JP4551628B2 - Method for producing nitrogen-free nickel powder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Relates to a manufacturing method of the present invention is a nitrogen-free nickel powder, and more particularly, a nitrogen-free, the average particle size in the monodisperse 0.05 to 1 [mu] m, high crystallinity, a method for producing a high purity nickel powder.
[0002]
[Prior art]
When nickel powder is produced by the polyol method, it is known that nickel powder having high crystallinity, high purity, and uniform particle diameter can be obtained (for example, see Patent Documents 1 and 2). However, in order to control the particle size, it is indispensable to add a dispersant for suppressing aggregation of the catalyst and the catalyst. In general, a noble metal salt, a noble metal oxide, or the like is used as a catalyst, and a nitrogen-containing organic compound such as polyvinyl pyrrolidone, polyethyleneimine, or polyacrylamide is used as a dispersant.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 4-24402 [Patent Document 2]
Japanese Patent No. 3005683 [0004]
[Problems to be solved by the invention]
However, since the dispersant as described above is firmly bonded to the surface of the nickel particles to be generated, it remains on the surface of the particles even after washing, and therefore it is very difficult to remove the dispersant.
An object of the present invention is to provide a method for producing a nickel-free, monodispersed, high crystal, high purity nickel powder.
[0005]
[Means for Solving the Problems]
As a result of intensive investigations to achieve the above object, the present inventors have found that by using a specific organic acid as a dispersant, a nickel-free, monodispersed, high crystal, high purity nickel powder can be obtained. The headline and the present invention were completed.
[0006]
That is, the method for producing a nitrogen-free nickel powder having an average particle diameter of 0.05 to 1 μm according to the present invention comprises a dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid , and a noble metal compound catalyst. A powder selected from the group consisting of nickel salt powder and nickel hydroxide powder is suspended in the contained polyol, and the powder is heated to a temperature sufficient to reduce the powder to nickel powder. .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The dispersant used in the production method of the present invention is a dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid.
[0008]
As a noble metal compound catalyst used in the production method of the present invention, palladium compounds such as palladium chloride, palladium nitrate, palladium acetate, ammonium chloride palladium and palladium oxide, silver nitrate, silver lactate, silver oxide, silver sulfate, silver cyclohexane acid, silver acetate and the like Silver compounds, platinum compounds such as chloroplatinic acid, potassium chloroplatinate, and sodium chloroplatinate, and gold compounds such as chloroauric acid and sodium chloroaurate. From the viewpoint of cost and nickel powder purity Palladium nitrate, palladium acetate, palladium oxide, silver nitrate, silver acetate and silver oxide are preferred.
[0009]
Examples of the polyol used in the production method of the present invention include various polyols described in Japanese Patent Publication No. 4-24402. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1 , 2-propanediol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, and mixtures thereof. In the production method of the present invention, a polyol which is liquid at the reaction temperature is used.
[0010]
Examples of the nickel salt and nickel hydroxide used in the production method of the present invention include nickel sulfate, nickel nitrate, nickel chloride, nickel bromide, nickel hydroxide and the like.
[0011]
In the production method of the present invention, in consideration of the reaction rate, a suspension in which a powder selected from the group consisting of nickel salt powder and nickel hydroxide powder is suspended is reduced to nickel powder. It needs to be heated to a temperature sufficient to do so. The heating temperature is preferably 85 ° C. or higher, and more preferably 100 ° C. or higher. The upper limit of the heating temperature is limited by the lowest temperature among the boiling point or decomposition temperature of the dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid used , and the boiling point of the polyol.
[0013]
In the production method of the present invention, the content of the dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid is 0.01% by mass or more of the amount of polyol, preferably 0 of the amount of polyol. It is suitable that it is 0.05-5 mass%. When the content of the dispersing agent selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid is less than 0.01% by mass of the amount of polyol, the effect intended in the present invention is insufficient. Tend to be.
[0014]
In the production method of the present invention, maleic anhydride, but use a dispersing agent selected from the group consisting of fumaric acid and n- hexanoic acid, has preferably be used maleic anhydride or fumaric acid.
[0015]
In the production method of the present invention, by carrying out under the above-mentioned various conditions, the nitrogen content of the nickel powder is 10 ppm or less and is nitrogen-free, with a monodisperse, high crystal, and high average particle size of 0.05 to 1 μm. A pure nickel powder is obtained.
[0016]
【Example】
The present invention will be specifically described below based on examples and comparative examples.
Example 1
400 mL of ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.91 g of maleic anhydride (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersing agent are added to a 500 mL separable flask, and stirred at a rotation speed of 350 rpm for anhydrous maleic anhydride. The acid was dissolved.
