U.S. patent application number 17/290677 was filed with the patent office on 2022-01-13 for method for manufacturing needle-shaped or rod-shaped porous iron powder and needle-shaped or rod-shaped porous iron powder manufactured thereby.
The applicant listed for this patent is POSCO, RESEARCH INSTITUTE OF INDUSTRIAL SCIENCE & TECHNOLOGY. Invention is credited to Hyung-Sub EOM, Gil-Soo HAN, Jin-Gyun PARK.
Application Number | 20220008992 17/290677 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-13 |
United States Patent
Application |
20220008992 |
Kind Code |
A1 |
HAN; Gil-Soo ; et
al. |
January 13, 2022 |
METHOD FOR MANUFACTURING NEEDLE-SHAPED OR ROD-SHAPED POROUS IRON
POWDER AND NEEDLE-SHAPED OR ROD-SHAPED POROUS IRON POWDER
MANUFACTURED THEREBY
Abstract
The present invention relates to a method for manufacturing a
needle-shaped or rod-shaped porous iron powder. Specifically, the
present invention provides a method for manufacturing a
needle-shaped or rod-shaped porous iron and a needle-shaped or
rod-shaped porous iron powder manufactured thereby, the method
comprising the steps of: preparing a ferrous chloride dehydrate by
concentrating a ferrous chloride aqueous solution; solid-liquid
separating the ferrous dichloride to prepare ferrous chloride
dehydrate powder; oxidizing the ferrous chloride dehydrate powder;
and reducing the oxidized ferrous chloride powder.
Inventors: |
HAN; Gil-Soo; (Gangneung-si,
Gangwon-do, KR) ; EOM; Hyung-Sub; (Pohang-si,
Gyeongsangbuk-do, KR) ; PARK; Jin-Gyun; (Pohang-si,
Gyeongsangbuk-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
POSCO
RESEARCH INSTITUTE OF INDUSTRIAL SCIENCE & TECHNOLOGY |
Pohang-si, Gyeongsangbuk-do
Pohang-Si, Gyeongsangbuk-do |
|
KR
KR |
|
|
Appl. No.: |
17/290677 |
Filed: |
November 4, 2019 |
PCT Filed: |
November 4, 2019 |
PCT NO: |
PCT/KR2019/014795 |
371 Date: |
April 30, 2021 |
International
Class: |
B22F 9/24 20060101
B22F009/24; B22F 1/00 20060101 B22F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 5, 2018 |
KR |
10-2018-0134325 |
Claims
1. A method for manufacturing a needle-shaped or rod-shaped porous
iron powder, the method comprising: concentrating a ferrous
chloride aqueous solution to prepare a ferrous chloride dihydrate;
subjecting the ferrous chloride dihydrate to a solid-liquid
separation to prepare a ferrous chloride dihydrate powder;
oxidizing the ferrous chloride dihydrate powder; and reducing the
oxidized ferrous chloride dehydrate powder.
2. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 1, wherein the ferrous chloride aqueous
solution has a concentration of 20 to 625 g/L.
3. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 1, wherein the concentrating of the
ferrous chloride aqueous solution is carried out by evaporative
concentration at a temperature of 72 to 125.degree. C.
4. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 1, wherein the oxidizing of the ferrous
chloride dihydrate powder is carried out by calcination at a
temperature of 200 to 1300.degree. C. in an oxygen atmosphere.
5. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 1, wherein the reducing of the oxidized
ferrous chloride dihydrate powder is carried out at a temperature
of 400 to 1300.degree. C. under a reducing atmosphere.
6. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 5, wherein the reducing atmosphere is
an atmosphere of hydrogen, carbon monoxide, or a mixed gas
thereof.
7. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 6, wherein the reducing of the oxidized
ferrous chloride dihydrate powder is carried out at a temperature
of 600 to 800.degree. C. in the case of the hydrogen
atmosphere.
8. The method for manufacturing a needle-shaped or rod-shaped
porous iron powder of claim 6, wherein the reducing of the oxidized
ferrous chloride dihydrate powder is carried out at a temperature
of 700 to 1000.degree. C. in the case of the carbon monoxide
atmosphere.
9. A needle-shaped or rod-shaped porous iron powder manufactured by
the method of claim 1.
10. The needle-shaped or rod-shaped porous iron powder of claim 9,
wherein the iron powder has a specific surface of 0.3 to 3
m.sup.2/g.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a method for manufacturing
a needle-shaped or rod-shaped porous iron powder and a
needle-shaped or rod-shaped porous iron powder manufactured
thereby. More particularly, the present disclosure relates to a
method for manufacturing a needle-shaped or rod-shaped porous iron
powder using a ferrous chloride aqueous solution and a
needle-shaped or rod-shaped porous iron powder manufactured
thereby.
