JP2017155253A - Production method of nickel powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method to form coarse particles of nickel powder of high-purity from a nickel sulfate ammine complex solution by using an industrially inexpensive hydrogen gas and fine nickel powder.SOLUTION: Provided is a production process of forming nickel powder from a nickel sulfate ammine complex solution, where the following treatment steps (1) to (3) are performed: (1) a seed crystal addition step of adding nickel powder as a seed crystal to a nickel sulfate ammine complex solution to form a mixture slurry; (2) a reduction step of forming a reduced slurry containing nickel powder formed by precipitation of a nickel component in the mixture slurry on seed crystals, by blowing hydrogen gas into the mixture slurry obtained in the seed crystal addition step; and (3) a growth step of performing solid-liquid separation of the reduced slurry obtained in the reduction step to separate and recover nickel powder as a solid phase component and, thereafter, blowing hydrogen gas into a solution obtained by adding a nickel sulfate ammine complex solution to the nickel powder to form a grown slurry containing high purity nickel powder obtained by making nickel powder grow.SELECTED DRAWING: None

Description

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

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

  For example, Non-Patent Document 1 describes a manufacturing process of nickel powder in which an iron compound is added as a seed crystal during a reduction reaction, and nickel is deposited on the iron compound. A certain point is a problem.

Furthermore, methods for obtaining nickel powder using a reducing agent other than hydrogen gas have been proposed.
For example, Patent Document 1 is inexpensive and excellent in weather resistance, has low electrical resistance in a kneaded state with a resin, reduces initial electrical resistance and electrical resistance during use, and can be used stably over a long period of time. A nickel powder suitable as conductive particles for a paste and a conductive resin, and a method for providing a method for producing the same are disclosed.

  The nickel powder disclosed in Patent Document 1 is a nickel powder containing secondary particles in which cobalt is contained in an amount of 1 to 20% by mass, the balance is made of nickel and inevitable impurities, and primary particles are aggregated, and contains oxygen. The amount is 0.8% by mass or less. Cobalt is contained only in the surface layer portion of the secondary particles, and the cobalt content in the surface layer portion is preferably 1 to 40% by mass.

  When this nickel powder is obtained by the disclosed manufacturing method, cobalt coexists. For example, nickel and cobalt coexist like nickel oxide ore. It is not suitable for high purity and economical recovery applications.

Furthermore, Patent Document 2 provides a method for producing metal powder by a liquid phase reduction method, which is improved so as not to easily generate particle aggregates.
In this production method, by dissolving a metal compound, a reducing agent, a complexing agent, and a dispersant, a first step of preparing an aqueous solution containing metal ions derived from the metal compound, and adjusting the pH of the aqueous solution And a second step of reducing metal ions with a reducing agent and precipitating the metal powder.
However, this production method is expensive using an expensive chemical and is not economically advantageous when applied to a process that operates on a large scale as the nickel smelting.

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

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

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

  Under such circumstances, use of industrially inexpensive hydrogen gas and provision of a production method for producing coarse particles of high-purity nickel powder from a nickel sulfate ammine complex solution using fine nickel powder It is the purpose.

A first invention of the present invention for solving such problems is a manufacturing process for producing nickel powder from a nickel sulfate ammine complex solution. (1) The nickel sulfate ammine complex solution has an average particle size of 0.1 to 5 μm. A seed crystal addition step of adding a nickel powder as a seed crystal to form a mixed slurry.
(2) Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the processing step (1), and the nickel component in the mixed slurry is reduced to include nickel powder formed by precipitation on the seed crystal. A reduction process for forming 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 the recovered nickel powder is mixed with a nickel sulfate ammine complex solution. (1) to (3) of a growth process for forming a growth slurry containing high purity nickel powder in which hydrogen gas is blown into a solution to which nickel powder has been grown and nickel powder is formed. It is a manufacturing method of powder.

  In the second invention of the present invention, when the seed crystal in the seed crystal addition step of the processing step (1) in the first invention is added to the nickel sulfate ammine complex solution to form a mixed slurry, a dispersant is added to the mixed slurry. Is a method for producing nickel powder, characterized by further adding.

