|FORMATION PROCESS OF BIOLOGICAL OXIDE FILM ON CHALCOPYRITE CRYSTAL SURFACE|
|Alternative Title||FORMATION PROCESS OF BIOLOGICAL OXIDE FILM ON CHALCOPYRITE CRYSTAL SURFACE
|Yang Hongying; Pan Haodan; Tong Linlin; Liu Yuanyuan
|Source Publication||ACTA METALLURGICA SINICA
|Abstract||Chalcopyrite (CuFeS2) is the most common copper bearing sulfide in the natural world, and it is also the most widespread copper ore in the world. Pyrometallurgy is used to extract copper from chalcopyrite as main industrial method. However, environmentally friendly metallurgy is advocated because of increasingly serious environmental pollution. The bacterial metallurgy is considered a new clean smelting technology to deal with low-grade and complicated composition metal resources because of short flow, simple operation, low investment and friendly environment. In the process of bioleaching, the formation of oxide film on the chalcopyrite crystal surface hindered the rapid dissolution of chalcopyrite and restricted the large-scale application of copper bioleaching. It is concluded that the oxide film inhibits material exchange between chalcopyrite and leaching liquid on the surface of the chalcopyrite and depresses its leaching rate significantly. In the paper, the advanced surface analysis technologies, such as SEM, XRD and X-ray photoelectron spectroscopy (XPS) are used to observe and analysis the surface layer in the bacterial leaching process. It is studied for the formation of bio-oxide film on the natural chalcopyrite crystal surface, in order to reveal the passivation mechanism of chalcopyrite bioleaching. Through the observation of the microcosmic morphology characteristic changes of chalcopyrite during bioleaching, different chemical composition analysis of surface oxide layer in the different bacterial oxide phase were studied. The results show that the insoluble oxide film inhibits material exchange between chalcopyrite and leaching liquid on the surface of the chalcopyrite and depresses its leaching rate significantly. The results show that the rudiments of oxide film are formed on the surface on chalcopyrite after leaching for 72 h. The oxide layer with certain thickness is formed after 96 h, and the passivation is produced. The compact film is formed after 168 h because bacterial corrosion spots and rillsare formed on the surface of chalcopyrite, and it is begun to produce serious passivation. The variation of chemical state of sulfur element is S2- -> S-0 -> S4+ -> S6+. The reaction product, including iron deficiency copper sulfide Cu1-xFe1-ySz(x < y), elemental sulfur crystal (S-0), iron oxide (Fe(III)-oxide), iron hydroxide oxide (Fe(III)-O-OH) and jarosite (KFe3(SO4)(2)(OH)(6)) are formed on the surface of chalcopyrite in order in the bioleaching process. The chalcopyrite passive film formed is caused by the stable and compact layer whose main composition is jarosite, and it produces strong passivation effects on the chalcopyrite bacterial leaching.|
|Funding Project||[National Natural Science Foundation of China]
; [High Technology Research and Development Program of China]
; [Fundamental Research Funds for the Central Universities]
Yang Hongying,Pan Haodan,Tong Linlin,et al. FORMATION PROCESS OF BIOLOGICAL OXIDE FILM ON CHALCOPYRITE CRYSTAL SURFACE[J]. ACTA METALLURGICA SINICA,2012,48(9):1145-1152.
Yang Hongying,Pan Haodan,Tong Linlin,&Liu Yuanyuan.(2012).FORMATION PROCESS OF BIOLOGICAL OXIDE FILM ON CHALCOPYRITE CRYSTAL SURFACE.ACTA METALLURGICA SINICA,48(9),1145-1152.
Yang Hongying,et al."FORMATION PROCESS OF BIOLOGICAL OXIDE FILM ON CHALCOPYRITE CRYSTAL SURFACE".ACTA METALLURGICA SINICA 48.9(2012):1145-1152.
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