U.S. patent application number 15/738244 was filed with the patent office on 2018-06-21 for method for producing cobalt powder.
The applicant listed for this patent is SUMITOMO METAL MINING CO., LTD.. Invention is credited to Yasuo Doi, Shin-ichi Heguri, Osamu Ikeda, Yohei Kudo, Yoshitomo Ozaki, Kazuyuki Takaishi, Ryo-ma Yamaguma.
Application Number | 20180169764 15/738244 |
Document ID | / |
Family ID | 57685569 |
Filed Date | 2018-06-21 |
United States Patent
Application |
20180169764 |
Kind Code |
A1 |
Yamaguma; Ryo-ma ; et
al. |
June 21, 2018 |
METHOD FOR PRODUCING COBALT POWDER
Abstract
Provided is a method for producing cobalt powder with high
reaction efficiency by controlling the amount of added seed
crystals when cobalt powder is produced from a solution containing
a cobalt ammine sulfate complex. The method sequentially includes:
a mixing step of adding, to the solution containing a cobalt ammine
sulfate complex, cobalt powder as seed crystals in an amount of 1.5
times or more and 3.0 times or less the amount of cobalt contained
in the solution and then adding a dispersant in an amount of 1.5%
by weight to 3.0% by weight of the added seed crystals to form a
mixture slurry; and a reduction and precipitation step of charging
a reaction vessel with the mixture slurry and then blowing hydrogen
gas into the mixture slurry to reduce cobalt complex ions contained
in the mixture slurry to form cobalt precipitate on the surface of
the seed crystals.
Inventors: |
Yamaguma; Ryo-ma;
(Niihama-shi, JP) ; Ozaki; Yoshitomo;
(Niihama-shi, JP) ; Takaishi; Kazuyuki;
(Niihama-shi, JP) ; Heguri; Shin-ichi;
(Niihama-shi, JP) ; Ikeda; Osamu; (Niihama-shi,
JP) ; Kudo; Yohei; (Niihama-shi, JP) ; Doi;
Yasuo; (Niihama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUMITOMO METAL MINING CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
57685569 |
Appl. No.: |
15/738244 |
Filed: |
June 27, 2016 |
PCT Filed: |
June 27, 2016 |
PCT NO: |
PCT/JP2016/069030 |
371 Date: |
December 20, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2999/00 20130101;
B22F 9/26 20130101; C22B 23/0446 20130101; B22F 2998/00 20130101;
C22B 23/043 20130101; B22F 2301/15 20130101 |
International
Class: |
B22F 9/26 20060101
B22F009/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2015 |
JP |
2015-134743 |
Claims
1. A method of producing cobalt powder from a cobalt-containing
material of an industrial intermediate including one or a mixture
of two or more selected from cobalt and cobalt mixed sulfide, crude
cobalt sulfate, cobalt oxide, cobalt hydroxide, cobalt carbonate,
and cobalt powder, the method sequentially comprising: a mixing
step of adding, to a solution containing a cobalt ammine sulfate
complex in which a concentration of ammonium sulfate is in a range
of 10 to 500 g/L and the cobalt-containing material is a cobalt
supply source, cobalt powder having an average particle size of 0.1
to 5 .mu.m as seed crystals in an amount of 1.5 times or more and
3.0 times or less an amount of cobalt contained in the solution and
then adding a dispersant in an amount of 1.5% by weight to 3.0% by
weight of the seed crystals added to form a mixture slurry; and a
reduction and precipitation step of charging a reaction vessel with
the mixture slurry, heating to a temperature of 150 to 200.degree.
C., blowing hydrogen gas into the mixture slurry while keeping the
temperature, and maintaining a pressure of a gas phase part in the
reaction vessel at a range of 1.0 to 4.0 MPa to reduce cobalt
complex ions contained in the mixture slurry to form cobalt
precipitate on a surface of the seed crystals.
2-4. (canceled)
Description
BACKGROUND
Field of the Invention
[0001] The present invention relates to a method for producing
cobalt powder having high reaction efficiency when cobalt powder is
produced from a solution containing a cobalt ammine sulfate
complex, and particularly, the present invention can be applied to
the treatment of an in-process intermediate solution generated from
a cobalt hydrometallurgical process.
