JP6011992B2 - Method for producing electrolytic copper powder - Google Patents

Description

The present invention, the second oxidation with and the electrolytic copper powder powder electrolytic copper powder suitable for the manufacture of cupric oxide powder for supplying copper ions to the copper sulfate aqueous solution used in the plating solution of copper electroplating The present invention relates to a method for producing copper fine powder, and further relates to a method for supplying copper ions in an aqueous copper sulfate solution.

Electrolytic copper powder powder is conductive Bae mixed with powder metallurgical raw materials and resin - is used as a strike. Although copper oxide powder and heat-treating the copper powder as shown in Non-Patent Document 1 is known to be obtained, the production method by heat-treating the powder electrolytic copper powder obtained cupric oxide powder is generally Wet method and dry method are widely used. In addition, the use of the obtained cupric oxide powder is known as a copper source for replenishing pigments, paints, catalysts, ceramic materials, ceramic colorants and copper sulfate aqueous solutions for copper plating solutions.
Electrolytic copper powder weekend, an anode and a cathode immersed in sulfuric acid aqueous solution (electrolyte solution) containing copper ions are produced by precipitating powdery copper cathode by performing electrolysis. Copper processed into a plate shape is used for the anode, and stainless steel or titanium is used for the cathode. The anode also serves to supply copper ions by being dissolved in an aqueous sulfuric acid solution containing copper ions during electrolysis. In this series of electrolytic copper powder at the end of the manufacturing process, comparing the current efficiency and current efficiency of deposition of electrolytic copper powder at the end of the cathode of the dissolution of copper anodes, higher in current efficiency of the dissolution of the copper at the anode. Therefore, the concentration of copper ions in sulfuric acid aqueous solution is gradually increased, since the result affects the quality of the end electrolytic copper powder precipitated, requires means for maintaining the copper ion sulfuric acid aqueous solution approximately constant become. Therefore, Patent Document 1 is provided with an electrolytic solution (sulfuric acid aqueous solution) provided with a normal bath using copper as an anode and a decopper electrolytic bath provided with an insoluble anode in which the surface of a valve metal such as titanium is covered with a noble metal oxide. prevents an increase in copper ion concentration), technology of obtaining a high purity electrolytic copper powder late is disclosed.
However, since the solubility of copper in using the anode an insoluble anode is not generated by electrolysis of water highly active oxygen is generated in the nascent state, such as passivation of electrolytic copper powder at the end of production equipment damage There is a risk of giving. In order to prevent such damage to equipment, measures are taken to dispose an insoluble anode in an anode bag (also referred to as an anode bag) formed of an ion exchange membrane. When an insoluble anode is used, there is a problem that the equipment and its operating cost increase due to the installation of a copper removal electrolyzer and the management of the anode back.

  As a method for producing cupric oxide powder, a wet method and a dry method are known. The cupric oxide powder obtained by any manufacturing method has a problem in quality.

  As described in Patent Document 2, for example, the wet method is a method in which sodium hydroxide is reacted with an aqueous solution of cupric chloride or copper sulfate to form copper hydroxide and then heated.

  More specifically, the etching waste solution of the printed circuit board containing cupric chloride is neutralized with caustic alkali, and the neutralized copper solution and caustic aqueous solution are simultaneously dropped into an aqueous solution maintained at a temperature of 40 to 50 ° C. Mixing to form a copper hydrate while maintaining the pH of the mixed aqueous solution in a weakly acidic to weakly alkaline range. Next, Patent Document 1 proposes a method of preparing cupric oxide by adjusting the pH to 12 to 13 and maintaining the temperature at 70 to 80 ° C. for 30 minutes, followed by washing with water and solid-liquid separation.

  However, since sodium chloride (NaCl) is produced as a by-product as an impurity, there is a problem that a water washing step is necessary for removing impurities, and that it is difficult to completely remove even after washing with water. Yes.

  In Patent Document 3, a copper sulfate aqueous solution and a sodium hydroxide aqueous solution are reacted at a temperature of 30 ° C. or lower to produce cupric hydroxide, and then heated and aged at a temperature of 60 to 80 ° C. A manufacturing method for forming cupric oxide is disclosed.

