Method of producing molten iron

Patent metadata

Field	Value
Publication number	US-2025003684-A1
Application number	US-202218709516-A
Country	US
Kind code	A1
Filing date	Oct 26, 2022
Priority date	Dec 13, 2021
Publication date	Jan 2, 2025
Grant date	—

Abstract

Molten iron is obtained with a low electric power consumption rate by efficiently and reliably preheating a cold iron source by ascertaining the preheating state of the cold iron source. A method of producing molten iron in an electric furnace having a preheating chamber and a melting chamber includes: a cold iron source feeding step; a cold iron source preheating step having a preheating confirmation step; a supply step; and a melting step.

First claim

1 . A method of producing molten iron in an electric furnace having a preheating chamber and a melting chamber, the method comprising:
a cold iron source feeding step of feeding a cold iron source into the preheating chamber; a cold iron source preheating step of preheating the cold iron source fed in the cold iron source feeding step to a predetermined temperature by an exhaust gas generated in the melting chamber to be a preheated iron source, wherein the cold iron source preheating step includes a preheating confirmation step to confirm that the cold iron source is a preheated iron source that has been preheated to the predetermined temperature; a supply step of supplying the preheated iron source that has been confirmed to be preheated to the predetermined temperature in the preheating confirmation step to the melting chamber; and a melting step of melting the preheated iron source supplied to the melting chamber in the supply step by arc heating.

2 . The method of producing molten iron according to claim 1 , wherein the confirmation in the preheating confirmation step that the cold iron source is a preheated iron source that has been preheated to the predetermined temperature is performed based on an amount of change in amount of sensible heat of the exhaust gas.

3 . The method of producing molten iron according to claim 2 , wherein the amount of change in amount of sensible heat is calculated based on continuously measured temperature and flow rate of the exhaust gas and a weight of the cold iron source fed into the preheating chamber.

4 . The method of producing molten iron according to claim 2 , wherein the cold iron source is determined to be a preheated iron source that has been preheated to the predetermined temperature when the amount of change in amount of sensible heat calculated according to the following formula (1) is 700 kJ/(sec·t) or more:

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wherein
ΔQ is an amount of change in amount of sensible heat of the exhaust gas [KJ/(sec·t)];
Q 1 is an amount of sensible heat of the exhaust gas at the timing when the cold iron source is fed into the preheating chamber [kJ/(sec·t)];
Q N is an amount of sensible heat of the exhaust gas at any timing N after the timing when the cold iron source is fed into the preheating chamber, which is continuously calculated [kJ/(sec·t)];
c is a specific heat of the exhaust gas [kJ/(m 3 ·° C.)];
F 1 is a flow rate of the exhaust gas at the timing when the cold iron source is fed into the preheating chamber [m 3 /sec];
F N is a flow rate of the exhaust gas at any timing N after the timing when the cold iron source is fed into the preheating chamber, which is continuously measured [m 3 /sec];
T 1 is a temperature of the exhaust gas at the timing when the cold iron source is fed into the preheating chamber [° C.];
T N is a temperature of the exhaust gas at any timing N after the timing when the cold iron source is fed into the preheating chamber, which is continuously measured [° C.];
W 1 is a weight of the cold iron source in the preheating chamber at the timing when the cold iron source is fed into the preheating chamber [t]; and
W N is a weight of the cold iron source in the preheating chamber at any timing N after the timing when the cold iron source is fed into the preheating chamber [t].

5 . The method of producing molten iron according to claim 1 , wherein the supply of the preheated iron source to the melting chamber in the supply step is performed by an extruder.

6 . The method of producing molten iron according to claim 1 , wherein the supply of the preheated iron source to the melting chamber in the supply step is performed by free fall from a belt conveyor.

7 . The method of producing molten iron according to claim 3 , wherein the cold iron source is determined to be a preheated iron source that has been preheated to the predetermined temperature when the amount of change in amount of sensible heat calculated according to the following formula (1) is 700 KJ/(sec·t) or more:

Δ

Assignees

• Jfe Steel Corp

Inventors

• Tsutsumi Koichi
• Miwa Yoshihiro
• Takada Yosuke
• Todo Wataru
• Ozawa Sumito
• Kijima Hideo

Classifications

• F27D2019/0031

  through control of the flow of the exhaust gases · CPC title

• F27D2019/0021

  Monitoring the temperature of the exhaust gases · CPC title

• F27D2019/0006

  Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value · CPC title

• F27D17/18

  for preheating solid materials · CPC title

• F27B3/20

  Arrangements of heating devices · CPC title