Recovering titanium and iron by co-reduction roasting of seaside titanomagnetite and blast furnace dust

Co-reduction roasting of seaside titanomagnetite and blast furnace dust was investigated to maximize the use of these ores in Indonesia. This direct reduction process utilizes fixed carbon in BFD to reduce iron from BFD and titanomagnetite. X-ray diffraction and X-ray fluorescence analyses were performed to characterize the reduced iron powder. The influences of reduction conditions, such as reduction temperature and duration, C/Fe molar ratio, grinding fineness and fluorite dose, on the indicators of reduced iron powder were evaluated. Fixed carbon and volatile matter contents were lower in BFD than those in coal. However, reduction and separation of titanium and iron exhibited similar effects on reduction roasting. Results showed that the optimum conditions of roasting reduction included C/Fe molar ratio of 0.65, fluorite dose of 4 mass%, and roasting temperature of 1300 °C for 60 min. The reduced iron powder was obtained through two-stage grinding and two-stage magnetic separation of the roasted product. The former contained 94.23 mass% Fe and 0.58 mass% TiO₂ and showed total iron recovery of 87.62%. The latter contained 19.72 mass% Fe and 25.47 mass% TiO₂, thereby providing prerequisites for titanium recycling.