Description of the Related Art
[0002] Examples of known methods for producing fine cobalt powder
include dry methods such as an atomizing method of dispersing
molten cobalt in a gas or in water to obtain fine powder and a CVD
method of volatilizing cobalt and reducing it in a vapor phase to
thereby obtain cobalt powder as disclosed in Japanese Patent
Laid-Open No. 2005-505695.
[0003] Further, examples of methods for producing cobalt powder by
a wet process include a method of producing cobalt powder using a
reducing agent as disclosed in Japanese Patent No. 5407495 and a
spray pyrolysis method in which cobalt powder is obtained by
pyrolysis reaction by spraying a cobalt solution into a reducing
atmosphere at high temperatures as disclosed in Japanese Patent No.
4286220.
[0004] However, these methods are not economical because they
require expensive reagents and a large amount of energy.
[0005] On the other hand, a method of obtaining cobalt powder by
feeding hydrogen gas into a cobalt ammine sulfate complex solution
to reduce cobalt ions in the complex solution as shown 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. However, there has
been a problem that cobalt powder particles obtained by this method
are easily coarsened.
[0006] Particularly, when particles are intended to be generated
from an aqueous solution and grown, there is used a method of
obtaining a powder having a predetermined particle size by allowing
a small amount of fine crystals called seed crystals to coexist and
feeding a reducing agent thereto to grow the seed crystals.
[0007] According to the above method, high reaction efficiency
cannot be obtained, depending on the cobalt concentration in the
aqueous solution to be used and the type of seed crystals, and the
yield will decrease, which leads to an increase in cost.
[0008] Generally, in such a case, it is possible to improve
reaction efficiency by reducing the particle size of seed crystals
to increase the reaction field. However, time and effort are
required in order to reduce the particle size of seed crystals.
Further, in the case where seed crystals made of different types of
metals are used, there arises a problem such that the purity of
products decreases because the seed crystal component remains.
[0009] Therefore, there has been required a method of having high
reaction efficiency, without using different types of metals as
seed crystals and not necessarily using seed crystals having a
small particle size.
[0010] In such a situation, the present invention provides a method
for producing cobalt powder by obtaining high reaction efficiency
by controlling the amount of added seed crystals when cobalt powder
is produced from a solution containing a cobalt ammine sulfate
complex.
SUMMARY
[0011] A first aspect of the present invention to solve such a
problem is a method for producing cobalt powder from a
cobalt-containing material of an industrial intermediate including
one or a mixture of two or more selected from cobalt and cobalt
mixed sulfide, crude cobalt sulfate, cobalt oxide, cobalt
hydroxide, cobalt carbonate, and cobalt powder, the method
sequentially including: a mixing step of adding, to a solution
containing a cobalt ammine sulfate complex in which a concentration
of ammonium sulfate is in a range of 10 to 500 g/L and the
cobalt-containing material is a cobalt supply source, cobalt powder
having an average particle size of 0.1 to 5 .mu.m as seed crystals
in an amount of 1.5 times or more and 3.0 times or less the amount
of cobalt contained in the solution and then adding a dispersant in
an amount of 1.5% by weight to 3.0% by weight of the added seed
crystals to form a mixture slurry; and a reduction and
precipitation step of charging a reaction vessel with the mixture
slurry, heating to a temperature of 150 to 200.degree. C., blowing
hydrogen gas into the mixture slurry while keeping the temperature,
and maintaining a pressure of a gas phase part in the reaction
vessel to a range of 1.0 to 4.0 MPa to reduce cobalt complex ions
contained in the mixture slurry to form cobalt precipitate on a
surface of the seed crystals.
[0012] According to the present invention, in the method of adding
a dispersant to a cobalt ammine complex solution and subjecting the
resulting mixture to hydrogen reduction under high temperatures and
high pressures, cobalt powder can be produced at high reaction
efficiency.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a production flow chart of the method for
producing cobalt powder according to the present invention.
[0014] FIG. 2 is a SEM image showing the appearance of cobalt
powder produced in Example 1.
DETAILED DESCRIPTION
[0015] The method for producing high purity cobalt powder according
to the present invention is a method for producing cobalt powder in
which, when seed crystals are added to a cobalt ammine sulfate
complex solution using a high-pressure vessel such as an autoclave
and the resulting mixture is subjected to pressurized hydrogen
reduction treatment including reduction treatment with hydrogen at
high temperatures and high pressures, cobalt powder is produced by
adding cobalt powder as seed crystals in an amount 1.5 times or
more and 10.0 times or less the amount of cobalt in the starting
solution, preferably 1.5 times or more and 3.0 times or less, and
more preferably 2.0 times.
