JP6531913B2 - Method of producing nickel powder - Google Patents

Description

The present invention relates to a method for obtaining high purity nickel powder and briquettes obtained by solidifying it from a nickel sulfate ammonium complex solution.
In particular, it can be applied to the treatment of an intermediate product solution in the process generated in the wet nickel smelting process.

  As a method of industrially producing nickel powder using a hydrometallurgical process, after dissolving the raw materials in sulfuric acid solution and removing impurities, ammonia is added to the obtained nickel sulfate solution to obtain an ammine complex of nickel There is a method of producing a nickel powder by supplying hydrogen gas to the solution of nickel ammonium sulfate complex formed and reducing the nickel.

  For example, Non-Patent Document 1 describes a production process of a nickel powder in which an iron compound is added as seed crystals during reduction reaction to precipitate nickel on the iron compound, but iron contamination derived from seed crystals in the product One point is the problem.

Furthermore, methods for obtaining nickel powder using reducing agents other than hydrogen gas have also been proposed.
For example, Patent Document 1 is inexpensive and excellent in weather resistance, has low electric resistance in the state of being kneaded with a resin, reduces initial electric resistance and electric resistance during use, and can be used stably for a long period of time, conductive Disclosed are nickel powders suitable as conductive particles for pastes and conductive resins, and methods of providing the same.

  The nickel powder disclosed in Patent Document 1 is a nickel powder containing 1 to 20 mass% of cobalt, the balance being nickel and an unavoidable impurity, and being composed of secondary particles in which primary particles are aggregated, The amount is 0.8% by mass or less. It is said that it is preferable that cobalt be contained only in the surface layer portion of the secondary particles, and the cobalt content in the surface layer portion be 1 to 40% by mass.

  When it is intended to obtain this nickel powder according to the disclosed manufacturing method, cobalt will co-exist, and nickel and cobalt co-exist as in, for example, nickel oxide ore, and these are separated and separated. It is not suitable for high purity and economical recovery applications.

Further, Patent Document 2 provides a method of producing a metal powder by a liquid phase reduction method, which is improved so as not to easily generate particle aggregates.
This manufacturing method is carried out by dissolving the metal compound, the reducing agent, the complexing agent, and the dispersing agent to thereby adjust the pH of the aqueous solution by the first step of preparing an aqueous solution containing metal ions derived from the metal compound. And a second step of depositing metal powder by reducing metal ions with a reducing agent.
However, this production method is expensive using expensive chemicals, and it is not economically advantageous to apply to the above-mentioned large scale operation as nickel smelting.

  As described above, various processes for producing nickel powder have been proposed, but a method for producing high purity nickel powder using industrially inexpensive hydrogen gas has not been proposed.

JP, 2005-240164, A JP, 2010-242143, A

POWDER METALLURGY, 1958, no. 1/2, P. 40-52

  Under such circumstances, it is possible to provide a manufacturing method for producing coarse particles of high purity nickel powder from a nickel sulfate ammonium complex solution using industrially inexpensive hydrogen gas and using fine nickel powder. It is the purpose.

The first invention of the present invention for solving such problems is a process for producing nickel powder from a nickel sulfate ammonium complex solution, wherein (1) the nickel ammonium sulfate complex solution has an average particle diameter of 0.1 to 5 μm. A seed crystal addition step of forming a mixed slurry by adding nickel powder as a seed crystal.
(2) Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the treatment step (1), and the nickel component in the mixed slurry is precipitated including the nickel powder formed by precipitation on the seed crystals. Reduction process to form a slurry.
(3) The reduced slurry obtained in the reduction step of the treatment step (2) is solid-liquid separated to separate and recover the nickel powder as a solid phase component, and then nickel hydroxide is added to the recovered nickel powder. Hydrogen gas is blown into a solution to which a solution of nickel sulfate ammonium complex obtained by dissolving in a solution after reaction obtained from the reduction step is added to form a growth slurry containing high purity nickel powder obtained by growing the nickel powder. It is a manufacturing method of the nickel powder characterized by performing the treatment process shown to (1)-(3) of a process.

  In the second invention of the present invention, when the seed crystals in the seed crystal addition step of the treatment step (1) in the first invention are added to the nickel sulfate ammonium complex solution to form a mixed slurry, the dispersant is added to the mixed slurry Is further added, and it is a manufacturing method of nickel powder characterized by the above-mentioned.