BACKGROUND ART
[0002] Conventionally, as a method for manufacturing iron powder,
there is a sponge-iron process and a water-atomizing process. The
sponge-iron process is a process of reducing iron oxide to produce
a porous iron powder and the water-atomizing process is a process
of using a high-pressure water jet to atomize molten iron, and the
iron powder manufactured therefrom is not a porous powder but a
dense powder. In addition, most of the powders manufactured
therefrom have an angled cube shape, a spherical shape, or a
non-uniform shape.
[0003] For the iron oxide used in the sponge-iron process, an iron
ore, a powder produced during an iron manufacturing process, iron
oxide manufactured using a post-pickling solution produced after
surface pickling during an iron plate manufacturing process, or the
like, may be used as a raw material, and since a porous iron powder
manufactured by the sponge-iron process has a large specific
surface area, high reactivity, and strong reducibility, the porous
iron powder may be used in self-lubricating bearing materials;
materials for purifying soil, groundwater, or industrial wastewater
(such as a catalyst and reducing agent); welding rod coating
materials; pocket warmer materials; a deoxidizer; a raw materials
for preparing iron compounds; an extractant for cementation; and
the like.
[0004] Meanwhile, U.S. Patent Publication No. 2016-0096739 uses a
method for manufacturing an iron powder by a ferrous chloride
aqueous solution, but when a method for manufacturing a
needle-shaped or rod-shaped porous iron powder from the ferrous
chloride aqueous solution is developed, it is expected that the
method will be used more usefully in the field of using an iron
powder.
DISCLOSURE
Technical Problem
[0005] An aspect of the present disclosure is to provide a method
for manufacturing an iron powder having both a needle shape or rod
shape characteristic and a porous characteristic.
[0006] Another aspect of the present disclosure is to provide an
iron powder manufactured by the manufacturing method of the present
disclosure.
Technical Solution
[0007] According to an aspect of the present disclosure, a method
for manufacturing a needle-shaped or rod-shaped porous iron powder
includes: concentrating a ferrous chloride aqueous solution to
prepare a ferrous chloride dihydrate; subjecting the ferrous
chloride dihydrate to a solid-liquid separation to prepare a
ferrous chloride dihydrate powder; oxidizing the ferrous chloride
dihydrate powder; and reducing the oxidized ferrous chloride
dihydrate.
[0008] According to another aspect of the present disclosure, a
needle-shaped or rod-shaped porous iron powder manufactured by the
manufacturing method is provided.
Advantageous Effects
[0009] According to the process of the present disclosure, an iron
powder may be mass-produced from an iron chloride aqueous solution,
and the thus-manufactured iron powder has a porous needle shape or
rod shape and may be used in the conventional porous iron powder
application fields, of course, and also may obtain filling rate
improvement, workability improvement, physical property
improvement, and the like based on the characteristics of the
rod-shaped powder.
DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a schematic flow chart of a method for
manufacturing a needle-shaped or rod-shaped porous iron powder of
the present disclosure.
[0011] FIG. 2 is an image of ferrous chloride dihydrate and ferrous
chloride tetrahydrate crystals shown in the concentration of a
ferrous chloride aqueous solution according to an exemplary
embodiment of the present disclosure, taken by SEM.
[0012] FIG. 3 is an image of an iron oxide powder obtained after
subjecting ferrous chloride dihydrate obtained by the concentration
of the ferrous chloride aqueous solution according to an exemplary
embodiment of the present disclosure to a calcination process,
taken by SEM.
[0013] FIG. 4 is an image of a reduced iron powder obtained after
subjecting an iron oxide powder according to an exemplary
embodiment of the present disclosure to a reduction reaction, taken
by SEM.
BEST MODE FOR INVENTION
[0014] Hereinafter, preferred embodiments of the present disclosure
will now be described in detail with reference to the accompanying
drawings. However, the embodiments of the present disclosure may be
modified in many different forms and the scope of the present
disclosure should not be limited to the embodiments set forth
herein.
[0015] The present disclosure provides a method for manufacturing
an iron powder having both a needle shape or rod shape
characteristic and a porous characteristic and iron powder
manufactured by the manufacturing method.
[0016] Specifically, the method for manufacturing a needle-shaped
or rod-shaped porous iron powder of the present disclosure provides
a method for manufacturing a needle-shaped or rod-shaped porous
iron powder including: concentrating a ferrous chloride aqueous
solution to prepare a ferrous chloride dihydrate; subjecting the
ferrous chloride dihydrate to a solid-liquid separation to prepare
a ferrous chloride dihydrate powder; oxidizing the ferrous chloride
dihydrate powder; and reducing the oxidized ferrous chloride
dihydrate.
