Production of rutile nano-rods from Egyptian ilmenite mineral via a two-step physicochemical processes: a comparison study between low-grade and high-grade ilmenite concentrate

The synthesis of pure titanium dioxide (TiO₂) nanomaterials from naturally occurring ilmenite (FeTiO₃), which is present in black sands, is highly desirable due to its numerous industrial and technological applications. In this study, nanostructured rutile nanorods were synthesized using Egyptian ilmenite concentrate through a simple mechanical/chemical route, comprising two stages: the first stage involved the reduction of ilmenite by activated carbon as a reducing agent during milling, while the second stage involved the decomposition of FeTiO₃/carbon and the selective dissolution for  iron and silica using a mixture of HCl/H₂O₂ and NH₄F/HF, respectively. The results indicated that the optimal conditions for hydrothermal leaching of the milled ilmenite/carbon are achieved at a solid/liquid ratio of 167 g/L, 4 h at 170 °C. The amorphous titanium dioxide could be converted to ~ 95% pure rutile-phase nanorods by annealing at 700 °C followed by additional leaching processes to simply remove silica from the synthesized rutile.