chloride, copper acetate, copper lactate, copper oleate, copper citrate and copper tartrate. For example, it can be copper chloride (e.g., copper chloride pentahydrate), copper sulfate or copper nitrate, etc.

[0031] Specifically, the dispersant in the copper salt dispersion may include at least one of cetyltrimethylammonium bromide, polyvinyl pyrrolidone, triethylhexyl phosphoric acid, sodium lauryl sulfate and polyvinyl alcohol, for example, cetyltrimethylammonium bromide or triethylhexyl phosphoric acid.

[0032] Specifically, the first reducing agent in the first reducing solution may include at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde, for example, may specifically be ascorbic acid or glucose.

[0033] Specifically, the second reducing agent in the second reducing solution may include at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde, for example, may specifically be hydrazine hydrate.

[0034] Furthermore, during specific implementation, the first reducing agent in the first reducing liquid and the second reducing agent in the second reducing liquid may be the same or different.

[0035] In some embodiments, the copper salt dispersion can be obtained by adding a dispersant to a copper salt solution and stirring the solution to obtain a copper salt dispersion. The copper salt solution can refer to a copper salt aqueous solution.

[0036] Specifically, the pH value of the copper salt dispersion can be a preset value. In addition, the step of preparing the copper salt dispersion can include: adding a dispersant to the copper salt solution and stirring evenly, then adding a pH adjuster, adjusting the pH value to a preset value, and obtaining a copper salt dispersion. Among them, the preset value can be 8 to 13, for example, it can be specifically 8, 9, 10, 11, 12 or 13. The pH adjuster can include at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid and sulfuric acid, for example, it can be specifically sodium hydroxide.

[0037] In some examples, 1 kg of copper nitrate solid can be added to ultrapure water and stirred to dissolve to obtain a copper nitrate solution with a concentration of 0.2 kg / L. Then, 60 g of hexadecyltrimethylammonium bromide is added to the copper nitrate solution and stirred evenly to obtain a copper nitrate dispersion. Then, sodium hydroxide is added to the copper nitrate dispersion to adjust the pH value to 12, and a copper nitrate dispersion with a pH value of 12 (i.e., a copper salt dispersion) can be obtained.

[0038] In other examples, 1 kg of cupric chloride pentahydrate can be added to ultrapure water and stirred to dissolve to obtain a cupric chloride solution with a concentration of 0.2 kg / L. Then, 60 g of triethylhexyl phosphoric acid is added to the cupric chloride solution and stirred evenly to obtain a cupric chloride dispersion. Then, sodium hydroxide is added to the cupric chloride dispersion to adjust the pH value to 12, and a cupric chloride dispersion (i.e., a copper salt dispersion) with a pH value of 12 can be obtained.

[0039] In some embodiments, the first reducing solution may refer to a first reducing agent solution. In addition, the step of preparing the first reducing solution may include: adding a first reducing agent (eg, ascorbic acid or glucose) into ultrapure water, stirring and dissolving to obtain the first reducing solution.

[0040] In some examples, 700 g of ascorbic acid solid can be added as the first reducing agent into ultrapure water, and stirred to dissolve to obtain a first reducing agent solution (ie, a first reducing solution) with a concentration of 0.1 kg / L.

[0041] In other examples, 500 g of glucose can be added as the first reducing agent into ultrapure water, and stirred to dissolve to obtain a first reducing agent solution (ie, a first reducing solution) with a concentration of 0.3 kg / L.

[0042] In some embodiments, the second reducing solution may refer to a second reducing agent solution. In addition, the step of preparing the second reducing solution may include: adding a second reducing agent (eg, hydrazine hydrate) into ultrapure water, stirring and dissolving to obtain the second reducing solution.

[0043] In some examples, 80 g of hydrazine hydrate liquid can be added as the second reducing agent into ultrapure water, and stirred to dissolve to obtain a second reducing agent solution (ie, second reducing solution) with a concentration of 0.05 kg / L.

[0044] Step S12. Add the first reducing solution to the copper salt dispersion, and react at a first preset temperature for a first preset time to obtain a reaction solution, wherein the first preset time is 0.5 to 1 hour.

