BLAST-FURNACE BLOWING COAL AND METHOD FOR PRODUCING
SAME
TECHNICAL FIELD
5 [OOOl]
The present invention relates to blast-furnace injecting coal and a
method for producing the same.
BACKGROUND ART
10 [0002]
Blast furnaces have been configured such that pig iron can be produced
from iron ore by charging iron ore, calcium oxide and coke starting materials
from the top to the interior of the 'blast-furnace body and injecting in hot wind
and blast-furnace injecting pulverized coal as an auxiliary fuel from a tuyere on
15 the bottom side of the side part of the blast-furnace body.
[0003]
In order to stably operate the above blast furnaces, it is necessary to
suppress adhesion of the blast-furnace-injecting-coal ash or blockages caused
by the blast-furnace-injecting-coal ash along the path of the blast-furnace
20 injecting coal to the interior of the blast-furnace body.
[0004]
For example, it has been proposed to improve combustibility of
blast-furnace injecting coal by adding a CaO-based flux such as calcium oxide
or serpentinite to pulverized coal of which the melting point of the pulverized
.25 coal ash is less than 1300°C, thereby adjusting the melting pointof the ash in
the pulverized coal to not less than 1300°C, and then injecting only the
pulverized coal of which the melting point of the pulverized coal ash is not less
than 1300°C into the interior from the tuyere of the blast-furnace body (for
example, refer to.~atenDt ocument 1 below).
30 [0005] .
Additionally, for example, a blast-furnace pulverized coal injecting
operating method has been proposed, whereby permeability can be improved
even in operations where the amount of injected pulverized coal is extremely
large by regulating the amount of enriched oxygen or adjusting the composition,
35 particle size, or the like of the pulverized coal to make it poorly combustible to
reduce the maximum temperature reached in the raceway (for example, refer to
Patent Document 2 below).
I P 8 DELHI $ 3 - 0 2 - 2 0 1 5 P E i : 4 7 '
PRIOR ART DOCUMENT
Patent Literature
[0006]
Patent Document 1 : Japanese Unexamined Patent Application
5 Publication No. H05- 156330A
(for example, refer to paragraphs [0014] - [0023] of Specification, FIG. 1, and
the like)
Patent Document 2: Japanese Unexamined Patent Application
Publication No. H11- 152508A
10
SUMMARY OF INVENTION
Technical Problem
[0007]
However, the pulverized coal (blast-furnace injecting coal) described in
15 Patent Document 1 causes an increase in running cost because only the
pulverized coal of which the ash melting point has been adjusted to not less'than
1300°C by intentionally adding the flux to pulverized coal is used.
[0008]
Furthermore, the blast-furnace pulverized coal injecting operating
20 method described in Patent Document 2 ends up causing an increase in running
cost because the amount of injected pulverized coal is extremely large and the
composition and particle size of the pulverized coal must be intentionally
adjusted.
[0009]
2 5 Due to such facts, the present invention was devised to solve the
problems described above, and an object thereof is to provide blast-furnace
injecting coal which is low in cost and capable of suppressing adhesion of
blast-furnace-injecting-coal ash and blockages caused by the
blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
30 coal to the interior of the blast-furnace body, and a method for producing the
same.
Solution to Problem
[OO lo]
3 5 The blast-furnace injecting coal according to a first invention which
solves the above problems is blast-furnace injecting coal which is injected
through a tuyere into an interior of a blast-furnace body of a blast furnace; a
composition and a melting point of coal ash being analyzed in advance and a
PP8 DELHI 13-86-281-5 16 14.7
composition of iron and steel slag produced by an iron and steel production step
being analyzed in advance; the iron and steel slag containing more calcium
oxide than the coal ash does; and the coal and the iron and steel slag being
mixed, on the basis of the composition and melting point of the coal ash and the
composition of the iron and steel slag, and in a manner such that a content of
calcium oxide contained in a quaternary system phase diagram including silicon
dioxide, magnesium oxide, aluminum oxide and calcium oxide, which are
principal components of the coal ash and the iron and steel slag, causes the
melting point of the ash to be 1400°C or higher.
