单渣法转炉终渣理化性质对脱磷的影响研究

Effect of Physicochemical Properties of Single Slagging Converter Final Slag on Dephosphorization

在转炉利用单渣法冶炼HRB500E钢种的过程中,转炉终渣的性质对终点钢液磷含量有着直接的影响。以单渣高拉碳低磷冶炼工艺生产HRB500E钢种得到的转炉终渣为研究对象,通过采用XRD、SEM、EDS及热力学软件Factsage8.1,结合高温熔点实验研究了转炉渣的矿相结构、熔化温度和黏度等理化性质对转炉脱磷的影响。研究结果表明:终渣中的硅酸二钙相和磷酸三钙相有利于脱磷反应的进行;终渣的黏度随着温度的升高而降低,降低终渣的黏度和熔化温度有利于脱磷反应的进行;将终渣碱度控制在2.8~2.9,w(FeO)控制在15.9%~18.3%,终渣的熔化温度控制在1357℃以下,可以实现终点出钢w(P)<0.020%,终点脱磷率大于82%。

During the smelting of HRB500E steel grade in converter using single slagging,the properties of converter final slag has a direct influence on the phosphorus content of the end molten steel.The influence of the physicochemical properties of the converter slag such as mineral phase structure,melting temperature and viscosity on the converter dephosphorization was investigated by XRD,SEM,EDS,and the thermodynamic software Factsage 8.1,combined with high temperature melting point experiments.The results show that:the dicalcium silicate phase and tricalcium phosphate phase in the final slag are beneficial to the dephosphorization reaction;the viscosity of the final slag decreases with the increase of temperature,and reducing the viscosity and melting temperature of the final slag is beneficial to the dephosphorization reaction;controlling the alkalinity of the final slag at 2.8%~2.9%,the w(FeO)at 15.9%~18.3%,and the melting temperature of the final slag at 1357℃or below can achieve the end point.The phosphorus content of the steel is less than 0.020,and the end-point dephosphorization rate is greater than 82%.