电渣重熔六元渣系FeO活度的研究

利用熔渣分子—离子共存理论,研究了电渣重熔20%CaO-20%Al_2O_3-60%CaF_2渣系在冶炼过程中,由于吸收MgO、FeO、SiO_2等夹杂物后,在渣中形成了一定浓度的FeO,而使渣系具有向钢液传递[O]的能力,考察了1 550℃下FeO、MgO质量分数以及二元碱度w(CaO)/w(SiO_2)对FeO活度的影响;分析了该渣系在1 550、1 600、1 650、1 700、1 750和1 800℃下FeO活度随温度的变化情况,构建了20%CaO-20%Al_2O_3-60%CaF_2为基础渣系的六元渣系的FeO活度的模型.研究表明:FeO活度随二元碱度w(CaO)/w(SiO_2)的增加而先增大至趋于平缓后略微减小,在碱度为3.8达到最大;FeO活度随FeO质量分数增加而线性增加,高碱度时,随FeO质量分数增加FeO活度相近;碱度为1时,FeO的活度随MgO的质量分数增加而增大,随温度升高而增加,且MgO含量越高,FeO活度越大;当碱度增加到4、7、10时,FeO的活度随MgO的质量分数增加而减小,相同质量分数的MgO时,碱度越大,FeO活度值越小;碱度为4,MgO的质量分数为1%时,FeO活度达到最大值,高碱度时,温度升高,FeO活度基本保持不变,且同一温度下,碱度越大,FeO活度反而降低.工业试验表明,该模型可以直接利用渣系对金属熔体中氧含量变化进行预测,并对减小钢液中氧含量具有指导意义.

Activity of FeO in the hexabasic slags of electroslag remelting

Based on the molecule-ion coexistence theory,owing to absorbing some inclusions like MgO,FeO and SiO2,the activities of FeO in the 20%CaO-20%Al2O3-60%CaF2 hexabasic slags for the electroslag remelting were studied. Effects of FeO,MgO and the binary basicity w(CaO)/w(SiO2) on FeO activities at 1550 ℃.Relationship between FeO activity and temperature was anyalysed at 1550,1600,1650,1700,1750 and 1800 ℃.An activity model for FeO in the hexabasic slag system was estabilished.The results showed that FeO activity first increasing, afterwards it tend to calm and finally it decrease slightly with increase of the binary basicity.The activity reaches a maximum when the binary basicity is 3.8.FeO activity increases linearly with FeO increase.FeO activity does not change with increase of FeO content when the basicity is higher.FeO activity increases with increase of MgO and temperature when the basicity is 1.0.The higher the MgO content is,the bigger the FeO activity is.When the basicity reaches 4、7 and 10,FeO activity decrease with MgO increase.When MgO content is the same, the bigger the basicity is, the samaller the FeO activity is.When the basicity is 4.0, and MgO mass fraction is 1%, FeO activity reaches a maximum.When the basicity is higher and temperature increases, FeO activity remains unchanged.At a same temperature, the higher the basicity is, the FeO activity decrease instead.The industrial test showed that the model can predict oxygen content according to slag type,it is believed that authors' model has an important practice value.