U.S. patent application number 16/080363 was filed with the patent office on 2021-07-01 for method for producing nickel powder.
The applicant listed for this patent is SUMITOMO METAL MINING CO., LTD.. Invention is credited to Shin-ichi Heguri, Osamu Ikeda, Yohei Kudo, Yoshitomo Ozaki.
Application Number | 20210197266 16/080363 |
Document ID | / |
Family ID | 1000005495620 |
Filed Date | 2021-07-01 |
United States Patent
Application |
20210197266 |
Kind Code |
A1 |
Heguri; Shin-ichi ; et
al. |
July 1, 2021 |
METHOD FOR PRODUCING NICKEL POWDER
Abstract
Provided is a method for controlling generation of scaling in a
reaction vessel to reduce time and cost required for removal of the
scaling in the process of producing nickel powder from a solution
containing a nickel ammine sulfate complex. This is a method for
producing nickel powder, including: adding, to the solution
containing the nickel ammine sulfate complex, seed crystals in an
amount of 0.3 times or more and 3 times or less the weight of
nickel in the solution to form a slurry; and blowing hydrogen gas
into the slurry to reduce a nickel complex ion and to thereby form
a nickel precipitate.
Inventors: |
Heguri; Shin-ichi;
(Niihama-shi, JP) ; Ozaki; Yoshitomo;
(Niihama-shi, JP) ; Ikeda; Osamu; (Niihama-shi,
JP) ; Kudo; Yohei; (Niihama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUMITOMO METAL MINING CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000005495620 |
Appl. No.: |
16/080363 |
Filed: |
February 8, 2017 |
PCT Filed: |
February 8, 2017 |
PCT NO: |
PCT/JP2017/004499 |
371 Date: |
August 28, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 9/24 20130101; B22F
2301/15 20130101; B22F 2201/013 20130101; B22F 2304/10 20130101;
B22F 1/0011 20130101 |
International
Class: |
B22F 9/24 20060101
B22F009/24; B22F 1/00 20060101 B22F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 29, 2016 |
JP |
2016-038185 |
Claims
1. A method of producing nickel powder, comprising: adding, to a
solution containing a nickel ammine sulfate complex, seed crystals
having a particle size of 1 to 20 .mu.m in an amount of 0.3 to 3
times a weight of nickel in the solution to form a slurry; charging
the slurry into a reaction vessel, maintaining a liquid phase
portion occupied by the slurry and a gaseous phase portion other
than the liquid phase portion within the reaction vessel; blowing
hydrogen gas into the slurry to reduce a nickel complex ion and to
thereby produce and recover nickel powder in which a nickel
precipitate is formed on a surface of the seed crystals; and
performing hydrogen reduction by adding the solution containing the
nickel ammine sulfate complex to the recovered nickel powder in
which the nickel precipitate is formed on the surface of the seed
crystals and blowing hydrogen gas into the nickel powder to
precipitate nickel on the nickel precipitate and to thereby produce
grown nickel powder.
2. The method of producing nickel powder according to claim 1,
wherein a polyacrylate salt dispersant is added to the slurry in an
amount of 0.5 to 5% based on the weight of the seed crystals added
to the slurry.
3. The method of producing nickel powder according to claim 1,
wherein the hydrogen reduction is repeated to precipitate on the
nickel precipitate and to thereby obtain further grown nickel
powder.
4. The method of producing nickel powder according to claim 1,
wherein a temperature of the slurry is 150 to 200.degree. C. when
hydrogen gas is blown into the slurry.
5. The method of producing nickel powder according to claim 1,
wherein a pressure of the gaseous phase portion in the reaction
vessel is in a range of 1.0 to 4.0 MPa when hydrogen gas is blown
into the slurry.
6. The method of producing nickel powder according to claim 1,
wherein the seed crystals are nickel powder having the particle
size of 1 to 20 .mu.m.
7. The method of producing nickel powder according to claim 1,
wherein the hydrogen reduction is repeated to precipitate on the
nickel precipitate and to thereby obtain further grown nickel
powder.
8. The method of producing nickel powder according to claim 1,
wherein a temperature of the slurry is 150 to 200.degree. C. when
hydrogen gas is blown into the slurry.
