Sulphur speciation of leached chalcopyrite surfaces as determined by X-ray photoelectron spectroscopy

Klauber, C.; Parker, Andrew James; Bronswijk, Wilhelm van; Watling, H.R.

doi:10.1016/s0301-7516(00)00045-4

Cited by 209 publications

(81 citation statements)

References 28 publications

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“…This indicates that Fe(III)-S was the major Fe containing species with a component of Fe-O/OH also present [3,[26][27][28][29][30][31] (Figure 6a). The Cu 2p spectrum (Figure 6b) shows that the oxidation stat of Cu in/on chalcopyrite was +1 [32][33][34][35]. …”

Section: Xps Analysesmentioning

confidence: 99%

Chalcopyrite Dissolution at 650 mV and 750 mV in the Presence of Pyrite

Qian

et al. 2015

Metals

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Abstract:The dissolution of chalcopyrite in association with pyrite in mine waste results in the severe environmental issue of acid and metalliferous drainage (AMD). To better understand chalcopyrite dissolution, and the impact of chalcopyrite's galvanic interaction with pyrite, chalcopyrite dissolution has been examined at 75 °C, pH 1.0, in the presence of quartz (as an inert mineral) and pyrite. The presence of pyrite increased the chalcopyrite dissolution rate by more than five times at Eh of 650 mV (SHE) (Cu recovery 2.5 cf. 12% over 132 days) due to galvanic interaction between chalcopyrite and pyrite. Dissolution of Cu and Fe was stoichiometric and no pyrite dissolved. Although the chalcopyrite dissolution rate at 750 mV (SHE) was approximately four-fold greater (Cu recovery of 45% within 132 days) as compared to at 650 mV in the presence of pyrite, the galvanic interaction between chalcopyrite and pyrite was negligible. Approximately all of the sulfur from the leached chalcopyrite was converted to S 0 at 750 mV, regardless of the presence of pyrite.At this Eh approximately 60% of the sulfur associated with pyrite dissolution was oxidised to S 0 and the remaining 40% was released in soluble forms, e.g., SO42− . OPEN ACCESSMetals 2015, 5 1567

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Section: Xps Analysesmentioning

confidence: 99%

Chalcopyrite Dissolution at 650 mV and 750 mV in the Presence of Pyrite

Qian

et al. 2015

Metals

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“…Recent studies examining the microstructure of the solid sulfur phase that forms during bioleaching have focussed mostly on the dissolution of chalcopyrite (Klauber et al 2001, Parker et al 2003, Parker et al 2008, Rodriguez et al 2003. Klauber (2008) recently reviewed the surface chemistry of the oxidation of chalcopyrite and suggested the initial sulfur species formed are S-S dimers or short chain polymers followed by chain extension to form a polymeric allotrope which is finally transformed into the orthorhombic allotrope.…”

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confidence: 99%

The preferential oxidation of orthorhombic sulfur during batch culture

2009

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The formation of sulfur is predicted by the current understanding of the mechanisms involved in mineral sulfide oxidation and observed in studies of the leaching products that accumulate on the surface of the mineral. Sulfur oxidising bacteria can exploit this energy source and can remove a potentially 'rate-limiting' diffusion barrier. In this study on the activity of sulfur oxidising bacteria cultured on mixed solid sulfur allotropes, it was observed that a heterogeneous culture preferentially oxidised the orthorhombic allotrope and no significant growth on the polymeric allotrope could be demonstrated.

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“…The study by Mwase (2016) also showed that increasing the amount of cyanide concentration in the cyanide-only system had no influence on the amount of Pt leached. (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: 89%

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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Sulphur speciation of leached chalcopyrite surfaces as determined by X-ray photoelectron spectroscopy

Cited by 209 publications

References 28 publications

Chalcopyrite Dissolution at 650 mV and 750 mV in the Presence of Pyrite

Chalcopyrite Dissolution at 650 mV and 750 mV in the Presence of Pyrite

The preferential oxidation of orthorhombic sulfur during batch culture

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

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