JP2018154883A - Method for producing a nickel powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a nickel powder allowing for efficiently obtaining a nickel powder while continuously hydrogen-reducing a nickel sulfate ammine complex solution with high rate of reduction.SOLUTION: A method for producing a nickel powder is characterized by preparing a dispersant-containing mixed solution by adding, to a nickel sulfate ammine complex solution including ammonium sulfate, polyacrylic acid in an amount for a concentration of 0.01 g/L or greater and 10 g/L or smaller with respect to the nickel sulfate ammine complex solution, next supplying the dispersant-containing mixed solution into a reaction vessel and contacting it with a hydrogen gas that has been blown into the reaction vessel, producing a nickel powder through a reduction treatment of nickel complex ions in the nickel sulfate ammine complex solution, and discharging an obtained slurry including a nickel powder to an outside of the reaction vessel.SELECTED DRAWING: None

Description

本発明は、硫酸アンモニウムを含む硫酸ニッケルアンミン錯体溶液に高温高圧下で水素ガスを接触させてニッケルイオンを還元しニッケル粉を得る方法に関する。   The present invention relates to a method for obtaining nickel powder by reducing nickel ions by bringing hydrogen gas into contact with a nickel sulfate ammine complex solution containing ammonium sulfate under high temperature and pressure.

湿式製錬プロセスを用いてニッケルの粉末を工業的に製造する方法として、特許文献１に示すように、ニッケルを含有する原料を硫酸溶液に溶解後、溶解液に含有する不純物を除去する浄液工程を経て、得た硫酸ニッケル溶液にアンモニアを添加してニッケルのアンミン錯体を形成させ、次いでこの硫酸ニッケルアンミン錯体溶液をオートクレーブなどの高温・高圧の反応容器に入れ、水素ガスを供給して硫酸ニッケルアンミン錯体溶液中のニッケル錯イオンを還元し、ニッケル粉を製造する方法が知られている。   As a method for industrially producing nickel powder using a hydrometallurgical process, as shown in Patent Document 1, after dissolving a nickel-containing raw material in a sulfuric acid solution, a purified solution for removing impurities contained in the solution Through the process, ammonia is added to the obtained nickel sulfate solution to form a nickel ammine complex, and then this nickel sulfate ammine complex solution is placed in a high-temperature and high-pressure reaction vessel such as an autoclave, and hydrogen gas is supplied to produce sulfuric acid. A method for producing nickel powder by reducing nickel complex ions in a nickel ammine complex solution is known.

上記のような製造方法の実施に際しては、高温・高圧の反応で行われることから、取扱いやすさや装置コストの観点からバッチ式を用いた製造方法を用いることが多かった。
しかしバッチ式の製造方法では、反応容器を開け、溶液を装入し、密栓して昇温し、温度と圧力を制御し、水素ガスを吹き込んで還元し、冷却し、反応物を取り出す一連の操作を段階ごとに行う必要があり、多大な手間と時間を要し、稼働率が低くなり工業的には効率的でなかった。 Since the above-described production method is carried out by a reaction at a high temperature and a high pressure, a production method using a batch method is often used from the viewpoint of ease of handling and apparatus cost.
However, in the batch-type manufacturing method, a reaction vessel is opened, a solution is charged, and the temperature is increased by sealing, the temperature and pressure are controlled, hydrogen gas is blown in to reduce, cool, and the reaction product is taken out. It was necessary to perform the operation step by step, requiring a lot of labor and time, and the operating rate was low, which was not industrially efficient.

さらに、上記のようなバッチ反応では、反応前後の加熱途中や降温中の温度変化の影響などが無視できず、この間にスケーリングと称する不均一な析出や粒径のばらつきが生じることがある。また粗大なニッケル粉が混じりやすいが、不均一なニッケル粉が生成すると、ハンドリング時に設備の摩耗や閉塞が発生しやすくなって稼働率が低下する。このためにスケーリングを除去する手間も増加し、設備稼動率を維持しながら製品品質を一定に保つのは難しかった。   Further, in the batch reaction as described above, the influence of temperature change during heating before and after the reaction or during temperature reduction cannot be ignored, and during this time, non-uniform precipitation called “scaling” and particle size variation may occur. Coarse nickel powder is likely to be mixed, but if non-uniform nickel powder is generated, the equipment is likely to be worn or clogged during handling, resulting in a reduction in operating rate. For this reason, the effort to remove the scaling has increased, and it has been difficult to keep the product quality constant while maintaining the equipment operation rate.

