In situ observation of the dissolution kinetics of Al₂O₃ particles in CaO-Al₂O₃-SiO₂ slags using laser confocal scanning microscopy

Abstract

The dissolution kinetics of Al₂O₃ in CaO-Al₂O₃-SiO₂ slags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K. The results show that the controlling step during the Al₂O₃ dissolution was the diffusion in molten slag. It was found that the dissolution curves of Al₂O₃ particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al₂O₃ ratio of slag. A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al₂O₃ in slag. Diffusion coefficients of Al₂O₃ in slag were calculated as 2.8 × 10⁻¹⁰ to 4.1 × 10⁻¹⁰ m²/s at the temperature of 1773–1873 K. The dissolution rate of Al₂O₃ increased with higher temperature, CaO/Al₂O₃, and particle size. A new model was shown to be ${v_{{\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3}}} = 0.16 \times r_0^{1.58} \times {x^{3.52}} \times {\left( {T - {T_{{\rm{mp}}}}} \right)^{1.11}}$ to predict the dissolution rate and the total dissolution time of Al₂O₃ inclusions with various sizes, where ${v_{{\rm{A}}{{\rm{l}}_2}{{\rm{O}}_3}}}$ is the dissolution rate of Al₂O₃ in volume, µm³/s; x is the value of CaO/Al₂O₃ mass ratio; R ₀ is the initial radius of Al₂O₃, µm; T is the temperature, K; T _mp is the melting point of slag, K.

Keywords

inclusion / dissolution kinetics / confocal scanning laser microscope / refining slag

References

[1] Zhang LF, Thomas BG. State of the art in evaluation and control of steel cleanliness. ISIJ Int., 2003, 43(3): 271.

[2] Zhang LF. Non-metallic Inclusions in Steels: Industrial Practice, 2019, Beijing, Metallurgical Industry Press

[3] Zhang LF. Non-metallic Inclusions in Steels: Fundamentals, 2019, Beijing, Metallurgical Industry Press

[4] Gu C, Liu WQ, Lian JH, Bao YP. In-depth analysis of the fatigue mechanism induced by inclusions for high-strength bearing steels. Int. J. Miner. Metall. Mater., 2021, 28(5): 826.

[5] Xiao W, Bao YP, Gu C, Wang M, Liu Y, Huang YS, Sun GT. Ultrahigh cycle fatigue fracture mechanism of high-quality bearing steel obtained through different deoxidation methods. Int. J. Miner. Metall. Mater., 2021, 28(5): 804.

[6] Zhang LF, Thomas BG. State of the art in the control of inclusions during steel ingot casting. Metall. Mater. Trans. B, 2006, 37(5): 733.

[7] da Costa e Silva ALV. Non-metallic inclusions in steels — origin and control. J. Mater. Res. Technol., 2018, 7(3): 283.

[8] Wang JJ, Zhang LF, Cheng G, Ren Q, Ren Y. Dynamic mass variation and multiphase interaction among steel, slag, lining refractory and nonmetallic inclusions: Laboratory experiments and mathematical prediction. Int. J. Miner. Metall. Mater., 2021, 28(8): 1298.

[9] Jiang M, Liu JC, Li KL, Wang RG, Wang XH. Formation mechanism of large CaO-SiO₂-Al₂O₃ inclusions in Si-deoxidized spring steel refined by low basicity slag. Metall. Mater. Trans. B, 2021, 52(4): 1950.

[10] Liu Y, Zhang X, Wang P, Li DZ. Investigation on inclusions in non-oriented silicon steels. Metall. Mater. Trans. B, 2020, 51(1): 22.

[11] Zhang LF, Taniguchi S, Cai KK. Fluid flow and inclusion removal in continuous casting tundish. Metall. Mater. Trans. B, 2000, 31(2): 253.

[12] Yuan F, Xu AJ, Gu MQ. Development of an improved CBR model for predicting steel temperature in ladle furnace refining. Int. J. Miner. Metall. Mater., 2021, 28(8): 1321.

[13] Yu HX, Yang DX, Zhang JM, Qiu GY, Zhang N. Effect of Al content on the reaction between Fe-10Mn-xAl (x = 0.035wt%, 0.5wt%, 1wt%, and 2wt%) steel and CaO-SiO₂-Al₂O₃-MgO slag. Int. J. Miner. Metall. Mater., 2022, 29(2): 256.

