微观结构调控强化钛酸盐电化学解离的基础研究

In order to convert titanium resources shortly and efficiently, direct electrolyzing titanate is an optional method. But the interface diffusion kinetics and the break of Ti-O bond are the main factors to limit the electrolyzing of titanate efficiently. Based on analyzing the stability of titania in molten chloride system, to increase the reaction interface by increasing M/Ti(M=Na,Ca) in the titanate structure and to decrease the Ti-O bond energy by change Na/Ti and ion doping. .The synthesis method of target structure titanate and the structure information will be studied based on using high-temperature on-line XRD and high-temperature on-line Raman. The micro-region analysis and element distribution will be used to study the interface structure evolution in the electrolysis process. The reaction mechanism, kinetics and etc. were studied by using CV, Tafel and electrochemical impedance spectroscopy. To master the structure control of titanate which has high electrolyzing performance is the key point. The results in this item will provide theoretical foundation for converting titanium resources with high efficiency.

典型钛酸盐基矿物直接电解是实现钛资源高效转化的新途径，针对限制钛酸盐电化学解离性能的Ti-O键解离热力学与界面反应-传质瓶颈问题，提出通过增加M/Ti（M=Na，Ca）来强化钛酸盐还原过程中微观传质界面的更新；通过改变Na/Ti以及伴生组分含量调控钛酸盐的空间结构，降低Ti-O键解离能。.借助高温在线拉曼、在线XRD等在线监测与精细分辨技术、Rietveld结构精修方法，研究高温固相反应机理、钛酸盐结构特征信息，掌握特定结构钛酸盐的调控机制；通过微区形貌/结构及元素分布研究钛酸盐的界面结构演变历程；借助循环伏安、交流阻抗、计时电流、Tafel等电化学分析手段解析钛酸盐电极动力学参数与电解还原机理。通过研究钛酸盐微观结构与电化学解离性能之间的匹配制度，揭示可高效电解的钛酸盐结构信息，掌握适用于直接电解的钛酸盐结构调控与定向强化方法，为形成钛资源高效转化新方法提供基础数据与理论支撑。

本项目以钛资源转化过程中间体为原料，通过熔盐电解短流程实现金属钛的短流程转化。针对M-O键稳定性高、难解离等瓶颈，本项目提出了通过微观结构调控强化难熔金属含氧酸盐电化学解离转化新方法，突破了电极/电解质界面反应热力学限制和电极界面传质限制。通过调控钛酸盐中TiO6八面体结构，有效增大Ti-O健长，降低钛酸盐电话学解离热力学难度，利用分子模拟、循环伏安、并联电解等手段验证了不同结构钛酸盐电化学解离热力学难易程度与微观结构的密切关系，揭示了钛酸盐电化学解离程度与Ti-O键越长成正比重要规律，首次实现了钛酸钠熔盐电解制备金属钛过程的深度解离。进一步通过增大钛酸盐中Ca/Ti比，增加电化学还原过程中的O2-扩散通道，有效减小还原时间和能耗，提高电流效率。在此基础上设计了适用于钛酸盐电解的电解槽结构，理论上可以有效提高电流效率并净化熔盐介质，实现熔盐介质的绿色循环。