[0045] The first preset time may be 30 minutes, 40 minutes, 50 minutes or 1 hour, etc. The first preset temperature may be 50-90°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc.

[0046] Step S13. Add a second reducing solution to the reaction solution, and react at a second preset temperature for a second preset time to obtain a copper powder slurry, wherein the second preset time is 1 to 2 hours.

[0047] The second preset time may be 1h, 1h10min, 1h20min, 1h30min, 1h40min, 1h50min or 2h, etc. The second preset temperature may be 50-90°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C, etc.

[0048] In some embodiments, the reaction temperature in step S13 (i.e., the second preset temperature) and the reaction temperature in step S12 (i.e., the first preset temperature) may be the same, for example, both may be 85° C. The reaction time in step S13 (i.e., the second preset time) may be greater than the reaction time in step S12 (i.e., the first preset time) and the second preset time may be the same, for example, the first preset time and the second preset time may be 50 min and 1 h, respectively.

[0049] Exemplarily, the step S12 may include: adding the first reducing solution to the copper salt dispersion, stirring and reacting at 85° C. for 50 minutes to obtain a reaction solution. The step S13 may include: adding the second reducing solution to the copper salt dispersion, stirring and reacting at 85° C. for 1 hour to obtain a copper powder slurry.

[0050] Furthermore, it should be noted that, in the embodiment of the present application, by configuring the first reducing solution and the second reducing solution, the reduction is carried out in two steps, the reaction rate is controlled, and by adding a macromolecular dispersant, the crystal face growth can be controlled to prepare a copper powder with high sphericity. Moreover, the step-by-step reduction prevents the problem of the subsequent inability to grow into a large particle size due to the explosive nucleation of copper crystals, while the inhibitory effect of the dispersant on a specific crystal face avoids the problem of preferential growth of copper atoms and deterioration of sphericity, thereby finally forming a high sphericity copper powder with a large particle size and a wide distribution, which is conducive to the overlap of the conductive network and has a wide range of applications in the fields of electronic slurries, capacitor electrodes, and microelectronics.

[0051] Step S14: Separating spherical copper powder from the copper powder slurry.

[0052] It should be noted that the spherical copper powder obtained after the completion of the above step S14 has a large particle size and high sphericity, and thus has a wide range of applications in the fields of electronic pastes, capacitor electrodes, microelectronics, etc.

[0053] In some embodiments, the particle size distribution of the spherical copper powder obtained after the above step S14 is completed can be relatively wide, for example, can be between 0.5 μm and 7 μm.

[0054] In some embodiments, the above step S14 may include: separating the copper powder slurry from solid and liquid, washing the separated solid, and drying the washed solid to obtain spherical copper powder. The drying temperature may be 50 to 70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C. The drying time may be 90 to 150 minutes, for example, 90 minutes, 100 minutes, 110 minutes, 120 minutes, 130 minutes, 140 minutes or 150 minutes. Specifically, the step of separating the copper powder slurry from solid and liquid may include: separating the solid and liquid in the copper powder slurry by filtering. The step of washing the separated solid may include: washing the separated solid with ultrapure water.

[0055] Furthermore, in a specific implementation, the copper powder slurry can be filtered and the solid phase can be collected, and then the collected solid can be washed with ultrapure water, and the washed solid can be placed in a 60°C oven and dried for 120 minutes to obtain the target product (ie, the above-mentioned spherical copper powder).

[0056] It is to be understood that all raw materials used in the examples of the present application can be obtained commercially.

[0057] Furthermore, for ease of understanding, the present application is further described in detail below through two specific embodiments (ie, Embodiment 1 and Embodiment 2).