  According to a third aspect of the present invention, the amount of seed crystals added in the seed crystal addition step of the processing step (1) of the first and second aspects is 1 with respect to the weight of nickel in the nickel sulfate ammonium complex solution. The method is a method for producing nickel powder, which is characterized in that the amount is about 100%.

  According to a fourth aspect of the present invention, there is provided a leaching process in which the nickel sulfate ammonium complex solution according to any of the first to third inventions dissolves a nickel-containing substance containing cobalt as an impurity, and nickel and cobalt obtained in the leaching process. The pH of the leaching solution is adjusted, and then a solvent extraction step of separating into a nickel sulfate solution and a cobalt recovery solution by a solvent extraction method, and a nickel sulfate obtained through a complexing step of complexing the obtained nickel sulfate solution with ammonia It is an ammine complex solution and it is a manufacturing method of nickel powder characterized by the above-mentioned.

  According to a fifth aspect of the present invention, the nickel-containing material in the fourth aspect is at least one of a mixed sulfide of nickel and cobalt, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, and metallic nickel powder. It is a manufacturing method of the nickel powder characterized by a certain thing.

According to a sixth aspect of the present invention, the organic phase of the solvent extraction method in the fourth and fifth aspects is 2-ethylhexylphosphonic acid mono 2-ethylhexyl ester or di- (2,4,4-trimethylpentyl) phosphinic acid It is a manufacturing method of nickel powder characterized by being.

In a seventh invention of the present invention, the ammonium sulfate concentration in the nickel sulfate ammonium complex solution in the fourth to sixth inventions is 100 to 500 g / L, and the ammonium concentration is molar relative to the nickel concentration in the complex solution. It is a manufacturing method of nickel powder characterized by being 1.9 or more in ratio.

In the eighth invention of the present invention, the reduction step of the treatment step (2) and the growth step of the treatment step (3) in the first invention have a temperature of 150 to 200 ° C. and a pressure of 1.0 to 4. It is a manufacturing method of nickel powder characterized by performing each processing maintaining in the range of 0MPa.

The ninth invention of the present invention is the method for producing a nickel powder, wherein the dispersant in the second invention contains an acrylate or a sulfonic acid.

The tenth invention of the present invention relates to a nickel powder ore which processes high purity nickel powder obtained through the growth step of the treatment step (3) in the first invention into massive nickel briquettes using a briquette machine. Including a briquette sintering step of sintering the obtained massive nickel briquette in a hydrogen atmosphere under holding conditions at a temperature of 500 to 1200 ° C. to form a nickel briquette of a sintered body It is a manufacturing method of the nickel powder which is characterized.

The eleventh invention of the present invention is the solid-liquid separation treatment of the reduction slurry obtained in the reduction process of the treatment process (2) in the first invention and the growth slurry obtained in the growth process of the treatment process (3). It is a method for producing a nickel powder comprising an ammonium sulfate recovery step of concentrating a solution after reaction after separating nickel powder as a solid phase component and crystallizing ammonium sulfate to recover ammonium sulfate crystals.

A twelfth invention of the present invention is the solid-liquid separation treatment of the reduction slurry obtained in the reduction step of the treatment step (2) in the first invention and the growth slurry obtained in the growth step of the treatment step (3). An alkali is added to the solution after reaction after separating nickel powder as a solid phase component, and the solution is heated to volatilize ammonia gas for recovery to recover ammonia powder.

According to a thirteenth invention of the present invention, the ammonia recovered in the ammonia recovery step in the twelfth invention is pH adjustment of the solvent extraction step described in the fourth invention, and formation of a nickel sulfate ammonium complex solution in the complexing step. It is a method for producing nickel powder, which is characterized by being recycled to ammonia used.

The fourteenth invention of the present invention is characterized in that the sodium polyacrylate aqueous solution is added at 2.0 wt% relative to the amount of seed crystals to the dispersant in the reduction step of the treatment step (2) of the second invention. It is a manufacturing method of nickel powder.

  According to the present invention, in a method of producing nickel powder from a nickel sulfate ammonium complex solution using hydrogen gas, high purity nickel powder can be easily obtained by using seed crystals that do not contaminate the product. Can.