そこで、スケーリングを防止し均一なニッケル粉を得るために、水素還元前に種となる結晶（種晶）を添加し、併せてポリアクリル酸やその塩などの分散剤を添加して種の成長が偏在しないようにする試みが行われてきた。
しかし分散剤は適切な使用範囲があり、不適切な添加量ではニッケルを還元する反応率（還元率）が低下する問題がある。 Therefore, in order to prevent scaling and obtain uniform nickel powder, seed crystals (seed crystals) are added before hydrogen reduction, and dispersants such as polyacrylic acid and its salts are added to grow seeds. Attempts have been made to ensure that there is no uneven distribution.
However, there is a problem that the dispersant has an appropriate range of use, and if the addition amount is inappropriate, the reaction rate (reduction rate) for reducing nickel is lowered.

さらに種晶は、製品の一部を繰り返して用いたり、別に専用の工程を設けて製造することが多く、繰り返すことによる系内仕掛量の増加や、設備コストや手間が増加するなどの課題があった。
このように連続して水素還元して均一なニッケル粉を効率よく得るのは容易でなかった。 In addition, seed crystals are often manufactured by repeatedly using a part of the product or by providing a separate dedicated process, and there are problems such as an increase in the amount of work in the system due to repetition and an increase in equipment costs and labor. there were.
Thus, it was not easy to efficiently obtain uniform nickel powder by continuous hydrogen reduction.

特開２０１５−１４０４８０号公報JP2015-140480A

本発明は、硫酸アンミン錯体溶液を高い還元率を以て連続して水素還元を行いつつも、効率よくニッケル粉を得るニッケル粉の製造方法を提供しようとするものである。   The present invention intends to provide a method for producing nickel powder that efficiently obtains nickel powder while continuously hydrogen-reducing the ammine sulfate complex solution with a high reduction rate.

上記の課題を解決する本発明の第１の発明は、硫酸アンモニウムを含む硫酸ニッケルアンミン錯体溶液に、前記硫酸ニッケルアンミン錯体溶液に対して０．０１ｇ／Ｌ以上、１０ｇ／Ｌ以下の濃度となる量のポリアクリル酸を分散剤として含有した分散剤入り混合溶液を作製し、次いで前記分散剤入り混合溶液を、反応容器内に供給し、前記反応容器内に吹き込まれていた水素ガスに連続的に接触させ、前記硫酸ニッケルアンミン錯体溶液中のニッケル錯イオンを還元処理してニッケル粉を生成した後、得られたニッケル粉を含むスラリーを、前記反応容器の外に排出することを特徴とするニッケル粉の製造方法である。   1st invention of this invention which solves said subject is the quantity used as the density | concentration of 0.01 g / L or more and 10 g / L or less with respect to the said nickel sulfate ammine complex solution in the nickel sulfate ammine complex solution containing ammonium sulfate. A mixed solution containing a dispersant containing polyacrylic acid as a dispersant is prepared, and then the mixed solution containing the dispersant is supplied into the reaction vessel and continuously into the hydrogen gas blown into the reaction vessel. The nickel, wherein the nickel complex ions in the nickel sulfate ammine complex solution are subjected to reduction treatment to produce nickel powder, and then the resulting slurry containing the nickel powder is discharged out of the reaction vessel. It is a manufacturing method of powder.

本発明の第２の発明は、第１の発明における還元処理において、前記硫酸ニッケルアンミン錯体溶液を水素ガスに接触させる時間が、５分から１２０分間になるように、前記反応容器内に水素ガスを吹き込むと共に、前記分散剤入り混合溶液を前記反応容器内に供給し前記反応容器の外に排出することを特徴とするニッケル粉の製造方法である。   According to a second aspect of the present invention, in the reduction treatment according to the first aspect of the present invention, hydrogen gas is introduced into the reaction vessel so that the time for contacting the nickel sulfate ammine complex solution with hydrogen gas is 5 minutes to 120 minutes. The nickel powder manufacturing method is characterized in that, while blowing, the mixed solution containing a dispersant is supplied into the reaction vessel and discharged out of the reaction vessel.

本発明の第３の発明は、第１及び第２の発明における還元処理が、２．５〜３．５ＭＰａの範囲の圧力下で、１５０〜１８５℃の温度範囲に維持されて行われることを特徴とするニッケル粉の製造方法である。   The third invention of the present invention is that the reduction treatment in the first and second inventions is performed under a pressure in the range of 2.5 to 3.5 MPa and maintained in a temperature range of 150 to 185 ° C. It is the manufacturing method of the nickel powder characterized.