[OO 111
The blast-furnace injecting coal according to a second invention which
solves the above problems is the blast-furnace injecting coal according to the
first invention, wherein the coal has been pulverized to an average particle size
of not greater than 1 mm, and the iron and steel slag has been pulverized to a
particle size of 20 pm to 100 pm.
[OO 121
The blast-furnace injecting coal according to a third invention which
solves the above problems is the blast-furnace injecting coal according to the
first invention, wherein the blast-furnace injecting coal is formed by adding a
binder and water to a mixture of the coal and the iron and steel slag and
molding into briquettes.
[00 131
The blast-furnace injecting coal according to a fourth invention which
solves the above problems is the blast-furnace injecting coal according to the
second invention, wherein the blast-furnace injecting coal is formed by adding a
binder and water to a mixture of the coal and the iron and steel slag and
molding into briquettes.
[00 141
The method for producing blast-furnace injecting coal according to a
fifth invention which solves the above problems is a method for producing
blast-furnace injecting coal which' produces blast-furnace injecting coal to be
injected through a tuyere into an interior of a blast-furnace body of a blast
furnace, the method comprising performing: an analysis step of analyzing a
composition and a melting point of coal ash and analyzing a composition of an
iron and steel slag produced by an iron and steel production step; and a mixing
step, in which the iron and steel slag contains more calcium oxide than the coal
ash does; and the coal and the iron and steel slag are mixed on the basis of the
composition and melting point of the coal ash and the composition of the iron
1 DELHH, 1.3-02-2615 1%- 447'
and steel slag, and in a manner such that a content of calcium oxide contained in
a quaternary system phase diagram including silicon dioxide, magnesium oxide,
aluminum oxide and calcium oxide, which are principal components of the coal
ash and the iron and steel slag, causes the melting point of the ash to be 1400°C
5 or higher.
[00 151
The method for producing blast-furnace injecting coal according to a
sixth invention which solves the above problems is the method for producing
blast-furnace injecting coal according to the fifth invention, wherein the coal
10 has been pulverized to an average particle size of not greater than 1 mm, and the
iron and steel slag has been pulverized to a particle size of 20 pm to 100 pm. '
' [0016]
The method for producing blast-furnace injecting coal according to a
seventh invention which solves the above problems is the method for producing
15 blast-furnace injecting coal according to the sixth invention, the method further
comprising performing: in the mixing step, further adding a binder and water,
and mixing with the coal and the iron and steel slag; and a molding step in
which the mixture obtained in the mixing step is molded into briquettes.
20 Advantageous Effects of Invention '.
[00 171
According to the blast-furnace injecting coal according to the present
invention, by mixing coal and iron and steel slag such that the calcium oxide
content causes the melting point of the ash to be 1400°C or higher, the melting
25 point of the ash becomes 100°C.to 150°C higher than the temperature of the hot
wind injected into the interior from the tuyere of the blast-furnace body or even
higher, and the iron and steel slag is discharged in the iron and steel production
process. As a result, the iron and steel slag can be effectively utilized, and it
is unnecessary to separately provide a calcium oxide source that is mixed with
30 the coal, and adhesion of the blast-furnace-injecting-coal ash and blockages
caused by the blast-furnace-injecting-coal ash along the path of the
blast-furnace injecting coal to the interior of the blast-furnace body can be
suppressed at low cost.
[OO 181
35 Additionally, according to the method for producing blast-furnace
injecting coal according to the present invention, the blast-furnace injecting
coal described above can be produced easily and at low cost.
Brief Description of Drawings
[00 191
FIG. 1 is a flowchart illustrating the procedure of a first embodiment of
the method for producing blast-furnace injecting coal according to the present
5 invention.
FIG. 2 is a flowchart illustrating the procedure of a second embodiment
of the method for producing blast-furnace injecting coal according to the
present invention.
FIG. 3 is a quaternary system phase diagram of Si02-Ca0-Mg0-20%
10 A1203 for blast-furnace injecting coal.
Description of Embodiments
[0020]
Embodiments of the blast-furnace injecting coal and the method for
15 producing the same according to the present invention will be described based
on drawings, but the present invention is not limited only to the embodiments
described below based on drawings.