[0058] Example 1

[0059] In Example 1, the specific process of the preparation method of spherical copper powder can be as follows:

[0060] Step S21. preparing a copper salt dispersion, a first reducing solution and a second reducing solution, comprising: weighing 1 kg of copper nitrate solid to prepare a copper nitrate solution with a concentration of 0.2 kg / L, weighing 60 g of hexadecyltrimethylammonium bromide, adding it to the copper nitrate solution and stirring it evenly to obtain a copper nitrate dispersion, and then adding sodium hydroxide to the copper nitrate dispersion to adjust the pH value to 12 to obtain a copper salt dispersion; weighing 700 g of ascorbic acid solid to prepare a reducing agent solution with a concentration of 0.1 kg / L, stirring it evenly to obtain a first reducing solution; weighing 80 g of hydrazine hydrate liquid to prepare a reducing agent solution with a concentration of 0.05 kg / L, stirring it evenly to obtain a second reducing solution;

[0061] Step S22. Add the first reducing solution to the copper salt dispersion, stir and react at 85°C for 50 minutes, then add the second reducing solution, continue to stir and react at 85°C for 1 hour, and obtain a copper powder slurry after the reaction is completed;

[0062] Step S23. Filter the copper powder slurry and collect the solid phase, then wash the collected solid with ultrapure water, and bake the washed solid in an oven at 60° C. for 120 min to obtain the target product (ie, spherical copper powder A1).

[0063] Specifically, from the scanning electron microscope image of the spherical copper powder A1 ( Figure 2 As shown in the figure, the spherical copper powder A1 is a copper powder with large particle size and high sphericity, and its particle size distribution is wide and the shape difference is small.

[0064] Example 2

[0065] Step S31. preparing a copper salt dispersion, a first reducing solution and a second reducing solution, comprising: weighing 1 kg of cupric chloride pentahydrate to prepare a copper chloride solution with a concentration of 0.2 kg / L, weighing 60 g of triethylhexyl phosphoric acid, adding it to the copper chloride solution and stirring it evenly to obtain a copper chloride dispersion, and then adding sodium hydroxide to the copper chloride dispersion to adjust the pH value to 12 to obtain a copper salt dispersion; weighing 500 g of glucose to prepare a reducing agent solution with a concentration of 0.3 kg / L, stirring it evenly to obtain a first reducing solution; weighing 80 g of hydrazine hydrate liquid to prepare a reducing agent solution with a concentration of 0.05 kg / L, stirring it evenly to obtain a second reducing solution;

[0066] Step S32. Add the first reducing solution to the copper salt dispersion, stir and react at 85°C for 50 minutes, then add the second reducing solution, continue to stir and react at 85°C for 1 hour, and obtain a copper powder slurry after the reaction is completed;

[0067] Step S33. Filter the copper powder slurry and collect the solid phase, then wash the collected solid with ultrapure water, and bake the washed solid in an oven at 60°C for 120 minutes to obtain the target product (ie, spherical copper powder A2).

[0068] Specifically, from the scanning electron microscope image of the spherical copper powder A2 (such as Figure 3 As shown in the figure, the spherical copper powder A2 is a large-particle-size, high-sphericity copper powder, and its particle size distribution is wide and the shape difference is small.

[0069] Furthermore, by comparing the SEM images of the spherical copper powder A2 with the SEM images of the spherical copper powder A1, it can be seen that Figure 3 and Figure 2 It can be seen that in Example 2, the copper salt, dispersant and first reducing solution were changed, and the spherical copper powder A2 obtained still had a large particle size and high sphericity, but the particle size distribution was changed. It can be seen that the morphology and size of the spherical copper powder can be effectively regulated by changing the copper salt, dispersant and first reducing solution, and the regulation method is simple.

[0070] As can be seen from the above, the preparation method of spherical copper powder provided in this embodiment is by preparing a copper salt dispersion, a first reducing solution and a second reducing solution, wherein the copper salt dispersion includes a copper salt and a dispersant, the first reducing solution includes a first reducing agent, and the second reducing solution includes a second reducing agent, and then the first reducing solution is added to the copper salt dispersion, and the reaction is carried out at a first preset temperature for a first preset time to obtain a reaction solution, wherein the first preset time is 0.5 to 1h, and then the second reducing solution is added to the reaction solution, and the reaction is carried out at a second preset temperature for a second preset time to obtain a copper powder slurry, wherein the second preset time is 1 to 2h, and then the spherical copper powder is separated from the copper powder slurry. The spherical copper powder has a large particle size and a high sphericity. Thus, by adopting a liquid phase reduction method, copper salt is used as a raw material, a dispersant is added and mixed, and a two-step reduction is performed to control the reaction speed, thereby preventing the problem of excessive copper crystal generation and too small particle size in the initial stage of the reaction due to excessive reaction speed. In addition, the presence of the dispersant not only allows copper atoms to grow uniformly in the same direction on the surface of the crystal nucleus, but also prevents the copper powder from agglomerating. Thus, high-sphericity copper powder with good dispersibility can be prepared. The preparation process is simple, and the high-sphericity copper powder has the characteristics of large particle size, wide distribution, high sphericity, etc., which is conducive to the overlapping of conductive networks and has good application scenarios in the electrical field.