本発明によれば、還元処理時に発生するスケーリングや不均一な核生成を抑制しつつ還元処理が可能となり、効率よく高い還元率でニッケル粉を得ることができるようになった。   According to the present invention, it is possible to perform a reduction process while suppressing scaling and non-uniform nucleation that occur during the reduction process, and nickel powder can be obtained efficiently and at a high reduction rate.

従来のように種結晶を添加して反応を促進させるプロセスでは別途種結晶を製造する工程を必要とし高コストであった。
上記種結晶を利用する製法に対して本発明の方法は、分散剤のポリアクリル酸を、ポリアクリル酸溶液やポリアクリル酸塩の形で、その所定量をニッケルの錯体溶液に添加して水素ガスを吹き込むことで、溶液中において水素ガスで還元されて析出した微細なニッケル粉が、種結晶として利用可能であることを見出し、完成に至ったものである。そのため、本発明は種結晶を製造する工程を省略することが可能でシンプルな工程となりコストの低減に役立ち、効率の良いニッケル粉の製造方法である。 In the conventional process of adding a seed crystal to promote the reaction, a process for manufacturing the seed crystal is separately required, which is expensive.
In contrast to the above-described production method using seed crystals, the method of the present invention uses a polyacrylic acid as a dispersing agent in the form of a polyacrylic acid solution or a polyacrylate, and adds a predetermined amount thereof to a nickel complex solution to produce hydrogen. It has been found that fine nickel powder that has been reduced by hydrogen gas and precipitated in a solution by blowing gas can be used as a seed crystal. Therefore, the present invention is a simple method that can omit the step of producing the seed crystal, is simple and helps to reduce the cost, and is an efficient nickel powder production method.

本発明は、硫酸アンモニウムを含む硫酸ニッケルアンミン錯体溶液に分散剤を加えて形成した分散剤入り混合溶液を加圧容器である反応容器内に連続供給し、反応容器内に吹き込まれている水素ガスと接触させることで、水素による還元力を用いて溶液中から種晶として働くニッケル粉を製造し、引き続きそのニッケル粉をさらに成長させて加圧容器から連続して排出することを特徴とする。
以下、本発明のニッケル粉の製造方法を説明する。 The present invention continuously supplies a mixed solution containing a dispersant formed by adding a dispersant to a nickel sulfate ammine complex solution containing ammonium sulfate into a pressure vessel, and hydrogen gas blown into the reaction vessel. By making contact, nickel powder that acts as a seed crystal is produced from the solution using the reducing power of hydrogen, and the nickel powder is further grown and continuously discharged from the pressurized container.
Hereafter, the manufacturing method of the nickel powder of this invention is demonstrated.

本発明に用いる硫酸ニッケルアンミン錯体溶液は、特に限定はされないが、ニッケルおよびコバルト混合硫化物、粗硫酸ニッケル、酸化ニッケル、水酸化ニッケル、炭酸ニッケル、ニッケル粉などから選ばれる一種、または複数の混合物から成る工業中間物などのニッケル含有物を、硫酸あるいはアンモニアにより溶解して得られるニッケル浸出液（ニッケルを含む溶液）を、溶媒抽出法、イオン交換法、中和などの浄液工程を施すことにより溶液中の不純物元素を除去して得られる溶液に、アンモニアを添加し、硫酸ニッケルアンミン錯体溶液としたもの等が適している。
さらに、硫酸アンモニウムが含まれ、その硫酸アンモニウム濃度は、１０〜５００ｇ／Ｌの範囲とすることが好ましい。５００ｇ／Ｌを超える濃度では溶解度を超えてしまい結晶が析出する。また、反応により硫酸アンモニウムが新たに生成されるため、１０ｇ／Ｌ未満を達成するのは困難である。 The nickel sulfate ammine complex solution used in the present invention is not particularly limited, but one or a mixture selected from nickel and cobalt mixed sulfide, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, nickel powder and the like. By subjecting nickel-containing materials, such as industrial intermediates, to nickel leaching solution (solution containing nickel) obtained by dissolving with sulfuric acid or ammonia, and subjecting it to liquid purification processes such as solvent extraction, ion exchange, and neutralization. A solution obtained by adding ammonia to a solution obtained by removing impurity elements from the solution to form a nickel sulfate ammine complex solution is suitable.
Further, ammonium sulfate is contained, and the ammonium sulfate concentration is preferably in the range of 10 to 500 g / L. If the concentration exceeds 500 g / L, the solubility is exceeded and crystals are deposited. Moreover, since ammonium sulfate is newly produced | generated by reaction, it is difficult to achieve less than 10 g / L.

