Distribution Behavior of Phosphorus in 2CaO·SiO2-3CaO·P2O5 Solid Solution Phase and Liquid Slag Phase

• Published in: Metals (Basel ) 2020-08, Vol.10 (8), p.1103
• Main Authors: Zhu, Bin, Zhu, Mingmei, Luo, Jie, Dou, Xiaofei, Wang, Yu, Jiang, Haijun, Xie, Bing
• Format: Article
• Language: English
• Subjects: Activity coefficients; Basicity; CaO-SiO2-FetO-P2O5 slag system; Composition effects; dephosphorization; Dephosphorizing; distribution ratio of phosphorus; Experiments; High temperature; High temperature effects; Iron; n·2CaO·SiO2-3CaO·P2O5 solid solution; Phosphorus; Phosphorus pentoxide; Silicon dioxide; Slag; Solid solutions; Steel converters
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met10081103

In this paper, the CaO-SiO2-FetO-P2O5 dephosphorization slag system during the premier and middle stage of the converter process was studied, the effect of slag composition on the distribution ratio and activity coefficient of P in the n·2CaO·SiO2-3CaO·P2O5 (recorded as nC2S-C3P) solid solution phase and liquid slag phase in the slag system was studied used by the high temperature experiment in laboratory, the theoretical calculation of thermodynamics, and the scanning electron microscope and the energy dispersive spectrometer (recorded as SEM/EDS). The research results show that when the FeO content in the liquid slag increases from 32.21% to 50.31%, the distribution ratio of phosphorus (recorded as LP) in the liquid slag phase increases by 3.34 times. When the binary basicity in the liquid slag increases from 1.08 to 1.64, the LP in the liquid slag phase decreases by 94.21%. In the initial slag, when the binary basicity increases from 2.0 to 3.5, the LP decreases by 70.07%. When FeO content increases from 38.00% to 51.92%, the LP increases by 6.15 times. When P2O5 content increases from 3.00% to 9.00%, the LP increased by 10.67 times. When the FeO content in the liquid slag increases from 32.21% to 50.31%, the activity coefficient of P2O5 in the liquid slag phase (recorded as γP2O5(L)) increases by 54.33 times. When the binary basicity in the liquid slag increases from 1.08 to 1.64, γP2O5(L) decreases by 99.38%. When the binary basicity increases from 2.0 to 3.5, the activity coefficient of P2O5 in the solid solution phase (recorded as γP2O5(SS)) in the solid solution phase decreases by 98.85%. When P2O5 content increases from 3.00% to 9.00%, γP2O5(SS) increases by 1.14 times. When the binary basicity decreases from 3.5 to 2.0, n decreases from 0.438 to 0.404. When the FeO content increases from 38.00% to 51.92%, n decreases from 0.477 to 0.319. When the P2O5 content increases from 3.00% to 9.00%, n decreases from 0.432 to 0.164. The decrease of binary basicity and the increase of FeO and P2O5 content in the initial slag can reduce the value of n and enrich more phosphorus in the solid solution phase. The results can not only provide a theoretical basis for industrial production, but also lay a theoretical foundation for finding more effective dephosphorization methods.