KR102032009B1 - Nickel metal powder and process for producing nickel metal powder - Google Patents

Abstract

A metal nickel powder having a low content of coarse particles formed by aggregation of metal nickel powder particles is provided. And the average particle diameter 10nm to 1000nm, S / N ratio (X) and 3700cm ^-1 to 3600cm ^-1 of absorption in the absorption spectrum of the signal of 1200cm ^-1 to 900cm ^-1 in a Fourier transform infrared spectrophotometer provided with an MCT detector Metal nickel powder whose S / N ratio (Y) of a spectral signal is Y <=-1.0X + 23.0.

Description

Metal nickel powder and manufacturing method of metal nickel powder {NICKEL METAL POWDER AND PROCESS FOR PRODUCING NICKEL METAL POWDER}

TECHNICAL FIELD This invention relates to the manufacturing method of a metal nickel powder and a metal nickel powder. Specifically, It is related with the metal nickel powder with little content of the coarse particle formed by the aggregation of particle | grains, and its manufacturing method.

Metal nickel is much more stable than iron with respect to air and humidity, and is used as stainless steel for kitchens and tablewares because it is excellent in corrosion resistance and heat resistance. In addition, since it is excellent in heat dissipation characteristics and electrical characteristics, it is also used as a material for nickel-metal hydride batteries or lithium ion batteries, and is a multilayer ceramic capacitor (hereinafter, abbreviated as MLCC) which is indispensable as a part of a mobile phone or a PC. It is also used as an electrode material.

The MLCC has a structure in which a dielectric ceramic layer and a metal layer used as an internal electrode are alternately overlapped, and external electrodes are connected to both ends of the laminate. Here, as the material constituting the dielectric, a material having a high dielectric constant such as barium titanate, strontium titanate, yttrium oxide, etc. as a main component is used. On the other hand, as the metal constituting the internal electrode, precious metal powders such as silver, palladium, platinum and gold, alloys using these precious metal powders, or nonmetal powders such as nickel, cobalt, iron, molybdenum, tungsten and copper and these nonmetal powders An alloy using this is used. Among these, in recent years, the development of MLCC which uses metal nickel powder as an internal electrode material is actively performed.

In addition, in recent years, miniaturization of MLCC has been demanded due to the miniaturization of light weight of electronic devices. In miniaturization of MLCC, it is necessary to reduce the thickness of the dielectric layer and the electrode layer. As a result, the demand for fine-differentiating the particle size of the metal nickel powder to 1 μm or less, 0.5 μm or less and 0.2 μm or less is increasing year by year.

MLCC is generally manufactured by the following method. First, a dielectric powder, such as barium titanate, is mixed with an organic binder and suspended, which is molded into a sheet by the doctor blade method to prepare a dielectric green sheet. On the other hand, the metal powder for internal electrodes is mixed with organic compounds, such as an organic solvent, a plasticizer, and an organic binder, and forms a metal powder paste, and this is printed and dried on the said green sheet by the screen printing method. Subsequently, after laminating | stacking and crimping | stacking this sheet, after removing an organic component by heat processing, it bakes at the temperature of 1300 degreeC or more or more. Thereafter, external electrodes are baked at both ends of the fired body to obtain MLCC.

In the MLCC manufacturing method as described above, if coarse particles formed by agglomeration of the metal powder are present in the metal powder in the metal powder paste, there is a problem of causing a short circuit between the electrodes through the dielectric layer. .

As the countermeasure, for example, (in some cases it abbreviated as follows, FT-IR) In Patent Document 1, infrared absorption spectrum where the signal using a nickel powder does not exhibit an absorption peak in 3700cm ^-1 to 3600cm ^-1 It is proposed that the aggregation of powders can be suppressed by this. Vibrations in this range belong to OH groups chemically bonded to metallic nickel. Such metal nickel powder can be obtained by heat-processing the metal nickel powder obtained by the vapor phase method etc. in 200 degreeC-400 degreeC oxidizing atmosphere.