  In the third invention 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 inventions is 1 with respect to the weight of nickel in the nickel sulfate ammine complex solution. It is the amount which will be -100%, It is a manufacturing method of the nickel powder characterized by the above-mentioned.

  According to a fourth aspect of the present invention, the nickel sulfate ammine complex solution according to the first to third aspects comprises a leaching step for dissolving a nickel-containing material containing cobalt as an impurity, and the nickel and cobalt obtained in the leaching step. After adjusting the pH of the leachate containing, the nickel sulfate obtained through a solvent extraction step of separating into a nickel sulfate solution and a cobalt recovery solution by a solvent extraction method, and a complexing step of complexing the resulting nickel sulfate solution with ammonia It is a manufacturing method of nickel powder characterized by being an ammine complex solution.

  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. It is the manufacturing method of the nickel powder characterized by being.

  The sixth invention of the present invention is a nickel sulfate ammine complex solution obtained by dissolving the nickel sulfate ammine complex solution in the first invention in a post-reaction solution obtained from the reduction step of (2). This is a method for producing nickel powder.

  According to a seventh 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 an eighth aspect of the present invention, the ammonium sulfate concentration in the nickel sulfate ammine complex solution in the fourth to seventh aspects is 100 to 500 g / L, and the ammonium concentration is mol relative to the nickel concentration in the complex solution. The nickel powder production method is characterized in that the ratio is 1.9 or more.

  In the ninth aspect of the present invention, the reduction step of the treatment step (2) and the growth step of the treatment step (3) in the first aspect are performed at a temperature of 150 to 200 ° C. and a pressure of 1.0 to 4. It is a nickel powder manufacturing method characterized in that each treatment is performed while maintaining the pressure in the range of 0 MPa.

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

  The eleventh invention of the present invention is a nickel dust aggregate that processes high-purity nickel powder obtained through the growth step of the treatment step (3) in the first invention into a massive nickel briquette using a briquetting machine. Including a step and a briquette sintering step in which the obtained bulk nickel briquette is sintered in a hydrogen atmosphere at a temperature of 500 to 1200 ° C. to form a sintered nickel briquette. It is the manufacturing method of the nickel powder characterized.

  The twelfth invention of the present invention is a solid-liquid separation process of the reducing slurry obtained in the reducing step of the processing step (2) in the first invention and the growing slurry obtained in the growing step of the processing step (3). A nickel powder production method comprising an ammonium sulfate recovery step of concentrating a post-reaction solution after separating nickel powder as a solid phase component and crystallizing ammonium sulfate to recover ammonium sulfate crystals.

  The thirteenth invention of the present invention is a solid-liquid separation process of the reducing slurry obtained in the reducing step of the processing step (2) in the first invention and the growing slurry obtained in the growing step of the processing step (3). A nickel powder production method comprising an ammonia recovery step of adding an alkali to a post-reaction solution after separation of nickel powder as a solid phase component and heating to volatilize and recover ammonia gas.

  In the fourteenth aspect of the present invention, the ammonia recovered in the ammonia recovery step in the thirteenth aspect is used to adjust the pH in the solvent extraction step described in the fourth aspect and to produce a nickel sulfate ammine complex solution in the complexation step. It is a nickel powder production method characterized in that it is recycled to the ammonia used.

  The fifteenth aspect of the present invention is characterized in that an aqueous sodium polyacrylate solution is added to the dispersing agent in the reduction step of the treatment step (2) of the second aspect in an amount of 2.0 wt% with respect to the seed crystal amount. It is a manufacturing method of nickel powder.

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

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

  In this invention, in the manufacturing method which obtains nickel powder from a nickel sulfate ammine complex solution, by giving the process shown to following (1)-(3) to the process liquid of a hydrometallurgical process, it is more from a nickel sulfate ammine complex solution. It is characterized by producing high-purity nickel powder with few impurities.

  Hereinafter, with reference to the manufacturing flow chart of the high purity nickel powder of the present invention shown in FIG. 1, the manufacturing method of the high purity nickel powder of the present invention will be described.

[Leaching process]
First, the leaching step is a starting material, such as nickel or cobalt mixed sulfide, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, nickel powder, industrial intermediate made of one or more mixtures, etc. In this step, the nickel-containing material is dissolved with sulfuric acid to leached nickel to produce a leachate (a solution containing nickel), which is performed using a known method disclosed in JP-A-2005-350766. .

