Kinetics of MgO Reduction in CaO-Al2O3-MgO Slag by Al in Liquid Fe
Abstract
:1. Introduction
2. Model Description
2.1. Single Control Model
2.2. Mixed Control Model
3. Experimental Method
4. Results and Discussion
4.1. Model Predictions and Effect of Correlative Condition
4.2. Comparison Analysis of Experiment and Model Results
5. Conclusions
- Due to the slow mass transport in the slag, the reaction rate in the mixed control model was always lower than that in the single control model.
- Higher initial [Al] content in the steel and (MgO) content in the slag led to the increase of equilibrium concentrations of [Mg] in the steel and (Al2O3) in the slag, and also improved the reaction rates in both kinetic models.
- In the single control model, (Al2O3) and (MgO) contents in the bulk slag were the same as those at the steel–slag interface, while differences between the bulk and interface concentrations of (Al2O3) and (MgO) were observed in the mixed control model, which resulted in the mass transportation of the slag components being an extra rate-limiting step.
- The mass transfer coefficient of [Mg] in the steel was computed to be 6.2 × 10−5 m·s−1 according to the experimental equilibrium results between an Fe-1.0 mass% Al steel and 51 mass% CaO-39 mass% Al2O3-10 mass% MgO slag at 1873 K (1600 °C). Using this value, the mixed control model was validated at different initial Al levels in the steels.
- Experimental results with the model predictions confirmed that the mass transport in the slag should be given full consideration during the kinetics analysis of MgO reduction reaction.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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No. | Chemical Compositions of the Steels/Mass% | Slag Composition/Mass% | |||||
---|---|---|---|---|---|---|---|
C | Al | S/ppm | Mg/ppm | CaO | Al2O3 | MgO | |
1 | 5 | 0.1 | 10 | 3 | 51 | 39 | 10 |
2 | 5 | 1 | 10 | 3 | |||
3 | 5 | 2 | 10 | 3 |
Model Parameter | Value | Model Parameter | Value |
---|---|---|---|
[%Al]b (t = 0) | 0.5 mass% | Mass transfer coefficient of Al in steel, | 1 × 10−4 m·s−1 [21] |
[%Mg]b (t = 0) | 3 × 10−4 mass% | Mass transfer coefficient of Mg in steel, | 1 × 10−4 m·s−1 [21] |
[%Al2O3]b (t = 0) | 39.0 mass% | Mass transfer coefficient of Al2O3 in slag, | 1 × 10−5 m·s−1 [13,22] |
[%MgO]b (t = 0) | 10.0 mass% | Mass transfer coefficient of MgO in slag, | 1 × 10−5 m·s−1 [13,22] |
[%CaO]b (t = 0) | Balanced | Experiment temperature, | 1873 K (1600 °C) |
−0.13 [6] | Reaction area between the steel and slag, A | π·(0.03)2 m2 | |
0.043 [6] | Density of steel, | 7000 kg·m−3 | |
0.27 [6] | Density of slag, | 3000 kg·m−3 | |
0 [6] | Weight of steel, | 500 g | |
K (1873 K) | 9.74 × 10−11 [6] | Weight of slag, | 75 g |
Time/min | 0 | 5 | 10 | 15 | 20 | 25 | 30 |
---|---|---|---|---|---|---|---|
[%Mg]b/ppm | 3 | 32.6 | 52.2 | 51.5 | 47.7 | 57.3 | 58.5 |
[%Al]b/mass% | 1.0 | 0.98 | 0.97 | 0.92 | 0.94 | 0.92 | 0.9 |
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Liu, C.; Liu, X.; Yang, X.; Zhang, H.; Zhong, M. Kinetics of MgO Reduction in CaO-Al2O3-MgO Slag by Al in Liquid Fe. Metals 2019, 9, 998. https://doi.org/10.3390/met9090998
Liu C, Liu X, Yang X, Zhang H, Zhong M. Kinetics of MgO Reduction in CaO-Al2O3-MgO Slag by Al in Liquid Fe. Metals. 2019; 9(9):998. https://doi.org/10.3390/met9090998
Chicago/Turabian StyleLiu, Chengsong, Xiaoqin Liu, Xiaoliu Yang, Hua Zhang, and Ming Zhong. 2019. "Kinetics of MgO Reduction in CaO-Al2O3-MgO Slag by Al in Liquid Fe" Metals 9, no. 9: 998. https://doi.org/10.3390/met9090998