[0017] A raw material of the ferrous chloride aqueous solution may
be a post-solution produced after a pickling process for removing
oxides on a surface during an iron plate manufacturing process, a
post-solution produced during other processes, or an aqueous
solution in which iron is dissolved in hydrochloric acid, and it is
preferred that the ferrous chloride aqueous solution may not be a
saturated or supersaturated aqueous solution.
[0018] A concentration of the ferrous chloride aqueous solution is
20 to 625 g/L, preferably 250 to 600 g/L. When the concentration is
less than 20 g/L, an amount of ferrous chloride in the aqueous
solution is low, energy to evaporate moisture during concentration
is excessively consumed and an amount of precipitated ferrous
chloride dihydrate is small, and when the concentration is more
than 625 g/L, the ferrous chloride aqueous solution is saturated or
supersaturated to cause precipitation during transport.
[0019] The step of preparing ferrous chloride dihydrate is to
concentrate the ferrous chloride aqueous solution to precipitate
supersaturated ferrous chloride dihydrate, and the concentration at
this time may be carried out by evaporative concentration.
[0020] Meanwhile, in the solid-liquid separation carried out in the
step of preparing a ferrous chloride dihydrate powder, the
precipitated ferrous chloride dihydrate may be separated, for
example, using a centrifuge, but the present disclosure is not
limited thereto, and the solid-liquid separation may be carried out
by any method which may be used for the solid-liquid separation in
the art, such as filtration.
[0021] When the step of preparing ferrous chloride dihydrate is
carried out by evaporative concentration, a temperature in a
concentration process should be adjusted, and it is preferred that
the evaporative concentration herein is carried out at a
temperature of, for example, 72 to 125.degree. C., preferably 75 to
95.degree. C. When the evaporative concentration is carried out at
a temperature of lower than 72.degree. C., ferrous chloride
tetrahydrate may be precipitated and the ferrous chloride
tetrahydrate is precipitated in the form of an angled polyhedron,
and at a temperature of higher than 125.degree. C., iron chloride
monohydrate is produced and energy is excessively consumed. An
image of the ferrous chloride tetrahydrate precipitated in the form
of an angled polyhedron, taken by SEM is shown in FIG. 2.
[0022] The step of oxidizing a ferrous chloride dihydrate powder
maybe carried out by a calcination process in which a pyrolysis
reaction is carried out under an oxygen atmosphere. In the
calcination process, a reaction of ferrous chloride dihydrate with
oxygen is as follows:
2(FeCl.sub.2H.sub.2O)+1/2O.sub.2.fwdarw.Fe.sub.2O.sub.3+4HCl
(g)
[0023] Here, an oxide of Fe.sub.3O.sub.4 or FeO may be rarely
produced as well as Fe.sub.2O.sub.3 by the reaction above.
[0024] In addition, although the calcination process is not
limited, a reaction furnace such as a fluidized furnace, a rotary
kiln, a belt furnace, and a drop tube furnace maybe used, and it is
necessary to minimize crushing of powder by an action of external
force on the powder during the reaction to maintain the form of a
rod shape.
[0025] Furthermore, the reaction of the calcination process may be
carried out at a temperature of 200 to 1300.degree. C. At a
temperature of lower than 200.degree. C., iron oxide is not
produced, and at a temperature higher than 1300.degree. C., iron
oxide sintering occurs so that it is difficult to obtain iron oxide
having a desired shape. The reaction may preferably be carried out
at a temperature of 500 to 800.degree. C.
[0026] Classification maybe carried out for dividing the shape of
iron oxide produced by the calcination process. Furthermore,
hydrochloric acid produced in the process may be wet-collected to
prepare a hydrochloric acid aqueous solution, which may be used in
preparation of the ferrous chloride aqueous solution.
[0027] The step of reducing the oxidized ferrous chloride dihydrate
maybe carried out by subjecting the oxidized ferrous chloride
dihydrate to a reduction reaction under a high temperature reducing
atmosphere. Here, the reducing atmosphere may be, for example, an
atmosphere of hydrogen, carbon monoxide, or a mixed gas thereof,
and a compound which may produce hydrogen, carbon monoxide, or a
mixed gas thereof by a reaction such as decomposition may be used
as a reducing agent. The reduction reaction is, for example, as
follows:
Fe.sub.2O.sub.3+3H.sub.2(g) or 3CO(g).fwdarw.2Fe+3H.sub.2O(g) or
3CO.sub.2(g)
[0028] Here, an oxide of Fe.sub.3O.sub.4 or FeO which is rarely
produced in the oxidation step undergoes a reduction reaction by
the following reaction:
FeO+H.sub.2(g) or CO(g).fwdarw.Fe+H.sub.2O(g) or CO.sub.2(g)
Fe.sub.3O.sub.4+4H.sub.2(g) or 4CO(g).fwdarw.3Fe+4H.sub.2O(g) or
4CO.sub.2(g)
[0029] In addition, though the reduction process is not limited, a
reaction furnace such as a fluidized furnace, a rotary kiln, a belt
furnace, and a drop tube furnace may be used, and it is necessary
to minimize crushing of powder by an action of external force on
the powder during the reaction to maintain the form of a rod
shape.