However, in the above-described conventional method, although its effect is improved for the purpose of reducing and improving coagulation to coarse particles, a method of preventing coagulation into coarse particles is not necessarily sufficient.

Japanese Patent No. 3787032

Accordingly, an object of the present invention is to provide a metal nickel powder having a small content of coarse particles formed by agglomeration of metal nickel powder particles and a method for producing the same.

The present inventors have diligently studied the coarse particles of the metal nickel powder, and found that the coarse particles are generated by coagulation of the nickel powder due to the presence of a small amount of silicic acid in addition to the hydroxide on the surface of the metal nickel powder. The present invention has been completed.

That is, the present invention, the average particle diameter is 10nm to 1000nm, S / N ratio (X) and 3700cm ^-1 of the absorption spectrum of the signal of 1200cm ^-1 to 900cm ^-1 in a Fourier transform infrared spectrophotometer provided with an MCT detector S / N ratio (Y) of the absorption spectrum signal of 3600 cm ^-1 ,

Y≤-1.0X + 23.0

It is a metal nickel powder characterized by the above-mentioned.

Moreover, this invention is a pure water which produced | generated the metal nickel powder from a nickel compound by the gas phase method or the liquid phase method, cooled the said metal nickel powder, performed electrostatic adsorption filtration, and reduced the silicon content as said manufacturing method of said metal nickel powder. A carbonic acid solution is prepared by dissolving carbon dioxide in the carbon dioxide solution, and treating the metal nickel powder with the carbonic acid solution.

The metal nickel powder which concerns on this invention is a metal nickel powder which does not contain the coarse particle which the metal nickel powder aggregates, and is suitable for the internal electrode of a multilayer ceramic capacitor.

1 is a view showing the FT-IR absorption spectrum of the metal nickel powder of Example 1 of the present invention.
2 is a diagram showing an FT-IR absorption spectrum of the metal nickel powder of Comparative Example 1 of the present invention.
3 is a diagram showing an FT-IR absorption spectrum of Reference Example 1 (metal nickel powder of Comparative Example 1) of the present invention.
4 is a view showing the results of Examples 1 to 7, and Comparative Examples 1 to 3 of the present invention.
5 is a view showing an apparatus for producing metal nickel powder used in Examples and Comparative Examples of the present invention.

Metallic nickel powder of the present invention, the average particle diameter is 10nm to 1000nm, 1200cm ^-1 to the S / N ratio (X) and 3700cm of the absorption spectrum of the signal 900cm ^-1 in a Fourier transform infrared spectrophotometer provided with an MCT detector The S / N ratio (Y) of the absorption spectrum signal of ^-1 to 3600 cm ^-1 is

Y≤-1.0 × X + 23.0

It is a metal nickel powder characterized by the above-mentioned. Preferably,

Y≤-1.0 × X + 16.7

It is a metal nickel powder characterized by the above-mentioned. By setting it as this range, the metal nickel powder with favorable dispersibility which does not contain the coarse particle formed by aggregation can be obtained.

10 nm-1 micrometer is preferable, and, as for the average particle diameter of the metal nickel powder of this invention, it is more preferable if it is microparticles | fine-particles of the range of 10 nm-0.4 micrometer. By setting it as this range, it is suitable for using for a electrically conductive paste. In addition, the particle size of the metal nickel powder of this invention is the diameter of the minimum circle which wraps each particle.

Absorption spectrum of 1200cm ^-1 ~ 900cm ^-1 in the infrared absorption spectrum analysis by a Fourier transform infrared spectrophotometer of the metallic nickel powder of the present invention, Si-O-Si (catenary), (Si-O-Si ) _{3 (cyclic), (SiO-Si) 4} ( cyclic), (SiO-Si) _n (cyclic), SiO ₃ ^{2 -} is the peak attributable to the skeleton vibration of the SiO-Si of the (silicate) . (Reference: `` Handbook of Infrared and Raman Spectra of Inorganic Compounds and Organic Salts (4-Volume set) '', `` NBColthup etal., Introduction to Infrared and Raman Spectroscopy (Third Edition), '' K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds (FOURTH EDITION), `` Hiroguchi Hiroshi Infrared Absorption Scenario General Sankyo Publishing Company '', `` Application of Absorption Spectrum to Organic Compounds Tokyo Kagaku Tojin '', `` Introduction to Instrument Analysis Kagaku Tojinsa '' ). Also, absorption spectrum of 3700cm ^-1 to 3600cm ^-1 is a peak attributed to the Ni (OH) ₂ (Reference: Japanese Patent Publication 2010-237051 gazette).

