Development and Prospects of Refining Techniques in Steelmaking Process

Kikuchi, Naoki

doi:10.2355/isijinternational.isijint-2020-186

Cited by 28 publications

(17 citation statements)

References 70 publications

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“…7) This has been conventionally realized and implemented using an argon oxygen decarburization (AOD) furnace with the dilution of CO gas by argon gas and a vacuum oxygen decarburization (VOD) furnace with a reduction in the partial pressure of CO by evacuation during the production of stainless steel. [8][9][10][11][12] However, the perfect suppression of Cr loss is not feasible in principle when applying these elaborate decarburization processes because of the intrinsically negative large Gibbs energy for the formation of chromium oxide at steel production temperatures. Hence, the addition of silicon as a reducing agent is necessary to recover Cr from slag to obtain molten crude stainless steel 13) from the viewpoint of maximizing the yield of Cr in the alloy and possibly lowering the Cr concentration in slag, considering the potential environmental pollution and subsequent harmful effects on human health.…”

Section: Introductionmentioning

confidence: 99%

Determination of Solubility of Chromium Oxide in the CaO–SiO2–Cr2O3 Slag System at 1873 K under Moderately Reducing Conditions

2021

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For a better thermodynamic understanding of the optimization of molten slag in the stainless-steel refining process, the solubility of chromium oxide in the CaO-SiO 2 -Cr 2 O 3 slag system was investigated. A chemical equilibrium technique was employed in which molten slag and solid Cr 2 O 3 pellets were equilibrated under a regulated oxygen partial pressure ( ) O2 P lower than 10 − 11 atm at 1 873 K. The mass ratio of CaO to SiO 2 ( / )CaO S iO2 X X, as an index of slag basicity, was varied from 0.5 to 1.5. A CO-CO 2 -Ar gas mixture was used, and the oxygen partial pressure was precisely controlled by evaluating possible contamination by oxygen that was inevitably introduced into the gas mixture system. A zirconia oxygen sensor was used to directly measure the oxygen partial pressure for this evaluation. The solubility of chromium oxide increased with decreasing slag basicity and oxygen partial pressure. Accordingly, slag design is a huge prospect toward achieving desirable refining conditions.

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Section: Introductionmentioning

confidence: 99%

Determination of Solubility of Chromium Oxide in the CaO–SiO2–Cr2O3 Slag System at 1873 K under Moderately Reducing Conditions

2021

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“…There are many fundamental studies that consider metallurgical processes. Thus, paper [4] analyzed the development of refining technologies in the steel production process over the past 60 years and their prospects for the future, with the aim of reducing the cost of processing and improving the quality of steel.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Devising criteria for the authenticity of historical cold weapons based on X-ray fluorescence analysis of their surface

Merezhko

Vovk

Indutnyi

et al. 2021

EEJET

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This paper reports the results of studying the chemical composition of the surface of 4 objects of cold weapons of the 19th and early 20th centuries, made of iron – bayonet knives and sabers. This makes it possible to establish the signs of authenticity of cold weapon samples made of iron in that chronological period. An authentic procedure has been proposed for examining the chemical composition of the surface of historical objects of cold weapons by rubbing the samples with cotton wool swabs and their subsequent investigation. This makes it possible to explore objects of cold weapons, whose size is large, as well as simplify the very procedure for studying objects of historical and cultural value. Using the X-ray fluorescent chemical analyzer Expert Mobile, chemical elements were found at the surface of samples of cold weapons made of iron. The presence of such elements is the result of the process of re-crystallization and self-purification of metal during a long history of its life. Elements found in almost every rubbing sample were identified: calcium, ferrum, zinc, cuprum, and chlorine. The studies of cold weapons samples testify to the heterogeneity of the composition of patina formations on their surface, which confirms the authenticity of ancient objects. In addition, the studies have shown a difference in the chemical composition of surface layers of different parts of individual samples of antique cold weapons, which may indicate different times or different technology for their manufacture. The fluorescence spectra of the obtained rubbing of individual samples of cold weapons were compared with "pure" material, which made it possible to identify elements removed from the surface of objects. The study results are important indicators to confirm the authenticity of cultural monuments and the technology of their manufacture in the past.

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“…[26] To quantitatively express the thermodynamic properties of liquid slag, the sulfide capacity (C S 2À ) of the liquid slag (not the bulk slag) was calculated using FactSage TM 7.3 software and is shown in Figure 10, which includes for comparison data on FMS and RM fluxing from the present authors' previous study. [26] Even though the porous solid CaO can absorb sulfur from molten steel via the so-called 'Capillary refining' mechanism, [33][34][35][36] it is generally known that the solid CaO did not participate in the desulfurization reaction in view of slag chemistry theory. [37] Hence, in present study, it was assumed that solid CaO [approx.…”

Section: B Effect Of White Mud On Desulfurization Kinetics Of Molten Steelmentioning

confidence: 99%

Effect of White Mud Addition on Desulfurization Rate of Molten Steel

Jeong

Chung

et al. 2021

Metall Mater Trans B

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Fluorspar (CaF2) is commonly used to control the fluidity of slag in ladle-refining of steel. However, because it is desirable to reduce CaF2 consumption because of its environmental impacts, the industrial waste material such as white mud (WM) was investigated as a potential substitute for fluorspar. Steel sample (Fe-0.3C-0.9Mn-0.3Si-0.03Al-0.05S, mass pct) was melted in a high-frequency induction furnace, followed by additions of ladle slag (CaO-Al2O3-SiO2-5MgO-xCaF2, CaO/Al2O3=3, x = 0 to 10 mass pct) and fluxing agent (WM) at 1823 K (1550 °C). The desulfurization experiments were carried out by reducing CaF2 content in the ladle slag and increasing the addition of WM. Ladle slag with added WM showed an overall mass transfer coefficient of sulfur (kO) equivalent to or higher than that of conventional 10 mass pct CaF2-containing ladle slag. In a slag melting experiment based on DIN 51730 standard, the melting rate of mixed slag increased with the amount of WM added, which is considered to have a positive effect on the initial desulfurization rate. In addition, adding WM provided sulfide capacity of the slag equivalent to that of CaF2-containing slag. Consequently, the use of WM yielded slag having $$k_{{\text{O}}}$$ k O equivalent to or higher than that of conventional ladle slag with 10 pct CaF2, and thus, WM shows promise as a partial replacement for fluorspar.

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Development and Prospects of Refining Techniques in Steelmaking Process

Cited by 28 publications

References 70 publications

Determination of Solubility of Chromium Oxide in the CaO–SiO<sub>2</sub>–Cr<sub>2</sub>O<sub>3</sub> Slag System at 1873 K under Moderately Reducing Conditions

Determination of Solubility of Chromium Oxide in the CaO–SiO<sub>2</sub>–Cr<sub>2</sub>O<sub>3</sub> Slag System at 1873 K under Moderately Reducing Conditions

Devising criteria for the authenticity of historical cold weapons based on X-ray fluorescence analysis of their surface

Effect of White Mud Addition on Desulfurization Rate of Molten Steel

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