Structural characteristics and viscous behaviors of Al₂O₃–CaO–SiO₂–Fe₂O₃ slags

Abstract

The high-temperature properties of the Al₂O₃–CaO–SiO₂–Fe₂O₃ basic slag had significant influences on steelmaking operations and waste slag utilization. To further clarify the structural characteristics and properties of Al₂O₃–CaO–SiO₂–Fe₂O₃ slags, the structures and viscosities of the slags were researched. The slag liquidus temperature was determined, which decreased from 1365 to 1287°C after 4.16wt%–8.52wt% Al₂O₃ was added to the slags and then increased to 1356°C after 17.07wt% Al₂O₃ was added. Structure analysis indicated that increasing temperature depolymerized the structure of the 4.16wt%Al₂O₃–CaO–SiO₂–Fe₂O₃ slag by decreasing the amount of complex AlO₄ units and promoting the formation of simplified silicate monomers. The addition of Al₂O₃ to slags could promote the polymerization of the slag structure by increasing the quantities of complex AlO₄ tetrahedral and complicated Si–O units. Variations in the degree of structure polymerization showed similar trends at the same superheat degree and the same quenching temperature, and both samples could be used for analyzing the impact of Al₂O₃ on slag structures. Finally, the viscous behavior of the present slag system was evaluated. Increasing Al₂O₃ content could increase slag viscosity, and the apparent activation energy increased from 132.13 to 174.83 kJ/mol as the content of Al₂O₃ increased from 4.16wt% to 17.07wt%.

Keywords

molten slag / alumina / structure / viscosity / spectroscopy

References

[1] LiJC, BhattacharjeeD, HuXJ, ZhangDW, SridharS, LiZS. Development of a novel process for energy and materials recovery in steelmaking slags. Miner. Process. Extr. Metall., 2017, 1261–294.

[2] WangZJ, ShuQF, SridharS, ZhangM, GuoM, ZhangZT. Effect of P₂O₅ and Fe_tO on the viscosity and slag structure in steelmaking slags. Metall. Mater. Trans. B, 2015, 462758.

[3] WangSM, KuangFH, YanQZ, GeCC, QiLH. Crystallization and infrared radiation properties of iron ion doped cordierite glass-ceramics. J. Alloys Compd., 2011, 50962819.

[4] YanZH, ZhaoQ, HanCZ, MeiXH, LiuCJ, JiangMF. Effects of iron oxide on crystallization behavior and spatial distribution of spinel in stainless steel slag. Int. J. Miner. Metall. Mater., 2024, 312292.

[5] WangZJ, SunYQ, SridharS, ZhangM, GuoM, ZhangZT. Effect of Al₂O₃ on the viscosity and structure of CaO–SiO₂–MgO–Al₂O₃–Fe_tO slags. Metall. Mater. Trans. B, 2015, 462537.

[6] ZhengRL, LüJF, SongWF, LiuMD, LiHS, LiuY, LüXJ, MaZY. Metallurgical properties of CaO–SiO₂–Al₂O₃–4.6wt%MgO–Fe₂O₃ slag system pertaining to spent automotive catalyst smelting. Int. J. Miner. Metall. Mater., 2023, 305886.

[7] MaSF, RenS, LiKJ, et al. . The effects of FeO and Fe₂O₃ on the structure and properties of aluminosilicate system: A molecular dynamics study. JOM, 2022, 74114162.

[8] ChoiJS, ParkTJ, MinDJ, SohnI. Viscous behavior of high-Fe_tO-bearing slag systems in relation to their polymeric structural units. J. Mater. Res. Technol., 2021, 15: 1382.

[9] LeeS, ChoiJS, MinDJ. Study on the relationship between sulfide capacity and viscosity of aluminosilicate slag from an ionic structural point of view. Metall. Mater. Trans. B, 2021, 5263606.

[10] HeL, LiuJH, HuT, LvTT, GaoL. Effects of Fe₂O₃ contents on molten slag viscosity behaviour. Can. Metall. Q., 2024, 6341613.

[11] J. Yang, Z. Wang, and I. Sohn, Topological understanding of thermal conductivity in synthetic slag melts for energy recovery: An experimental and molecular dynamic simulation study, Acta Mater., 234(2022), art. No. 118014.