The S / N ratio of the metal nickel powder of this invention is calculated | required by the following method. 1200cm ^-1 to the absorbance of the absorption spectrum of the 900cm ^-1, 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum of the absorbance, a ratio of the absorbance is not the base line variations do not have the absorption spectrum range. In general, the absorbance of the region having no absorption spectrum and the baseline is not deformed, it is preferable to select a wave number that is not affected by moisture and carbon dioxide, for example, 2200cm ^-1 to 1950cm ^-1 It is preferable to select within the range of. The absorbance calculated | required the peak area value in 50 cm <^-1> units of the said frequency range, and made it the average value.

In addition, since SiOH, SiO _n , and Ni (OH) ₂ contained in the metal nickel powder of this invention are trace amounts, the detector of a Fourier Transform infrared spectrophotometer has a high sensitivity type, and uses an MCT detector type. The detector is composed of a semiconductor element composed of mercury, cadmium, and tellurium. When the detector is filled with liquid nitrogen and filled with a detector, information is obtained with high sensitivity and is effective for trace substances. In addition, it is preferable that the gas of various components does not enter in the atmosphere of the sample chamber under measurement, and the inside of a sample chamber is preferable under a dry atmosphere gas or a vacuum state. In addition, when measuring under dry atmosphere gas, when a dew point is not maintained at -50 degrees C or less, the signal derived from an OH group will appear, and it needs to be careful because it interferes with an analysis. The total number of times of integration is sufficient as 128 times or more as long as a dew point is maintained. As for the measurement resolution, 4 cm <^-1> or less is preferable.

For example, the intensity | strength of the absorption spectrum of the Fourier transform infrared spectroscopy of this invention is calculated | required by the following measurement conditions.

Model name: Model Nicolet 6700 (manufactured by Thermo Fisher Scientific)

Detector: MCT Detector

Measurement method: Diffuse reflection method

Measurement condition: Resolution 4cm ^-1 , accumulation times 256 times

Light source: infrared absorption light (IR)

Gas in sample chamber: Dry nitrogen (dew point: -72 ° C)

Beam Splitter: KBr

Background integration count, resolution: 256 times, 4 cm ^-1

Method: K-M Conversion

The nickel powder of this invention can be manufactured by well-known methods, such as a gas phase method and a liquid phase method, for example. In particular, the gas phase reduction method of contacting nickel chloride gas and reducing gas to generate nickel powder, or the spray pyrolysis method of thermally decomposing a pyrolytic nickel compound by thermal decomposition, can easily control the particle diameter of the fine metal powder to be produced. Moreover, it is preferable at the point that spherical particle | grains can be manufactured efficiently. Moreover, it is common that the particle size of nickel powder is 10 nm-1 micrometer.

In the nickel powder gas phase reduction method, a gas of evaporated nickel chloride and a reducing gas such as hydrogen may be reacted. Nickel chloride gas may be produced by heating and evaporating solid nickel chloride. However, in view of preventing oxidation or absorption of nickel chloride and energy efficiency, chlorine gas is brought into contact with metal nickel to continuously generate nickel chloride gas, and the nickel chloride gas is directly supplied to a reduction process, and then reducible. It is advantageous to produce nickel fine powder by contacting with gas to continuously reduce nickel chloride gas.

