Assistant Professor

稀土元素及其化合物是使现代技术发生革命性变化的战略材料之一。它们对生产许多技术先进的产品是必不可少的。尽管名字叫稀土，但稀土并不稀有，而且大多数稀土元素丰富地存在于地壳中。问题是，它们同时存在，而且主要集中在世界各地的少数可开采资源中。此外，它们具有相似的物理化学性质，这使得它们的分离和提纯具有挑战性。*湿法冶金工艺是从它们的矿物中提取稀土的典型商业技术。提取过程包括几个步骤，包括前处理、浸出和分离单个稀土元素。中间产物经分离后焙烧得到纯净的稀土氧化物(REO)。然后，REO被还原以生产纯稀土金属(REMS)作为最终产品。*稀土的常见商业分离过程是溶剂萃取法。这项技术的问题是，由于稀土化学性质的相似性，要达到所需的分离水平需要大量的阶段。对于还原步骤，商业技术是在氯化物或氟化物体系中进行熔融电解。这项技术的问题是能源效率低和副产品对环境的影响。*我提出的研究计划将主要集中在稀土提取和生产的两个研究领域：*首先，开发一种创新的熔融电解工艺，在氧化物系统中将REO直接还原为纯REMS。主要目标是提高能源效率，减少对环境的影响。能效的提高可以通过我们建议的电解液(氧化物代替卤化物)来实现。此外，也不需要将稀土氧化物转化为卤化物。此外，建议的工艺是绿色的，因为它会产生O2气体作为副产品。*第二，开发一种新的超临界流体萃取(SCFE)工艺，用于在浸出步骤后选择性地分离所有稀土。其主要目标是开发一种比普通技术更高效、更环保的工艺。与溶剂萃取法相比，超临界流体萃取法的主要优点是分离级数少、副产物少、反应速度快、溶质容易分离。建议的流程不仅可用于从采矿浸出液中提取稀土，还可用于从其他浸出液中提取稀土元素，例如从消费后电子产品的回收中提取稀土元素。*建议的活动(理论和实验)包括但不限于以下内容：*-熔融氧化物电解的电解液设计；*-确定REO和REMS在熔融电解液中的溶解度；*-电解槽设计；*-电化学测试；*-选择超临界流体；*-选择配体；*-SCFE测试和放大。**

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.**