[12] KondratievA, JakE. Predicting coal ash slag flow characteristics (viscosity model for the Al₂O₃–CaO–‘FeO’–SiO₂ system). Fuel, 2001, 80141989.

[13] WuT, WangQ, YuCF, HeSP. Structural and viscosity properties of CaO–SiO₂–Al₂O₃–FeO slags based on molecular dynamic simulation. J. Non Cryst. Solids, 2016, 450: 23.

[14] ZhangR, MinY, WangY, ZhaoX, JiaJX, LiuCJ. Viscosity estimation of multicomponent slags of the CaO–SiO₂–Al₂O₃–Fe_xO system based on microstructure analysis. Energy Fuels, 2020, 3478129.

[15] T.S. Kim and J.H. Park, Influence of Al₂O₃ and SiO2 on the structure and viscosity of iron-compound bearing calcium-aluminosilicate slags, J. Alloy. Compd., 916(2022), art. No. 165328.

[16] SongYS, HuXJ, ChouK. Effect of Al₂O₃ on viscosity and structure of CaO–SiO₂–FeO_t–(Al₂O₃)–BaO slag. Ironmaking Steelmaking, 2023, 50111521.

[17] WangBR, YangHY, JinZN, ZhengTH, ChenGB, DongZQ. Effect of Al₂O₃ on viscosity and structure of SiO₂–FeO–Al₂O₃–Fe₂O₃–CaO–MgO slag system. JOM, 2023, 7541221.

[18] KimGH, SohnI. Effect of Al₂O₃ on the viscosity and structure of calcium silicate-based melts containing Na₂O and CaF₂. J. Non Cryst. Solids, 2012, 35812–131530.

[19] Y. Hou, S. Zhang, J. Guo, H.H. Zhou, and X.W. Lv, Effects of equimolar substitution of BaO for CaO and Al₂O₃ for SiO₂ on the viscosity and structure of CaO–SiO₂–MgO–Al₂O₃–BaO slag, J. Alloy. Compd., 988(2024), art. No. 174271.

[20] ToplisMJ, DingwellDB. Shear viscosities of CaO–Al₂O₃–SiO₂ and MgO–Al₂O₃–SiO₂ liquids: Implications for the structural role of aluminium and the degree of polymerisation of synthetic and natural aluminosilicate melts. Geochim. Cosmochim. Acta, 2004, 68245169.

[21] J.H. Liu, Y.W. Yu, W.G. Kong, Q. Wang, Z.J. He, and X. Yang, Effect of Al2O3 on the molten slag microstructure information by molecular dynamics simulation and experimental analysis, J. Non Cryst. Solids, 578(2022), art. No. 121354.

[22] R.Z. Xu and Z. Wang, Effect of superheat degree and MnO on structural characteristics of CaO–SiO₂–TiO₂-based blast furnace slags, J. Non Cryst. Solids, 619(2023), art. No. 122564.

[23] R.Z. Xu and Z. Wang, Influence of TiO₂ on the liquidus temperature and structure of CaO–SiO₂–Fe₂O₃–TiO₂ slags, J. Non Cryst. Solids, 612(2023), art. No. 122357.

[24] WangZ, XuRZ. Effects of TiO₂ on the structural characteristics of CaO–SiO₂–Al₂O₃–TiO₂ glass in the same superheat state studied by Raman spectra. Ceram. Int., 2023, 491626494.

[25] StebbinsJF, DubinskyEV, KanehashiK, KelseyKE. Temperature effects on non-bridging oxygen and aluminum coordination number in calcium aluminosilicate glasses and melts. Geochim. Cosmochim. Acta, 2008, 723910.

[26] MysenBO, FrantzJD. Structure of silicate melts at high temperature: In-situ measurements in the system BaO–SiO₂ to 1669°C. Am. Mineral., 1993, 787–8699

[27] R.Z. Xu, J.L. Zhang, Z.Y. Wang, and K.X. Jiao, Influence of Cr₂O₃ and B₂O₃ on viscosity and structure of high alumina slag, Steel Res. Int., 88(2017), No. 4, art. No. 1600241.