[002 11
[First Embodiment]
20 A first embodiment of the blast-furnace injecting coal and the method for
producing the same according to the present invention will be described based
on FIG. 1.
[0022]
In the blast-furnace injecting coal according to this embodiment, the
25 composition and melting point of the coal ash are analyzed in advance and the
composition of the blast-furnace slag discharged from a blast furnace is
analyzed in advance, and the blast-furnace slag contains more calcium oxide
than the coal ash does, and the coal and the blast-furnace slag are mixed based
on the composition and melting point of the coal ash and the composition of the
30 blast-furnace slag, and in a manner such that the content of calcium oxide
contained in a quaternary system phase diagram including silicon dioxide,
magnesium oxide, aluminum oxide and calcium oxide, which are the principal
components of the coal ash and the blast-furnace slag, causes the melting point
of the ash to be 1400°C or higher, which is higher than the temperature of the
35 hot wind (1200°C) injected into the interior from the tuyere on the bottom side
of the side part of the blast-furnace body of the blast furnace.
[0023]
I P O DELHI 1 3 - O h . - L O X 5 16147
The blast-furnace injecting coal 13 according to this.embodiment may be
easily produced by analyzing the composition of the coal 11, which is low-grade
coal such as sub-bituminous coal or lignite, and the melting point of the ash
thereof (analysis step Sll-1), and analyzing the composition of the
5 blast-furnace slag 12 discharged from the blast furnace (analysis step S11-2),
and then finely pulverizing the coal 11 (fine pulverization step S 12-1) and
finely pulverizing the blast-furnace slag 12 (fine pulverization step S 12-2), and
then mixing the coal 11 and the blast-furnace slag 12 (mixing step S 13), and
pulverizing the mixture (pulverization step S14) as shown in FIG. 1.
10 Furthermore, the pulverization step S14 is preferably performed immediately
before injecting into the blast furnace.
[0024]
The calcium oxide content of the blast-furnace slag 12 is, for example,
41.7 wt.%, and is greater than the calcium oxide content of the ash from the
15 c o a l l l .
[0025]
In the fine pulverization step S 12- 1, the coal 11 is finely pulverized to an
average particle size of not greater than 1 mm. This is because, if the coal 11
has an average particle size greater than 1 mm, it is difficult to homogenize
20 when mixed with the blast-furnace slag 12 in the mixing step S13.
[0026]
In the fine pulverization step S12-2, the blast-furnace slag 12 is finely
pulverized to a particle size of 20 pm to 100 pm. This is because, if the
blast-furnace slag 12 has a particle size smaller than 20 pm, when injected into
25 the interior of the blast-furnace body, it passes through the interior of the
blast-furnace body while carried on the gas stream, and ends up being
discharged without combusting. If the blast-furnace slag 12 has a particle size .
greater than 100 pm, it is difficult to homogenize when mixed with the coal 11
in the mixing step S 13.
30 [0027]
In the blast-furnace injecting coal 13 produced by the production method
according to this embodiment, by mixing the coal 11. and the blast-furnace slag
12 such that the calcium oxide content causes the melting point of the ash to be
1400°C or higher, the melting point of the ash becomes 100°C to 150°C higher
35 than the temperature of the hot wind injected into the interior from the tuyere of
the blast-furnace body or even higher, and the ash from the.blast-furnace
injecting coal 13 (blast-furnace-injecting-coal ash) is not melted by .the hot
wind, and as a result, adhesion of the blast-furnace-injecting-coal ash or
PPlJt E E L H I 1 1 - Q Z E , - E ~ 1 5P &'.&.T
blockages caused by the blast-furnace-injecting-coal ash along the path of the
blast-furnace injecting coal to the interior of the blast-furnace body can be
suppressed. Furthermore, because the blast-furnace slag 12 is discharged in
the iron and steel production process of the blast furnace, the blast-furnace slag ~ 5 12 can be effectively utilized, and it is unnecessary to separately provide a
calcium oxide source mixed with the coal 11, and thus cost is low.
