A green red mud utilization process for Fe, Al, and Si extraction and NaA–zeolite synthesis for wastewater treatment

• Multi-step process for efficient Fe, Al, and Si recovery from red mud. • Al and Si used to synthesize NaA zeolite with a maximum Ni 2+ capacity of 91.49 mg·g −1 . • Ni 2+ adsorption driven by ion exchange and interaction with hydroxyl groups. • A waste–to–waste approach that simultaneously addresses red mud and wastewater. Red mud, a hazardous byproduct of aluminum production, poses significant environmental challenges due to its large–scale generation and complex composition. Traditional disposal methods are inefficient, leading to land degradation and water pollution. The recovery of Fe, Si and Al from red mud and the preparation of zeolite materials provide a new research idea for resource utilization of red mud. This study proposed a multi–step extraction method utilizing acid leaching followed by alkali fusion for the sequential recovery of Fe, Al, and Si from red mud. Under the optimal conditions, the acid leaching process achieved recoveries of 91.2 % for Fe and 89.5 % for Al, while Si recovery reached 82.7 % through alkali fusion and water leaching. Additionally, the recovered Al and Si were employed to synthesize RML–NaA zeolite, which exhibited a maximum adsorption capacity of 91.49 mg·g −1 for Ni 2+ , showcasing its potential in treating Ni-containing wastewater. The adsorption mechanism was primarily driven by ion exchange, with additional contributions from complexation of hydroxyl and Ni 2+ . This research provides a sustainable approach to red mud management by not only recovering valuable resources but also converting industrial waste into high–value materials, contributing to both environmental protection and resource efficiency.