The kinetics of the nitrogen reaction with liquid iron-Sulfur alloys

Glaws, Peter; Fruehan, R. J.

doi:10.1007/bf02654853

Cited by 44 publications

(33 citation statements)

References 19 publications

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“…The adsorption coefficient for S, K S = 40, was taken from Reference 20, and f S /f°S was set to 3.5 in order to consider the effect of C on the activity coefficient of S. [21] Inserting Eq. [11] into Eq.…”

Section: Evaporation Of S From Liquid Fe-c-s Alloy: Role Of C and mentioning

confidence: 99%

Evaporation Mechanism of Sn and SnS from Liquid Fe: Part III. Effect of C on Sn Removal

Jung

Kang

Seo

et al. 2014

Metall Mater Trans B

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To understand the effect of C on Sn evaporation from liquid iron in the view of ferrous scrap recycling, the evaporation of Sn from various liquid Fe-C-S-Sn alloys was experimentally investigated. A series of gas-liquid reactions was carried out at 1873 K (1600°C) using an electromagnetic levitation melting technique, where mass transfers in gas phase and liquid phase did not significantly affect the reaction rate. It was found that CS 2 (g) is a major gas species evaporating from Fe-C-S alloy (initial S content [pct S] 0 : 0.028 to 0.502 mass pct), and Fe-C-SSn alloy ([pct S] 0 : 0.063 to 0.560 mass pct), thereby competing with SnS for S in the liquid alloy. A model equation for the evaporation rate of CS 2 (g) was established using the experimental data for the Fe-C-S alloys. The chemical reaction rate constant for the CS 2 (g) evaporation (k R CS2 ) was obtained as 4.24 9 10 -12 m 7 mol -2 s -1 , and the residual rate constant (k r CS2 ) was 4.24 9 10 -16 m 7 mol -2 s -1 , both at 1873 K (1600°C). Roll of C on the evaporation of Sn in Fe-C-Sn alloy was confirmed to be the increase of activity coefficient of Sn. By taking into account (1) the evaporation of Sn(g), SnS(g), and CS 2 (g), and (2) the increasing activity coefficient of Sn and S by C, a comprehensive model for the evaporation rate of Sn and S in the Fe-C-Sn-S alloy was developed. The calculation results by the developed model in the present study showed good agreement with the experimental results. Some applications of the current model are presented in the view of increasing the Sn removal rate.

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Section: Evaporation Of S From Liquid Fe-c-s Alloy: Role Of C and mentioning

confidence: 99%

Evaporation Mechanism of Sn and SnS from Liquid Fe: Part III. Effect of C on Sn Removal

Jung

Kang

Seo

et al. 2014

Metall Mater Trans B

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“…[1][2][3][4][5][6][7][8][9] Therefore, in order to know the maximum rate of nitrogen removal in steelmaking processes, it is important to understand the reaction mechanism of the interfacial chemical reaction of nitrogen gas with molten iron and the effect of surface active elements on the reaction.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9] The site blockage model assumes that surface active elements occupy the reaction sites and reaction only occurs on the vacant sites. Then, the reaction rates are expected to be proportional to the fraction of the vacant sites.…”

Section: Introductionmentioning

confidence: 99%

Interfacial Kinetics of Nitrogen with Molten Iron Containing Sulfur.

Morita

2003

ISIJ International

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“…Accordingly, it is important to evaluate the nitrogen dissolution rate in molten iron and many kinetic studies have been carried out. [1][2][3][4][5][6][7][8][9][10][11] One of the rate-limiting steps of nitrogen dissolution in molten iron is considered to be the adsorption and/or the dissociation of nitrogen at the metal surface. Several kinetic studies of investigating the effects of the alloying elements have been carried out.…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Concentration of Alloying Elements on Nitrogen Dissolution Rate in Molten Iron Alloys.

2003

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The effects of alloying elements, such as Mn, Cu and Mo, on the rate of nitrogen dissolution in the molten iron alloys are investigated by an isotope exchange technique at 1 973 K. The rate constant of nitrogen dissolution increases with increasing the content of Mn or Mo, which has stronger affinity with nitrogen than iron. On the other hand, the rate constant decreases with increasing the Cu content, which has a repulsive force against nitrogen in iron. The mole fractions of the alloying elements in the surface phase are estimated, and the reaction mechanism is discussed by investigating the dependence of the rate constant on the mole fraction in the surface phase. The effect of alloying elements on the nitrogen dissolution rate depends on the affinity of the solute element with nitrogen in molten iron and the mole fraction in the surface phase.KEY WORDS: nitrogen dissolution; isotope exchange; surface concentration; Butler's equation. where N 0 is Avogadro's number, and V X is the molar volume of pure liquid X (m 3 /mol). L in Eq. (2) is usually set to be 1.091 for liquid metals, assuming close-packed structures. 17) N X S and N X B in Eq.(1) are mole fractions of a component X in a surface phase and a bulk phase, respectively; G -X E,S (T, N B S ) is the partial excess Gibbs energy of X in the surface phase as a function of T and N B S ; G -) is the partial excess Gibbs energy of X in the bulk phase as a function of T and N B B (XϭA or B). Equation (1) can be solved from the relationship between excess Gibbs energy in bulk and surface phases as follows. Since G -(T, N B B ) in Eq.(1) can be obtained directly from thermodynamic databases, we only need the additional information on G -X E,S (T, N B S ) in the surface phase. The various authors proposed the models for G -X E,S (T, N B S ), which can be summarized as follows: (1), the surface tension s of the liquid alloy can be also calculated. The mole fraction of each component element in a surface phase for binary iron alloy was estimated using thermodynamic data 13,18,19) at 1 973 K. The results are shown in Fig. 1. The mole fractions of manganese and copper are found to be higher in the surface phase. On the other hand, the mole fractions of tungsten and molybdenum are lower in the surface phase. In order to investigate the effect of surface concentration of alloying elements on nitrogen dissolution rate, manganese, copper and molybdenum were selected as the alloying elements. ExperimentalAn alumina crucible (26 mm O.D., 20 mm I.D.), in which high-purity electrolytic iron ([mass ppm S]ϭ7, [mass ppm P]ϭ3) and M [M: Mn (purity 99.95 %), Cu (purity 99.0 %) or Mo (purity 99.9 %)] totally weighing 60 g were contained, was settled in a transparent quartz furnace tube (65 mm O.D., 62 mm I.D.) and inductively heated up to 1 873 K in an Ar-H 2 mixture. The iron sample was held for 1 to 2 h in the Ar-H 2 mixture and was sufficiently deoxidized at 1 873 K. Then, the iron sample was cooled rapidly. Using the prepared samples, the measurements were carried out as f...

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The kinetics of the nitrogen reaction with liquid iron-Sulfur alloys

Cited by 44 publications

References 19 publications

Evaporation Mechanism of Sn and SnS from Liquid Fe: Part III. Effect of C on Sn Removal

Evaporation Mechanism of Sn and SnS from Liquid Fe: Part III. Effect of C on Sn Removal

Interfacial Kinetics of Nitrogen with Molten Iron Containing Sulfur.

Effect of Surface Concentration of Alloying Elements on Nitrogen Dissolution Rate in Molten Iron Alloys.

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