Effect of Sinter Return Ore Addition on Dephosphorization Behaviour of Hot Metal

Abstract

：In order to make better use of sinter return ore and iron oxide scale to achieve effective pre-dephosphorization of molten iron, the effects of final slag morphology, mineral phase structure and polymerization degree on pre-dephosphorization were studied by theoretical analysis, XRD, SEM-EDS, Raman and FTIR spectra. The results show that when the proportion of sinter return ore is less than 20%, the impact on dephosphorization is relatively small. The structural analysis of dephosphorization final slag shows that the increase of sinter return ore will lead to the decrease of phosphorus content in phosphorus-rich phase and the increase of RO phase and iron-rich phase in slag. O 2destroys P-O-P bond more than Si-O-Si bond. When the phosphorus entering the slag decreases, the content of Q 0 (Si) structure decreases, and silicon tends to exist in the form of higher polymerization degree. With the increase of the proportion of sinter return ore, the structure of [FeO 6 ] 9in slag increases, which is not conducive to the migration of phosphorus. When the oxidant is only sinter return ore, the proportion of Q 1 (Si) and P-O-Si structure in slag increases obviously, and the evolution of silicate structure is the main reason for the change of polymerization degree of slag. This study can provide theoretical reference and technical basis for the effective utilization of sinter return ore and the reduction of production cost in iron and steel enterprises.