Kinetics and mechanisms of arsenic and sulfur release from crystalline orpiment

Mirazimi, Mohamad; Mohammadi, Maryam; Liu, Wenying

doi:10.1016/j.mineng.2021.107032

Cited by 4 publications

(5 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, if on the other hand, as recently suggested by Mirazimi et al, 42 there is an oxidation of sulfur to thiosulfate species taking place (i.e., a partial sulfur oxidation), we obtain as overall reaction…”

Section: ■ Discussionmentioning

confidence: 53%

“…However, if on the other hand, as recently suggested by Mirazimi et al, there is an oxidation of sulfur to thiosulfate species taking place (i.e., a partial sulfur oxidation), we obtain as overall reaction normalA normals 2 normalS 3 false( normals false) + 6 normalO 2 + 3 normalH 2 normalO + h ν → normalA normals 2 normalO 3 false( normals false) + 3 normalH 2 normalS 2 normalO 3 false( normala normalq false) In case the orpiment containing paint was not exposed to light, no arsenolite was found, while the binding medium area surrounding the orpiment showed the presence of As(V) species. In the previous research, the hypothesis was that the As(V) species evolved from the As 2 O 3 species .…”

Section: Discussionmentioning

confidence: 67%

“…In addition, outside of the As hotspot, the XANES data show that As(V) species were present. The relatively high concentration of As in the medium and the XANES of positions 2−4 suggest that some of the arsenolite had dissolved in the water-diluted egg yolk (since orpiment is less soluble in water than arsenolite, this phenomenon was not observed in the previous experiment 41,42 ).…”

Section: ■ Resultsmentioning

confidence: 81%

“…Recently, leaching tests have been performed to investigate the arsenic and sulfur species released from orpiment in aqueous solutions. , Arsenites (AsO 3 3– or polymers of this ion) were identified as the most abundant As species, while no arsenolite was identified.…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Two Pathways for the Degradation of Orpiment Pigment (As₂S₃) Found in Paintings

et al. 2023

View full text Add to dashboard Cite

Paintings are complex objects containing many different chemical compounds that can react over time. The degradation of arsenic sulfide pigments causes optical changes in paintings. The main degradation product was thought to be white arsenolite (As2O3), but previous research also showed the abundant presence of As(V) species. In this study, we investigate the influence of the presence of a medium on the degradation mechanism of orpiment (As2S3) using synchrotron radiation (SR)-based tomographic transmission X-ray microscopy, SR-based micro-X-ray fluorescence, and X-ray absorption near edge structure spectroscopy. Upon direct illumination of dry orpiment powder using UV–visible light, only the formation of As2O3 was observed. When As2S3 was surrounded by a medium and illuminated, As2O3 was only observed in the area directly exposed to light, while As(V) degradation species were found elsewhere in the medium. Without accelerated artificial light aging, As(V)(aq) species are formed and migrate throughout the medium within weeks after preparation. In both scenarios, the As(V) species form via intermediate As(III)(aq) species and the presence of a medium is necessary. As(V)(aq) species can react with available cations to form insoluble metal arsenates, which induces stress within the paint layers (leading to, e.g., cracks and delamination) or can lead to a visual change of the image of the painting.

show abstract

Section: ■ Discussionmentioning

confidence: 53%

Section: Discussionmentioning

confidence: 67%

Section: ■ Resultsmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Two Pathways for the Degradation of Orpiment Pigment (As₂S₃) Found in Paintings

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Аморфный, в большей степени, чем кристаллический, трисульфид мышьяка (As 2 S 3 ) нестабилен в щелочных и окислительных условиях. Выделение мышьяка в форме арсенита, который впоследствии окисляется до арсената, и серы в виде тиосульфата с переходом в сульфат путем окисления и диспропорционирования возрастает с повышением рН, концентрации растворенного кислорода и температуры [9].…”

Section: Introductionunclassified

The disposal of sulfide-arsenic cake

Novikov

Galkova

Maltsev

2023

Izv.VUZ. Tsvet. Met.

View full text Add to dashboard Cite

When processing sulfide copper-zinc concentrates at copper smelters, sulfide-arsenic cakes are formed, which are subject to disposal. To solve the global environmental problem of arsenic in the metallurgical and mining industries, it must be reliably concentrated and fixed in technological flows with subsequent waste disposal. The fusion of arsenic cake with elemental sulfur leads to the formation of vitreous sulfides, which are less toxic in comparison with dispersed powdered cake, homogeneous and compact in shape. The fusion product is represented by non-stoichiometric arsenic sulfide, similar in composition to As2S5. The high chemical stability of glassy arsenic sulfides is confirmed by the results of leaching by TCLP method. The fusion products have 100 times lower solubility compared to the initial cake. Achieving the solubility of arsenic in the alloy below the threshold concentration (5 mg/dm3 ) makes it possible to recommend the disposal of arsenic cake by fusing it with elemental sulfur. The fusion products belong to non-hazardous waste and are suitable for long-term storage. The composition and structure of cake fusions with iron powder have been studied. New compounds of variable composition were identified in the fused samples: arsenides and sulfides of iron, arsenic sulfides and arsenopyrites. Studies have shown that the products of fusion with iron have a solubility 10–15 times lower than the arsenic compounds in the initial cake but above the threshold concentration as per TCLP method. Therefore, fusion with iron cannot be recommended for practical use for the disposal of arsenic cakes.

show abstract