Cryogenic XPS study of fast-frozen sulfide minerals: Flotation-related adsorption of n-butyl xanthate and beyond
2016 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 206, 65-73 p.Article in journal (Refereed) PublishedText
Cryogenic XPS of wet particulate samples separated via centrifugation and fast-frozen allows quasi in situ examination of solid surfaces, adsorbates, and reaction products, largely preventing the loss both of volatiles and hydrated species at mineral/water interfaces. Here, the cryo-XPS has been applied to characterize the surfaces and interfacial layers of natural pyrite (FeS2), chalcopyrite (CuFeS2), and galena (PbS) in solutions of a common flotation collector, potassium n-butyl xanthate (KBX), in conjunction with zeta-potential measurement. It was found, in particular, that dibutyl dixanthogen was the major adsorbate at pyrite in 0.1 mM KBX and 10 mM KBX solutions; dixanthogen and cuprous xanthate in the next stage were formed on chalcopyrite, and predominant chemisorbed butyl xanthate was present at galena, including in 10 mM KBX solution. The results may suggest that the production of dixanthogens at the interface has been underestimated while the quantities of surface metal xanthates could be over evaluated in previous studies. Pronounced differential charging effects were observed in the XPS experiment for the samples moderately hydrophobized by the xanthate treatment; we proposed that the effect was due to electrically isolated mineral particles with hydrophobic and ice-repellent surfaces, which retained, however, some frozen water islets.
Place, publisher, year, edition, pages
2016. Vol. 206, 65-73 p.
Cryogenic XPS, Minerals, Xanthate, Adsorption, Hydrophobicity
IdentifiersURN: urn:nbn:se:umu:diva-114675DOI: 10.1016/j.elspec.2015.12.003ISI: 000369210900009OAI: oai:DiVA.org:umu-114675DiVA: diva2:897463