离子液体处理黄铜矿的基础研究

Hydrometallurgical treatment of chalcopyrite is the core of hydrometallurgy of copper sulphide. There is a urgent task for hydrometallurgists and relative workers to seek for new and green hydrometallurgical processes for the production of copper operated under ambient atmosphere and low temperature with low consumption of energy, acid and oxygen as well as free of pollutants release. The present project will mainly focus on the following parts: (1)Based on the methodologies of molecular and materials design, Quantum chemical calculation will be used to estimate the micro-molecular information such as equilibrium structure, valence electron structure, characteristics of valence bonds for task-specific choline chloride (ChCl) ionic liquids, chalcopyrite crystal and crystal face. They will be correlated to some important physical chemical properties of ionic liquids such as the molten point, viscosity, conductivity, electrochemical windows. The interactions between the chalcopyrite crystal and designed ionic liquids will be studied to determine active reaction position chalcopyrite crystals and the best interaction ways to the ionic liquids. Various low-price, highly effective bidentate or multidentate N-ligands appended ChCl task-specific ionic liquids for hydrometallurgy of chalcopyrite will be designed and synthesized with low price ChCl reagents. (2) The key physical chemical properties of these ionic liquids and the solubility of chalcopyrite will be measured experimentally and compared with the theoretical predictions, The mechanisms, theomdynamic and kinetics of dissolution process will be elucidated.(3) The basic issues such as the forms, mobilities, inter- or intra-molecular interactions, diffusion mechanisms of ions, cations and anions in digestion ionic liquids will be explored by molecular dynamics simulations and experimental methods to reveal the structural characteristics and the micro-mechanisms of the interactions of the metal ions and cations, anions. The separation and purification methods of valuble element in digestion ionic liquids will be established. (4) The electrodeposition experiments of valuble elements ions in those ionic liquids obtained above will be performed and compared with the previous results. (5) The stability of these ionic liquids in dissolution and electrochemical process will be determined to establish recycling methods and ways of ionic liquids. The goal of this project is to form or establish the new theoretical and technical prototype for highly effective, energy saving and clean utilization of chalcopyrite in hydrometallurgical process.

发展高效、清洁、节能的黄铜矿湿法冶金新理论与新技术是目前冶金领域的研究热点和难点。本项目将以价格低廉的氯化胆碱为基体，根据现代分子和材料设计的研究思路，利用先进的量子化学方法计算不同取代基的氯化胆碱的结构与性质的关系；采用第一性原理研究矿物晶体及表面结构和性质、确定活性点，研究矿物与离子液体的相互作用，确定最佳作用方式和条件；设计并合成出高效、价格低廉的功能离子液体，掌握离子液体的设计准则；探讨黄铜矿物在所得离子液体中的溶解性能、反应机理、溶解过程的热力学和动力学；研究溶出液中物种的存在形式、化学平衡关系、相互作用规律和分配机制；探索有价元素/杂质元素的分离纯净化机制、调控原理和方法；研究有价元素从所设计离子液体中电沉积的机理和方法，揭示电积过程的微观机理；考察反应过程中离子液体性能的变化，实现离子液体循环使用；形成离子液体处理黄铜矿的技术原型，实现黄铜矿资源的高效、节能和清洁利用。

发展高效、清洁、节能的黄铜矿湿法冶金新理论与新技术是目前冶金领域的研究热点和难点，项目提出采用新型绿色溶剂离子液体来处理黄铜矿，完成的工作包括:(1)采用密度泛函理论方法研究了咪唑和胆碱类离子液体的结构与性质的关系。分析了离子液体分子的全局反应活性及局部反应活性，发现咪唑类离子液体的活性点位咪唑环上和阴离子基团上，胆碱类离子液体分子的反应活性点位于胆碱阳离子上;(2)采用第一性原理研究了黄铜矿晶体及其表面的结构特性、确定了活性位点。发现黄铜矿费米能级附近Fe和S的轨道密度较大，Fe和S具有较高活性。Fe与Cu原子相比，Fe原子失去更多的电子，S-Fe键的共价性比S-Cu强，表明S和Fe之间的相互作用较强。第一性原理与分子动力学模拟相结合研究了离子液体与矿物间的相互作用机制，确定了最佳作用方式和条件。发现咪唑类离子液体比胆碱类离子液体更容易发生反应，预测出最佳的浸出剂为硫酸氢类离子液体;(3)研究了不同离子液体中黄铜矿的浸出行为，进一步证实硫酸氢咪唑系列离子液体为最佳浸出剂，与理论预测一致。研究了黄铜矿的溶解热力学及氧化剂对浸出的影响，筛选出双氧水、重铬酸钾、溴酸钾和碘酸钾四种最佳氧化剂;(4)系统研究了离子液体水溶液中黄铜矿氧化浸出行为，探讨了离子液体类型和浓度、粒度、转速、温度和氧化剂浓度等因素对浸出的影响，揭示了浸出过程的动力学机理。发现有效浸出剂的选择依赖于氧化剂，与四种氧化剂对应的最佳的浸出剂分别为[Hmim]HSO4，[Emim]HSO4，[Bmim]HSO4和[Emim]HSO4。采用这四种氧化剂2小时内Cu的浸出率均可达到90%以上;(5)考察了离子液体溶液中离子的存在形式，迁移输运及其对体系物化性质的影响;(6)考查了浸出后的离子液体体系的循环使用，发现浸出液经活性炭处理后循环 4 次仍不会导致离子液体的降解和Cu浸出率的降低。研究工作进一步表明离子液体作为一种可设计选择性好、易循环利用的绿色溶剂用于黄铜矿湿法冶金可显著缩短浸出时间提高Cu浸出率，实现黄铜矿资源的高效、节能和清洁利用。发表学术论文18余篇,SCI/EI收录7余篇,授权发明专利4项，参加国内外学术会议7次并作分会报告，毕业研究生5名，在读5人.团队能力和水平得到进一步提升，负责人遴选为博导，获云南省引进高层次人才工作经费和省中青年学术技术带头人后备人才项目支持,团队成员晋升高级职称。