Ionic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies

Abstract

We are pleased to submit for publication in Physical Chemistry Chemical Physics the attached manuscript entitled " Ionic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies".In this work, we report an application of aqueous solutions of ionic liquids (ILs) based on imidazolium and ethylammonium cations, and hydrogensulfate, nitrate, acetate and dicyanamide anions in a complex study of leaching of Cu and Fe metals from naturally occurring chalcopyrite ore. This is the first study, to our knowledge, providing a systematic comparison of the leaching performance of ILs composed of different cations and anions, and without added oxidants such as ferric ions and dissolved oxygen.We characterised the liquid, solid and gas phases of the leaching systems and showed that the anion plays an important role in defining the leaching ability of ILs. Our results indicated that in neat IL aqueous solutions, without the addition of oxidants, the surface chemical reaction is the rate determining step. EDS/XPS spectroscopy was performed in combination with SEM imaging to study the evolution of the chalcopyrite surface upon leaching. Gas Chromatography coupled with Mass Spectroscopy was applied to investigate the evolution of species in the gas phase upon leaching, and novel dependencies between the evolution of gas species, formation of oxide layer and metal extraction efficiency were noticed and are summarised.Taken together, we feel that the work will have significant impact on the development of efficient solvent systems for metal extraction from copper and iron bearing ores. The obtained information on the solubility of Cu and Fe in ILs with different structures will be useful for the design of highly efficient IL solvents for chalcopyrite dissolution. The initial data obtained for solid and gas phase alterations upon leaching are essential for further investigation of the complete mechanism of chalcopyrite leaching in IL solutions. The discovered dependence between extinction coefficient of copper, ε(Cu), Page 1 of 23Physical Chemistry Chemical Physics and performance of the studied leaching systems is suggested to be used to predict extraction properties of lixiviant.Therefore this work carries not only fundamental information of the solubility of chalcopyrite in ILs, but also presents a further path to study the mechanism of this complex process. We commend this manuscript to you for publication in Physical Chemistry Chemical Physics and look forward to your response.Sincerely, Prof. Tom Welton Page 2 of 23 Physical Chemistry Chemical PhysicsIonic liquids for metal extraction from chalcopyrite: solid, liquid and gas phase studies O. Kuzmina, E. Symianakis, D. Godfrey, T. Albrecht and T. WeltonNon-oxidative leaching in ionic liquids revealed novel dependencies between the evolution of gas species, passivation layers and metal extraction efficiency. We studied leaching of Cu and Fe from naturally occurring chalcopyrite ore using aqueous solutions of ionic liquids based on imidazolium and ethylam...

Leaching Chalcopyrite with an Imidazolium-Based Ionic Liquid and Bromide

“…The Arrhenius graph (Figure 8) was obtained with the apparent kinetic constants k d . The activation energy in the studied temperature range was 75.73 kJ/mol, similar to reported values for other IL systems [32]. The obtained results corroborate the proposed model for the system under study.…”

“…The authors obtained the highest copper dissolution of 98.3% with 10% (v/v) of IL [hmim] [HSO 4 ] in an aqueous solution, with a particle size of under 45 µm, 25% hydrogen peroxide as an oxidant, a temperature of 45 • C, and a leaching time of 120 min. Kuzmina et al [32] studied chalcopyrite dissolution using the series 1-butylimidazolium hydrogen sulfate ([HC 4 ([bmim][OAc]), and found that the best IL to leach chalcopyrite was 1-butylimidazolium hydrogen sulfate, although the recovery rate was low without an oxidizing agent. Lastly, the ionic liquid [bmim][HSO 4 ] has shown the best performance in leaching mineral species, including refractory ores and precious metals [33][34][35].…”

Electrolytic production of copper from chalcopyrite

“…Al-Zubeidei et al [36] studied the leaching of chalcopyrite with several structurally simple ionic liquids, and found that the progression of leaching was similar to that of H2SO4 solutions, and that more polar cations improve extraction. Kuzmina et al [37] studied chalcopyrite leaching in a series of ionic liquids in the absence of oxidants, and the 1butylimidazolium hydrogen sulfate composition showed the best performance. Still, the leaching ability of ionic liquids alone was insufficient to extract copper from chalcopyrite.…”

Solvometallurgical process for extraction of copper from chalcopyrite and other sulfidic ore minerals

“…31 Different authors have investigated the leaching of copper from the sulfidic copper ore chalcopyrite using ionic liquids. [32][33][34][35][36] The addition of polar organic solvents such as alcohols to the aqueous acidic solutions can increase the copper extractions. [37][38][39][40] Methanesulfonic acid, an organic acid was used as an alternative for mineral acid for extraction of copper from chalcopyrite.…”