Simplified hydrometallurgical route for the synthesis of silica-free hematite from iron ore tailings

The processing of iron ore generates large volumes of tailings. Acid leaching enables the solubilization of iron in an aqueous solution, allowing the production of ferric liquor and a silica-rich residue. The purpose of this investigation was to use the leachate resulting from this process to synthesise high-quality iron oxide. The conducted methodology involved acid leaching, selective iron precipitation as a function of pH, and the thermal conversion of the precipitated iron oxy-hydroxides into iron oxide particles. The iron oxide consisted of micro/nano Fe2O3 particles which were free of silica, with iron contents of 64% and particle sizes of less than 28 μm. The process presented an overall iron recovery around 84%. The resulting material could be used as a commercial pigment or be incorporated into steel-making iron pellets. The hydrometallurgical conversion of iron ore wastes into valuable products may contribute to the future of mining and to green steel production.