热活化黄铁矿与铜离子反应表面钝化的控制因素与作用机制

Nanostructured monoclinic pyrrhotite which derived from the thermal treatment of natural pyrite has a high specific surface area and reactivity. It has shown a great potential to be a reactive mineral material for the removal and recovery of heavy metals from wastewater. However, surface passivation of the thermally modified pyrite (MPy) inhibits its complete reaction with heavy metals, reducing metal contents in the used MPy and its recovery value. The reaction extent of MPy and the Cu contents in the used MPy as a function of different factors will be investigated by batch and column experiments. These factors include pH, initial Cu concentrations, dissolved oxygen, temperature, impurity ion concentrations (i.e. iron, calcium, sulfate), solid-liquid ratios, and hydraulic retention time. Reaction kinetics will also be studied by combined quantitative analysis of the solution and solid components. Techniques including X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy will be used to demonstrate the phase composition, morphology, intergranular pore structures, and Cu distribution of the secondary phase, and its interface relationship with the original phase under above factors. This study will elucidate the factors and mechanisms of surface passivation between MPy and Cu, providing a theoretical basis for the application of MPy as a novel material for the recovery of heavy metals. Moreover, new methods for preventing or attenuating the surface passivation will be explored.

黄铁矿热活化转化为多级孔纳米结构化单斜磁黄铁矿，具有很高的比表面积和反应活性，作为反应性矿物材料在固定和回收重金属方面具有巨大的应用潜力。然而反应过程中热活化黄铁矿表面钝化抑制了其与重金属离子完全反应、降低了最终产物中重金属含量及回收价值。本项目拟通过静态和动态实验考察溶液pH值、铜离子浓度、溶解氧浓度、温度、杂质离子浓度、固液比、水力停留时间对热活化黄铁矿反应程度及产物中铜含量的影响，并结合溶液和固体成分定量分析进行反应动力学研究；通过XRD、XPS、场发射扫描电镜、高分辨透射电镜等技术手段，查明上述不同条件下热活化黄铁矿与铜离子反应新生膜层物相组成、晶体形貌和粒径、粒间孔隙特征、铜元素在颗粒中的分布、新生物相与原始物相的界面关系。综合分析揭示热活化黄铁矿与铜离子反应表面钝化的控制因素与作用机制，探索阻止或减弱钝化效应的新方法，为热活化黄铁矿作为新型功能材料应用和重金属回收奠定理论基础。

从安徽铜陵、庐江等地矿山采集黄铁矿及浮选获得的硫精矿粉若干件大样。XRD测定样品物相组成，X射线荧光光谱、电子探针和化学分析测定样品中铁、硫、砷等量元素含量，用原子吸收、原子荧光光谱测定样品中的微量元素，了解样品的化学成分和元素赋存状态。通过管式炉无氧条件下黄铁矿热活化分解，制备系列磁黄铁矿样品，研究煅烧温度、气氛对热活化黄铁矿产物微结构、特性的影响规律；通过静态和动态实验考察溶液pH值、铜离子浓度、溶解氧浓度、温度、杂质离子浓度、固液比、水力停留时间对热活化黄铁矿反应程度及产物中铜含量的影响，并结合溶液和固体成分定量分析阐明反应动力学，解析热活化产物微结构与铜离子反应动力学之间的内在联系。研究铜离子浓度、pH值、溶解氧、温度、杂质离子（铁、钙、硫酸根）浓度、固液比、水力停留时间对热活化黄铁矿与铜离子反应程度和产物中铜含量的影响规律。通过XRD、XPS、场发射扫描电镜、高分辨透射电镜等技术手段，查明上述不同条件下热活化黄铁矿与铜离子反应新生膜层物相组成、晶体形貌和粒径、粒间孔隙特征、铜元素在颗粒中的分布、新生物相与原始物相的界面关系。综合分析揭示热活化黄铁矿与铜离子反应表面钝化的控制因素与作用机制，探索阻止或减弱钝化效应的新方法，为热活化黄铁矿作为新型功能材料应用和重金属回收奠定理论基础。