Study on Mechanism of Gasification Dephosphorization and Influence of Next Heat Smelting Process

In order to solve the problem that BOF slag can not be returned back into BOF due to its high P content,the dephosphorization mechanism of gasification and influencing factors,effect of slag remaining operation and lance controlling on dephosphorization,and morphology of gasification dephosphorization slag were analyzed by FactSage7.2 and SEM+EDS in this paper.The result shows that it is feasible to use C to reduce P of P₂O₅ for slag when temperature exceeding 941 K,and it is beneficial to the gasification dephosphorization reaction by reducing the reaction partial pressure.While taking coke powder as a reducing agent,the best results of gasification dephosphorization were obtained when the carbon equivalent and bottom blowing flow were controlled at 2 times the carbon equivalent and 300 m~3/h,respectively.Gasification dephosphorization rate can reach a maximum value of 42% when bottom blowing flow,carbon equivalent,FeO content are 300 m~3/h、2 times and≥18%.When using slag remaining operation for gasification dephosphorization mode of splashing furnace protection,where higher blowing lance operation at the early stage and gradually lower high and low blowing lance operation at later stage,the phosphorus content of molten steel at the end is relatively low.SEM observation on morphology structure of gasification dephosphorizationslag indicated that P mainly concentrated in enriched Ca and Si areas.