中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 16 No. 5 October 2006 |
CANG Da-qiang(蒼大強)1,2, WANG Dian-zuo(王淀佐)3
（1. School of Metallurgy and Ecology Engineering,
University of Science and Technology Beijing, Beijing 100083, China;
2. Key Laboratory of Ecological and Recycling Metallurgy, Ministry of Education, Beijing 100083, China;
3. School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract: The chalcopyrite anode dissolution behavior in the presence or absence of bacteria in 9 K media using bacteria modified powder microelectrode at 30 ℃ was studied. It is found that during the anode dissolution, many intermediate transient reactions occur accompanying with the production of chalcocite and covellite at potential between −0.075 V and −0.025 V (vs SCE). At low scanning potential between −0.1 and −0.250 V, the iron ion is released in ferrous form, but at the relative high potential up to 0.7 V, it is the ferric one. The presence of Thiobacillus ferrooxidans makes peak current increase and the initial peak potential negatively move, hinting the decomposed oxidation reaction easily occurred and especially the iron ion released and ferrous oxidation reaction enhanced. The characteristic at potential between −0.75 and −0.5 V demonstrates the Thiobacillus ferrooxidans also contributes to the element sulfur formed on the oxidation surface and removed during anode process. The added ferric in the cell could enhance the dissolution reaction, while the increased acid under pH=2 might slightly hamper the process. The anode dissolution kinetics studies show that the presence of bacteria could decease corrosion potential from 0.238 V to 0.184 V and increase the corrosion current density from 1.632 14×10−8 A/cm2 to 2.374 11×10−7A/cm2.
Key words: biohydrometallurgy; bioleaching; anode oxidation; bacteria modification; powder microelectrode; chalcopyrite; kinetics
