To investigate the effect of three typical impurities (iron, copper and cadmium) on the flotation behavior of sphalerite, we have synthesized impurity-doped ZnS using a coprecipitation method. In the absence of CuSO4, the flotation tests show that Cd and Cu impurities greatly improve the recovery of ZnS, while Fe impurities apparently decrease the floatability of ZnS. The spectral results show that both dixanthogen and the metal xanthate are observed on Cu- and Cd-doped ZnS surfaces, but only metal xanthate is observed on Fe-doped ZnS surface. Xanthate adsorption tests show that Cd and Cu impurities favor xanthate adsorption, while Fe impurities decrease the adsorption of xanthate. In the presence of CuSO4, Cd impurities not only greatly improve the recovery of ZnS but also enhance the adsorption of xanthate. Cu impurities can improve the flotation of ZnS but show little influence on xanthate adsorption. Fe impurities apparently decrease both ZnS flotation and xanthate adsorption. (C) 2012 Elsevier Ltd. All rights reserved.