Basicity and TiO2 on Crystallization Behavior of High Ti-bearing Slag
China has abundant vanadium-titanium magnetite resources. It is important to extract Fe, Ti and V elements from vanadium-titanium magnetite by recycling. The HIsmelt smelting reduction process is an effective method to smelt vanadium-titanium magnetite. In the present study, the phase composition of high titanium slag under different temperature and different composition conditions under HIsmelt smelting reduction process was firstly analyzed by thermodynamic calculation. The experimental scheme was further designed to study the influence of different influencing factors on the crystallization behavior of high titanium slag. Thermodynamic calculation results show that perovskite and pseudobrookite are the main enrichment phases of high-titanium slag during slag phase cooling. With the increase of titanium dioxide content, the main titanium-rich phases change from perovskite to pseudobrookite. As the basicity decreases, the precipitation of the main titanium-rich phase is pseudobrookite. The experimental results are basically consistent with the thermodynamic results. With the decrease of TiO2 content, the main titanium enriched phase in the slag evolved from plate-like anosovite to columnar or dendritic perovskite, and the size of precipitated crystals decreases. When the content of TiO2 decreases to 23%, the precipitation morphology of some perovskite crystals changes from columnar to dendritic. As the basicity of slag decreases, the titanium-rich phase in slag changes from perovskite to anosovite. When the basicity of slag is 0.8, anosovite becomes the only titanium-rich phase. The anorthite grows in a thin rod shape. In addition, with the decrease of MgO/Al2O3 ratio, the composition of anosovite changes from (MgTi2O5)0.8/(Al2TiO5)0.2 becomes (MgTi2O5)0.6/(Al2TiO5)0.4. The research results provide a reference for further understanding of the crystallization behavior of high-titanium slag produced by HIsmelt smelting reduction process and the utilization of titanium-rich slag as a resource.