[0017]
To the above solution, 38.29 g of nickel hydroxide (manufactured by OM Group) and 0.1 mL of palladium nitrate aqueous solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) prepared to 0.84 g / 1000 mL were added and heated to 190 ° C. . As the temperature increased, the liquid color in the container changed from green to black. By-product water, organic matter, and the like were distilled off through a distillation line. After reaching 190 ° C., sampling was performed every hour, and the progress of the reaction was confirmed by XRD. It was confirmed that nickel powder was produced by complete reduction in 5 hours.
[0018]
After completion of the reaction, the temperature was lowered to room temperature, and the solid and liquid were separated by suction filtration. The obtained solid (cake) was put into a 500 mL beaker, 300 mL of pure water was added and the mixture was vigorously stirred, and then the solid and liquid were separated by a suction filtration method. This operation was performed twice.
Next, the cake was put into a 500 mL beaker, 300 mL of methanol was added and vigorously stirred, and then the cake was collected by suction filtration and dried at 80 ° C. for 5 hours to obtain nickel powder.
[0019]
The average primary particle size (average particle size of primary particles) of the obtained nickel powder by SEM observation is 0.3 μm, and the particle size distribution is measured by a laser diffraction scattering type particle size distribution measuring device X-100 (manufactured by Microtrac). ) results measured _{at, D 10} is 0.29 _{.mu.m, D 50} is 0.41 _{.mu.m, D 90} is 0.64 .mu.m, and _{D max} was 1.38 .mu.m.
[0020]
Nickel powder was processed by FIB, and the cross section was taken on an electron micrograph. The electron micrograph is shown in FIG. As is clear from the observation in FIG. 1, there was almost no grain boundary and the crystal was highly crystalline.
[0021]
XRD measurement was performed, and the crystallite size was determined by the Scherrer method. As a result, the 111th surface was 323mm, the 200th surface was 193mm, and the 220th surface was 206mm.
Further, as a result of purity analysis, C was 0.15% by mass, O was 0.50% by mass, and N was 0.0009% by mass (9 ppm).
[0022]
Example 2
Nickel powder was obtained in the same manner as in Example 1 except that fumaric acid was used instead of maleic anhydride.
The average primary particle size (average particle size of primary particles) of the obtained nickel powder by SEM observation is 0.3 μm, and the particle size distribution is measured with a laser diffraction scattering type particle size distribution measuring device X100 (manufactured by Microtrack). the measurement _{results, D 10} is 0.30 _{.mu.m, D 50} is 0.42 _{.mu.m, D 90} is 0.65 .mu.m, and _{D max} was 1.38 .mu.m.
[0023]
The nickel powder was processed by FIB, and the cross section was taken and observed with an electron micrograph. There was almost no grain boundary, and it was highly crystalline as in Example 1.
XRD measurement was performed, and the crystallite size was determined by the Scherrer method. As a result, the 111th surface was 320 mm, the 200th surface was 188 mm, and the 220th surface was 202 mm.
As a result of the purity analysis, C was 0.17% by mass, O was 0.52% by mass, and N was 0.001% by mass (10 ppm).
[0024]
Example 3
Nickel powder was obtained in the same manner as in Example 1 except that n-hexanoic acid was used instead of maleic anhydride.
The average primary particle size (average particle size of primary particles) of the obtained nickel powder by SEM observation is 0.3 μm, and the particle size distribution is measured with a laser diffraction scattering type particle size distribution measuring device X100 (manufactured by Microtrack). the measurement _{results, D 10} is 0.30 _{.mu.m, D 50} is 0.44 _{.mu.m, D 90} is 0.68 .mu.m, and _{D max} was 1.41.
[0025]
The nickel powder was processed by FIB, and the cross section was taken and observed with an electron micrograph. There was almost no grain boundary, and it was highly crystalline as in Example 1.
XRD measurement was performed, and the crystallite size was determined by the Scherrer method. As a result, the 111th surface was 310mm, the 200th surface was 185mm, and the 220th surface was 199mm.
As a result of the purity analysis, C was 0.16% by mass, O was 0.54% by mass, and N was 0.001% by mass (10 ppm).
[0026]
Comparative Example 1
Nickel powder was obtained in the same manner as in Example 1 except that polyvinylpyrrolidone K30 (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of maleic anhydride.
That is, 400 mL of ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) and 1.91 g of polyvinyl pyrrolidone K30 as a dispersing agent were added to a 500 mL separable flask, and the mixture was stirred at a rotation speed of 350 rpm using a small stirrer, and polyvinyl pyrrolidone. K30 was dissolved.