  Many cupric oxide powders manufactured by the wet method shown in Patent Documents 2 and 3 have excellent solubility in a copper plating solution.

However, the cupric oxide powder obtained by this method has a problem that the residual concentration of S in Na and SO ₄ bodies is high as an impurity. When a copper sulfate aqueous solution of a plating solution is used, the cupric oxide powder is caused by the impurity. Problems such as plating defects were likely to occur.

On the other hand, as described in Non-Patent Document 1, the dry method is a method in which copper nitrate, copper sulfate, copper carbonate, copper hydroxide, etc. are thermally decomposed at about 600 ° C. in the air, compared with the wet method. The productivity is high, and when metallic copper is used as a raw material, there is an advantage that high-purity cupric oxide can be obtained.
However, since the pyrolysis temperature is high in the dry method, the obtained cupric oxide powder has a problem that the dissolution rate in the plating solution becomes extremely slow due to the influence of sintering.
Wet method and dry method described above, there is a quality issue, the electrolytic copper powder powder as a cupric oxide fine powder of the raw material is cost issue.

Japanese Patent Laying-Open No. 2005-163096 JP-A-5-31825 Japanese Patent Laid-Open No. 3-80116

4th edition experimental chemistry course inorganic compounds

It is an object of the present invention, the above-mentioned problems, i.e., equipment cost is inexpensive, and the purity is to provide a high oxidative second method of manufacturing an electrolytic copper powder powder for copper powder, electrolytic high purity at low cost in the dissolution rate at a high purity to provide a high cupric oxide fine powder production method of using copper powder powder.

Therefore, in order to solve the above-mentioned problems, the present inventors have continued intensive research. As a result, even in a method for producing electrolytic copper powder by electrolysis of a copper ion-containing sulfuric acid aqueous solution using metal copper as an anode, an anode current density of 10 A / dm. and be ^{2 ~40A} / dm ^2, a phenomenon that inexpensive high electrolytic copper powder powder purity that the temperature of the sulfuric acid aqueous solution of copper ions contained in the a 45 ° C. to 65 ° C. during electrolysis is obtained, further purity and dissolution rate is high cupric oxide powder electrolytic copper powder powder to pulverizing and second heat treatment and the primary heat treatment was obtained and found a phenomenon that is obtained.

That is, according to the first aspect of the present invention, in the method for producing an electrolytic copper powder for cupric oxide powder raw material by electrolysis of a copper ion-containing sulfuric acid aqueous solution using metal copper as an anode, an insoluble anode is not used as the anode. The disproportionation reaction is performed by setting the anode current density to 10 to 40 A / dm ² to generate monovalent copper ions, and the temperature of the aqueous copper solution during electrolysis is 45 ° C. to 65 ° C. Features.

The second invention of the present invention is characterized in that the anode is made of electrolytic copper or oxygen-free copper, and a liquid solution of an acidic sulfuric acid solution containing copper ions is sprayed on the surfaces of the anode and the cathode. an electrolytic copper powder method according to the present invention.

A third aspect of the present invention is the manufacturing method of the cupric oxide fine powder of heat-treating the electrolytic copper powder,
Oxidation of the electrolytic copper powder powder and a the use of electrolytic copper powder powder electrolytic copper powder powder obtained by the method according to the first or second invention, the heat treatment, and heat-treated primary in an oxygen-containing atmosphere A step of obtaining a cupric coarse powder, a step of pulverizing the cupric oxide coarse powder to obtain a primary heat treated cupric oxide fine powder, and the primary heat treated cupric oxide fine powder under an oxygen-containing atmosphere. And a secondary heat treatment step.

The fourth invention of the present invention is a method of supplying copper ions to a copper sulfate aqueous solution in which the cupric oxide fine powder is dissolved to adjust the copper ion concentration of the copper sulfate aqueous solution, wherein the cupric oxide fine powder comprises: The cupric oxide fine powder obtained by the method for producing cupric oxide fine powder according to the third aspect of the invention, and the cupric oxide fine powder , CuSO ₄ .5H ₂ O, 50 g / liter to 130 g / liter, H ₂ SO ₄ is dissolved in an aqueous solution containing 150 to 240 g / liter and chlorine ions of 30 to 70 mg / liter.

