[Display omitted] • 3418A/DDTC mixture has better selectivity of jamesonite. • Mixed collector shows a shorter conditioning time than conventional DDTC. • Chemisorption is detected on the jamesonite surface treated by mixed collector. • 3418A/DDTC mixture can improve the flotation of refractory Pb-Sb-Zn ore. In this study, mixed collectors containing sodium diisobutyl dithiophosphinate (Aerophine 3418A (3418A), Solvay) and sodium diethyldithiocarbamate (DDTC) were used to improve the flotation of jamesonite, and adsorption mechanism of this system was investigated by means of flotation experiments, FTIR and SEM-EDS analyses, and DFT-D calculation. The results of micro-flotation experiments indicated that 3418A/DDTC mixture with the molar ratio of 1:2 (3418A/DDTC mixture) exhibited excellent selectivity, and presented a shorter conditioning time than conventional DDTC in the flotation of jamesonite. Batch flotation experiments confirmed that 3418A/DDTC mixture could significantly improve the flotation performance of natural refractory Pb-Sb-Zn ore. FTIR and SEM-EDS analyses showed that 3418A and DDTC could perform synergistic chemisorption on jamesonite surface, while the residual amount of 3418A on the surface of jamesonite was significantly higher than that of DDTC. Further analysis with DFT calculation showed that the 3418A could rapidly overcome the binding interactions of surrounding molecules from the micelle and then form effective adsorption in the jamesonite surface, while the DDTC could strengthen the hydrophobic layer due to the H...N hydrogen bonds. [ABSTRACT FROM AUTHOR]