Flotation related ESCA studies on PbS surfaces

Manocha, A. S.; Park, Robert L.

doi:10.1016/0378-5963(77)90011-3

Cited by 90 publications

(23 citation statements)

References 7 publications

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“…27,30 This oxidation is also visible in the O 1s XPS spectrum ( Figure S5 †), [31][32][33][34] and is precedented in the literature for thin PbS lms. 35 In summary, the XPS data provide evidence for a pure, stoichiometric PbS lm which becomes more stable, and therefore less prone to aerobic degradation, as it grows. The oxidized material could be PbO and/or PbSO 4 .…”

Section: Pbs Materials Characterizationmentioning

confidence: 85%

A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films

et al. 2019

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Section: Pbs Materials Characterizationmentioning

confidence: 85%

A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films

et al. 2019

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“…The sulfur spectrum of the pristine cathode consists mostly of sulfur trapped inside AC pores (S 2p 3/2 164.1 eV) 33 and some small amount of free sulfur (S 2p 3/2 164.6 eV). 34 The carbon spectrum of the pristine electrode displays peaks for C-C bonds (C 1s 284.6 eV), C-H (C 1s 285.9 eV), C=O (C 1s 288.7 eV), and C-F (C 1s 290.5 eV), coming from AC and the PVdF binder. 33,35,36 The cathodes cycled in DME Ar, DME air, and DME:DOL Ar, present rather similar XPS peaks, although with varying intensities.…”

Section: Resultsmentioning

confidence: 99%

Radical Decomposition of Ether-Based Electrolytes for Li-S Batteries

Lodovico¹,

Varzi²,

Passerini³

2017

J. Electrochem. Soc.

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In this work, the stability of ether-based electrolytes for Li-S batteries is investigated with particular regard to the effect of dissolved oxygen. Specifically, the performance of two different electrolyte solvents, i.e., 1,2-dimethoxyethane and its mixture with 1,3-dioxolane (DME:DOL, 1:1 v/v), is characterized in cells assembled in dry air environment, which would substantially lower production costs with respect to inert atmosphere (Ar). Although stability of all the components would suggest that Li-S batteries built in both the environments should behave similarly, it is found that cells containing the DME:DOL-based electrolyte are rather unstable in the presence of O 2 in contrast to those employing DME-based electrolyte, which show a relatively good performance. The different sensitivity toward O 2 of these electrolytes is associated to the ring-opening reaction of DOL, which happens to a greater extent when O 2 is present, but occurs also in its absence. Based on these results a mechanism for electrolyte degradation in Li-S cells, and its reaction with dissolved polysulfides is proposed, which rationally explain for the first time the behavior already reported in literature for these kind of batteries. These findings are also relevant to the field of Li-O 2 batteries, where these ether-based electrolytes are also used. Sulfur has been extensively investigated as a new cathode material for secondary batteries, in order to replace metal oxides normally used in lithium-ion batteries (LIBs). The first point of interest is its high theoretical specific capacity, around 1672 mAh g −1 , but, as a raw material sulfur is also non-toxic, readily available, and very inexpensive. It is indeed one of the main side products of crude oil refining, with more than 60 million tons produced annually.1 Even the relatively low operating voltage of sulfur-based cathodes, at around 2 V vs. Li/Li + , can be considered as a potential advantage, making it intrinsically safer. 2 Furthermore, the high specific gravimetric capacity of sulfur enables the remarkable specific energy of about 2600 W h kg −1 . However, Lithium-Sulfur batteries (LSB) still present some specific challenges that need to be solved to enable their commercialization.2 First, sulfur has a very low electrical conductivity, around 5 × 10 −30 S cmat 25• C, requiring the introduction of a conductive matrix, normally carbon-based. The carbon host is generally electrochemically inert, such that it decreases the energy density of the electrode as whole, especially since it is often near to 50 wt% of the total sulfur-composite mass. Secondly, and most importantly, sulfur is a conversion material undergoing several chemical transformations during discharge and forming a variety of different polysulfides with the formal oxidation state of sulfur changing from 0 to −2. Some of these intermediate species are soluble in the electrolyte, and very reactive toward both the electrolyte itself 3,4 and the lithium metal anode. 2,5 Most importantly though, their dissolution cause...

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“…The most important feature in XPS is the narrowness of the signal for lead (Pb 2p 7/2 ) at 138.1 eV, a position which was not associated with sulfides nor sulfates. According to the literature, this position can be attributed to oxides and/or thiosulfates [18,22] and evidences that new lead species are present on the surface while sulfides and sulfates are leached out. This fact is noticeable when inspecting the micrographs in Figure 2.…”

Section: Resultsmentioning

confidence: 93%

Identification of Surface Processes in Individual Minerals of a Complex Ore through the Analysis of Polished Sections Using Polarization Microscopy and X-ray Photoelectron Spectroscopy (XPS)

Silva-Quinones

Jacome-Collazos

et al. 2018

Minerals

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Understanding the changes of a mineral during ore processing is of capital importance for the development of strategies aimed at increasing the efficiency of metal extraction. This task is often difficult due to the variability of the ore in terms of composition, mineralogy and texture. In particular, surface processes such as metal re-adsorption (preg-robbing) on specific minerals are difficult to evaluate, even though they may be of importance as the re-adsorbed material can be blocking the valuable mineral and negatively affect the extraction process. Here, we show a simple yet powerful approach, through which surface processes in individual minerals are identified by combining polarization microscopy (MP) and X-ray photoelectron spectroscopy (XPS). Taking as an example a silver-containing polymetallic sulfide ore from the Peruvian central Andes (pyrite-based with small amounts of galena), we track the changes in the sample during the course of cyanidation. While polarization microscopy is instrumental for identifying mineralogical species, XPS provides evidence of the re-adsorption of lead on a pyrite surface, possibly as lead oxide/hydroxide. The surface of pyrite does not show significant changes after the leaching process according to the microscopic results, although forms of oxidized iron are detected together with the re-adsorption of lead by XPS. Galena, embedded in pyrite, dissolves during cyanide leaching, as evidenced by PM and by the decrease of XPS signals at the positions associated with sulfide and sulfate. At the same time, the rise of a lead peak at a different position confirms that the re-adsorbed lead species cannot be sulfides or sulfates. Interestingly, lead is not detected on covellite surfaces during leaching, which shows that lead re-adsorption is a process that depends on the nature of the mineral. The methodology shown here is a tool of significant importance for understanding complex surface processes affecting various minerals during metal extraction.

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Flotation related ESCA studies on PbS surfaces

Cited by 90 publications

References 7 publications

A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films

A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films

Radical Decomposition of Ether-Based Electrolytes for Li-S Batteries

Identification of Surface Processes in Individual Minerals of a Complex Ore through the Analysis of Polished Sections Using Polarization Microscopy and X-ray Photoelectron Spectroscopy (XPS)

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Flotation related ESCA studies on PbS surfaces

Cited by 90 publications

References 7 publications

A solution-based ALD route towards (CH3NH3)(PbI3) perovskite via lead sulfide films

A solution-based ALD route towards (CH3NH3)(PbI3) perovskite via lead sulfide films

Radical Decomposition of Ether-Based Electrolytes for Li-S Batteries

Identification of Surface Processes in Individual Minerals of a Complex Ore through the Analysis of Polished Sections Using Polarization Microscopy and X-ray Photoelectron Spectroscopy (XPS)

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A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films

A solution-based ALD route towards (CH₃NH₃)(PbI₃) perovskite via lead sulfide films