A thermodynamic approach to ion flotation. II. Metal ion selectivity in the SDS-Cu-Ca and SDS-Cu-Pb systems

Two thermodynamically based, theoretical models are developed to predict th e selectivity coefficients for Ca2+/ CU2+ and Pb2+/Cu2+ in ion flotation wi th sodium dodecylsulfate (SDS) as the collector. Pseudo selectivity coeffic ients predicted from surface tension measurements are 1.12 and 1.69 for Ca2 + /Cu2+ and Pb2+/Cu2+. This agrees rather poorly with experimentally measur ed selectivity coefficients of 1.44 and 2.14, but does predict the order of selectivity Cu2+ < Ca2+ < Pb2+. The selectivity coefficients estimated by the dehydration model are 1.55 and 2.07 for Ca2+/Cu2+ and Pb2+/Cu2+ respect ively, which agrees well with the experimentally measured values. (C) 2001 Elsevier Science B.V. All rights reserved.