Citric acid as a green rejuvenator: mechanistic insights into the complete recovery of floatability for oxidized arsenopyrite

The rehabilitation of oxidized arsenopyrite surfaces is critical for sustainable mineral processing. This study demonstrates that citric acid (CA) effectively restores arsenopyrite floatability by multi-mechanistic surface regeneration. XPS depth-profiling and TOF-SIMS results indicated that CA selectively chelation dissolved Fe 3+ -bearing oxides while competitively displacing re-adsorbed arsenate. This molecular selectivity reduced arsenic leaching by 55 % compared to H 2 SO 4 , owing to targeted complexation rather than indiscriminate proton attack. The results of electrochemical analysis, AFM and EDS analysis confirmed electrochemical reactivation initiating at surface asperities to enhance charge transfer and homogenization. HRTEM/SAED revealed nanostructure reconfiguration from epitaxial strained interfaces to functional polycrystalline domains enriched with FeS/As 2 S 3 nanocrystals, facilitating S 2 2− exposure. Consequently, CA achieved significant flotation recovery improvement while maintaining >80 % efficacy over 4–5 reuse cycles, pioneering a sustainable pathway for polymetallic sulfide ore rehabilitation. • Citric acid dissolved Fe 3+ -oxides via chelation, exposing the hydrophobic lattice. • Competitive arsenate displacement reduced As leaching by 55 % than H 2 SO 4 . • Surface homogenization enhanced charge transfer and xanthate reduction. • Nano-reconstitution formed polycrystalline domains, restoring hydrophobicity.