【作者】 王康林；

【导师】 汪??张勇； 邓天龙；

【作者基本信息】 成都理工大学 ， 应用化学， 2002， 硕士

【摘要】 本文从细菌浸出的热力学、电化学、细菌学原理讨论了黄铜矿细菌浸出的机理，并在银离子存在下，细菌（主要是氧化亚铁硫杆菌）浸出时热力学上的可行性。且从电化学位分析了银离子催化细菌浸出黄铜矿的机理。 研究中发现彭州铜矿矿石成份是黄铜矿—石英—黄铁矿体系，从电化学上分析它是一种非常难浸的铜矿，在只用细菌而不加金属离子催化时，浸出25天后其浸出率只有扣4～9％。它的浸出率低的原因有两个方面：一是从电化学上来看，石英阻碍了黄铜矿与黄铁矿之间接触，因此不利于电化学反应；二是矿石中铁的含量高，在溶液中细菌将黄铁矿中铁转化成三价铁之后，三价铁抑制铜的浸出。将金属银离子加入到浸出体系中，最优条件下浸出25天后其浸出率提高到81％，银离子能提高黄铜矿中铜的浸出率。添加银离子之后，银离子迅速地与硫结合生成硫化银，三价铁离子不断地将硫化银转化为银离子的过程中，也减少了溶液中三价铁离子对细菌浸出过程中黄铜矿对铜的抑制。从电化学来看，Ag₂S在硫化物中电位最正，它可以与黄铜矿等硫化物组成原电池，电动势较大，硫化银的溶解度比很多硫化物要小得多，银离子取代黄铜矿中的金属离子，在矿粒表面生成硫化银与被浸硫化物组成大量的微小原电池，从而促进黄铜矿中铜的浸出。 在细菌浸出黄铜矿时，细菌主要是直接浸蚀矿物，可以用细菌直接浸出机理建立的数学模型来预测黄铜矿的浸出率。在有银离子参与的细菌浸出黄铜矿体系时，银离子主要是先取代黄铜矿中的金属离子，铜离子被不断地浸出，可以用细菌间接浸出机理建立的核收缩模型来预测黄铜矿的浸出率。更多还原

【Abstract】 This thesis discussed the bioleaching mechanism for chalcopyrite from the aspects of thermodynamics .electrochemistry and bacteriology. The bacteria strain used in this study is thiobacillus ferrooxidans. In the presence of Ag ion, the feasibility of bacterial leaching of chalcopyrite in thermodynamics also be debated. Meanwhile, the mechanism and principle of Ag ion catalyzing bacterial leaching of chalcopyrite are analyzed.The Pengzhou copper ore located in Sichuang Province is composed of chalcopyrite-quartz-pyrite. It is difficult to leaching from electrochemistry. The leaching rate is only 4-9% after 25 days leaching when there is only bacteria and without silver ions. The reasons of lower leaching rate locate in two sides: one is that the quartz impede the contact between chalcopyrite and pyrite from the electrochemistry view. So it is disadvantage to reaction by electrochemistry. On the other side, there is too higher iron ions concentration in the copper ores, and the ferric ions restrain the leaching of copper when the bacteria transform the ferrous ions into ferric ions. Under the optimized conditions, the leaching rate of copper significantly increases to 81% after 25 days leaching with Ag ions catalyzing. Therefore the Ag ions can remarkably improve the bioleaching rate of copper in chalcopyrite. When the Ag ions are added to the leaching system, it rapidly combine with sulfuric ores and form precipitated silver sulfide. During the ferric ion ceaselessly transform the silver sulfides into Ag ions, which reduce the ferric ions restraining to copper leaching. In the view of electrochemistry, the silver sulfide voltage is the highest positive in many kinds of sulfides. It can form a million of micro-cell with chalcopyrite, and the solubility of sulfuric silver is lower than other sulfides. Ag ions substitute the metallic ion in the chalcopyrite. So the many of tiny cells composed of silver sulfide with sulfides are produced on the surface of the copper ore, which promote the process of leaching of chalcopyrite.While the bacteria leaching chalcopyrite, the bacteria chiefly corrode the ore surface by direct adsorption, the mathematic model produced by bacterial direct leaching mechanism can well predict the bioleaching rate of chalcopyrite. In the presence of the Ag ions, it can circularly substitute metallic ions of chalcopyrite, the copper ions are produced continuously. So the Ag ions catalyzing bacterial leaching kinetic models produced by bacterial indirect leaching mechanism can well predict the rate of copper hi chalcopyrite.更多还原