Synthesis of magnetite powder from iron ore tailings

Iron ore tailing—a waste material of mineral beneficiation plants, is used as a source of iron for synthesizing magnetite powder. Iron ore tailings containing 15.98% Fe₂O₃, 83.36% SiO₂ and 0.44% Al₂O₃ have been subjected to HCl digestion on a hot plate to extract the entire amount of Fe₂O₃ as FeCl₃. A portion of extracted FeCl₃ solution has been used to convert it to FeCl₂ via metallic iron formation by using NaBH₄ as a reducing reagent. Then, the left out FeCl₃ solution and derived FeCl₂ solutions (from FeCl₃) are mixed in an appropriate molar ratio (2:1) for synthesizing magnetite powder by the addition of alkali solution. The magnetite powder samples have been characterized by means of powder XRD, SEM, vibrating sample magnetometer and laser particle size analyzer. XRD study confirms the formation of magnetite phase. The magnetite particles synthesized in different ways show varying degrees of magnetization behavior which is attributed to the change in their particle size induced by the use of different precipitating reagents.