Simulating the main stages of chalcopyrite leaching and bioleaching in ferrous ions solution: An electrochemical impedance study with a modified carbon paste electrode

Author(s)

Arena, Fabiana A. ^[1] ; Suegama, Patricia H. ^[2] ; Bevilaqua, Denise ^[1] ; dos Santos, Ana L. A. ^[1] ; Fugivara, Cecilio S. ^[1] ; Benedetti, Assis V. ^[1]

Affiliation

^[1] UNESP, Inst Chem, Dept Phys Chem, Rua Francisco Degni 55, BR-14800060 Araraquara, SP - Brazil

^[2] Fed Univ Grande Dourados, Fac Exact Sci & Technol, Rodovia Dourados Itahum, Km 12, BR-79804970 Dourados, MS - Brazil

• Document type: Journal article
• Source: MINERALS ENGINEERING; v. 92, p. 229-241, JUN 2016.
• Web of Science Citations: 5

Abstract

In this work, we present an electrochemical study using a carbon paste electrode modified with chalcopyrite (CuFeS2) in solution A of T\&K medium with different ferrous ion concentrations, in the absence and presence of the bacterium Acidithiobacillus ferrooxidans. The aim was to evaluate the influence of ferrous ions and bacteria on the electrochemical behavior of chalcopyrite. Electrochemical impedance spectroscopy (EIS) was used to investigate the processes occurring at the electrode/solution interface in the different systems, considering the charge transfer reactions involving chalcopyrite and ferrous ions, the presence of a multicomponent layer, and diffusion. The main changes in the chalcopyrite response occurred before 67 h or 43 h of immersion, in the absence or presence of ferrous ions, respectively, indicating that the surface oxide layer present on chalcopyrite was dissolved faster in the presence of ferrous ions. The addition of bacteria decreased the charge transfer reaction resistance, especially when ferrous ions were present. In the presence of Fe2+, sulfur and jarosite were detected in the solid residues after leaching, while only jarosite was detected in the bioleaching experiment. The results suggested that ferrous ions accelerated the dissolution of chalcopyrite, and that overlayers including biofilms did not halt chalcopyrite dissolution, indicating that there was no passivation. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 10/13089-1 - ELECTROCHEMICAL AND BIOLEACHING STUDY OF CHALCOPYRITE (CuFeS2) WITH REDOX POTENTIAL CHANGES IN THE PRESENCE OF THE BACTERIA Acidithiobacillus ferrooxidans.
• Grantee: Fabiana Antonia Arena
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 11/19868-5 - Bioleaching of chalcopyrite (CuFeS2): mechanisms and surface interactions bacteria/mineral
• Grantee: Denise Bevilaqua
• Support Opportunities: Regular Research Grants