Abstract
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.
Highlights
Dephosphorization is one of the main tasks in the steelmaking process, and it is a significant problem for integrated steelmakers
Shimauchi et al [14] studied the effect of slag composition on the distribution ratio of phosphorus between the solid solution phase and the liquid slag
The results showed that the distribution ratio of phosphorus increased significantly when there was solid solution precipitation
Summary
Dephosphorization is one of the main tasks in the steelmaking process, and it is a significant problem for integrated steelmakers. The phase diagram shows that C2 S and 3CaO·P2 O5 (recorded as C3 P) can form a stable solid solution in any composition range during the temperature range of the steelmaking process. The pseudo binary phase diagram of C2 S-C3 P plotted by Fix et al [10] and the research results of Kitamura et al [16] showed that phosphorus is very stable in the C2 S-C3 P solid solution in the steelmaking temperature range. Shimauchi et al [14] studied the effect of slag composition on the distribution ratio of phosphorus between the solid solution phase and the liquid slag. By means of a high temperature experiment and SEM/EDS detection, the distribution ratio of the slag composition to phosphorus in the nC2 S-C3 P solid solution phase and liquid slag phase is systematically studied. The research results can provide a theoretical basis for the establishment of the slagging system in the converter steelmaking process, and lay a theoretical foundation for finding more effective dephosphorization methods
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