[0028]
For this reason, with the blast-furnace injecting coal 13 according to this
embodiment, simply by causing the coal 11 to contain the blast-furnace slag 12
10 discharged from the blast furnace, which contains more calcium oxide than the
ash from the coal 11, even without additionally adding flux such as calcium
oxide or serpentinite, it is possible to increase the melting point of the ash from
the blast-furnace injecting coal 13 (blast-furnace-injecting-coal ash) to 1400°C
or higher even though the melting point of the ash from the coal 11 is a low
15 temperature of 1100°C to 1300°C, and the ash from the blast-furnace injecting
coal 13 (blast-furnace-injecting-coal ash) is not melted even by the hot wind.
As a result, adhesion of the blast-furnace-injecting-coal ash or blockages caused
by the blast-furnace-injecting-coal ash along the path of the blast-furnace
injecting coal to the interior of the blast-furnace body can be suppressed.
20 [0029]
Therefore, according to this embodiment, adhesion of the
blast-furnace-injecting-coal ash or blockages caused by the
blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
coal to the interior of the blast-furnace body can be suppressed at low cost.
25 [0030]
Furthermore, in the blast-furnace injecting coal and the method for
producing the same according to this embodiment, the case where blast-furnace
slag 12 having a greater calcium oxide content than the ash composition of the
I coal is used as the iron and steel slag mixed with the coal 11 has been described,
I 30 but iron and steel slag having a greater calcium oxide content than the ash
I composition of the coal produced in the iron and steel production process, for
example, converter slag discharged by converter equipment (for example,
having calcium oxide content of about 45.8 wt.%), or, for example, reducing
slag produced by dissolution/reducing smelting of iron scrap (for example,
35 having calcium oxide content of about 55.1 wt.%) may also be used.
[003 11
[Second Embodiment]
A second embodiment of the blast-furnace injecting coal and the method
for producing the same according to the present invention will be described
based on FIG. 2. Note that, for parts that are the same as the above
embodiment, the same reference numerals as those used in the description of the
5 above embodiment are used, and therefore duplicate descriptions of the above
embodiment are omitted.
[0032]
In the blast-furnace injecting coal according to this embodiment, the
composition and melting point of the coal ash are analyzed in advance and the
10 composition of the blast-furnace slag discharged from the blast furnace is
analyzed in advance, and the blast-furnace slag contains more calcium oxide
than the coal ash does, and the coal and the blast-furnace slag are mixed, on the
basis of the composition and melting point of the coal ash and the composition
of the blast-furnace slag, and in a manner such that the content of calcium oxide
15 contained in a quaternary system phase diagram including silicon dioxide,
magnesium oxide, aluminum oxide and calcium oxide, which are the principal
components of the coal ash and the blast-furnace slag, causes the melting point
of the ash to be 1400°C or higher, which is higher than the temperature of the
hot wind (1200°C) injected into the interior from the tuyere un the bottoln side
20 of the side part of the blast-furnace body of the blast furnace, and a binder and
water are further mixed in.
[0033]
The blast-furnace injecting coal 23 according to this embodiment may be
easily produced by analyzing the composition of the coal 11, which is the
25 low-grade coal described above, and the melting point of the ash thereof in the
same manner as in the above embodiment (analysis step S 11 - 1), and analyzing
the composition of the blast-furnace slag 12 discharged from the blast furnace
in the same manner as in the above embodiment (analysis step S 11 -2), and then
finely pulverizing the coal 11 in the same manner as in the above embodiment
30 (fine pulverization step S12-1) and finely pulverizing the blast-furnace slag 12
in the same manner as in the above embodiment (fine pulverization step S 12-2),
and then mixing the coal 11 and the blast-furnace slag 12 with a binder 24 and
water 25 (mixing step S 13), molding the mixture into briquettes (molding step
S25), and pulverizing the briquette-shaped molded articles (pulverization step
35 S14) as shown in FIG. 2. Furthermore, the pulverization step S14 is preferably
performed immediately before injecting into the blast furnace.
[0034]
In short, in this embodiment, by molding a mixture obtained by mixing
the coal 11 and the blast-furnace. slag 12 with the binder 24 and the water 25 in
the mixing step S 13 into briquettes in the molding step S25, blast-furnace
injecting coal 23 is obtained by homogenizing the silicon dioxide, magnesium
5 oxide, aluminum oxide and calcium oxide which are the principal components
of the ash from the coal 11 and the blast-furnace slag 12, and pulverizing in the
pulverization step S 14.
