含铬镍铁水脱磷保铬的机理与试验

 为了解决铬镍生铁因磷质量分数高用做不锈钢原料受限的问题，开展了关于含铬镍铁水脱磷保铬的理论计算和工业试验研究。采用竖炉工艺回收不锈钢粉尘，冶炼出的含铬镍铁水磷质量分数高，导致铁水利用量受限。通过计算铬、镍、铁氧化物还原热力学条件和磷、铬、碳氧化的临界氧势，提出了采用碱性CaO渣系、控制炉渣氧势和出铁温度实现脱磷保铬的措施。在理论计算基础上，进行了竖炉冶炼含铬镍铁水的脱磷保铬工业试验。试验共冶炼出含铬镍铁水32 t，当炉渣碱度为1.15、炉渣[w(FeO)]为4.98%、出铁温度为1 673～1 684 K时，脱磷率可达36%以上，铁水中磷质量分数可降至0.023%，铬收得率为88%以上，本研究达到了脱磷保铬的目的，并且解决了含铬镍铁水磷质量分数高的问题。

Mechanism and experimental for dephosphorizion and chromium conservation of chromium containing melted iron

To solve the problem on the iron utlizion limition as high P，calculation and industry test on dephosphorization and chromium conservation of iron with Cr and Ni was studied，so as stainless steel dust could be recycled by the process of shaft furnace. But the liquid iron smelted by this process had the problem of high phosphorus content， which then led to the use of liquid iron restricted. For realizing dephosphorization and chromium conservation of liquid iron， through calculation， including thermodynamic conditions of the reduction of chrome， nickel and iron oxide and the critical oxygen potentials of phosphorus， chromium and carbon oxidized， three measures were put forward. The measures were using CaO alkaline slag series， controlling oxygen potential and tapping temperature. On the basis of the theoretical calculation， experimental study about dephosphorization and chromium conservation of chromium-nickel containing liquid iron which was smelted by shaft furnace， was carried out in industry. 35 t of chromium-nickel containing liquid iron was smelted in experiment. The results show that when the slag basicity is 1.15， the content of FeO in slag is controlled at about 5%， the tapping temperature is controlld within 1 673-1 684 K， dephosphorization rate could be reached to more than 36%， content of phosphorus in molten iron could be dropped to 0.023%， and Cr yield is over 88%. Experiment indicates that the purpose of dephosphorization and chromium conservation could be achieved by using the measures studied， and the problem of high phosphorus content in liquid iron containing chromium and nickel could be solved.