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1. Alkaline pretreatment of a polymetallic sulfide (Fe-Pb-Mn) ore containing silver increases the efficiency of cyanidation by decreasing elemental sulfur content and by exposing sulfide surfaces

   https://doi.org/10.1016/j.mineng.2023.108325  

   Larrabure, Gonzalo ; Silva-Quiñones, Dhamelyz ; Teplyakov, Andrew V. ; Rodriguez-Reyes, Juan Carlos ( November 2023 , Minerals Engineering)

   Polymetallic sulfide ores are often not amenable to cyanide leaching due to the presence of several elements and minerals capable of interfering with this process. Thus, various strategies, such as chemical pretreatments, are often studied to improve the efficiency of cyanidation. Beyond the results of such strategies, it is important to understand the changes occurring on the mineral samples during these pretreatments. Herein, an alkaline pre- treatment was applied to a silver concentrate (~8 kg Ag/t) composed of polymetallic sulfides (Fe-Pb-Mn), which increased the silver extraction during subsequent cyanidation from 40% to 80% and decreased the cyanide consumption in half (from approximately 60 to 30 kg NaCN/t). X-ray diffraction (XRD) and ICP-MS indicated that the pretreatment could remove significant amounts of elemental sulfur, which is a known cyanicidal agent. The dissolution of significant amounts of sulfur was confirmed by chemical analysis, which also demonstrated that the dissolution of iron, lead, manganese, and silver were negligible during pretreatment. At surface level, X- ray photoelectron spectroscopy (XPS) demonstrated that the pretreatment exposes fresh sulfide surfaces (e. g. pyrite). In addition, the XPS spectra indicated that the pretreatment facilitated the exposure of clean mineral surfaces. The presence of cleaner surfaces suggested a more uniform and less hindered diffusion of leaching agents through the mineral. Indeed, fitting the extraction data to the shrinking core model showed that pre- treated samples featured a nearly ideal diffusion-controlled process, while in the case of untreated samples this fitting was less adequate. During cyanidation of both untreated and pretreated samples, lead build-up was detected on the surface (readsorption), which suggested that this phenomenon does not affect the efficiency of a leaching process. This study highlights the importance of combining bulk analytical methods with surface- sensitive techniques to obtain a more complete understanding of leaching processes. 

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2. Chemical dynamics study on the gas-phase reaction of the D1-silylidyne radical (SiD; X 2 Π) with deuterium sulfide (D 2 S) and hydrogen sulfide (H 2 S)

   https://doi.org/10.1039/d1cp01629f  

   Goettl, Shane J. ; Doddipatla, Srinivas ; Yang, Zhenghai ; He, Chao ; Kaiser, Ralf I. ; Silva, Mateus X. ; Galvão, Breno R. ; Millar, Tom J. ( June 2021 , Physical Chemistry Chemical Physics)

   The reactions of the D1-silylidyne radical (SiD; X 2 Π) with deuterium sulfide (D 2 S; X 1 A 1 ) and hydrogen sulfide (H 2 S; X 1 A 1 ) were conducted utilizing a crossed molecular beams machine under single collision conditions. The experimental work was carried out in conjunction with electronic structure calculations. The elementary reaction commences with a barrierless addition of the D1-silylidyne radical to one of the non-bonding electron pairs of the sulfur atom of hydrogen (deuterium) sulfide followed by possible bond rotation isomerization and multiple atomic hydrogen (deuterium) migrations. Unimolecular decomposition of the reaction intermediates lead eventually to the D1-thiosilaformyl radical (DSiS) (p1) and D2-silanethione (D 2 SiS) (p3) via molecular and atomic deuterium loss channels (SiD–D 2 S system) along with the D1-thiosilaformyl radical (DSiS) (p1) and D1-silanethione (HDSiS) (p3) through molecular and atomic hydrogen ejection (SiD–H 2 S system) via indirect scattering dynamics in barrierless and overall exoergic reactions. Our study provides a look into the complex dynamics of the silicon and sulfur chemistries involving multiple deuterium/hydrogen shifts and tight exit transition states, as well as insight into silicon- and sulfur-containing molecule formation pathways in deep space. Although neither of the non-deuterated species – the thiosilaformyl radical (HSiS) and silanethione (H 2 SiS) – have been observed in the interstellar medium (ISM) thus far, astrochemical models presented here predict relative abundances in the Orion Kleinmann-Low nebula to be sufficiently high enough for detection. 

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3. Thiol-Activated 1,2,4-Thiadiazolidin-3,5-diones Release Hydrogen Sulfide through a Carbonyl-Sulfide-Dependent Pathway

   https://doi.org/10.1021/acs.joc.2c01220  

   Smith, Haley M. ; Pluth, Michael D. ( September 2022 , The Journal of Organic Chemistry)
4. Cyclic Sulfenyl Thiocarbamates Release Carbonyl Sulfide and Hydrogen Sulfide Independently in Thiol-Promoted Pathways

   https://doi.org/10.1021/jacs.9b06319  

   Zhao, Yu ; Steiger, Andrea K. ; Pluth, Michael D. ( August 2019 , Journal of the American Chemical Society)
5. Properties of iron sulfide, hydrosulfide, and mixed sulfide/hydrosulfide cluster anions through photoelectron spectroscopy and density functional theory calculations

   https://doi.org/10.1063/1.4964651  

   Yin, Shi ; Bernstein, Elliot R. ( October 2016 , The Journal of Chemical Physics)