Probing the interfacial role of hydrolysed polymaleic anhydride for efficient target adsorption in scheelite–calcite flotation system: Experimental application and atomic-scale mechanisms

• HPMA selectively depresses calcite recovery from 91.64% to 18.61% at pH 7 and 10 mg·L−1 dosage, while preserving scheelite floatability. • FTIR and XPS confirm preferential chemisorption of HPMA carboxyl groups at calcite Ca sites, effectively blocking NaOL adsorption. • DFT simulations show HPMA binds far more strongly to calcite (104) (−1166.441 kJ·mol−1) than to scheelite (112) (335.180 kJ·mol−1), driving selective separation. • Mulliken population analysis reveals polar covalent Ca–O bonds at the calcite–HPMA interface, enabling targeted passivation and differential surface reactivity for efficient scheelite recovery.