Effect of MgO and SiO₂ on surface tension of fluoride containing slag

Abstract

Surface tensions of slag addition MgO and SiO₂ based on conventional 70%CaF₂-30%Al₂O₃ and 60%CaF₂-20%CaO-20%Al₂O₃ (mass fraction) at 1300 °C, 1400 °C and 1500 °C were investigated. Influence mechanism of MgO and SiO₂ on slag surface tension was also analyzed. Results indicate that surface tension decreases with the increase of MgO content in the case of the MgO content (mass fraction) less than 8%, however, when MgO content (mass fraction) is from 8% to 30%, surface tension increases with the increase of MgO content. When SiO₂ content (mass fraction) is from 2% to 8%, surface tension decreases with the increase of SiO₂ content. Additionally, the relationship between surface tension and optical basicity is a monotonically increasing linear function. Research findings can provide important reference for slag design and the study of slag-metal interfacial tension.

Keywords

electroslag metallurgy / fluoride containing slag / surface tension / influence mechanism

References

[1] MitchellA. Solidification in remelting processes [J]. Materials Science and Engineering A, 2005, 413-414: 10-18

[2] YoonB H, HeoK H, KimJ S, SohnH S. Improvement of steel cleanliness by controlling slag composition [J]. Ironmaking and Steelmaking, 2002, 29(3): 215-218

[3] NakamotoM, HanaoM, TanakaT, KawamotoM, HolappaL, HamalainenM. Estimation of surface tension of molten silicates using neural network computation [J]. ISIJ International, 2007, 47(8): 1075-1081

[4] ParkS C, GayeH, LeeH G. Interfacial tension between molten iron and CaO-SiO₂-MgO-Al₂O₃-FeO slag system [J]. Ironmaking and Steelmaking, 2009, 36(1): 3-11

[5] SeoS M, PaikY H, KimD S, LeeW P. Interfacial tension and contact angle variations of SUS304 melt in contact with solid oxides and CaO-SiO₂-Al₂O₃(CaF₂) slags at 1470 °C [J]. Metals and Materials, 1996, 2(2): 65-69

[6] ChoiJ Y, LeeH G. Thermodynamic evaluation of the surface tension of moltenCaO-SiO₂-Al₂O₃ ternary slag [J]. ISIJ International, 2002, 42(3): 221-228

[7] NakamotoM, KiyoseA, TanakaT, HolappaL, HämäläinenM. Evaluation of the surface tension of ternary silicate melts containing Al₂O₃, CaO, FeO, MgO or MnO [J]. ISIJ International, 2007, 47(1): 38-43

[8] HeikkinenE P, RiipiJ, FabritiusT, PajarreR, KoukkariP. Computational modelling of oxide surface tensions in secondary metallurgy and continuous casting [J]. Steel Research International, 2010, 81(11): 959-964

[9] TanakaT, KitmuraT, BackI A. Evaluation of surface tension of molten ionic mixtures [J]. ISIJ International, 2006, 46(3): 400-406

[10] AllibertM, GayeH, GeislerJ, JankeD, KeeneB J, KirnerD, KowalskiM, LehmannJ, MillsK C, Neuschütz, ParraR, Saint-JoursC, SpencerP J, TmarM, WoermannESlag atlas [M], 19952nd. edDusseldorf, German Sreel Association: 415-424

[11] HanaoM, TanakaT, KawamotoM, TakataniK. Evaluation of surface tension of molten slag in multi-component systems [J]. ISIJ International, 2007, 47(7): 935-939

[12] YuR-b, ZhangZ-x, MaoY-wen. Study on surface tension and slag-steel interface tension of CaF₂-CaO-MgO-Al₂O₃-SiO₂ slags for ESR process [J]. Journal of Iron and Steel Research, 1989, 1(3): 15-19

[13] DouZ-h, ZhangT-a, YaoJ-m, NiuL-p, JiangX-l, HeJ-cheng. Research on properties of CaF₂-CaO-Al₂O₃-MgO-SiO₂ refining slag [J]. The Chinese Journal of Process Engineering, 2009, 9(1): 132-136

[14] StrandhJ, NakajimaK, ErikssonR, JönssonP. Solid inclusion transfer at a steel-slag interface with focus on tundish conditions [J]. ISIJ International, 2005, 45(11): 1597-1606

[15] WangC-zhenResearch methods in metallurgical physical chemistry [M], 19822nd. edBeijing, Metallurgical Industry Press: 331

[16] NakamuraT, UedaY, JamesM. A new development of the optical basicity [J]. Journal of the Japan Institute of Metals, 1986, 50(5): 456-461

[17] ElfsbergJ, MatsushitaT. Measurements and calculation of interfacial tension between commercial steels and mould flux slags [J]. Steel Research International, 2011, 82(4): 404-414

[18] JungE J, MinD J. Effect of Al₂O₃ and MgO on interfacial tension between calcium silicate-based melts and a solid steel substrate [J]. Steel Research International, 2012, 83(7): 705-711

[19] JungE J, KimW, MinD J. A study on the interfacial tension between solid iron and CaO-SiO₂-MO system [J]. Journal of Material Science, 20102023-2029

[20] MatsushitaT, WatanabeT, HayashiM, MukaiK. Thermal, optical and surface/interfacial properties of molten slag systems [J]. International Materials Reviews, 2011, 56(5/6): 287-323

[21] HaraS, OginoK. Density and surface tension of melts in the CaF₂-CaO-SiO₂ system [J]. Journal of the Iron and Steel Institute of Japan, 1989, 75(3): 439-445