In the manufacturing process of the nickel powder by a gas phase reduction reaction, a nickel atom is produced at the moment when nickel chloride gas and a reducing gas contact, and ultrafine particles generate | generate and grow by colliding and aggregating nickel atoms. And the particle diameter of the fine nickel powder to produce | generate is determined by conditions, such as partial pressure of nickel chloride gas and temperature in a reduction process. According to the method for producing nickel powder as described above, since nickel chloride gas in an amount corresponding to the supply amount of chlorine gas is generated, the amount of nickel chloride gas supplied to the reduction process can be adjusted by controlling the supply amount of chlorine gas. Particle diameter of the nickel fine powder produced | generated can be controlled.

In addition, since the metal chloride gas is generated by the reaction between the chlorine gas and the metal, it is different from the method of generating the metal chloride gas by heat evaporation of the solid metal chloride, and the use of the carrier gas can be reduced, Depending on manufacturing conditions, it is also possible not to use. Therefore, the gas phase reduction reaction can reduce the production cost by reducing the amount of the carrier gas used and the heating energy.

Moreover, the partial pressure of nickel chloride gas in a reduction process can be controlled by mixing an inert gas with the nickel chloride gas produced at the chloride process. Thus, by controlling the supply amount of chlorine gas or the partial pressure of nickel chloride gas supplied to a reduction process, the particle size of nickel powder can be controlled, the nonuniformity of a particle size can be suppressed, and a particle size can be set arbitrarily.

The conditions for producing the nickel powder by the vapor phase reduction method as described above are arbitrarily set so as to have an average particle diameter of 1 μm or less. For example, the particle size of the metal nickel, which is a starting material, is preferably about 5 to 20 mm in granules, blocks, plates, and the like. In addition, the purity is preferably 99.5% or more. The metal nickel is first reacted with chlorine gas to generate nickel chloride gas. The temperature at that time is 800 ° C or higher in order to sufficiently advance the reaction, and 1453 ° C or lower, which is the melting point of nickel. In consideration of the reaction rate and the durability of the chlorine furnace, a practical range of 900 ° C to 1100 ° C is preferable.

Subsequently, the nickel chloride gas is directly supplied to a reduction step and brought into contact with a reducing gas such as hydrogen gas. An inert gas such as nitrogen or argon is mixed in an amount of 1 to 30 mol% with respect to the nickel chloride gas. You may introduce mixed gas into a reduction process. Moreover, chlorine gas can also be supplied to a reduction process with nickel chloride gas or independently. Thus, by supplying chlorine gas to a reduction process, the partial pressure of nickel chloride gas can be adjusted, and it becomes possible to control the particle diameter of the nickel powder to produce | generate. Although the temperature of a reduction reaction should just be sufficient as the temperature sufficient for completion | finish of reaction, since producing a solid nickel powder is easy to handle, below melting | fusing point of nickel is preferable, and considering economical efficiency, 900 degreeC-1100 degreeC is practical.

After the nickel powder subjected to the reduction reaction is produced, the produced nickel powder is cooled next. At the time of cooling, in order to prevent generation | occurrence | production of secondary particle by the aggregation of the primary particle | grains of the nickel which were produced | generated, and to obtain nickel powder of a desired particle size, inert gas, such as nitrogen gas, was blown in near 1000 degreeC which completed the reduction reaction. It is preferable to rapidly cool the gas stream to about 400-800 degreeC. Thereafter, the produced nickel powder is separated and recovered by, for example, a bug filter or the like.

In the method for producing nickel powder by spray pyrolysis, pyrolytic nickel compounds are used as raw materials. Specifically, nitrates, sulfates, oxynitrates, oxysulfates, chlorides, ammonium complexes, phosphates, carbonates and alkoxy 1 type, or 2 or more types of compounds, etc. are contained. A fine liquid droplet is formed by spraying the solution containing this nickel compound, and water, alcohol, acetone, ether and the like are used as the solvent at this time. In addition, the spraying method is performed by a spraying method such as an ultrasonic wave or a double jet nozzle. In this way, fine droplets are dropped and heated to a high temperature to thermally decompose the metal compound to produce nickel powder. The heating temperature at this time is more than the temperature which the specific nickel compound used thermally decomposes, Preferably it is near melting | fusing point of a metal.