[Solvent extraction step]
Next, the pH of this leachate is adjusted and subjected to a solvent extraction step.
After this step is obtained in the leaching step, the pH-adjusted leachate is brought into contact with the organic phase, and the components in each phase are exchanged to increase the concentration of certain components in the aqueous phase and other different components Is to lower the concentration of.

  In the present invention, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester or di- (2,4,4-trimethylpentyl) phosphinic acid is selectively used for the organic phase, and an impurity element in the leachate, particularly cobalt, is selectively extracted. A pure nickel sulfate solution is obtained.

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

[Complexing process]
In this complexing step, ammonia gas or ammonia water is added to the high-purity nickel sulfate solution obtained in the solvent extraction step and complexed to produce a nickel sulfate ammine complex, which is a nickel ammine complex. In this step, the nickel sulfate ammine complex solution is formed.
At this time, ammonia is added so that the ammonium concentration is 1.9 or more in molar ratio with respect to the nickel concentration in the solution. When the ammonium concentration of the ammonia to be added is less than 1.9, nickel does not form an ammine complex, and nickel hydroxide precipitates are generated.

In order to adjust the ammonium sulfate concentration, ammonium sulfate can be added in this step. 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 is exceeded, crystals are precipitated, and it is difficult to achieve less than 100 g / L on the metal balance of the process. .
Furthermore, ammonia gas or ammonia water produced in the ammonia recovery step described later can also be used for ammonia gas or ammonia water used in this step.

  Furthermore, nickel hydroxide is used in the nickel-containing material, and (2) by dissolving nickel hydroxide in the post-reaction liquid obtained by solid-liquid separation treatment of the reduction slurry obtained in the reduction step, It can react with ammonium sulfate to form a nickel sulfate ammine complex solution. In the post-reaction solution used, ammonium sulfate remains in the manufacturing process. Further, when the ammonium concentration or the ammonium sulfate concentration does not reach the appropriate range, an appropriate amount of ammonia or ammonium sulfate may be supplemented.

[Nickel powder production process from nickel sulfate ammine complex solution]
The process for producing nickel powder from the nickel sulfate ammine complex solution shown in the processing steps (1) to (3) surrounded by the broken line in FIG. 1 will be described below. In addition, the thick black arrow in a figure has shown the process flow in this process.

(1) Seed crystal addition step To the nickel sulfate ammine complex solution obtained in the complexing step, nickel powder having an average particle size of 0.1 to 5 μm is added as a seed crystal in the form of a nickel powder slurry, and the seed crystal is added. A mixed slurry is formed. The nickel powder used as the seed crystal can be produced by the “seed crystal generation step” described later.
The weight of the seed crystal added at this time is preferably 1 to 100% with respect to the weight of nickel in the nickel sulfate ammine complex solution. If it is less than 1%, the reaction efficiency at the time of reduction in the next step will be significantly reduced. On the other hand, if it is 100% or more, the amount used is large, and the seed crystal production costs high, which is not economical.

Moreover, you may add a dispersing agent simultaneously. Since the seed crystal is dispersed by adding this dispersant, the efficiency of the reduction process of the next process can be increased.
The dispersant used here is not particularly limited as long as it has an acrylate or a sulfonate, but a polyacrylate is preferable because it can be obtained industrially at low cost.

(2) Reduction step Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the processing step (1), and nickel powder in the solution is deposited on the seed crystal by nickel powder generation treatment. Then, a reducing slurry containing the nickel powder formed is formed.
At this time, the reaction temperature is preferably 150 to 200 ° C. If it is less than 150 degreeC, reduction efficiency will fall, and even if it is 200 degreeC or more, there will be no influence on reaction and loss, such as a heat energy, will increase.
Further, the pressure during the reaction is preferably 1.0 to 4.0 MPa. If the pressure is less than 1.0 MPa, the reaction efficiency decreases, and if it exceeds 4.0 MPa, the reaction is not affected and the loss of hydrogen gas increases.

  In the mixed slurry obtained in the seed crystal addition step of the processing step (1), mainly magnesium ions, sodium ions, sulfate ions and ammonium ions are present as impurities, but all remain in the solution. High-purity nickel powder can be produced.

