TWI661092B - Method for preparing copper particles - Google Patents

Abstract

A copper particle preparation method is mainly used to solve the problem that the conventional copper particle preparation method consumes time and cannot be continuously produced. The system includes: providing a copper-containing electrolyte, the copper-containing electrolyte is selected from the group consisting of a copper sulfate-containing solution and a copper chloride-containing solution, and the copper sulfate-containing solution contains a concentration of 0.037 ~ 3% w / v copper ion, the copper chloride-containing solution contains copper ions at a concentration of 0.037 to 1% w / v; an anode electrode and a cathode electrode are extended into the copper-containing electrolyte, and the anode electrode is an insoluble electrode; And applying an electric current to the anode electrode and the cathode electrode to electrolyze the copper-containing electrolyte, so that several copper particles are precipitated and deposited in the copper-containing electrolyte.

Description

Preparation method of copper particles

The invention relates to a method for preparing copper particles, in particular to a method for preparing copper particles that can be continuously produced and can produce copper particles with small particle size and uniform distribution.

Copper particles are widely used in industry, for example, copper particles can be blended as conductive materials, copper particles can be used as catalysts, etc. Therefore, the size of copper particles will affect the ability of copper particles to be used in the above applications. The effect exhibited is that the copper particles with a smaller particle size have a larger specific surface area and a higher reaction rate. Conversely, copper particles with a larger particle size have a smaller specific surface area and a lower reaction rate.

A conventional method for preparing copper particles is an electrolysis of an acidic copper-containing electrolyte under a current density operation of 1 to 30 A / dm ² , so that several copper particles can be precipitated on the surface of a cathode electrode and attached to the cathode electrode. On the surface of the cathode electrode, the particle size distribution of the copper particles prepared by the conventional copper particle preparation method is about 3 to 30 μm.

However, in the conventional copper particle preparation method, after the copper particles are formed, the copper particles will adhere to the surface of the cathode electrode, and the copper particles must be further collected from the surface of the cathode electrode. The cathode electrode must be removed and replaced in a timely manner, which affects the production efficiency of copper particles. In addition, the specifications of the copper particles obtained by the conventional copper particle preparation method are not uniform, and workers must perform size screening on the obtained copper particles, which increases the work cost.

In view of this, the conventional method for preparing copper particles does still need to be improved.

In order to solve the above problems, the present invention provides a method for preparing copper particles, which prevents copper particles from adhering to the surface of a cathode electrode after precipitation.

The invention also provides a method for preparing copper particles, which can prepare copper particles with small particle diameter and uniform particle diameter.

The method for preparing copper particles of the present invention comprises: providing a copper-containing electrolyte, the copper-containing electrolyte is selected from the group consisting of a copper sulfate-containing solution and a copper chloride-containing solution, and the copper sulfate-containing solution contains 0.037 ~ 3% w / v copper ion, the copper chloride-containing solution contains 0.037 ~ 1% w / v copper ion; an anode electrode and a cathode electrode are protruded into the copper-containing electrolyte, and the anode electrode is An insoluble electrode; and applying a current to the anode electrode and the cathode electrode to electrolyze the copper-containing electrolyte under a current density operation of 10 to 100 A / dm2, so that several copper particles are precipitated and deposited on the copper-containing electrolyte in.

According to this, in the copper particle preparation method of the present invention, the copper-containing electrolyte contains a proper proportion of copper sulfate, and the generated copper particles will not adhere to the cathode electrode after precipitating from the cathode electrode. The copper particles can be prepared quickly and conveniently, and the production time can be shortened and the production efficiency can be improved. In addition, the produced copper particles have the effect of smaller particle size and more uniform particle size.

Among them, the copper sulfate-containing solution having a copper ion concentration of 3% w / v or the copper chloride-containing solution having a copper ion concentration of 1% w / v is selected as the copper-containing electrolyte. In this way, it has the effect of preparing small-sized copper particles.

