Softening–melting Properties and Slag Evolution Behavior of High Titanium Sinter

Abstract

Vanadium–titanium magnetite (VTM) is an important strategic resource, and now the process of Blast Furnace (BF) is the dominate route for smelting VTM. However, the difficulties of smelting VTM by BF inhibited further increase of VTM proportion in furnace burden due to its complex behavior in cohesive zone. The objective of this study is to reveal the softening–melting behavior of a high titanium sinter. The results indicated that the softening–melting properties of the experimental high titanium sinter were relatively worse than that of ordinary sinter due to its wider melting temperature interval and bad gas permeability in melting stage. The melting temperature interval of 225°C was obtained, and the permeability index (S value) of 1917 kPa·°C was calculated correspondingly. A second increase in pressure drop was observed in the softening–melting process, which may be ascribed to great difference of melting point between pig iron and slag. The mechanism on slag evolution was also clarified by interrupting the softening–melting process at characteristic temperatures. The XRD patterns indicated that initial slag phase mainly consisted of wustite, silicates and perovskite, of which the wustite content decreased gradually during the softening–melting process. The content of wustite was a crucial factor that affected the phase transformation during slag evolution.