It is a manufacture flow figure of the nickel powder of the present invention. It is a result of the bulk density and particle size of nickel powder when repetitive reduction is performed using acrylate or sulfonate as a dispersant. It is a nickel powder SEM image after performing reduction using an acrylate or a sulfonate as a dispersing agent in Example 4 of this application.

  In the present invention, in the production method for obtaining nickel powder from a nickel sulfate ammonium complex solution, the steps shown in the following (1) to (3) are applied to the process liquid of the wet smelting process to obtain more nickel sulfate from the nickel sulfate ammonium complex solution It is characterized in that high purity nickel powder with few impurities is produced.

  Hereinafter, the method for producing high purity nickel powder of the present invention will be described with reference to the production flow chart of the high purity nickel powder of the present invention shown in FIG.

[Leaching process]
First, the leaching step is an industrial intermediate or the like consisting of one or a mixture of nickel and cobalt mixed sulfide, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, nickel powder, etc., as a starting material. The step of dissolving the nickel-containing material with sulfuric acid and leaching the nickel to form a leaching solution (a solution containing nickel), which is performed using a known method disclosed in JP-A-2005-350766 and the like. .

[Solvent extraction process]
Next, the pH of the leachate is adjusted and subjected to a solvent extraction step.
This step is carried out by bringing the pH-adjusted leachate into contact with the organic phase after exchange from the leaching step, and exchanging the components in each phase to increase the concentration of one component in the aqueous phase and the other different components. Lower the concentration of

  In the present invention, 2-ethylhexylphosphonic acid mono 2-ethylhexyl ester or di- (2,4,4-trimethylpentyl) phosphinic acid is used in the organic phase to selectively extract impurity elements in the leachate, especially cobalt, It is intended to obtain a nickel sulfate solution of purity.

  Moreover, the ammonia water produced | generated by the ammonia collection process mentioned later can be used for the ammonia water used for pH adjustment at this process.

[Complexing process]
In this complexing step, ammonia of ammonia gas or ammonia water is added to the high purity nickel sulfate solution obtained in the solvent extraction step, complexing treatment is performed to form a nickel sulfate ammonium complex which is an ammonium complex of nickel, It is the process of forming the nickel sulfate ammonium complex solution.
Ammonia is added so that the ammonium concentration at this time is 1.9 or more in molar ratio with respect to the nickel concentration in the solution. When the ammonium concentration of ammonia to be added is less than 1.9, nickel does not form an ammine complex, and a nickel hydroxide precipitate is formed.

In addition, ammonium sulfate can be added in this step to adjust the ammonium sulfate concentration. The ammonium sulfate concentration at this time is preferably 100 to 500 g / L, and if it is 500 g / L or more, the solubility will be exceeded and crystals will precipitate, making it difficult to achieve less than 100 g / L in terms of metal balance of the process. .
Furthermore, the ammonia gas or ammonia water produced | generated by the ammonia collection | recovery process mentioned later can also be used for the ammonia gas or ammonia water used at this process.

  Furthermore, using nickel hydroxide containing nickel, the reduced slurry obtained in the (2) reduction step is subjected to solid-liquid separation treatment to dissolve nickel hydroxide in the reaction solution, thereby dissolving nickel hydroxide in the reaction solution. It is possible to react with ammonium sulfate to form a nickel sulfate ammonium complex solution. Ammonium sulfate remains in the post-reaction solution used during the production process. Further, when the ammonium concentration or the ammonium sulfate concentration does not reach the above-mentioned appropriate range, an appropriate amount of ammonia or ammonium sulfate may be replenished.

[Manufacturing process of nickel powder from nickel sulfate ammonium complex solution]
The process of producing a nickel powder from the nickel sulfate ammonium complex solution shown in the process steps (1) to (3) surrounded by the broken line in FIG. 1 will be described below. The bold arrows in the figure indicate the process flow in this process.

(1) Seed Crystal Addition Step To the nickel sulfate ammonium salt complex solution obtained in the above complexing step, nickel powder is added in the form of a nickel powder slurry using nickel powder having an average particle diameter of 0.1 to 5 μm as seed crystals. A mixed slurry is formed. In addition, it is possible to produce this nickel powder made into a seed crystal by the below-mentioned "seed crystal production process."
The weight of the seed crystals added at this time is preferably 1 to 100% with respect to the weight of nickel in the nickel sulfate ammonium complex solution. If it is less than 1%, the reaction efficiency at the time of reduction in the next step is significantly reduced. Further, if it is 100% or more, the amount used is large, the cost of producing seed crystals is high and it is not economical.