[0027]
To the above solution, 38.29 g of nickel hydroxide (manufactured by OM Group) and 0.1 mL of palladium nitrate aqueous solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) prepared to 0.84 g / 1000 mL were added and heated to 190 ° C. . As the temperature increased, the liquid color in the container changed from green to black. By-product water, organic matter, and the like were distilled off through a distillation line. After reaching 190 ° C., sampling was performed every hour, and the progress of the reaction was confirmed by XRD. It was confirmed that nickel powder was produced by complete reduction in 5 hours.
[0028]
After completion of the reaction, the temperature was lowered to room temperature, and the solid and liquid were separated by suction filtration. The obtained solid (cake) was put into a 500 mL beaker, 300 mL of pure water was added and the mixture was vigorously stirred, and then the solid and liquid were separated by a suction filtration method. This operation was performed twice.
Next, the cake was put into a 500 mL beaker, 300 mL of methanol was added, and after vigorous stirring, the cake was collected by suction filtration and dried at 80 ° C. for 5 hours to obtain nickel powder.
[0029]
The average primary particle size (average particle size of primary particles) of the obtained nickel powder by SEM observation is 0.3 μm, and the particle size distribution is measured with a laser diffraction scattering type particle size distribution measuring device X100 (manufactured by Microtrack). the measurement _{results, D 10} is 0.36 _{.mu.m, D 50} is 0.64 _{.mu.m, D 90} is 2.82Myuemu, and _{D max} was 13.08Myuemu.
[0030]
The nickel powder was processed by FIB, and the cross section was taken and observed with an electron micrograph. It was nickel powder with many grain boundaries.
XRD measurement was performed, and the crystallite size was determined by the Scherrer method. As a result, the 111th surface was 237 mm, the 200th surface was 153 mm, and the 220th surface was 161 mm.
As a result of the purity analysis, C was 0.40% by mass, O was 1.26% by mass, and N was 0.028% by mass (280 ppm).
[0031]
Comparative Example 2
Nickel powder was obtained by the same treatment as in Example 1 except that maleic anhydride was not used.
In the SEM observation of the obtained nickel powder, the particle size is non-uniform (0.3 to 1.5 μm), the average primary particle size (average particle size of primary particles) is 0.8 μm, and the particle size distribution result of measurement by a laser diffraction scattering particle size distribution analyzer X100 (manufactured by Microtrac _{Inc.), D 10} is 0.76 _{.mu.m, D 50} is 1.35 _{.mu.m, D 90} is 2.58Myuemu, and _{D max} is 15.56μm Met.
[0032]
The nickel powder was processed by FIB, and the cross section was taken and observed with an electron micrograph. It was nickel powder with many grain boundaries.
XRD measurement was performed, and the crystallite size was determined by the Scherrer method. As a result, the 111th surface was 325 mm, the 200th surface was 195 mm, and the 220th surface was 202 mm. Further, as a result of purity analysis, C was 0.11% by mass, O was 0.35% by mass, and N was 0.0009% by mass (9 ppm).
[0033]
As is clear from the data of the above Examples and Comparative Examples, compared with Comparative Example 1 using polyvinyl pyrrolidone as a dispersant and Comparative Example 2 using no dispersant, Examples 1 to 1 of the present invention were used. In the case of No. 3 , nickel-free, high-crystallinity, high-purity nickel powder having a monodispersion with an average particle diameter of 0.05 to 1 μm is obtained.
[0034]
【The invention's effect】
Nickel powder obtained by the process of the present invention, as is apparent from the above examples, a nitrogen-free, the average particle size in the monodisperse 0.05 to 1 [mu] m, high crystallinity, a high purity nickel powder is there.
[Brief description of the drawings]
1 is an electron micrograph of a cross section processed by FIB of nickel powder obtained in Example 1. FIG.

Claims (5)

A powder selected from the group consisting of nickel salt powder and nickel hydroxide powder in a polyol containing a dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid , and a noble metal compound catalyst. A method for producing nitrogen-free nickel powder having an average particle size of 0.05 to 1 μm, comprising suspending and heating the powder to a temperature sufficient to reduce the powder to nickel powder. 2. The nitrogen-free composition according to claim 1, wherein the heating temperature is 85 ° C. or more and the boiling point is lower than the boiling point or decomposition temperature of the dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid, and lower than the boiling point of the polyol. Method for producing nickel powder. The method for producing a nitrogen-free nickel powder according to claim 1 or 2 , wherein the content of the dispersant selected from the group consisting of maleic anhydride, fumaric acid and n-hexanoic acid is 0.01 mass% or more of the amount of polyol. . The method for producing nitrogen-free nickel powder according to claim 1, 2 or 3, wherein maleic anhydride or fumaric acid is used.   The method for producing nitrogen-free nickel powder according to any one of claims 1 to 4, wherein the nitrogen content of the nitrogen-free nickel powder is 10 ppm or less.

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