Effect of BaSO4 on Phase Transformation and Microstructure of CaOFe2O3TiO2 System During Sintering

Abstract

The Fe₂O₃CaOTiO₂BaSO₄ system is established through miniature sintering experiments to reveal the mechanism of BaSO₄ and vanadium-titanium magnetite (VTM) with the help of X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy, and thermogravimetry. The results show that in the absence of BaSO₄, the phase of the sinter consists of CaFe₂O₄, TiO₂, Fe₂O₃, CaTiO₃, and CaFe₂O₅. When the content of BaSO₄ is 1% and 2%, CaTiO₃ decreases and the number of needle-like CF increases. Some Ba²⁺ solidly dissolve into CF and CaTiO₃ to form trace BaFe₁₂O₁₉ and BaTi₂O₅. When the content of BaSO₄ increases to 4%, the CaSO₄ phase appears, the formation of C₂F is accelerated, and the content of CF and CaTiO₃ continues to decline. The needle-like calcium ferrate gradually transforms into columnar and lamellar. As the BaSO₄ content continues to increase to 6% and 8%, although the trend of each phase is similar to that at 4%, it is almost entirely composed of columnar calcium ferrite, barium ferrite, and incomplete tetragonal and rhombic Fe₂O₃. The results of the study provide a theoretical basis for the utilization of VTM and barium-containing iron ores in practical production.