Wherein, the copper sulfate-containing solution having a copper ion concentration of 3% w / v and the copper chloride-containing solution having a copper ion concentration of 10% w / v were mixed as the copper-containing electrolyte, and the copper ion concentration was 10% The volume ratio of w / v of the copper chloride-containing solution to the copper-containing electrolyte is 2-10%. In this way, it has the effect of making the particle size of the copper particles produced by the copper particle preparation method of the present invention less than 2 μm.

Wherein, a sulfuric acid solution is added to the copper-containing electrolyte before electrolysis, so that the The pH value of the copper-containing electrolyte is less than 3. In this way, it has the effect of improving current efficiency.

Among them, a titanium-plated iridium oxide electrode is selected as the anode electrode. In this way, it has the effect of improving the stability and durability of the anode.

Among them, a titanium-plated iridium oxide electrode is selected as the cathode electrode. In this way, it has the effect of improving the stability and durability of the cathode.

Among them, under a current density operation of 21 A / dm ² , several copper particles were precipitated and deposited in the copper-containing electrolyte. In this way, for the copper-containing electrolyte having a copper ion concentration of 3%, the electrolytic reaction can be completed in 57.5 minutes, thereby achieving the effect of shortening the electrolytic time course.

Figures 1a-1b: Schematic diagrams of X-ray diffraction (XRD) analysis of copper particles prepared by the copper particle preparation method of the present invention.

Figures 2a-2b: Scanning Electron Microscope (SEM) photos of copper particles prepared by the copper particle preparation method of the present invention.

Figures 3a to 3f: Particle size distribution diagrams of copper particles prepared by the copper particle preparation method of the present invention.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments of the present invention in detail with the accompanying drawings as follows: The first embodiment of the present invention The method for preparing copper particles is that by electrolyzing a copper-containing electrolyte at a predetermined current density, several copper particles are precipitated on the surface of a cathode electrode and deposited in the copper-containing electrolyte.

Specifically, the copper-containing electrolyte may be selected from the group consisting of a copper sulfate-containing solution and a copper chloride-containing solution, and the copper sulfate-containing solution contains copper ions at a concentration of 0.037 to 3% w / v. The copper chloride-containing solution contains copper ions at a concentration of 0.037 to 1% w / v. For example, the copper sulfate-containing solution with a copper ion concentration of 3% w / v or a copper ion concentration of 1% w / v can be selected. The copper chloride-containing solution is used as the copper-containing electrolyte, whereby the copper particle preparation method of the present invention can prepare the copper particles with a small particle diameter. In addition, the copper sulfate-containing solution having a copper ion concentration of 3% w / v and the copper chloride-containing solution having a copper ion concentration of 10% w / v are preferably mixed as the copper-containing electrolyte, and the copper ion concentration is The volume ratio of the copper chloride-containing solution to the copper-containing electrolyte at 10% w / v is 2 to 10%, whereby the copper particles having a particle size of less than 2 μm can be further prepared. In addition, the source of the copper sulfate-containing solution and the copper chloride-containing solution is not limited, and can be obtained by mixing commercially available pharmaceutical-grade copper sulfate powder or copper chloride powder with water, or by using The copper waste liquid is obtained by dilution (for example, industrial electroplating waste liquid and industrial etching waste liquid are obtained by dilution).

Preferably, the worker can adjust the pH of the copper-containing electrolyte to less than 3 with a sulfuric acid aqueous solution, and more preferably adjust the pH of the copper-containing electrolyte to less than -0.8, thereby improving the subsequent electrolytic reaction. Time current efficiency, thereby shortening the electrolysis time to save the production cost of the copper particles.

An anode electrode and the cathode electrode are continuously extended into the copper-containing electrolyte. For example, the copper-containing electrolyte may be carried in an electrolytic cell, and the anode electrode and the cathode electrode may be extended into the copper-containing electrolyte. Below the surface, the setting of the anode electrode and the cathode electrode can be completed. The anode electrode can be selected as an insoluble anode, for example, an inert electrode formed of graphite, titanium, titanium-plated group metals, and the like, so that the anode electrode does not react with the copper-containing electrolyte, and can extend the Effect of anode electrode life. In addition, the cathode electrode may be a conductive electrode formed of a material such as titanium, graphite, platinum, or a titanium-plated group metal. In this embodiment, the anode electrode and the cathode electrode are both titanium-plated iridium oxide electrodes formed of titanium-plated iridium oxide material, which has higher stability in an acidic solution, so the anode electrode and the cathode can be improved. Stability and durability of the electrode.

