The mineralogical structure of dephosphorisation slag at the first deslagging was studied by SEM–EDS, XRD and FactSage 7.0. The results show that the slag which is favourable for the enrichment of Si, Ca and P has good dephosphorisation ability. While the slag that is favourable for the enrichment of Fe and O show poor dephosphorisation ability. The main mineralogical structure in liquid slag phase is 2CaO·SiO2 and 2CaO·SiO2–3CaO·P2O5, which is favourable for dephosphorisation. The values of and increase with increasing the mole fraction of P2O5 in the solid solution phase and in the liquid slag phase, and increasing the temperature of the first deslagging. The value of increases with the increase of FeO content and slag basicity, but decreases with the increase of FeO content and basicity of solid solution phase.
Get full access to this article
View all access options for this article.
References
1.
KitamuraS.ShibataH.ShimauchiK.SatioS.: ‘Importance of dicalcium silicate on hot metal dephosphorization reaction’, Rev. Metall., 2008, 105, (5), 263–271. doi: 10.1051/metal:2008040
2.
KitamuraS.MiyamotoK.ShibataH.MaruokaN.: ‘Analysis of dephosphorization reaction using a simulation model of hot metal dephosphorization by multiphase slag’, ISIJ Int., 2009, 49, (9), 1333–1339. doi: 10.2355/isijinternational.49.1333
3.
WangZ.SunY.SridharS.ZhangM.GuoM.ZhangZ.: ‘Effect of Al2O3 on the viscosity and structure of CaO-SiO2-MgO-Al2O3-FetO slags’, Metall. Mater. Trans. B, 2015, 46, (2), 537–541. doi: 10.1007/s11663-015-0303-4
4.
ManningC. P.FruehanR. J.: ‘The rate of the phosphorous reaction between liquid iron and slag’, Metall. Mater. Trans. B, 2013, 44, (1), 37–44. doi: 10.1007/s11663-012-9757-9
5.
KitamuraS.SaitoS.UtagawaK.ShibataH.: ‘Mass transfer of P2O5 between liquid slag and solid solution of 2CaO·SiO2 and 3CaO·P2O5’, Metall. Mater. Trans. B, 2009, 49, (9), 1838.
6.
SohnI.MinD. J.: ‘A review of the relationship between viscosity and the structure of calcium-silicate-based slags in ironmaking’, Steel Res. Int., 2012, 83, (7), 611–630. doi: 10.1002/srin.201200040
7.
DeoB.HalderJ.SnoeijerB.OverboschA.BoomR.: ‘Effect of MgO and Al2O3 variations in oxygen steelmaking (BOF) on slag morphology and phosphorus distribution’, Ironmak. Steelmak., 2005, 32, (1), 54–60. doi: 10.1179/174328105X23969
8.
InoueR.SuitoH.: ‘Phosphorous partition between 2CaO·SiO2 particles and CaO-SiO2-FetO slags’, ISIJ Int., 2006, 46, (2), 174–179. doi: 10.2355/isijinternational.46.174
9.
YangX.MatsuuraH.TsukihashiF.: ‘Condensation of P2O5 at the interface between 2CaO·SiO2 and CaO-SiO2-FeOx-P2O5’, ISIJ Int., 2009, 49, (9), 1298–1307. doi: 10.2355/isijinternational.49.1298
10.
GaoX.MatsuuraH.SohnI.WangW.MinD. J.TsukihashiF.: ‘Phase relationship for the CaO-SiO2-FeO-5mass %P2O5 system with oxygen partial pressure of 10–8 atm at 1673 and 1623 K’, Mater. Trans., 2013, 54, (4), 544–552. doi: 10.2320/matertrans.M-M2013801
11.
SonP. K.KashiwayaY.: ‘Phosphorus partition in dephosphorization slag occurring with crystallization at initial stage of solidification’, ISIJ Int., 2008, 48, (9), 1165–1174. doi: 10.2355/isijinternational.48.1165
12.
YangX.MatsuuraH.TsukihashiF.: ‘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 1573 K’, ISIJ Int., 2010, 50, (5), 702–711. doi: 10.2355/isijinternational.50.702
13.
Ban-YaS.: ‘Mathematical expression of slag-metal reactions in steelmaking process by quadratic formalism based on the regular solution model’, ISIJ Int., 1993, 33, (1), 2–11. doi: 10.2355/isijinternational.33.2
14.
ShimauchiK.KitamurS.ShibataH.: ‘Distribution of P2O5 between solid dicalcium silicate and liquid phases in CaO–SiO2–Fe2O3 system’, ISIJ Int., 2009, 49, (4), 505–511. doi: 10.2355/isijinternational.49.505
15.
PahlevaniF.KitamuraS.ShibataH.MaruokaN.: ‘Distribution of P2O5 between 2CaO·SiO2-3CaO·P2O5 and liquid phase’, ISIJ Int., 2010, 50, (6), 822–829. doi: 10.2355/isijinternational.50.822
16.
LiL.SunQ.WangC.YuS.: ‘Control practice on MgO in slag of BOF’, Iron Steel, 2011, 46, (9), 40. doi: 10.1016/S1006-706X(11)60035-6
17.
LiangX. H.WangX. H.HeX. F.WangW. J.: ‘Mineral phase and untilization of semisteel slag produced during BOF double slag process’, J Iron Steel Res, 2014, 26, (10), 15–20.
18.
XieS.WangW.: ‘Isothermal crystallization study of (2CaO SiO2-3CaO P2O5) solid solution in the 45 mass% CaO-30 mass% SiO2-20 mass% FeOt-5 mass% P2O5 system at 1623 K’, Steel Res. Int., 2015, 86, (6), 1.