本発明では、そのような硫酸ニッケルアンミン錯体溶液に、水素ガスで還元されて析出したニッケル粉末を錯体溶液中に分散させるために、分散剤を添加している。その分散剤は、ポリアクリル酸や、液中でポリアクリル酸源となるポリアクリル酸塩であれば特に限定されないが、工業的に安価に入手できるものとしてポリアクリル酸ナトリウムが好適である。   In the present invention, a dispersant is added to such a nickel sulfate ammine complex solution in order to disperse the nickel powder that has been reduced by hydrogen gas and deposited in the complex solution. The dispersing agent is not particularly limited as long as it is polyacrylic acid or a polyacrylic acid salt that becomes a polyacrylic acid source in the liquid, but sodium polyacrylate is suitable as an industrially available material.

分散剤の添加量は、添加するポリアクリル酸やその塩は、硫酸ニッケルアンミン錯体溶液の液量に対してポリアクリル酸が０．０１ｇ／Ｌ以上で１０ｇ／Ｌ以下の濃度になるように添加する。
ポリアクリル酸の濃度が０．０１ｇ／Ｌ未満だと分散剤が少なすぎて適度な粒径のニッケル粉の種晶を得ることができず、その結果不均一なニッケル粉の生成や、ニッケルの還元率（反応率）が低下するので適さない。一方、ポリアクリル酸濃度が１０ｇ／Ｌを超えても効果はなく過剰な添加となる。 The amount of dispersant added is such that the polyacrylic acid and its salt are added in a concentration of 0.01 g / L to 10 g / L with respect to the amount of nickel sulfate ammine complex solution. To do.
If the concentration of polyacrylic acid is less than 0.01 g / L, the amount of the dispersant is too small to obtain a seed crystal of nickel powder having an appropriate particle size. Since the reduction rate (reaction rate) decreases, it is not suitable. On the other hand, even if the polyacrylic acid concentration exceeds 10 g / L, there is no effect and excessive addition occurs.

次に上記分散剤を、硫酸アンモニウムを含む硫酸ニッケルアンミン錯体溶液に添加して形成した分散剤入り混合溶液を、反応容器として、水素ガスによる内圧制御が成されるオートクレーブなどの耐高圧高温容器の反応槽内に連続装入し、反応槽内に分散剤入り混合溶液が占有する液相部と気相部を形成する。   Next, reaction of a high-pressure and high-pressure vessel such as an autoclave in which internal pressure is controlled by hydrogen gas is performed using a mixed solution containing a dispersant formed by adding the dispersant to a nickel sulfate ammine complex solution containing ammonium sulfate as a reaction vessel. The tank is continuously charged, and a liquid phase part and a gas phase part occupied by the mixed solution containing the dispersant are formed in the reaction tank.

その後、連続的に装入状態にある反応槽内の分散剤入り混合溶液は、吹き込まれた内圧制御が施された水素ガスによって、硫酸ニッケルアンミン錯体溶液に含まれていたニッケル錯イオンが還元され、析出した微小な結晶を種としてその上にさらにニッケルを析出させ、成長したニッケル粉を得て、連続的に排出される。   After that, in the mixed solution containing the dispersant in the reaction vessel continuously charged, the nickel complex ions contained in the nickel sulfate ammine complex solution are reduced by the blown-in hydrogen gas whose internal pressure is controlled. Then, using the deposited fine crystals as seeds, nickel is further deposited thereon to obtain a grown nickel powder, which is continuously discharged.

