Nd-Dy incorporation in zircon and pyrochlore: implications for melt/crystal REE partitioning and REE extraction strategies

This project aims at obtaining a detailed information on the local structure of Nd and Dy in Zircon (ZrSiO4) and Pyrochlore ((Ce,Ca,Y)2(Nb,Ta)2O6(OH,F)). Due to similar geochemical behaviour of REEs, it is notoriously difficult to separate them. Detailed structural informationon the local environment of Dy and Nd in crystalline phases like zircon and pyrochlore and in silicate melts can help in obtaining deeper insight on the mechanisms affecting REE partition coefficients between melts and crystalline phases growing in the melts. This proposal is the first step for a larger project aiming at studying REE structural role in crystals and silicate glasses and REE partition coefficients between crystals and silicate melts. The structural results we will obtain from the proposed measurements can help to understand the mechanisms affecting REE partition coefficients between crystals and melts and, thus can help finding new routes for REE extraction from industrial and electronic wastes.

本项目旨在获取锆石（Zircon, ZrSiO₄）与烧绿石（Pyrochlore, (Ce,Ca,Y)₂(Nb,Ta)₂O₆(OH,F)）中钕（Nd）与镝（Dy）的局域结构详细信息。由于稀土元素（Rare Earth Elements, REE）具有相似的地球化学行为，其分离工作历来极具挑战性。针对锆石、烧绿石等晶相以及硅酸盐熔体中钕与镝的局域配位环境的详细结构信息，有助于深入理解调控熔体与熔体中生长的晶相间稀土元素分配系数的作用机制。本申请是一项大型研究项目的第一步，该大型项目旨在探究稀土元素在晶体与硅酸盐玻璃中的结构角色，以及晶体与硅酸盐熔体间的稀土元素分配系数。通过本次拟开展的测量所获得的结构结果，将有助于阐明调控晶相与熔体间稀土元素分配系数的作用机制，进而为从工业废料与电子废弃物中提取稀土元素提供全新的技术路径。