US2025283185A1PendingUtilityA1
Method for melting direct reduced iron, solid iron and method for producing the same, material for civil engineering and construction and method for producing the same, and system for melting direct reduced iron
Est. expiryApr 22, 2042(~15.7 yrs left)· nominal 20-yr term from priority
C22B 7/04C21B 2200/00C21B 13/02C21B 13/143C21B 13/12C21B 13/004C21B 13/008C21B 13/0006C21B 2400/022
61
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Claims
Abstract
A technology for melting direct reduced iron while efficiently removing a gangue portion from the direct reduced iron, including obtaining a direct reduced iron by bringing iron ore or a mixture thereof and composition adjusting material together with a reducing material under heating; melting the direct reduced iron to obtain molten iron, and removing a slag outside the induction melting furnace; and optionally refining the molten iron. A charging temperature of melting the direct reduced iron ranges from after finishing direct reduction to atmospheric temperature; and melting includes blowing gas into the molten iron for a limited time of or throughout melting, and optionally includes one or more steps: 1) adding an adjuster for adjusting components of the slag, 2) supplying heat to the slag from a heat source disposed above the induction melting furnace, and 3) supplying one or more reducing solids and/or one or more reducing gases.
Claims
exact text as granted — not AI-modified1 . A method for melting direct reduced iron, comprising:
a direct reduction step of obtaining a direct reduced iron by bringing iron ore or a mixture of iron ore and a composition adjusting material into contact with a reducing material under heating; a melting step of melting the direct reduced iron in an induction melting furnace to produce molten iron; a slag removal step of removing slag produced in the melting step to an outside of the induction melting furnace; and, optionally, a refining step of refining the molten iron obtained in the melting step, wherein
a charging temperature of the direct reduced iron into the induction melting furnace in the melting step of melting the direct reduced iron is in a range from a temperature after finishing the direct reduction step to atmospheric temperature, and
the melting step includes a first step of blowing gas into the molten iron for a limited time of or throughout the melting step, and, optionally, one or more steps selected from
1) a second step of adding a slag composition adjusting material,
2) a third step of supplying heat to the slag from a heat source disposed above the induction melting furnace, and
3) a fourth step of supplying one or more reducing solids and/or one or more reducing gases.
2 . The method for melting direct reduced iron according to claim 1 , wherein
the first step includes, provided that a height H(m) from a position of a gas supply nozzle for blowing the gas into the molten iron to a bath surface of the molten iron is represented by following Formula (1), blowing the gas into the molten iron so as to satisfy following Formula (2):
H
=
1
.
2
7
×
W
DRI
/
(
ρ
1
D
2
)
×
(
%
T
·
Fe
)
DRI
/
100
-
h
(
1
)
H
>
0.18
×
(
ρ
g
Q
2
/
ρ
1
N
2
d
2
)
1
/
3
,
(
2
)
where ρ g represents a density (kg/m 3 ) of the supplied gas,
ρ l represents a density (kg/m 3 ) of the molten iron,
Q represents a supply rate (Nm 3 /minute) of the gas,
N represents the number (−) of gas supply nozzles,
d represents a diameter (m) of each gas supply nozzle,
D represents an inner diameter (m) of the induction furnace,
W DRI represents a weight (kg) of reduced iron supplied into the induction furnace,
(% T.Fe) DRI represents a total iron concentration (mass %) in the reduced iron, and
h represents a height (m) from a bottom of the induction furnace to the position of the gas supply nozzle.
3 . The method for melting direct reduced iron according to claim 1 , wherein
the second step comprises adjusting a type and amount of the slag composition adjusting material added so that the composition of the slag produced in the melting step can achieve a basicity, which is a ratio of a CaO concentration (% CaO) to a SiO 2 concentration (% SiO 2 ) on a mass basis, in a range of 0.5 to 2.0 and an Al 2 O 3 concentration (% Al 2 O 3 ) in a range of 10 to 25 mass %.