また、本発明では、水素ガスを吹き込んでニッケル錯イオンを還元する還元処理における反応時間が、５分から１２０分の間で維持されるように、分散剤入り混合溶液の反応容器内への供給量と反応容器の外への排出量が調整される。
その時間が５分よりも短い反応時間では、還元反応がほとんど進行せず、ニッケル粉を得ることができない。一方で１２０分を超えるような長時間の還元反応に付しても変化はなく、滞留する液量が増えるため装置が大型になり好ましくない。
このように、本発明では連続処理で還元が行われるために、上記の範囲に反応時間を維持することで、ニッケル粉の成長を安定して制御できる。 Further, in the present invention, the supply amount of the mixed solution containing the dispersing agent into the reaction vessel so that the reaction time in the reduction treatment in which hydrogen gas is blown to reduce the nickel complex ions is maintained between 5 minutes and 120 minutes. And the amount of discharge to the outside of the reaction vessel is adjusted.
When the reaction time is shorter than 5 minutes, the reduction reaction hardly proceeds and nickel powder cannot be obtained. On the other hand, even if it is subjected to a reduction reaction for a long time exceeding 120 minutes, there is no change, and the amount of the remaining liquid increases, which is not preferable because the apparatus becomes large.
Thus, in the present invention, since the reduction is performed by continuous treatment, the growth of nickel powder can be stably controlled by maintaining the reaction time within the above range.

また、このときの反応温度は、１５０℃以上、１８５℃以下の範囲が好ましい。１５０℃未満では還元効率が低下し、１８５℃を超える温度にしても反応への影響はなく、むしろ熱エネルギー等のロスが増加するので適さない。   Moreover, the reaction temperature at this time has the preferable range of 150 degreeC or more and 185 degrees C or less. If it is less than 150 degreeC, reduction efficiency will fall, and even if it exceeds 185 degreeC, there is no influence on reaction, rather, since loss, such as a heat energy, increases, it is not suitable.

さらに、反応時の反応槽の気相部の圧力は２．５〜３．５ＭＰａの範囲に維持することが好ましい。２．５ＭＰａ未満では反応効率が低下し、３．５ＭＰａを超えても反応への影響はなく、水素ガスのロスが増加する。
上記の条件によるニッケルの析出を伴う還元処理によって、吹き込まれた水素ガス自体によって種結晶として使えるニッケル粉を製造し、その種を中心に成長したニッケル粉が得られる。 Furthermore, it is preferable to maintain the pressure in the gas phase part of the reaction tank during the reaction in the range of 2.5 to 3.5 MPa. If it is less than 2.5 MPa, the reaction efficiency decreases, and if it exceeds 3.5 MPa, there is no influence on the reaction, and the loss of hydrogen gas increases.
By the reduction treatment accompanied by precipitation of nickel under the above conditions, nickel powder that can be used as a seed crystal is produced by the blown-in hydrogen gas itself, and nickel powder that grows around the seed is obtained.

以上のようにして製造したニッケル粉は、例えば積層セラミックコンデンサーの内部構成物質であるニッケルペーストの用途として用いることができる他、上記水素還元を繰り返すことにより粒子を成長させ、高純度で取扱いに適した均一なニッケルブリケットなどのメタルを製造することができる。   The nickel powder produced as described above can be used, for example, as a nickel paste, which is an internal constituent material of a multilayer ceramic capacitor. In addition, the particles are grown by repeating the above hydrogen reduction, and high purity and suitable for handling. Metal such as uniform nickel briquette can be produced.

以下、実施例を用いて本発明をさらに説明する。   The present invention will be further described below using examples.

容量が３Ｌの加圧容器（オートクレーブ）に、硫酸アンモニウム濃度で２００ｇ／Ｌ、ニッケルアンミン錯体溶液がニッケル濃度で５５ｇ／Ｌに相当する量、さらにポリアクリル酸濃度が５ｇ／Ｌの割合となる量のポリアクリル酸ナトリウムを混合した分散剤入り混合溶液１Ｌを張り込み、温度１８５℃に保ち、水素ガスを加圧容器の内部圧力（気相部の圧力）が３．５ＭＰａを維持するように吹き込みを始めた。同時に上記と同組成の液を毎分１６．７ｍｌの割合で給液し、同量の液が加圧容器から排出されるようにした。つまり加圧容器内での反応時間は１時間となる。   In a pressure vessel (autoclave) with a capacity of 3 L, an amount corresponding to an ammonium sulfate concentration of 200 g / L, a nickel ammine complex solution corresponding to a nickel concentration of 55 g / L, and a polyacrylic acid concentration of 5 g / L 1 L of a mixed solution containing a dispersant mixed with sodium polyacrylate was put in, and the temperature was maintained at 185 ° C., and hydrogen gas was started to be blown so that the internal pressure of the pressurized container (pressure in the gas phase) was maintained at 3.5 MPa. It was. At the same time, a liquid having the same composition as above was supplied at a rate of 16.7 ml per minute so that the same amount of liquid was discharged from the pressurized container. That is, the reaction time in the pressurized container is 1 hour.