Moreover, you may add a dispersing agent simultaneously. Since the seed crystals are dispersed by adding this dispersant, the efficiency of the reduction step in the next step can be increased.
The dispersant to be used here is not particularly limited as long as it has an acrylate or sulfonate, but polyacrylate is preferred as one which can be obtained at low cost industrially.

(2) Reduction step Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the treatment step (1) to deposit nickel in the solution on the seed crystals, thereby depositing on the seed crystals. To form a reducing slurry containing the nickel powder formed.
At this time, the reaction temperature is preferably 150 to 200 ° C. If the temperature is less than 150 ° C., the reduction efficiency decreases, and if the temperature exceeds 200 ° C., the reaction is not affected, and the loss of heat energy and the like increases.
Moreover, the pressure at the time of reaction is preferably 1.0 to 4.0 MPa. If the pressure is less than 1.0 MPa, the reaction efficiency decreases, and if the pressure exceeds 4.0 MPa, the reaction is not affected, and the loss of hydrogen gas increases.

  Although magnesium ion, sodium ion, sulfate ion and ammonium ion are mainly present as impurities in the mixed slurry liquid obtained in the seed crystal addition step of treatment step (1), all of them remain in the solution. And high purity nickel powder can be produced.

(3) Growth step After solid-liquid separation of the reduced slurry generated in the reduction step of the treatment step (2), the nickel sulfate ammonium complex solution obtained in the above-mentioned complexing step is added to the recovered high purity nickel powder. A grain growth process of supplying hydrogen gas is performed by the same method as the reduction process of (2) to form a growth slurry containing grain-grown nickel powder. Thereby, since nickel is reductively precipitated on the high purity nickel powder, particles can be grown.

Further, by repeating the present growth step a plurality of times, it is possible to produce high purity nickel powder having a higher bulk density and a larger particle size.
In addition, the obtained nickel powder may be finished into the shape of a briquette that is coarser, less likely to be oxidized, and easy to handle through the following nickel powder massing process and briquette firing process.
Furthermore, an ammonia recovery step may be provided.

Prior to the seed crystal addition step, a “seed crystal generation step” may be performed as a step of producing a seed crystal to be used, and the outline thereof will be described below.
This step is a step of mixing a high purity nickel sulfate solution obtained in the solvent extraction step with hydrazine to produce fine nickel powder as seed crystals.
At this time, an alkali may be further mixed, and it is preferable to add ammonia as the alkali to be used at a molar ratio of 2 times or more with respect to the amount of nickel in the nickel sulfate solution and adjust the pH to 7 to 12 using caustic soda.

The addition amount of hydrazine to be used is preferably 0.5 to 2.5 times by molar ratio to the amount of nickel in nickel sulfate. If it is less than 0.5 times, the nickel does not react in all, and if it exceeds 2.5 times, the reaction efficiency is not affected and the drug loss increases.
Moreover, 25-80 degreeC of reaction temperature is preferable, and when it is less than 25 degreeC, reaction time will become long, and it is not realistic for industrial application. On the other hand, at 80 ° C. or higher, the equipment cost is high because the material of the reaction tank is limited. Furthermore, the particle size of the nickel powder produced can be made finer by adding a small amount of surfactant at this time.
The fine nickel powder having an average particle diameter of 0.1 to 5 μm, which is the seed crystals generated in this manner, is solid-liquid separated and supplied as a slurry-like nickel powder slurry.

[Nickel powder group mining process]
The high purity nickel powder produced according to the present invention is, after being dried, formed and processed by means of a ball mill or the like as a product form to obtain massive nickel briquettes.
Moreover, in order to improve the formability to this briquette, in some cases, a substance that does not contaminate the product quality, such as water, is added to the nickel powder as a binder.

[Briquette sintering process]
The nickel briquettes produced in the briquette process are roasted and sintered in a hydrogen atmosphere to produce briquettes. In this treatment, the strength is increased and the residual ammonia and sulfur components are removed, and the roasting / sintering temperature is preferably 500 to 1200 ° C. If it is less than 500 ° C., sintering is insufficient, and even if it exceeds 1200 ° C., the efficiency hardly changes and the energy loss increases.

