【作者】 阮仁满；

【导师】 王淀佐；

【作者基本信息】 中南大学 ， 生物工程， 2011， 博士

【摘要】 生物堆浸-萃取-电积提铜技术是上世纪80年代发展的低品位铜资源短流程提取技术,目前在全球得到广泛应用,已有20个以上生物提铜矿山在运行。我国第一座万吨级生物提铜矿山紫金山铜矿于2005年底投入运行,由于矿石性质、当地气候和工程措施等原因,紫金山铜矿生物堆浸系统形成有别于国外同类实践的温度高、铁浓度高和pH值低等特点的浸出体系,并获得良好的技术经济指标。本论文以紫金山铜矿生物堆浸实践为背景,在硫化矿物溶解、亚铁氧化和铁矾生成动力学研究基础上,通过多因素匹配的柱浸实验验证,揭示了紫金山铜矿中铜矿物高效溶解和低成本酸铁平衡的关键控制因素,为次生硫化铜矿生物堆浸实践的优化提供系统的理论依据。紫金山铜矿中主要铜矿物为蓝辉铜矿和铜蓝。在硫酸高铁介质中,蓝辉铜矿第二阶段和铜蓝的活化能较高,因此升温可显著促进其溶解；Fe3+浓度在达到0.1M后,对铜矿物溶解速率的促进作用很小；高温(60℃)下,氧化还原电位对铜矿物溶解速率影响亦很小。因此,在较高的Fe3+浓度下,尽可能提高浸出体系的温度是促进铜矿物溶解的关键路径。紫金山铜矿中黄铁矿含量较高,黄铁矿是浸出体系中酸、铁主要来源,黄铁矿在硫酸高铁介质中的溶解速率与氧化还原电位强相关,氧化还原电位较低时,提高温度对铁矿溶解的促进作用有限。因此,在较高温度下,降低氧化还原电位是紫金山铜矿实现选择性浸出的关键。生物浸出体系中氧化还原电位受浸矿微生物亚铁氧化能力的控制,紫金山铜矿浸矿微生物亚铁氧化动力学研究结果表明,铁浓度、pH值和温度均为浸矿微生物亚铁氧化能力的重要影响因素,高温、高铁浓度和低pH值抑制微生物亚铁氧化活性是紫金铜矿实现低电位的生物学基础；成矾热力学分析和动力学研究结果表明,温度是促进草铁矾生成的关键因素,在紫金山铜矿浸出体系,通过成矾可以将黄铁矿溶解的铁全部转移至矿堆,草铁矾除铁是生物提铜低成本的铁平衡法；柱浸实验结果表明,通过合理匹配温度、铁浓度和pH值,可以实现铜的高效浸出和低成本酸铁平衡。更多还原

【Abstract】 Bioheapleaching-SX-EW process was developed for copper recovery from low grade copper sulfide including more than20mines all over the world since80’s of the last century. In China, the first commercial plant of bioheapleaching-SX-EW with a capacity of10,000t Cu/a in Zijinshan Copper Mine commissioned by the end of2005. Based on mineralogy of the ore and local geography of the mine, distinct engineering operations such as multi-lift permanent stacking in coarse particle size (P80=40mm) without agglomeration and aeration were applied in Zijinshan bioheapleaching practice. Copper was leached efficiently, pyrite dissolution was inhibited and jarosite was formed in the heap by taking advantages of high acidity, high iron concentration, and elevated temperature in the leaching system. The distinct operations and excellent performance probably make Zijinshan copper bioheapleaching practice the first one in the world in which copper was recovered at high efficiency with low activity of microorganism. To reveal key factors which effected the operation in Zijinshan bioheaps, this paper focused on dissolution kinetics of copper sulfides and pyrite, bio-oxidation kinetics of ferrous and kinetics of jarosite formation. The results of kinetics may provide theoretical basis to understand distinct bioehapleaching operation of Zijinshan, and some implication for optimization of similar bioheapleaching practice.The main copper sulfides in Zijinshan were digenite and covellite. In aqueous ferric sulfate the activation energy of copper sulfide dissolution were relative high (covellite96kJ/mol and digenite72kJ/mol), thus elevated temperature was key factor to accelerate the dissolution of copper sulfides; Ferric concentration and redox potential only have a litte positive effect on the dissolution kinetics of copper sulfides. As a result, under high concentration of ferric ion, to increase temperature of the leaching system is the critical path for the copper sulfides dissolution. Relative high content of pyrite (6%) were within Zijinshan copper ores, which was the source of the excessive acid and iron in leaching system. In ferric sulfate solution, the dissolution rate of pyrite has significant correlation with redox potential in order of2.68. Under low redox potential, the dissolution of pyrite was limited even at high temperature. Thus at high leaching temperature, to keep leaching system at low redox potential was the key path for copper competitive bioleaching from pyrite by ferrous oxidation inhibition. Elevated temperature, low pH and high iron concentration could inhibit the iron bio-oxidation, thus lower the redox potential. The analysis of thermodynamics and kinetic experiments showed that temperature was the key factor for jarosite formation. In Zijinshan bioheapleaching system, hydronium jarosite could be readily formed to remove iron inside the heap. Column leaching tests indicated, proper match of temperature, iron concentration and pH, high copper recovery and acid and iron balance at low cost could be achieved.更多还原