Magnetite powder and kaolinite derived from waste iron ore tailings for environmental applications

The present study demonstrated a feasible approach of utilizing waste iron ore tailings in synthesis of value added products for environmental applications. The ferric iron recovered from waste iron ore tailings via acid leaching followed by precipitation as ferric (hydr)oxide was used as feed stock to synthesis magnetite powder by its reductive-roasting with charcoal. Physicochemical characterizations revealed the formation of sufficiently pure magnetite powder with ferric (hydr)oxide to charcoal ratio 1:2 and calcined at 1200 °C for 4 h. The magnetic powder as such or coated with polyacrylic acid, was found efficient for removal of a model dye, methylene blue from its solution within 2 min. The acid insoluble residue, generated after iron recovery from iron ore tailings, was characterized as kaolinite. The residue with reasonably good surface area (119 m2 g− 1) was also found effective for adsorptive removal of dyes including methylene blue and can find large scale applications in wastewater treatment. Moreover the present study provided further inputs for possible alternative uses of waste iron ore tailings to partly reduce its associated disposal problems.