Crystalline phase evolution and solid-state reaction mechanisms in high-titanium pellets during oxidation roasting

Abstract

This study aims to clarify the crystalline phase evolution and solid-state reaction mechanisms during the hardening process of high-titanium vanadium-titanium magnetite pellets. The experimental results showed that both increasing preheating-roasting temperature and extending preheating-roasting time were beneficial for the acquisition of compressive strength of preheated and roasted pellets. The pseudo-brookite exhibited preferred orientation during the preheating stage, which facilitated inter-particle bonding and improved the consolidation of preheated pellets. Subsequent roasting treatment demonstrated that pseudo-brookite developed superior microhardness characteristics, providing critical skeletal reinforcement that significantly contributed to the overall mechanical integrity of the roasted pellets. The suitable preheating parameters for high-titanium vanadium titanium magnetite were set to 900 °C for 20 min, and roasting parameters were set to 1100 °C for 20 min. Consequently, the strength of preheated and roasted pellets reached 527 and 2808 N, respectively, which could meet the actual production requirements.