Isothermal Carbothermal Reduction of FeTiO₃ Doped with MgO

The effect of MgO on the carbothermal reduction of FeTiO₃ has been investigated using isothermal experiments. x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) techniques were used to reveal the reduction mechanism of FeTiO₃ doped with MgO. The results showed that MgO could promote the reduction of FeTiO₃. After doping with MgO, solid solution of Mg²⁺ in the FeTiO₃ unit cell formed a new phase (Fe_1–x,Mg_x)₂TiO₄. With increase of the MgO content, the stability of the FeTiO₃ lattice and the (Fe_1–x,Mg_x)₂TiO₄ structure decreased while the reaction activity increased, facilitating formation of FeTi₂O₅ and (Fe_1–2x,Mg_2x)TiO₃ and aiding reduction of (Fe_1–x,Mg_x)₂TiO₄ to the orthogonal system (Fe_1–2x,Mg_2x)TiO₃. When the content of MgO exceeded 4%, large amounts of magnesium–titanium compounds were generated and subsequently covered unreacted particles. Meanwhile, the contact area between unreacted particles and reducing agents decreased, thereby weakening the promoting effect of MgO.