[28] XuRZ, WangZ, SunHY, LiHX. Effect of B₂O₃ on the viscosity, structure and crystalline phase of CaO–MgO–Al₂O₃–SiO₂–MnO-based high alumina slags. Ceram. Int., 2024, 501936615.

[29] XuRZ, WangZ. Thermodynamics property and structure evolution of the TiO₂-containing molten slag with different CaO/SiO₂ ratio and TiO₂ content. Ceram. Int., 2024, 501936773.

[30] KreiselJ, LucazeauG, VincentH. Raman spectra and vibrational analysis of BaFe₁₂O₁₉ hexagonal ferrite. J. Solid State Chem., 1998, 1371127.

[31] LucazeauG, SergentN, PagnierT, ShaulaA, KhartonV, MarquesFMB. Raman spectra of apatites: La_10−xSi_6−y(Al,Fe)_yO_26±δ. J. Raman Spectrosc., 2007, 38121.

[32] R. Zhang, Z. Wang, Y.F. Meng, et al., Quantitative insight into aluminum structures in CaO–Al₂O₃–SiO₂ system via Raman and 27Al MAS-NMR spectroscopies, J. Non Cryst. Solids, 573(2021), art. No. 121116.

[33] MysenBO, FingerLW, VirgoD, SeifertFA. Curve-fitting of Raman spectra of silicate glasses. Am. Mineral., 1982, 677–8686

[34] McMillanP. Structural studies of silicate glasses and melts-Applications and limitations of Raman spectroscopy. Am. Mineral., 1984, 697–8622

[35] XuRZ, ZhangJL, HanWX, ChangZY, JiaoKX. Effect of BaO and Na₂O on the viscosity and structure of blast furnace slag. Ironmaking Steelmaking, 2020, 472168.

[36] LiuY, LvX, LiB, BaiC. Relationship between structure and viscosity of CaO–SiO₂–MgO–30.00 wt-%Al₂O₃ slag by molecular dynamics simulation with FT-IR and Raman spectroscopy. Ironmaking Steelmaking, 2018, 456492.

[37] NeuvilleDR, CormierL, MassiotD. Al coordination and speciation in calcium aluminosilicate glasses: Effects of composition determined by 27Al MQ-MAS NMR and Raman spectroscopy. Chem. Geol., 2006, 2291–3173.

[38] SohnI, WangWL, MatsuuraH, TsukihashiF, MinDJ. Influence of TiO₂ on the viscous behavior of calcium silicate melts containing 17 mass% Al₂O₃ and 10 mass% MgO. ISIJ Int., 2012, 521158.

[39] KimGH, SohnI. Influence of Li₂O on the viscous behavior of CaO–Al₂O₃–12 mass% Na₂O–12 mass% CaF₂ based slags. ISIJ Int., 2012, 52168.

[40] XuRZ, WangZ. Influence of Al₂O₃ on viscous behavior and structure characteristic of TiO₂-bearing molten slags. Ceram. Int., 2024, 501324016.

[41] XuRZ, WangZ. Research on viscosities and structural characteristics of coal slags with various Al₂O₃ contents. J. Am. Ceram Soc., 2024, 107117594.

[42] XuCY, WangC, XuRZ, ZhangJL, JiaoKX. Effect of Al₂O₃ on the viscosity of CaO–SiO₂–Al₂O₃-MgO–Cr₂O₃ slags. Int. J. Miner. Metall. Mater., 2021, 285797.

[43] KimH, KimWH, SohnI, MinDJ. The effect of MgO on the viscosity of the CaO–SiO₂–20 wt%Al₂O₃–MgO slag system. Steel Res. Int., 2010, 814261.

[44] ZhangGH, ZhenYL, ChouKC. Influence of TiC on the viscosity of CaO–MgO–Al₂O₃–SiO₂–TiC suspension system. ISIJ Int., 2015, 555922.

[45] MysenBO, VirgoD, ScarfeCM, CroninDJ. Viscosity and structure of iron- and aluminum-bearing calcium silicate melts at 1 atm. Am. Mineral., 1985, 705–6487

RIGHTS & PERMISSIONS

University of Science and Technology Beijing