Assistant Professor

助理教授

• 批准号: RGPIN-2015-03936
• 负责人: Azimi, Gisele
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680301
• 关键词: Assistant; Professor

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.**

稀土元素及其化合物是革新现代技术的战略材料之一。它们对于生产许多技术先进的产品是必不可少的。尽管叫稀土元素，但稀土元素并不罕见，而且大多数稀土元素大量存在于地壳中。问题是它们同时出现，并且主要集中在世界各地的几种可开采资源中。此外，它们具有相似的物理化学性质，这使得它们的分离和纯化具有挑战性。湿法冶金工艺是从稀土矿物中提取稀土元素的典型商业技术。提取过程包括几个步骤，包括预处理、浸出和分离单个稀土元素。分离后的中间产物煅烧得到纯化的稀土氧化物（REOs）。然后，reo被还原成纯稀土金属（REMs）作为最终产品。常用的商业分离稀土的方法是溶剂萃取。这种技术的问题是，由于稀土元素的化学性质相似，需要大量的分离级才能达到所需的分离水平。对于还原步骤，在氯化物或氟化物系统中熔融电解是商业技术。这种技术的问题是低能源效率和高环境影响由于副产品。***我提出的研究计划将主要集中在稀土提取和生产的2个研究领域：***第一，开发一种创新的熔融电解工艺，用于在氧化物体系中直接将REOs还原为纯REMs。主要目标是提高能源效率，减少对环境的影响。能源效率的提高可以通过我们提出的电解质（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，提议的过程是绿色的，因为它产生氧气作为副产品。***第二，开发了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分离所有稀土元素。主要目标是开发一种比普通技术更有效和更环保的工艺。与溶剂萃取相比，SCFE的主要优点是分离阶段少、副产物少、反应速度快、溶质分离容易。所建议的方法不仅可用于从采矿浸出液中提取稀土元素，也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（包括理论和实验）包括但不限于以下内容：***-用于熔融氧化物电解的电解质设计；***-测定REOs和REMs在熔融电解质中的溶解度；***-电解池设计；***-电化学测试；***-选择SCFs；***-选择配体；***- SCFE测试和放大