固体CaO在3CaO·P_2O_5-2CaO·SiO_2饱和熔渣中的溶解及反应机理
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摘要
为了深入了解非均相脱磷剂中固体CaO在3CaO·P_2O_5-2CaO·SiO_2(C_2S-C_3P)饱和熔渣中的溶解及反应机理,采用静态浸入法和旋转圆柱法研究固体CaO在C_2S-C_3P饱和CaO-SiO_2-Fe_tO-P_2O_5(10%)渣中的溶解行为,运用FESEM/BSED-EDS对固体CaO和熔渣界面进行了观察,分析了固体CaO与C_2S-C_3P饱和熔渣间的反应机理。结果表明,加强对熔池的搅拌,能够加快固体CaO在熔渣中的侵蚀速度和溶解速度;发现了固体CaO在饱和熔渣中的溶解数量受熔渣中FeO通过边界层向固体内部渗透深度的影响,FeO渗透深度越深,溶解越多;固体CaO先与熔渣中的硅和磷反应生成磷含量低的C_2S-C_3P固溶体,待一段时间后,最终生成磷含量高的Ca_5(PO_4)_2SiO_4。
In order to deeply understand the dissolution and reaction mechanism of solid CaO in nonhomogeneous flux into 3CaO·P_2O_5-2 CaO·SiO_2(C_2S-C_3P) saturated molten slag, the dissolution test of solid CaO into C_2S-C_3P saturated CaO-SiO_2-Fe_tO-P_2O_5(10%) molten slag was carried out by applying the static dipping method and the rotating cylinder method, and the interface between solid CaO and molten slag was observed by the FESEM/BSED-EDS technique. The reaction mechanism of CaO and C_2S-C_3P saturated molten slag was analyzed. The results show that the intensive stirring within the molten pool can accelerate the erosion rate and dissolution rate of solid CaO in the slag. The dissolved amount of solid CaO into the saturated molten slag was influenced by the penetration depth into solid particles of FeO; the deeper the penetration depth, the more the dissolved amount. Solid CaO reacted firstly with the silicon and phosphorus in molten slag, generating low phosphorus C_2S-C_3P solid solution and then high phosphorus Ca_5(PO_4)_2SiO_4 after a period of time.
In order to deeply understand the dissolution and reaction mechanism of solid CaO in nonhomogeneous flux into 3CaO·P_2O_5-2 CaO·SiO_2(C_2S-C_3P) saturated molten slag, the dissolution test of solid CaO into C_2S-C_3P saturated CaO-SiO_2-Fe_tO-P_2O_5(10%) molten slag was carried out by applying the static dipping method and the rotating cylinder method, and the interface between solid CaO and molten slag was observed by the FESEM/BSED-EDS technique. The reaction mechanism of CaO and C_2S-C_3P saturated molten slag was analyzed. The results show that the intensive stirring within the molten pool can accelerate the erosion rate and dissolution rate of solid CaO in the slag. The dissolved amount of solid CaO into the saturated molten slag was influenced by the penetration depth into solid particles of FeO; the deeper the penetration depth, the more the dissolved amount. Solid CaO reacted firstly with the silicon and phosphorus in molten slag, generating low phosphorus C_2S-C_3P solid solution and then high phosphorus Ca_5(PO_4)_2SiO_4 after a period of time.
引文
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[22] Edited by Verein Deutscher Eisenheuttenleute.Slag Atlas [M].2nd Edition.Duesseldorf:Verlag Stahleisen GmbH,1995.
[23] 郭戌.转炉双联法脱磷炉石灰溶解行为研究[D]//重庆:重庆大学,2011.(Guo X.Study on Dissolution of Lime in Dephosphorization Slags by Duplex Process in Converter[D]//Chongqing:Chongqing University,2011.)
[24] Deng T,Gran J,Sichen D.Dissolution of lime in synthetic ‘FeO’-SiO2 and CaO-‘FeO’-SiO2 Slags[J].Steel Research International,2010,81(5):347.
[25] Deng T F,Du S C.Study of lime dissolution under forced convection[J].Metallurgical and Materials Transactions,2012,43B:578.
[2] Suito M,Hayashida Y,Takahashi Y.Mineralogical study of LD converter slags[J].Tetsu-to-Hagané,1977,63(8):1252.
[3] Kitamura S Y,Yonezawa K,Ogawa Y,et al.Improvement of reaction efficiency in hot metal dephosphorisation[J].Ironmaking and Steelmaking,2002,29(2):121.
[4] Uchida Y,Iwase M,Mclean A,et al.An overview on the external removal of silicon,phosphorous and sulphur from hot metal[C]//Asia Steel International Conference-2000.Beijing:The Chinese Society for Metals,2000:61.
[5] Hasegawa M,Iwase M.Thermodynamics of CaO-based slags for hot metal pretreatment[C]//Proceedings of the second baosteel biennial academic conference.Shanghai:Metallurgical Industry Press,2006:210.
