LACOR, Department of Materials Engineering, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Porto Alegre, Brazil.
Waste Manag. 2021 Feb 1;120:136-145. doi: 10.1016/j.wasman.2020.11.023. Epub 2020 Dec 7.
The generation of wasted LEDs is expected to grow in the coming years, raising the challenge of recycling and recovering their valuable and critical materials. Due to the low concentration of these materials, the current recycling processes available for LEDs have a significant recovery limitation. This study proposes an innovative, clean and effective physical method to segregate the valuable and critical materials into different fractions while enhancing their concentration: particle size separation followed by electrostatic separation. After the determination of the best electrostatic separation conditions (varying tension and rotation) for each particle size, the final fractions were characterized by acid digestion and ICP-OES analysis. The analysis revealed that the economically valuable elements gold, silver, copper and tin became concentrated in the conductive fractions (80.18%, 94.22%, 96.55% and 93.29% of their total recovered mass, respectively), while the strategic critical elements, gallium, cerium and yttrium became concentrated in the non-conductive fractions (96.15%, 100% and 95.20% of their total recovered mass, respectively). Despite some limitations imposed by the mass losses, this novel route may be important to uncover new recycling alternatives, mainly for critical elements, and to improve the economic viability of the recycling routes.
预计未来几年，废弃 LED 的产生量将增加，这给回收和再利用其有价值和关键材料带来了挑战。由于这些材料的浓度较低，目前可用的 LED 回收工艺回收能力有限。本研究提出了一种创新的、清洁有效的物理方法，通过粒径分离和静电分离将有价值和关键材料分离成不同的部分，并提高其浓度。在确定了每种粒径的最佳静电分离条件（变化的张力和旋转）后，最终的部分通过酸消解和 ICP-OES 分析进行了表征。分析表明，经济上有价值的元素金、银、铜和锡在导电部分集中（分别为其总回收质量的 80.18%、94.22%、96.55%和 93.29%），而战略关键元素镓、铈和钇则在非导电部分集中（分别为其总回收质量的 96.15%、100%和 95.20%）。尽管存在一些由质量损失带来的限制，但这种新方法可能对于发现新的回收替代品，特别是对于关键元素，以及提高回收途径的经济可行性非常重要。
