Xin Baoping, Zhang Di, Zhang Xian, Xia Yunting, Wu Feng, Chen Shi, Li Li
The Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081, PR China.
Bioresour Technol. 2009 Dec;100(24):6163-9. doi: 10.1016/j.biortech.2009.06.086. Epub 2009 Aug 4.
The bioleaching mechanism of Co and Li from spent lithium-ion batteries by mixed culture of sulfur-oxidizing and iron-oxidizing bacteria was investigated. It was found that the highest release of Li occurred at the lowest pH of 1.54 with elemental sulfur as an energy source, the lowest occurred at the highest pH of 1.69 with FeS(2). In contrast, the highest release of Co occurred at higher pH and varied ORP with S + FeS(2), the lowest occurred at almost unchanged ORP with S. It is suggested that acid dissolution is the main mechanism for Li bioleaching independent of energy matters types, however, apart from acid dissolution, Fe(2+) catalyzed reduction takes part in the bioleaching process as well. Co(2+) was released by acid dissolution after insoluble Co(3+) was reduced into soluble Co(2+) by Fe(2+) in both FeS(2) and FeS(2) + S systems. The proposed bioleaching mechanism mentioned above was confirmed by the further results obtained from the experiments of bioprocess-stimulated chemical leaching and from the changes in structure and component of bioleaching residues characterized by XPS, SEM and EDX.
研究了硫氧化菌和铁氧化菌混合培养从废旧锂离子电池中生物浸出钴和锂的机制。结果发现，以元素硫为能源时，锂的最高释放量出现在最低pH值1.54时，以FeS₂为能源时，锂的最低释放量出现在最高pH值1.69时。相反，钴的最高释放量出现在较高pH值且S + FeS₂的氧化还原电位（ORP）变化时，钴的最低释放量出现在以S为能源时ORP几乎不变的情况下。研究表明，酸溶解是锂生物浸出的主要机制，与能源物质类型无关，然而，除了酸溶解外，Fe²⁺催化还原也参与了生物浸出过程。在FeS₂和FeS₂ + S体系中，不溶性Co³⁺被Fe²⁺还原为可溶性Co²⁺后，Co²⁺通过酸溶解释放出来。上述提出的生物浸出机制通过生物过程刺激化学浸出实验以及以X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和能谱仪（EDX）表征的生物浸出残渣的结构和成分变化所获得的进一步结果得到了证实。
