A simple but effective method for the enrichment of Al in red mud waste

Abstract

This study proposes transforming red mud, an abundant byproduct from the aluminum industry, into minerals using Na2CO3 activation for efficient water leaching. It was aimed at breaking down the rigid Al-Si network structure. The investigation compares the effects of sodium salts, with Na2CO3 achieving an 88.90 % aluminum leaching rate crucial for activating katoite and cancrinite in red mud. Using XRD, FT-IR, SEM-EDS, in situ hot-stage microscopy, FactSage, and Material Flow Analysis, the study explores changes in Na2CO3-loaded red mud, elucidating its role in converting aluminum-bearing minerals into water-soluble aluminates at a low temperature of 900 °C for an optimum activation duration of 90 min, with a preferred loading of 32 % Na2CO3. Introducing a new cyclic aluminum extraction method from red mud, utilizing sodium salts, especially Na2CO3, the study optimizes the activation process through a comprehensive exploration of thermal and mineral transformation behaviors. Quantitative analysis of Na and Al elements ensures successful recovery and cyclic utilization of Na2CO3, maintaining aluminum extraction efficiency above 82 % after six cycles. This economically feasible closed-loop system aligns with principles of industrial efficiency and climate change mitigation. Na2CO3, acting as an activator and a carbon sink, showcases significant potential for sustainable aluminum production.