In the method for producing fine metal powders by the liquid phase method, an aqueous nickel solution containing nickel sulfate, nickel chloride or a nickel complex is added to an alkali metal hydroxide such as sodium hydroxide, and the like is brought into contact with each other to produce a nickel hydroxide. The nickel hydroxide is reduced with a reducing agent to obtain metal nickel powder. The metal nickel powder thus produced is subjected to a pulverization treatment as necessary in order to obtain uniform particles.

For example, the nickel powder obtained by the above method is suspended and suspended in a carbonated aqueous solution under specific conditions in which pH and temperature are controlled. By treating with a carbonated aqueous solution, impurities such as chlorine adhering to the surface of nickel are sufficiently removed, and fine particles formed away from the surface by friction between particles of hydroxides such as nickel hydroxide present on the surface of nickel powder or particles are removed. A uniform film of nickel oxide can be formed on the surface. For example, carbonic acid gas may be blown into the method of washing with a carbonated aqueous solution, or water slurry after pure water washing, or it may be added and treated.

In the treatment with this carbonated aqueous solution, carbonic acid aqueous solution having a silicon content of 15 wtppm or less or carbon dioxide dissolved in a pure water having a silicon content of 15 wtppm or less is used, and the treatment conditions are a temperature of 0 ° C or higher and less than 30 ° C and pH 4 or higher and lower than 6. By treatment under such conditions, a uniform oxide film is formed on the surface of the nickel powder after drying, and adhesion of silicic acid to the nickel powder is suppressed, so that generation of coarse particles can be suppressed.

In addition, the RO reverse osmosis membrane, an ion exchanger, and the filter provided with the electrostatic adsorption function are used for silicon removal from pure water. Until now, it was common to filter using RO reverse osmosis membrane and ion exchanger, but it was difficult to cope with silicic acid which cannot be removed by RO reverse osmosis membrane and ion exchanger. However, as a result of intensive studies by the present inventors, it has been found that silicic acid, which cannot be removed by the RO reverse osmosis membrane and ion exchanger, consists of colloidal silica or the like. Since the zeta potential of the colloidal silica is negatively charged, it has been found that the colloidal silica can be reduced by using a filter provided with a filter in which the zeta potential of the surface is positively charged. The material of the filter can be applied to various kinds of materials, such as hydrophilic nylon, olefin polymer or polyester, but there is no particular limitation as long as the zeta potential of the surface is positive (+). The silicic acid contained in the pure water cannot be sufficiently removed by a reverse osmosis membrane and an ion exchanger used in ordinary pure water production. Pure water or a carbonated aqueous solution having a silicon content of 15 wtppm or less can be obtained by further treating with a filter having a filter in which the zeta potential of the surface is charged with (+). For example, such a filter is commercially available as a holder filter plate type (Advantech Toyo Co., Ltd.), a brand name: Posidyne UP (Japan Pole Co., Ltd.), etc. which have a multipurpose tank.

In this manner, after the nickel powder is carbonated, the nickel powder is dried. A well-known method can be employ | adopted as a drying method, Specifically, airflow drying, heat drying, vacuum drying, etc. which contact and dry in contact with hot gas are mentioned. Among these, airflow drying is a preferred method because there is no wear of the oxide film due to contact between the particles. Moreover, in order to form a homogeneous oxide film on the surface of nickel powder, it is preferable to remove moisture and to dry in a short time.

The dried nickel powder is further subjected to heat treatment in an environment in which the oxygen partial pressure is controlled to control the amount of Ni (OH) _{2 on the} surface of the powder. For example, heat processing is performed in the atmosphere which controlled oxygen partial pressure, stirring, using a flow stirrer. The heat treatment temperature and the heat treatment time are determined according to the size of the nickel powder and the thickness of the oxide film, and the heat treatment temperature at this time is usually 200 to 400 ° C, preferably 200 to 300 ° C, more preferably 200 to 250 ° C. Moreover, heat processing time is 1 minute-10 hours normally.

