Abstract:Red mud has been widely studied as an adsorbent for wastewater treatment due to its containing active components in recent years. The residues, obtained from red mud after recovering aluminum, sodium and iron by reductive sintering-leaching-magnetic separation, still contain a certain amount of active components. Defluorination performance of residue for synthetic wastewater bearing 25 mg/L fluoride was investigated. Defluorination efficiency is 72.19% under the optimum conditions including initial pH value of 5, residue dosage of 15 g/L, temperature of 40 ℃, and adsorbing time of 30 min.