Improvement in atmospheric leaching of chalcopyrite concentrate using a new environmentally-friendly ionic liquid

Abstract

Leaching of chalcopyrite has been a great concern due to its complexity and low dissolution efficiency in acidic media. Ionic liquids have been recently proposed as an alternative to common leaching agents. In this study, a novel aliphatic ionic liquid (IL) was synthesized for the dissolution of chalcopyrite which is not only eco-friendly than previously reported ionic liquids but also more efficient. 1,2-Ethane diammonium hydrogen sulfate [EDA][HSO4] was synthesized and characterized by several techniques such as 1H NMR, 13C NMR and FT-IR analyses. In addition, response surface methodology (RSM) was applied for studying the effect of various parameters such as ionic liquid and oxidant concentrations, temperature, time and pulp density on the chalcopyrite leaching by [EDA][HSO4], and a model was developed for predicting copper extraction in the studied range. The results showed that the effect of temperature on the process became more noticeable at a higher oxidant concentration. Therefore, by using H2O2 25% (w/w) at the temperature of 55 °C, the leaching efficiency achieved was over 91%. The mineralogical analysis of the leach residue also confirmed that the dissolution of chalcopyrite was remarkable.