The nickel powder thus obtained is further dispersed in a solvent such as water as needed. Thereafter, coarse powder and connecting lip are removed by passing the filter. Since the dispersibility of nickel powder is favorable, coarse powder and a connection grain can be removed efficiently. A well-known method can be used for filtration, The filter can use the organic polymer (nylon, polypropylene, tetrafluoroethylene resin, cellulose, melamine, phenol resin, acryl, etc.), a metal, an inorganic compound filter have. Moreover, in order to raise the efficiency of a filter, you may perform other classification means, such as the classification means (liquid cyclone) using a centrifugal force, before letting a filter pass.

Next, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited at all by the following example.

Example

The average particle diameter, FT-IR measurement, silicon concentration, and aggregation in the present Example were evaluated by the following method.

a. Evaluation of Average Particle Size

The photograph of the nickel powder was taken with the scanning electron microscope, the particle diameter of 200 particle | grains was measured from the photograph, and the average value was computed. In addition, the particle diameter was made into the diameter of the minimum circle which wraps particle | grains.

b. FT-IR measurement

FT-IR measurement was performed on condition of the following.

Model name: Model Nicolet 6700 (manufactured by Thermo Fisher Scientific)

Detector: MCT Detector

Measurement method: Diffuse reflection method

Measurement condition: Resolution 4cm ^-1 , accumulation times 256 times

Light source: infrared absorption light (IR)

Gas in sample chamber: Dry nitrogen (dew point: -72 ° C)

Beam Splitter: KBr

Background accumulation total: 256 times

Resolution: 4cm ^-1

Interpretation: K-M Conversion

The measurement sample was prepared as follows. Metal Nickel Powder, Caliber 7mm After filling the cylindrical sample jig with phosphorus bottom, the metal nickel powder was pushed horizontally at the top of the cylindrical sample jig to be even. This cylindrical sample jig was set in an FT-IR apparatus so that a sample might not flow.

S / N ratio, 1200cm ^-1 to the absorbance of the absorption spectrum of the absorbance of 900cm ^-1 absorbance or absorption spectrum 3700cm ^-1 to 3600cm ^-1 of, that is not the base line variations do not have absorption spectra region (2200cm ^{- 1} to 1950 cm ^-1 ). In addition, the absorbance calculated | required the peak area value in 50 cm <^-1> unit of said frequency range, and made it the average value.

c. Silicon concentration measurement

By ion chromatography, the silicon content in the pure water and the carbonated aqueous solution was measured.

Model name: Model IC-2010 (manufactured by Tosoh, Inc.) (detector: CM detector)

Analysis mode: CM; Range (5000 μS-1 / 2) non-suppressor mode

Column: TSKgel SuperIC-AP 4.6mmID × 7.5cm

Eluent: 2 mM KOH

Flow rate: 0.8 mL / min

Column temperature: 40 degrees Celsius

d. Evaluation of Cohesion

100 g of metal nickel powder is charged into 1900 g of pure water, and a 5 wt% metal nickel powder slurry is prepared. Next, suction filtration is performed by a filter having a body size of 1 m. The metal nickel powder remaining on the filter was dried at 120 ° C. for 30 minutes in an inert gas atmosphere, and the weight thereof was measured, and the passing rate thereof ((100 (g)-weight of nickel powder on the filter (g)) / 100 (g)) The aggregation was evaluated by. A pass rate of 90% or more is excellent (indicated by "○" in Table 1 and FIG. 4), 80% or more is good (indicated by "△" in Table 1 and FIG. 4), and less than 80% is rejected (Table 1 and FIG. In 4, it is represented by "x".

Example 1 (Si minimum, Ni (OH) minimum)

Metal nickel powder was produced by the method similar to the method of Example 1 of Unexamined-Japanese-Patent No. 4286220. In addition, prior to the preparation of the metal nickel powder, pure water having different silicon concentrations below was prepared.