According to the method of manufacturing an electrolytic copper powder powder according to the present invention can produce a large amount of high copper Powder purity by simple equipment. The obtained electrolytic copper Powder is and readily soluble in an aqueous copper sulfate solution with high purity by the production method of the cupric fine powder oxide of the present invention is useful as a source of copper ions the copper electroplating solution.

Is an SEM image of the electrolytic copper Powder a.

[Method for powder electrolytic copper powder]
Method of manufacturing an electrolytic copper powder powder according to the present invention, when the electrolysis of sulfuric acid aqueous solution containing copper ions and the copper metal as an anode, the method comprising: an anode current density of ^{10A / dm 2 ~40A / dm 2} , electrolytic The temperature of the copper aqueous solution at the time is 45 ° C to 65 ° C.
The method for producing electrolytic copper powder powder according to the present invention will be described.
Method for producing a powder electrolytic copper powder, the anode and the cathode immersed in a sulfuric acid acidic aqueous solution containing copper ions, to recover electrolytic copper Powder precipitated by electrolysis.
As the anode used in the present invention, a plate shape, chip shape, or ball shape selected from electrolytic copper or oxygen-free copper can be used. When using a chip-shaped or ball-shaped anode, a chip-shaped or ball-shaped anode may be filled in a titanium basket that does not dissolve in an aqueous sulfuric acid solution containing copper ions. The chip-shaped and ball-shaped anodes are in contact with each other to conduct electricity. Chip-like or ball-shaped anode surface area wider than the plate-shaped anode, the dissolution of copper is accelerated, depending on the deposition conditions of the fine electrolytic copper powder, plate-like, chip-like, appropriately selected ball-shaped That's fine. However, phosphorous copper used in copper sulfate plating must not be used for these anodes. This is because it becomes difficult to disproportionate when phosphorous copper is used.

The cathode used in the present invention is a stainless plate or a titanium plate. The use of stainless steel plate or a titanium plate cathode, deposited electrolytic copper powder at the end of the peeling becomes easy.
The composition of the sulfuric acid aqueous solution containing copper ions is 15 g / liter to 120 g / liter for copper sulfate and 150 g / liter to 220 g / liter for sulfuric acid.
In the method for manufacturing the electrolytic copper powder powder according to the present invention, the electrolysis temperature at 45 ° C. to 65 ° C., a current density of the anode and the cathode are ^{10A / dm 2 ~40A / dm 2} .
Comparing the current efficiency and current efficiency of deposition of electrolytic copper powder at the end of the cathode of the dissolution of copper anodes, higher in current efficiency of the dissolution of the copper at the anode. Therefore, since the concentration of copper ions in the sulfuric acid aqueous solution containing copper ions increases, it is necessary to take measures such as providing a copper removal tank equipped with an insoluble anode. For example, in the technology disclosed in Patent Document 1, the current density is less than 10 A / dm ² and measures such as an insoluble anode are taken.
In a sulfuric acid aqueous solution containing copper ions in which current is flowing due to electrolysis (electrolysis) or the like, monovalent copper ions and divalent copper ions are in an equilibrium state. In the method of manufacturing the electrolytic copper powder powder according to the present invention, a high current density anode, i.e., by a current density ^{10A / dm 2 ~40A / dm 2} , the monovalent copper ions on the surface of the copper of the anode actively generate, thereby depositing copper powder by disproportionation reaction shown in equation (1).
2Cu ⁺ → Cu + Cu ²⁺ (1)
Therefore, a part of the copper ions generated by the dissolution of the anode is consumed by the disproportionation reaction, and the supply of copper ions does not become excessive. The resulting electrolytic copper powder at the end of the production method of the present invention measures such as insoluble anodes is not necessary. Since an insoluble anode is not used, an anode back formed of an ion exchange membrane is unnecessary.

