Abstract
The effects of chloride ions on chalcopyrite leaching by biologically-produced ferric sulfate solution and on the iron-oxidizing culture were determined. Chloride ions significantly increased chalcopyrite leaching by ferric sulfate at 67°C and 87°C, but slowed down the leaching at 50°C. At 90°C, chloride at 5gdm-3 (0.25 g Cl- g-1 concentrate) increased the copper yield from 60 to 100% in approximately 2 weeks. Further increase in Cl- concentration did not affect the leaching. Addition of chloride increased both leaching yields and iron precipitation, which shows that the passivation was not due to iron precipitation. A decreased Ag-potential of 60 mV against an Ag/AgCl reference electrode in the presence of Cl- indicates the accumulation of partially oxidized forms of dissolved sulfur compounds such as thiosulfate and polythionate instead of elemental sulfur and, thus, a decrease in sulfur passivation. A chloride concentration of 5 g dm-3 did not affect the iron oxidation rate of the iron-oxidizing culture dominated by Leptospirillum ferriphilum.
Original language | English |
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Pages (from-to) | 830-834 |
Number of pages | 5 |
Journal | Journal of Chemical Technology and Biotechnology |
Volume | 79 |
Issue number | 8 |
DOIs | |
Publication status | Published - 1 Aug 2004 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Chalcopyrite
- Chloride
- Chloride tolerance
- Ferric leaching
- Leptospirillum ferriphilum