[Ammonium sulfate recovery process]
Ammonium sulfate and ammonia are contained in the liquid after reaction generated by solid-liquid separation processing in which each slurry in the reduction step of the treatment step (2) and the growth step of the treatment step (3) is separated with nickel powder as a solid phase.
Thus, ammonium sulfate can be recovered as ammonium sulfate crystals by crystallizing ammonium sulfate by heating and concentrating the solution after reaction by performing an ammonium sulfate recovery step.

[Ammonia recovery process]
In addition, ammonia can be recovered by volatilizing the ammonia gas by heating after adding an alkali to the reaction solution to adjust the pH to 10-13.
Although the alkali used here is not particularly limited, caustic soda, slaked lime, etc. are preferable because they are industrially inexpensive.
The recovered ammonia gas can be brought into contact with water to produce ammonia water, and the obtained ammonia water can be repeatedly used in the process.

  Hereinafter, the present invention will be described in more detail using examples.

[Formation of seed crystals]
36 g of sodium hydroxide and 53 ml of a 60% hydrazine solution were added to 73 ml of 25% ammonia water, and the total volume was adjusted to 269 ml.
Using a water bath, 273 g of a nickel sulfate solution (100 g / L) was added dropwise to the solution in the beaker and reacted while maintaining the solution temperature at 75 ° C. and stirring, and the solution was maintained for 30 minutes. Thereafter, solid-liquid separation was performed, and the produced nickel powder was recovered. The average particle size of the obtained nickel powder was 2 μm.

(1) Seed Crystal Addition Step To a solution containing nickel sulfate solution containing 75 g of nickel and 330 g of ammonium sulfate, 191 ml of 25% ammonia water was added to adjust the total liquid volume to 1000 ml. To this solution was added 7.5 g of the nickel powder obtained in the above "seed crystal generation" as a seed crystal to prepare a mixed slurry.

(2) Reduction step The mixed slurry prepared in (1) is heated to 185 ° C. while stirring in an autoclave, and hydrogen gas is blown into the autoclave so that the pressure in the autoclave becomes 3.5 MPa, and supplied and reduced. The nickel powder production process was performed.

  One hour after the supply of hydrogen gas, the supply of hydrogen gas was stopped and the autoclave was cooled. The reduced slurry obtained after cooling was subjected to solid-liquid separation treatment by filtration to recover a high purity small diameter nickel powder. The amount of nickel powder recovered at this time was 70 g.

(3) Growth Step Next, 191 ml of 25% aqueous ammonia was added to a solution containing 336 g of nickel sulfate and 330 g of ammonium sulfate concentration, and the total liquid volume was adjusted to 1000 ml.
A total amount of the high-purity small diameter nickel powder obtained in (2) above was added to this solution to prepare a slurry.

The slurry was heated to 185 ° C. while being stirred by an autoclave, and hydrogen gas was blown into the autoclave so that the pressure in the autoclave was 3.5 MPa.
One hour after the supply of hydrogen gas, the supply of hydrogen gas was stopped and the autoclave was cooled. The growth slurry obtained after cooling was subjected to solid-liquid separation treatment by filtration to recover high-purity grain-grown nickel powder.

  After adding 75 g of nickel powder having an average particle diameter of 1 μm as seed crystals to 1000 ml of the nickel sulfate ammonium complex solution shown in Table 1, the temperature is raised to 185 ° C. while stirring in an autoclave, and the pressure in the autoclave is 3.5 MPa The hydrogen gas was blown and supplied to

  One hour after the supply of hydrogen gas, the supply of hydrogen gas was stopped and the autoclave was cooled. The reduced slurry obtained after cooling was subjected to solid-liquid separation treatment by filtration, and the recovered nickel powder was washed with pure water, and then the impurity grade of the nickel powder was analyzed. The results are shown in Table 1. Mg and Na were not mixed in the nickel powder, and it was possible to produce high purity Ni powder.

  To a solution containing 75 g of seed crystals, 1.5 g of sodium polyacrylate, 336 g of nickel sulfate, and 330 g of ammonium sulfate concentration prepared in the “growth step” of Example 1, 191 ml of 25% ammonia water is added, and the total liquid volume is A mixed slurry adjusted to 1000 ml was prepared.

