LEAD SORPTION ON THE SURFACE OF ZNS WITH RELEVANCE TO FLOTATION - A FLUORESCENCE REFLEXAFS STUDY

XAS was employed to determine the nature of lead speciation on the sur face of ZnS with relevance to sphalerite flotation. Lead sorbed onto t he ZnS surface from mildly acidic solutions is present in a very disor dered environment bonded to oxygen. On the addition of xanthate, bonds are formed between the surface lead and the xanthate sulfur, creating a more ordered structural environment for the lead. Atomistic compute r simulations demonstrated that direct sorption of Pb onto the ZnS sur face is energetically unfavourable. Thus, XAS has provided direct stru ctural information for the processes involved in the activation of sph alerite during galena flotation. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.