This study is to assess the effect of magnesiumrich gangue dissolution on the ore containing chalcopyrite and carrollite from Democratic Republic of the Congo （DRC）. The ore contains 11.0 wt% magnesium and 2.4 wt% c...This study is to assess the effect of magnesiumrich gangue dissolution on the ore containing chalcopyrite and carrollite from Democratic Republic of the Congo （DRC）. The ore contains 11.0 wt% magnesium and 2.4 wt% copper. When Mg^2＋ concentration is over 20 g·L^-1 after 2 months in column bioleaching, the redox potential of leachate keeps stable, much less than that when Mg2＋ concentration is below 20 g·L^-1. Meanwhile, the extractions of Cu^2＋ and Co^2＋ from chalcopyrite with carrollite obviously inhibited by Mg^2＋ concentration of over 20 g·L^-1 were investigated. The extraction of cobalt depends on chalcopyrite dissolved in column reactor. The growth and oxidation activity of bacteria are affected by high Mg^2＋ concentration （〉20 g·L^-1） in leachate of column reactor. As the rate of gangue dissolution depends on the amount of sulfuric acid, the decrease of the particle size relates to the increase of the total particle surface area and acid consumption. Therefore, the operation of pre-leaching for magnesium removal is not the most effective and economical way to solve the problem of magnesium-rich gangue minerals dissolution.展开更多
A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a l...A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.展开更多
基金financially supported by the National High Technology Research and Development Program of China(No.2012AA061502)the National Basic Research Program of China(No.2010CB630906)
文摘This study is to assess the effect of magnesiumrich gangue dissolution on the ore containing chalcopyrite and carrollite from Democratic Republic of the Congo （DRC）. The ore contains 11.0 wt% magnesium and 2.4 wt% copper. When Mg^2＋ concentration is over 20 g·L^-1 after 2 months in column bioleaching, the redox potential of leachate keeps stable, much less than that when Mg2＋ concentration is below 20 g·L^-1. Meanwhile, the extractions of Cu^2＋ and Co^2＋ from chalcopyrite with carrollite obviously inhibited by Mg^2＋ concentration of over 20 g·L^-1 were investigated. The extraction of cobalt depends on chalcopyrite dissolved in column reactor. The growth and oxidation activity of bacteria are affected by high Mg^2＋ concentration （〉20 g·L^-1） in leachate of column reactor. As the rate of gangue dissolution depends on the amount of sulfuric acid, the decrease of the particle size relates to the increase of the total particle surface area and acid consumption. Therefore, the operation of pre-leaching for magnesium removal is not the most effective and economical way to solve the problem of magnesium-rich gangue minerals dissolution.
基金This work was supported by the Yunnan Provincial Natural Science Foundation of China （No. 2000E0101M）.
文摘A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.
