气化脱磷机理及对下炉次冶炼过程的影响研究

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

为了解决转炉渣由于磷含量过高而不能返回到转炉内循环利用的问题,采用FactSage7.2并结合SEM+EDS对气化脱磷理论和影响因素、留渣操作和枪位控制对脱磷的影响以及气化脱磷渣形貌进行了分析。结果表明,在温度高于941 K时用C还原出炉渣中P_2O_5的P是可行的,同时降低反应分压有利于气化脱磷反应的进行;采用焦粉作为还原剂时,碳当量和底吹流量分别控制为2倍碳当量和300 m^3/h时气化脱磷效果最好;当底吹流量为300 m^3/h、2倍碳当量和w(FeO)≥18%时气化脱磷率最高,为42%。采用留渣操作溅渣护炉气化脱磷模式时终点钢液磷含量较低,前期采用稍高的吹炼枪位,后期逐渐降低枪位,气化脱磷渣形貌结构表明P元素主要富集在Ca、Si所在的深灰色区域。

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 m3/h,respectively.Gasification dephosphorization rate can reach a maximum value of 42% when bottom blowing flow,carbon equivalent,FeO content are 300 m3/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.