9. The method of producing nickel powder according to claim 1,
wherein a pressure of the gaseous phase portion in the reaction
vessel is in a range of 1.0 to 4.0 MPa when hydrogen gas is blown
into the slurry.
10. The method of producing nickel powder according to claim 1,
wherein the seed crystals are nickel powder having the particle
size of 1 to 20 .mu.m.
Description
BACKGROUND
Field of the Invention
[0001] The present invention relates to a method for controlling
scaling in a reaction vessel in a method for producing nickel
powder from a solution containing a nickel ammine sulfate complex.
Particularly, the present invention can be applied to a treatment
of an in-process intermediate solution generated from a nickel
hydrometallurgical process.
Related Art
[0002] Methods for producing fine nickel powder have been known
including atomization methods of dispersing molten nickel in gas or
water to obtain fine powder, and dry processes, such as CVD
processes, of volatilizing nickel, and reducing the nickel in a
gaseous phase to obtain nickel powder as described in Japanese
Patent Application Laid-Open No. 2005-505695.
[0003] Methods for producing nickel powder by a wet process include
a method of producing nickel powder using a reducing agent as
described in Japanese Patent Application Laid-Open No. 2010-242143,
and an atomization thermal decomposition method of atomizing a
nickel solution in a reduction atmosphere at a high temperature to
obtain a nickel powder through a thermal decomposition reaction as
described in Japanese Patent No. 4286220.
[0004] However, these methods are not economical because these
methods require expensive reagents and a large amount of
energy.
[0005] In contrast, a method as described in "The Manufacture and
properties of Metal powder produced by the gaseous reduction of
aqueous solutions", Powder metallurgy, No. 1/2 (1958), pp. 40-52 is
industrially inexpensive and useful, in which hydrogen gas is fed
to a nickel ammine sulfate complex solution to reduce nickel ions
in the complex solution, obtaining a nickel powder.
[0006] This method involves the following process: a small amount
of fine particles called seed crystals is added, and a reducing
agent is fed thereto to grow the seed crystals into a powder having
a predetermined particle size. However, in this method, the
so-called scaling, which is part of nickel precipitated on the
walls of the reaction container in the apparatus rather than on the
seed crystals, may be formed in the reaction vessel, causing
failure such as clogging of the pipes.
[0007] For this reason, an operation of removing scale is required
by, e.g., stopping of the apparatus regularly, resulting in a
reduction in productivity and an increase in maintenance cost
required for the removal. Accordingly, the problem has been control
of the generation of scaling as much as possible.
[0008] In such circumstances, the present invention provides a
method for controlling the generation of scaling in a reaction
vessel to reduce time and cost required for removal of the scaling
in the process of producing nickel powder from a solution
containing a nickel ammine sulfate complex.
SUMMARY
[0009] A first aspect of the present invention to solve the above
problem is a method for producing nickel powder, including: adding,
to a solution containing a nickel ammine sulfate complex, seed
crystals having a particle size of 1 to 20 .mu.m in an amount of
0.3 times or more and 3 times or less the weight of nickel in the
solution to form a slurry; charging the slurry into a reaction
vessel, maintaining a liquid phase portion occupied by the slurry
and a gaseous phase portion other than the liquid phase portion
within the reaction vessel; blowing hydrogen gas into the slurry to
reduce a nickel complex ion and to thereby produce and recover
nickel powder in which a nickel precipitate is formed on a surface
of the seed crystals; and performing hydrogen reduction by adding
the solution containing the nickel ammine sulfate complex to the
recovered nickel powder in which the nickel precipitate is formed
on the surface of the seed crystals and blowing hydrogen gas into
the nickel powder to precipitate nickel on the nickel precipitate
and to thereby produce grown nickel powder.
[0010] A second aspect of the present invention is a method for
producing nickel powder, wherein of a polyacrylate salt dispersant
is added to the slurry according to the first aspect in an amount
of 0.5 to 5% based on the weight of the seed crystals added to the
slurry.
[0011] A third aspect of the present invention is a method for
producing nickel powder, wherein the hydrogen reduction according
to the first and second aspect is to precipitate nickel on the
nickel precipitate and to thereby obtain further grown nickel
powder.
