Study on the Settling of Aluminum Tailings Mud Improved by Metal Ions

Aluminum tailings mud, which is a harmful residue, is a type of waste formed by bauxite washing during the process of alumina production. In this work, the effects of the pH of slurries and the common associated metal ions K+ and Fe3+ on the sedimentation characteristics of slurries were studied. The effects of common metal ions in tailings slurries on the sedimentation characteristics of slurries were studied via a zeta potential analyzer, X-ray diffraction analysis, and an electron scanning microscope. The results show that, compared with that of K+, the sedimentation effect of the tailings slurry is greater after the addition of Fe3+. Analysis of the mechanism revealed that within a certain pH range, the addition of metal ions can compress the thickness of the electric double layer on the surface of tailings mud, and high-valence ions (Fe3+) result in more electric double-layer compression than monovalent ions (K+), which is more conducive to the agglomeration of tailings mud particles. This study elucidates the regulatory mechanisms governing interfacial interactions between metal ions and aluminum tailings particles, providing a scientific basis for optimizing high-efficiency dewatering processes in aluminum industry tailings. The findings hold significant implications for mitigating environmental pressures in tailings storage facilities, advancing resource utilization of solid wastes, and promoting green production practices. The conclusions have certain guiding significance for the efficient drainage of aluminum tailings mud.