[6] Zhong L C,Kusuhiro M,Masafumi Z,et al.In-situ observation of penetration of molten slag into solid lime at high temperature[J].Steel Research International,2007,78(3):236.
[7] Amini S H,Brungs M P,Jahanshahi S,et al.Effects of additives and temperature on dissolution rate and diffusivity of lime in Al2O3-CaO-SiO2 based slags[J].Metallurgical and Materials Transactions,2006,37B(5):773.
[8] 李远洲,范鹏,沈新民,等.固体石灰在转炉渣中的溶解动力学初步研究[J].钢铁,1989,24(11):22.(Li Y Z,Fan P,Shen X M,et al.Preliminary study on dissolution kinetics of CaO in converter slag[J].Iron and Steel,1989,24(11):22.)
[9] 孟金霞,陈伟庆.活性石灰在炼钢初渣中的溶解研究[J].炼钢,2008,24(2):54.(Meng J X,Chen W Q.Investigation of active lime liquation in initial slag of steel-making[J].Steelmaking,2008,24(2):54.)
[10] Umakoshi M,Mori K,Kawai Y.Dissolution rate of burnt dolomite in molten FetO-CaO-SiO2 slags[J].Transactions ISIJ,1984,24(7):532.
[11] Hamano T,Fukagai S,Tsukihashi F.Reaction mechanism between solid CaO and FeOx-CaO-SiO2-P2O5 slag at 1 573 K[J].ISIJ International,2006,46(4):490.
[12] Fukagai S,Hamano T,Tsukihashi F.Formation reaction of phosphate compound in multi phase flux at 1 573 K[J].ISIJ International,2007,47(1):187.
[13] Yang X,Matsuura H,Tsukihashi F.Condensation of P2O5 at the interface between 2CaO·SiO2 and CaO-SiO2-FeO-P2O5 slag [J].ISIJ International,2009,49(9):1298.
[14] Yang X,Matsuura H,Tsukihashi F.Reaction behavior of P2O5 at the interface between solid 2CaO·SiO2 and liquid CaO-SiO2-FeOx-P2O5 slags saturated with solid 5CaO·SiO2·P2O5 at 1 573 K[J].ISIJ International,2010,50(5):702.
[15] Ito K,Yanagisawa M,Sano N.Phosphorus distribution between solid 2CaO·SiO2 and molten CaO-SiO2-FeO-Fe2O3 slags[J].Tetsu-to-Hagané,1982,68(2):342.
[16] Inoue R,Suito H.Phosphorous partition between 2CaO·SiO2 Particles and CaO-SiO2-FetO slags [J].ISIJ International,2006,46(2):174.
[17] Suito H,Inoue R.Behavior of phosphorous transfer from CaO-FetO-P2O5(-SiO2)slag to CaO particles[J].ISIJ International,2006,46(2):180.
[18] Inoue R,Suito H.Mechanism of dephosphorization with CaO-SiO2-FetO slags containing mesoscopic scale 2CaO·SiO2 particles [J].ISIJ International,2006,46(2):188.
[19] 孙全应,张巧灵.活性石灰生产及在炼钢中的作用[J].特钢技术,2004,9(2):19.(Sun Q Y,Zhang Q L.Active lime production and its effect in the making steel process[J].Special Steel Technology,2004,9(2):19.)
[20] 刘青川.浅谈活性石灰对炼钢影响[J].一重技术,2006(1):26.(Liu Q C.Brief discussion about effect of active lime on steelmaking[J].CFHI Technology,2006(1):26.)
[21] 周进东,毕学工,杨福.液渣成分和硅酸二钙颗粒含量对铁水预处理非均相脱磷剂脱磷能力影响的试验研究[J].钢铁研究学报,2014,26(2):7.(Zhou J D,Bi X G,Yang F.Experimental study on the effect of liquid slag composition and bicalcium silicate content on the dephosphorization capacity of nonhomogeneous fluxes for hot metal pretreatment[J].Journal of Iron and Steel Research,2014,26(2):7.)
[22] Edited by Verein Deutscher Eisenheuttenleute.Slag Atlas [M].2nd Edition.Duesseldorf:Verlag Stahleisen GmbH,1995.
[23] 郭戌.转炉双联法脱磷炉石灰溶解行为研究[D]//重庆:重庆大学,2011.(Guo X.Study on Dissolution of Lime in Dephosphorization Slags by Duplex Process in Converter[D]//Chongqing:Chongqing University,2011.)
[24] Deng T,Gran J,Sichen D.Dissolution of lime in synthetic ‘FeO’-SiO2 and CaO-‘FeO’-SiO2 Slags[J].Steel Research International,2010,81(5):347.
[25] Deng T F,Du S C.Study of lime dissolution under forced convection[J].Metallurgical and Materials Transactions,2012,43B:578.