Xanthate ions sorption on copper ore (chalcopyrite) is studied as a function of temperature (273-293 K) in the pH range (8-11). The sorption of xanthate ions at all the pH values is observed to increase with the increase in temperature. The changes in pH, dissolution studies of the ore, SO42- concentration determinations, and FTIR studies were employed to probe the mechanism of the process of adsorption. The results are found to fit successfully to the linear form of the Freundlich equation. The isosteric heats of adsorption (DeltaH(i)) are also calculated and show that the adsorption of xanthate on copper ore under the given experimental condition is endothermic in nature. The values of DeltaH(i) found are in conformity with the ion exchange sorption of xanthate by the chalcopyrite. (C) 2004 Elsevier Inc. All rights reserved.