硫膜消除动力学与微生物促进硫砷铜矿溶解机制

Arsenic copper sulfide, carrier of gold and copper, is an important mineral resource. Enargite is a typical copper sulfide bearing arsenic, contains both valuable copper metal and arsenic. This potentially harmful element As has direct impact on metallurgical production and the environment. Firstly, microorganism population will be monitored using the established real-time Fluorescence quantitative-PCR technique of 16S rRNA gene identification. Secondly, investigation of the adsorption properties of micro-organism and mineral surfaces will be carried out by analysis of Zeta potential, contact angle and surface morphology in the bio-leaching system. Then the adsorption model can be established and the mechanism of enargite bioleaching will then be determined. Thirdly, this research will focus on leaching kinetic of enargite by application of different bacteria. It is intended to explore the effect of microorganism, pulp density, temperature, iron concentration, pH and redox potentials on copper and arsenic leaching. From this, limiting key factors for enargite bioleaching can be determined. Speciation of sulfur on the mineral surface was investigated by AFM, SEM, XPS and XRD et al. The sulfur film elimination kinetic and the promotion mechanism of enargite bioleaching will be determined. Fourthly, by considering microbiological, chemical and physical factors, enargite bioleaching control in the complex bioleaching system will be explained. Hence, a clean and efficient resource development for enargite can be based.

含砷硫化铜矿是一种重要的矿产资源，是金、铜等有价金属的有效载体矿物。硫砷铜矿是典型的含砷硫化铜矿，既含有价金属铜，又有潜在有害元素砷，是影响选冶生产和环境安全的重要铜矿资源。采用16S rRNA基因实时荧光定量PCR鉴定技术监测浸矿微生物种群。通过微生物浸矿体系下Zeta电位、接触角和表面形貌的研究分析，探讨微生物与硫砷铜矿表面的吸附性能，构建吸附动力学模型，明确硫砷铜矿生物浸出机制；采用不同浸矿菌研究硫砷铜矿生物浸出动力学，探讨菌种、矿浆浓度、温度、铁浓度、pH、氧化还原电位等因素对铜、砷浸出行为的影响，确定硫砷铜矿生物浸出的限速关键因素；借助AFM、SEM、XPS、XRD等手段分析氧化表面硫的形态与转变，确定硫膜消除动力学和生物促进硫砷铜矿溶解的机理；耦合微生物、物理和化学等因素，探明复杂生物浸矿体系下硫砷铜矿浸出控制方法，为硫砷铜矿资源清洁高效开发利用提供科学依据。

硫砷铜矿是典型的既含有价金属铜，又有潜在有害元素砷的硫化铜矿，对选冶生产和环境安全具有重要影响。本项目采用驯化浸矿菌进行硫砷铜矿表面吸附性能研究，吸附平衡数据拟合符合Freundlich模型，Zeta电位测定与FT-IR图谱分析结果表明，硫砷铜矿驯化菌表面带有较多正电荷，蛋白含量大，生物吸附对硫砷铜矿生物浸出具有重要影响，间接接触作用是主要浸出机制。硫砷铜矿细菌浸出的限速关键因素为温度、矿浆浓度及初始二价铁浓度。浸出过程矿物表面多硫化物和单质硫的相对原子含量变化揭示了浸出过程硫形态变化与细菌消除硫膜促进硫砷铜矿溶解机理。在此基础上，形成了复杂生物浸矿体系中硫砷铜矿快速浸出方法。项目研究成果为低品位硫化铜矿生物堆浸过程控制及浸矿场地土壤污染成因与治理提供了强有力的技术支撑。