Effect of high-pressure grinding rolls pretreatment on the preparation of vanadium-titanium magnetite pellets

Abstract

To solve the problems of low consolidation strength and high energy consumption of vanadium-titanium magnetite (VTM) pellets, high-pressure grinding rolls (HPGR) technology can be used to pretreat the raw materials (VTM concentrate). Compared with other technologies, HPGR pretreatment has the advantages of high efficiency and low energy consumption. This study discovered that the quantities of titaniferous magnetite particles with coarse size and regular shape were dominant in VTM concentrate. Lower surface area resulted in lower microcrystalline and recrystallization bonding strength of titaniferous hematite in VTM pellets. In this study, HPGR pretreatment technology was used in the preparation of VTM pellets. Experiments confirmed that the high pressure supplied by HPGR could increase the total contact area between particles in VTM pellets, which was conducive to form more microcrystalline and recrystallization connections of titaniferous hematite. The performance of VTM green pellets was greatly improved by HPGR pretreatment, the preheating temperature could be reduced about 100 °C, the roasting temperature could be decreased 60–80 °C, the preheating and roasting time could also be correspondingly shortened. These research results will provide important insights to solve the problems of low strength and high energy consumption of VTM pellets.

Keywords

• Vanadium-titanium magnetite
• HPGR
• Pellets
• Microstructure
• Consolidation strength