Brown Rebecca M, Struhs Ethan, Mirkouei Amin, Raja Krishnan, Reed David
Environmental Science Program, University of Idaho, Idaho Falls, ID 83402, USA; Department of Materials Recovery and Recycling, Idaho National Laboratory, Idaho Falls, ID 83402, USA.
Department of Mechanical Engineering, University of Idaho, Idaho Falls, ID 83402, USA.
Sci Total Environ. 2024 Sep 20;944:173945. doi: 10.1016/j.scitotenv.2024.173945. Epub 2024 Jun 12.
Rare earth elements are crucial for the development of cutting-edge technologies in various sectors, such as energy, transportation, and health care. Traditional extraction of rare earth elements from soil and ore deposits primarily involves chemical leaching and solvent extraction. Environmental-based biological rare earth element extraction, such as bioleaching, can be a promising alternative to mitigate pollution and hazardous wastes. We investigated the sustainability aspects (techno-economic and environmental impact) of mixed rare earth metals production from soil in Idaho, USA. We focused on the bioleaching of surface soil using techno-economic analysis and "cradle-to-gate" life cycle assessment. The system boundary included collection, transportation, bioleaching, and molten salt electrolysis. Our results revealed that the mixed rare earth metals (including Nd, Ce, and La) production costs approximately $10,851 per metric ton and generates 1.9 × 10 kg CO eq./ton. Our results showed that most emissions are due to energy consumption during bioleaching. Over a 100-year time horizon ultrasound-assisted bioleaching can reduce greenhouse gas emissions by approximately 91 % compared to the traditional bioleaching process by decreasing the organic acid leaching process time and energy consumption. Our work demonstrates that higher solids loading in leaching with biological reactions can promote economic feasibility and reduce chemical wastes.
稀土元素对于能源、交通和医疗保健等各个领域的前沿技术发展至关重要。从土壤和矿石矿床中传统提取稀土元素主要涉及化学浸出和溶剂萃取。基于环境的生物提取稀土元素，如生物浸出，可能是减轻污染和有害废物的一种有前景的替代方法。我们研究了从美国爱达荷州土壤中生产混合稀土金属的可持续性方面（技术经济和环境影响）。我们使用技术经济分析和“从摇篮到大门”的生命周期评估，重点研究了表层土壤的生物浸出。系统边界包括收集、运输、生物浸出和熔盐电解。我们的结果表明，混合稀土金属（包括钕、铈和镧）的生产成本约为每公吨10,851美元，每吨产生1.9×10千克二氧化碳当量。我们的结果表明，大多数排放是由于生物浸出过程中的能源消耗。在100年的时间范围内，与传统生物浸出过程相比，超声辅助生物浸出通过减少有机酸浸出过程时间和能源消耗，可将温室气体排放量减少约91%。我们的工作表明，在生物反应浸出中提高固体负载量可以提高经济可行性并减少化学废物。
