Abstract: The monomineral flotation test which for investigate the flotability of smithsonite and the influence of n-octanol on the flotability of smithsonite have been conducted using dodecylamine(DDA)as collector while sodium sulfide existed.The results showed that the activation of sodium sulfide to the smithsonite due to the HS- ion adsorbed on the smithsonite's surface and lead to the zeta potential drop.Smithsonite activated by sodium sulfide can be collected well by DDA while the pH of pulp located in 9.5 to 11.5.Though smithsonite activated by sodium sulfide can't be collected by n-octanol，the collected ability of DDA to smithsonite active by sodium sulfide can be enhanced obviously by n-octanol.The same flotation effect was achieved when using the combination collector which 40% mole proportion of DDA was replaced by n-octanol，compare with using DDA alone did.FTIR result showed that it is the physisorption of the interaction among sodium sulfide，DDA and n-octanol with smithsonite's surface.

Key words: Smithsonite, Sodium sulfide, Dodecylamine, N-octanol