复吹转炉“留渣 双渣”脱磷工艺试验

摘要：在国内某转炉钢厂采用“留渣 双渣”工艺技术进行脱磷工艺试验。结果表明：随着转炉前期脱磷率不断升高，终点脱磷率不断提高。铁水硅含量对前期脱磷率的影响最大。根据铁水成分，在冶炼前期适当降低供氧强度、降低气固氧比、加入适量石灰及烧结矿，均有利于前期脱磷率的提高。在一倒时每吨钢液加入4~8kg石灰，不影响出钢温度，可提高一倒-终点阶段脱磷率，同时可提高终点脱磷率。从终点的控制效果可知，终点炉渣碱度应保持不小于3.0，炉渣中FeO质量分数在16%~20%，并适当降低终点出钢温度在1610~1630℃，有利于终点脱磷率的提高。通过加强熔池搅拌，促进钢渣反应趋于平衡，有利于终点磷分配比提高，从而可进一步提高终点脱磷率。

Experiment on dephosphorization process of “remaining slag double slag” in combined blown converter

Abstract： The dephosphorization process test was carried out in a domestic converter steel plant by using the “remaining slag double slag” process technology. The results show that with the increasing of dephosphorization rate in early stage of converter, the end point dephosphorization rate increases continuously. The silicon content in molten iron has the greatest influence on the dephosphorization rate in early stage. According to the composition of molten iron, properly reducing the oxygen supply intensity, reducing the gas solid oxygen ratio，adding an appropriate amount of lime and sinter in early stage of smelting are conducive to the improvement of dephosphorization rate in early stage. Adding lime of 4-8kg per ton of molten steel in the first turn down stage does not affect the tapping temperature, which can improve the dephosphorization rate in the first turn down to end point stage and the end point dephosphorization rate at the same time. From the control effect of the end point, the alkalinity of the end point slag should not be less than 3.0, the mass fraction of FeO in the slag should be 16%-20%, and the end point tapping temperature should be appropriately reduced to 1610-1630℃, which is conducive to the improvement of the end point dephosphorization rate. By strengthening of the stirring of molten pool and promoting the balance of the steel slag reaction, it is conducive to improvement of the end point phosphorus distribution ratio, so as to further improve the end point dephosphorization rate.