Ionic analysis of the effect of temperature on dephosphorization capacity of silicate slags

Abstract

In order to the improvement of steel quality and dephosphorization capacity, it is vital to realize the microscopic essence of dephosphorization reaction of the slags. In this work, the temperature dependence of phosphorus distribution ratio and phosphate capacity is discussed with respect to the structure characterized by Raman and MAS-NMR. As the temperature increases from 1550°C to 1600°C, the reduction of Q0(Si) and Q0(P) weakens the formation of the Si-O-Ca-O-P linkages that can stabilize the silicate and phosphate network, which is not conducive to the increase of phosphorus distribution ratio and phosphate capacity. Meanwhile, the slight reduction of NBO/T lowers the activity of O2−, resulting that the hybrid entropy of dephosphorization reaction at 1600°C being slightly greater than that at 1550°C, indicating that the dephosphorization reaction proceeds towards the reverse direction with the increase of temperature.