Moreover, copper powder and electrolytic copper powder powder deposited on the cathode to generate in the disproportionation reaction has high purity copper, metals other than copper are not included. Moreover, since a copper removal tank is unnecessary, the equipment cost is low and the productivity is excellent. In addition, the copper powder produced | generated by disproportionation reaction may be partially oxidized. That is, cuprous oxide (Cu ₂ O) may be contained in the copper powder due to monovalent copper ions, but the obtained copper powder is processed into cupric oxide powder by heat treatment, so there is no problem. .
Previous electrolytic copper powder powder obtained in the description (hereinafter, the combined copper powder disproportionation copper powder and the anode of cathode copper powder) particle size of is 100μm or less.
The liquid is not particularly limited as long as it can maintain a fluid state. For example, an electrolytic solution is injected onto the surfaces of the anode and the cathode, and a copper sulfate acid aqueous solution containing copper ions is directly sprayed at a flow rate of 10 liters / minute or more with a liquid feed pump. It is preferable to float the powder. And the copper powder which floated in the sulfuric acid acidic aqueous solution containing copper ion is collect | recovered with a filter, centrifugal filtration, etc., and obtains copper powder through water washing and drying. Furthermore, the copper powder may be partially oxidized. Even if cuprous oxide (Cu ₂ O) is contained in the copper powder due to monovalent copper ions, the obtained copper powder is processed into cupric oxide powder by heat treatment, so there is no problem.

[Manufacturing method of cupric oxide fine powder]
(1) forming cupric oxide coarse powder cupric oxide coarse powder be formed by performing the heat treatment was 350 ° C. to 800 ° C. The maximum temperature of the electrolytic copper powder powder as a raw material in an oxygen-containing atmosphere Can do.

  If the maximum temperature in the heat treatment is less than 350 ° C., it takes a long time for the oxidation or a heterogeneous phase is mixed.

  In particular, the problem is the heterogeneous phase. Of the heterogeneous phases, cuprous oxide does not dissolve in the plating solution that is an aqueous copper sulfate solution. For this reason, the presence of a different phase is considered to adversely affect the solubility of the plating solution and the properties of the plating solution.

On the other hand, the upper limit of the maximum temperature is preferably 800 ° C. from the viewpoint of pulverization in a medium stirring mill or an airflow mill. When the maximum temperature of the heat treatment exceeds 800 ° C., the cupric oxide coarse powder is sintered and pulverized. It becomes difficult to do. Although the atmosphere can be selected as appropriate, heat treatment may be performed in the air.
(2) Grinding treatment and primary heat treatment cupric oxide powder The primary heat treatment cupric oxide fine powder is obtained by grinding a cupric oxide coarse powder.

  The powder characteristics of the bulk density, tap density, specific surface area, and average particle size in the pulverization process determine the powder characteristics of the secondary heat-treated cupric oxide fine powder. The secondary heat treatment described later does not sinter the primary heat-treated cupric oxide fine powder.

  It is desirable to use a medium stirring mill or an airflow mill for pulverizing the cupric oxide coarse powder. When this medium stirring mill is used, it is possible to reduce the possibility that particles having an average particle diameter of more than 1100 nm determined by the following formula (2) can be formed.

  The media agitation mill gives kinetic energy to the slurry containing beads, such as powdered grinding media, cupric oxide coarse powder, and solvent by stirring. It is a device that obtains fine powder by the shear stress of the powder.

  The stirring mechanism of the medium stirring mill is not particularly limited as long as the shear stress of the beads is efficiently transmitted to the cupric oxide coarse powder.

  The bead diameter that is the powder grinding medium is generally selected according to the final particle diameter of the desired cupric oxide fine powder, but is preferably 1 mm or less in diameter. If it is 1 mm or less in diameter, the efficiency which grinds particles finely will become high.

  Furthermore, the smaller the bead diameter, the faster the pulverization speed and the smaller the particle diameter of the pulverized copper oxide powder. In particular, beads having a diameter of 0.3 mm or less are particularly preferable for pulverization to a particle diameter having high solubility in the plating solution.

The material of the beads is not particularly limited, and examples thereof include glass beads having a low specific gravity, ZrO ₂ beads having a high specific gravity, and YSZ beads. Beads having a large specific gravity are particularly preferable because of high powder crushing efficiency and low wear.

  The medium stirring mill is not particularly limited, and examples thereof include a bead mill, a ball mill, a sand mill, a paint shaker, and an ultrasonic homogenizer.