[0035]
The calcium oxide content of the blast-furnace slag 12 is, for example,
10 41.7 wt.%, and is greater than the calcium oxide content of the ash from the
coal 11.
[0036]
As the binder 24, a binder that enables molding of the mixture into
briquettes in the molding step S25, that hardly affects the melting point of the
15 ash from the blast-furnace injecting coal 23 (blast-furnace-injecting-coal ash),
and that is completely combusted in the blast furnace may be used, examples of
which include cornstarch, molasses, asphalt and the like.
[0037]
The mixed amount of the binder 24 is an amount that enables molding of
20 the mixture of the coal 11 and the blast-furnace slag 12 into pellets, for example,
an amount in a range of 1 wt.% to 5 wt.% with respect to the mixture of the coal
11 and the blast-furnace slag 12. This is because, if the mixed amount of
binder 24 is less than 1 wt.%, the mixture of the coal 11 and the blast-furnace
slag 12 cannot be molded into briquettes, and if the mixed amount of binder 24
25 is greater than 5 wt.%, running cost increases. The mixed amount of water 25
is an amount that enables molding of the mixture of the coal 11 and the
blast-furnace slag 12 into pellets, for example, an amount in a range of 2 wt.%
to 8 wt.% with respect to the,mixture of the coal 11 and the blast-furnace slag
12. This is because, if the mixed amount of water 25 is less than 2 wt.%, the
30 mixture of the coal 11 and the blast-furnace slag 12 cannot be molded into
briquettes, and if the mixed amount of water 25 is greater than 8 wt.%, excess
energy ends up being consumed in the pulverization and drying steps in the '
blast furnace due to evaporation of moisture.
[0038]
3 5 In short, in this embodiment, because a binder 24 and water 25 are added
to and further mixed with the mixture of the coal 11 and the blast-furnace slag
12, by molding that mixture into pellets in the molding step S25, the silicon
dioxide, magnesium oxide, aluminum pxi*, calcium oxide, and the like which
1 ~D0 ,15- 02- LOX% XG a'f
are the principal components are homogenized, and ease of handling (transport,
storage, and the like) is improved.
[0039]
In the blast-furnace injecting coal 23 produced by the production method
5 according to this embodiment, similar to the embodiment described above, by
mixing the coal 11 and the blast-furnace slag 12 such that the calcium oxide
content causes the melting point of the ash to be 1400°C or higher', the melting
point of the ash becomes 100°C to'150°C higher than the temperature of the hot
wind injected into the interior from the tuyere of the blast-furnace body or even
10 higher, and the ash from the blast-furnace injecting coal 23
(blast-furnace-injecting-coal ash) is not melted by the hot wind, and as a result,
adhesion.of the blast-furnace-injecting-coal ash or blockages caused by the
blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
coal to the interior of the blast-furnace body can be suppressed. Furthermore,
15 because the blast-furnace slag 12 is discharged in the iron and steel production
process of the blast furnace, the blast-furnace slag 12 can be effectively utilized,
and it is unnecessary to separately provide a calcium oxide source mixed with
the coal 11, and thus cost is low.
[0040]
20 Because the mixture of the coal 11, the blast-furnace slag 12, the binder
24, and'the water 25 is molded into briquettes in the molding step S25 and then
pulverized in the pulverization step S 14, silicon dioxide, magnesium oxide,
aluminum oxide and calcium oxide are homogenized, and, more so than in the
above embodiment, blast-furnace injecting coal can be injected into the interior
25 from the tuyere on the bottom side of the side part of,the blast-furnace body
without further generating adhesion of the blast-furnace-injecting-coal ash or
blockages caused by the blast-furnace-injecting-coal ash along the path of the
blast-furnace injecting coal to the interior of the blast-furnace body.
