Effects of microorganisms on surface properties of chalcopyrite and bioleaching

Abstract:To better understand chalcopyrite leach mechanisms and kinetics, for improved Cu extraction during hydrometallurgical processing, chalcopyrite leaching has been conducted at solution redox potential 750 mV, 35-75˝C, and pH 1.0 with and without aqueous iron addition, and pH 1.5 and 2.0 without aqueous iron addition. The activation energy (E a ) values derived indicate chalcopyrite dissolution is initially surface chemical reaction controlled, which is associated with the activities of Fe 3+ and H + with reaction orders of 0.12 and´0.28, respectively. A surface diffusion controlled mechanism is proposed for the later leaching stage with correspondingly low E a values. Surface analyses indicate surface products (predominantly S n 2´a nd S 0 ) did not inhibit chalcopyrite dissolution, consistent with the increased surface area normalised leach rate during the later stage. The addition of aqueous iron plays an important role in accelerating Cu leaching rates, especially at lower temperature, primarily by reducing the length of time of the initial surface chemical reaction controlled stage.

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“…Many investigators [4,[84][85][86] have pointed out that Equation (10) is also relevant to both acid mine drainage and heap leaching:…”

Section: Identification Of Reactions and Mechanismsmentioning

confidence: 99%

Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Wei

Qian

et al. 2016

Minerals

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“…Due to the presence of surface functional groups, such as carboxyl (-COOH), amino (-NH 2 ), and hydroxyl (eOH), the microorganisms have surface charges, which play a critical role in the interaction between microorganisms and their environments (Lytle et al, 2002;Chen et al, 2008). Both bacteria, A. thiooxidans and A. ferrooxidans, showed a point of zero charge (PZC) of 3.0 and 2.1, respectively (Fig.…”

Section: Bacteria Mobility In Electric Fieldmentioning

confidence: 99%

“…Bioleaching has been developed to recover valuable metals from ores and rocks. Recently, it has been considered as a highly promising method for the treatment of metal contaminated soil (Chen et al, 2008). The most widely used bacteria in bioleaching are Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans, which are capable of oxidizing the reduced sulfur and ferrous ions, creating acidic conditions favorable for metal removal from soil (Naresh Kumar and Nagendran, 2009).…”

Section: Introductionmentioning

confidence: 99%

Comparative study of simultaneous removal of As, Cu, and Pb using different combinations of electrokinetics with bioleaching by Acidithiobacillus ferrooxidans

Kim

Lee

et al. 2012

Water Research

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“…Zeta potential is a parameter widely used to characterize the charge of mineral and microbial surfaces (Chen et al, 2008;Devasia et al, 1993;Liu et al, 2006;Solari et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…It has been demonstrated that A. ferrooxidans without EPS presents less attachment to minerals than the bacteria with EPS (Yu et al, 2011;Harneit et al, 2006;Chandraprabha and Natarajan, 2013). Bacteria present charge due to functional groups such as amino (NH 2 ), carboxyl (COOH), and hydroxyl (OH), which are constituents of lipids, sugars and proteins on their EPS (Sharma et al, 2003;Chen et al, 2008;Devasia et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Study of the Adhesion Mechanism of Acidithiobacillus ferrooxidans to Pyrite in Fresh and Saline Water

Robbiano¹

2019

Preprint

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In the present work electrostatic forces are evaluated as the cause of attachment of Acidithiobacillus ferrooxidans to pyrite. Streaming potential of A. ferrooxidans and pyrite was measured in two environment, fresh water and saline water (water with 35 g/L of NaCl) at different pH's values. At the same time, attachment kinetics of A. ferrooxidans to pyrite were carried out in fresh and saline water at pH 4. The results showed that A. ferrooxidans and pyrite present lower streaming potential (comparing absolute values) in saline water than in fresh water, indicating the compression in the electric double layer caused by Cl- and Na+ ions. Simultaneously, it was determined that the bacteria present a higher attachment to pyrite in fresh water than in saline water. This suggests that electrostatics forces do not play a leading role in the adhesion mechanism.

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Effects of microorganisms on surface properties of chalcopyrite and bioleaching

Cited by 41 publications

References 16 publications

Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Comparative study of simultaneous removal of As, Cu, and Pb using different combinations of electrokinetics with bioleaching by Acidithiobacillus ferrooxidans

Study of the Adhesion Mechanism of Acidithiobacillus ferrooxidans to Pyrite in Fresh and Saline Water

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