4 . The method for melting direct reduced iron according to claim 1 , wherein
the fourth step comprises adjusting a type and amount of the reducing solid(s) and/or reducing gas(es) to be supplied so that the composition of the slag produced in the melting step can achieve a total iron concentration (% T.Fe) of 20 mass % or less.
5 . A method for producing solid iron, comprising solidifying the molten iron obtained with the method according to claim 1 to obtain solid iron.
6 . Solid iron produced by the method according to claim 5 , wherein:
a total iron concentration T.Fe is 93 mass % or more, and a total content of oxide components other than Fe is 3 mass % or less.
7 . A method for producing a material for civil engineering and construction, comprising:
a melting step of melting direct reduced iron in an induction melting furnace to obtain molten iron, a slag removal step of removing slag produced in the melting step to an outside of the melting furnace, and a cooling solidification step of cooling the slag removed in the slag removal step to solidify the slag into a raw material for civil engineering and construction, wherein
a charging temperature of the direct reduced iron into the induction melting furnace in the melting step of melting the direct reduced iron is in a range from a temperature after finishing the direct reduction step to atmospheric temperature, and
the melting step includes a first step of blowing gas into the molten iron for a limited time of or throughout the melting step, and, optionally, one or more steps selected from
1) a second step of adding a slag composition adjusting material and
2) a third step of supplying heat to the slag from a heat source disposed above the induction melting furnace.
8 . A material for civil engineering and construction produced with the method according to claim 7 , wherein:
a basicity that is a ratio in mass of a CaO concentration (% CaO) to a SiO 2 concentration (% SiO 2 ) is in a range of 0.5 to 2.0, and an Al 2 O 3 concentration (% Al 2 O 3 ) is in a range of 10 to 25 mass %.
9 . A system for melting direct reduced iron, comprising:
a direct reduction furnace that is configured to obtain a direct reduced iron by bringing iron ore or a mixture of iron ore and a composition adjusting material into contact with a reducing material under heating; an induction melting furnace that is configured to obtain a molten iron by melting the direct reduced iron; and a slag removal mechanism that is configured to discharge a slag generated in the induction melting furnace to an outside of the melting furnace; and further optionally comprising:
a refining facility that is configured to refine the molten iron melted in the induction melting furnace,
wherein:
the direct reduced iron that is to be melted in the induction melting furnace is charged into the induction melting furnace at a temperature of a range from a temperature after finishing the direct reduction treatment to atmospheric temperature, the induction melting furnace includes a function of blowing a gas into the molten iron for a limited time of or throughout the melting of the direct reduced iron, and further optionally includes one or more functions selected from:
1) a function of adding an adjuster for adjusting components of the slag,
2) a function of supplying heat to the slag from a heat source disposed above the induction melting furnace, and
3) a function of supplying one or more reducing solids or gases.
10 . The system for melting direct reduced iron according to claim 9 , wherein the system comprises two or more said induction melting furnaces with respect to one said direct reduction furnace.
11 . A method for producing solid iron, comprising solidifying the molten iron obtained with the method according to claim 2 to obtain solid iron.
12 . A method for producing solid iron, comprising solidifying the molten iron obtained with the method according to claim 3 to obtain solid iron.
13 . A method for producing solid iron, comprising solidifying the molten iron obtained with the method according to claim 4 to obtain solid iron.
14 . Solid iron produced by the method according to claim 11 , wherein:
a total iron concentration T.Fe is 93 mass % or more, and a total content of oxide components other than Fe is 3 mass % or less.
15 . Solid iron produced by the method according to claim 12 , wherein:
a total iron concentration T.Fe is 93 mass % or more, and a total content of oxide components other than Fe is 3 mass % or less.
16 . Solid iron produced by the method according to claim 13 , wherein:
a total iron concentration T.Fe is 93 mass % or more, and a total content of oxide components other than Fe is 3 mass % or less.Join the waitlist — get patent alerts
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