After the setting of the anode electrode and the cathode electrode is completed, a current can be applied to the anode electrode and the cathode electrode, so that a current loop can be formed between the anode electrode and the cathode electrode through the copper-containing electrolyte. It is worth noting that the copper particles can be precipitated and deposited in the copper-containing electrolyte under the operation of a current density of 10 to 100 A / dm ² , so the precipitated copper particles will not Adhering to the surface of the cathode electrode can save the time of removing and replacing the cathode electrode. Therefore, compared with the conventional method for preparing copper particles, it can be greatly shortened when the same amount of copper particles are obtained. Time course, therefore, the method for preparing copper particles of the present invention has better production efficiency.

In the foregoing method for preparing copper particles, by appropriately blending the components of the copper-containing electrolyte and operating under a specific current density interval, the generated copper particles will not adhere to the cathode electrode after precipitating from the cathode electrode. Therefore, the plurality of copper particles can be prepared quickly and easily, which can shorten the production time and improve the production efficiency. In addition, the produced copper particles have the effect of smaller particle size and more uniform particle size.

In order to confirm that the copper particle preparation method of the present invention can indeed effectively and quickly prepare dendritic copper particles with an average particle size of less than 3 μm, the following tests were performed: First, the copper-containing electrolytic solution of 1500 m1 was prepared according to the composition distribution ratio shown in Table 1. In particular, it should be noted that groups (IV) to (VI) consist of a solution containing copper sulfate with a copper ion concentration of 3% w / v and a solution containing chloride with a copper ion concentration of 10% w / v. Copper solutions were mixed as the copper-containing electrolyte, and the volume ratios of the copper chloride-containing solution to the copper-containing electrolyte with a copper ion concentration of 10% w / v were 2%, 5%, and 10%, respectively. After the copper-containing electrolyte was prepared, the anode electrode and the cathode electrode (also titanium-plated iridium oxide electrode) were extended into the copper-containing electrolyte, and the copper-containing electrolyte was operated under a current density of 21 A / dm ² . The electrolyte is electrolyzed.

As shown in Table 1, under the above-mentioned method, each group can produce the copper particles. Among them, the reaction time of group (I) only needs 57.5 minutes, so that the copper particles can be completely produced. The yield (100% yield) shows that the copper particle preparation method of the present invention can efficiently and quickly prepare the several copper particles; the reaction time of group (III) is shortened from 57.5 minutes to 50 compared with group (I). It is shown that adding sulfuric acid to the copper-containing electrolyte to reduce the pH value of the copper-containing electrolyte actually improves the current efficiency in the copper-containing electrolyte and shortens the electrolytic reaction time. On the other hand, please refer to groups (IV) to (VI). As the amount of copper chloride increases, the copper ion content in the copper-containing electrolyte also increases. Therefore, to achieve the same yield of 100% In addition, the required reaction time also needs to be increased from 50 minutes to 70 minutes.

Please refer to Figs. 1a to 1b, which are schematic diagrams of X-ray diffraction (XRD) analysis of copper particles prepared by the copper particle preparation method of the present invention. Among them, Fig. 1a is the copper particles prepared in group (II), and Fig. 1b is the standard copper pure spectrum of JCPDS 89-2838. It can be seen from the comparison of Figs. The copper particles and pure copper have the same peak at the same diffraction angle (2θ), which shows that the copper particles prepared by the copper particle preparation method of the present invention are high-purity copper particles.

