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Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite / Agnieszka Mierczynska-Vasilev in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 985–993 Titre : Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite : Correlation between coverage, wettability, and flotation Type de document : texte imprimé Auteurs : Agnieszka Mierczynska-Vasilev, Auteur ; David A. Beattie, Auteur Année de publication : 2011 Article en page(s) : pp. 985–993 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Flotation  depressants  Sulfide  ores  Surface  modification Résumé : A carefully chosen selection of CMC polymers was used to probe the depression of talc and chalcopyrite and to highlight the effect of specific alterations of the bulk polymer chemistry on the power and selectivity of the depressants. In situ tapping mode atomic force microscopy (AFM), captive bubble contact angle measurements, and flotation tests were used to study the adsorption of the CMC polymers on chalcopyrite and talc. The degree of substitution and distribution of substitution of carboxymethyl groups on CMC was seen to have a strong influence on the ability of the polymers to adsorb onto the surface of talc and chalcopyrite. High substitution results in low coverage on both minerals whereas low substitution results in higher coverage. The influence of distribution of substitution (random or clustered) was also seen to affect the adsorption, with more random/even substitution giving rise to greater adsorption on talc and chalcopyrite. The contact angle of talc and chalcopyrite is significantly altered in the presence of the three polymers, with increased surface coverage (determined by AFM) correlating with the ability of the polymers to decrease the wettability of talc and chalcopyrite. This trend was also followed in single and mixed mineral talc and chalcopyrite flotation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000968 [article] Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite : Correlation between coverage, wettability, and flotation [texte imprimé] / Agnieszka Mierczynska-Vasilev, Auteur ; David A. Beattie, Auteur . - 2011 . - pp. 985–993. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 985–993 Mots-clés : Flotation  depressants  Sulfide  ores  Surface  modification Résumé : A carefully chosen selection of CMC polymers was used to probe the depression of talc and chalcopyrite and to highlight the effect of specific alterations of the bulk polymer chemistry on the power and selectivity of the depressants. In situ tapping mode atomic force microscopy (AFM), captive bubble contact angle measurements, and flotation tests were used to study the adsorption of the CMC polymers on chalcopyrite and talc. The degree of substitution and distribution of substitution of carboxymethyl groups on CMC was seen to have a strong influence on the ability of the polymers to adsorb onto the surface of talc and chalcopyrite. High substitution results in low coverage on both minerals whereas low substitution results in higher coverage. The influence of distribution of substitution (random or clustered) was also seen to affect the adsorption, with more random/even substitution giving rise to greater adsorption on talc and chalcopyrite. The contact angle of talc and chalcopyrite is significantly altered in the presence of the three polymers, with increased surface coverage (determined by AFM) correlating with the ability of the polymers to decrease the wettability of talc and chalcopyrite. This trend was also followed in single and mixed mineral talc and chalcopyrite flotation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000968

Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite / Robert G. Acres in Minerals engineering, Vol. 23 N° 11-13 (Octobre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 928–936 Titre : Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite Type de document : texte imprimé Auteurs : Robert G. Acres, Auteur ; Sarah L. Harmer, Auteur ; David A. Beattie, Auteur Année de publication : 2011 Article en page(s) : pp. 928–936 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulfide  ores  Leaching  Oxidation Résumé : The surface species present on two pure chalcopyrite samples (one with a smooth fracture surface; one with a rough fracture surface) and one heterogeneous sample containing both chalcopyrite and pyrite have been studied using synchrotron X-ray photoelectron spectroscopy (SXPS), near-edge X-ray Absorption Fluorescence Spectroscopy (NEXAFS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements were performed for samples fractured in N2 and for samples subsequently exposed to pH 1 HCl solution for 2 h. The comparison of freshly fractured and solution exposed mineral surfaces has allowed for the investigation of the role of other mineral phases on the development of chalcopyrite surface species, and the role of chalcopyrite grain size on surface species development. Analysis of the chalcopyrite region of each sample indicates that increased surface roughness and the presence of pyrite in intimate contact with chalcopyrite increases the formation of surface sulfur species that are implicated in the formation of passivating layers on leached chalcopyrite surfaces. ToF-SIMS analysis of the chalcopyrite and pyrite regions of the heterogeneous sample support the conclusions obtained from the synchrotron surface analysis experiments. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000634 [article] Synchrotron XPS, NEXAFS, and ToF-SIMS studies of solution exposed chalcopyrite and heterogeneous chalcopyrite with pyrite [texte imprimé] / Robert G. Acres, Auteur ; Sarah L. Harmer, Auteur ; David A. Beattie, Auteur . - 2011 . - pp. 928–936. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 11-13 (Octobre 2010) . - pp. 928–936 Mots-clés : Sulfide  ores  Leaching  Oxidation Résumé : The surface species present on two pure chalcopyrite samples (one with a smooth fracture surface; one with a rough fracture surface) and one heterogeneous sample containing both chalcopyrite and pyrite have been studied using synchrotron X-ray photoelectron spectroscopy (SXPS), near-edge X-ray Absorption Fluorescence Spectroscopy (NEXAFS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The measurements were performed for samples fractured in N2 and for samples subsequently exposed to pH 1 HCl solution for 2 h. The comparison of freshly fractured and solution exposed mineral surfaces has allowed for the investigation of the role of other mineral phases on the development of chalcopyrite surface species, and the role of chalcopyrite grain size on surface species development. Analysis of the chalcopyrite region of each sample indicates that increased surface roughness and the presence of pyrite in intimate contact with chalcopyrite increases the formation of surface sulfur species that are implicated in the formation of passivating layers on leached chalcopyrite surfaces. ToF-SIMS analysis of the chalcopyrite and pyrite regions of the heterogeneous sample support the conclusions obtained from the synchrotron surface analysis experiments. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510000634