| Abstract Scope |
This study presents an approach for the simultaneous recovery of metals from bauxite residue (BR) at relatively lower temperatures using H2 reduction to achieve near-zero waste. The proposed method involves blending BR with NaOH and subjecting it to H2 reduction, resulting in an intermediate material enriched in magnetite and water-soluble aluminate using different process parameters. Optimal process parameters were determined (temperature of 600 °C, a reduction time of 120 min, and 20 wt% NaOH addition and a reduction atmosphere of 5 vol% H2 + 95 vol %N2 with 20 L/h flowrate), resulting in recoveries: Fe (74.7%, grade = 40%), Al (81.5%), and Na (91.4%). This innovative approach represents a step towards the sustainable valorization of BR, contributing to a zero-waste economy and the efficient recovery of metals (Fe, Al, and Na) along with enriched non-magnetic fraction (Ca, Si, Ti, REEs) for further REEs, Ti recovery and additive for building materials. |