Pure A: Silicon Concentration 65wtppm

Pure water B: The pure water A was processed by the filtration apparatus (holder filter plate type with a versatile tank type (made by Advantech Toyo Co., Ltd.)) with the filter which the zeta potential of the surface charged to (+). Silicon concentration is 3 wtppm.

In the chloride furnace 1 of the apparatus for producing a metal nickel powder shown in FIG. 5, a metal nickel M having an average particle diameter of 5 mm was filled, and the furnace 11 temperature was set to 1100 ° C. by the heating means 11. Then, chlorine gas was supplied from the nozzle 12 into the chloride furnace 1, and the metal nickel short M was chlorided to generate nickel chloride gas. Thereafter, the mixture was diluted and mixed with nitrogen gas supplied from the nozzle 13. And the mixed gas of nickel chloride gas and nitrogen gas was introduce | transduced from the nozzle 22 into the reduction furnace 2 which made into the furnace atmosphere temperature of 1000 degreeC with the heating means 21. As shown in FIG.

At the same time, hydrogen gas was supplied from the nozzle 23 into the reduction furnace 2 to reduce nickel chloride gas to obtain nickel powder P. Moreover, the nitrogen gas supplied from the nozzle 24 was made to contact the metal nickel powder P produced | generated at the reduction process, and metal nickel powder P was cooled. A part of metal nickel powder P was sampled and the average particle diameter was measured after water washing, and the average particle diameter of metal nickel powder P was 0.3 micrometer.

Next, the mixed gas consisting of nitrogen gas-hydrochloric acid vapor-metal nickel powder P was led to a washing tank filled with pure water B, the metal nickel powder was separated and recovered, and washed with pure water B (pure washing).

Next, carbonic acid gas was blown into the metal nickel powder slurry to pH 4.0, and 60 minutes of processing was performed at 25 degreeC as a carbonic acid solution (carbonated aqueous solution process).

After drying the metallic nickel powder treated with the aqueous carbonic acid solution, the mixture was treated at 200 ° C. for 30 minutes in the air (heating treatment) to obtain a metallic nickel powder. The average particle diameter of the metal nickel powder was 0.3 μm.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown. Moreover, the result of FT-IR was shown in FIG.

<Example 2>

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 5 wtppm was used, and the heat treatment after drying was carried out at 250 ° C for 30 minutes instead of for 30 minutes at 200 ° C. In the same manner, a metal nickel powder was obtained. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 3>

Metal nickel powder was obtained like Example 1 except having carried out the heat processing after drying at 30 degreeC for 30 minutes instead of 30 degreeC at 200 degreeC. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 4>

Metal nickel powder was obtained in the same manner as in Example 1 except that pure water having a silicon concentration of 14 wtppm was used instead of pure water B having a silicon concentration of 3 wtppm. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Example 5

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 6 wtppm was used, and the heat treatment after drying was carried out at 150 ° C for 30 minutes instead of for 30 minutes at 200 ° C. In the same manner, a metal nickel powder was obtained. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 6>

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 5 ppm was used, except that the heat treatment after drying was treated at 150 ° C for 30 minutes instead of 30 minutes at 200 ° C. In the same manner, a metal nickel powder was obtained.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 7>

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 4 wtppm was used, and the heat treatment after drying was carried out at 150 ° C for 30 minutes instead of for 30 minutes at 200 ° C. In the same manner, a metal nickel powder was obtained. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 8>

Metal nickel powder was obtained in the same manner as in Example 1 except that pure water at a silicon concentration of 7 wtppm was used instead of pure water at a silicon concentration of 3 wtppm. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Example 9

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 14 wtppm was used, and, except that the heat treatment after drying was treated at 250 ° C for 30 minutes instead of at 30 ° C for 30 minutes, In the same manner, a metal nickel powder was obtained. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Comparative Example 1

Example 1 except that pure water A having a silicon concentration of 45 wtppm was used instead of pure water B having a silicon concentration of 3 wtppm, and heat treatment after drying was performed at 150 ° C. for 30 minutes instead of 200 minutes for 30 minutes. In the same manner as the above, a metal nickel powder was obtained. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Comparative Example 2

