کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10279854 | 465447 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
XPS characterisation of chalcopyrite chemically and bio-leached at high and low redox potential
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: XPS characterisation of chalcopyrite chemically and bio-leached at high and low redox potential XPS characterisation of chalcopyrite chemically and bio-leached at high and low redox potential](/preview/png/10279854.png)
چکیده انگلیسی
Leaching of chalcopyrite in sulphuric acid media has been investigated under constant redox potential conditions in solution. The leaching residues were analysed by X-ray diffraction and X-ray photoelectron spectroscopy. The leaching was performed at two different levels of redox potential, 420 mV and 600 mV (Pt vs. Ag, AgCl), at 65 °C. Both bioleaching and chemical leaching were investigated. The bioleaching was continuous, with a culture of the extremely thermophilic microorganism Sulfolobus metallicus. The high redox potential experiment was a “normal” bioleaching experiment; i.e., normal air flow, etc., the redox potential obtained at steady state was 600 mV and the low redox condition was achieved by a reduced airflow and additions of a sodium sulphite solution. The chemical leaching was done as a redox titration with potassium permanganate as oxidising agent to maintain the redox potential at 600 mV and 420 mV, respectively. Chalcopyrite leaching was greatly enhanced at the lower redox potential for both types of leaching, but especially during chemical leaching, which also resulted in large amounts of elemental sulphur. Passivation of the leaching at high redox potential was followed by a concomitant precipitation of large amounts of jarosite. Bioleaching resulted in a more complete sulphur oxidation to sulphate, even at low redox potential. It is thus concluded that passivation during chalcopyrite leaching is caused by jarosite and not elemental sulphur.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Minerals Engineering - Volume 18, Issue 5, April 2005, Pages 505-515
Journal: Minerals Engineering - Volume 18, Issue 5, April 2005, Pages 505-515
نویسندگان
Ã
ke Sandström, Andrei Shchukarev, Jan Paul,