Slag component analysis method, slag basicity analysis method, and molten iron refining method

Patent metadata

Field	Value
Publication number	US-2024241058-A1
Application number	US-202218560104-A
Country	US
Kind code	A1
Filing date	Mar 10, 2022
Priority date	May 17, 2021
Publication date	Jul 18, 2024
Grant date	—

Abstract

Provided is a slag component analysis method capable of quickly and accurately measuring slag components generated during refining of molten iron. The method comprises: irradiating a surface of slag to be analyzed with a pulse laser a plurality of times to turn part of the slag into plasma; dispersing excitation light obtained from the slag turned into plasma and acquiring an emission spectrum of an element contained in the slag per one pulse laser irradiation or per a plurality of pulse laser irradiations; and deriving a target component concentration or component amount ratio from the acquired emission spectrum, wherein the slag to be analyzed is slag generated in a converter-type refining furnace, and in the process of turning part of the slag into plasma, the pulse laser is applied from a side of the converter-type refining furnace tilted to remove the slag generated in the converter-type refining furnace.

First claim

1 . A slag component analysis method comprising:
irradiating a surface of slag to be analyzed with a pulse laser a plurality of times to turn part of the slag into plasma by; dispersing excitation light obtained from the slag turned into plasma and acquiring an emission spectrum of an element contained in the slag per one pulse laser irradiation or per a plurality of pulse laser irradiations; and deriving a target component concentration or component amount ratio from the acquired emission spectrum, wherein the slag to be analyzed is slag generated in a converter-type refining furnace, and in the turning part of the slag into plasma, the pulse laser is applied from a side of the converter-type refining furnace tilted to remove the slag generated in the converter-type refining furnace.

2 . The slag component analysis method according to claim 1 , wherein in the turning part of the slag into plasma, the pulse laser is applied from a position that is closer to a throat of the converter-type refining furnace than a rotation axis of the converter-type refining furnace when the converter-type refining furnace is tilted.

3 . The slag component analysis method according to claim 1 , wherein in the deriving the target component concentration or component amount ratio, of all emission spectra acquired in the acquiring an emission spectrum per one pulse laser irradiation or per a plurality of pulse laser irradiations, only an emission spectrum in which an emission intensity of at least one element out of Ca, Si, Mg, and Al is greater than or equal to three times a standard deviation σ of noise of the emission spectra is used to derive the target component concentration or component amount ratio.

4 . The slag component analysis method according to claim 1 , wherein in the deriving the target component concentration or component amount ratio, a component concentration or component amount ratio of the slag is estimated from the acquired emission spectrum based on a slag component concentration or component amount ratio estimation model in which an emission spectrum acquired beforehand from slag whose component concentration or component amount ratio is known is an explanatory variable and the corresponding component concentration or component amount ratio in the slag is an objective variable, and the explanatory variable includes at least one emission spectrum in a wavelength range of at least part of the acquired emission spectrum.

5 . The slag component analysis method according to claim 4 , wherein the slag component concentration or component amount ratio estimation model is created through single regression or multivariate regression.

6 . The slag component analysis method according to claim 5 , wherein an analysis method of the multivariate regression is partial least squares.

7 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 4 .

8 . A molten iron refining method comprising
determining an amount of a slag-forming agent to be added for refining in a next process continuously performed in the converter-type refining furnace after deslagging, based on the basicity [CaO %/SiO 2 %] of the slag obtained using the slag basicity analysis method according to claim 7 .

9 . The molten iron refining method according to claim 8 , wherein the slag-forming agent contains one or more components selected from CaO, MgO, and FeO.

10 . The slag component analysis method according to claim 2 , wherein in the deriving the target component concentration or component amount ratio, of all emission spectra acquired in the acquiring an emission spectrum per one pulse laser irradiation or per a plurality of pulse laser irradiations, only an emission spectrum in which an emission intensity of at least one element out of Ca, Si, Mg, and Al is greater than or equal to three times a standard deviation σ of noise of the emission spectra is used to derive the target component concentration or component amount ratio.

11 . The slag component analysis method according to claim 2 , wherein in the deriving the target component concentration or component amount ratio, a component concentration or component amount ratio of the slag is estimated from the acquired emission spectrum based on a slag component concentration or component amount ratio estimation model in which an emission spectrum acquired beforehand from slag whose component concentration or component amount ratio is known is an explanatory variable and the corresponding component concentration or component amount ratio in the slag is an objective variable, and the explanatory variable includes at least one emission spectrum in a wavelength range of at least part of the acquired emission spectrum.

12 . The slag component analysis method according to claim 3 , wherein in the deriving the target component concentration or component amount ratio, a component concentration or component amount ratio of the slag is estimated from the acquired emission spectrum based on a slag component concentration or component amount ratio estimation model in which an emission spectrum acquired beforehand from slag whose component concentration or component amount ratio is known is an explanatory variable and the corresponding component concentration or component amount ratio in the slag is an objective variable, and the explanatory variable includes at least one emission spectrum in a wavelength range of at least part of the acquired emission spectrum.

13 . The slag component analysis method according to claim 10 , wherein the deriving the target component concentration or component amount ratio, a component concentration or component amount ratio of the slag is estimated from the acquired emission spectrum based on a slag component concentration or component amount ratio estimation model in which an emission spectrum acquired beforehand from slag whose component concentration or component amount ratio is known is an explanatory variable and the corresponding component concentration or component amount ratio in the slag is an objective variable, and the explanatory variable includes at least one emission spectrum in a wavelength range of at least part of the acquired emission spectrum.

14 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 5 .

15 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 6 .

16 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 11 .

17 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 12 .

18 . A slag basicity analysis method comprising
obtaining basicity [CaO %/SiO 2 %] of the slag using the slag component analysis method according to claim 13 .

Assignees

• Jfe Steel Corp

Inventors

• Inose Masao
• Sugawara Seiya

Classifications

• G01N2201/129

  Using chemometrical methods · CPC title

• G01N2201/0697

  Pulsed lasers · CPC title

• C21C5/4673

  Measuring and sampling devices · CPC title

• Y02P10/20

  Recycling · CPC title

• C21C5/28

  Manufacture of steel in the converter {(C21C5/005 takes precedence)} · CPC title