[0071] In order to better implement the preparation method of the spherical copper powder provided in the embodiment of the present application, the embodiment of the present application also provides a spherical copper powder (such as Figure 2 or Figure 3 As shown), the spherical copper powder is prepared by the preparation method of the spherical copper powder provided by any of the above embodiments.

[0072] Specifically, the spherical copper powder has a large particle size and high sphericity, that is, the spherical silver powder is a large particle size, high sphericity copper powder, and thus has a wide range of applications in electronic pastes, capacitor electrodes, microelectronics and other fields.

[0073] In some embodiments, the particle size distribution of the spherical copper powder may be relatively wide, for example, between 0.5 μm and 7 μm.

[0074] Furthermore, it should be noted that the spherical copper powder in the embodiment of the present application is prepared by adopting the preparation method of the spherical copper powder provided by any of the above embodiments, and therefore has all the same beneficial effects, which will not be described in detail in this embodiment.

[0075] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0076] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing spherical copper powder, characterized in that: include: Prepare a copper salt dispersion, a first reducing solution, and a second reducing solution, wherein the copper salt dispersion comprises a copper salt and a dispersant, the first reducing solution comprises a first reducing agent, and the second reducing solution comprises a second reducing agent; Add the first reducing solution to the copper salt dispersion, and react at a first preset temperature for a first preset time to obtain a reaction solution, wherein the first preset time is 0.5 to 1 hour; Add the second reducing solution to the reaction solution, and react at a second preset temperature for a second preset time to obtain a copper powder slurry, wherein the second preset time is 1 to 2 hours; Spherical copper powder is separated from the copper powder slurry.

2. The preparation method according to claim 1, characterized in that: The concentration of the copper salt in the copper salt dispersion is 0.1-0.6 kg / L; the concentration of the first reducing agent in the first reducing solution is 0.1-0.4 kg / L; and the concentration of the second reducing agent in the second reducing solution is 0.05-0.2 kg / L.

3. The preparation method according to claim 1, characterized in that: The ratio of the mass of the dispersant in the copper salt dispersion to the mass of the copper salt in the copper salt dispersion is 1% to 10%.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the first reducing agent in the first reducing solution to the mass ratio of the copper salt in the copper salt dispersion is 30% to 80%; the mass ratio of the second reducing agent in the second reducing solution to the mass ratio of the copper salt in the copper salt dispersion is 5% to 20%.

5. The preparation method according to claim 1, characterized in that: The copper salt dispersion is prepared, comprising: A dispersant is added to the copper salt solution and stirred evenly, and then a pH adjuster is added to adjust the pH value to a preset value to obtain the copper salt dispersion, wherein the preset value is 8 to 13, and the pH adjuster includes at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid and sulfuric acid.

6. The preparation method according to claim 1, characterized in that: The first preset temperature is 50-90°C, and the second preset temperature is 50-90°C.

7. The preparation method according to claim 1, characterized in that: The copper salt includes at least one of copper sulfate, copper nitrate, copper chloride, copper acetate, copper lactate, copper oleate, copper citrate and copper tartrate; the dispersant includes at least one of hexadecyltrimethylammonium bromide, polyvinyl pyrrolidone, triethylhexyl phosphoric acid, sodium dodecyl sulfate and polyvinyl alcohol.

8. The preparation method according to claim 1, characterized in that: The first reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde; the second reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde.

9. The preparation method according to claim 1, characterized in that: The step of separating spherical copper powder from the copper powder slurry comprises: The copper powder slurry is solid-liquid separated, the separated solid is washed, and the washed solid is dried to obtain spherical copper powder.

10. A spherical copper powder, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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