An integrated process for iron recovery and binder production from bauxite residue (red mud)

Bauxite residue, the waste product from the Bayer process, typically consists of approximately 40 wt% Fe2O3, which makes it a potential resource for Fe. This study presents an integrated process in which Fe is extracted in a first stage, followed by valorisation of the remaining residue towards alkali-activated binders. About 75 wt% of residue was melted with the addition of C, B2O3 and SiO2 at 1250 degrees C. During this treatment, and after water- quenching, a significant amount of Fe was formed as well as an almost fully vitrified slag. The slag was used to produce inorganic polymers with satisfactory compressive strengths. However, tincalconite, a boron salt eventually precipitated, demonstrating limited incorporation of B in the binder. (C) 2019 Elsevier B.V. All rights reserved.