Electrochemical Separation and Recovery of Metals from Liquid Alloys

这项研究将探索更快、更安全、更可持续的贵金属回收方法。这将引导研究人员了解材料加工背后的科学。由于这种新方法的生产率更高，可以利用它来造福美国制造业经济。贵金属在电子产品中越来越普遍；不幸的是，这些设备的使用寿命很短，因为它们很快就会被新的型号所抛弃。这项拨款支持研究一种叫做电冶金的金属回收新方法，这种方法利用电场从废料中分离和回收金属。与现有的金属分离方法相比，这种方法具有实质性的优势，这些方法涉及燃烧或强酸溶解。这项基础研究将研究如何利用电力选择性地回收和净化电子废物中含有的许多不同金属，以贵金属（金和银）为目标。将过程科学、热力学、化学工程和电化学等领域结合在一起，这项跨学科的工作将为多个领域的工程师带来新的知识。所制定的基本原则可以扩展到航空航天和国防，建筑和技术领域的金属可持续生产，为美国经济和公众健康带来巨大利益。此外，在这项工作中开发的计算工具将作为热力学的免费教学工具广泛使用。这个在线工具将接触到广泛和多样化的受众，使学生能够追求科学和工程。与其他回收方法相比，电冶金有可能将能源消耗减少80%，回收所需时间减少10倍。然而，为了实现这些好处，必须更好地了解液态合金电极的电化学，以便能够控制在电子废物（电子废物）中存在的许多金属中，哪种金属被回收利用。此外，将研究一种高温溶剂，这种溶剂首次能够同时容纳熔融的金、铜和银。本研究旨在了解潜在的动力学、传输和热力学因素，这些因素决定了哪些物质在阴极被还原，哪些物质在由熔化的电子废物制成的阳极被氧化。一个新的模型，预测哪些金属是稳定的，其比例将被开发出来。此外，该过程中的限速步骤将通过实验电化学测量进行验证。先进的电化学表征技术，如交流循环伏安法，以及传统的计时安培法和电动势测量，将在实验中使用。多物理场建模、热力学计算和相图预测将用于迭代和优化计算端的工艺条件。总之，实验和建模技术将告知熔融贵金属电化学行为的基本原理。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The research made possible by this award will explore faster, safer, and more sustainable methods of precious metal recycling. This will guide researchers toward understanding the science behind the processing of materials. By virtue of its higher productivity, this new method can be utilized to the benefit of the US manufacturing economy. Precious metals have seen an increased prevalence in electronics; unfortunately, these devices have short lifetimes as they are quickly discarded for newer models. This grant supports investigation of a new method for metal recycling, called electrometallurgy, which makes use of electric fields to separate and recycle metals from scrap. This approach provides substantial benefits over existing methods for metal separation, which involve combustion or harsh acid dissolution. This fundamental research will investigate how electricity can be used to selectively recycle and purify the many different metals contained in electronic waste, targeting the precious metals (gold and silver). Bringing together the fields of processing science, thermodynamics, chemical engineering, and electrochemistry, this cross-disciplinary work will bring new knowledge of benefit to engineers in multiple fields. The basic principles developed can be extended to the sustainable production of metals for aerospace and defense, construction, and technology, presenting a large benefit to the US economy as well as public health. Furthermore, the computational tools developed in this work will be made widely available as free teaching tools for thermodynamics. This online tool will reach a broad and diverse audience, empowering students to pursue science and engineering. When compared to other recycling methods, electrometallurgy has the potential to reduce the energy use by 80x and the time needed for recycling by a factor of 10. In order to realize these benefits, however, the electrochemistry of liquid alloy electrodes must be better understood in order to be able to control which metal, among the many present in electronic waste (e-waste), is recycled. Furthermore, a high-temperature solvent, the first of its kind able to accommodate molten gold, copper, and silver simultaneously, will be investigated. This research aims to understand the underlying kinetic, transport, and thermodynamic factors that determine which species is reduced at the cathode and oxidized at the anode made of melted e-waste. A new model predicting which metals are stable and in what proportions will be developed. In addition, the rate-limiting step in the process will be verified with experimental electrochemical measurements. Advanced electrochemical characterization techniques, such as alternating current cyclic voltammetry, alongside traditional chronoamperometry and electromotive force measurements, will be employed experimentally. Mutiphysics modeling, thermodynamic calculations, and phase diagram predictions will be used to iterate and optimize process conditions on the computational side. Together, both experimental and modeling techniques will inform the underlying fundamentals of electrochemical behavior of molten precious metals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.