In addition, please refer to Figs. 2a to 2b, which are scanning electron microscope (SEM) photographs of copper particles prepared by the copper particle preparation method of the present invention. Among them, Fig. 2a is prepared by group (III). Copper particles produced; Figure 2b is copper particles prepared in group (VI). Figures 2a to 2b show that the copper particles produced by the copper particle preparation method of the present invention can be dendritic in appearance, compared with ordinary non-dendritic copper particles, the appearance can be increased. By adding the grafting ratio between the several copper particles, the effect of having a higher specific surface area for reaction can be achieved, and it is advantageous for industrial applications.

In addition, the copper particles obtained from the copper-containing electrolytes of different compositions shown in Table 1 were analyzed by a median diameter (D50) using a nanometer particle size analyzer, and the analysis results are shown in Table 2.

Groups (I) to (VI) show that the particle diameters of the copper particles prepared by the copper particle preparation method of the present invention are all less than 3 μm. Among them, groups (IV) to (VI) show that when the copper-containing electrolyte When 0.2 ~ 1% copper chloride is contained, the particle size of the copper particles obtained can be less than 2 μm, especially the copper particle size obtained from group (VI) is the smallest, and the position diameter (D50) is 1.136. μm, particle size distribution is 0.548 ~ 1.292μm. In addition, please refer to Figs. 3a to 3f. The particle size distribution diagrams of copper particles are prepared according to the above groups (I) to (VI). From the pictures 3a to 3f, it can be seen that the copper particles produced by each group are The diameter distribution is concentrated, so the copper particle preparation method of the present invention can indeed produce copper particles with uniform particle size.

In summary, in the method for preparing copper particles of the present invention, by appropriately formulating the components of the copper-containing electrolyte, the generated copper particles will not adhere to the cathode electrode after precipitation from the cathode electrode. The number of copper particles can be prepared quickly and easily, and the production time can be shortened. In addition, the production method of the copper particles of the present invention can make the produced copper particles have a smaller particle size and a more uniform particle size, which is the effect of this case.

Although the present invention has been disclosed using the above-mentioned preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention. The technical scope protected by the invention, so the scope of protection of the present invention shall be determined by the scope of the appended patent application.

Claims (7)

A method for preparing copper particles, comprising: providing a copper-containing electrolyte, the copper-containing electrolyte is selected from the group consisting of a copper sulfate-containing solution and a copper chloride-containing solution, and the copper sulfate-containing solution contains a concentration of 0.037 ~ 3% w / v copper ions, the copper chloride-containing solution contains copper ions at a concentration of 0.037 ~ 1% w / v; an anode electrode and a cathode electrode are protruded into the copper-containing electrolyte, the anode The electrode is an insoluble electrode; and a current is applied to the anode electrode and the cathode electrode, and the copper-containing electrolyte is electrolyzed under a current density operation of 10 to 100 A / dm ^{2 to} precipitate and deposit several copper particles on the electrode. Copper electrolyte. The method for preparing copper particles according to item 1 of the scope of patent application, wherein the copper sulfate-containing solution having a copper ion concentration of 3% w / v or the copper chloride-containing solution having a copper ion concentration of 1% w / v is selected. As this copper-containing electrolyte. The method for preparing copper particles according to item 1 of the scope of patent application, wherein the copper sulfate-containing solution having a copper ion concentration of 3% w / v and the copper chloride-containing solution having a copper ion concentration of 10% w / v The volume ratio of the copper chloride-containing solution to the copper-containing electrolytic solution as the copper-containing electrolytic solution with a copper ion concentration of 10% w / v is 2 to 10%. The method for preparing copper particles according to any one of claims 1 to 3, wherein the pH of the copper-containing electrolyte is adjusted to less than 3 with a sulfuric acid aqueous solution before the copper-containing electrolyte is electrolyzed. The method for preparing copper particles according to any one of claims 1 to 3, wherein a titanium-plated iridium oxide electrode is selected as the anode electrode. The method for preparing copper particles according to any one of claims 1 to 3, wherein a titanium-plated iridium oxide electrode is selected as the cathode electrode. The method for preparing copper particles according to any one of claims 1 to 3, wherein, under the current density operation of 21 A / dm ² , several copper particles are precipitated and deposited in the copper-containing electrolyte .