[004 11
30 For this reason, with the blast-furnace injecting coal 23 according to this
embodiment, simply by causing the coal 11 to contain the blast-furnace slag 12
discharged from the blast furnace, which contains more calcium oxide than the
ash from the coal 11, even without additionally adding flux such as calcium
oxide or serpentinite, more so than in the. above embodiment, it is possible to
35 reliably increase the melting point of the ash from the blast-furnace injecting
coal 13 (blast-furnace-injecting-coal ash) to 1400°C or higher even though the
melting point of the ash from the coal 11 is a low temperature of 1100°C to
1300°C, and the ash from the blast-furnace injecting coal 23
PP'8 DELHG 1 3 - 0 2 . - B O P S l i G Z 4 T
(blast-furnace-injecting-coal ash) is not melted even by the hot wind. As a
result, adhesion of the blast-furnace-injecting-coal ash or blockages caused by
the blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
coal to the interior of the blast-furnace body can be suppressed.
5 [0042]
Therefore, according to this embodiment, adhesion of the
I blast-furnace-injecting-coal ash or blockages caused .by the
I blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
I coal to the interior of the blast-furnace body can be more reliably suppressed
10 than in the above embodiment, at low cost.
Examples
[0043]
Working examples for ascertaining the effect of the blast-furnace
15 injecting coal and the method for producing the same according to the present
invention will be described below, but the present invention is not limited only
to the working examples below which are described based on various data.
[0044]
Compositional. ana1,ysis (elemental analysis) of the ash from the coal
20 used in the method for producing blast-furnace injecting coal according to the
second embodiment described above was performed. This coal was modified
coal obtained by heat-treating sub-bituminous coal for 0.5 hours in an inert
atmosphere (for example, nitrogen gas) at 400°C. The ash content in the coal
was 7 wt.%. The results of compositional analysis of the coal ash (principal
25 components) are shown,in Table 1 below. Furthermore, from FIG. 3, which
illustrates a quaternary system phase diagram including silicon dioxide,
magnesium oxide, calcium ,oxide and aluminum oxide, it is clear that the
melting point of the coal ash is 1215"C, since the composition shown in Table I
below results in the position of point PI.
[0046]
Compositional analysis (elemental analysis) of the blast-furnace slag
[Table 11
used in the method for producing blast-furnace injecting coal according to the
SiOz (wt.%)
4 1
35 second embodiment described above was performed. The results of
I P 8 D E f HF 13- 0 2 --2015 %G '. 47
CaO (wt.%)
3 0
A1203 (wt.%)
2 2
MgO (wt.%)
7
1 compositional analysis of the blast-furnace slag (principal components) are
shown in Table 2 below.
[0047]
[Table 21
[0048]
In FIG. 3, because the calcium oxide content that results in an ash
melting point of 1400°C is 35 wt.% (position of point P2), it is clear that mixing
95 wt.% of the coal and 5 wt.% of the blast-furnace slag resulted in the ash
composition after mixing having a calcium oxide content of 35 wt.%, as shown
in Table 3 below, and an ash melting point of 1400°C. Furthermore, 3 wt.% of
cornstarch as a binder and 6 wt.% of water were added to the mixture of the coal
and the blast-furnace slag.
[0049]
[Table 31
15 [0050]
Thus, according to this working example, the composition of the coal ash
and the melting point of the ash are analyzed and the composition of the
blast-furnace slag is analyzed, and by using blast-furnace injecting coal in
which the coal and the blast-furnace slag are mixed such that the calcium oxide
20 content causes the melting point of the ash to be 1400°C based on these analysis
results, it is possible to raise the melting point of the ash above the temperature
of the hot wind injected into the interior from the tuyere on the bottom side of
the side part of the blast-furnace body of a blast furnace, and it is possible to
suppress adhesion of the blast-furnace-injecting-coal ash or blockages caused
25 by the blast-furnace-injecting-coal ash along the path of the blast-furnace
injecting coal to the interior of the blast-furnace body, at low cost.
