Collaborative effects of Acidithiobacillus ferrooxidans and ferrous ions on the oxidation of chalcopyrite
Collaborative effects of Acidithiobacillus ferrooxidans and ferrous ions on the oxidation of chalcopyrite
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氧化亚铁硫杆菌和亚铁离子对黄铜矿氧化的协同作用
DOI：
10.1016/j.chemgeo.2018.05.032
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发表时间：
2018-08-20
期刊：
影响因子：
3.9
通讯作者：
Wang, Rucheng
中科院分区：
文献类型：
--
作者：
Liu, Huan;Lu, Xiancai;Wang, Rucheng
近几十年来，黄铜矿的细菌浸出已被成功地开发并应用于湿法炼铜。黄铜矿的分解机理对环境修复也具有重要意义，因为采矿废物和露头岩石中的金属硫化物的微生物氧化通常会造成严重的环境污染。研究了嗜酸氧化亚铁硫杆菌（A. Fe 2+离子对黄铜矿氧化的影响。结果表明，A.氧化亚铁离子和Fe ~（2+）离子协同作用可促进黄铜矿中Cu的回收。在添加Fe ~（2+）的浸出体系中，A.氧化亚铁细菌更倾向于氧化可溶性Fe ~（2+）而不是分解黄铜矿来获取能量，这在第一阶段抑制了Cu的释放，但促进了A.氧化亚铁然而，在反应18天后，所产生的Fe 3+离子大大促进了分解，并且释放出比不含Fe 2+的生物浸出体系更多的Cu，这在其余实验中保持不变。生物浸出体系中黄铜矿的氧化和铜的释放均大于化学浸出体系。X射线光电子能谱（XPS）分析表明，硫的转化途径为S2-/S-2（2-）-> Sn 2-/S-0 -> SO 32- -> SO 42-。作为主要的最终产物，黄钾铁矾覆盖黄铜矿颗粒，从而抑制进一步氧化。值得注意的是，释放的Cu 2+离子几乎没有抑制A. Fe 3+离子在细胞表面和胞外聚合物（EPS）上均有分布，这可能是细胞在高Cu 2+溶液中存活的一种潜在机制。总的来说，黄铜矿氧化的综合模型，化学氧化和微生物氧化的合作，已被提出来阐明的生物浸出机制，并给出了一个展望其湿法冶金和环境应用。
In recent decades, the bioleaching of chalcopyrite has been successfully developed and employed in copper hydrometallurgy. Understanding the decomposition mechanism of chalcopyrite is also of great significance for environmental remediation because the microbial oxidation of metal sulfides in mining waste and outcrop rocks commonly causes serious environmental contamination. This study investigates the influence of Acidithiobacillus ferrooxidans (A. ferrooxidans) and added Fe2+ ions on the oxidation of chalcopyrite. The results show that A. ferrooxidans and added Fe2+ ions can collaboratively promote the recovery of Cu from chalcopyrite. In the bioleaching system with added Fe2+ ions, A. ferrooxidans prefer to oxidize soluble Fe2+ ions rather than decompose chalcopyrite to acquire energy, which inhibits the release of Cu at the first stage but enhances the growth of A. ferrooxidans. After reacting for 18 days, however, the produced Fe3+ ions greatly promote decomposition and release more Cu than the bioleaching system free of Fe2+, which remained in the rest experiments. Both the oxidation of chalcopyrite and the release of Cu in the bioleaching system are greater than what occurs in the chemical leaching system. Chalcocite, covellite, bornite, and elemental sulfur were identified as intermediate products, and a sulfur transforming route of S2-/S-2(2-) -> Sn2-/S-0 -> SO32- -> SO42- can be recognized by X-ray photoelectron spectroscopy. As the principle end product, jarosite covered the chalcopyrite grains and consequently inhibited further oxidation. It is noteworthy that the released Cu2+ ions barely suppressed the growth of A. ferrooxidans because they tended to be enriched only in extracellular polymeric substance (EPS), while Fe3+ ions could be found on both the cell surfaces and the EPS, which implies a potential mechanism for the survival of cells in a high Cu2+ solution. Collectively, an integrated model of chalcopyrite oxidation, collaborated by both chemical and microbial oxidation, has been proposed to elucidate the bioleaching mechanisms and to give a perspective on its hydrometallurgical and environmental applications.