供給した水素ガス量が理論的に還元できるニッケル量に対して実際に還元されたニッケル量の割合をニッケルの反応率と定義すると、ニッケルの反応率は９５％となり、効率の良い反応が達成された。
得られた粒子の産出粒子径は、累積分布５０％の粒径であるＤ５０（メジアン径）で表わすと１４μｍとなり、配管を閉塞するなどの問題はなかった。 If the ratio of the amount of nickel actually reduced to the amount of nickel that can be theoretically reduced by the amount of hydrogen gas supplied is defined as the nickel reaction rate, the nickel reaction rate is 95%, and an efficient reaction is achieved. It was.
The produced particle diameter of the obtained particles was 14 μm when expressed by D50 (median diameter), which is the particle diameter of 50% cumulative distribution, and there was no problem of blocking the pipe.

（比較例１）
上記実施例１と同じ加圧容器にポリアクリル酸を含まない以外は実施例１と同組成の混合溶液を毎分１６．７ｍｌの流量で供給、排出した。 (Comparative Example 1)
A mixed solution having the same composition as in Example 1 was supplied and discharged at a flow rate of 16.7 ml per minute, except that the same pressurized container as in Example 1 did not contain polyacrylic acid.

ニッケルの反応率は３８％にとどまり、得られた粒子の産出粒子径はＤ５０で６８μｍと過剰に粗大なものだった。   The reaction rate of nickel was only 38%, and the output particle diameter of the obtained particles was excessively coarse with a D50 of 68 μm.

以上の結果を纏めて表１に示す。
表１に示すように、本発明の方法を用いることで、高い反応効率でニッケル粉を安定かつ連続して製造できることを確認した。 The above results are summarized in Table 1.
As shown in Table 1, it was confirmed that nickel powder could be produced stably and continuously with high reaction efficiency by using the method of the present invention.

Claims (3)

硫酸アンモニウムを含む硫酸ニッケルアンミン錯体溶液に、前記硫酸ニッケルアンミン錯体溶液に対して０．０１ｇ／Ｌ以上、１０ｇ／Ｌ以下の濃度となる量のポリアクリル酸を分散剤として含有した分散剤入り混合溶液を作製し、
次いで前記分散剤入り混合溶液を、反応容器内に供給し、前記反応容器内に吹き込まれていた水素ガスに連続的に接触させ、前記硫酸ニッケルアンミン錯体溶液中のニッケル錯イオンを還元処理してニッケル粉を生成した後、得られたニッケル粉を含むスラリーを、前記反応容器の外に排出することを特徴とするニッケル粉の製造方法。 A mixed solution containing a dispersant containing, in a nickel sulfate ammine complex solution containing ammonium sulfate, polyacrylic acid in an amount of 0.01 g / L or more and 10 g / L or less with respect to the nickel sulfate ammine complex solution as a dispersant. Make
Next, the mixed solution containing the dispersant is supplied into a reaction vessel, and continuously contacted with the hydrogen gas blown into the reaction vessel to reduce the nickel complex ions in the nickel sulfate ammine complex solution. After producing | generating nickel powder, the slurry containing the obtained nickel powder is discharged | emitted out of the said reaction container, The manufacturing method of the nickel powder characterized by the above-mentioned. 前記還元処理における前記硫酸ニッケルアンミン錯体溶液を水素ガスに接触させる時間が、５分から１２０分間になるように、前記反応容器内に水素ガスを吹き込むと共に、前記分散剤入り混合溶液を前記反応容器内に供給し前記反応容器の外に排出することを特徴とする請求項１に記載のニッケル粉の製造方法。   Hydrogen gas is blown into the reaction vessel so that the time during which the nickel sulfate ammine complex solution is brought into contact with hydrogen gas in the reduction treatment is 5 minutes to 120 minutes, and the mixed solution containing the dispersant is placed in the reaction vessel. The nickel powder production method according to claim 1, wherein the nickel powder is supplied to the reactor and discharged out of the reaction vessel. 前記還元処理が、２．５〜３．５ＭＰａの範囲の圧力下で、１５０〜１８５℃の温度範囲に維持されて行われることを特徴とする請求項１又は２に記載のニッケル粉の製造方法。   The method for producing nickel powder according to claim 1 or 2, wherein the reduction treatment is performed while maintaining a temperature range of 150 to 185 ° C under a pressure in a range of 2.5 to 3.5 MPa. .