A method for preparing micrometer copper powder

Abstract

The application belongs to the field of metal powder preparation, and particularly relates to a preparation method of micron copper powder, which comprises the following steps: preparing copper powder by reducing copper salt solution through a reducing agent, and adding a dispersing agent, a complexing agent and an additive in the process of reduction to effectively prevent the agglomeration between particles. The application provides a simple, economical and reliable preparation method of micron copper powder, and micron copper powder is prepared in an aqueous solvent, so that the preparation cost is reduced. The particle size of the prepared copper powder is uniform, and the average particle size is about 3 microns. The yield of the copper powder is more than 95%, the purity is high, the specific resistance is low, and the copper powder has good conductivity.

Description

Technical Field

[0001] This invention belongs to the field of metal powder preparation, specifically relating to a method for preparing micron-sized copper powder. Background Technology

[0002] Copper powder, as an important industrial raw material, is widely used in many fields such as electronics and chemicals. With the advancement of science and technology and the development of industry, higher requirements have been put forward for the quality, particle size distribution, purity and production cost of copper powder.

[0003] Currently, the main methods for producing copper powder include electrolysis, water atomization, oxidation-reduction, and hydrometallurgy. However, in the process of preparing copper powder by reduction, the controllable synthesis of nano- or micron-sized particles, the selection of additives, and the control of reaction conditions remain a major challenge.

[0004] Ammonium benzoate can be used as a corrosion inhibitor in metal surface treatment and electroplating processes, forming a protective film on the metal surface to prevent metal oxidation. In the electroplating process, ammonium benzoate is used as an additive to improve the stability of the electroplating solution. In this invention, ammonium benzoate is added during the reduction method to prepare metal powder. Ammonium benzoate acts as an auxiliary agent, and through its ratio with dispersant, complexing agent, and reducing agent and the reaction conditions, it interacts to obtain conductive copper powder with high purity and good performance. Summary of the Invention

[0005] This invention provides a method for preparing micron-sized copper powder. During the reduction process, a dispersant, a complexing agent, and an auxiliary agent are added. By controlling the reaction conditions and proportions, micron-sized copper powder with high purity and good conductivity is obtained.

[0006] The technical solution of the present invention is as follows: a method for preparing micron-sized copper powder, comprising,

[0007] Step 1: Mix a measured amount of copper salt, complexing agent, and solvent, and heat to mix evenly to obtain solution A. The complexing agent forms a copper-ammonia complex with the copper ions in the copper salt solution. The formation of the stable complex helps to prevent the copper ions from reacting with hydroxide ions to form copper hydroxide precipitate, thereby avoiding the formation of precipitate. At the same time, it helps to control the particle size and morphology of copper powder and improve the dispersibility of copper powder in solution.

[0008] Step 2: Mix the reducing agent, complexing agent, dispersant, solvent and auxiliary agent, and heat to mix evenly to obtain solution B; pre-mix the reducing agent, complexing agent, dispersant, solvent and auxiliary agent evenly to provide a stable environment for the subsequent reduction reaction. Uniform reaction conditions help control the particle size distribution of copper powder and further enhance the dispersibility of copper powder.

[0009] Step 3: Mix solution A and solution B evenly, heat to react, filter, wash with water and alcohol, and grind to obtain micron-sized copper powder;

[0010] The additive is ammonium benzoate.

[0011] In step one, the copper salt is one or more of anhydrous copper sulfate, copper sulfate pentahydrate, copper nitrate, and copper chloride dihydrate.

[0012] The solvent in step one is one or more of distilled water and deionized water.

[0013] The concentration of solution A is 120–500 g / L; the heating temperature in step one is 50–70 °C, and the heating time is 0.5–2 h.

[0014] The reducing agent in step two is one or more of potassium borohydride, ascorbic acid, and sodium hypophosphite.

[0015] The complexing agent is ammonia water, and the ratio of the mass of the copper salt to the volume of the complexing agent is 1g:(0.5mL~5mL).

[0016] The dispersant in step two is one or more of polyvinylpyrrolidone K15, polyvinylpyrrolidone K30, polyvinylpyrrolidone K60, and cyclodextrin.

