The anodic behaviour of covellite in chloride solutions

Nicol, M.J.; Basson, Petrus

doi:10.1016/j.hydromet.2017.06.018

Cited by 18 publications

(16 citation statements)

References 18 publications

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“…Figures 3 and 4 show that time, chloride and H2SO4 concentration, as well as the interaction of time-H2SO4 and Cl-H2SO4 affected Cu extraction. In Figure 3, the linear effects demonstrate what has been said by several authors [13,20,37], with respect to the effect of the concentration of chloride present in the leaching media and the effect of sulfuric acid concentration. The concentration of chloride has a great impact on the dissolution of copper from a sulfide; such as chalcocite.…”

Section: Anovasupporting

confidence: 76%

Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Toro

Briceño

Pérez

et al. 2019

Metals

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Chalcocite is the most important and abundant secondary copper ore in the world with a rapid dissolution of copper in an acid-chloride environment. In this investigation, the methodology of surface optimization will be applied to evaluate the effect of three independent variables (time, concentration of sulfuric acid and chloride concentration) in the leaching of pure chalcocite to extract the copper with the objective of obtaining a quadratic model that allows us to predict the extraction of copper. The kinetics of copper dissolution in regard to the function of temperature is also analyzed. An ANOVA indicates that the linear variables with the greatest influence are time and the chloride concentration. Also, the concentration of chloride-time exerts a significant synergic effect in the quadratic model. The ANOVA indicates that the quadratic model is representative and the R2 value of 0.92 is valid. The highest copper extraction (67.75%) was obtained at 48 h leaching under conditions of 2 mol/L H2SO4 and 100 g/L chloride. The XRD analysis shows the formation of a stable and non-polluting residue; such as elemental sulfur (S0). This residue was obtained in a leaching time of 4 h at room temperature under conditions of 0.5 mol/L H2SO4 and 50 g/L Cl−.

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Section: Anovasupporting

confidence: 76%

Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Toro

Briceño

Pérez

et al. 2019

Metals

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“…In the range of 20 to 50 (g/L), chloride has no positive effects based on the leaching time, obtaining maximum copper extractions of 44.9% and 56.3%, respectively. This agrees with the results of other research [24], which indicates that CuS oxidation to CuS 2 is possible with any chloride concentration, but the oxidation of CuS 2 is only possible with very high potential or high chloride concentrations [25].…”

Section: Anovasupporting

confidence: 92%

“…Research studies on covellite leaching have been varied, evaluating alternatives that contemplate different dissolution media, such as ammonia [16,20], nitrates [21,22], and chlorides [4,[23][24][25]. Bioleaching has also been considered, including bacteria such as thiobacillus ferrooxidans, acidithiobacillus ferrooxidans, and acidithiobacillus thiooxidans, which can grow under anaerobic conditions where ferric ions are used as electron receptors [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

“…Otherwise, the stage expressed in Equation (5), which corresponds to the transformation of covelline to dissolved copper, is slower and requires an activation energy close to 72 kJ/mol, suggesting electrochemical control [24,33]. Nicol and Basson [25] indicated that the oxidation of covellite occurs as an intermediate stage in which it is transformed into polysulfide CuS 2 :…”

Section: Introductionmentioning

confidence: 99%

“…Covellite can be oxidized over a wide range of chloride concentrations and electrochemical potential; however, the subsequent oxidation of CuS 2 is only achieved from media with high chloride concentrations or high potentials [25]. Copper leaching processes in a chloride media are especially adequate for leaching non-ferrous minerals such as chalcocite, djurleite, digenite, and covellite, since in these cases, the leaching solutions contain low levels of dissolved iron [3].…”

Section: Introductionmentioning

confidence: 99%

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Statistical Study for Leaching of Covellite in a Chloride Media

Pérez

Toro

Saldaña

et al. 2020

Metals

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Covellite is a secondary copper sulfide, and it is not abundant. There are few investigations on this mineral in spite of it being formed during the leaching of chalcocite or digenite; the other investigations on covellite are with the use of mineraloids, copper concentrates, and synthetic covellite. The present investigation applied the surface optimization methodology using a central composite face design to evaluate the effect of leaching time, chloride concentration, and sulfuric acid concentration on the level of copper extraction from covellite (84.3% of purity). Copper is dissolved from a sample of pure covellite without the application of temperature or pressure; the importance of its purity is that the behavior of the parameters is analyzed, isolating the impurities that affect leaching. The chloride came from NaCl, and it was effectuated in a size range from –150 to +106 μm. An ANOVA indicated that the leaching time and chloride concentration have the most significant influence, while the copper extraction was independent of sulfuric acid concentration. The experimental data were described by a highly representative quadratic model obtained by linear regression (R2 = 0.99).

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