A case of ferrous sulfate addition enhancing chalcopyrite leaching

Hiroyoshi, Naoki; Hirota, M.; Hirajima, Tsuyoshi; Tsunekawa, Masami

doi:10.1016/s0304-386x(97)00032-7

Cited by 105 publications

(45 citation statements)

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“…The final copper recoveries were 21.9%, 39.6%, 44.6% and 46.2% for control test, ferric added medium, ferrous added medium and the medium with the initial redox potential of 420 mV, respectively. This result is in agreement with those obtained by Hiroyoshi et al [2] and Third et al [6] who reported that ferrous iron is more effective than ferric iron to dissolve chalcopyrite. Higher copper extraction rate in the first day of ferric added medium was related to the higher efficiency of chalcocite and covellite in ferric media.…”

Section: Effect Of Ferric and Ferrous Iron On Chemical Leachingsupporting

confidence: 83%

“…Third et al [6] also studied the effect of ferrous and ferric iron on the chemical and bacterial leaching of chalcopyrite at 37˚C and found that high ferric concentration inhibits the bioleaching of chalcopyrite. They also confirmed the results obtained by Hiroyoshi et al [2] and found that chemical leaching of chalcopyrite was increased 4-fold in the presence of 0.1 M ferrous iron compared with 0.1 M ferric iron. Cordoba et al [8] studied the influence of ferric iron on chalcopyrite dissolution at low and high solution potentials and found that although ferric iron was responsible for the oxidation of chalcopyrite, ferrous iron had an important role in controlling the precipitation and nucleation of jarosite (Equation (2)).…”

Section: Introductionsupporting

confidence: 81%

“…The first model expressed that ferrous iron acts as a catalyst for converting chalcopyrite to chalcocite as a more soluble mineral (Hiroyoshi et al, [2]) and the second one related that the dissolved oxygen converted ferrous to ferric iron at the chalcopyrite surface and the reaction proceeds as expected [19].…”

Section: Effect Of Ferric and Ferrous Iron On Bacterial Leachingmentioning

confidence: 99%

“…It increases by the activity of iron-oxidizing microorganisms. This increase is beneficial for the dissolution of most of the metallic sulfides such as chalcocite, covellite and pyrite, but, in the case of chalcopyrite, the leaching behavior is more complicated in which its dissolution rate is maximal at low redox potentials [2][3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

Ahmadi¹

2012

IJNM

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The effects of ferrous and ferric iron as well as redox potential on copper and iron extraction from the copper flotation concentrate of Sarcheshmeh, Kerman, Iran, were evaluated using shake flask leaching examinations. Experiments were carried out in the presence and absence of a mixed culture of moderately thermophile microorganisms at 50˚C. Chemical leaching experiments were performed in the absence and presence of 0.15 M iron (ferric added medium, ferrous added medium and a mixture medium regulated at 420 mV, Pt. vs. Ag/AgCl). In addition, bioleaching experiments were carried out in the presence and absence of 0.1 M iron (ferric and ferrous added mediua) at pulp density 10% (w/v), inoculated bacteria 20% (v/v), initial pH 1.6, nutrient medium Norris and yeast extract addition 0.02% (w/w). Abiotic leaching tests showed that the addition of iron at low solution redox potentials significantly increased the rate and extent of copper dissolution but when ferric iron was added, despite a higher initial rate of copper dissolution, leaching process stopped. Addition of both ferrous and ferric iron to the bioleaching medium levelled off the copper extraction and had an inhibitory effect which decreased the final redox potential. The monitoring of ferrous iron, ferric iron and copper extraction in leach solutions gave helpful results to understand the behaviour of iron cations during chemical and bacterial leaching processes.

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Section: Effect Of Ferric and Ferrous Iron On Chemical Leachingsupporting

confidence: 83%

Section: Introductionsupporting

confidence: 81%

Section: Effect Of Ferric and Ferrous Iron On Bacterial Leachingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

Ahmadi¹

2012

IJNM

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“…Four candidates are most often proposed: metal deficient sulphides, elemental sulphur, polysulphides and jarosites (Cordoba et al, 2008a;Klauber, 2008;Rodriguez et al, 2003). From a process point of view, many authors agree on the fact that the dissolution rate of chalcopyrite is higher at redox potential of leach solution below a critical value (Hiroyoshi et al 1997(Hiroyoshi et al , 2000(Hiroyoshi et al , 2001. Tshilombo et al (2002) demonstrate that passivation of chalcopyrite occurs at low temperature within the potential range 450 -600 mV (vs. Ag/AgCl); Pinches et al (2000) advise potential between 380 mV and 480 mV and Cordoba et al (2008b) indicate a critical redox potential value of 413 mV above which chalcopyrite dissolution slows down.…”

Section: Discussionmentioning

confidence: 99%

Bioleaching of an organic-rich polymetallic concentrate using stirred-tank technology

et al. 2009

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The bioleaching of a concentrate produced from a black shale ore in an industrial operation in Poland was assessed. Following preliminary batch culture tests, processing in continuous conditions was tested to determine the main specifications for the application of the stirred-tank technology to this organic-rich polymetallic concentrate.The experimental work was carried out in a laboratory-scale unit consisting of 3 stirred tanks (50L or 20L) using an acidophilic and moderate thermophilic bacterial population (42°C). Different configurations of the unit and key operating parameters were tested (nutrient medium composition, solids concentration, agitation and aeration rates). The analysis of both bacterial community structure and mineralogical characteristics of the concentrate and the bioleach residues were implemented in order to better understand the chemical and biochemical reactions occurring in the system. Using the data produced during the continuous operation, downstream processing assessment for both copper and silver recovery was also carried out. 1The best copper recovery obtained in the continuous operation was 92% and a hot brine leaching of the bioleach residue (PLINT process) allowed to recover 92% of the silver.Copper and silver recoveries seemed to be limited by incomplete chalcopyrite dissolution. A preliminary techno-economic evaluation of the concentrate bioprocessing including bioleaching, copper and silver recoveries demonstrated the potential economic feasibility. Recovery of silver plays an important role in the economy of the process. This study presents promising values to further investigate the bioprocessing option.

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Inhibitory effect of iron-oxidizing bacteria on ferrous-promoted chalcopyrite leaching

Hiroyoshi

Hirota

Hirajima

et al. 1999

Biotechnol. Bioeng.

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It is generally accepted that iron‐oxidizing bacteria, Thiobacillus ferrooxidans, enhance chalcopyrite leaching. However, this article details a case of the bacteria suppressing chalcopyrite leaching. Bacterial leaching experiments were performed with sulfuric acid solutions containing 0 or 0.04 mol/dm3 ferrous sulfate. Without ferrous sulfate, the bacteria enhance copper extraction and oxidation of ferrous ions released from chalcopyrite. However, the bacteria suppressed chalcopyrite leaching when ferrous sulfate was added. This is mainly due to the bacterial consumption of ferrous ions which act as a promoter for chalcopyrite oxidation with dissolved oxygen. Coprecipitation of copper ions with jarosite formed by the bacterial ferrous oxidation also causes the bacterial suppression of copper extraction. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 478–483, 1999.

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A case of ferrous sulfate addition enhancing chalcopyrite leaching

Cited by 105 publications

References 3 publications

Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

Bioleaching of an organic-rich polymetallic concentrate using stirred-tank technology

Inhibitory effect of iron-oxidizing bacteria on ferrous-promoted chalcopyrite leaching

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