基于胆碱类低共熔溶剂选择性浸出炼钢烟尘回收锌的作用机理研究

Steelmaking dust is an important source of regenerated zinc, and the traditional leaching process is a bottleneck due to its low efficiency, poor leaching selectivity and high energy consumption. Based on the choline chloride as the matrix, the quantum chemical method was used to calculate the structure and properties of choline chloride with different substituents, and a new type of efficient low eutectic solvent of choline chloride suitable for high selective leaching of steel smoke was designed and synthesized. The first principle was used to deeply analyze the surface structure characteristics and reactive sites of the solvent and the mineral, to determine the best mode of action and conditions, and to clarify the interaction mechanism between the new type of deep eutectic solvent and the mineral. The solubility and reaction mechanism of zinc and other metal compounds in deep eutectic solvent were analyzed by FTIR, XRD, XPS and SEM-EDS. By using HSC Chemistry thermodynamic software, the thermodynamics laws of leaching were clarified, and the solid-liquid reaction kinetics model of the leaching process was constructed to reveal the existence forms, chemical equilibrium relations, interaction rules and distribution mechanism of zinc and other different metallic minerals in the leaching solution. Through the research, the selective separation mechanism of zinc was clarified, and a technical prototype for selectively leaching zinc from steelmaking soot by using eutectic solvent was formed. This project has important theoretical and theoretical significance and practical value for the leaching and separation of steelmaking dust in deep eutectic solvent, and it can also provide new ideas for leaching separation and enrichment in other fields.

炼钢烟尘是再生锌原料的重要来源，传统浸锌工艺因效率低、溶浸选择性差、能耗高成为其工业应用的瓶颈。本项目以氯化胆碱为基体，利用量子化学方法计算不同取代基的氯化胆碱的结构与性质关系，设计并合成出适合炼钢烟尘高选择性浸锌的低共熔溶剂；采用第一性原理解析溶剂与锌及其他矿物表面结构特性、反应活性位点，阐明低共熔溶剂与矿物间的相互作用机制；利用FTIR、XRD、XPS、SEM-EDS等检测手段深度解析锌与金属化合物在介质中的溶解性能、反应机理，借助HSC Chemistry热力学软件，探明浸出热力学规律，构建浸出过程的反应动力学模型，揭示浸出液中锌与不同金属矿物的存在形式、平衡关系、相互作用规律和分配机制；阐明锌的选择性分离机理，形成利用低共熔溶剂从炼钢烟尘中选择性定向浸锌的技术原型。本项目对炼钢烟尘在低共熔溶剂中的浸出分离具有重要的理论理论意义与实际价值，也可为其他领域浸出分离富集提供新的思路。

项目以氯化胆碱为基体，利用量子化学方法计算不同取代基的氯化胆碱的结构与性质关系，通过前线分子轨道和电荷布居分析可知，结果表明氯化胆碱与羧酸类氢键供体更容易发生反应，其中氯化胆碱(ChCl)-乙二酸(OA)1:2团簇模型最稳定；采用第一性原理解析对四种金属氧化物(ZnO、Fe2O3、Al2O3、CaO)完全解理面进行建模并分析金属氧化物完全解理面的相关性质，通过建立层状结构得到矿物与药剂相互作用模型，同时通过试验对分子模拟得到的数据进行验证，阐明低共熔溶剂与矿物间的相互作用机制；在此基础上，合成氯化胆碱-丙二酸（ChCl-MA DES）低共熔溶剂，并对其熔点及凝固点、粘度、密度、表面张力、电导率、红外及拉曼光谱等物理性质进行检测及分析，结果表明制备的低共熔溶剂的各项物化性质均在标准范围内，且无新物质生成；以ChCl-MA DES为浸出剂，进行了液固比、搅拌速率、浸出温度和浸出时间等单因素条件试验，采用响应曲面法对浸出体系下不同因素及对应的锌浸出率进行设计，得到了锌浸出的多元二次回归方程，并对试验结果进行分析和论证，结果表明模型可信度高，试验设计满足要求；构建了浸出过程的反应动力学模型，结果表明该浸出过程符合以界面传质和固体膜层扩散为控制步骤的收缩核模型，反应表观活化能为35.92kJ·mol−1，并建立了浸出动力学半经验方程，确定了各因素的影响程度。项目形成了利用低共熔溶剂从炼钢烟尘中选择性定向浸锌的技术原型，为我国类似二次资源的高效回收利用开创一种新的模式。在项目资助下，研究组共发表标注项目编号的论文8篇，其中被SCI收录论文4篇，申请发明专利7件，其中授权国家发明专利4件，参加学术会议3次，依托课题培养研究生6名，其中2名已经获得硕士学位。经费支出合理，略有剩余资金将用于本项目后续研究及成果的支出，较好完成项目原计划目标预期指标。