Wen Yinghao, Hu Lei, Boxleiter Anthony, Li Dien, Tang Yuanzhi
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States.
Department of Geosciences, Georgia State University, 38 Peachtree Center Avenue, Atlanta, Georgia 30303, United States.
ACS Sustain Resour Manag. 2023 Nov 29;1(1):17-27. doi: 10.1021/acssusresmgt.3c00026. eCollection 2024 Jan 25.
The advancements in high-tech products and pursuit of renewable energy demand a massive and continuously growing supply of rare earth elements (REE). However, REE production from mining is heavily restricted by technoeconomic limitations and global geopolitical tensions. Municipal solid waste incineration ash (MSWIA) has been recently recognized as a potential alternative for REE recovery. This study applies and optimizes a green modular treatment system using organic ligands for effective REE recovery and concentration from MSWIA with minimal generation of secondary wastes. Citrate extracted >80% of total REE at pH 2.0 and ∼60% at pH 4.0. A subsequent oxalate precipitation step selectively concentrated >98% of extracted REE by ∼7-12 times compared to raw MSWIA. Waste byproducts were upcycled to synthesize zeolites, resulting in an overall solid waste volume reduction of ∼80% and heavy metal immobilization efficiency of ∼75% with negligible leaching, bringing the dual benefits of REE recovery and waste management. This work serves as a pioneer study in REE recovery from an emerging source and provides system level insights on the practicality of a simple three-step treatment system. Compared to existing literature, this system features a low chemical/energy input and a light environmental footprint.
高科技产品的进步以及对可再生能源的追求，需要大量且持续增长的稀土元素（REE）供应。然而，采矿生产稀土元素受到技术经济限制和全球地缘政治紧张局势的严重制约。城市固体废物焚烧灰（MSWIA）最近被认为是回收稀土元素的一种潜在替代物。本研究应用并优化了一种使用有机配体的绿色模块化处理系统，以从城市固体废物焚烧灰中有效回收和浓缩稀土元素，同时产生最少的二次废物。在pH值为2.0时，柠檬酸盐提取了总稀土元素的80%以上，在pH值为4.0时提取了约60%。随后的草酸盐沉淀步骤将提取的稀土元素选择性地浓缩至比原始城市固体废物焚烧灰高约7至12倍，浓缩率超过98%。废弃副产品被升级回收以合成沸石，从而使总体固体废物量减少约80%，重金属固定效率达到约75%，浸出可忽略不计，带来了稀土元素回收和废物管理的双重效益。这项工作是从新兴来源回收稀土元素的开创性研究，并提供了关于简单三步处理系统实用性的系统层面见解。与现有文献相比，该系统具有低化学/能源输入和低环境足迹的特点。
