Kinetic Modelling and Equilibrium of Amphoteric Collector Adsorption on Silica and Hematite

Abstract

Abstract Most of the world iron ores are associated with siliceous impurities. Upgrading schemes depend mostly on the removal of these impurities by flotation and/or selective flocculation techniques, which mainly influenced by the adsorption of collectors on both valuable and gangue minerals. In this study, the adsorption of amphoteric collector (dodecyl-N-carboxyethyl-N-hydroxyethyl-imidazoline) on silica and hematite was studied. The collector adsorption exhibits the preferential adsorption on silica at acidic pH range. While in case of hematite, the adsorption was the same over entire the studied pH range. The temperature was kept constant at 298 K and contact time of 60 min was found, from kinetic study, to be adequate to achieve equilibrium. In addition, two simplified kinetic models including a pseudo first-order equation and pseudo second-order equation were used to determine kinetic parameters, rate constants, and equilibrium sorption capacities. It was shown that the pseudo first-order equation perfectly describes the adsorption of collector. Moreover, the analysis of experimental isotherm data using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations showed that the Freundlich model reasonably fits the experimental data in the studied concentration range.