Top-blowing lance for converter, method for adding auxiliary raw material, and method for refining of molten iron

Patent metadata

Field	Value
Publication number	US-2024076755-A1
Application number	US-202118272474-A
Country	US
Kind code	A1
Filing date	Dec 2, 2021
Priority date	Feb 1, 2021
Publication date	Mar 7, 2024
Grant date	—

Abstract

A method that, regarding a process of refining molten iron, can increase the thermal margin and the amount of cold iron source to be used. A burner having jetting holes for jetting a fuel and a combustion supporting gas is provided at a leading end part of one lance that top-blows an oxidizing gas to molten iron contained in a converter-type vessel, or at a leading end part of another separate lance. A powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is blown into the molten iron from the one lance or the other lance passes through a flame formed by the burner. This top-blowing lance for a converter is configured to secure a predetermined heating time and powder-fuel ratio. Also, a method for adding an auxiliary raw material and a method for refining of molten iron that use this top-blowing lance.

First claim

1 . A top-blowing lance for a converter, wherein:
a burner having jetting holes for jetting a fuel and a combustion supporting gas is provided at a leading end part of one lance that top-blows an oxidizing gas to molten iron contained in a converter-type vessel, or at a leading end part of another lance that is installed separately from the one lance; a powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is blown into the molten iron from the one lance or the other lance passes through a flame formed by the burner; and the top-blowing lance is configured to secure a predetermined heating time as well as a predetermined powder-fuel ratio.

2 . The top-blowing lance for a converter according to claim 1 , wherein
a distance l h (m) from a leading end of the lance having the burner to a molten metal surface and a discharge speed u p (m/s) of powder constituting the powdery auxiliary raw material or the auxiliary raw material processed into a powder form are determined so as to meet Expression 1 below, and a supply flow rate Q fuel (Nm 3 /min) of the fuel and a supply amount V p (kg/min) of the auxiliary raw material per unit time are determined so as to meet the relationship of Expression 2 below:

[

Expression
⁢

1

]



l
h

u
p

≥

t
0

(
1
)

[

Expression
⁢

2

]



V
p

Q
fuel

·

H
combustion

≥

C
0

(
2
)

where t 0 represents a required heating time (s) obtained from a particle diameter of the powdery auxiliary raw material or the auxiliary raw material processed into a powder form,
H combustion represents an amount of heat (MJ/Nm 3 ) generated by fuel combustion, and
C 0 represents a constant (kg/MJ).

3 . The top-blowing lance for a converter according to claim 2 , wherein
the required heating time to of the powdery auxiliary raw material or the auxiliary raw material processed into a powder form is determined from a particle diameter d p of the powdery auxiliary raw material or the auxiliary raw material processed into a powder form, an adiabatic flame temperature of the fuel, a flow velocity of a combustion gas of the fuel, and the discharge speed u p of the powder.

4 . The top-blowing lance for a converter according to claim 2 , wherein
the constant C 0 in Expression 2 is determined by a type of fuel gas to be used.

5 . A method for adding an auxiliary raw material when performing a refining process on molten iron contained in a converter-type vessel by supplying an oxidizing gas to the molten iron,
wherein, using the top-blowing lance for a converter according to claim 1 , a powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is part of the auxiliary raw material is blown into the molten iron so as to pass through a flame formed by the burner, and the powdery auxiliary raw material or the auxiliary raw material processed into a powder form is heated for a predetermined heating time or longer and jetted at a predetermined powder-fuel ratio.

6 . A method for performing a refining process on molten iron contained in a converter-type vessel by adding an auxiliary raw material and supplying an oxidizing gas to the molten iron,
wherein, using the top-blowing lance for a converter according to claim 1 , a powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is part of the auxiliary raw material is blown into the molten iron so as to pass through a flame formed by the burner, and the powdery auxiliary raw material or the auxiliary raw material processed into a powder form is heated for a predetermined heating time or longer and jetted at a predetermined powder-fuel ratio.

7 . The top-blowing lance for a converter according to claim 3 , wherein
the constant C0 in Expression 2 is determined by a type of fuel gas to be used.

8 . A method for adding an auxiliary raw material when performing a refining process on molten iron contained in a converter-type vessel by supplying an oxidizing gas to the molten iron,
wherein, using the top-blowing lance for a converter according to claim 2 , a powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is part of the auxiliary raw material is blown into the molten iron so as to pass through a flame formed by the burner, and the powdery auxiliary raw material or the auxiliary raw material processed into a powder form is heated for a predetermined heating time or longer and jetted at a predetermined powder-fuel ratio.

9 . A method for adding an auxiliary raw material when performing a refining process on molten iron contained in a converter-type vessel by supplying an oxidizing gas to the molten iron,
wherein, using the top-blowing lance for a converter according to claim 3 , a powdery auxiliary raw material or an auxiliary raw material processed into a powder form that is part of the auxiliary raw material is blown into the molten iron so as to pass through a flame formed by the burner, and the powdery auxiliary raw material or the auxiliary raw material processed into a powder form is heated for a predetermined heating time or longer and jetted at a predetermined powder-fuel ratio.

10 . A method for adding an auxiliary raw material when performing a refining process on molten iron contained in a converter-type vessel by supplying an oxidizing gas to the molten iron,
wherein, using the top-blowing lance for a converter according to claim 4 , a powdery auxiliary ra

Assignees

• Jfe Steel Corp

Inventors

• Amano Shota
• Negishi Hidemitsu
• Murakami Yumi
• Ogasawara Futoshi
• Nakase Kenji

Classifications

• F27D3/18

  Charging particulate material using a fluid carrier · CPC title

• C21C7/072

  Treatment with gases (C21C7/06, C21C7/064, C21C7/068 take precedence) · CPC title

• C21C7/0037 Primary

  by injecting powdered material · CPC title

• C21C5/35

  Blowing from above and through the bath · CPC title

• C21C5/4606

  Lances or injectors · CPC title