Next, the mixed slurry was heated to 185 ° C. while being stirred in an autoclave, and hydrogen gas was blown into the autoclave so that the pressure in the autoclave was 3.5 MPa and supplied. One hour after the supply of hydrogen gas, the supply of hydrogen gas was stopped.
After cooling of the autoclave, the obtained reduced slurry was subjected to solid-liquid separation treatment by filtration to recover small-diameter nickel powder. At this time, the nickel concentration in the solution after reaction was 0.4 g / L, and a reduction rate of 99% or more was obtained.

A slurry was prepared by adding 191 ml of 25% ammonia water to a solution containing the small diameter nickel powder, 336 g of nickel sulfate, and 330 g of ammonium sulfate concentration recovered in Example 3 so that the total liquid volume would be 1000 ml.
The temperature is raised to 185 ° C. while stirring in the autoclave again, and hydrogen gas is blown into the autoclave so that the pressure in the autoclave becomes 3.5 MPa, supplied and subjected to grain growth treatment, and then through solid-liquid separation treatment by filtration. The grain-grown nickel powder was recovered.
This operation was repeated to grow more nickel powder.

  As shown in FIG. 2, the nickel powder obtained in Example 4 is growing by repeating the growth step and performing reduction to increase its particle size. In contrast, the bulk density decreases as the number of repeated reductions increases. Further, since the nickel powder generated from the SEM image of FIG. 3 has a particle shape having irregularities on the surface, it is coarser and easier than nickel powder when using lignin sulfonate as the dispersant shown in Comparative Example 3. Soluble nickel powder could be obtained.

The sulfur grade in the obtained nickel powder was 0.04%.
Therefore, this nickel powder was subjected to a roasting treatment of heating to 1000 ° C. and holding for 60 minutes in a 2% hydrogen atmosphere. The sulfur grade in the nickel powder obtained after roasting was 0.008%, and the sulfur grade could be reduced by roasting.

By adding 800 ml of slaked lime adjusted to a slurry concentration of 200 g / L to 1000 ml of a nickel sulfate solution having a nickel concentration of 120 g / L, 120 g of nickel hydroxide was obtained.
The nickel hydroxide is mixed into 1700 ml of a mixed solution of a nickel sulfate solution having a nickel concentration of 30 g / L and an ammonium sulfate solution having an ammonia concentration of 40 g / L, which simulates the post-reaction solution obtained in the reduction step. A slurry was made.

  Next, the slurry is heated to 185 ° C. while stirring in an autoclave, and hydrogen gas is blown into the autoclave so that the pressure in the autoclave becomes 3.5 MPa, and the grain growth processing is performed, and then the solid by filtration is obtained. After liquid separation processing, the grain-grown nickel powder was recovered.

(Comparative example 1)
A solution prepared by mixing 45 ml of pure water, 20 g of nickel sulfate hexahydrate, 15 g of ammonium sulfate and 10 ml of 28% aqueous ammonia without using seed crystals is placed in an autoclave, and hydrogen gas is supplied to 3.5 MPa while stirring. After raising the temperature to 185 ° C., it was held for 6 hours. After cooling, when the inside of the autoclave was checked, the precipitates adhered as scales on the vessel and the stirring blade, and it was not possible to produce powdery nickel.

(Comparative example 2)
The reduction step was carried out in the same manner as in Example 3 except that sodium lignin sulfonate was not added. As a result, 33 g of nickel powder that could be recovered remained at a recovery rate of 14%.

(Comparative example 3)
As a dispersant, 7.5 g of sodium lignin sulfonate was added, and the other conditions were repeated in the same manner as in Example 4 to conduct a growth test.
As a result, as shown in FIG. 2, the particle size of the nickel powder increases as the number of repeated reductions increases. However, the bulk density remained unchanged from about 5 g / cm ³ .

