蒙脱石和沸石界面稀土微量元素赋存机理计算模拟研究

Trace elements, including actinides, rare earth and heavy metals, are often rich on the interface of high specific surface area minerals via adsorption and lattice substitution. However, the interaction mechanism of minerals and elements is not clear, therefore, an efficient and fast technique is need to predict the occurrence and migration of rare earth trace elements in macropores minerals. This subject investigates the interactions of Xinjiang macropores minerals and trace elements, via Grand Canonical Monte Carlo (GCMC), Molecular Dynamics (MD), Virtual Crystal Approximation (VCA), Density Functional Theory (DFT) and Two Dimensional Correlation Analysis (2D-CA) technologies. Therein, the minerals include montmorillonite and zeolite. And the 8-10 kinds of rare earth trace elements include lanthanides, niobium, tantalum, etc. And then, the trace elements placeholder way, crystal structure and surface and interface change mechanism are investigated, via projected density of states (PDOS) and potential function. Typically, a new technique, that is, 2D-CA method is used to calculate the occurrence and migration of rare earth trace elements in high specific surface area minerals. Finally, this subject reveals the law of intrinsic data of montmorillonite (and zeolite) and rare earth trace elements, including electronic structure, atomic concentration and atomic interaction mechanism. The reasonableness of calculated conclusions is verified through trace element content of the assay data calculating via statistical and mathematical methods. This subject will provide a new theoretical idea for investigating the experimental and applied mineral areas, including Xinjiang high specific surface area mineral structure, rare earth trace element analysis, purification and environmental cleanup, etc.

高比表面积矿物常以吸附和晶格内取代方式赋存丰富的锕系、稀土和重金属类微量元素。然而，矿物与微量元素的相互作用机制尚不明确，需要一种高效且快速的研究手段预测矿物内微量元素的赋存与迁移行为。本项目拟综合采用巨正则蒙特卡罗法、分子动力学、虚拟晶格近似、第一性原理等技术解析两类新疆矿物界面（蒙脱石和沸石）与8～10种稀土微量元素（镧系、铌、钽等）的内在相互作用，结合表面电子投影态密度和势函数分析稀土微量元素占位方式、晶体结构与表界面的畸变机理，并提出二维相关技术定量的分析高比表面积矿物内稀土微量元素的赋存与迁移机制。最终揭示蒙脱石（沸石）与微量元素表面电子结构、原子浓度、原子间作用机制等参数之间的内在规律，并采用数理方法统计赋存实验中稀土微量元素的浓度数据，以验证计算结论的合理性。本项目为高比表面积新疆矿物结构、稀土微量元素分析、提纯与环境净化等实验与应用领域提供较为新颖的理论研究思路。

本项目采用巨正则蒙特卡罗法、分子动力学和虚拟晶格近似法优化了新疆矿物（蒙脱石和沸石）界面与微量元素（镧系和锕系）的赋存结构，进而采用第一性原理定性地解析了稀土微量元素占位方式、晶体结构与表界面的畸变机理，并提出了二维相关技术定量的分析微量元素赋存过程中矿物界面和核素的轨道耦合、电子转移和变价机制。最终揭示蒙脱石（沸石）与微量元素表面电子结构、原子浓度、轨道耦合、温度等参数之间的内在规律，并证实统计实验结论的合理性。此类定量数据分析技术已在蒙脱石、沸石、锆石、钙钛矿和尖晶石等矿物赋存微量元素及其络合物等界面体系得到了验证，并正在深入复合界面体系的模拟工作。本项目所获得的蒙脱石和沸石赋存微量元素模拟方法可为矿物吸附剂或去除剂提供吸附位置和吸附模型的理论技术参考，本团队正在根据矿物界面活性位点分布和电子转移机制设计可用于高效、环境友好化、多活性位点的矿物基三元去除剂的理论设计与实际应用领域。