(3) Growth step After the reduced slurry produced in the reduction step of the treatment step (2) is solid-liquid separated, the nickel sulfate ammine complex solution obtained in the complexing step is added to the recovered high-purity nickel powder, A grain growth process for supplying hydrogen gas is performed by the same method as in the reduction step (2) to form a growth slurry containing nickel powder that has undergone grain growth. Thereby, since nickel is reduced and deposited on the high-purity nickel powder, the particles can be grown.

Further, by repeating this growth step a plurality of times, a high-purity nickel powder having a higher bulk density and a larger particle size can be produced.
Further, the obtained nickel powder may be finished into a briquette shape that is coarser, less oxidizable and easy to handle through the following nickel powder ore step and briquette firing step.
Further, 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 preparing a seed crystal to be used, and an outline thereof will be described below.
This step is a step of mixing the high-purity nickel sulfate solution obtained in the solvent extraction step and hydrazine to produce fine nickel powder as seed crystals.
At this time, an alkali may be further mixed, and as an alkali to be used, ammonia is preferably added in a molar ratio of 2 times or more with respect to the amount of nickel in the nickel sulfate solution, and the pH is adjusted to 7 to 12 using caustic soda.

The amount of hydrazine to be used is preferably 0.5 to 2.5 times in molar ratio to the amount of nickel in nickel sulfate. If it is less than 0.5 times, the total amount of nickel does not react, and if it exceeds 2.5 times, the reaction efficiency is not affected and drug loss increases.
The reaction temperature is preferably 25 to 80 ° C., and if it is less than 25 ° C., the reaction time becomes long and it is not practical for industrial application. On the other hand, since the material of the reaction vessel is limited at 80 ° C. or higher, the equipment cost is increased. Furthermore, the particle diameter of the nickel powder produced | generated by adding a small amount of surfactant in this case can be made fine.
The fine nickel powder having an average particle diameter of 0.1 to 5 μm that is the seed crystal thus produced is solid-liquid separated and supplied as a slurry-like nickel powder slurry.

[Nickel dust ore process]
The high-purity nickel powder produced according to the present invention is molded into a product form after drying using a briquetting machine or the like to obtain a massive nickel briquette.
In order to improve the formability of the 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 briquette produced in the briquetting process is roasted and sintered in a hydrogen atmosphere to produce a briquette sintered body. This treatment increases strength and removes trace amounts of ammonia and sulfur components. The roasting and sintering temperature is preferably 500 to 1200 ° C. If it is less than 500 degreeC, sintering will become inadequate and even if it exceeds 1200 degreeC, efficiency will hardly change and the loss of energy will become large.

[Ammonium sulfate recovery process]
Ammonium sulfate and ammonia are contained in the post-reaction liquid generated by the solid-liquid separation process in which each slurry in the reduction process of the processing process (2) and the growth process of the processing process (3) is separated using nickel powder as a solid phase.
Therefore, ammonium sulfate can be recovered as ammonium sulfate crystals by subjecting the solution after the reaction to heat concentration to crystallize ammonium sulfate by performing an ammonium sulfate recovery step.

[Ammonia recovery process]
In addition, ammonia can be recovered by volatilizing ammonia gas by adding alkali to the post-reaction solution and adjusting the pH to 10 to 13, followed by heating.
The alkali used here is not particularly limited, but caustic soda, slaked lime and the like are industrially inexpensive and suitable.
The recovered ammonia gas can be brought into contact with water to generate ammonia water, and the obtained ammonia water can be repeatedly used in the process.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Generation of seed crystals]
To 73 ml of 25% aqueous ammonia, 36 g of sodium hydroxide and 53 ml of 60% hydrazine solution were added to adjust the total liquid volume to 269 ml.
Using a water bath, 273 g of nickel sulfate solution (100 g / L) was dropped into the solution in the beaker while maintaining and stirring so that the liquid temperature became 75 ° C., and held for 30 minutes. Thereafter, solid-liquid separation was performed, and the produced nickel powder was recovered. The average particle diameter 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% aqueous ammonia was added to adjust the total liquid volume to 1000 ml. 7.5 g of the nickel powder obtained in the above “generation of seed crystal” was added to this solution as a seed crystal to prepare a mixed slurry.