  On the other hand, the airflow mill is a device that obtains fine powder by causing the cupric oxide coarse powder to collide with each other in a high-speed jet stream.

  The pulverization conditions are not particularly limited regardless of whether the wet medium mill or the airflow mill is used, so that the obtained cupric oxide fine powder has a desired specific surface area and average particle diameter. What is necessary is just to select suitably.

  The solvent is not particularly limited, and examples thereof include water, ethanol, propanol, butanol, isopropyl alcohol, isobutyl alcohol, diacetone alcohol and other ethers, methyl ether, ethyl ether, propyl ether and other ethers, and esters. Alternatively, various organic solvents such as acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, and ketones such as isobutyl ketone can be used.

  Furthermore, depending on the intended use of the cupric oxide fine powder, a known antifoaming agent or dispersant, a compound that coats the surface of the cupric oxide fine powder, or the like may be added to the slurry as appropriate.

(3) Secondary heat treatment The primary heat-treated cupric oxide fine powder obtained through the above steps is heat-treated in an oxygen-containing atmosphere to form a secondary heat-treated cupric oxide fine powder.

  The heat treatment temperature is desirably 200 ° C. to 800 ° C., and the heat treatment time is desirably 0.5 hours to 3 hours, but both are appropriately selected so as to finally form a complete CuO form.

The solubility of the obtained cupric oxide fine powder in the plating solution by the secondary heat treatment in the oxygen-containing atmosphere is further increased from the state of partial oxygen deficiency (CuO _1-x ). This is presumed to be in the state of CuO.

If this secondary heat treatment temperature is less than 200 ° C., it is estimated that a partial oxygen deficiency state (CuO _1-X ) may remain and is not in a complete CuO state. It seems that the defect (CuO _1-X ) remained in a deficient state and was not detected by X-ray diffraction.

  It should be noted that this secondary heat treatment does not sinter the primary heat treated cupric oxide fine powder. Therefore, the above heat treatment temperature and heat treatment time are desirable.

  Furthermore, the manufacturing method of the cupric oxide fine powder according to the present invention performs the secondary heat treatment of the finely powdered primary heat treated cupric oxide fine powder obtained by pulverizing the cupric oxide coarse powder. Cheap. The dissolution time in the copper sulfate aqueous solution is shortened by performing the secondary heat treatment.

Therefore, the cupric oxide fine powder of the present invention is more desirable as a replenishing copper source for copper plating. Specifically, the dissolution time of 7 g of the cupric oxide fine powder obtained by the production method of the present invention is 90 g / liter for CuSO ₄ .5H ₂ O, 220 g / liter for H ₂ SO ₄ , and chlorine ion. It contains 60 mg / liter and has a solubility that dissolves in 2 minutes or less when added to a stirred 1 liter aqueous copper sulfate solution.

As described above, cupric oxide fine powder obtained has a effect of secondary heat treatment, a specific surface area of ^{1m 2} / ^g~50m 2 / g, and an average particle diameter of 20nm~1100nm next, an aqueous solution of copper sulfate Solubility in (plating solution) increases. In addition, the said average particle diameter is the value calculated | required from the following (2) formula.
d = 6 / (ρ · S) (2)
d: particle diameter, ρ: true density, S: specific surface area

[Copper ion supply method for copper sulfate aqueous solution (plating solution)]
A copper plating solution (copper sulfate aqueous solution) used for electrolytic plating of copper contains copper sulfate, sulfuric acid and chlorine ions, and a pH lower than 1 is often used. A known additive is added to the copper plating solution to improve the quality of the copper plating.

  On the other hand, when copper is electroplated, copper in the plating solution is deposited, and the concentration of copper in the plating solution is lowered. Therefore, in order to prevent a decrease in the copper concentration of the plating solution, a method of performing copper electroplating while dissolving the anode using copper as the anode, and an insoluble anode made of titanium or the like covered with a conductive oxide ceramic on the anode And an insoluble anode having a mechanism for supplying copper to the plating solution.

  In the case of the method using this insoluble anode, how to supplement copper to the plating solution becomes a problem.

