Behavior of desulfurization in ladle steel refining with powder injection at reduced pressures.

Tsujino, Ryoji; Nakashima, Junji; Hirai, Masazumi; Yamada, Yasutaka

doi:10.2355/isijinternational.29.92

Cited by 19 publications

(15 citation statements)

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“…At the slag/metal interface, the reverse of reaction (1) takes place (effectively transferring sulphur from the slag back to the metal). On the other hand, part of the sulphur (15-25%) is directly oxidised via reaction (14) and leaves the process 3,10 .…”

Section: Sulphur Removal In the Convertermentioning

confidence: 99%

Sulphur removal in ironmaking and oxygen steelmaking

Schrama

Beunder

Berg

et al. 2017

Ironmaking & Steelmaking

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Sulphur removal in the ironmaking and oxygen steelmaking process is reviewed. A sulphur balance is made for the steelmaking process of Tata Steel IJmuiden, the Netherlands. There are four stages where sulphur can be removed: in the blast furnace (BF), during hot metal (HM) pretreatment, in the converter and during the secondary metallurgy (SM) treatment. For sulphur removal a low oxygen activity and a basic slag are required. In the BF typically 90% of the sulphur is removed; still, the HM contains about 0.03% of sulphur. Different HM desulphurisation processes are used worldwide. With co-injection or the Kanbara reactor, sulphur concentrations below 0.001% are reached. Basic slag helps desulphurisation in the converter. However, sulphur increase is not uncommon in the converter due to high oxygen activity and sulphur input via scrap and additions. For low sulphur concentrations SM desulphurisation, with a decreased oxygen activity and a basic slag, is always required.

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Section: Sulphur Removal In the Convertermentioning

confidence: 99%

Sulphur removal in ironmaking and oxygen steelmaking

Schrama

Beunder

Berg

et al. 2017

Ironmaking & Steelmaking

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“…Some researchers recommended [61][62][63] that the oxygen activity of molten steel at the slag-metal interface a O,interface , rather than that of molten steel bulk a O,bath , is more reasonable to represent the oxygen activity of molten steel at the slag-metal interface and to affect the desulfurization reactions seriously. Considering that the LF refining process proceeds with higher binary basicity of slags as well as lower a O,bath of molten steel, it is more logical that the a O,interface of molten steel at the slagmetal interface, i.e., at desulfurization zone, is determined based on the equilibrium of species in molten steel and their corresponding oxides in slags.…”

Section: Comparison Of Oxygen Activity Of Molten Steel At Slag-metal mentioning

confidence: 99%

A Thermodynamic Model of Sulfur Distribution Ratio between CaO–SiO2–MgO–FeO–MnO–Al2O3 Slags and Molten Steel during LF Refining Process Based on the Ion and Molecule Coexistence Theory

Yang

Shi

Zhang

et al. 2011

Metall Mater Trans B

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A thermodynamic model for calculating the sulfur distribution ratio between ladle furnace (LF) refining slags and molten steel has been developed by coupling with a developed thermodynamic model for calculating the mass action concentrations of structural units in LF refining slags, i.e., CaO-SiO 2 -MgO-FeO-MnO-Al 2 O 3 hexabasic slags, based on the ion and molecule coexistence theory (IMCT). The calculated mass action concentrations of structural units in CaO-SiO 2 -MgO-FeO-Al 2 O 3 -MnO slags equilibrated or reacted with molten steel show that the calculated equilibrium mole numbers or mass action concentrations of structural units or ion couples, rather than mass percentage of components, in the slags can represent their reaction abilities. The calculated total sulfur distribution ratio shows a reliable agreement with the measured or the calculated sulfur distribution ratio between the slags and molten steel by other models under the condition of choosing oxygen activity based on (FeO)-[O] equilibrium. Meanwhile, the developed thermodynamic model for calculating sulfur distribution ratio can quantitatively determine the respective contribution of free CaO, MgO, FeO, and MnO in the LF refining slags. A significant difference of desulfurization ability among free component as CaO, MgO, FeO, and MnO has been found with approximately 87-93 pct, 11.43-5.85 pct, 0.81-0.60 pct and 0.30-0.27 pct at both middle and final stages during LF refining process, respectively. A large difference of oxygen activity is found in molten steel at the slag-metal interface and in bulk molten steel. The oxygen activity in molten steel at the slag-metal interface is controlled by (FeO)-[O] equilibrium, whereas the oxygen activity in bulk molten steel is controlled by [Al]- [O] equilibrium. Decreasing the high-oxygen-activity boundary layer beneath the slag-metal interface can promote the desulfurization reaction rate effectively or shorten the refining period during the LF refining process.