Claims (14)

In a production process for producing nickel powder from a nickel sulfate ammonium complex solution,
The manufacturing method of the nickel powder characterized by performing the process process shown to following (1) to (3).
(1) A seed crystal addition step of forming a mixed slurry by adding a nickel powder having an average particle diameter of 0.1 to 5 μm as a seed crystal to the nickel sulfate ammonium complex solution.
(2) Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the treatment step (1), and the nickel component in the mixed slurry is precipitated including the nickel powder formed by precipitation on the seed crystals. Reduction process to form a slurry.
(3) The reduced slurry obtained in the reduction step of the treatment step (2) is solid-liquid separated to separate and recover the nickel powder as a solid phase component, and then nickel hydroxide is added to the recovered nickel powder. Hydrogen gas is blown into a solution to which a solution of nickel sulfate ammonium complex obtained by dissolving in a solution after reaction obtained from the reduction step is added to form a growth slurry containing high purity nickel powder obtained by growing the nickel powder. Process.   When adding the seed crystals in the seed crystal addition step of the treatment step (1) to the nickel sulfate ammonium complex solution to form a mixed slurry, a dispersant is further added to the mixed slurry. The manufacturing method of the nickel powder as described in 1.   The method is characterized in that the added amount of the seed crystals added in the seed crystal addition step of the treatment step (1) is 1 to 100% with respect to the weight of nickel in the nickel sulfate ammonium complex solution. The manufacturing method of the nickel powder as described in 1 or 2. The nickel ammonium sulfate complex solution is
A leaching step of dissolving a nickel-containing substance containing cobalt as an impurity;
A solvent extraction step of pH-adjusting the leaching solution containing nickel and cobalt obtained in the leaching step, and separating into a nickel sulfate solution and a cobalt recovery solution by a solvent extraction method;
A complexing step of complexing the nickel sulfate solution with ammonia,
It is a nickel sulfate ammonium complex solution obtained by passing through, The manufacturing method of the nickel powder of any one of Claims 1-3 characterized by the above-mentioned.   The nickel according to claim 4, wherein the nickel-containing substance is at least one of a mixed sulfide of nickel and cobalt, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, and metallic nickel powder. How to make powder.   The nickel according to claim 4 or 5, wherein the organic phase in the solvent extraction method is 2-ethylhexylphosphonic acid mono 2-ethylhexyl ester or di- (2,4,4-trimethylpentyl) phosphinic acid. How to make powder. The ammonium sulfate concentration in the nickel sulfate ammonium complex solution is 100 to 500 g / L,
The method for producing a nickel powder according to any one of claims 4 to 6 , wherein the ammonium concentration is 1.9 or more in molar ratio with respect to the nickel concentration in the complex solution.   In the reduction step of the treatment step (2) and the growth step of the treatment step (3), each treatment is performed while maintaining the temperature in the range of 150 to 200 ° C. and the pressure in the range of 1.0 to 4.0 MPa. The manufacturing method of the nickel powder of Claim 1 characterized by the above-mentioned.   The method for producing nickel powder according to claim 2, wherein the dispersant comprises an acrylate or a sulfonic acid. A nickel powder ore process for processing high purity nickel powder obtained through the growth process of the treatment process (3) into massive nickel briquettes using a briquette machine;
The obtained massive nickel briquettes are characterized by including a briquette sintering step of sintering in a hydrogen atmosphere under a holding condition at a temperature of 500 to 1200 ° C. to form nickel briquettes of a sintered body. The manufacturing method of the nickel powder of Claim 1.   After reaction after separation of nickel powder as a solid phase component by solid-liquid separation treatment of the reduced slurry obtained in the reduction step of the treatment step (2) and the growth slurry obtained in the growth step of the treatment step (3) The method for producing a nickel powder according to claim 1, further comprising an ammonium sulfate recovery step of concentrating the liquid and crystallizing ammonium sulfate to recover ammonium sulfate crystals.   After reaction after separation of nickel powder as a solid phase component by solid-liquid separation treatment of the reduced slurry obtained in the reduction step of the treatment step (2) and the growth slurry obtained in the growth step of the treatment step (3) The method for producing a nickel powder according to claim 1, further comprising an ammonia recovery step of adding alkali to the solution and heating to volatilize and recover ammonia gas. Claim ammonia recovered in said ammonia recovery step, wherein the billing pH adjustment of the solvent extraction process of claim 4, and to be recycled to the ammonia used for the production of nickel sulfate ammine complex solution in the complexing step 12 The manufacturing method of the described nickel powder.   The method for producing a nickel powder according to claim 2, wherein 2.0 wt% of an aqueous solution of sodium polyacrylate with respect to the amount of seed crystals is added to the dispersant in the reduction step of the treatment step (2).