To supply copper to the plating solution, the copper source such as copper or a compound containing copper dissolves rapidly in the plating solution, and the balance of SO ₄ ²⁺ ions of the plating solution is lost due to the dissolution of the copper source. Further, it is required that the additive contained in the plating solution does not decompose.

In response to such demands, cupric oxide fine powder has the advantage that the balance of SO ₄ ²⁺ ions and the like of the plating solution is not lost, and the decomposition of various additives is small.

  Furthermore, it is necessary to supply the copper to the plating solution promptly whenever the copper in the plating solution decreases.

Specifically, cupric oxide powder is added to 1 liter of an aqueous solution approximating a plating solution containing 90 g / liter of stirred CuSO ₄ .5H ₂ O, 220 g / liter of H ₂ SO ₄ and 60 mg / liter of chlorine ions. The shorter the dissolution time when 7 g is added, the more desirable.

  The cupric oxide fine powder according to the present invention dissolves within 2 minutes when introduced into 1 liter of an aqueous solution similar to the above plating solution.

  Moreover, the cupric oxide fine powder thrown into the plating solution should not produce a dissolution residue.

  In particular, cuprous oxide should be prevented from being formed because it is not dissolved in the plating solution and becomes a residue. In the manufacturing method of cupric oxide fine powder of the present invention, cuprous oxide which becomes a different phase by heat treatment at the time of manufacturing cupric oxide coarse powder is hard to occur.

  Further, under the heat treatment conditions, a cupric oxide crude powder that can be made fine by a medium agitating mill or an airflow mill is obtained. A fine copper powder will be obtained. Therefore, it is possible to adjust the plating solution, that is, supply copper ions to the aqueous copper sulfate solution.

  In order to carry out the method of supplying copper ions to the aqueous copper sulfate solution of the present invention in an electrolytic plating apparatus, a cupric oxide dissolution tank that dissolves cupric oxide fine powder separately from the plating tank for plating of the electrolytic plating apparatus And an aqueous solution (plating solution) may be circulated between the plating tank and the cupric oxide dissolution tank.

  This cupric oxide dissolution tank returns an aqueous solution formed by dissolving cupric oxide fine powder in the aqueous solution supplied from the plating tank to the plating tank. It is preferable to attach a stirring mechanism such as a propeller to the cupric oxide dissolution tank to be used. Moreover, you may provide a well-known various filter between a plating tank and a cupric oxide dissolution tank for removal of a dust, a foreign material, etc.

  The copper sulfate aqueous solution used in the method for supplying copper ions to the copper sulfate aqueous solution of the present invention may be an aqueous solution in which copper sulfate is dissolved in water, or the cupric oxide fine powder according to the present invention is dissolved in sulfuric acid. An aqueous solution may be used.

  Examples of the present invention will be specifically described below together with comparative examples.

[Example 1]
As the composition of the sulfuric acid aqueous solution containing copper ions, electrolysis was performed for 60 minutes or more under the conditions of copper sulfate 75 g / liter, sulfuric acid 220 g / liter, electrolysis temperature 45 ° C., anode and cathode current density 15 A / dm ² . A copper plate was used for the anode and a stainless plate was used for the cathode. Stripping the copper powder deposited on the cathode, the copper powder in sulfuric acid aqueous solution containing copper ions was collected and mixed together, washed with water, followed by filtration, thereby preparing an electrolytic copper Powder a. Figure 1 shows an SEM image of the resulting electrolytic copper Powder a. As a result of the powder X-ray analysis of the obtained copper Powder a, Cu and weak Cu 2 _O phase of the main phase were observed.

Next, to obtain a copper oxide crude powder a by heat treating for 3 hours primary at a temperature of the atmosphere 500 ° C. The electrolytic copper Powder a in a box furnace. It obtained the copper oxide coarse powder a20 wt%, were weighed so as to be 80% by weight of water, 0.3MmfaiZrO ₂ bi -'s after 12 hours milling in a paint shaker containing the (E Retoreseramu 0.3mmφZrHIP beads) The dispersion liquid from which the beads were separated was dried at 105 ° C., and further subjected to secondary heat treatment at 500 ° C. for 3 hours in an air atmosphere in a box furnace to obtain copper oxide fine powder a. Moreover, it was a CuO single phase as a result of the powder X-ray analysis of the copper oxide fine powder a.

