The dissolution of chalcopyrite in chloride solutions

Velásquez-Yévenes, Lilian; Nicol, M.J.; Miki, Hajime

doi:10.1016/j.hydromet.2010.03.001

Cited by 84 publications

(54 citation statements)

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“…This value is similar to that obtained by Cheng and Lawson (1991a) and Dutrizac et al (1974a). It is also similar to the value of 73 kJ mol -1 for the dissolution of chalcopyrite obtained by Velásquez-Yévenes (2009, 2010b under similar conditions. This high value of the activation energy suggests that the rate of covellite dissolution is limited by the rate of chemical and/or electrochemical reactions on surface of the covellite.…”

Section: Effect Of Temperaturesupporting

confidence: 90%

“…The effect of dissolved oxygen on the rate of covellite leaching was investigated because the rate of dissolution of chalcopyrite was found to be enhanced in the presence of dissolved oxygen (Velásquez-Yévenes et al, 2009, 2010a. Leaching experiments were carried out, with or without dissolved oxygen, at the same potential (600 mV).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…In dilute chloride solutions at ambient temperatures, results were obtained that have shown that the rate of leaching of chalcopyrite under these conditions is enhanced if the solution potential is controlled within a potential window (550-620 mV) (Velásquez-Yévenes et al, 2009, 2010aNicol et al, 2010). In the proposed mechanism for enhanced leaching at low potentials, it was suggested that a covellitelike phase is produced as an intermediate and a future publication will present electrochemical evidence for such an intermediate.…”

Section: Introductionmentioning

confidence: 99%

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The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

2011

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. (2011) The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures. Hydrometallurgy, This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTThe kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures. AbstractAn experimental study of the comparative kinetics of dissolution of various synthetic copper sulphides (covellite, chalcocite, digenite) in dilute chloride solutions has been carried out at ambient temperatures such as could be encountered in the heap leaching of secondary copper sulphide minerals.The dissolution of sized synthetic covellite particles was carried out in dilute HCl solutions containing known concentrations of copper(II) and iron(III) at controlled potentials. The results show that the rate of dissolution is similar at potentials of 600 and 650 mV, but is predictably less at a potential of 550 mV. The rate of dissolution is remarkably similar to that of chalcopyrite under similar conditions and is largely independent of Cl -and HCl concentration in the range 0.2 to 2.5 M and 0.1 to 1 M respectively. The effect of temperature is significant and an activation energy of 71.5 kJ mol -1 was derived which confirms a chemical or electrochemical rate-determining reaction on the mineral surface. A mineralogical study of the residue after leachingshows that most of the sulphur is associated with unreacted covellite and occurs as isolated globules on the surface with over 90% of the unreacted covellite surface free of sulphur.Dissolution of synthetic chalcocite and digenite is rapid compared with that of covellite under the same conditions. At a potential of 500 mV, the relatively rapid A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTinitial dissolution of chalcocite and digenite does not proceed beyond about 50% and 45% copper dissolution, respectively, as predicted from the thermodynamics. These results confirm the formation of a covellite-like phase as an intermediate which cannot be leached at a potential of 500 mV. An increase in the potential results in rapid dissolution of this "secondary covellite", relative to primary covellite. These results provide useful information for the conditions that should be used for the heap leaching of ores containing secondary copper sulphide minerals.

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Section: Effect Of Temperaturesupporting

confidence: 90%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

2011

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“…Many researchers have argued that chloride ions are beneficial to leaching in the hydrometallurgical processing of chalcopyrite [1][2][3][4][5][6][7], owing to the formation of soluble copper chloro complexes [8,9]. Cupric and ferric ions have been tested as oxidants in chloride media [10][11][12][13] with beneficial results.…”

Section: Introductionmentioning

confidence: 99%

“…Habashi [23] proposed the use of nitric acid (HNO 3 ) and indicated that in sulfide ore leaching nitrate ions act as an oxidant by forming NO or NO 2 gases and oxygen, from the decomposition of HNO 3 . Other researchers [24,25] related the better performance of HNO 3 as an oxidant due to its high redox potential. In a system of CuFeS 2 , HNO 3 and H 2 SO 4 , the reaction products are Cu 2+ , Fe 3+ , S 0 and NO gas.…”

Section: Introductionmentioning

confidence: 99%

Leaching of Chalcopyrite in Acidified Nitrate Using Seawater-Based Media

et al. 2018

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Abstract:The leaching of copper from industrial copper ore with 4.8 wt % chalcopyrite by acidified nitrate with seawater based media was investigated. Water quality (pure water and seawater), temperature (25-70 • C), reagent concentration, and nitrate type (sodium and potassium) were studied variables. Leaching conditions were: 100 g ore/1 L solution; P 80 of 62.5 µm; 400 rpm and leaching time, varying between 3 and 7 days. Nitrates in sulfuric acid are known to be good oxidants for sulfide ores. This study showed that up to 80 wt % copper could be extracted at 45 • C in 7 days. In the absence of nitrate, under the same leaching conditions, only a 28 wt % copper extraction was achievable. The extraction rate increased to 97.2 wt % when leach temperature was increased to 70 • C in nitrate-chloride-acid media. The presence of chloride ions also increased the copper extraction rate. The copper extraction achieved in seawater systems were higher than in water systems under the same leaching conditions (increased by an average of 18 wt %). This effect can be attributable to the contribution of chloride that increases proton (H + ) activity.

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Long‐term outcome for men with teratoma found at postchemotherapy retroperitoneal lymph node dissection

Svatek

Spiess

Sundi

et al. 2009

Cancer

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BACKGROUND:Patients with pure teratoma within the postchemotherapy retroperitoneal lymph node dissection (PC‐RPLND) specimen traditionally have been considered at low risk for disease progression. The objectives of this study were to determine the disease‐related outcomes of patients who had pure teratoma identified at the time of PC‐RPLND and to examine the prognostic value of clinical variables that were identified previously as important predictors of disease recurrence in these patients.METHODS:Between 1980 and 2003, 97 patients with metastatic nonseminomatous germ cell tumor and pure teratoma histology at the time of PC‐RPLND were identified. The medical records of these patients were reviewed retrospectively for pertinent clinical and treatment‐related outcomes.RESULTS:At a median follow‐up of 7.4 years, 21 patients (22%) developed recurrent disease after PC‐RPLND. The 5‐year and 10‐year probabilities (±standard error) of freedom from disease recurrence were 81% ± 4% and 76% ± 5%, respectively. The postchemotherapy α‐fetoprotein (AFP) level and mediastinal involvement at presentation were statistically significant predictors of disease recurrence on multivariate analysis. Nine of 97 patients (9.3%) died from testis cancer, and 4 patients died from other causes.CONCLUSIONS:In patients with pure teratoma histology at PC‐RPLND, mediastinal involvement at presentation and the presence of an elevated AFP level before PC‐RPLND predicted an unfavorable outcome. The absence of mediastinal involvement and normal AFP level, however, did not confirm freedom from disease recurrence. Patients who had teratoma at the time of PC‐RPLND remained at considerable risk for disease progression because of the unpredictable nature of teratoma and the presence of unrecognized, active germ cell disease outside the retroperitoneum. Cancer 2009. © 2009 American Cancer Society.

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The dissolution of chalcopyrite in chloride solutions

Cited by 84 publications

References 14 publications

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

Leaching of Chalcopyrite in Acidified Nitrate Using Seawater-Based Media

Long‐term outcome for men with teratoma found at postchemotherapy retroperitoneal lymph node dissection

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