Thermodynamic study of MnO-SiO2-Al2O3 slag system: Liquidus lines and activities of MnO at 1823 K

Woo, Dae-Hee; Kang, Youn‐Bae; Lee, Hae-Geon

doi:10.1007/s11663-002-0075-5

Cited by 24 publications

(19 citation statements)

References 7 publications

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“…From the experimental data shown in the Figure 1, it is also shown that, for the c MnO(s) in Al 2 O 3 -containing systems, the effect of Al 2 O 3 on the c MnO(s) is not remarkable in the range of concentration investigated in the present study as well as in the work of Woo et al [13] The c MnO(s) is plotted as a function of concentration of AlO 1.5 in Figure 2 Figures 1 and 2, it is not so certain whether the presence of MnS affects the c MnO(s) or not. From the experimental data obtained in the present study, c MnO(s) in the liquid oxysulfide seems a bit higher than that in liquid oxide without sulfur, within experimental scatters.…”

Section: A Activity Of Mn (A Mn ) In Pt-mn Alloysupporting

confidence: 68%

“…In a previous investigation, [13] however, the latter chemical removal did not produce a big difference in the Mn concentration of Pt-Mn alloy. After the pretreatment, Mn concentrations were measured by the inductively coupled plasma (ICP) method after the alloy was completely dissolved in the acid (HCl 14 mL + HNO 3 6 mL), whereas heat was applied.…”

Section: Methodsmentioning

confidence: 57%

“…In the present study, component ''AlO 1.5 '' is used instead of Al 2 O 3 . Also shown are the c MnO(s) in MnO-SiO 2 at 1773 K (1500°C) by Rao and Gaskell, [27] and the MnO-SiO 2 -AlO 1.5 system at 1823 K (1550°C) by Woo et al [13] All of those exhibit the same tendency such that the c MnO(s) decreases as X SiO2 /(X MnO + X SiO2 ) increases. This is because MnO and SiO 2 in molten oxysulfide (or molten oxide) exhibit a strong short-range ordering (chemical attraction).…”

Section: A Activity Of Mn (A Mn ) In Pt-mn Alloymentioning

confidence: 86%

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Thermodynamics of MnO-SiO2-Al2O3-MnS Liquid Oxysulfide: Experimental and Thermodynamic Modeling

Kim

Woo

Gaye

et al. 2011

Metall Mater Trans B

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The activities of MnO and MnS in a MnO-SiO 2 -Al 2 O 3 (or AlO 1.5 )-MnS liquid oxysulfide solution were investigated by employing the gas/liquid/Pt-Mn alloy chemical equilibration technique under a controlled atmosphere at 1773 K (1500°C). Also, the sulfide capacity, defined as C S = (wt pct S)(pO 2 /pS 2 ) 1/2 , in MnO-SiO 2 -Al 2 O 3 slag with a dilute MnS concentration was obtained from the measured experimental data. As X SiO2 /(X MnO + X SiO2 ) in liquid oxysulfide increases, the activity coefficient of MnO decreases, while that of MnS first increases and then decreases. As X(AlO 1.5 ) in liquid oxysulfide increases, the activity coefficient of MnS increases, while no remarkable change is observed for the activity coefficient of MnO. The behavior of the activity coefficient of MnS was qualitatively analyzed by considering MnO + A x S y (SiS 2 or Al 2 S 3 ) = MnS + A x O y (SiO 2 or Al 2 O 3 ) reciprocal exchange reactions in the oxysulfide solution. The behavior was shown to be consistent with phase diagram data, namely, the MnS saturation boundary. Quantitative analysis of the activity coefficient of the oxysulfide solution was also carried out by employing the modified quasichemical model in the quadruplet approximation.

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Section: A Activity Of Mn (A Mn ) In Pt-mn Alloysupporting

confidence: 68%

Section: Methodsmentioning

confidence: 57%

Section: A Activity Of Mn (A Mn ) In Pt-mn Alloymentioning

confidence: 86%

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Thermodynamics of MnO-SiO2-Al2O3-MnS Liquid Oxysulfide: Experimental and Thermodynamic Modeling

Kim

Woo

Gaye

et al. 2011

Metall Mater Trans B

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“…CaO may also come from interaction of the molten steel reacts with CaO-based top slag in a ladle or tundish. Many experimental studies [1][2][3][4][5][6][7][8] have been performed on MnO-Al 2 O 3 -SiO 2 inclusion systems. In addition, several thermodynamic calculations, [9][10][11][12][13][14][15][16][17] simply based on the activity of slag and interaction parameters of alloying elements (such as Mn, Si, Al and O) in steel, have been conducted in order to help control MnO-Al 2 O 3 -SiO 2 type of inclusions.…”

Section: Introductionmentioning

confidence: 99%

Inclusions Chemistry for Mn/Si Deoxidized Steels: Thermodynamic Predictions and Experimental Confirmations