[0012] A fourth aspect of the present invention is a method for
producing nickel powder, wherein the temperature of the slurry is
150 to 200.degree. C. when hydrogen gas is blown into the slurry
according to the first to third aspects.
[0013] A fifth aspect of the present invention is a method for
producing nickel powder, wherein the pressure of the gaseous phase
portion in the reaction vessel is in the range of 1.0 to 4.0 MPa
when hydrogen gas is blown into the slurry according to the first
to fourth aspects.
[0014] Further, the seed crystals according to the first to fifth
aspects are nickel powder having the particle size of 1 to 20
.mu.m.
[0015] The present invention can control the generation of scaling.
For this reason, the frequency of removal of scale can be reduced,
resulting in a reduction in time and cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a diagram illustrating a relation between the
amount of nickel powder to be added, the number of repetitions, and
the amount of scaling generated.
DETAILED DESCRIPTION
[0017] The present invention is a method for producing nickel
powder by adding seed crystals to a nickel ammine sulfate complex
solution, and blowing hydrogen gas thereinto to produce a nickel
powder.
[0018] Hereinafter, the method for producing nickel powder
according to the present invention will be described.
[Nickel Ammine Sulfate Complex Solution]
[0019] A nickel ammine sulfate complex solution that can be used in
the present invention is not particularly limited, but it is
suitable to use a nickel ammine sulfate complex solution obtained
by dissolving a nickel-containing material, such as an industrial
intermediate including one or a mixture of two or more selected
from nickel and cobalt mixed sulfide, crude nickel sulfate, nickel
oxide, nickel hydroxide, nickel carbonate, and nickel powder, with
sulfuric acid or ammonia to prepare a nickel-containing leachate
(solution containing nickel), subjecting the nickel-containing
leachate to a liquid-purification step such as solvent extraction,
ion exchange, or neutralization to remove impurity elements in the
solution, and adding ammonia to the resulting solution.
[Preparation of Slurry]
[0020] In this step, seed crystals are added to the nickel ammine
sulfate complex solution to prepare a slurry.
[0021] The seed crystals added here are preferably a powder having
a particle size of 20 .mu.m or less. A nickel powder is suitable as
a substance which does not contaminate the final nickel
precipitate. The nickel powder used as the seed crystals can be
prepared, for example, by adding a reducing agent such as hydrazine
to the nickel ammine sulfate complex solution.
[0022] The weight of the seed crystals added here is preferably 0.3
times or more and 3 times or less the weight of nickel in the
solution. An amount of less than 0.3 times the weight of nickel in
the solution cannot achieve a sufficient effect of reducing
scaling. An amount of more than 3 times has no influences over the
effect; rather, this results in addition of excess crystal
seeds.
[0023] Then, a dispersant may be added to disperse the seed
crystals in the slurry. A dispersant used here is not particularly
limited as long as it has polyacrylate salt, but sodium
polyacrylate, which is industrially available at low cost, is
preferable. The amount of the dispersant to be added is preferably
0.5 to 5% based on the weight of the seed crystals. An amount of
less than 0.5% cannot achieve the dispersion effect. An amount of
more than 5% has no influences over the dispersion effect; rather,
this results in addition of an excess dispersant.
[0024] Next, the slurry prepared by the addition of the seed
crystals or the seed crystals and the dispersant is charged into a
reaction vessel in a container resistant to high pressure and high
temperature, forming a liquid phase portion occupied by the slurry
and a gaseous phase portion in the reaction vessel. Subsequently,
hydrogen gas is blown into the slurry in the reaction vessel to
reduce a nickel complex ion in the solution and precipitate nickel
on the seed crystals added.
[0025] At this time, the reaction temperature is preferably in the
range of 150 to 200.degree. C. A reaction temperature of less than
150.degree. C. reduces the efficiency of reduction. A reaction
temperature of more than 200.degree. C. has no influences over the
reaction; rather, such a reaction temperature increases loss of
thermal energy, and is not suitable.
[0026] Furthermore, the pressure of the gaseous phase portion in
the reaction vessel during the reaction is preferably 1.0 to 4.0
MPa. If the pressure is less than 1.0 MPa, reaction efficiency will
be reduced, and even if the pressure exceeds 4.0 MPa, there will be
no influence on the reaction, and the loss of hydrogen gas will
increase.
