Recovery of iron and aluminum from iron-rich bauxite residue by an integrated phase reconstruction approach

Abstract

The comprehensive recovery of iron and aluminum from iron-rich bauxite residue (IRBR) is of critical importance both in terms of resource utilization and environment protection, which, however, is challenging due to the intertwined phases between Iron and aluminum. In this study, an integrated phase reconstruction approach, consisting of alkali roasting, two-stage column leaching, and carbonation decomposition, was proposed for Fe/Al recovery from IRBR. The results demonstrated that aluminum and sodium were fused into soluble substances such as sodium aluminate (Na7Al3O8, NaAlO2, and Na2O (Al2O3)11) in the alkali roasting process, allowing for the separation of Al and Fe in the subsequent leaching process. Following water/FeCl3 solution leaching, the removal efficiency of aluminum reached 84.66%, and Fe content in the residue could be enriched to 55.56%. Fe can be recycled as iron concentrate, and Al in the leaching solution with 75.95 g/L can be recovered in the form of Al(OH)3 through carbonation decomposition. This work provides an alternative strategy for the recovery of resources from IRBR, with potential implications for the sustainable development of the aluminum industry.