[0016] Hereinafter, the method for producing cobalt powder
according to the present invention will be described with reference
to the production flow chart shown in FIG. 1.
[Cobalt Ammine Sulfate Complex Solution]
[0017] Examples of a suitable cobalt ammine sulfate complex
solution used in the present invention include, but are not limited
to, a cobalt ammine sulfate complex solution obtained by dissolving
a cobalt-containing material such as an industrial intermediate
including one or a mixture of two or more selected from cobalt and
cobalt mixed sulfide, crude cobalt sulfate, cobalt oxide, cobalt
hydroxide, cobalt carbonate, cobalt powder, and the like with
sulfuric acid or ammonia to obtain a cobalt leaching solution
(solution containing cobalt), subjecting the cobalt leaching
solution to a purification step such as solvent extraction, ion
exchange, and neutralization to obtain a solution from which
impurity elements in the cobalt leaching solution have been
removed, and adding ammonia to the resulting solution to form the
cobalt ammine sulfate complex solution, in which cobalt is
contained in the form of cobalt complex ions.
[Mixing Step]
[0018] In this step, a mixture slurry is produced by adding seed
crystals to the cobalt ammine sulfate complex solution produced
above and adding a dispersant thereto depending on the amount of
the added seed crystals.
[0019] Cobalt powder is used as the seed crystals to be added
here.
[0020] Although commercially available products may be used as the
cobalt powder to be used as the seed crystals, it is more preferred
to repeatedly use a part of products obtained by the production
method of the present invention.
[0021] The particle size of the cobalt powder preferably has an
average particle size of about 0.1 to 5 .mu.m, and particularly
preferably has a particle size of around 1 .mu.m, where the
particle size does not vary but is uniform.
[0022] If the particle size is too small, the cobalt powder
obtained in the reaction will be too small, which has difficulty in
handling and is not preferred. On the other hand, if the particle
size is too large, the cobalt powder will easily settle during
stirring, which poses a problem that uniform cobalt powder is not
easily obtained.
[0023] The amount of cobalt powder to be added is 1.5 times or more
and 3.0 times or less, preferably 2.0 times the amount of cobalt
contained in the original solution, in order to maintain reaction
efficiency.
[0024] If the amount of cobalt powder added is less than 1.5 times
of the amount of cobalt contained in the original solution, high
reaction efficiency cannot be obtained because the number of seed
crystals is insufficient, reducing reaction fields. Further, even
if the amount of cobalt powder added is more than 3.0 times,
reaction efficiency will not be improved, and the efficiency will
not be improved considering that too much time and effort and cost
are required. The number of seed crystals will be rather too large,
and the growth of the cobalt powder obtained will be insufficient,
reducing the particle size. Therefore, when the cobalt powder is
used as products, a problem in use will easily occur, such as
requiring time and effort in handling thereof. Further, a problem
of properties, such as being easily dissolved or oxidized, will
occur, which is not preferred.
[0025] Furthermore, when a dispersant is added so that it is
contained at a concentration in the range of 1.5% by weight or more
and 3.0% by weight or less relative to the amount of seed crystals
added to the cobalt ammine sulfate complex solution, the added seed
crystals are dispersed more uniformly, and desired cobalt powder is
thus more easily obtained, which is desirable.
[0026] Further, the concentration of ammonium sulfate in the
solution is preferably in the range of 10 to 500 g/L.
[0027] If the concentration is more than 500 g/L, the solubility
will be exceeded, and crystals will be precipitated. With respect
to the lower limit, since ammonium sulfate is newly produced by
reaction, it is difficult to achieve a concentration of less than
10 g/L.
[Reduction and Precipitation Step]
[0028] Next, a reaction vessel resistant to high pressure and high
temperature is charged with the slurry formed by adding seed
crystals in the previous step, and hydrogen gas is blown into the
slurry stored in the reaction vessel to reduce cobalt complex ions
in the slurry to precipitate cobalt on the seed crystals
contained.
[0029] The temperature of the mixture slurry at this time, that is,
reaction temperature, is preferably in the range of 150 to
200.degree. C. If the reaction temperature is less than 150.degree.
C., reduction efficiency will be reduced, and even if it is more
than 200.degree. C., the reaction will not be affected, but the
loss of thermal energy will increase. Therefore, these temperatures
are not suitable.