[0030] Furthermore, the reduction reaction may be carried out at a
temperature of 400 to 1300.degree. C. It is because at a
temperature less than 400.degree. C., a reaction rate is low so
that productivity is decreased, and at a temperature higher than
1300.degree. C., sintering of reduced iron produced may excessively
occur or a reduced iron microstructure is coarsened so that a
porous structure disappears. When the reducing atmosphere is a
hydrogen atmosphere, the reduction reaction may preferably be
carried out at a temperature of 600 to 800.degree. C., and when the
reducing atmosphere is a carbon monoxide atmosphere, the reduction
reaction may preferably be carried out at a temperature of 700 to
1000.degree. C.
[0031] Classification maybe carried out for dividing the shape of
iron oxide produced by the reduction reaction. Furthermore, since
the prepared reduced iron may have good reactivity to cause
reoxidation, a powder should be collected under an inert
atmosphere.
[0032] The needle-shaped or rod-shaped porous iron powder
manufactured by the manufacturing method of the present disclosure
has a specific surface area of 0.3 to 3 m.sup.2/g, preferably 0.5
to 2.5 m.sup.2/g. When the specific surface area of the iron powder
is less than 0.3 m.sup.2/g, reactivity is low, and when the
specific surface area is more than 3 m.sup.2/g, oxidation or
ignition easily occurs in the atmospheric state so that handling is
difficult in the process.
[0033] Hereinafter, the present disclosure will be described in
detail through the specific examples. The following example is only
illustrative for assisting in the understanding of the present
disclosure, and the scope of the present disclosure is not limited
thereto.
[Mode for Invention]
EXAMPLES
[0034] A ferrous chloride (FeCl.sub.2) aqueous solution produced in
a nickel hydrometallurgical process was used to manufacture a
needle-shaped or rod-shaped iron powder. An exemplary process is
shown in FIG. 1, and a specific process is as follows.
[0035] A ferrous chloride aqueous solution (concentration: 220 g/L)
was concentrated to precipitate ferrous chloride dihydrate
(FeCl.sub.2.2H.sub.2O). The precipitated ferrous chloride dihydrate
was subjected to a solid-liquid separation by a centrifugation
method to separate a ferrous chloride dihydrate powder. Here,
aqueous solution concentration was carried out at a temperature of
80.degree. C.
[0036] An image of a ferrous chloride dihydrate crystal prepared in
this step, taken by SEM is shown in FIG. 2.
[0037] Next, the ferrous chloride dihydrate powder was added to a
rotary kiln and calcined by a pyrolysis reaction under a high
temperature atmosphere including oxygen. Thus, needle-shaped or
rod-shaped iron oxide was manufactured therefrom.
[0038] The calcination process was carried out at 700.degree. C.
for 90 minutes, and classification was carried out for dividing a
shape of the needle-shaped or rod-shaped iron oxide produced. In
addition, an oxide of Fe.sub.3O.sub.4 or FeO may also be rarely
produced as well as Fe.sub.2O.sub.3. Meanwhile, HCl produced
together in the rotary kiln was collected by a scrubber and reused
in a nickel smelting process.
[0039] An image of oxidized iron powder produced by the above
process, taken by SEM is shown in FIG. 3.
[0040] Next, the needle-shaped or rod-shaped iron oxide was
injected with a mesh belt and a reduced iron powder was
manufactured by a reduction reaction in a high temperature gas
reducing atmosphere. Here, the gas reducing atmosphere was a
hydrogen or carbon monoxide atmosphere.
[0041] The reduction reaction was carried out at 750.degree. C. for
60 minutes and classification was carried out for dividing the
shape of needle-shaped or rod-shaped iron oxide produced to divide
the powder into a needle-shaped or rod-shaped reduced iron powder
and a fine reduced iron powder.
[0042] The produced needle-shaped or rod-shaped reduced powder was
a powder having a length of about 500 .mu.m and an aspect ratio of
about 5 and had a specific surface area of about 2.3 m.sup.2/g.
Here, since the prepared reduced iron may have good reactivity to
cause reoxidation, the powder should be collected under an inert
atmosphere.
[0043] An image of reduced iron powder produced by the above
process, taken by SEM is shown in FIG. 4.
[0044] Hereinabove, the exemplary embodiments of the present
disclosure were described in detail, however, the scope of a right
of the present disclosure is not limited thereto, and it is
apparent to a person skilled in the art that various modifications
and changes are possible within the scope not departing from the
technical idea of the present disclosure.
* * * * *