[0027] A precipitate of nickel is formed on the seed crystals
through the reduction and the precipitation treatment under such
conditions so that nickel can be extracted and recovered from the
solution in the form of a fine powdery precipitate by the effect of
the dispersant.
[0028] The nickel powder thus produced can be used in, for example,
an application to nickel pastes as an inner constitutional
substance for stacked ceramic capacitors. Besides, particles of the
nickel powder can be grown through repetition of the above hydrogen
reduction to produce high purity nickel metal.
EXAMPLES
[0029] Hereinafter, the present invention will be described with
reference to Examples.
Example 1
[0030] 191 ml of 25% aqueous ammonia, 22.5 g of 1 .mu.m nickel
powder (0.3 times the weight of nickel in a mixed solution used
here) as seed crystals, and 0.4 g of sodium polyacrylate (42%
solution) were added to the mixed solution of a nickel sulfate
solution containing nickel equivalent to 75 g and 330 g of ammonium
sulfate, and the total volume of the mixture was adjusted to 1000
ml to prepare a slurry.
[0031] The resulting slurry was then charged into an internal
cylindrical can of an autoclave used as a reaction vessel to define
a liquid phase portion and a gaseous phase portion. The slurry was
heated to and held at 185.degree. C. with stirring. In this state,
hydrogen gas was blown and fed into the slurry so that the pressure
of the gaseous phase portion in the internal cylindrical can of the
autoclave became 3.5 MPa, to perform a reduction treatment.
Thereby, a reduced slurry was generated. After the lapse of 60
minutes from the start of feeding hydrogen gas, the feed of
hydrogen gas was stopped, and the internal cylindrical can was
cooled.
[0032] After the cooling, the reduced slurry in the internal
cylindrical can was filtered to recover nickel powder. To the
recovered nickel precipitate, a nickel sulfate solution containing
nickel equivalent to 75 g, a solution containing 330 g of ammonium
sulfate, and 191 ml of 25% aqueous ammonia were added and the total
amount of the solution was adjusted to 1000 ml to prepare an
adjusted slurry.
[0033] The adjusted slurry was reacted in the autoclave in the same
manner as described above, and a thus recovered nickel precipitate
was again reacted in the manner described above. This operation was
repeated to grow nickel powder.
[0034] In each operation, the reduced slurry in the internal
cylindrical can was extracted, and was dried. The weight of the
internal cylindrical can was measured to measure a change in weight
before and after the reaction.
[0035] The results are shown in FIG. 1 (see a legend of 22.5
g).
[0036] As seen from FIG. 1, if the seed crystal nickel powder is
22.5 g (proportion of addition: 30%), the change in weight is small
according to "the number of repetitions" and the generation of
scaling can be reduced.
Example 2
[0037] A nickel powder was grown under the same condition as in
Example 1 except that the nickel powder as seed crystals was added
in an amount of 3.0 times the weight of nickel in the mixed
solution, i.e., 225 g.
[0038] The results similar to those in Example 1 were obtained.
Even if the number of repetitions was increased, the weight of
scaling generated was 20 g or less each time.
Comparative Example 1
[0039] The growth was repeatedly performed in the same manner as in
Example 1 except that initially 15.0 g of 1 .mu.m nickel powder
(proportion of addition: 20%) and 0.3 g of sodium polyacrylate (42%
solution) were added.
[0040] As a result, as shown in FIG. 1 (see a legend of 15 g), it
is found that the amount of scaling increased according to the
number of repetitions of the reaction, i.e., as the repetition of
the reaction was larger, although the increase was mild.
Comparative Example 2
[0041] The growth was repeatedly performed in the same manner as in
Example 1 except that initially 7.5 g of 1 .mu.m nickel powder
(proportion of addition: 10%) and 0.1 g of sodium polyacrylate (42%
solution) were added.
[0042] As a result, as shown in FIG. 1 (see a legend of 7.5 g), it
is found that the amount of scaling significantly increased at the
second reaction in the repetitions, and the tendency continued
thereafter.
* * * * *