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

Arena, Fabiana Antonia; Suegama, P. H.; Bevilaqua, Denise; Santos, Ana Laura; Fugivara, Cecilio Sadao; Benedetti, Assis Vicente

doi:10.1016/j.mineng.2016.03.025

Cited by 25 publications

(10 citation statements)

References 40 publications

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“…Despite the difference in ferrous ions concentration added to the flasks (0.100, 0.200 and 0.300 mol L -1 ), the final copper recovery rate obtained was almost the same value. This result was confirmed by EIS measurements for shorter immersion times in other studies 17,18 , where the chalcopyrite surface seems to be partially blocked indicated by an increase of real impedance in the presence of At. ferrooxidans.…”

Section: Leaching Experimentssupporting

confidence: 83%

“…Low copper recovery can be associated to the high initial ferrous ions concentration readily available in solution, since bacteria prefer to oxidize soluble ferrous ions than chalcopyrite as energy source, as described by Gómez et al 19 . Oxidizing chalcopyrite rather than soluble ferrous iron may favor biofilm formation that could hinder further chalcopyrite dissolution as described elsewhere 17,18 .…”

Section: Leaching Experimentsmentioning

confidence: 99%

“…Therefore, in an optimized system, it is necessary not only low redox potential values (400-450 mV) but also presence of ferrous ions to ensure higher rates of copper recovery. Recently, it was demonstrated by electrochemical impedance spectroscopy that ferrous ions activated chalcopyrite surface even in the presence of surface precipitates and the redox potential range could help the maintenance of this activation 18 . Thus, we propose a new approach to interpret the effect of ferrous ions and redox potential on chalcopyrite dissolution considering the combined effect of these parameters, since both parameters cannot be interpreted separately (Figure 8).…”

Section: Leaching Experimentsmentioning

confidence: 99%

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Effect of redox potential on chalcopyrite dissolution imposed by addition of ferrous ions

et al. 2017

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ABSTRACT:Copper is one of the metals with great economic interest and about 70% of it is found in nature as chalcopyrite mineral (CuFeS 2 ). Due to its slow dissolution kinetics, chalcopyrite dissolution is still a challenge for industries and researchers. Control of redox potential though has been said to be the key for increasing dissolution rate in chalcopyrite leaching systems. The current work investigated the effect of redox potential by ferrous ions addition on chalcopyrite (bio)leaching experiments. In abiotic systems, 90% of copper was leached into solution when redox potential was kept low (around 420 mV/Ag/AgCl) whereas in bacterial systems (610 mV/Ag/AgCl) low copper dissolution was observed. SEM analysis suggested presence of new phases that were confirmed by XRD to be elemental sulfur and jarosites and a significant decrease of chalcopyrite peak heights in these analyses was also observed. Jarosite was the only new phase detected in bacterial systems. Passivation of chalcopyrite surface did not occur in either conditions. The results clearly show that low redox potential along with presence of ferrous ions has positively influenced copper recovery, confirming the existence of a critical redox potential range where chalcopyrite dissolution is favored.

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Section: Leaching Experimentssupporting

confidence: 83%

Section: Leaching Experimentsmentioning

confidence: 99%

Section: Leaching Experimentsmentioning

confidence: 99%

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Effect of redox potential on chalcopyrite dissolution imposed by addition of ferrous ions

et al. 2017

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“…(Sasaki et al, 2010;Parker et al, 2003;Klauber et al, 2001;Yuzer et al, 2000;Hackl et al, 1995;Mycroft et al, 1995;Pratt et al, 1994). There are some studies (Arena et al, 2016;Olvera et al, 2015;Yang et al, 2015;Khoshkhoo et al, 2014;Hackl et al, 1995) that have used electrochemistry and XPS to explain specifically the phenomenon of passivation in chalcopyrite leaching, although it is acknowledged that chalcopyrite passivation it is not a similar system to the one explored in this study.…”

Section: Introductionmentioning

confidence: 88%

Characterizing the leaching of sperrylite (PtAs 2 ) in cyanide-based solutions

Mwase

Petersen

2017

Hydrometallurgy

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The mineral sperrylite (PtAs2), unlike other Pt minerals, has shown to be resistant to cyanide leaching, even at elevated temperatures of 50°C. This has prevented further development of a two-stage heap leaching process, of which the second stage is cyanide leaching for a Platreef ore, due to a considerable portion of the Pt being present as sperrylite.Through a comprehensive set of leaching tests, this study has shown that sperrylite leaches slowly in cyanide due to eventual passivation. The addition of ferricyanide to the cyanide solution results in significantly more Pt being leached (up to 16 times) than with cyanide only under identical process conditions. However, over time passivation occurred in this system also, but can be seemingly be overcome by filtering, rinsing and re-suspending the sperrylite. This was further investigated using a reactor system continuously fed with a ferricyanide-cyanide to leach a fixed bed of sperrylite mineral. Again, gradual passivation of the mineral phase was observed, which was fully reversible following a day of feeding with distilled water. XPS analysis of fresh and leached mineral indicated a depletion of As on the mineral surface, which tallied with an observed preferential leaching of As during leaching, at least initially. As a result, it is postulated that a less cyanide-soluble compound of the form PtAs(X) forms, where x is less than 2. The ease with which the leaching process can be restarted after rinsing the mineral indicates that the adsorption of solution species is the key step in forming a passivating layer. This adsorption is potentially favoured by the gradual surface transformation.Finally, an electrochemical study confirmed that the ferricyanide-cyanide system facilitated an electron transfer reaction at the sperrylite surface with the likely oxidation of As and reduction of the ferricyanide. Gradual passivation of the surface was also observed in this system.

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“…Therefore, electrochemical methods have been commonly applied to investigate the dissolution processes of sulfide minerals. Arena et al (2016) used electrochemical impedance spectroscopy (EIS) to study chalcopyrite leaching, and found that the addition of bacteria reduced the charge transfer reaction resistance. Zhao et al (2015) compared the cyclic voltammograms (CV) of chalcopyrite and bornite electrodes.…”

Section: Introductionmentioning

confidence: 99%

Bioleaching and Electrochemical Behavior of Chalcopyrite by a Mixed Culture at Low Temperature

et al. 2021

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Low-temperature biohydrometallurgy is implicated in metal recovery in alpine mining areas, but bioleaching using microbial consortia at temperatures <10°C was scarcely discussed. To this end, a mixed culture was used for chalcopyrite bioleaching at 6°C. The mixed culture resulted in a higher copper leaching rate than the pure culture of Acidithiobacillus ferrivorans strain YL15. High-throughput sequencing technology showed that Acidithiobacillus spp. and Sulfobacillus spp. were the mixed culture’s major lineages. Cyclic voltammograms, potentiodynamic polarization and electrochemical impedance spectroscopy unveiled that the mixed culture enhanced the dissolution reactions, decreased the corrosion potential and increased the corrosion current, and lowered the charge transfer resistance and passivation layer impedance of the chalcopyrite electrode compared with the pure culture. This study revealed the mechanisms via which the mixed culture promoted the chalcopyrite bioleaching.

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

Cited by 25 publications

References 40 publications

Effect of redox potential on chalcopyrite dissolution imposed by addition of ferrous ions

Effect of redox potential on chalcopyrite dissolution imposed by addition of ferrous ions

Characterizing the leaching of sperrylite (PtAs 2 ) in cyanide-based solutions

Bioleaching and Electrochemical Behavior of Chalcopyrite by a Mixed Culture at Low Temperature

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