Study on Bioleaching of Yongping Low Grade Copper Sulfide Ore in Jiangxi by Mixed Cultures
|School||Central South University|
|Keywords||mixed culture moderate thermophilic bacteria bioleaching rate low-grade copper ore chalcopyrite|
Bioleaching technology has been used broadly around the world for its advantages, such as low cost, simple process and environmentally friendly. Yongping copper mine is a large skarn deposit. A large mass of copper-sulfide ore has accumulated since 1985 when the capacity reached 1000 t/d. A lot of researches have revealed that the leaching rate of copper sulfide ore was not good when using Mesophiles only. This study investigate the leaching reaction of Yongping low grade copper ore utilizing Mesophiles and Moderate thermophiles.The copper grade of Yongping copper ore is only 0.32%, and 65.63%of total copper minerals is the primary copper sulfide ore. According to the principle that ferrous oxidizing bacteria and sulfur oxidizing bacteria can cooperate in leaching reaction,4 groups of mixed bacteria were used in this study, and the leaching rate was set as criteria to screen the mixed bacteria. The leaching result showed that the combination of Ferroplasma thermophilium L1, Acidithiobacillus caldus S2 and Sulfobacillus thermosulfidooxidans YN22 under 45℃was the best group.And then, a series of orthogonal tests in shake flasks were performed to optimize the bioleaching conditions of the mixed culture Ferroplasma thermophilium L1, Acidithiobacillus caldus S2 and Sulfobacillus thermosulfidooxidans YN22. The results showed that the leaching rate of copper could reach to 94.26%were applied after 6 days, under optimized conditions of temperature 45℃、pulp density 15 w/v、rotational speed 190 r/min and initial pH 2.0. From the parameter drawn from this experiment, we can get the conclusion that the leaching mechanism is indirect interaction, and galvanic cell action was taken place between chalcopyrite and pyrite.An agitator tank was induced in this research. A 6 days’experiment was carried out, and the leaching behavior was studied. From that we can examine the practicability of battering method.