Iron Ore Tailings Reprocessing by Electrostatic Separation Plus Two-Stage Froth Flotation

The reprocessing of tailings is crucial for recovering valuable iron and reducing the environmental impact associated with tailings disposal. The raw iron ore tailings used in this study had an initial iron oxide content of 24.05 wt% Fe2O3, as determined by ICP-OES analysis. This study investigates the practicality of tailings reprocessing to enhance iron oxide content by integrating electrostatic separation with a two-stage froth flotation process consisting of direct anionic flotation using oleic acid followed by reverse cationic flotation using amine collectors. The primary goal is to efficiently recover valuable iron from tailings, thereby reducing waste and promoting sustainable resource utilization. The process aims to upgrade the iron oxide content above 93 wt% Fe2O3, making the recovered material suitable for direct-reduced iron production. Electrostatic separation was first employed as a pre-concentration step to reject a substantial portion of silicate gangue and to partition the feed into tailings, middlings, and concentrate fractions. The middlings fraction was subsequently subjected to direct anionic flotation, enriching the iron oxide content to approximately 72.76 wt% Fe2O3 and serving as an effective bulk separation stage, removing a significant portion of the non-iron-bearing components. Reverse flotation was then conducted separately on the direct flotation concentrate and on the electrostatic separation concentrate to further improve product purity. This integrated approach produced final iron oxide concentrate of approximately 96.90 wt% Fe2O3. The final concentrate exhibits high iron oxide content with low gangue and impurity levels, demonstrating potential suitability as a feedstock for direct-reduced iron (DRI) production, subject to final industrial qualification. Overall, the results demonstrate a promising beneficiation strategy for iron ore tailings valorization while reducing reliance on primary iron ore resources.