A novel method to limit the detrimental effect of serpentine on the flotation of pentlandite is described in this paper. Flotation results show that the presence of hydrophilic serpentine slimes results in lower recoveries of the valuable pentlandite while quartz particles do not interfere with the flotation of pentlandite. The addition of quartz particles can limit the detrimental effect of serpentine on the flotation of pentlandite. Zeta potential measurements illustrate that quartz is more negative than pentlandite and the attraction force between serpentine and quartz is stronger than that value between serpentine and pentlandite, thus serpentine slimes adsorb selectively on quartz surface in preference to the surfaces of pentlandite. (C) 2012 Elsevier B.V. All rights reserved.