(2) Reduction process The mixed slurry prepared in (1) is heated to 185 ° C. while stirring in an autoclave, and hydrogen gas is blown and supplied so that the pressure in the autoclave becomes 3.5 MPa. The nickel powder production | generation process which is 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 high-purity small-diameter nickel powder. The nickel powder recovered at this time was 70 g.

(3) Growth process Next, 191 ml of 25% ammonia water was added to a solution containing 336 g of nickel sulfate and a concentration of 330 g of ammonium sulfate to adjust the total liquid volume 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 stirring in an autoclave, and hydrogen gas was blown and supplied so that the pressure in the autoclave became 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, and high-pure grain-grown nickel powder was recovered.

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

  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 by filtration, and the recovered nickel powder was washed with pure water, and then the impurity quality of the nickel powder was analyzed. The results are shown in Table 1. Mg and Na were not mixed into the nickel powder, and high-purity Ni powder could be generated.

  191 ml of 25% ammonia water was added to a solution containing 75 g of seed crystals prepared in the “growth step” of Example 1, 1.5 g of sodium polyacrylate, 336 g of nickel sulfate, and 330 g of ammonium sulfate, and the total liquid volume was 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 and supplied so that the pressure in the autoclave became 3.5 MPa. After the supply of hydrogen gas, the supply of hydrogen gas was stopped after 1 hour had passed.
After cooling the autoclave, the resulting 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 the reaction was 0.4 g / L, and a reduction rate of 99% or more was obtained.

191 ml of 25% aqueous ammonia was added to a solution containing small-diameter nickel powder collected in Example 3, 336 g of nickel sulfate, and 330 g of ammonium sulfate concentration, and the total liquid volume was adjusted to 1000 ml to prepare a slurry.
The temperature was raised to 185 ° C. while stirring in the autoclave again, and hydrogen gas was blown and supplied so that the pressure in the autoclave became 3.5 MPa. After the grain growth treatment was performed, solid-liquid separation treatment by filtration was performed. The grain-grown nickel powder was recovered.
This operation was repeated to further grow nickel powder.

  As shown in FIG. 2, the nickel powder obtained in Example 4 is grown by repeating the growth process and performing reduction to increase the particle size. On the other hand, the bulk density decreases as the number of repeated reductions increases. Moreover, since the nickel powder produced | generated from the SEM image of FIG. 3 is carrying out the particle | grain shape with the unevenness | corrugation on the surface, it is coarser and easier than nickel powder at the time of using lignin sulfonate as a dispersing agent shown in the comparative example 3. Soluble nickel powder could be obtained.

In addition, the sulfur quality in the obtained nickel powder was 0.04%.
Therefore, the nickel powder was heated to 1000 ° C. in a 2% hydrogen atmosphere and roasted for 60 minutes. The sulfur quality in the nickel powder obtained after roasting was 0.008%, and the sulfur quality 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 nickel sulfate solution having a nickel concentration of 120 g / L, 120 g of nickel hydroxide was obtained.
The nickel hydroxide was mixed into 1700 ml of a mixed solution of nickel sulfate solution having a nickel concentration of 30 g / L and ammonium sulfate solution having an ammonia concentration of 40 g / L imitating the post-reaction solution obtained in the reduction step, and mixed by stirring and dissolving. A slurry was prepared.

  Next, the slurry is heated to 185 ° C. while being stirred in an autoclave, and hydrogen gas is blown and supplied so that the pressure in the autoclave becomes 3.5 MPa. Through the liquid separation process, the grain-grown nickel powder was recovered.

(Comparative Example 1)
Without adding seed crystals, 45 ml of pure water, 20 g of nickel sulfate hexahydrate, 15 g of ammonium sulfate, and 10 ml of 28% ammonia water were placed in an autoclave, and hydrogen gas was supplied to 3.5 MPa while stirring. After raising the temperature to 185 ° C., the temperature was maintained for 6 hours. When the inside of the autoclave was confirmed after cooling, the deposit adhered as a scale on the container and the stirring blade, and powdered nickel could not be produced.