[0030] Further, the pressure of the gas phase part in the reaction
vessel (refers to a space in the reaction vessel remaining after
the solution is stored in the reaction vessel) during the reaction
is preferably maintained in the range of 1.0 to 4.0 MPa by
controlling the feed rate of hydrogen gas. If the pressure is less
than 1.0 MPa, reaction efficiency will be reduced, which is not
preferred. Further, even if the pressure is higher than 4.0 MPa,
the reaction efficiency will not be affected, but the loss of
hydrogen gas will increase.
[0031] In this regard, when hydrogen gas is blown into the mixture
slurry, the cobalt complex ions in the slurry can also be reduced
either by directly blowing hydrogen gas into the liquid in the
reaction vessel or by blowing hydrogen gas into the gas phase part
in the reaction vessel.
[0032] A precipitate of cobalt is formed on the seed crystals by
reduction and precipitation treatment of the present invention, and
the cobalt contained in the solution can be recovered and
repeatedly used as a precipitate of fine powdered cobalt.
[0033] As described above, by producing the seed crystals of cobalt
powder in fine powder form which can be used as seed crystals and
repeating hydrogen reduction, particles in which cobalt precipitate
is provided on the surface of the seed crystals are formed, and the
particles can be grown up to produce high purity cobalt metal.
EXAMPLES
[0034] The present invention will be described below using
Examples.
Example 1
[Mixing Step]
[0035] To a cobalt sulfate solution containing 75 g of cobalt, was
added 465 g of ammonium sulfate, and thereto was added 191 ml of
25% aqueous ammonia to form an original solution. A mixture slurry
containing a cobalt ammine sulfate complex containing seed crystals
was prepared by adding, to the original solution, cobalt powder
having an average particle size of about 0.1 to 5 .mu.m, as seed
crystals, in an amount of 150 g which is 2.0 times the amount of
cobalt in the original solution, further adding 40 wt % polyacrylic
acid, as a dispersant, in an amount 2.0% by weight relative to the
amount of the seed crystals, and then adjusting the total volume of
the solution to 1000 ml.
[Reduction and Precipitation Step]
[0036] Next, an inner cylinder of an autoclave was charged with the
mixture slurry; the mixture slurry was heated to 185.degree. C.
with stirring after the autoclave was sealed; hydrogen gas was
blown into the mixture slurry while keeping the temperature; and
hydrogen gas was fed from its cylinder so as to maintain the
pressure in the inner cylinder of the autoclave at 3.5 MPa.
[0037] After a lapse of 60 minutes from the start of the feeding of
hydrogen gas, the feeding of hydrogen gas was stopped, and the
inner cylinder was cooled.
[0038] After cooling, when the mixture slurry in the inner cylinder
was filtered and the recovered cobalt powder was observed with an
electron microscope (SEM), it was verified that fine cobalt powder
was produced as shown in FIG. 2.
[0039] Further, the amount of precipitated cobalt obtained by
deducting the amount of seed crystals from the amount of cobalt
that was able to be recovered was divided by the amount of cobalt
contained in the original solution to determine the yield of the
cobalt powder produced by the reaction, that is, by reduction,
which was found to be 72%.
Comparative Example 1
[0040] An original solution containing cobalt was prepared under
the same conditions and in the same manner as in Example 1 above. A
mixture slurry according to Comparative Example 1 was prepared by
adding, to the original solution, cobalt powder as seed crystals in
an amount of 75 g which is 1.0 times the amount of cobalt in the
original solution and adjusting the total volume of the solution to
1000 ml. Next, an inner cylinder of an autoclave was charged with
the mixture slurry; the mixture slurry was then heated to
185.degree. C. with stirring; hydrogen gas was blown into the
mixture slurry while keeping the temperature; and hydrogen gas was
fed so as to maintain the pressure in the inner cylinder of the
autoclave at 3.5 MPa.
[0041] After a lapse of 60 minutes from the start of the feeding of
hydrogen gas, the feeding of hydrogen gas was stopped, and the
inner cylinder was cooled.
[0042] After cooling, when the solution in the inner cylinder was
filtered, fine cobalt powder was found to be produced.
[0043] However, the yield of the cobalt powder produced by the
reaction was only 36%, and high efficiency as in Example 1 of the
present invention was not obtained.
* * * * *