高硅复杂物料草酸体系下选择性分离镓锗的应用基础研究

Zinc refinery residue is a typical complex material containing gallium and germanium with high silica. The economic value and environmental benefits of its comprehensive utilization have become increasingly prominent. However, there are many problems such as low recovery rates of gallium and germanium, high energy consumption and tediously flow in existing smelting processes. A new oxalic acid based extraction process has a great industrial application potential to treat the high silica complex material, which can achieve selective separation of gallium and germanium. However, there are few studies on coordination behaviors between oxalate and metal ions (gallium, germanium, silicon, iron) and their interaction rules of metal complex ions in oxalic acid medium, which is difficult to provide theoretical support for the accurate regulation of gallium and germanium recovery. For these reasons, the structures of metal complexes and related thermodynamic parameters in oxalic acid medium were firstly confirmed using the methods of combining the experiments with Materials Studio software simulation, which can confirm the coordination behaviors of oxalic acid with gallium, germanium, silicon and iron. Bashed on these researches mentioned above, the phase equilibrium of high silica complex material leching system, iron purification system, and solvent extraction system can be constructed using CALPHAD optimization methods. The phase equilibrium theories can easily explain the interaction rules between metal coordination ions, and the comprehensive regulatory mechanisms of selective separation of gallium and germanium will be established. Finally, a systematic and basic theory for extraction of gallium and germanium in oxalic acid medium will be formed. Moreover, all above researches will promote industrial application of the novel process.

浸锌渣是典型含镓、锗高硅复杂物料，综合利用的经济价值和环境效益日益凸显。但现有冶炼工艺提取镓、锗多存在回收率低、能耗高、流程冗长等问题。项目提出草酸体系下回收镓、锗新思路，可实现镓、锗选择性分离，其工业应用潜力较大。但草酸体系下镓、锗、硅、铁等离子配合行为及各配合离子间相互作用规律不明，难为镓、锗高效选择性分离及其准确调控提供理论支撑。为此，本项目拟首先采用实验和Materials Studio软件模拟相结合的方法获得草酸盐体系下金属配合离子的结构及相关热力学参数，明确草酸根与镓、锗、硅、铁等金属离子的配合行为；在此基础上以CALPHAD优化方法构建高硅复杂物料分解体系、净化除铁体系、镓锗萃取体系等所涉及的多相平衡关系，揭示出草酸体系下各配合离子间相互作用规律，建立起高效选择性分离镓、锗的调控机制，最终形成系统的草酸体系下提取镓、锗的基础理论。研究所得结果有助于推动新工艺的工业化应用。

镓、锗为全球战略性资源，但自然界中极少存在独立的镓、锗工业矿床，镓、锗主要从锌、铝、铜等有色金属冶炼副产物中回收。浸锌渣是典型含镓、锗高硅复杂物料，综合利用的经济价值和环境效益日益凸显。但现有冶炼工艺提取镓、锗多存在回收率低、能耗高、流程冗长等问题。为此，本项目团队开发了草酸体系下回收镓、锗新工艺，为实现对新工艺的准确调控，本项目采用热力学计算、仿真、实验等手段，对草酸体系下镓、锗、硅、铁等配合离子的种类、 结构、热力学参数及其溶解平衡关系开展系统的研究，明确草酸根与镓、锗、硅、铁等金属 离子的配合行为，揭示出草酸体系下各配合离子间相互作用规律，建立起高效选择性分离镓、锗的调控机制，最终形成系统的草酸体系下高效提取镓、锗的基础理论。同时本项目对镓锗回收过程产生的含汞危废进行资源化处置，汞和银的回收率在95%以上；对废水中的草酸进行有效回收，草酸回收率达80%以上，这使得新工艺镓、锗回收成本显著降低。通过全流程优化，实现了镓、锗经济、高效、绿色提取，达到炼锌废渣的高效综合利用的愿景。本项目研究所总结的研究方法及获得的热力学基础数据，也为稀土、锂等二次资源循环利用工艺的革新提供理论指导。