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“…Tsujino et al pointed out that oxygen activity at slag–steel interface was related to both the (FeO + MnO) content of slag and the dissolved oxygen activity of steel. In the present experiments, the dissolved oxygen activity of steel estimated by Al–O equilibrium thermodynamics was almost the same for all the heats, thus the oxygen activity at slag–steel interface was mainly related to the (FeO + MnO) content of slag, which indicated that (FeO + MnO) content in slag can be also decreased by increasing silicon content in steel.…”

Section: Resultsmentioning

confidence: 99%

Influence of Silicon on Desulfurization of Al-Killed Steel by CaO-Al₂O₃Slag Contained FeO and MnO

Huang

Wang

et al. 2016

steel research int.

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Industry trials of slag-washing desulfurization in LD tapping process are performed to study the influence of silicon on desulfurization of Al-killed steel using CaO-Al 2 O 3 slag contained FeO and MnO. Influence of silicon on desulfurization is found to be great, while the influences of aluminum and manganese on desulfurization are negligible. Oxygen activity at slag-steel interface together with the (FeO þ MnO) content in slag, decreased with the rise of silicon content, which is considered as the main reason of different desulfurization efficiencies between Si-free steel and Si-containing steel. Oxygen activity at slag-steel interface is reduced more sharply by increasing the silicon content than that by increasing the aluminum content. As a result, desulfurization efficiency can be enhanced significantly with the rise of silicon content, rather than the aluminum content. Furthermore, the influence of silicon on desulfurization can be magnified if the slag contained FeO and MnO, while negligible for the slag with few FeO and MnO.

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Behavior of desulfurization in ladle steel refining with powder injection at reduced pressures.

Abstract: +r/(1-Tg/Tl)} """"""""""""""""'(1) of (Fe0+MnO) in the slag, which exerts a large effect on desulfurization as described later.

Cited by 19 publications

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Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in ironmaking and oxygen steelmaking

A Thermodynamic Model of Sulfur Distribution Ratio between CaO–SiO2–MgO–FeO–MnO–Al2O3 Slags and Molten Steel during LF Refining Process Based on the Ion and Molecule Coexistence Theory

Influence of Silicon on Desulfurization of Al-Killed Steel by CaO-Al₂O₃Slag Contained FeO and MnO

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Behavior of desulfurization in ladle steel refining with powder injection at reduced pressures.

Abstract: +r/(1-Tg/Tl)} """"""""""""""""'(1) of (Fe0+MnO) in the slag, which exerts a large effect on desulfurization as described later.

Cited by 19 publications

References 0 publications

Sulphur removal in ironmaking and oxygen steelmaking

Sulphur removal in ironmaking and oxygen steelmaking

A Thermodynamic Model of Sulfur Distribution Ratio between CaO–SiO2–MgO–FeO–MnO–Al2O3 Slags and Molten Steel during LF Refining Process Based on the Ion and Molecule Coexistence Theory

Influence of Silicon on Desulfurization of Al-Killed Steel by CaO-Al2O3Slag Contained FeO and MnO

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Influence of Silicon on Desulfurization of Al-Killed Steel by CaO-Al₂O₃Slag Contained FeO and MnO