【作者】 张耀；

【导师】 杨洪英；

【作者基本信息】 东北大学 ， 生物化工， 2008， 硕士

【摘要】 生物冶金技术具有充分利用资源、成本低、投资少和基本无环境污染等优点。在国内外已经被广泛研究并应用于工业实践。本研究以四种硫化矿单矿物—黄铁矿、黄铜矿、磁黄铁矿、镍黄铁矿为研究对象,对硫化矿进行细菌浸出试验研究,运用碳糊电极对硫化矿细菌浸出过程的电化学机理进行了较为系统的研究。试验所用浸矿细菌HQ0211,是以氧化亚铁硫杆菌为主的混合菌。通过电镜观察可知,处于对数期的细菌菌体饱满,个体体积一致,形态比较均匀。处于稳定期的菌体弯曲,长短不一。处于衰亡期的细菌出现了多种形态,甚至畸形,有的菌体开始自溶。针对单矿物黄铁矿、黄铜矿、磁黄铁矿、镍黄铁矿,在无菌体系和有菌体系中进行浸出的基础研究。结果表明,在有菌体系中,硫化矿浸出率均比在无菌体系中明显提高。循环伏安法研究认为,黄铁矿、黄铜矿、磁黄铁矿、镍黄铁矿的阳极氧化分解过程均由多步反应组成。浸矿细菌的加入使阳极反应峰电流增加,表明有菌时,更易于硫化矿浸出,且对中间生成的元素硫有氧化作用。Tafel极化研究显示,在有菌体系中,硫化矿电极的腐蚀电位和腐蚀电流密度与在无菌酸性体系中相比均升高。腐蚀电位升高表明,在细菌作用下硫化矿发生化学反应的吉布斯自由能降低；腐蚀电流密度增大则表明在细菌作用下,硫化矿的腐蚀反应速度提高。通过交流阻抗法研究认为,有菌时,黄铁矿、黄铜矿、磁黄铁矿、镍黄铁矿阳极氧化过程为电化学反应与扩散混合控制。有菌体系中矿物表面膜层阻力较无菌体系中降低,说明加入细菌,可促进矿物阳极分解。更多还原

【Abstract】 Bioleaching has some advantages of using resourcefully, low cost and little environmental pollution, so it has already been-researched widely and been applied to the industry domestic and abroad. Four kinds of sulfides single minerals-pyrite, chalcopyrite, pyrrhotite, pentlandite were studied. The bioleaching of sulfide minerals were studied by bioleaching bacteria, the elcetrochemistry mechanisms of suilfide mineral and anode behavior wes studied using carbon paste electrode in acid solution systematically.The experiment adopted HQ0211 bacteria, which was mostly made up of Thiobacillus ferrooxidans. The bacteria cells in the mid-log phase of growth were full, uniform and well-proportioned. At the same time, this period was the optimum time for inoculation. In the steady phase of growth the bacteria cells were curly and asymmetric. Then the bacteria cells were variform and misshapen in the dying phase, the thallis became autolyzing.To the pure mineral of pyrite, chalcopyrite, pyrrhotite, pentlandite, the bioleaching research was carried out in the absence of bacteria and in the presence of bacteria. The effect of various factors on leaching were investigated. The result indicated, the leaching rate of sulfide minerals in the presence of bacteria was higher than that in the absence of bacteria.The intermediate reactions of the anode process of pyrite, chalcopyrite, pyrrhotite, pentlandite, which are measured by CV test. When the bacteria in presence, company with the peak current and reversibility of reaction increasing, The bacteria has contribution to the oxidation of element sulfur formatted during the interniediate process.Tafel curve study showed that the addition of bacteria can make the corrosion potential and corrosion current of sulfide minerals decrease. The corrosion potential elevates indicated, the chemical reaction Gibbs of sulfide minerals in the presence of bacteria was reduced. The corrosion current elevates indicated, sulfide minerals’corrosion reaction rate enhancement was enhanced.The alternating impedance method showed that the anode behavior of pyrite,chalcopyrite, pyrrhotite, pentlandite was a mixed control process by electro-chemical reaction and charge diffusion. The polarized resistance of sulfide minerals in the presence of bacteria was reduced, it showed that the addition of bacteria can contribution to decomposition of anode.更多还原