[005 11
Furthermore, in the above description, a method for producing
blast-furnace injecting coal in which the mixed amounts of coal and
30 blast-furnace slag are determined using a quaternary system phase diagram
including Si02-Ca0-Mg0-20% A1203 was described, but this is because the ash
si02 (wt.%)
39
melting point is more dependent on the calcium oxide content than on the
content of silicon dioxide ma nesium o5iGe or aluminum oxide, and the mixed IQa DELHI, a . s - o r - r . d l 8 1s: q g
CaO (wt.%)
3 5
A1203 (wt.%)
18
MgO (wt.%)
8
amounts of coal and blast-furnace slag are adjusted based on the calcium oxide
content. Additionally, the reason that a quaternary system phase diagram
including Si02-Ca0-Mg0-A1203 for the case where the aluminum oxide content
is 20 wt.% was used is that there is little change in aluminum oxide content
5 when from 5% to 10% of blast-furnace slag is mixed with the coal, and it results
in nearly the same phase diagram as the case where the content of aluminum
oxide is 20 wt.%.
Industrial Applicability
10 [0052]
The blast-furnace injecting coal and the method for producing the same
according to the present invention can, at low cost, suppress adhesion of the
blast-furnace-injecting-coal ash and blockages caused by the
blast-furnace-injecting-coal ash along the path of the blast-furnace injecting
15 coal to the interior of the blast-furnace body, and therefore can be utilized
extremely advantageously in the steelmaking industry.
Reference Signs List
[0053]
20 11 Coal
12 Blast-furnace slag
13, 23 Blast-furnace injecting coal
2 4 Binder
25 Water
25 P1 Melting temperature of coal ash
P2 Melting temperature of ash from mixture
1 - 1 S l l - 2 Analysissteps
S 12- 1, S 12-2 Fine pulverization steps
S 13 Mixing step
,30 S 14 Pulverization step
S25 Molding step
CLAIMS
1. Blast-furnace injecting coal which is injected through a tuyere into an
interior of a blast-furnace body of a blast furnace;
a composition and a melting point of coal ash being analyzed in advance
and a composition of iron and steel slag produced by an iron and steel production
step being analyzed in advance;
the iron and steel slag containing more calcium oxide than the coal ash
does; and
the coal and the iron and steel slag being mixed, on the basis of the
composition and melting point of the coal ash and the composition of the iron and
steel slag, and in a manner such that a content of calcium oxide contained in a
quaternary system phase diagram including silicon dioxide, magnesium oxide,
aluminum oxide and calcium oxide, which are principal components of the coal
ash and the iron and steel slag, causes the melting point of the ash to be 1400°C or
higher.
2. The blast-furnace injecting coal according to claim 1, wherein
the coal has been pulverized to an average particle size of not greater than
1 mm, and
the iron and steel slag has been pulverized to a particle size of 20 pm to
100 pm.
3. The blast-furnace injecting coal according to claim 1, wherein
the blast-furnace injecting coal is formed by adding a binder and watcr to
a mixture of the coal and the iron and steel slag and molding into briquettes.
4. The blast-furnace injecting coal according to claim 2, wherein
the blast-furnace injecting coal is formed by adding a binder and water to
a mixture of the coal and the iron and steel slag and molding into briquettes.
5. A method for producing blast-furnace injecting coal which produces
blast-furnace injecting coal to be injected through a tuyere into an interior of a
blast-furnace body of a blast furnace, the method comprising performing:
an analysis step of analyzing a composition and a melting point of coal ash
and analyzing a composition of an iron and steel slag produced by an iron and
steel production step; and
a mixing step, in which the iron and steel slag contains more calcium oxide
than the coal ash does, and the coal and the iron and steel slag are mixed on the
basis of the composition and melting point of the coal ash and the composition of
the iron and steel slag, and in a manner such that a content of calcium oxide
contained in a quaternary system phase diagram'including silicon dioxide,
magnesium oxide, aluminum oxide and calcium oxide, which are principal
components of the coal ash and the iron and steel slag, causes the melting point of
the ash to be 1400°C or higher.
6. The method for producing blast-furnace injecting coal according to claim
5, wherein
the coal has been pulverized to an average particle size of not greater than
1 mm, and
the iron and steel slag has been pulverized to a particle size of 20 pm to
100 pm.
7. The method for producing blast-furnace injecting coal according to claim
6, the method further comprising performing:
in the mixing step, further adding a binder and water, and mixing with the
coal and the iron and steel slag; and
a molding step in which the mixture obtained in the mixing step is molded
into briquettes.