2004

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Inclusions chemistry of Mn/Si deoxidized steel was studied through both thermodynamic computation and experimental method. The computational thermodynamics has proved to provide a powerful tool for controlling inclusions and precipitates in steel. For Mn/Si deoxidized steels, important factors in determining the liquidus temperature and primary phase of the inclusions are MnO/SiO 2 ratio and Al 2 O 3 content in inclusions. Provided that no further interaction with steel matrix during cooling, inclusions having MnO/SiO 2 mass% ratio near unity and Al 2 O 3 content in the range of 10-20 mass% give low liquidus temperatures (1150-1200°C) and primary phases of MnSiO 3 and Mn 3 Al 2 Si 3 O 12 both which are soft. For the case of MnϩSiϭ1.0 in mass%, the Mn/Si ratio of 2-5 meets the above conditions. Effect of the top slag on the inclusions chemistry can be predicted with accuracy, and hence it is possible to control the inclusions chemistry through proper design of the top slag composition so that the inclusions show a low liquidus temperature and soft primary phase. As the inclusions composition gradually changes with time toward the top slag composition, the length of refining time which determines the extent of reaction with the top slag is an important factor in determining the inclusions chemistry.KEY WORDS: inclusion; Mn/Si deoxidation; metal-inclusion reaction; the CaO-MnO-SiO 2 -Al 2 O 3 system; computational thermodynamics. namic computations, a thermodynamic database for slag and inclusion, which was optimized by the present authors, [19][20][21] was used, and all calculations were performed using the FactSage thermochemical software. 22) Thermodynamic Basis-Models and Database Liquid SteelMost investigators have used interaction parameter formalism developed by Wagner 23) and extended by Sigworth and Elliot. 24) This formalism has been widely used in metallurgy to calculate activity/activity coefficients of solutes in liquid steel. Many experiments have been conducted to evaluate interaction parameters among metallic elements, O, C, S, N etc. in molten iron and are well documented in the literature. 24,25) However, it fails sometimes to reproduce experimental data, particularly for those cases of 1) a highly concentrated region or 2) containing strong deoxidizer such as Al, Ca and Mg. In order to solve these problems in a thermodynamically sound way, Pelton and Bale 26-28) developed Unified Interaction Parameter Formalism (UIPM) which modifies Wagner formalism 23,24) and Darken formalism. 29) Moreover, in order to reproduce the deoxidation phenomena when strong deoxidizing elements exist, Jung et al. 30) proposed the use of associates such as Al*O, Ca*O, Si*O etc. in molten iron with UIPM. This UIPM with associates shows excellent agreement between calculation and experiments for deoxidation phenomena in liquid steel with a few model parameters. 30) Therefore, UIPM with associates was used to describe thermodynamic properties for liquid steel. All interaction parameters required for deoxidation of Mn, ...

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“…This has recently been confirmed by MnO-activity measurements in the MnO-SiO 2 -Al 2 O 3 system. [41] The cell model, on the other hand, is unable to describe correctly phase equilibria in the area of mullite saturation. However, since the low MnO region is essential for simulations related to the silicomanganese smelting process, and since phase equilibria in the area of mullite saturation are relatively unimportant for both high carbon ferromanganese slags and silicomanganese slags, it has been decided to use the cell model [12,13,14] in this work.…”

Section: Introductionmentioning

confidence: 99%

Computer simulation of equilibrium relations in managanese ferroalloy production

Tang

Olsen

2006

Metall Mater Trans B

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The complex heterogeneous equilibria associated with the production of manganese ferroalloys have been simulated using recently developed thermochemical databases. Over 600 measured equilibrium data have been used to verify and calibrate the model calculations. Good agreement is obtained for many important technical relations such as carbon solubility, equilibrium diagrams and phase relations, and element distribution as a function of temperature and composition. Experimental slag/metal and slag/metal/gas equilibria in MnO-SiO 2 binary, MnO-SiO 2 -CaO and MnO-SiO 2 -Al 2 O 3 ternary, MnO-SiO 2 -CaO-Al 2 O 3 quaternary, and MnO-SiO 2 -CaO-Al 2 O 3 -MgO quinary systems can be reproduced within experimental uncertainties. The influence of temperature, CO partial pressure, and slag chemistry on the Mn-and Si-distribution equilibria has been quantitatively evaluated. This leads to a sound basis for optimizing the manganese ferroalloy production processes.

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Thermodynamic study of MnO-SiO2-Al2O3 slag system: Liquidus lines and activities of MnO at 1823 K

Cited by 24 publications

References 7 publications

Thermodynamics of MnO-SiO2-Al2O3-MnS Liquid Oxysulfide: Experimental and Thermodynamic Modeling

Thermodynamics of MnO-SiO2-Al2O3-MnS Liquid Oxysulfide: Experimental and Thermodynamic Modeling

Inclusions Chemistry for Mn/Si Deoxidized Steels: Thermodynamic Predictions and Experimental Confirmations

Computer simulation of equilibrium relations in managanese ferroalloy production

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