Next, CuSO ₄ · 5H ₂ O 68 g / liter, H ₂ SO ₄ 228 g / liter, and Cl ion 60 mg / liter were prepared as an aqueous copper sulfate solution (plating solution). While stirring at −, 7 g of cupric oxide fine powder a was added and dissolved in 43 seconds.

[Example 2]
Except for changing the temperature of the electrolyte to 60 ° C. was obtained electrolytic copper Powder b according to the second embodiment in the same manner as in Example 1. The anode did not passivate. Then, when obtained by the electrolytic copper Powder b to cupric oxide powder b under the same conditions as in Example 1 was evaluated solubility in aqueous copper sulfate solution, and dissolved in 40 seconds.

[Example 3]
60 ° C. The temperature of the electrolyte, except for changing the anodic current density 30A / dm ² was obtained electrolytic copper Powder c according to the third embodiment in the same manner as in Example 1. The anode did not passivate. Then, when obtained by the electrolytic copper Powder c in the cupric fine powder c oxidation under the same conditions as in Example 1 was evaluated solubility in aqueous copper sulfate solution, and dissolved in 41 seconds.

[Example 4]
60 ° C. The temperature of the electrolyte, except for changing the anodic current density 40A / dm ² was obtained electrolytic copper Powder d according to Example 4 in the same manner as in Example 1. The anode did not passivate. Then, when obtained by the electrolytic copper Powder d to cupric oxide powder d under the same conditions as in Example 1 was evaluated solubility in aqueous copper sulfate solution, and dissolved in 43 seconds.

[Example 5]
The same as in Example 1 except that the electrolytic solution temperature was changed to 45 ° C., the anode current density was changed to 20 A / dm ² , and electrolysis was performed by injecting a liquid flow to the anode and cathode surfaces by a liquid feed pump at 10 liters / minute. the electrolytic copper powder e according to the fifth embodiment in the yield. The anode did not passivate. Then, when obtained by the electrolytic copper Powder e to cupric oxide powder e under the same conditions as in Example 1 was evaluated solubility in aqueous copper sulfate solution, and dissolved in 40 seconds.

[Example 6]
In Example 5, the electrolytic solution temperature was changed to 60 ° C., the anode current density was changed to 40 A / dm ² , and the electrolysis was performed by injecting the liquid flow to the anode and cathode surfaces by a liquid feeding pump at 10 liters / minute. thereby preparing an electrolytic copper powder f according to the sixth embodiment in the same manner as in example 5. The anode did not passivate. Then, it was evaluated solubility in aqueous solution of copper sulfate in the resulting cupric oxide fine powder f electrolytic copper Powder f under the same conditions as in Example 1, was dissolved in 43 seconds.

[Comparative Example 1]
Electrolysis was performed in the same manner as in Example 1 except that the electrolyte temperature was changed to 30 ° C., but the anode was passivated in 15 minutes.

[Comparative Example 2]
Electrolysis was carried out in the same manner as in Example 2 except that the electrolyte temperature was changed to 30 ° C., but the anode was deactivated in 4 minutes.

[Comparative Example 3]
The electrolysis was performed in the same manner as in Example 3 except that the electrolyte temperature was changed to 30 ° C., but the anode was deactivated in 2 minutes.

Claims (2)

In the method for producing electrolytic copper powder by electrolysis of an aqueous sulfuric acid solution containing metallic copper as an anode and copper ions,
Do not use an insoluble anode for the anode,
A disproportionation reaction is performed by setting the anode current density to 10 A / dm ^{2 to} 40 A / dm ² to generate monovalent copper ions;
The temperature of the aqueous copper solution during electrolysis is 45 ° C to 65 ° C,
The manufacturing method of the electrolytic copper powder for cupric oxide powder raw materials characterized by these. 2. The method for producing electrolytic copper powder according to claim 1, wherein the anode is made of electrolytic copper or oxygen-free copper, and a liquid flow of a sulfuric acid aqueous solution containing copper ions is sprayed on the surfaces of the anode and the cathode. .