转炉铁水预处理脱磷的影响因素

Dephosphorization influence factors in converter hot metal pretreatment

基于炉外铁水深度预脱硫+转炉铁水预脱磷的铁水预处理工艺是当今低磷或超低磷钢冶炼的重要工艺平台,其中转炉铁水预处理脱磷是关键的技术环节。以国内"双联转炉炼钢法"预脱磷炉实践为出发点,在实验室高温炉上通过顶加脱磷剂、浸入吹氧进行了铁水模拟转炉预脱磷影响因素的试验研究,比较了铁水温度、铁水初始硅质量分数w(Si)i、脱磷渣碱度、供氧制度、搅拌强度、萤石加入量对脱磷效率的影响。结果表明,各因素对脱磷率影响的顺序为铁水温度>w(Si)i>供氧制度>脱磷渣碱度、搅拌强度>萤石加入量;适宜的工艺参数为铁水温度为1300℃,w(Si)i为0.10%~0.26%或低于0.30%,脱磷渣碱度为2.9~3.0,供氧制度中气氧与固氧各占50%或固氧稍偏多,维持较高的搅拌强度;转炉内铁水预脱磷处理可不加萤石。

Dephosphorization of hot metal pretreatment in the converter is nowadays playing an important role in the production of low or super low phosphorus steel grades.Based on the pretreatment dephosphorization converter practice in"duplex converter steelmaking"process in domestic iron and steel enterprises,experimental studies on dephosphorization influence factors in converter hot metal pretreatment were imitatively carried out by top addition of dephosphorization agent and immersed blowing of gaseous oxygen in SiC electric resistance furnace of molten pig iron.The effects of different hot metal temperature,initial silicon content in hot metal w(Si)_i,slag basicity,oxygen supply(the ratio of gaseous oxygen and total oxygen),stirring strength,and fluorspar addition on dephosphorization efficiency are compared.The results showed that the ranking order of different factors affecting dephosphorization ratio is hot metal temperature>w(Si)_i>oxygen supply>slag basicity,stirring strength>fluorspar addition,the appropriate process parameters are the hot metal temperature of 1300℃,w(Si)_iof 0.10%-0.26%or less than 0.30%,slag basicity of 2.9 to 3.0,oxygen supply of 50%solid oxygen or a few more,and with stronger stirring,and the dephosphorization agent is probable without fluorspar during hot metal dephosphorization pretreatment in the converter.