[0017] The mass ratio of the copper salt, reducing agent, and dispersant is 1:(0.5-2):(1-4.2).

[0018] The mass ratio of the copper salt to ammonium benzoate is 1:0.06 to 0.125.

[0019] In step two, the heating temperature is 50–70°C and the heating time is 0.5–2 hours; in step three, the heating temperature is 80–110°C and the heating time is 0.5–3 hours.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. In this invention, a dispersant is added during the reduction process. The dispersant can effectively reduce the interaction force between copper powder particles and prevent agglomeration, thereby obtaining a copper powder product with uniform particle size distribution and good dispersibility. It can also improve the surface properties of copper powder, which helps to enhance the activity and reactivity of copper powder in subsequent applications.

[0022] 2. In this invention, a complexing agent is added during the reduction process. The complexing agent can form a stable complex with impurity ions in the solution, thereby effectively removing impurities; it can also affect the reduction rate of copper ions and the growth of grains.

[0023] 3. In this invention, an auxiliary agent is added during the reduction process. The auxiliary agent is ammonium benzoate. During the reduction process, ammonium benzoate can inhibit the growth of crystal nuclei to a certain extent through adsorption, thus preventing the particles from becoming too large. Ammonium benzoate can form a protective film on the surface of copper powder particles. Together with the dispersant, it can more effectively prevent the agglomeration between particles and prepare copper particles with uniform particle size distribution.

[0024] 4. This invention prepares micron-sized copper powder in an aqueous solvent, which reduces the preparation cost. The prepared copper powder has a uniform particle size, averaging around 3 μm, a copper powder yield of over 92%, and high purity. It also exhibits low resistivity and good electrical conductivity. Attached Figure Description

[0025] Figure 1 This is a scanning electron microscope image of copper powder. Detailed Implementation

[0026] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0027] Example 1

[0028] Preparation of the copper salt solution to be reduced: Weigh 160g of anhydrous copper sulfate and 150mL of ammonia water, dissolve them in 600mL of deionized water, and stir at 60℃ for 1h.

[0029] Preparation of reducing agent solution: Weigh 125g sodium hypophosphite, 150mL ammonia water, 300g cyclodextrin and 15g ammonium benzoate, dissolve in 2400mL deionized water, and stir at 60℃ for 1h.

[0030] The copper salt solution to be reduced and the reducing agent solution were mixed together after stirring. The reaction temperature was controlled at 95℃ and the reaction time was 1.5h. After the reaction was completed, the mixture was allowed to stand and precipitate.

[0031] After complete precipitation, the supernatant was poured off, deionized water was added, and the mixture was stirred and allowed to stand to precipitate. This process was repeated 6 times. Then, anhydrous ethanol was added, and the process was repeated twice. The obtained product was dried in a vacuum oven at 55°C for 12 hours. After crushing and grinding, pure micron-sized copper powder was obtained. The scanning electron microscope image of the micron-sized copper powder is shown below. Figure 1 As shown.

[0032] Example 2

[0033] Preparation of the copper salt solution to be reduced: Weigh 160g of anhydrous copper sulfate and 150mL of ammonia water, dissolve them in 600mL of deionized water, and stir at 60℃ for 1h.

[0034] Preparation of reducing agent solution: Weigh 200g ascorbic acid, 150mL ammonia water, 250g polyvinylpyrrolidone K30 and 18g ammonium benzoate, dissolve in 2400mL deionized water, and stir at 60℃ for 1h.

[0035] The copper salt solution to be reduced and the reducing agent solution were mixed together after stirring. The reaction temperature was controlled at 90℃ and the reaction time was 2 hours. After the reaction was completed, the mixture was allowed to stand and precipitate.

[0036] After complete precipitation, the supernatant was poured off, deionized water was added, the mixture was stirred and allowed to stand to precipitate. This process was repeated 6 times. Then anhydrous ethanol was added and the process was repeated 2 times. The obtained material was placed in a vacuum oven at 55°C and dried for 12 hours. After crushing and grinding, pure micron-sized copper powder was obtained.

