Microstructure and Viscosity of Dephosphorization Slag in New Double Slag Converter Steelmaking Process

Abstract

The structure and viscosity of the dephosphorization slag in new double slag converter steelmaking process with low basicity slag at the low temperature range of 1 573 K-1 723 K are studied with hightemperature laboratorial experiments. With increasing the end temperature of dephosphorization, the viscosities of different slags decrease rapidly at first, then decrease slowly, and the slag activation energies increase. The values of Non-Bridging Oxygen per Silicon (NBO/Si) decrease, indicating the increase in the degree of polymerization (DOP) of the dephosphorization slag and the viscous flow activation energy of the dephosphorization slag. The results of Raman and FTIR spectroscopy are consistent. The dephosphorization slag in the temperature range of 1 573 K-1 673 K is mainly composed of the P-rich region, Fe-rich region and liquid region. With increasing temperature from 1 573 K to 1 673 K, the proportion of the liquid region in slag increases, but the P-rich and Fe-rich regions correspondingly decrease.