载金黄铁矿化学溶解特性与生物促进机制

Bio-heapleaching process has always been the main research and development focus for pre-oxidation of low-grade refractory gold ore. At present, lengthy preoxidation in heapleaching, low sulfide oxidation rate and efficiency resulting in low rate of gold cyanidation have become a bottleneck for industrial application. This proposal focuses on pyrite and explores the chemical oxidation kinetics of pyrite leaching, with the aim to identify the main factors and controlled parameters affecting pyrite oxidation and explore ways to improve oxidation under certain criteria. With potentiodynamic polarization curves and AC impedance technology, the influence of polarization potential on the rate of corrosion and the influence of microorganism on corrosion resistance will be examined. From the existing efficient bioleaching culture, study of the bacterial consortium behaviour under different leaching conditions and ideal growth condition for iron functional bacteria will be carried out. Together with identification of contributing factors and controlled parameters for bio-heapleaching of pyrite, efficient pre-oxidation of pyrite can be achieved. The outcome of the project not only provides theoretical basis for pre-oxidation bioheapleaching, but also solves the bottleneck in pre-oxidation bio-heapleaching of low grade refractory gold. It will enrich our theoretical understanding of pyrite solution chemistry and biohydrometallurgy.

生物堆浸预氧化技术一直是低品位难处理金矿预氧化研究和开发的热点，目前限制该技术工业化应用的瓶颈是堆浸预氧化时间长、硫化物氧化效率及氧化率低，导致金氰化浸出率低。 项目以载金黄铁矿为研究对象，开展载金黄铁矿化学氧化机理研究，找出影响黄铁矿氧化的主要影响因素及控制环节，探索特定环境因素下提高氧化能力的途径；借助动电位极化曲线及交流阻抗技术，探明极化电位对腐蚀速率的影响规律及微生物对腐蚀阻力的影响，利用已选育的高效浸矿菌，研究不同浸矿条件下微生物菌群的演替规律及铁功能菌优势生长条件。通过查清生物堆浸中黄铁矿氧化的控制性环节及其促进因素，匹配已选育的高效浸矿菌及铁功能菌优势生长条件，实现黄铁矿高效预氧化。 项目成果将为解决低品位难处理金矿生物堆浸预氧化工艺瓶颈提供理论依据，丰富黄铁矿溶解化学及生物冶金理论体系。

项目围绕难处理金矿生物氧化关键技术瓶颈，以载金黄铁矿为对象，采用化学、电化学氧化动力学研究手段，获得载金矿物黄铁矿氧化的最佳条件，查明黄铁矿溶解主要影响因素为温度和氧化还原电位，控制环节为表面化学反应。综合采用循环伏安、线性极化曲线和交流阻抗技术研究了无菌和有菌条件下Fe3+、初始pH和温度对载金黄铁矿电化学行为的影响，结果表明：Fe3+的加入会促进载金黄铁矿的氧化反应，且阳极氧化速率随初始pH增大而加快，随温度升高而增大。.本项目采用已建立的16SrRNA基因实时荧光定量PCR鉴定技术平台，对高效菌株进行了氧化特性研究，揭示了不同浸矿条件下浸矿菌种的氧化规律，明晰了铁功能菌优势生长条件及氧化黄铁矿作用机制。并以黄铁矿生物柱浸试验为依托，建立了预氧化过程多因素耦合方法，形成生物堆浸预氧化技术原型。