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Mathematical modeling of thermophilic bioleaching of chalcopyrite / Javier Vilcáez in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 951–960 Titre : Mathematical modeling of thermophilic bioleaching of chalcopyrite Type de document : texte imprimé Auteurs : Javier Vilcáez, Auteur ; Chihiro Inoue, Auteur Année de publication : 2009 Article en page(s) : pp. 951–960 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Sulphide  ores  Bioleaching  Reaction  kinetics  Modelling Résumé : Previous studies have shown that the different preferences of thermophiles to oxidize S0 or Fe2+ is reflected by different [Fe3+]/[Fe2+] levels in solution. In those studies it was concluded that [Fe3+]/[Fe2+] governs the thermophilic bioleaching of chalcopyrite rather than temperature or pH. Therefore, the proposed model is mainly based on the finding that thermophilic bioleaching of chalcopyrite is governed by [Fe3+]/[Fe2+] that result from the activity of thermophiles. A direct interaction between chalcopyrite and thermophiles is neglected because it has been reported that this is not a general behavior for all thermophiles. The case of constant temperature, initial pH 1.5–2.5, and chalcopyrite concentrates is considered. The main assumption is that chalcopyrite can be anodically oxidized or cathodically reduced depending on [Fe3+]/[Fe2+] in solution. When chalcopyrite is oxidized at high [Fe3+]/[Fe2+] levels, Cu2+ is formed directly at low rates: CuFeS2 + 4Fe3+ → Cu2+ + 5Fe2+ + S0. Whereas, when chalcopyrite is reduced at low [Fe3+]/[Fe2+] levels, an intermediate (Cu2S) is formed at higher rates: CuFeS2 + Fe2+ + Cu2+ + 2H+ → Cu2S + 2Fe3+ + H2S. Because the oxidation of Cu2S is relatively fast: Cu2S + 4Fe3+ → 2Cu2+ + S0 + 4Fe2+, its accumulation is assumed to be negligible. To take into account the possibility of chalcopyrite being oxidized or reduced depending on [Fe3+]/[Fe2+] in solution, the principle of mixed potentials is used. The model is validated by comparing the calculated and measured values of copper extraction, total iron in solution, and pH. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900079X [article] Mathematical modeling of thermophilic bioleaching of chalcopyrite [texte imprimé] / Javier Vilcáez, Auteur ; Chihiro Inoue, Auteur . - 2009 . - pp. 951–960. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 951–960 Mots-clés : Sulphide  ores  Bioleaching  Reaction  kinetics  Modelling Résumé : Previous studies have shown that the different preferences of thermophiles to oxidize S0 or Fe2+ is reflected by different [Fe3+]/[Fe2+] levels in solution. In those studies it was concluded that [Fe3+]/[Fe2+] governs the thermophilic bioleaching of chalcopyrite rather than temperature or pH. Therefore, the proposed model is mainly based on the finding that thermophilic bioleaching of chalcopyrite is governed by [Fe3+]/[Fe2+] that result from the activity of thermophiles. A direct interaction between chalcopyrite and thermophiles is neglected because it has been reported that this is not a general behavior for all thermophiles. The case of constant temperature, initial pH 1.5–2.5, and chalcopyrite concentrates is considered. The main assumption is that chalcopyrite can be anodically oxidized or cathodically reduced depending on [Fe3+]/[Fe2+] in solution. When chalcopyrite is oxidized at high [Fe3+]/[Fe2+] levels, Cu2+ is formed directly at low rates: CuFeS2 + 4Fe3+ → Cu2+ + 5Fe2+ + S0. Whereas, when chalcopyrite is reduced at low [Fe3+]/[Fe2+] levels, an intermediate (Cu2S) is formed at higher rates: CuFeS2 + Fe2+ + Cu2+ + 2H+ → Cu2S + 2Fe3+ + H2S. Because the oxidation of Cu2S is relatively fast: Cu2S + 4Fe3+ → 2Cu2+ + S0 + 4Fe2+, its accumulation is assumed to be negligible. To take into account the possibility of chalcopyrite being oxidized or reduced depending on [Fe3+]/[Fe2+] in solution, the principle of mixed potentials is used. The model is validated by comparing the calculated and measured values of copper extraction, total iron in solution, and pH. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900079X