Metal nickel powder was obtained in the same manner as in Example 1 except that pure water having a silicon concentration of 49 wtppm was used instead of pure water B having a silicon concentration of 3 wtppm. In addition, the silicon concentration of pure water was prepared by mixing pure water A and pure water B. FIG.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Comparative Example 3

Instead of pure water B with a silicon concentration of 3 wtppm, pure water with a silicon concentration of 65 wtppm was used, and the heat treatment after drying was carried out at 250 ° C for 30 minutes instead of for 30 minutes at 200 ° C. In the same manner, a metal nickel powder was obtained.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

<Example 10>

A metal nickel powder Q was produced in the same manner as in Example 1 except that the dilution amount of the nitrogen gas from the nozzle 13 was increased. A part of metal nickel powder Q was taken out and the average particle diameter was measured after water washing, but the average particle diameter of metal nickel powder Q was 0.15 micrometer. Pure water washing | cleaning, a carbonated aqueous solution process, and heat processing were performed like this metal nickel powder Q similarly to Example 1.

In Table 1, the S / N ratio (Y), aggregation of the S / N ratio (X), the absorption spectrum signal of 3700cm ^-1 to 3600cm ^-1 of the absorption spectrum signal of 1200cm ^-1 to 900cm ^-1 of metal nickel powder The evaluation result was shown.

Reference Example 1

The metal nickel powder of the comparative example 1 was evaluated with the following FT-IR apparatus (model name: model Nicolet6700 (made by Thermo Fisher Scientific)) which has a TGS detector, and is shown in FIG.

The result of Example 1-Example 9 and Comparative Example 1-Comparative Example 3 was shown in FIG. In Figure 4 a, S / N ratio of the signal absorption spectrum of the Fourier transform infrared spectrophotometer 1200cm ^-1 to 3700cm ^-1 and 900cm S / N ratio (X) of the absorption spectrum signal of ^-1 to 3600cm ^-1 in the ( It turns out that the metal nickel powder which Y) satisfy | fills Y <= 1.0 * X + 23.0 does not have aggregation, and shows favorable dispersibility. In particular, it can be seen that the metal nickel powder satisfying Y ≦ −1.0 × X + 16.7 exhibits more excellent dispersibility.

According to the present invention, a metal nickel powder containing almost no coarse particles formed by agglomeration of nickel particles is obtained, and is suitable as nickel powder for internal electrodes of a multilayer ceramic capacitor.

1: chloride
11: heating means
12: chlorine gas supply pipe
13: Nitrogen gas supply pipe
2: reduction furnace
21: heating means
22: Nozzle
23: hydrogen gas supply pipe
24: cooling gas supply pipe
M: Nickel Raw Material
P: nickel powder

Claims (4)

And the average particle diameter 10nm to 1000nm, S / N ratio (X) and 3700cm ^-1 to 3600cm ^-1 of absorption in the absorption spectrum of the signal of 1200cm ^-1 to 900cm ^-1 in a Fourier transform infrared spectrophotometer provided with an MCT detector The S / N ratio (Y) of the spectral signal is
Y≤-1.0X + 23.0
Metal nickel powder, characterized in that. The method according to claim 1,
The S / N ratio (X) and the S / N ratio (Y)
Y≤-1.0X + 16.7
Metal nickel powder, characterized in that. As a manufacturing method of the metal nickel powder of Claim 1 or 2,
Metal nickel powder is produced from the nickel compound by vapor phase or liquid phase method,
To cool the metal nickel powder,
Electrostatic adsorption filtration to dissolve carbon dioxide in pure water having reduced silicon content to prepare a carbonated aqueous solution,
The metal nickel powder is treated with the carbonated aqueous solution. The method according to claim 3,
A silicon nickel powder is 15 wtppm or less by said electrostatic adsorption filtration, The manufacturing method of the metal nickel powder characterized by the above-mentioned.