Assistant Professor

点击翻译按钮获取中文摘要

Rare earth elements (REEs) and their compounds are among strategic materials that have revolutionized modern technology. They are essential to the production of many technologically advanced products. Despite the name, REEs are not rare, and most of them occur abundantly in the Earth's crust. The problem is that they co-occur and are primarily concentrated in a few minable resources across the world. Also, they have similar physicochemical properties that make their separation and purification challenging.***Hydrometallurgical processes are the typical commercial technology for REEs extraction from their minerals. The extraction process includes several steps, including pre-treatment, leaching, and separation of individual REEs. After separation, the intermediate products are calcined to obtain purified rare earth oxides (REOs). Then, REOs are reduced to produce pure rare earth metals (REMs) as the final product.***The common commercial separation process for rare earths is solvent extrcation. The problem with this technique is the large number of stages needed to achieve the required separation level because of the similarity between chemical properties of REEs. For the reduction step, molten electrolysis in chloride or fluoride systems is the commercial technique. The problem with this technique is the low energy efficiency and high environmental impact due to by-products.***My proposed research program will mainly be focused on 2 research areas of REEs extraction and production:***First, developing an innovative molten electrolysis process for direct reduction of REOs to pure REMs in an oxide system. The main goal is to improve the energy efficiency and reduce the environmental impacts. Energy efficiency improvement can be achieved through our proposed electrolyte (oxide instead of halide). Also, there will be no need to convert RE oxides to halides. In addition, the proposed process is green, since it produces O2 gas as the by-product.***Second, developing a novel supercritical fluid extraction (SCFE) process for selective separation of all REEs after the leaching step. The main goal is to develop a more efficient and environmentally friendly process compared to common technologies. The main advantages of SCFE compared to solvent extraction are fewer separation stages, less waste by-products, fast reaction rates and easy solutes separation. The proposed process can be applied to extract REEs not only from mining leach solutions, but also from other leach solutions, e.g., those from recycling of post-consumer electronic products.***The proposed activities (both theoretical and experimental) include, but are not restricted to, the following:***- Electrolyte design for molten oxide electrolysis;***- Determination of REOs and REMs solubility in the molten electrolyte;***- Electrolysis cell design; ***- Electrochemical testing;***- Selecting the SCFs;***- Choosing the ligands;***- SCFE testing and scale-up.**