[14] Zhang LX, Chen M, Huang MY, Wang N, Wang C. Dissolution kinetics of SiO₂ in FeO-SiO₂-V₂O₃-CaO-MnO-Cr₂O₃-TiO₂ system with different FeO contents. Metall. Mater. Trans. B, 2021, 52(4): 2703.

[15] Chen GJ, He SP, Wang Q. Dissolution behavior of Al₂O₃ into tundish slag for high-Al steel. J. Mater. Res. Technol., 2020, 9(5): 11311.

[16] Li ZR, Jia BR, Zhang YB, He SP, Wang QQ, Wang Q. Dissolution behaviour of Al₂O₃ in mould fluxes with low SiO₂ content. Ceram. Int., 2019, 45(3): 4035.

[17] Tripathi G, Malfliet A, Blanpain B, Guo MX. Dissolution behavior and phase evolution during aluminum oxide dissolution in BOF slag. Metall. Mater. Trans. B, 2019, 50(4): 1782.

[18] Park YJ, Cho YM, Cha WY, Kang YB. Dissolution kinetics of alumina in molten CaO-Al₂O₃-Fe_tO-MgO-SiO₂ oxide representing the RH slag in steelmaking process. J. Am. Ceram. Soc., 2020, 103(3): 2210.

[19] Sridhar S, Cramb AW. Kinetics of Al₂O₃ dissolution in CaO-MgO-SiO₂-Al₂O₃ slags: In situ observations and analysis. Metall. Mater. Trans. B, 2000, 31(2): 406.

[20] Liu J, Guo M, Jones PT, Verhaeghe F, Blanpain B, Wollants P. In situ observation of the direct and indirect dissolution of MgO particles in CaO-Al₂O₃-SiO₂-based slags. J. Eur. Ceram. Soc., 2007, 27(4): 1961.

[21] Park JH, Park JG, Min DJ, Lee YE, Kang YB. In situ observation of the dissolution phenomena of SiC particle in CaO-SiO₂-MnO slag. J. Eur. Ceram. Soc., 2010, 30(15): 3181.

[22] Feichtinger S, Michelic SK, Kang YB, Bernhard C. In situ observation of the dissolution of SiO₂ particles in CaO-Al₂O₃-SiO₂ slags and mathematical analysis of its dissolution pattern. J. Am. Ceram. Soc., 2014, 97(1): 316.

[23] Lee Y, Yang JK, Min DJ, Park JH. Mechanism of MgO dissolution in MgF₂-CaF₂-MF (M = Li or Na) melts: Kinetic analysis via in situ high temperature confocal scanning laser microscopy (HT-CSLM). Ceram. Int., 2019, 45(16): 20251.

[24] Sharma M, Dogan N. Dissolution behavior of aluminum titanate inclusions in steelmaking slags. Metall. Mater. Trans. B, 2020, 51(2): 570.

[25] Miao KY, Haas A, Sharma M, Mu WZ, Dogan N. In situ observation of calcium aluminate inclusions dissolution into steelmaking slag. Metall. Mater. Trans. B, 2018, 49(4): 1612.

[26] Tian TL, Zhang YZ, Zhang HH, Zhang KX, Li J, Wang H. Dissolution behavior of SiO₂ in the molten blast furnace slags. Int. J. Appl. Ceram. Technol., 2019, 16(3): 1078.

[27] Ren CY, Zhang LF, Zhang J, Wu SJ, Zhu P, Ren Y. In situ observation of the dissolution of Al₂O₃ particles in CaO-Al₂O₃-SiO₂ slags. Metall. Mater. Trans. B, 2021, 52(5): 3288.

[28] Kim Y, Kashiwaya Y, Chung Y. Effect of varying Al₂O₃ contents of CaO-Al₂O₃-SiO₂ slags on lumped MgO dissolution. Ceram. Int., 2020, 46(5): 6205.

[29] Mu WZ, Xuan CJ. Phase-field study of dissolution behaviors of different oxide particles into oxide melts. Ceram. Int., 2020, 46(10): 14949.

[30] Xuan CJ, Mu WZ. A phase-field model for the study of isothermal dissolution behavior of alumina particles into molten silicates. J. Am. Ceram. Soc., 2019, 102(11): 6480.

[31] Liu JJ, Zou J, Guo MX, Moelans N. Phase field simulation study of the dissolution behavior of Al₂O₃ into CaO-Al₂O₃-SiO₂ slags. Comput. Mater. Sci., 2016, 119, 9.

[32] Heulens J, Blanpain B, Moelans N. A phase field model for isothermal crystallization of oxide melts. Acta Mater., 2011, 59(5): 2156.

