Comparative study on the passivation layers of copper sulphide minerals during bioleaching

Kai-bin Fu 1,2),Hai Lin 1),Xiao-lan Mo 1),Han Wang 1),Hong-wei Wen 1),and Zi-long Wen 1) 1) School of Civil and Environmental Engineering,University of Science and Technology Beijing,Beijing 100083,China 2) Key Laboratory of Solid Waste Treatment and Resource Recycle(Ministry of Education),Southwest University of Science and Technology,Mianyang 621010,China

摘 要：The bioleaching of copper sulphide minerals was investigated by using A.ferrooxidans ATF6.The result shows the preferential order of the minerals bioleaching as djurleite>bornite>pyritic chalcopyrite>covellite>porphyry chalcopyrite.The residues were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）.It is indicated that jarosite may not be responsible for hindered dissolution.The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked.The compact surface layer of porphyry chalcopyrite may strongly hinder copper extraction.X-ray photoelectron spectroscopy（XPS） further confirms that the passivation layers of covellite,pyritic chalcopyrite,and porphyry chalcopyrite are copper-depleted sulphide Cu 4 S 11,S8,and copper-rich iron-deficient polysulphide Cu 4 Fe 2 S 9,respectively.The ability of these passivation layers was found as Cu 4 Fe 2 S 9 >Cu 4 S 11 >S 8 >jarosite.

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