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

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

Claims (15)

In the production process of producing nickel powder from a nickel sulfate ammine complex solution,
The manufacturing method of the nickel powder characterized by performing the process shown to following (1) to (3).
(1) A seed crystal addition step of adding nickel powder having an average particle size of 0.1 to 5 μm as a seed crystal to the nickel sulfate ammine complex solution to form a mixed slurry.
(2) Hydrogen gas is blown into the mixed slurry obtained in the seed crystal addition step of the processing step (1), and the nickel component in the mixed slurry is reduced to include nickel powder formed by precipitation on the seed crystal. A reduction process for forming 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 the recovered nickel powder is mixed with a nickel sulfate ammine complex solution. A growth step of forming a growth slurry containing high-purity nickel powder, in which hydrogen gas is blown into the solution to which nickel is added, and the nickel powder is grown.   The dispersant is further added to the mixed slurry when the seed crystal in the seed crystal addition step of the processing step (1) is added to the nickel sulfate ammine complex solution to form a mixed slurry. The manufacturing method of the nickel powder of 1.   The addition amount of the seed crystal to be added in the seed crystal addition step of the treatment step (1) is an amount that becomes 1 to 100% with respect to the weight of nickel in the nickel sulfate ammine complex solution. The manufacturing method of the nickel powder of 1 or 2. The nickel sulfate ammine complex solution is
A leaching step of dissolving a nickel-containing material containing cobalt as an impurity;
After adjusting the pH of the leachate containing nickel and cobalt obtained in the leaching step, a solvent extraction step of 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 ammine 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.   5. The nickel according to claim 4, wherein the nickel-containing material is at least one of a mixed sulfide of nickel and cobalt, crude nickel sulfate, nickel oxide, nickel hydroxide, nickel carbonate, and metal nickel powder. Powder manufacturing method. The nickel sulfate ammine complex solution is
2. The method for producing nickel powder according to claim 1, which is a nickel sulfate ammine complex solution obtained by dissolving nickel hydroxide in a post-reaction solution obtained from the reduction step.   Nickel according to claim 4 or 5, characterized in that the organic phase of the solvent extraction method is 2-ethylhexylphosphonic acid mono 2-ethylhexyl ester or di- (2,4,4-trimethylpentyl) phosphinic acid. Powder manufacturing method. The ammonium sulfate concentration in the nickel sulfate ammine complex solution is 100 to 500 g / L,
And the ammonium concentration is 1.9 or more by molar ratio with respect to the nickel concentration in the said complex solution, The manufacturing method of the nickel powder of any one of Claims 4-7 characterized by the above-mentioned.   The reduction step of the treatment step (2) and the growth step of the treatment step (3) perform each treatment 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 method for producing nickel powder according to claim 1, characterized in that:   The said dispersing agent contains an acrylate or a sulfonic acid, The manufacturing method of the nickel powder of Claim 2 characterized by the above-mentioned. Nickel dust ore step for processing the high-purity nickel powder obtained through the growth step of the treatment step (3) into a massive nickel briquette using a briquetting machine,
The obtained bulk nickel briquette is subjected to a sintering process under a holding condition at a temperature of 500 to 1200 ° C. in a hydrogen atmosphere, and includes a briquette sintering step of forming a nickel briquette of a sintered body. The manufacturing method of the nickel powder of Claim 1.   After reaction after separating the nickel powder as a solid phase component by solid-liquid separation of the reducing slurry obtained in the reducing step of the treating step (2) and the growing slurry obtained in the growing step of the treating step (3) The method for producing 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 separating the nickel powder as a solid phase component by solid-liquid separation of the reducing slurry obtained in the reducing step of the treating step (2) and the growing slurry obtained in the growing step of the treating step (3) The method for producing nickel powder according to claim 1, further comprising an ammonia recovery step in which an alkali is added to the liquid and heated to volatilize and recover the ammonia gas.   The ammonia recovered in the ammonia recovery step is circulated and used as ammonia used for pH adjustment in the solvent extraction step according to claim 4 and generation of a nickel sulfate ammine complex solution in the complexation step. The manufacturing method of the nickel powder of description.   The method for producing nickel powder according to claim 2, wherein a sodium polyacrylate aqueous solution is added in an amount of 2.0 wt% with respect to the seed crystal amount to the dispersant in the reduction step of the treatment step (2).