Results of studying the adsorption process of a potential collector reagent 4-(1-naphthylazo)naftol-1 on chalcopyrite — a monomineral of sulfide copper-nickel ore — are presented. The dependence of adsorption on solution pH, as well as kinetic and thermodynamic parameters of adsorption at 296, 299, 302, 305, and 315 K were determined. The adsorption rate constants of the reagent on chalcopyrite were calculated using pseudo-first-order and pseudo-second-order kinetic models. Adsorption isotherms at all investigated temperatures were plotted using Langmuir and Freundlich equations, and the constants for each model were determined. Using Langmuir adsorption constants at different temperatures, changes in enthalpy, entropy, and Gibbs free energy were calculated. The thermal effect values indicate that the adsorption of 4-(1-naphthylazo)naftol-1 on chalcopyrite is predominantly chemisorption. Positive enthalpy and negative Gibbs free energy values suggest that the adsorption process is endothermic and spontaneous. Contact angles on the chalcopyrite surface before and after treatment with 4-(1-naphthylazo)naftol-1 solution were measured, showing that the reagent exhibits the highest hydrophobizing ability toward chalcopyrite at pH 10.0.
V. O. Gogolishvili (Wed,) studied this question.