[0037] Example 3

[0038] Preparation of the copper salt solution to be reduced: Weigh 188g of copper nitrate and 300mL of ammonia water, dissolve them in 600mL of deionized water, and stir at 60℃ for 0.5h.

[0039] Preparation of reducing agent solution: Weigh 250g ascorbic acid, 300mL ammonia water, 200g polyvinylpyrrolidone K30 and 10g ammonium benzoate, dissolve in 2400mL deionized water, and stir at 60℃ for 0.5h.

[0040] The copper salt solution to be reduced and the reducing agent solution were mixed together after stirring. The reaction temperature was controlled at 100℃ and the reaction time was 0.5h. After the reaction was completed, the mixture was allowed to stand and precipitate.

[0041] After complete precipitation, the supernatant was poured off, deionized water was added, the mixture was stirred and allowed to stand to precipitate. This process was repeated 6 times. Then anhydrous ethanol was added and the process was repeated 2 times. The obtained material was placed in a vacuum oven at 55°C and dried for 12 hours. After crushing and grinding, pure micron-sized copper powder was obtained.

[0042] Comparative Example

[0043] Preparation of the copper salt solution to be reduced: Weigh 160g of anhydrous copper sulfate and 150mL of ammonia water, dissolve them in 600mL of deionized water, and stir at 60℃ for 1h.

[0044] Preparation of reducing agent solution: Weigh 125g sodium hypophosphite, 150mL ammonia water, and 300g cyclodextrin, dissolve them in 2400mL deionized water, and stir at 60℃ for 1h.

[0045] The copper salt solution to be reduced and the reducing agent solution were mixed together after stirring. The reaction temperature was controlled at 95℃ and the reaction time was 1.5h. After the reaction was completed, the mixture was allowed to stand and precipitate.

[0046] After complete precipitation, the supernatant was poured off, deionized water was added, the mixture was stirred and allowed to stand to precipitate. This process was repeated 6 times. Then anhydrous ethanol was added and the process was repeated 2 times. The obtained material was placed in a vacuum oven at 55°C and dried for 12 hours. After crushing and grinding, pure micron-sized copper powder was obtained.

[0047] The yield calculation formula is shown below, where m1 is the actual copper powder output and m2 is the theoretical copper powder output.

[0048]

[0049] The copper powders of Examples 1-3 and the comparative examples were characterized and tested, as shown in Table 1.

[0050] Table 1

[0051]

Claims

1. A method for preparing a microcopper powder, characterized by, The application relates to a preparation method of micron copper powder. Step one: a certain amount of copper salt, complexing agent and solvent are mixed and heated to be uniformly mixed to obtain solution A; Step two: a reducing agent, a complexing agent, a dispersing agent, a solvent and an auxiliary agent are mixed and heated to be uniformly mixed to obtain solution B; Step three: solution A and solution B are uniformly mixed, heated, filtered, washed with water and alcohol, and ground to obtain micron copper powder; The auxiliary agent is ammonium benzoate; The dispersing agent in step two is one or more of polyvinylpyrrolidone K15, polyvinylpyrrolidone K30, polyvinylpyrrolidone K60 and cyclodextrin; The mass ratio of the copper salt, the reducing agent and the dispersing agent is 1: (0.5-2): (1-4.2); The mass ratio of the copper salt and ammonium benzoate is 1: 0.06-0.125; The heating temperature in step three is 80-110 DEG C, and the heating time is 0.5-3 h.

2. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The copper salt in step one is one or more of anhydrous copper sulfate, copper sulfate pentahydrate, copper nitrate and cupric chloride dihydrate.

3. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The solvent is one or more of distilled water and deionized water.

4. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The concentration of solution A is 120-500 g / L; the heating temperature in step one is 50-70 DEG C, and the heating time is 0.5-2 h.

5. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The reducing agent in step two is one or more of potassium borohydride, ascorbic acid and sodium hypophosphite.

6. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The complexing agent is ammonia water, and the mass ratio of the copper salt to the complexing agent is 1 g: (0.5 mL-5 mL).

7. The method for preparing micron-sized copper powder according to claim 1, characterized in that: The heating temperature in step two is 50-70 DEG C, and the heating time is 0.5-2 h.

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