[33] Wang ZJ, Sohn I. A review of in situ observations of crystallization and growth in high temperature oxide melts. JOM, 2018, 70(7): 1210.

[34] Sohn I, Dippenaar R. In-situ observation of crystallization and growth in high-temperature melts using the confocal laser microscope. Metall. Mater. Trans. B, 2016, 47(4): 2083.

[35] Fu DC, Wen GH, Zhu XQ, Guo JL, Tang P. Modification for prediction model of austenite grain size at surface of microalloyed steel slabs based on in situ observation. J. Iron Steel Res. Int., 2021, 28(9): 1133.

[36] Tian QR, Wang GC, Shang DL, Lei H, Yuan XH, Wang Q, Li J. In situ observation of the precipitation, aggregation, and dissolution behaviors of TiN inclusion on the surface of liquid GCr15 bearing steel. Metall. Mater. Trans. B, 2018, 49(6): 3137.

[37] Wang YG, Liu CJ. Agglomeration characteristics of various oxide inclusions in molten steel containing rare earth element under different deoxidation conditions. ISIJ Int., 2021, 61(5): 1396.

[38] Mu WZ, Xuan CJ. Agglomeration mechanism of complex Ti-Al oxides in liquid ferrous alloys considering high-temperature interfacial phenomenon. Metall. Mater. Trans. B, 2019, 50(6): 2694.

[39] Zhao XJ, Yang ZN, Zhang FC. In situ observation of the effect of AIN particles on bainitic transformation in a carbide-free medium carbon steel. Int. J. Miner. Metall. Mater., 2020, 27(5): 620.

[40] Guo J, Chen XR, Han SW, Yan Y, Guo HJ. Evolution of plasticized MnO-Al₂O₃-SiO₂-based nonmetallic inclusion in 18wt%Cr-8wt%Ni stainless steel and its properties during soaking process. Int. J. Miner. Metall. Mater., 2020, 27(3): 328.

[41] Fox AB, Valdez ME, Gisby J, Atwood RC, Lee PD, Sridhar S. Dissolution of ZrO₂, Al₂O₃, MgO and MgAl₂O₄ particles in a B₂O₃ containing commercial fluoride-free mould slag. ISIJ Int., 2004, 44(5): 836.

[42] Park JH, Zhang LF. Kinetic modeling of nonmetallic inclusions behavior in molten steel: A review. Metall. Mater. Trans. B, 2020, 51(6): 2453.

[43] Lyu S, Ma XD, Huang ZZ, Yao Z, Lee HG, Jiang ZH, Wang G, Zou J, Zhao BJ. Formation mechanism of Al₂O₃-containing inclusions in Al-deoxidized spring steel. Metall. Mater. Trans. B, 2019, 50(5): 2205.

[44] Levenspiel O. Chemical Reaction Engineering, 1999, 3rd ed. the United States of America, John Wiley & Sons, Inc.

[45] Whelan MJ. On the kinetics of precipitate dissolution. Met. Sci. J., 1969, 3(1): 95.

[46] Aaron HB, Fainstein D, Kotler GR. Diffusion-limited phase transformations: A comparison and critical evaluation of the mathematical approximations. J. Appl. Phys., 1970, 41(11): 4404.

[47] Brown LC. Diffusion-controlled dissolution of planar, cylindrical, and spherical precipitates. J. Appl. Phys., 1976, 47(2): 449.

[48] F. Verhaeghe, S. Arnout, B. Blanpain, and P. Wollants, Lattice-Boltzmann modeling of dissolution phenomena, Phys. Rev. E, 73(2006), No. 3, art. No. 036316.

[49] Bale CW, Chartrand P, Degterov SA, Eriksson G, Hack K, Ben Mahfoud R, Melançon J, Pelton AD, Petersen S. FactSage thermochemical software and databases. Calphad, 2002, 26(2): 189.

[50] Mills KC, Keene BJ. Physical properties of BOS slags. Int. Mater. Rev., 1987, 32(1): 1.

[51] Ahrendts J, Kabelac S. Czichos H, Hennecke M. Technische thermodynamik. Hütte — Das Ingenieurwissen, 2012, Heidelberg, Springer Berlin, 925.

[52] Monaghan BJ, Chen L. Dissolution behavior of alumina micro-particles in CaO-SiO₂-Al₂O₃ liquid oxide. J. Non Cryst. Solids, 2004, 347(1–3): 254.

[53] Valdez M, Shannon GS, Sridhar S. The ability of slags to absorb solid oxide inclusions. ISIJ Int., 2006, 46(3): 450.